Wiley: Functional Ecology: Table of Contents

Nitrogen addition alters adaptive strategies of a dominant plant species in an alpine meadow via shifts in traits and trait coordination

Hao Shen, Shikui Dong, Hanzhong Zheng, Qiyun Wang — Sun, 07 Jun 2026 23:31:00 -0700

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Abstract

Nitrogen (N) deposition significantly impacts plant functional traits in alpine meadows, yet the adaptive strategies of dominant species remain unclear. Understanding these strategies is crucial for predicting alpine grassland vegetation changes and ecosystem functioning under increasing N enrichment. However, little is known about how different levels of N deposition affect the eco-physiological responses of key species in alpine environments. We conducted a field experiment in an alpine meadow on the Qinghai-Tibetan Plateau to examine how the dominant grass Leymus secalinus adjusts leaf structure, physiology and carbon-nutrient allocation under simulated N deposition. Three N addition levels (0, 8, 72 kg N ha⁻¹ year⁻¹) were applied, and multiple plant eco-physiological traits including leaf anatomical traits, morphological traits, photosynthetic traits and nitrogen and carbon traits were measured to quantify shifts in trait coordination under different N addition levels. Low N addition (8 kg N ha⁻¹ year⁻¹) induced significant positive responses in leaf thickness, cuticle thickness, vascular bundle sheath thickness, leaf area (LA) and water-use efficiency (WUE), while high N addition (72 kg N ha⁻¹ year⁻¹) enhanced net photosynthetic rate (Pn), stomatal conductance (Gs), plant height, LA and leaf N content. Non-structural carbohydrate content decreased under both N levels, while WUE decreased under high N addition. Principal component analysis revealed nitrogen-dependent shifts in trait coordination, with anatomical and morphological traits governing plant responses under low N addition, in contrast to physiological traits that predominated under high N addition. In addition, correlation networks showed increased trait connectivity and integration under high N addition. Our study suggests that L. secalinus employs contrasting adaptation strategies along a conservative-acquisitive continuum: a conservative, structure-focused approach under low N deposition and an acquisitive, growth-oriented strategy under high N deposition. The observed trait plasticity in both trait values and trait coordination likely contributes to this species' dominance under high N deposition. These results highlight the importance of considering N deposition intensity and trait coordination when predicting plant functional changes and ecosystem responses to ongoing N enrichment in alpine grassland ecosystems.

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Cover Picture and Issue Information

Tue, 02 Jun 2026 22:26:01 -0700

Cover image: The photosynthetic sponge species Aplysina archeri (Credit: Benjamin Mueller)

This cover image is provided by the authors of the article Sponges are celebrated heterotrophs but also key primary producers on changing coral reefs (https://doi.org/10.1111/1365-2435.70311), which features in this issue. Achlatis et al. found that half of the sponge species on the reefs of Curaçao contribute to 11% of gross primary productivity of the entire benthic ecosystem. They argue that, together with their heterotrophic carbon capturing, the widespread presence and anticipated contribution of photosymbiotic sponges to coastal ecosystem productivity calls for further investigation and for revision of benthic food web models and carbon budgets.

Inducible defences, chemical aposematism and the spatial ecology of plant–herbivore interactions in tall goldenrod, Solidago altissima L.

André Kessler, Katja Poveda — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Plants can respond to herbivore attack by inducing resistance traits that affect subsequent herbivore performance and behaviour. Here, we investigate how such induced responses in Solidago altissima L. (tall goldenrod) function to spread herbivore damage more evenly across plant populations, thereby reducing the amount of herbivory for each individual plant. In field and laboratory experiments with Trirhabda virgata J. L. LeConte (1865) beetle larvae, we demonstrate that herbivory induces strong resistance in S. altissima, resulting in reduced larval growth and behavioural avoidance of previously damaged plants. Volatile organic compounds (VOCs) emitted from damaged plants serve as olfactory cues for larval decision-making, suggesting a form of chemical aposematism informing the beetles' movement through the plant population. Beetle larvae use these cues to move away from damaged plants and preferentially colonize undamaged neighbours, particularly when plants are connected by overlapping foliage. Isolated plants, by contrast, experience significantly more damage due to reduced larval emigration. With seasonal surveys, we found a shift from clumped to a more even herbivore distribution, driven by plant-induced resistance and VOC signalling. These results support a ‘risk-spreading’ function of inducible resistance, contingent on herbivore mobility and plant connectivity, and offer an alternative ecological framework for the evolution of inducible plant defence traits beyond traditional cost-saving hypotheses. This research underscores the role of plant chemical signalling and spatial structure in shaping herbivore–plant interactions and community dynamics.

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The multiple dimensions of intraspecific variation in seed dispersal

Catharina Y. Utami, Cyrille Violle, Denis Vile, François Vasseur — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Seed dispersal plays a central role in plant ecology and evolution, and understanding its variation is key to predicting species demography and range dynamics. However, dispersal is difficult to measure, and most modelling and field studies assume uniform dispersal within species, ignoring individual variation. Yet dispersal potential can differ strongly among individuals within species. More empirical data at the individual level are therefore needed to quantify the magnitude of intraspecific variation and its ecological underpinnings. We developed a wind dispersal trial to capture full individual seed dispersal distributions for 107 Arabidopsis thaliana genotypes originating across the species' European range. We used these data to (1) assess variation in seed dispersal patterns via dispersal kernel, (2) estimate dispersal kernel heritability, (3) identify how strong and widespread are the major phenotypic drivers of intraspecific variation in dispersal kernel, including (4) the relative contribution of intra-individual versus inter-individual phenotypic variation and (5) test whether spatial, demographic or environmental factors structure dispersal traits. Dispersal kernel properties, mean distance, skewness, kurtosis and standard deviation, varied significantly across genotypes and showed considerable heritability. These components were not uniformly controlled by the same set of traits. Mean distance, skewness and kurtosis that reflect aspects of average and longer distance dispersal were primarily driven by a few tightly linked traits, especially plant height and fecundity. In contrast, standard deviation (SD), which captures the variability in dispersal distance, was influenced by a broader and more complex set of predictors, including within-individual variation in seed roundness and seed size. We found no clear geographic or demographic structure of dispersal kernel properties. However, SD, which is related to post-dispersal sibling distance, was significantly associated with environmental unpredictability, suggesting it may represent an environmentally responsive and potentially adaptive strategy. Our findings reveal that, even within a single species and dispersal mode, dispersal varies substantially and is shaped by distinct trait dimensions. We highlight the need to account for intraspecific variation in seed dispersal potential and suggest that incorporating variation in kernel properties or the underlying trait complexity could improve predictions of species spread, persistence and adaptive capacity in changing environments.

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Developing together: The elementome and biogeochemical niche of the mutualistic occupants of a fig microcosm

Manasa Kulkarni, Nehal Vijay Naik, Jyothilakshmi Vadassery, Renee M. Borges — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

In brood-site pollination mutualisms, where flowers provide nutrition and shelter to pollinator offspring in exchange for pollination, resource allocation to inflorescences is directly related to plant and pollinator fitness. We determine resource allocation to components of an enclosed monoecious Ficus inflorescence or syconium that, besides seeds, also houses and provides nutrition to pollinator wasp offspring, each developing within individual uniovulate galled flowers. Besides biomass, we determine elemental concentrations as parameters of resource allocation. For the first time, we apply the biogeochemical niche (BN) concept to a mutualism and construct the BN of syconial occupants using the elementomes and stoichiometric ratios of plant, seed and pollinator tissue. We predicted that BNs of seeds and galls containing wasps should differ due to differences in tissue type, facilitating their co-development. We also measure trophic stoichiometric ratios (TSRs) for various elements to determine resource mismatch between consumers and resources. We found that the syconium wall, which insulates and protects developing seeds and wasps, constituted 58% of syconial biomass. Individual pollinators and their galls were significantly heavier than seeds indicating that their development is resource-intensive. As predicted, seeds and adult female pollinators had significantly different BNs, highlighting differences in nutritional needs of these mutualistic occupants within a shared nutrient-providing resource. Pollinators had significantly lower C:N and C:P ratios than the syconial wall indicating limitation of N and P within host resources. The BN of pollinator wasps was distinguished by significantly higher concentrations of nitrogen, phosphorus, zinc and sulphur compared to the syconium wall or seeds. TSRs of >4 for nitrogen and sulphur highlight the heightened resource mismatch that pollinators likely face for these elements during their development. We found no overlap in the BNs of male and female pollinator wasps, likely due to their starkly different anatomical and functional traits. Overall, our study demonstrates how BNs and TSRs can reveal trading of resources within mutualisms highlighting non-overlapping requirements for elements and the potential limitations they can pose for resource providers and consumers. These parameters can serve as common currencies for comparisons across mutualistic interactions.

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Sponges are celebrated heterotrophs but also key primary producers on changing coral reefs

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Trophic interactions and nutrient cycling lay at the heart of ecosystem health and biodiversity. In recent years, our understanding of these drivers has been repeatedly challenged by rapid and unanticipated climatic effects, combined with an increasing awareness that carbon acquisition by living organisms often does not meet the textbook duality of autotrophy versus heterotrophy. On coral reefs, mixotrophic feeding that combines these two strategies is widespread. Mixotrophy has been largely overlooked in sponges, which are ecologically important and highly abundant animals that are commonly celebrated both as efficient heterotrophic feeders as well as climate-change winners in these rapidly declining ecosystems. Many Caribbean sponges associate with photosynthetic symbionts, and we here combine oxygen flux measurements with chlorophyll fluorometry in 24 abundant species to show that—in contrast to presumed strict heterotrophy—large portions of their metabolic needs can be covered through symbiont-supplied autotrophic inputs, even when these are in low abundance and when net photosynthesis remains negative. At the ecosystem level, we find that half of the sponge species on the reefs of Curaçao contribute to 11% of gross primary productivity of the entire benthic ecosystem, ranking them the 4th most important producers after macroalgae, hard corals and gorgonians, and higher than crustose-coralline algae, which are well-known phototrophs. Together with their heterotrophic carbon capturing, we argue that the widespread presence and anticipated contribution of photosymbiotic sponges to coastal ecosystem productivity call for further investigation and for revision of benthic food web models and carbon budgets.

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Shrubs inhibit plant diseases by intercepting light in alpine meadows

Yimin Zhao, Xiaodan Tan, Peng Zhang, Yao Xiao, Xiang Liu, Mu Liu — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Climate change is disproportionately impacting mountain ecosystems, leading to widespread shrub expansion into alpine meadows. Shrub encroachment alters the albedo, carbon budget and warming rate in alpine grasslands, but it remains challenging to predict how shrub encroachment will affect biological interactions, including plant–pathogen interactions. Here, we established a field experiment with four shrub treatments (i.e. shrub encroachment, artificial shrub addition, shrub removal and a natural grassland). Using two treatment combinations with distinct controls, we evaluated shrub effects on pathogen infection in herbaceous plants and examined the underlying regulatory pathways through local herbaceous plant community, microclimate and soils. Shrub encroachment inhibited foliar fungal diseases, especially those caused by necrotrophic pathogens (mainly leaf spot), and these effects primarily derived from reducing light penetration through shrub canopies. Following shrub removal, herbaceous above-ground biomass rebounded, which in turn increased foliar disease pressure. Overall, this study highlights the profound effects of shrub encroachment on alpine grassland ecosystems, underscoring the necessity of considering its complex role in plant-pathogen interactions. These findings have important implications for sustaining grassland biodiversity and productivity and for assessing the ecological outcomes of shrub-removal management in mountain ecosystems.

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Significant resource niche overlap between competing parasitoids does not prevent their successful co‐existence

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Different species that exploit the same resources can sometimes co-exist in the same habitat through resource sharing. For example, if resources are superabundant, then they can be easily partitioned interspecifically among different individuals. However, when resources are scarce, theory predicts that one species will competitively exclude the other if the life cycles of both species overlap spatially and temporally. Here, we studied intrinsic competition between two sympatric gregarious parasitoids, Oomyzus scaposus and O. spiraculus, when developing in the same host individual, that is, larvae of the ladybird Coccinella septempunctata. When hosts were parasitized by one species only, the larvae consumed almost the entire host during their development, leaving nothing available for interspecific competitors. However, in hosts parasitized by both species at different time intervals, resources were partitioned among them, allowing both species to successfully develop and emerge as adults. Nevertheless, O. scaposus was a marginally superior competitor in multiparasitized hosts. This is, as far as we know, the first example of interspecific resource sharing among parasitoids whose larvae consume virtually all host tissues during development. Given that this is an enormous group of insects that exhibit extreme phylogenetic complexity in the expression of traits, these results illustrate how two parasitoid species co-exist on highly limited resources.

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Tree species diversity drives above‐ground carbon sequestration through light‐related trait shifts

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Functional traits can vary in response to tree species mixing, which in turn might influence biomass production and, consequently, carbon (C) sequestration in diverse forests. However, evidence for consistent broad-scale patterns in tree trait responses, particularly regarding trait identity and their contribution to above-ground biomass outcomes, remains limited. Using data from even-aged forest stands in 11 tree diversity experiments in Europe and Brazil, encompassing 40 tree species, we estimated the influence of species mixing on above-ground biomass components (woody, litterfall and understory biomass), as well as effects of mixing on plasticity-driven changes in species- and community-level functional traits. At the community level, specific leaf area (SLA) and leaf area index (LAI) were higher in mixtures than expected values based on monocultures, while leaf nitrogen per area decreased, and leaf nitrogen per mass remained stable. SLA increases were primarily due to the response of less dominant tree species. Woody and litterfall biomass increased in mixtures, whereas understory biomass remained unchanged. At the species level, diversity-driven plastic changes were observed in multiple traits, but only SLA showed a consistent shift across species. Tree diversity effects on above-ground biomass were influenced by both functional diversity and diversity-driven trait shifts, where increased SLA and LAI enhanced woody biomass accumulation, while higher LAI in diverse stands reduced understory biomass. Together, these results show that tree species mixing alters canopy structure and light-related traits, with shifts in SLA and LAI constituting key pathways through which mixed forests accumulate more woody biomass.

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Mycorrhizal symbiosis and environmental conditions shape understory herb diversity in a large temperate forest region

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Understorey herbaceous plants are a vital component of forest biodiversity in temperate forests. However, the mechanisms underlying their community assembly and species coexistence remain poorly understood. This study investigates how environmental conditions and mycorrhizal symbiosis across different forest strata influence herb diversity in a temperate forest region. This study used data from 437 temperate forest plots spanning environmental gradients. Within the Hill–Chao framework, we calculated herb species and phylogenetic diversity indices. We then explored the specific pathways through which environmental factors and mycorrhizal associations influence herb diversity. Herb species and phylogenetic diversity were positively correlated and showed largely consistent responses to mycorrhizal symbiosis. Herb community mycorrhization promoted herb diversity. Greater ectomycorrhizal (EcM) tree dominance significantly reduced herb diversity. Notably, mixed-mycorrhizal tree communities supported the highest levels of herb diversity. Climate, particularly precipitation, shaped the spatial distribution of mycorrhizal status and types, thereby indirectly influencing herb diversity. Soil total nitrogen affected herb diversity indirectly through its influence on EcM tree dominance. By disentangling the complex relationships between mycorrhizal symbiosis across forest strata and herb diversity along ecological gradients, this study contributes to a better understanding of species coexistence in forest ecosystems.

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Fertilization influences overyielding through dominance of species with high specific leaf area in young tree mixtures

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

In the context of anthropogenic eutrophication of the biosphere, understanding the impact of nutrient addition on plant diversity–productivity relationships remains a major challenge. In particular, the indirect effect of nutrient addition on productivity in tree mixtures via changes in the functional structure of tree communities has never been experimentally quantified and may play an important role in mediating diversity–productivity relationships. Here, we present results from young experimental tree communities 4 years after planting, including monocultures and two- and four-species mixtures of six European species (Acer platanoides, Betula pendula, Larix decidua, Picea abies, Pinus sylvestris and Quercus robur) with or without 4 years of mineral fertilizer addition. Using a response-effect trait framework that links plant functional traits with ecosystem processes, we specifically examined how functional diversity (FD) and community weighted means (CWM) of tree height (H) and specific leaf area (SLA) were influenced by fertilization and to what extent they mediated the fertilization effect on above-ground productivity in woody tissues. The overall fertilization effect on the degree of community-level overyielding was marginally positive, yet the influence of fertilization varied significantly depending on species composition. Fertilization affected community functional trait structure primarily by increasing CWM of SLA through dominance of species with high SLA, rather than through intraspecific trait variability. Interestingly, the fertilization-induced change in CWM of SLA reduced community-level overyielding. Irrespective of fertilization, CWM of H and SLA influenced community-level overyielding, while FD had no significant effects. Our results indicate that changes in nutrient availability can influence the magnitude of overyielding indirectly through dominance of species with high SLA in young tree communities. This result improves our understanding of the context dependency of diversity–productivity relationships, which strongly depends on nutrient availability influencing the competitive relationships among tree species. The occurrence of such effects early after tree planting could potentially produce long-term consequences for tree community composition, and even more so in naturally regenerating forests with less control on tree species selection.

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要旨

人為的な影響により生物圏の富栄養化が加速する中、植物の多様性-生産性関係に対する影響を理解することが重要な課題となっている。特に、栄養塩添加が樹木群集の機能構造の変化を介して、混交林の生産性に間接的な影響を及ぼす可能性がある。しかし、こうした間接効果が多様性–生産性関係に果たす役割はこれまで実験的に定量化されてこなかった。本研究では、植栽後4年の幼齢樹木群集における実験結果を報告する。実験では、6種のヨーロッパ原産樹種(ヨーロッパカエデ　Acer platanoides,、ヨーロッパシラカンバ　Betula pendula、ヨーロッパカラマツ　Larix decidua、ヨーロッパトウヒ　Picea abies、ヨーロッパアカマツ　Pinus sylvestris、ヨーロッパナラ　Quercus robur)による単一植栽区および2種・4種混合植栽区を設定した。それぞれにおいて、4年間にわたり無機肥料を添加した施肥区と、無施肥区を設けた。機能形質と生態系プロセスの関係を明らかにするため、応答-効果形質フレームワークを用いて解析を行った。具体的には、施肥に対する樹高(H)および比葉面積(SLA)の機能的多様性(FD)と群集加重平均(CWM)の応答を介した、群集レベルの地上木部生産性への影響を検証した。群集レベルの過剰収量(単一植栽と比較した混合植栽の相対的生産性)に対する施肥の効果は、平均的にはわずかに正の影響を示したものの、その大きさは樹種構成によって大きく異なっていた。群集の機能的形質構造に対する施肥の影響は、種内の形質変動ではなく、高SLA種の優占によってSLAのCWMが増加することによって主に生じた。興味深いことに、施肥によるSLAのCWMの上昇は、群集レベルの過剰収量を減少させる傾向を示した。施肥の有無にかかわらず、HとSLAのCWMは過剰収量に影響した一方、FDは有意な効果を示さなかった。以上の結果から、栄養塩の可給性の変化が、高SLA種の優占を通じて、幼齢樹木群集の過剰収量の大きさに間接的に影響を与えることが示された。この知見は、多様性–生産性関係の状況依存性に関する理解を深めるものであり、とりわけ、可給性の高低が樹種間の競争関係を左右することの重要性を示している。このような植栽後早期の影響は、長期にわたって樹木群集の構成に影響を及ぼす可能性があり、樹種選択の自由度が限られる天然更新林においては、より長期的かつ顕著な影響が及ぶ可能性がある。

Can manipulative parasites modify host‐mediated trophic effects? Experimental evidence from Schistocephalus solidus and three‐spined sticklebacks

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Parasites can alter host traits, thereby reshaping host interactions and modifying density- and trait-mediated effects in trophic cascades. But despite increasing research in parasite ecology, the cascading effects of parasitism from individual hosts to population and community levels remain underexplored. Here, we aim to fill this gap by conducting a large-scale mesocosm experiment replicating key phases of the parasite's development to test our hypothesis that the trophically transmitted tapeworm Schistocephalus solidus weakens stickleback-driven trophic cascades by altering host performance and feeding behaviour. We quantified parasite effects on three-spined sticklebacks (Gasterosteus aculeatus) and their prey communities. Schistocephalus solidus infection reduces stickleback body condition and shifts zooplankton biomass, transiently dampening the likelihood and strength of stickleback-driven trophic cascades at specific time points of infection. Using structural equation models, we show that parasite-driven trait-mediated indirect effects (TMIEs) are equivalent to density-mediated indirect effects (DMIEs) on trophic cascades. Strikingly, our results suggest that infection increases per capita zooplankton consumption of fish and amplifies parasite-driven TMIEs, counterbalancing the effects of DMIEs due to fish mortality. Overall, our findings highlight the complexity of host–parasite interactions and their community and ecosystem-level consequences.

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Root exudates mediate microorganisms to improve rhizosphere nutrient availability and crop productivity under straw mulching and slow‐release nitrogen fertilizer

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Root exudates play a key role as signals and nutrients in mediating plant–microbe communication. However, critical knowledge gaps remain regarding how root exudates mediate soil–microbe–plant interactions to regulate crop yield under long-term straw mulching combined with fertilization. Therefore, we conducted a 3-year field trial integrating straw management (straw mulch (S) versus removal (S₀)) with different nitrogen fertilizer types (no fertilizer (W), conventional nitrogen fertilizer (U), and slow-release nitrogen fertilizer (RU)), employing integrated metabolomic and microbiome analyses to evaluate how root exudates affect microbial communities and may contribute to improved rhizosphere soil nutrients and crop productivity. Using the S₀W as a control (yield: 357.6 kg ha⁻¹) to highlight the effects of management practices, the results showed that both the SU and SRU treatments significantly increased crop yields, reaching 1105.1 and 1631.8 kg ha⁻¹, respectively. Compared with S₀W, the SU and SRU treatments also significantly enhanced soil organic carbon content by 43.3% and 54.4%, respectively. The SRU treatment demonstrated the most pronounced improvements in total nitrogen and total phosphorus, with increases of 28.9% and 18.5%, respectively. Furthermore, the SRU treatment significantly increased the relative abundance of microorganisms such as Glomeromycota and Cladosporiaceae, as well as key lipid and organic acid metabolites in root exudates. Weighted correlation network analysis and Mantel tests revealed that putatively annotated metabolites were significantly correlated with both soil nutrient content and the enrichment of key microbial taxa (Acidobacteriota and Cladosporiaceae). Subsequent partial least squares path modelling further demonstrated that these interactions were significantly linked to improved soil nutrient status and increased crop yield. In summary, this study provides important insights for ameliorating degraded soils and optimizing extensive management practices.

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摘要

根系分泌物作为信号物质和养分，在调节植物-微生物交流中起着关键作用。然而，关于长期秸秆覆盖结合施肥下，根际分泌物如何介导土壤-微生物-植物互作以调节作物产量，仍存在关键的知识空白为此，我们进行了一项为期3年的田间试验，将秸秆管理(秸秆覆盖(S)与秸秆清除(S₀))与不同氮肥类型(不施肥(W)、常规氮肥(U)和缓释氮肥(RU))相结合，采用代谢组学和微生物组学联合分析方法，评估根系分泌物影响微生物群落进而可能促进根际土壤养分改善和作物生产力提升的作用机制。以S₀W处理作为对照(产量:357.6 kg ha⁻¹)来凸显管理措施的效果，结果表明，SU和SRU处理均显著提高了作物产量，分别达到1105.1和1631.8 kg ha⁻¹。与S₀W相比，SU和SRU处理还分别显著提升了土壤有机碳含量43.3%和54.4%。SRU处理在提高全氮和全磷方面效果最为显著，分别增加了28.9%和18.5%。此外，SRU处理显著增加了球囊菌门(Glomeromycota)和枝孢霉科(Cladosporiaceae)等微生物的相对丰度，以及根系分泌物中脂质和有机酸代谢物的含量。加权基因共表达网络分析和Mantel检验显示，推定注释的根系代谢物与土壤养分含量及关键微生物类群(酸杆菌门(Acidobacteriota)和枝孢霉科(Cladosporiaceae))的富集显著相关。随后的偏最小二乘路径模型进一步证明，这些相互作用与土壤养分状况的改善和作物产量的提高显著相关。综上所述，本研究为改良退化土壤和优化农田管理实践提供了重要的见解。

Leaf photoprotection and water relations traits reveal novel axes of coordination and trade‐offs in leaf function

Bailey H. McNichol, Ran Wang, John A. Gamon, Sabrina E. Russo — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Plants can express considerable plasticity in leaf functional traits, but that plasticity may be constrained by coordination and trade-offs among multiple functions. The leaf economics spectrum (LES) describes a well-supported trade-off between durability versus productivity but does not capture all dimensions of leaf functional responses to environmental variation. We hypothesized that traits related to photoprotection, desiccation tolerance, and water-use efficiency (WUE) would occupy axes distinct from, and potentially orthogonal to, the LES, and that species would differ in how they resolve multifunctional trade-offs along environmental gradients, influencing the strength of within- versus between-species trait relationships. We tested these hypotheses by analysing 11 leaf traits on 219 individuals of 16 woody species in a 20.2-ha temperate woodland plot spanning a topography-driven desiccation gradient in the North American Great Plains. Using multivariate ordinations, environmental vector fitting, and complementary bivariate correlation and standardized major axis analyses, we quantified axes of trait coordination and compared relationships within and between species. More productive leaves were less desiccation tolerant, durable, and water-use efficient, invested less in carotenoid-related photoprotection, and occurred in more mesic topographic positions. Ordinations revealed novel functional relationships and trade-offs: WUE was coordinated with carotenoid-related photoprotection, with more water-use efficient leaves investing more in photoprotection and less in chlorophylls relative to carotenoids, while desiccation tolerance aligned with durability and traded off with productivity traits. Within-species analyses confirmed strong, consistent relationships among LES traits and desiccation tolerance, whereas relationships involving WUE and photoprotection—reflecting more dynamic physiological processes—varied among species, producing weak between-species correlations. Together, these patterns indicate that WUE and photoprotection are coordinated along an axis approximately orthogonal to the LES, capturing covariation among dynamic physiological rather than structural functions. Supporting the idea that how individuals resolve functional trade-offs along environmental gradients shapes between-species trait relationships, our study not only expands the leaf economics framework but also reconceptualizes it in relation to critical trade-offs involving carotenoid-related photoprotection, desiccation tolerance, and WUE. By identifying new dimensions of trait relationships, our study advances functional ecology by highlighting leaf phenotypic variation along gradients as an integrated expression of multiple interacting functions.

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Hotspots on cold mountains: Hot flowers as pollinator refuges in mountain ecosystems

Joshua M. Coates, Maldwyn J. Evans, Ben C. Scheele, Saul A. Cunningham — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Mountain environments constrain the activity of ectothermic insects. Yet, fine-scale thermal refuges can buffer these thermal constraints, helping insects remain active in cold conditions. Previous work has demonstrated that some flowers experience substantial floral warming, with temperatures exceeding ambient air temperature. This raises the question: do flowers offer thermal benefits that influence insect activity at the plant–insect community scale? To test whether subalpine and alpine flowers function as warm microhabitats for insect pollinators, we quantified flower temperatures across a diverse plant community in the Australian alps and examined the relationship between flower temperature and the frequency of flower–insect interactions. We found that most plant species exhibited floral temperatures above ambient air temperatures, with the difference sometimes exceeding 10°C. Environmental conditions, especially UV irradiance index, were associated with enhanced warming, while increased relative humidity was associated with lower flower temperatures. Among the floral traits we examined, shape was the strongest predictor of warming, with globular, cup- and star-shaped flowers warming most strongly, whereas tubular and bell-shaped flowers only warmed slightly above air temperature. Insect body temperature was also typically warmer than floral tissues. Notably, we found that when ambient conditions were cool, warm flowers received significantly more insect visits, especially from Diptera. This effect weakened as ambient temperature increased. Our results indicate that some flowers may provide insects with a thermal reward when ambient conditions are otherwise activity limiting. Our results offer community level insights suggesting that naturally warmer flowers attract more insect visitors during cold conditions, thereby connecting ambient temperature, floral microhabitat and insect activity across a mountain plant–insect assemblage.

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From pollen provision to pollinator: Species‐specific sterol assimilation by wild bees in urban landscapes

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Human-driven landscape change, particularly urbanization, is reshaping pollinator communities, yet the functional traits that mediate species persistence remain poorly understood. Dietary specialization is commonly used to predict species vulnerability. However, conventional measures based on taxonomic plant host breadth may not reflect pollinators' actual nutritional needs, especially in cities where exotic and native plants coexist. Because insects cannot synthesize sterols de novo, they must obtain these essential lipids from their diet, making sterol requirements a critical and overlooked axis for understanding pollinator persistence. Here, we analysed 22 sterols in 274 pollen provision samples and 1267 bee individuals from four common wild bee species, ranging from specialists to generalists, sampled following urban intensity gradients across five European cities. We reveal that regardless of host–plant specialization levels, all species relied on a shared set of four abundant sterols, commonly found in plant pollen, suggesting that sterol generalization may contribute to their urban persistence. Nonetheless, the full sterol profiles, both composition and concentration, varied between the bees' bodies and their pollen provisions, as well as across species and cities. This suggests that wild bees do not simply mirror their diet, but rather assimilate sterols in a species-specific manner. The most specialized bee, Chelostoma florisomne, showed more uniform sterol use and was often absent in highly urbanized areas, possibly due to frequent mowing of its main host, Ranunculus flowers. These findings underscore the limitations of using solely on plant host composition in pollen for predicting pollinator responses to urban intensity and highlight the importance of nutritional needs, such as sterols, in shaping ecological niches and guiding conservation strategies.

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摘要

人类活动引起的景观变化，尤其是城市化进程，正在重塑传粉者群落结构。然而，目前仍不清楚哪些功能性状能够影响物种在城市环境中的持续生存。食性专化程度常被用作预测物种脆弱性的指标。然而，传统的测量方法，例如基于食物来源广度(所利用植物种类数量)的指标，可能无法反映传粉者真实的营养需求，特别是在本地与外来植物共存的复杂城市环境中。昆虫无法自主合成甾醇，必须完全依赖食物来获取这些必需的脂类物质。因此，甾醇需求是传粉者能否在城市中长期生存的关键因素，但该因素在以往研究中长期被忽视。本研究分析了欧洲五个城市，沿城市化强度梯度采集的四种常见野生蜂(食性从高度专化到广食性不等)的274份巢管花粉样本及1267个巢管蜂样本中的22种甾醇。无论食性专化程度如何，我们发现这四种蜂类在很大程度上依赖于四种丰度较高的甾醇。这些甾醇在植物花粉中非常普遍，这表明对常见甾醇的广泛利用能力可能有助于这些蜂类在城市环境中持续存在。然而，我们也观察到，所有甾醇的组成和浓度在巢花粉与蜂体组织之间存在差异，并且在不同蜂种和不同城市之间也存在差异。这表明野生蜂对甾醇的吸收和利用具有物种特异性。专化性最强的蜂Chelostoma florisomne表现出更单一的甾醇利用模式，这种蜂在高度城市化地区往往缺失，这可能与其唯一食物来源—毛茛属(Ranunculus)植物的花朵在城市绿地中被频繁修剪有关。这些结果表明，仅依赖花粉中的植物组成来预测传粉者对城市化强度的响应存在一定的局限性。同时，本研究也强调了营养需求(如甾醇)在塑造传粉者生态位及制定传粉者保护策略中的重要作用。

Resum

Els canvis d’usos del sòl, en particular la urbanització, estan reestructurant les comunitats de pol·linitzadors, i, no obstant això, els trets funcionals que influeixen en la persistència de les espècies de pol·linitzadors romanen poc estudiats. El grau d’especialització de la dieta és una mètrica emprada habitualment per a predir la vulnerabilitat de les espècies. Tanmateix, les mesures convencionals, com les basades en l’amplitud de la dieta (nombre d’espècies de plantes usades), poden no reflectir les necessitats nutricionals dels pol·linitzadors, en particular en ciutats, on coexisteixen tant espècies exòtiques com autòctones de plantes. Atès que els insectes no poden sintetitzar esterols de zero, depenen de la seva dieta per adquirir aquests lípids essencials. Consegüentment, les necessitats d’esterols representen un eix crític, i malgrat això, sovint passat per alt, per entendre la persistència dels pol·linitzadors. En aquest estudi, hem analitzat 22 tipus d’esterols en 274 provisions de pol·len (de les larves d’abelles) i en 1,267 individus (els seus teixits corporals) pertanyents a quatre espècies comunes d’abelles silvestres. Aquestes quatre espècies inclouen tant espècies generalistes com especialistes, i van ser mostrejades seguint gradients d’intensitat urbana en cinc ciutats europees. Independentment del grau d’especialització i amplitud de la dieta, hem trobat que les quatre espècies d’abelles depenen en gran part de quatre esterols abundants, els quals són molt comuns en el pol·len de les plantes, el que suggereix que les preferències generalistes d’esterols poden contribuir en la seva persistència en ambients urbans. No obstant això, hem observat que la composició i concentració de tots els esterols varia entre les provisions de pol·len i els teixits de les abelles, així com entre espècies i ciutats. Això suggereix que les abelles silvestres assimilen esterols de manera específica per a cada espècie. L’abella més especialista, Chelostoma florisomne, que ha mostrat un ús en els esterols més uniforme, es troba sovint absent en àrees altament urbanitzades, possiblement a causa de la sega freqüent de la seva única font d’aliment, les flors del gènere Ranunculus. Aquests resultats subratllen les limitacions d'utilitzar exclusivament la composició de plantes en el pol·len per predir les respostes dels pol·linitzadors a la intensitat urbana i posen en relleu la importància de les necessitats nutricionals, com els esterols, en la configuració dels nínxols ecològics i en la guia d'estratègies de conservació.

Resumen

Los cambios de usos del suelo, en particular la urbanización, están reestructurando las comunidades de polinizadores, y, sin embargo, los disparos funcionales que influyen en la persistencia de las especies de polinizadores permanecen poco estudiados. El grado de especialización de la dieta es una métrica habitualmente empleada para predecir la vulnerabilidad de las especies. Aun así, las medidas convencionales, como las basadas en la amplitud de la dieta (número de especies de plantas recolectadas en el polen), pueden no reflejar las necesidades nutricionales de los polinizadores, en particular en ciudades, donde coexisten especies exóticas y autóctonas de plantas. Dado que los insectos no pueden sintetizar esteroles de cero, dependen de su dieta para obtener estos lípidos esenciales. Consiguientemente, las necesidades de esteroles representan un eje crítico, y a pesar de esto, a menudo pasado por alto, para entender la persistencia de los polinizadores. En este estudio, hemos analizado 22 tipos de esteroles en 274 provisiones de polen (para las larvas) y en 1,267 individuos pertenecientes a cuatro especies comunes de abejas silvestres. Estas cuatro especies incluyen tanto especies generalistas como especialistas, y fueron muestreadas siguiendo gradientes de intensidad urbana en cinco ciudades europeas. Independientemente del grado de especialización y la amplitud de la dieta, hemos encontrado que las cuatro especies de abejas dependen en gran medida de cuatro esteroles abundantes, muy comunes en el polen de las plantas, lo que sugiere que las preferencias generalistas de esteroles pueden contribuir a su persistencia en ambientes urbanos. Sin embargo, hemos observado que la composición y la concentración de todos los esteroles varían tanto entre las provisiones de polen y los tejidos de las abejas como entre especies y ciudades. Esto sugiere que las abejas silvestres asimilan esteroles de manera específica para cada especie. La abeja más especialista, Chelostoma florisomne, que ha mostrado un uso de los esteroles más uniforme, está ausente en áreas altamente urbanizadas, posiblemente debido a la siega frecuente de su única fuente de alimento, las flores del género Ranunculus. Estos resultados subrayan las limitaciones de utilizar exclusivamente la composición de plantas en el polen para predecir las respuestas de los polinizadores a la intensidad urbana y ponen de relieve la importancia de las necesidades nutricionales, como los esteroles, en la configuración de los nichos ecológicos y en la guía de estrategias de conservación.

Zusammenfassung

Vom Menschen verursachte Landschaftsveränderungen, insbesondere die Urbanisierung, verändern die Bestäubergemeinschaften. Doch die funktionellen Eigenschaften, die das Fortbestehen der Arten beeinflussen, sind noch immer kaum verstanden. Dabei wird häufig die Spezialisierung der Ernährung zur Vorhersage der Gefährdung von Arten herangezogen. Herkömmliche Messungen, die auf der taxonomischen Zusammensetzung der Wirtspflanzen basieren, spiegeln jedoch möglicherweise nicht den tatsächlichen Nährstoffbedarf der Bestäuber wider, vor allem in Städten, wo exotische und einheimische Pflanzen vorkommen. Da Insekten Sterole nicht selber synthetisieren können, müssen sie diese essenziellen Lipide über ihre Nahrung aufnehmen. Dadurch wird der Sterolbedarf zu einem entscheidenden und oft übersehenen Faktor für das Verständnis des Fortbestands von Bestäubern. Hier haben wir 22 Sterole in 274 Pollenproben und in 1.267 Bienenindividuen (d.h. von ihren Körpern) von vier verbreiteten Wildbienenarten analysiert, die von Spezialisten bis zu Generalisten reichen und entlang städtischer Intensitätsgradienten in fünf europäischen Städten gesammelt wurden. Wir zeigen, dass unabhängig vom Grad der Spezialisierung alle Arten auf vier häufig vorkommende Sterole zurückgreifen, die üblicherweise in Pflanzenpollen zu finden sind. Das deutet darauf hin, dass die Sterolgeneralisierung zu ihrem Fortbestand in städtischen Gebieten beiträgt. Dennoch variierten die vollständigen Sterolprofile, sowohl hinsichtlich der Zusammensetzung als auch der Konzentration, zwischen den Körpern der Bienen und ihren Pollenvorräten sowie zwischen den Arten und Städten. Dies deutet darauf hin, dass Wildbienen die Sterole aus ihrer Nahrung nicht einfach unverändert übernehmen, sondern sie auf artspezifische Weise assimilieren. Die am stärksten spezialisierte Biene, Chelostoma florisomne, zeigte eine einheitlichere Sterolnutzung und war in stark urbanisierten Gebieten oft nicht anzutreffen, möglicherweise aufgrund des Verschwindens ihrer einzigen Pflanzenwirte, Ranunculus spp. Diese Ergebnisse unterstreichen die Grenzen der ausschließlichen Verwendung der taxonomischen Zusammensetzung der Wirtspflanzen zur Vorhersage der Reaktionen von Bestäubern auf die städtische Intensität. Zusätzlich heben sie die Bedeutung von Ernährungsbedürfnissen, wie z. B. Sterolen, für die Gestaltung ökologischer Nischen und die Ausrichtung von Schutzstrategien hervor.

Riassunto

I cambiamenti nell'uso del suolo, in particolare l'urbanizzazione, stanno ristrutturando le comunità di impollinatori, ma le caratteristiche funzionali che determinano la persistenza delle specie di impollinatori rimangono poco studiate. Il grado di specializzazione alimentare è un parametro comunemente utilizzato per prevedere la grado di vulnerabilità delle specie. Tuttavia, le misure comunemente utilizzate, come quelle basate sull'ampiezza della dieta (numero di specie vegetali utilizzate), potrebbero non riflettere i requisiti nutrizionali degli impollinatori, in particolare nelle città, dove coesistono specie esotiche e autoctone. Poiché gli insetti non sono in grado di sintetizzare gli steroli, essi dipendono dalle piante di cui si nutrono per acquisire questi lipidi essenziali. Di conseguenza, il fabbisogno di steroli rappresenta un aspetto critico, ma spesso trascurato, per comprendere la persistenza degli impollinatori. In questo studio, abbiamo analizzato 22 tipi di steroli in 274 provviste di polline destinate alle larve e 1.267 individui di api selvatiche appartenenti a quattro specie comuni. Queste quattro specie includono sia generalisti che specialisti e sono state campionate lungo gradienti di intensità urbana in cinque città europee. Indipendentemente dal grado di specializzazione delle specie di api e dall'ampiezza della loro dieta, abbiamo scoperto che le quattro specie di api dipendono fortemente da quattro steroli abbondanti, molto comuni nel polline delle piante. Questo suggerisce che le preferenze generaliste a livello degli steroli possano contribuire alla persistenza delle specie di api studiate negli ambienti urbani. Tuttavia, abbiamo osservato che la composizione e la concentrazione di tutti gli steroli variano tra le provviste di polline e i tessuti delle api adulte, nonché tra le specie e le città. Ciò suggerisce che le diverse specie di api selvatiche assimilano gli steroli in modo specifico. La specie con una dieta più specializzata, Chelostoma florisomne, ha mostrato un uso più uniforme degli steroli nelle aree altamente urbanizzate, da dove spesso è assente, forse a causa del frequente sfalcio della sua unica fonte di cibo, i fiori del genere Ranunculus. Questi risultati evidenziano i limiti dell'utilizzo esclusivo della composizione delle piante nel polline (dieta delle api) per prevedere le risposte degli impollinatori all'intensità urbana e sottolineano l'importanza dei requisiti nutrizionali dei fiori, come gli steroli, nel plasmare le nicchie ecologiche delle specie di api e guidare le strategie di conservazione.

Résumé

Les changements dans l'utilisation des sols, en particulier l'urbanisation, restructurent les communautés de pollinisateurs, mais les facteurs fonctionnels qui influencent la persistance des espèces pollinisatrices restent peu étudiés. Le degré de spécialisation alimentaire est un indicateur couramment utilisé pour prédire la vulnérabilité des espèces. Cependant, les mesures conventionnelles, telles que celles basées sur la diversité alimentaire (nombre d'espèces végétales butinées), peuvent ne pas refléter les besoins nutritionnels des pollinisateurs, en particulier dans les villes, où coexistent des espèces végétales exotiques et indigènes. Comme les insectes ne peuvent pas synthétiser de stérols naturellement, ils dépendent de leur régime alimentaire pour obtenir ces lipides essentiels. Par conséquent, les besoins en stérols représentent un axe critique, mais souvent négligé, pour comprendre la persistance des pollinisateurs. Dans cette étude, nous avons analysé 22 types de stérols dans 274 réserves de pollen (pour les larves) et dans 1 267 individus appartenant à quatre espèces communes d'abeilles sauvages. Ces quatre espèces comprennent à la fois des espèces généralistes et spécialisées, et ont été échantillonnées selon des gradients d'intensité urbaine dans cinq villes européennes. Indépendamment du degré de spécialisation et de la diversité de leur régime alimentaire, nous avons constaté que les quatre espèces d'abeilles dépendent largement de quatre stérols abondants, très courants dans le pollen des plantes, ce qui suggère que leurs préférences généralistes en matière de stérols peuvent contribuer à leur persistance dans les environnements urbains. Cependant, nous avons observé que la composition et la concentration de tous les stérols varient autant entre les réserves de pollen et les tissus des abeilles qu'entre les espèces et les villes. Cela suggère que les abeilles sauvages assimilent les stérols de manière spécifique à chaque espèce. L'abeille la plus spécialisée, Chelostoma florisomne, qui a montré une utilisation plus uniforme des stérols, est absente des zones fortement urbanisées, peut-être en raison de la fauche fréquente de sa seule source de nourriture, les fleurs du genre Ranunculus. Ces résultats soulignent les limites de l'utilisation exclusive de la composition des plantes dans le pollen pour prédire les réponses des pollinisateurs à l'intensité urbaine et mettent en évidence l'importance des besoins nutritionnels, tels que les stérols, dans la configuration des niches écologiques et l'orientation des stratégies de conservation.

Functional divergence drives the prevalence of low‐abundance species in bat assemblages

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Ecological communities are structured by a few common species, while most occur at low abundance. Understanding the drivers of this widespread pattern raises fundamental questions about community assembly rules and is important for applied ecology for identifying conservation targets. We used assemblages of phyllostomid bats to answer the following questions: (i) Does a higher divergence of morphological traits and functional hypervolume from the assemblage explain the prevalence of low-abundance species? (ii) What is the relative importance of single functional traits and functional hypervolume divergence to explain such patterns? We sampled phyllostomid bats across an urban–rural landscape and estimated species abundance, measured key morphological traits, and calculated functional hypervolumes. We then applied a Bayesian causal inference framework to identify the drivers of abundance. The divergence of functional hypervolume, flight performance, and food acquisition traits had a negative impact on the abundance of the species. This pattern holds whether assessing aggregated species abundance or when considering spatiotemporal variation in assemblage structure, implying that low-abundance species had functional hypervolumes and morphological traits more divergent from the assemblage average. Species ranked at the quantile intervals 0%–25% and 25%–50% of abundance occupied hypervolumes 45.9% and 46.8% more divergent compared to species ranked at Q 75%–100%. Similarly, the species at Q 0%–25% and 25%–50% exhibited a 59.5% greater divergence in morphological traits compared to common species. Such divergence on specific traits and intraspecific functional space from the assemblage centroid can result in a substantial reduction (13%–57%) in species abundance. Our results indicate that low-abundance species are linked to their trait and hypervolume functional divergence. We propose that the position of the species in the functional space and the divergence of sensory- and vagility-related traits are factors that determine the structure of bat communities, which denotes niche axes that have likely been narrowed at the current human-dominated habitat. Our findings emphasize the importance of low-abundance species, as they occupy unique ecological niches and likely contribute to specific ecosystem processes.

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Pollinator diversity and host specificity in threatened Encephalartos cycads and their implications for co‐extinction and species recovery

Paul D. Janse van Rensburg, Terence N. Suinyuy, John S. Donaldson — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

The highly threatened African cycad genus Encephalartos faces severe threats such as habitat loss and poaching. In addition, the lack of sexual recruitment due to the absence of pollinators (pollinator collapse) has emerged as another major threat. Experimental studies have identified three key Encephalartos pollinator groups: Porthetes (Coleoptera: Curculionidae), undescribed erotylid species (Coleoptera: Erotylidae) and Metacucujus (Coleoptera: Boganiidae). This study investigates the diversity and host specificity of Encephalartos pollinators to determine their vulnerability to collapse and potential for recovery. Across 28 Encephalartos species in southern and eastern Africa, we recorded 39 putative pollinator taxa, most showing high host specificity, with 19 species occurring on a single host. To identify potential traits affecting pollinator host specificity for further study, we analysed the influence of host phylogeny, cone volatile profiles, cone colour and cone phenology using distance-based redundancy analysis. Host relatedness and cone volatile emissions explained the largest proportion of variation in pollinator assemblages, while cone colour and phenology contributed comparatively less. These relationships should be interpreted cautiously since analyses were based on total cone volatile composition and human-perceived cone colour, and may not directly reflect the specific compounds or perceptual cues used by pollinators. Records of pollinators visiting novel host plants in cultivation suggest that host use may sometimes extend beyond observed wild associations, potentially reflecting pre-adapted recognition mechanisms linked to cone traits similar to those of their wild hosts, or previously existing host associations that have been lost in the wild. These possibilities require further behavioural and ecological testing. Our findings confirm reports of pollinator collapse in at least 13 Encephalartos species, emphasizing the urgent need to consider pollinators in cycad conservation strategies. Future research should prioritize ecological and behavioural studies of cue perception and attraction, refinement of pollinator taxonomy, and evaluation of whether ecologically compatible pollinator species could be used to restore pollination in Encephalartos species where pollinator mutualists have been lost.

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Artificial light at night and invasive signal crayfish alter aquatic‐terrestrial food webs

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Resource flows across aquatic-terrestrial boundaries are increasingly affected by multiple stressors, such as artificial light at night (ALAN) and aquatic invasive species, which can alter the availability of resources for consumers. However, how these stressors, individually or in combination, affect the diets of aquatic and terrestrial consumers remains poorly understood. We conducted a 6-week mesocosm experiment in Southwest Germany using 16 artificial streams with adjacent riparian areas, assigned to one of four treatments: control, ALAN, signal crayfish presence and their combination. We used stable isotope ratios of carbon and nitrogen to assess the diet and trophic niche width of the riparian spider Tetragnatha extensa and the invasive signal crayfish Pacifastacus leniusculus. Stable isotope mixing model shows that aquatic sources comprised 56% (95% HDI: 40%–64%) of T. extensa's diet in the control, 57% (49%–73%) under ALAN, 64% (49%–79%) under crayfish and 58% (35%–79%) under combined ALAN and crayfish. The normalized median niche width of T. extensa increased under ALAN by 14% (95% CI: 6%–24%) and combined ALAN and crayfish treatment by 13% (6%–23%) compared to 6% (3%–10%) in the control, indicating greater dietary diversity, while crayfish-only was similar at 7% (3%–12%). This pattern reflects shifts in resource availability to T. extensa under both individual and combined ALAN exposure. The signal crayfish showed a similar response, with diet consisting of roughly half of the combined Chironomidae–Gammaridae prey source in the absence of ALAN and increasing to about three quarters under ALAN treatment, with a 6.4% (3.6%–10.1%) wider isotopic niche width under ALAN conditions. Overall, these shifts, driven by ALAN despite the presence of signal crayfish, highlight how multiple stressors can reshape resource flows across linked aquatic-terrestrial ecosystems, with implications for riparian food-web dynamics and biodiversity.

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Allochthonous chemical cues drive predation by a top carnivore

Ryan P. Ferrer, Richard K. Zimmer — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Identifying the mechanisms by which mobile predators detect and select prey remains a central challenge in sensory biology and functional ecology. This study provides the first direct evidence that chemical cues associated with allochthonous organic matter (e.g. leaf litter) can restructure chemosensory environments and fundamentally alter consumer-resource dynamics. Using a combination of remote behavioural observations, field experiments with free-ranging animals and predator inclusion/exclusion cage treatments, we examined how external organic inputs indirectly modify trophic interactions within a residential stream community. As top predators, newts (Taricha torosa) exhibited a strong chemical attraction to patches containing terrestrially derived plant material, whereas natural substrates composed of rock cobble were used at disproportionately lower rates than predicted by availability. In fact, upon detecting waterborne cues from leaf litter, individuals abandoned cobble and moved upstream to colonize chemically enriched areas. Predator attraction was driven by compounds leaching from allochthonous plant matter, not by cues from native insect larval prey. Even when prey densities were standardized experimentally across habitat types, predation rates by newts were significantly higher in leaf litter than in other substrates. Such chemically mediated shifts in behaviour suggest a general mechanism by which spatial subsidies of organic matter can restructure predator–prey dynamics. By redirecting top carnivore attention and effort, infochemicals derived from non-native sources may play a fundamental role in shaping community organization and regulating energy flow across ecosystem boundaries.

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Anthropogenic nitrogen addition interrupts seasonal connectivity and structures of plant–pollinator networks

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Ecological communities are stressed by rapid and complex anthropogenic changes, threatening the persistence of biotic interactions and ecosystem functioning. Plant–pollinator communities, for instance, undergo structural transformations as a result of land-use change, species invasion and climate change. By experimentally investigating changes of interaction networks over time, caused by anthropogenic disturbances, we will be able to better understand the underlying ecology and predict our impact on communities. Here, we used a long-term community field experiment involving nitrogen (N) addition to investigate the impacts of anthropogenic N enrichment on seasonal dynamics of a N-limited, fast-changing ecosystem: alpine meadows on the Tibetan Plateau. Given the brief flowering season and pollinators' phenophase of alpine meadows, we were particularly interested in understanding how N-induced changes in flowering communities alter plant–pollinator interactions assembly and disassembly over the season, which ultimately shapes network structure and defines ecological resilience of communities. We found that N-induced declines in floral abundance and richness resulted in an increase in pollinator species turnover over the season. This, in turn, affected natural interaction rewiring processes among temporally persistent species, suggesting a markedly lower seasonal connectivity and persistence of plant–pollinator interactions in meadows with high N input. Importantly, we found that the effects of N on interaction dynamics were particularly strong late in the season, suggesting heightened vulnerability of plant–pollinator interactions to N enrichment during this period. N-induced changes in plant–pollinator interaction dynamics further disrupted the structure of pollination networks in natural alpine meadows through reduced specialization and modularity, which suggests that pollinators interact with plants more opportunistically over time, resulting in more simplified and homogenized communities under high N input. By considering temporal dimension, our study demonstrates that anthropogenic N enrichment can interrupt seasonal connectivity and stability of plant–pollinator networks, providing novel insights into how and why anthropogenic environmental change affects multi-trophic interactions in vulnerable alpine ecosystems.

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摘要

因人类活动加剧，生态群落正受到快速而复杂的环境变化的胁迫，影响着生物间相互作用的稳定性以及生态系统功能。例如，植物–传粉者群落会因土地利用变化、物种入侵和气候变化而发生结构性转变。通过研究人为干扰导致的相互作用网络在时间尺度上的变化，我们能够更好地理解其潜在生态机制，并预测人类活动对群落的影响。在本研究中，我们利用一项长期氮(N)添加野外实验平台，探究氮富集对青藏高原高寒草甸季节动态的影响。考虑到高寒草甸短暂的花期和传粉者活动物候，我们尤其关注氮富集引起的开花植物群落变化如何在整个生长季中影响植物–传粉者相互作用的形成与解体过程，进而影响网络结构并决定群落的生态韧性。研究结果表明，氮添加导致花资源数量与多样性减少，进而导致植物-传粉者互作变得不稳定，加剧了传粉者物种在季节内的更替。这一变化进一步影响了时间上持续存在物种之间的自然相互作用重连过程，表明在高氮输入的草甸中，植物–传粉者相互作用的季节连通性显著降低。值得注意的是，氮对相互作用动态的影响在生长季后期尤为显著，说明在这一时期植物–传粉者相互作用对氮富集的更加敏感。氮富集引起的相互作用动态变化还通过降低网络的特化性和模块化程度，改变了自然高寒草甸中传粉网络的结构，表明在高氮输入条件下，传粉者随时间更倾向于以机会主义方式与植物互作，最终导致群落结构趋于简化和同质化。通过引入时间维度，本研究表明，氮富集能够破坏植物–传粉者网络的季节连通性与稳定性，为理解人为环境变化如何以及为何影响脆弱生态系统中的多营养级相互作用提供了新的见解。

Plant economics traits predict plant carbon allocation and responsiveness to arbuscular mycorrhizal fungi under varying precipitation

Hengjun Zhao, Huixuan Liao, Arjen Biere, Shaolin Peng — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Most terrestrial plant species form symbioses with arbuscular mycorrhizal fungi (AMF). However, the below-ground carbon (C) allocation of plants and the nutritional and growth benefits provided by AMF within this symbiosis vary greatly across species and environments. Currently, the extent to which this variation is governed by plant functional trait syndromes remains poorly understood. To address this, we conducted a ¹³C pulse labelling study with four grass species inoculated with three AMF species under four precipitation regimes to test whether plant below-ground C allocation and AMF-derived benefits can be explained by functional traits representing specific axes of the plant economics spectrum (PES). Our results demonstrate that the two main dimensions of the PES differentially predict the plant–AMF interaction. The first dimension (PC1), strongly aligning with a conservation-acquisition strategy, was a primary predictor of below-ground C allocation and its sensitivity to precipitation. The second dimension (PC2), defined by variation in specific root length (SRL) that strongly reflects a collaboration strategy, primarily governed nutrient-related mycorrhizal responses and their reactions to altered precipitation. Furthermore, path analyses revealed that these traits exert direct and AMF community-mediated indirect effects on the symbiosis. Synthesis. Our results highlight that species positions along plant economics strategy axes provide a predictive framework for plant C allocation and mycorrhizal responses. By demonstrating that trait–symbiosis coupling is modulated by precipitation, this study advances our ability to predict how plant–AMF interactions respond to environmental change.

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摘要

多数陆生植物均可与丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)形成共生关系。植物向地下分配的碳以及AMF介导的菌根响应在不同物种和环境背景下存在差异。然而，目前这种变异是否以及如何受植物功能性状调控仍缺乏研究。研究采用¹³C稳定性同位素标记，选取四种禾本科植物，设置四种降水与AMF混合菌剂接种与否处理，以探究植物经济谱(plant economics spectrum, PES)中的不同功能策略是否能够预测植物地下碳分配及菌根响应。结果表明，植物功能性状的两个主要维度对植物–AMF互作具有差异化调控作用:第一维(PC1)与“保守–获取”策略高度一致，是预测植物地下碳分配及其对降水敏感性的关键。第二维(PC2)以比根长(specific root length, SRL)的变化为主，反映植物“菌根协作”策略，是预测菌根响应及其对降水敏感性的主要指标。路径分析表明这些性状既可直接影响该共生关系，也可通过影响AMF群落组成产生间接作用。研究表明，物种在植物经济谱轴上的位置可为预测植物碳分配和菌根响应提供理论依据。通过揭示降水对功能性状–菌根共生耦合的调控作用，本研究为预测环境变化下的植物–AMF互作响应提供了新的理论框架。

Depth‐dependent mechanisms regulate accumulation of plant‐ and microbial‐derived residues under long‐term nitrogen addition in a semiarid grassland

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Plant- and microbial-derived residues constitute the primary sources of soil organic carbon (SOC) in grassland ecosystems. However, their differential responses to chronic nitrogen (N) enrichment and the depth-dependent mechanisms governing their accumulation remain poorly characterized, particularly for water-limited grassland systems. Based on a 13-year field experiment in a semiarid grassland, we quantified the effects of long-term N addition on the accumulation of plant- (lignin phenols) and microbial-derived (amino sugars) residues. We found that N addition significantly increased lignin phenol content and its contribution to SOC in the topsoil, whereas lignin phenols exhibited a hump-shaped response peaking under moderate N levels in the subsoil. Amino sugar concentrations and their relative contribution to SOC increased in both soil layers under N addition but declined at the highest N input. The dominant factors regulating residue accumulation varied with soil depth: in the topsoil, microbial K−/r-traits and community composition primarily explained lignin phenol and amino sugar dynamics, while in the subsoil, mineral-associated protection and microbial composition were the key drivers. These findings underscore the depth-dependent nature of SOC formation pathways and highlight the importance of incorporating both plant- and microbial-derived residues into Earth System Models to improve projections of carbon-climate feedback under changing nitrogen regimes.

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Spatiotemporal dynamics and machine learning‐based prediction of above‐ground biomass in the Indus Delta mangroves

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Mangrove forests are important blue carbon ecosystems, yet long-term above-ground biomass (AGB) dynamics in arid deltaic systems remain poorly understood. Here, we integrated field-derived AGB data with multisource remote sensing and machine learning models (random forest, gradient-boosted regression tree, support vector regression and classification and regression trees) to map historical patterns and predict future AGB dynamics in the Indus Delta mangroves for 2030, 2040 and 2050. AGB increased significantly over time, with mean values rising from 18.13 ± 9.1 Mg/ha in 2002 to 25.75 ± 8.32 Mg/ha in 2022, as indicated by Mann–Kendall trend analysis. Among models, GBRT performed best (R ² = 0.65, RMSE = 0.52) and projected continued increases in AGB to 30.31 ± 4.8 Mg/ha in 2030, 40.12 ± 6.4 Mg/ha in 2040 and 48.6 ± 7.9 Mg/ha in 2050. AGB was positively associated with vegetation indices and negatively related to land surface temperature and land-use change. Synthesis. Mangrove AGB in the Indus Delta is increasing and is projected to continue rising under current conditions, highlighting substantial carbon sequestration potential in arid coastal systems. The strong performance of machine learning models demonstrates their utility for large-scale biomass prediction, while the observed environmental controls emphasize the importance of sustaining freshwater input, sediment supply and restoration efforts for long-term ecosystem resilience and blue carbon management.

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خلاصہ

مینگرُوو کے جنگلات ساحلی علاقوں میں قدرتی طور پر کاربن محفوظ کرنے والے اہم ماحولیاتی نظام ہیں۔ یہ جنگلات موسمیاتی تبدیلی کے اثرات کو کم کرنے کے ساتھ ساتھ ساحلی علاقوں کو طوفانوں اور کٹاؤ سے بچانے میں بھی مدد دیتے ہیں۔ تاہم، خشک ڈیلٹائی علاقوں میں ان جنگلات کی اوپر زمینی حیاتیاتی کمیت میں طویل عرصے کے دوران ہونے والی تبدیلیوں پر اب تک کم توجہ دی گئی ہے۔ اسی پس منظر میں یہ مطالعہ انڈس ڈیلٹا کے مینگروو جنگلات میں بایوماس میں آنے والی تبدیلیوں کو سمجھنے کے لیے کیا گیا۔ اور مستقبل کے لیے بایوماس میں مزید اضافے کی پیش گوئی کی۔ اور اس تحقیق میں فیلڈ سے حاصل کردہ معلومات، سیٹلائٹ ڈیٹا، اور جدید مشین لرننگ طریقوں کو یکجا کیا گیا۔ نتائج سے معلوم ہوا کہ مان–کینڈل تجزیے کے مطابق 2002 سے 2022 کے دوران اوپر زمینی حیاتیاتی کمیت میں واضح اضافہ ہوا، جو 18.13 ± 9.1 میگا گرام فی ہیکٹر سے بڑھ کر 25.75 ± 8.32 میگا گرام فی ہیکٹر تک پہنچ گیا۔ مختلف مشین لرننگ ماڈلز میں گریڈینٹ بوسٹڈ ریگریشن ٹری نے سب سے بہتر نتائج دیے (R2 = 0.65، RMSE = 0.52) سکتا ہے۔ یہ تحقیق ساحلی کاربن منصوبہ بندی اور پائیدار ساحلی انتظام کے لیے ایک مفید اور قابلِ عمل بنیاد فراہم کرتی ہےاندازوں کے مطابق اوسط بایوماس 2030 میں 30.31 ± 4.8، 2040 میں 40.12 ± 6.4، اور 2050 میں 48.6 ± 7.9 میگا گرام فی ہیکٹر تک پہنچ سکتی ہے۔ مزید یہ کہ نباتاتی اشاریے بایوماس کے ساتھ مضبوط مثبت تعلق ظاہر کرتے ہیں، جبکہ زیادہ درجہ حرارت اور زمین کے استعمال میں تبدیلی بایوماس میں کمی سے جڑی ہوئی ہے۔ مجموعی طور پر یہ مطالعہ واضح کرتا ہے کہ اگر میٹھے پانی کی فراہمی، تلچھٹ کی ترسیل، اور مقامی سطح پر تحفظ کی کوششیں جاری رہیں تو انڈس ڈیلٹا کے مینگروو جنگلات میں بحالی کا عمل مزید مضبوط ہو

Juvenile predation overwhelms nutritional effects on female ungulate fat reserves in a high‐predation system

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Ungulate body fat reserves reflect the nutritional environment, often serving as a useful indicator of bottom-up resource availability. However, body fat reserves also integrate energetic costs associated with avoiding predation risk and reproductive effort, and it is unknown how bottom-up and top-down factors integrate to affect body fat reserves. We used generalized mixed-effects models to evaluate how bottom-up, top-down and intrinsic factors explained variation in winter ingesta-free body fat (IFBF) of female elk (Cervus canadensis) near Banff National Park, Alberta, Canada from 2015 to 2021. We found two top models were competitive, with calf survival during the first 3–4 months of life and female age included in both models. There was more support for bottom-up forage effects than indirect predation risk effects. Based on model predictions, females with a calf surviving through the previous summer had 3.6 percentage points (95% CI: 2.4%, 4.9%) lower IFBF the subsequent winter than females without a surviving calf. Because calf survival during the first 3–4 months of life is largely driven by predation in this system, we suggest top-down effects of predation through calf mortality influenced body fat around nine times more than bottom-up factors in our study. Under high predation, variation in body fat levels of female ungulates across a population may not reflect only bottom-up influences on body condition, but also differences in predation. Thus, both bottom-up and top-down factors must be considered when assessing the nutritional environment.

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The influence of a cluster‐rooted species on Bossiaea linophylla (Fabaceae) under extremely phosphorus‐impoverished conditions: Phosphorus competition and altered plant–microbe interactions

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Phosphorus (P) limitation may intensify plant competition. However, in severely P-impoverished soils of south-western Australia, cluster-rooted Banksia attenuata (Proteaceae) can facilitate P acquisition of neighbouring species by mobilising tightly bound P from soil particles. It remains unclear whether such facilitation also occurs in Bossiaea linophylla (Fabaceae), a native and symbiosis-dependent species that naturally coexists with B. attenuata, and whether these plant–plant interactions influence its association with arbuscular mycorrhizal (AM) fungi and N₂-fixing symbiotic bacteria. We conducted a multifactorial glasshouse experiment to characterise plant growth, root morphological traits and symbiotic associations with AM fungi and rhizobia at the sapling stage in B. linophylla grown either in monoculture or in mixed culture with B. attenuata in pasteurised soil or in pasteurised soil inoculated with soil from their natural habitat. The total biomass of B. linophylla saplings was significantly greater in monoculture than in mixed culture with B. attenuata, indicating interspecific competition. In monoculture, we observed greater total biomass of B. linophylla in inoculated soil than in pasteurised soil, suggesting that the native soil inoculum benefited plant growth. In the mixed culture, the competitor, B. attenuata, suppressed some beneficial microbial associations with B. linophylla, specifically, rhizobia, as reflected by markedly reduced root nodule numbers. Rather than facilitation, B. attenuata exerted competitive pressure on B. linophylla at the sapling stage, primarily through competition for P. Moreover, this competitive relationship influenced the interaction between B. linophylla and rhizobia. These findings highlight that plant–plant interactions can modulate plant-microbe relationships in extremely P-impoverished soils.

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Long‐term warming drives mineral‐associated organic carbon accumulation on the Tibetan Plateau

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Global warming affects both plant growth and soil microbial decomposition, creating uncertainty for the storage and persistence of soil organic carbon (SOC) stock. Limited decomposition rates often characterise cold alpine ecosystems. Yet, warming may increase their microbial activity, affecting SOC sequestration. Here, we present findings from a 14-year field warming study carried out in an alpine meadow on the Qinghai-Tibetan Plateau. Warming significantly increased mineral-associated organic carbon (MAOC) by 11% in topsoil and 6% in subsoil—primarily through an increase in iron/aluminium-bound organic carbon (Fe/Al-OC) in topsoil and calcium-bound organic carbon (Ca-OC) in subsoil. On the contrary, warming did not affect particulate organic carbon (POC). MAOC content was strongly positively correlated with soil fungal biomass and fungal necromass carbon, highlighting the role of fungal-derived carbon inputs. Our results reveal distinctly different responses of SOC pools to long-term warming and underscore the importance of organo-mineral interactions in shaping SOC dynamics in cold ecosystems under climate change.

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Forest type and leaf habit mediate thermal and drought tolerance across a tropical elevational gradient

Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Understanding how local climate patterns select for thermal and drought tolerance traits is needed to predict differential responses to climate change across complex ecosystems. Here, we used high-throughput methods to measure traits that confer heat and drought tolerance across a tropical climatic variability gradient and examined how forest type and leaf habit mediate these traits. We estimated thermotolerance thresholds (Tcrit, T50, T95), drought tolerance traits (water potential at turgor loss point [𝝭_TLP] and osmotic potential [𝞹_osm]), and morphological traits (wood density and leaf mass per area [LMA]) for 92 woody plant species across six sites along a tropical dry-to-wet gradient in Área de Conservación Guanacaste, Costa Rica. Among evergreen species, T95 weakly declined with elevation, LMA was positively associated with T50 and T95, and greater drought tolerance values were found at lower elevations and with greater wood density. Among deciduous species, no significant associations were found between tolerance traits and elevation or wood density, though LMA was positively associated with T50. T95 was higher on average among seasonal dry and ecotonal forest species compared with wet forest species. Additionally, evergreen species from dry and ecotonal forests exhibited greater drought tolerance than those from wet forests, whereas drought tolerance indices did not differ among deciduous species across forest types. These results point to multiple adaptive pathways for evergreen species and provide evidence that evergreen trees face greater drought-induced selection pressure. Surprisingly, thermal tolerance traits were largely decoupled with drought tolerance traits, suggesting that coordination among traits that confer tolerance to environmental stressors is not generalizable in tropical forests.

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RESUMEN

Comprender cómo los patrones climáticos locales seleccionan rasgos de tolerancia térmica y a la sequía es fundamental para predecir respuestas diferenciales al cambio climático en ecosistemas complejos. En este estudio, utilizamos metodologías rápidas de alto desempeño para medir rasgos que confieren tolerancia al calor y a la sequía a lo largo de un gradiente tropical de variabilidad climática, y examinamos cómo el tipo de bosque y el hábito foliar modulan estos rasgos. Estimamos umbrales de termotolerancia (Tcrit, T50, T95), rasgos de tolerancia a la sequía (potencial hídrico en el punto de pérdida de turgencia [𝝭_TLP], potencial osmótico [𝞹_osm]) y rasgos morfológicos (densidad de la madera y masa foliar por unidad de área [LMA]) para 92 especies de plantas leñosas a lo largo de seis sitios distribuidos en un gradiente tropical de seco a húmedo en el Área de Conservación Guanacaste, Costa Rica. En especies perennifolias, T95 disminuyó débilmente con la altitud, LMA se asoció positivamente con T50 y T95, y se observaron valores de mayor tolerancia a la sequía en altitudes más bajas y con mayor densidad de madera. En contraste, en especies caducifolias no se encontraron asociaciones significativas entre los rasgos de tolerancia y la altitud o la densidad de la madera, aunque LMA se asoció positivamente con T50. En promedio, T95 fue más alto en especies de bosques secos estacionales y del ecotono en comparación con especies de bosques húmedos. Además, las especies perennifolias de bosques secos y de ecotono mostraron mayor tolerancia a la sequía que aquellas de bosques húmedos, mientras que los índices de tolerancia a la sequía no variaron entre especies caducifolias según el tipo de bosque. Estos resultados apuntan a múltiples vías adaptativas para las especies perennifolias y aportan evidencia de que los árboles perennifolios enfrentan una mayor presión de selección inducida por la sequía. Contrario a lo esperado, los rasgos de tolerancia térmica estuvieron en gran medida desacoplados de los de tolerancia a la sequía, lo que sugiere que la coordinación entre rasgos que confieren tolerancia a factores de estrés ambiental no es generalizable en los bosques tropicales.

How vulnerable are amphibians to climate change? A mechanistic perspective

Eric A. Riddell, David R. Adams, Molly C. Womack — Tue, 02 Jun 2026 22:26:01 -0700

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Abstract

Amphibians are frequently identified as highly vulnerable to climate change, yet the mechanisms driving this sensitivity remain uncertain. Approaches that explicitly link physiological mechanisms to environmental variation provide powerful tools for forecasting climate vulnerability. However, their reliability depends on assumptions that accurately reflect the conditions amphibians experience in nature. Here, we evaluate the physiological mechanisms most often invoked to explain amphibian climate vulnerability, including overheating, desiccation, energetic constraints and seasonal dormancy and assess the ecological realism of current modelling frameworks. We show that broad-scale assessments often overlook widespread behavioural buffering, such as nocturnal activity, subterranean refuge use and close association with saturated microhabitats, which substantially reduce exposure to extreme temperatures and water loss. We also identify opportunities to improve mechanistic models by incorporating microclimatic heterogeneity, behavioural avoidance of stressful conditions and hydric landscape dynamics. Doing so will clarify when and where climate change poses a true physiological threat and provide greater insight into the processes shaping amphibian extinction risk. Grounding mechanistic forecasts in ecological reality is essential for avoiding mischaracterization of risk and for directing limited resources towards amphibian research, species and regions most in need.

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Resumen

Los anfibios son frecuentemente identificados como altamente vulnerables al cambio climático; sin embargo, los mecanismos que impulsan esta sensibilidad siguen siendo inciertos. Los enfoques que vinculan explícitamente los mecanismos fisiológicos con la variación ambiental proporcionan herramientas poderosas para predecir la vulnerabilidad climática. No obstante, su fiabilidad depende de supuestos que reflejen con precisión las condiciones que los anfibios experimentan en la naturaleza. Aquí evaluamos los mecanismos fisiológicos que con mayor frecuencia se invocan para explicar la vulnerabilidad climática de los anfibios, incluidos el sobrecalentamiento, la desecación, las limitaciones energéticas y la dormancia estacional, y analizamos el realismo ecológico de los marcos de modelización actuales. Mostramos que las evaluaciones a gran escala a menudo pasan por alto la amplia amortiguación conductual, como la actividad nocturna, el uso de refugios subterráneos y la estrecha asociación con microhábitats saturados, que reducen sustancialmente la exposición a temperaturas extremas y a la pérdida de agua. También identificamos oportunidades para mejorar los modelos mecanicistas incorporando la heterogeneidad microclimática, la evitación conductual de condiciones estresantes y la dinámica hídrica del paisaje. Hacerlo permitirá aclarar cuándo y dónde el cambio climático representa una amenaza fisiológica real y proporcionará una mayor comprensión de los procesos que determinan el riesgo de extinción de los anfibios. Fundamentar las predicciones mecanicistas en la realidad ecológica es esencial para evitar la caracterización errónea del riesgo y para dirigir los recursos limitados hacia la investigación, las especies y las regiones de anfibios que más lo necesitan.

Linking rhizosphere bacterial succession to metabolite dynamics unravels the underlying survival strategies of desert ephemeral plants

Yang Yang, Weiguo Liu, Xi‐En Long, Yangyang Jia, Xiaodong Yang — Tue, 02 Jun 2026 03:09:42 -0700

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Abstract

Desert ephemerals complete rapid life cycles to survive aridity, yet the ontogenetic coordination of below-ground rhizosphere interactions with above-ground resource allocation remains unclear. This study examined six dominant ephemeral species (Eremurus inderiensis, Eremopyrum orientale, Erodium oxyrrhynchum, Allium mongolicum, Alyssum linifolium and Nepeta micrantha) in the Gurbantünggüt Desert across seedling and flowering stages, integrating plant biomass, rhizosphere metabolites and bacterial communities. This study detected consistent ontogenetic shifts at the overall level: a 44.4% decrease in root: shoot ratio shifting biomass from below-ground to above-ground with interspecific variations. Concurrently, rhizosphere metabolic space contracted by 86.4%, with species-specific metabolic plasticity strongly correlated with biomass reallocation magnitude. Bacterial communities exhibited reduced α-diversity, simplified co-occurrence networks and a predicted functional transition from carbon to nitrogen metabolism. Keystone microbe–metabolite associations shifted from carbon-based linkages at the seedling stage to nitrogen-centric correlations at flowering, accompanied by stage-specific turnover of keystone taxa and reconfiguration of microbe–metabolite networks. At the species level, however, the key taxa, metabolites and network dynamics underlying these shifts were highly specific, with divergent niche-width dynamics and stage-specific interactions corresponding to host metabolic plasticity. Path modelling revealed a universal, stage-dependent reversal in biomass drivers: below-ground biomass was initially supported by broad bacterial niche width, whereas flowering-stage above-ground biomass was directly driven by rhizosphere metabolites. These findings demonstrate that host developmental stage orchestrates a phased rhizosphere strategy in desert ephemerals. This strategy synchronizes keystone taxa succession and microbe–metabolite network reconfiguration with plant ontogenetic goals, enabling a conserved shift from microbial-assisted establishment to metabolite-driven reproduction despite species-specific pathways. This study provides novel insights for plant–microbe co-adaptation in resource-limited desert ecosystems.

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Soil drying induces widespread productivity loss but unequal climate vulnerability among ecotypes of a foundational Arctic sedge

Jonathan Gewirtzman, Ned Fetcher — Mon, 01 Jun 2026 23:46:59 -0700

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Abstract

As temperatures increase in the Arctic, hydrological change may lead to local soil drying through altered snowpack, evapotranspiration and drainage due to permafrost thaw. These changes threaten to alter soil moisture regimes that control plant productivity and ecosystem carbon cycling. Eriophorum vaginatum, a foundational sedge that accounts for up to 30% of carbon uptake in moist tundra ecosystems, exhibits substantial local adaptation across its range, yet its capacity to maintain productivity under changing soil moisture conditions remains unknown. We conducted a common garden experiment using tussocks from three populations along a latitudinal gradient in northern Alaska, subjecting them to two treatments simulating surface soil drying and deeper drainage from permafrost thaw. Through measurements of plant water status, photosynthetic capacity and seasonal growth patterns, we found that soil drying substantially reduced productivity across all populations through both decreased photosynthesis and reduced leaf area, with the deeper drainage treatment having a greater effect. Plants responded to moisture stress primarily by reducing canopy size rather than through leaf-level drought acclimation, with southern populations showing greater vulnerability to drought stress. Our findings highlight regional differences in drought susceptibility and suggest that shifts in soil moisture could influence Arctic plant productivity and carbon cycling under future climate.

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Land use overrides climatic controls on soil organic nitrogen transformations: Contrasting responsiveness between forest and cropland ecosystems

Mon, 01 Jun 2026 23:45:29 -0700

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Abstract

Soil organic nitrogen (SON) transformation is critical for global nutrient cycling and ecosystem productivity, yet how its responsiveness to climate change differs across diverse land use types remains poorly resolved. We measured gross protein depolymerization (GPD), microbial N growth, gross N mineralization (GNM) and microbial N use efficiency (NUE) in paired forest and cropland soils along a broad climatic gradient in subtropical China to quantify differential climate associations and identify governing biogeochemical controls. Forest soils exhibited substantially higher GPD (82%), microbial growth (132%) and NUE (26%) compared to adjacent croplands, while GNM rates were similar between land uses. Across the observed spatial climate gradient, SON transformations in forests showed strong positive co-variation with climate: GPD, N_growth and GNM increased with mean annual temperature (MAT) and mean annual precipitation (MAP) (slopes for MAT = 0.59, 0.84, 0.49; for MAP = 0.55, 0.62, 0.23), whereas NUE declined with both MAT and MAP (slopes = −0.68 and −0.63, respectively). In contrast, cropland SON processes were largely insensitive to MAT and MAP except that N_growth and NUE increased modestly with MAT. Mechanistic analyses indicated contrasting regulatory pathways: in forests, climatic effects were transmitted mainly through mineral–enzyme interactions (e.g. iron/aluminium oxides modulating protease activity) and resource stoichiometry (e.g. dissolved organic carbon:available phosphorus ratio), with GPD tightly coupled to N_growth and GNM and acting as a rate-limiting step. In croplands, temperature effects were largely indirect, operating through base cation to iron/aluminium-oxide ratios, resource availability (free amino acids, carbon:N ratio), and microbial functional gene abundances, yielding a decoupling of depolymerization from downstream processes. These results show that land use strongly modulates the climate-associated responsiveness of SON transformations: forest soils are more vulnerable to climate-driven changes in N cycling than intensively managed croplands. Our findings have implications for land-use-specific management and for improving predictions of N dynamics under global change.

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土壤有机氮(SON)转化是驱动氮循环与维持生态系统生产力的核心环节。然而，在不同土地利用类型下，SON转化对气候变化的响应差异及其内在机制，至今仍缺乏系统且深入的认识。依托中国亚热带大尺度的空间气候梯度，本研究对配对的森林与农田土壤进行了系统比较研究，测定了蛋白质初级解聚(GPD)、微生物氮同化生长(N_growth)、初级氮矿化(GNM)以及微生物氮利用效率(NUE)等关键生态指标，旨在量化气候因素对上述过程的差异化影响，并揭示其内在的生物地球化学主控机制。结果表明显示，与相邻农田相比，森林土壤表现出显著更高的GPD (+82%)、N_growth (+132%)和NUE (+26%)，而两者的初级氮矿化(GNM)速率则无显著差异。沿空间气候梯度，森林土壤的SON转化与气候因子呈现强烈的协同响应:GPD、N_growth及GNM均随年均温(MAT)和年降水量(MAP)的升高而显著增加(MAT效应斜率依次为0.59、0.84、0.49；MAP效应斜率依次为0.55、0.62、0.23)，而NUE则随之显著下降(斜率分别为 -0.68 和 -0.63)。相反，农田土壤的SON转化过程对水热条件变化普遍缺乏敏感性，仅N_growth与NUE随温度升高呈微弱增加趋势。机制分析进一步揭示了两类生态系统截然不同的调控路径:在森林中，气候效应主要由矿物-酶交互作用(如铁铝氧化物对蛋白酶活性的调节)及资源化学计量特征(如可溶性有机碳与有效磷比值)介导；在此过程中，GPD作为关键的限速步骤，与下游的N_growth及GNM紧密耦合。而在农田中，温度效应多表现为间接控制，主要受控于盐基离子/铁铝氧化物比值、底物有效性(如游离氨基酸、碳氮比)以及微生物功能基因丰度，这种调控模式最终导致上游蛋白质解聚与下游转化过程发生解耦。本研究表明，土地利用方式深刻调控了土壤有机氮转化对气候变化的响应模式:相较于集约管理的农田，森林土壤的氮循环对气候驱动的环境扰动更为敏感与脆弱。该研究结果不仅为制定基于土地利用类型的差异化生态管理策略提供了重要依据，也为优化全球变化背景下的地球系统模型、提高氮动态预测的准确性提供了关键支撑。

Plant functional groups and root traits are linked to exudation rates of mature temperate trees

Fri, 29 May 2026 05:32:23 -0700

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Abstract

Root exudation affects soil biogeochemistry profoundly, yet it is rarely quantified in mature, field-grown trees and its controls are poorly understood. We measured rates of carbon (C) exudation in 11 tree species that exhibit divergent root traits, including gymnosperms and angiosperms that associate with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EcM) fungi. Our goal was to explore how tree species, plant functional groups and root traits collectively influence exudation patterns. Species-level differences were modest owing to substantial intraspecific variability (among individuals of the same species). However, three of the four highest exuding species were EcM gymnosperms, which exuded ca. two times more C than the other functional groups. Principle component analysis revealed that relationships between root trait organization and exudation were pronounced in EcM-associated trees but weak or absent in AM-associated trees. In EcM trees, exudation rates were negatively correlated with root tissue density (RTD) and positively correlated with specific root area (SRA) and root diameter, driven largely by gymnosperms. In contrast, exudation in AM trees showed only a weak association with specific root length. Consistent with these findings, mixed-effect models also showed that exudation rates were best explained by a combination of tree-mycorrhizal type, phylogenetic group and SRA, though a large portion of unexplained variation suggests an important role for contemporary environmental and local edaphic conditions. Collectively, our results demonstrate that root exudation is a complex physiological process shaped by interactions among mycorrhizal associations, evolutionary history and root traits, rather than by functional groups or root traits alone. These findings highlight the urgent need for more integrative frameworks and new experimental approaches to incorporate exudation dynamics into plant strategy theory and large-scale ecosystem models.

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Developmental plasticity drives converge nt shifts in phosphorus acquisition strategies towards root phosphatase activity in Moso bamboo under nitrogen addition

Fri, 29 May 2026 05:27:55 -0700

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Abstract

Anthropogenic nitrogen (N) deposition is a major driver of global change. However, its effects on the developmental plasticity of plant nutrient strategies remain poorly understood. This is particularly critical in phosphorus (P)-limited subtropical forests, where N-induced shifts in biogeochemical cycles may intensify P constraints. Using Moso bamboo (Phyllostachys edulis) as a model system, we investigated the response of root P acquisition strategies and leaf P fractions to different N addition (0, 30 and 60 kg N ha⁻¹ year⁻¹) at different developmental stages (young vs. mature). We identified a convergent shift in P acquisition pathways in response to N addition. Young bamboos transitioned from morphological strategies (specific root length and area) to exudation-based strategies, whereas mature bamboos shifted from carboxylate-dominated to phosphatase-enhanced pathways. Ultimately, both stages converged on root phosphatase-mediated organic P mobilization. This strategic unification was also observed in the leaves. N addition significantly reduced leaf inorganic P pools without altering lipid-P, residual-P and nucleic-P, indicating a prioritization of P for growth under intensified limitation. Key drivers, including soil acidification, depletion of available P, accumulation of microbial biomass P, and increased root phosphatase activity, collectively influenced this root–leaf recalibration. Furthermore, responses in root P acquisition strategies and leaf P fractions saturated at the low N addition level, indicating a non-linear threshold effect rather than a proportional dose–response. By integrating specific root pathways and internal P fraction dynamics, our study advances the conventional ‘Get–Save–Return’ framework and underscores developmental plasticity as a central mechanism in clonal plant responses to N deposition. These findings provide a new mechanistic insight into nutrient cycling in subtropical forests under global climate change.

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摘要

氮沉降是全球变化的重要驱动因子，但其对植物养分策略发育可塑性的影响仍不清楚。在受磷限制的亚热带森林中，这一问题尤为关键，因为氮沉降驱动的生物地球化学循环变化可能进一步加剧磷限制。本研究以毛竹(Phyllostachys edulis)为对象，探究了不同发育阶段(幼竹和成竹)的根系磷获取策略与叶片磷组分对不同梯度氮添加(0、30、60 kg N ha^-1 year^-1)的响应。研究发现，氮添加下磷获取策略发生趋同转变:幼竹从形态途径(如比根长和比表面积)转向依赖根系分泌物，成竹则从以羧酸盐为主的途径转向增强磷酸酶途径，二者最终均趋同于磷酸酶介导的有机磷活化途径。叶片层面也呈现统一性，氮添加显著降低叶片无机磷含量，但未改变脂质磷、残余磷和核酸磷含量，表明在加剧的磷限制下植物优先将有限磷分配给生长。土壤pH、有效磷、微生物生物量磷和根系磷酸酶活性是关键驱动因素，共同促成了根-叶性状的协同重塑。此外，根系磷获取策略和叶片磷组分对低水平氮添加表现出饱和响应，这揭示了一种非线性阈值效应，而非简单的等比例剂量-响应关系。通过整合特定根系途径与叶片磷组分动态，本研究拓展了“获取-保存-归还”理论框架，并突出了发育可塑性作为克隆植物响应氮沉降的核心机制，为理解全球变化背景下亚热带森林养分循环提供了新的机制性见解。

Leaf C:P ratio as a universal indicator of photosynthesis in subtropical woody species: Stoichiometric thresholds and metabolic trade‐offs

Thu, 28 May 2026 00:36:38 -0700

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Abstract

The stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) serve as important indicators for assessing nutrient balance in forest ecosystems, but their relationships with photosynthetic dynamics require deeper characterization. This study systematically examined the associations between leaf C-N-P stoichiometry and photosynthetic traits across 92 dominant woody species in subtropical regions. We found that the C:P ratio exhibited the greatest variation across species compared to other stoichiometric ratios, indicating that it responds sensitively to environmental conditions. Among all stoichiometric parameters, leaf C:P displayed the strongest correlation with maximum net photosynthetic rate (A _max), closely linked with its coordinated variations in stomatal conductance, chlorophyll content and specific leaf area. In-depth metabolic analysis of 31 representative species revealed that leaf C:P ratio effectively captured two critical processes: (1) the accumulation patterns of photosynthetic products and (2) the metabolic P allocation regulated by acid phosphatase activity. This dual sensitivity enabled C:P to serve as a synthetic indicator reflecting both carbon assimilation efficiency and phosphorus metabolic status. In contrast, N:P ratio showed limited predictive value for A _max due to its inability to integrate the co-variation of photosynthetic product dynamics and nutrient regulation. Our findings establish leaf C:P ratio as a robust bioindicator for evaluating photosynthetic performance in subtropical forests. This metric not only enhances our capacity to monitor carbon sink potential but also provides critical insights for optimizing phosphorus management strategies in artificial afforestation programs.

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摘要碳(C)、氮(N)、磷(P)的化学计量比是评估森林生态系统养分平衡的重要指标，但其与光合作用的关系仍缺乏深入探究。. 本研究系统考察了亚热带地区92种优势木本植物叶片C-N-P化学计量特征与光合性状的关联。结果表明，与其他化学计量比相比，C:P比在物种间变异幅度最大，表明其对环境条件变化响应敏感。在所有计量参数中，叶片C:P比与最大净光合速率(A _max)相关性最强，且与气孔导度、叶绿素含量和比叶面积的协同变化密切相关。. 我们对31个代表性物种的代谢机制深入分析显示，叶片C:P比能有效捕捉两个关键过程:(1)光合产物的积累模式；(2)受酸性磷酸酶活性调控的磷代谢分配。这种双重敏感性使C:P比成为综合反映碳同化效率和磷代谢状态的指标。相比之下，N:P比由于无法整合光合产物动态与养分调控的变化规律，对A _max的预测价值有限。. 本研究确立叶片C:P比可作为评估亚热带森林光合性能的可靠生物指标。该指标不仅能提升我们对碳汇潜力的监测能力，还能为人工造林项目中磷素管理策略提供重要依据。

Correction to ‘Evolutionary constraints in host shifts: Limited adaptation of Plutella xylostella to cardenolide‐defended Erysimum cheiranthoides’

Tue, 26 May 2026 22:35:59 -0700

Functional Ecology, EarlyView.

Root and leaf litter diversity below‐ground shape soil carbon stabilization and priming through altered decomposition dynamics

Raoul Huys, Vincent Poirier, Grégoire T. Freschet — Thu, 21 May 2026 10:50:24 -0700

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Abstract

Root and leaf turnover is a major contributor to soil organic carbon (SOC) dynamics and storage. However, while roots of multiple species occur in soils, and leaves are often incorporated to soil by bioturbation processes, it remains unknown how litter mixing in soils influences litter decomposition processes. Particularly, it is unknown how the soil may interact with (e.g. buffer or amplify) the expected redistribution of litter compounds between mixed litters (e.g. nitrogen [N] and tannins), with consequences for litter decomposition and the resulting carbon (C) fluxes controlling the SOC balance. To address this issue, we studied the (almost complete) decomposition of ¹³C labelled single leaf and root litters and 15 realistic litter mixtures incorporated into soil in the laboratory. We studied litter mass loss and litter N concentration as litters decomposed, tracked litter ¹³C into the mineral-associated organic matter (MAOM) and particulate organic matter (POM) fractions of the SOC, and quantified litter influence on native SOC mineralization (i.e. priming). We expected nutrient (in particular N) transfer between litters with dissimilar initial nutrient content to (1) stimulate C loss in mixed litters, although this effect would be potentially hampered by litter tannins, to (2) enhance SOC formation, and (3) limit SOC mineralization. As hypothesized, litter diversity increased litter decomposition rates, yet not due to N transfer and immobilization in decomposing litters. Also unexpectedly, litter tannins dissimilarity enhanced decomposition rates. Plant litter diversity enhanced soil MAOM-C formation, but had a negligible impact on overall SOC stocks. This occurred because SOC formation and priming mixture effects in the MAOM fraction were counterbalanced by those in the POM fraction. In mixed litters, the dissimilarity in litter manganese (Mn) was responsible for non-additive MAOM-C gains and POM-C losses, suggesting Mn transfer between litters that foster lignin degradation and incorporation into soil MAOM. Litter dissimilarity in Mn also reduced MAOM-C and increased POM-C priming. Overall, we demonstrate that diversity effects, potentially implying nutrient transfer between litters, can occur below-ground among root litters, as well as biologically incorporated leaf litters. It further shows that different nutrients are implicated in diversity effects controlling litter decomposition rate and soil C storage.

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All roads lead to infection: A mechanistic model to assess transmission routes of brucellosis in a wild ungulate population

Thu, 21 May 2026 10:47:57 -0700

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Abstract

Wildlife and domestic populations frequently share diseases with a potential for cross-species transmission, posing significant threats to animal and human health, economy and biodiversity conservation. While quantifying disease transmission in natural populations is critical to understand the dynamics of infectious diseases, transmission processes remain difficult to assess as they are difficult to observe directly. Brucellosis, caused by Brucella melitensis and Brucella abortus, is one of the most important worldwide zoonotic diseases and affects both domestic and wild ruminants. Here, we investigated the transmission of B. melitensis in an Alpine ibex (Capra ibex) population, the first known wild-living reservoir for this pathogen. We aimed to quantify disease transmission within the population by disentangling the contributions of four alternative transmission routes: abortion products, infectious parturition products, venereal transmission and vertical transmission. We modelled host-disease dynamics developing a spatially explicit, sex- and age-structured individual-based model that reproduces host demography and pathogen transmission by contacts among susceptible and infectious individuals. By fitting our model on 13 years of host-population and disease monitoring, we estimated the relative importance of the four transmission routes. We quantified the proportion of transmissions attributed to each route and estimated the effective reproduction number (R _eff), distinguishing age- and sex-specific contribution. We identified abortion products as the primary driver of Brucella transmission, accounting for 57%–85% of all transmissions. All other routes were of secondary importance, although the contribution of venereal transmission remained uncertain (from 4% to 25%). Females played a central role in disease maintenance, with an effective reproduction number well above one (2.1), while males' contribution was quantitatively negligible with a value below one (0.4). Our results provide key insights to implement targeted management operations. Since most transmissions occur through abortion products, targeting recently infected females could reduce the effective reproduction number below one, promoting pathogen extinction. Furthermore, because abortions are expected to peak in late spring, control measures aiming to limit transmission from ibex to other species, including livestock, should be prioritized during this high-risk period.

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Afforestation mitigates soil nitrogen limitation by enhancing mineralization and lowering denitrification in central China

Thu, 21 May 2026 10:46:05 -0700

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Abstract

Afforestation has profoundly altered soil nitrogen (N) transformation, particularly the key processes governing soil organic N and inorganic N dynamics which determine soil N availability. However, the divergences in soil N transformation and the main influencing factors following different afforestation types have not been systematically clarified. Here, we examined soil net N mineralization rate (NMR), net nitrification rate (NNR) and potential denitrification rate (PDR) at 144 paired sampling sites by comparing different afforestation types (initial land use types and tree species) in central China. Afforestation significantly enhanced soil NMR, but lowered NNR and PDR, respectively, compared to non-afforested lands. Soil NMR and PDR responses to afforestation from cropland were more sensitive than those from shrubland. Notably, broadleaf afforestation (i.e. Quercus variabilis) had a stronger effect on altering NMR compared to coniferous afforestation (i.e. Platycladus orientalis) from cropland. These variations in soil NMR and NNR responses were primarily attributed to soil properties (e.g. soil organic nitrogen [SON], soil organic carbon [SOC], C: N ratio) across both non-afforested and afforested lands, whereas the main influencing factor for PDR shifted from microbial traits in non-afforested lands to soil properties in afforested lands. Although higher SON contents promoted soil NMR in afforested lands, significantly higher microbial biomass N in the afforested lands compared to non-afforested lands suggested intensified microbial inorganic N assimilation, which consequently constrained NNR and PDR relative to non-afforested lands, further avoiding N loss and N limitation. Our findings emphasized that afforestation types divergently influenced soil net N transformation rates with overall impacts on alleviating possible soil N constraints, thereby providing a theoretical basis for the regulation of soil N cycling under future afforestation and forest management.

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Endogenous colony dormancy shapes seasonal cold tolerance in temperate ants

Quentin Willot, Vladimir Kostal, Martin Moos, Johannes Overgaard — Thu, 21 May 2026 10:44:45 -0700

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Abstract

As eusocial superorganisms, cold-adapted ants must survive multiple consecutive winters and are shaped by selective pressures acting at both individual and colony-level. Following winter reactivation, colonies enter a fixed developmental phase whose duration is regulated by ‘Kipyatkov's sand-glass device’, an endogenous timer that enforces the onset of a new dormancy period after a set interval even under permissive light and temperature conditions. However, how this obligate colony-level programming interacts with worker physiological responses to produce cold-tolerant phenotypes capable of withstanding seasonality remains unknown. Here, we leveraged obligate colony-level seasonal programming in five temperate ant species to disentangle the relative contributions of endogenous colony dormancy and exogenous thermal exposure (acclimation) on worker metabolic rates, metabolomic profiles and cold tolerance. We show that across the tested species, the onset of colony dormancy alone is sufficient to modulate both the critical thermal minimum (CT_min) and the temperature causing 50% mortality during acute cold exposure (LTe₅₀) and further interacts with acclimation to shape worker cold tolerance. Cold acclimation triggered the accumulation of metabolites (e.g. trehalose, glycerophosphoethanolamine) potentially involved in osmotic balance and membrane reorganization in individuals. Our results highlight that programmed, obligate colony dormancy in temperate ants can drive cold hardening in workers independently of environmental exposure. This suggests that cold tolerance in temperate social insects can emerge from the interplay between colonial seasonal programming and individual responses to environmental cues, reflecting their unique evolutionary history and social organization.

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Resolving the paradox of local warning signal diversity: A framework for hypothesis testing

Chi‐Yun Kuo, Shu‐Ping Tseng — Thu, 21 May 2026 09:39:17 -0700

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Abstract

Defended prey often evolve conspicuous colorations that advertise their unprofitability to predators. These visual advertisements act as honest warning signals that predators can use to avoid these prey through associative learning. Müller's pioneering idea aptly explains the often-observed signal convergence among unprofitable prey (i.e., Müllerian mimicry) as the result of positive frequency-dependent selection. We therefore expect aposematic prey, at least those targeted by the same predators, to be homogeneous in signal appearance at local scales. Yet, it is common to observe diverse warning signals coexisting within communities. The simultaneous occurrence of warning signal convergence and diversity at local scales represents a stark contrast with theoretical expectations and has long stood as a paradox. Despite much interest in this phenomenon, there has not been an article that summarizes possible resolutions of the paradox and, more importantly, offers an empirical framework for hypothesis testing. We aim to fill these knowledge gaps by summarizing possible resolutions to this paradox, including (1) relaxed predation, (2) microhabitat segregation, (3) source–sink dynamics, (4) retentive predators, (5) immigration boost, (6) immigration rescue and (7) imminent signal extinction. We also propose a hierarchical hypothesis-testing framework leveraging data from population surveys, genetic analyses and field learning experiments to elucidate the plausibility and contribution of these mechanisms. Our proposed framework would help resolve this long-standing paradox in natural communities. By applying this framework to communities harbouring diverse warning signals and differing in their ecological environments, we can test hypotheses regarding how local warning signal diversity is being maintained at larger scales, and how ecology might have shaped the nature of resolutions.

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Root economic space is associated with rhizosphere microbial divergence via root metabolite‐mediated pathways in degraded grasslands

Wed, 20 May 2026 23:13:41 -0700

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Abstract

Grasslands worldwide are experiencing severe degradation due to overgrazing, climate change and anthropogenic disturbances, resulting in substantial declines in biodiversity and ecosystem functioning. Although degradation is known to alter soil properties and disrupt plant–microbe interactions, it remains poorly understood how the root economic space (RES) and its associated rhizosphere metabolites drive the divergent responses of bacterial and fungal community in degraded grasslands. Elucidating these mechanisms is essential for developing effective microbiome-based restoration strategies. We employed a multi-omics approach, integrating 16S rRNA and ITS amplicon sequencing with metabolomic profiling, to investigate the rhizosphere microbiomes and metabolites of four plant species across three sites in the Inner Mongolian steppe. We measured root functional traits related to the root collaboration gradient (specific root length and root diameter) and the root conservation gradient (root tissue density and root nitrogen content), along with key soil properties, to disentangle their roles in shaping microbial community structure and diversity. Bacterial communities were significantly structured by host species identity. The root collaboration gradient was directly or indirectly associated with bacterial diversity via metabolite-mediated pathways, with rhizosphere exudate composition accounting for over 85% of the variation, highlighting plants' capacity to sustain tight associations with bacterial communities under degradation stress. In contrast, fungal communities were largely unresponsive to rhizosphere metabolites and instead structured by degradation-altered soil properties (e.g. pH, nitrogen), which explained 79.72% of the variance, with the root conservation gradient contributing an additional 20.14%. Network analyses further revealed more cohesive bacterial co-occurrence patterns, while fungal networks exhibited higher modularity and greater sensitivity to environmental conditions under degradation. These findings demonstrate a robust link between root economic space and rhizosphere microbiome structure. Our study provides an integrative framework that connects plant functional traits and root metabolites to microbial communities in degraded grasslands and highlights the prospect for using targeted plant–metabolite–microbe interactions to enhance restoration outcomes by selecting species that promote beneficial microbial communities.

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摘要

全球草地因过度放牧、气候变化和人为干扰而出现严重退化，导致生物多样性和生态系统功能显著下降。尽管已知退化会改变土壤性质并破坏植物-微生物互作，但在退化草地中，根系经济空间及其相关的根际代谢物如何驱动细菌和真菌群落的差异化响应，仍鲜有研究。阐明这些机制对于制定基于微生物组的有效恢复策略至关重要。我们采用多组学的方法，整合16S rRNA和ITS扩增子测序与代谢组学，研究了内蒙古草原三个样点四种植物的根际微生物组及代谢物。同时测量了与根系协作梯度(比根长和根直径)和根系保守梯度(根组织密度和根氮含量)相关的根系功能性状，以及关键的土壤理化性质，以解析它们在塑造微生物群落结构和多样性中的作用。细菌群落主要受宿主植物身份的显著影响。根系协作梯度通过代谢物介导的途径直接或间接地与细菌多样性相关，其中根际分泌物组成解释了超过85%的变异，突显了植物在退化胁迫下通过根际分泌物维持与细菌群落紧密关联的能力。相比之下，真菌群落对根际代谢物基本不响应，而主要受退化改变的土壤性质(如pH、氮含量)所调控，这些性质解释了79.72%的变异，根系保守梯度额外贡献了20.14%。网络分析进一步揭示，退化条件下细菌的共现模式更具内聚性，而真菌网络则表现出更高的模块化程度和对环境条件的更高敏感性。这些发现证明了根系经济空间与根际微生物组结构之间的强关联。我们的研究提供了一个整合框架，将退化草地中的植物功能性状和根系代谢物与微生物群落联系起来，并提出了通过选择能够促进有益微生物群落的植物物种，利用靶向的植物-代谢物-微生物互作来提升草地恢复效果的前景。

Cumulative heatwave stress disrupts thermal homeostasis and plumage structure in a Mediterranean passerine

Sat, 16 May 2026 00:00:00 -0700

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Abstract

Heatwaves are becoming increasingly frequent across the Mediterranean and pose critical challenges for small passerines, yet the physiological and morphological limits to their resilience remain poorly understood. We exposed Great tits (Parus major) to four consecutive simulated heatwaves and quantified thermoregulatory responses, oxidative stress and feather development under controlled conditions. Heat-exposed birds maintained persistently elevated body temperatures (+0.2°C) while exhibiting a lower probability and reduced within-hour expression of hyperthermia events relative to controls. Circadian modulation of body temperature and heterothermy was context dependent across successive heatwaves, indicating altered precision of thermal regulation rather than a uniform loss of rhythmicity. These thermophysiological adjustments were accompanied by sustained oxidative damage and reduced antioxidant capacity, whereas body mass and feather corticosterone levels remained unchanged. Feathers grown under heat stress exhibited reduced barb and barbule density and brighter, more UV and red-shifted coloration, consistent with altered feather microstructure and potential changes in insulative and signalling properties. Our results demonstrate that recurrent sublethal heat exposure rapidly engages thermoregulatory and morphological plasticity but entails measurable physiological costs. The limited buffering capacity of phenotypic flexibility highlights the need to identify trait-specific thresholds and potential carry over effects when forecasting avian resilience to climate change.

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Resumen

Las olas de calor son cada vez más frecuentes en la región mediterránea y suponen un desafío crítico para los paseriformes pequeños; sin embargo, su resiliencia frente a estos eventos mediada por ajustes en sus rasgos fisiológicos y morfológicos sigue estando poco estudiada. Individuos de carbonero común (Parus major) fueron sometidos a cuatro olas de calor simuladas consecutivas y se cuantificaron, en condiciones controladas, la respuesta termorreguladora, el estrés oxidativo y el desarrollo del plumaje. Las aves expuestas al calor mantuvieron temperaturas corporales persistentemente más elevadas (+0.2°C) y presentaron una menor probabilidad e intensidad de episodios de hipertermia en comparación con los individuos control. Además, la modulación circadiana de la temperatura corporal y de la heterotermia varió de forma diferencial entre olas de calor sucesivas, lo que sugiere una alteración en la precisión de la regulación térmica más que una pérdida uniforme de la ritmicidad. Estos ajustes fisiológicos estuvieron asociados a un daño oxidativo sostenido y una reducción de la capacidad antioxidante, mientras que la masa corporal y los niveles de corticosterona en plumas permanecieron inalterados. Las plumas que crecieron bajo estrés térmico presentaron una menor densidad de barbas y bárbulas, así como una coloración más brillante, con mayor reflectancia en el ultravioleta y desplazada hacia longitudes de onda más rojas, en consonancia con cambios en la microestructura del plumaje y que podría afectar sus propiedades aislantes y de señalización. Nuestros resultados demuestran que la exposición repetida a niveles subletales de estrés por calor activa rápidamente la plasticidad termorreguladora y morfológica, aunque conlleva costes fisiológicos medibles. La limitada capacidad amortiguadora de la flexibilidad fenotípica pone de manifiesto la necesidad de identificar umbrales específicos de cada rasgo y posibles efectos de arrastre para poder predecir la resiliencia de las aves frente al cambio climático.

High nitrogen loading impacts the temperature‐size rule and heat tolerance in a nettle‐feeding butterfly

Fri, 15 May 2026 02:43:16 -0700

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Abstract

Host-plant quality and ambient temperature are key environmental drivers of herbivorous insect performance, affecting growth, development, and survival. While temperature accelerates physiological processes in ectothermic insects, nutrient limitation in host plants can constrain insect herbivore fitness. Yet, few studies have examined how these two factors interact to shape insect herbivore performance. We experimentally quantified the combined effects of host-plant stoichiometry and rearing temperature on the larval growth rate, development time, and adult heat tolerance of the Map butterfly (Araschnia levana L. 1758). Caterpillars were reared on stinging nettle (Urtica dioica L.) cultivated under three nutrient addition regimes differing in N:P ratios—to alter the nutrient stoichiometry of their host plants—and under two diurnally fluctuating temperature regimes simulating ambient (day–night: 21°C/12°C) and elevated (day–night: 24°C/16°C) conditions. Both temperature and host plant stoichiometry affected butterfly performance. Warming and a balanced stoichiometry enhanced growth and development; under these favourable conditions, caterpillars exhibited rapid growth, faster development, higher survival, and increased adult heat tolerance. A trade-off between size and age at maturity—individuals either matured rapidly at smaller sizes or more slowly at larger sizes—was observed only under conditions that were favourable for growth, suggesting that developmental time was the main limiting factor under these conditions for the final butterfly body size. Our results thus demonstrate that host plant nutrient imbalances can mediate how insect herbivores prioritize between size and age at maturity under warming conditions, influencing thermal tolerance too. This suggests that eutrophication and climatic warming may jointly reshape the allocation strategies, performance, and resilience of insect herbivores in Anthropocene ecosystems.

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Nederlandse samenvatting

Waardplant-kwaliteit en omgevingstemperatuur zijn belangrijke omgevingsfactoren voor herbivore insecten, aangezien zij de groei, ontwikkeling en overleving beïnvloeden. Hoewel temperatuur fysiologische processen bij ectotherme insecten versnelt, kan een te kort aan nutriënten in de waardplant de fitheid van insecten beperken. Toch hebben maar weinig studies onderzocht hoe deze twee factoren samen de prestaties van herbivore insecten beïnvloeden. In dit experiment hebben wij de gecombineerde effecten van waardplantstoichiometrie en opgroeitemperatuur experimenteel gekwantificeerd op de larvale groeisnelheid, ontwikkelingstijd en hittetolerantie van volwassen individuen van het landkaartje (Araschnia levana L. 1758). De rupsen werden opgekweekt op grote brandnetel (Urtica dioica L.), die werd gekweekt onder drie bemestingsregimes met verschillende N:P-verhoudingen—om zo de nutriëntenstoichiometrie van de waardplant te veranderen—en onder twee diurnaal fluctuerende temperatuurregimes die respectievelijk omgevingscondities (dag–nacht: 21°C/12°C) en verhoogde temperaturen (dag–nacht: 24°C/16°C) simuleerden. Zowel temperatuur als de stoichiometrie van de waardplant beïnvloedden de prestaties van de vlinders. Opwarming en een gebalanceerde stoichiometrie bevorderden groei en ontwikkeling; onder deze gunstige omstandigheden vertoonden rupsen snelle groei, een kortere ontwikkelingstijd, hogere overleving en een verhoogde hittetolerantie als volwassen vlinder. Een trade-off tussen grootte en leeftijd bij het bereiken van het volwassen stadium—waarbij individuen óf snel volwassen werden bij kleinere lichaamsgrootte, óf langzamer ontwikkelden maar groter werden—werd alleen waargenomen onder omstandigheden die gunstig waren voor groei. Dit suggereert dat onder deze omstandigheden de ontwikkelingstijd de belangrijkste beperkende factor was voor de uiteindelijke lichaamsgrootte van de vlinder. Onze resultaten laten zien dat een disbalans in stoichiometrie in de waardplant kan bepalen hoe herbivore insecten onder opwarmende omgevingsomstandigheden prioriteit geven aan grootte versus leeftijd bij ontwikkeling tot het volwassen stadium, wat ook de hitte tolerantie beïnvloedt. Dit suggereert dat eutrofiëring en klimaatopwarming gezamenlijk de allocatiestrategieën, prestaties en veerkracht van herbivore insecten in ecosystemen van het Antropoceen kunnen hervormen.

Trade‐offs between surviving and thriving: A careful balance of physiological limitations and reproductive effort under thermal stress

David L. Hubert, Ehren J. Bentz, Robert T. Mason — Wed, 13 May 2026 22:21:50 -0700

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Abstract

Balancing survival and reproduction presents a fundamental evolutionary challenge, especially in extreme and unpredictable environments. Thermoregulatory behaviour, in particular, imposes a costly trade-off, as time spent maintaining optimal body temperature precludes other essential activities and forces individuals to balance competing selective pressures. By combining field observations, behavioural assays and gene expression profiling of red-sided garter snakes (Thamnophis sirtalis parietalis), we describe how an ectothermic vertebrate navigates this trade-off in an extreme thermal environment through a combination of finely tuned mechanisms of behavioural and physiological plasticity. Snakes demonstrated remarkably consistent critical thermal limits, with minimal individual variation, suggesting a hard physiological constraint. Males were observed to voluntarily cease seeking mating opportunities and adopt thermoregulatory ‘loafing’ behaviour at body temperatures significantly below the onset of an escape behaviour. Strikingly, however, males that were actively engaged in courtship continued to court females until body temperatures caused the onset of escape behaviour (within 5°C of lethal temperatures) demonstrating context-dependent behavioural plasticity in which the presence of an immediate reproductive opportunity shifts the thermal threshold for behavioural withdrawal. Molecular analyses of multiple tissues revealed rapid, tissue-specific transcriptomic responses activated within 1 h of thermal challenge, well before critical limits were reached. Heat shock proteins were universally upregulated across all tissues under both heat and cold stress, suggesting anticipatory protective mechanisms that support risky behavioural decisions rather than simply responding to thermal damage. Tissue-specific patterns of gene expression reflected functional priorities with liver showing extensive metabolic flexibility, heart maintaining conservative stability, while brain and testis appeared to balance critical functions with stress responses. These findings demonstrate precise thermal reaction norms that integrate behavioural and molecular plasticity to maximize reproductive effort without compromising survival. The narrow margin between behavioural thresholds and lethal limits suggests this system may already be approaching evolutionary constraints. While phenotypic plasticity currently buffers populations against extreme thermal variability, it may paradoxically limit long-term adaptive potential as increasing environmental temperatures further narrow safety margins. Precise thermal decision-making, rapid physiological responses and context-dependent behavioural switching suggest an evolved solution to the problem of balancing competing selective pressures.

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Dynamic rhizosphere C:N:P stoichiometry of plants, soils and microbial biomass under different grazing patterns

Tue, 12 May 2026 03:26:00 -0700

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Abstract

Analysing grassland ecological stoichiometry is crucial for evaluating ecosystem quality and health via energy flow and elemental equilibrium. Grazing is a dominant human activity shaping alpine grasslands on the Qinghai–Tibet Plateau (QTP), yet few studies have used rhizosphere stoichiometry to assess plant–soil–microbe interaction dynamics under different grazing regimes. We compared rhizosphere stoichiometric changes of the degradation indicator Medicago ruthenica and dominant Kobresia humilis under yak grazing (YG), sheep grazing (SG) and mixed grazing (MG) with yak-to-sheep ratios of MG(1:2), MG(1:4) and MG(1:6). MG(1:2) increased total N and reduced total P in M. ruthenica, significantly elevating its N:P ratio; MG(1:4) increased total N and P in K. humilis, lowering its C:N and C:P ratios. Rhizosphere soil of K. humilis showed significantly increased total C and P under MG. For K. humilis, microbial biomass carbon (MBC) and nitrogen (MBN) initially decreased then increased under MG, while microbial biomass phosphorus (MBP) significantly increased across all grazing patterns, with stable plant and microbial biomass N:P ratios. Regulatory pathways differed by species: M. ruthenica affected MBC, MBN and MBP via plant C and N under single grazing, and MBP via soil properties under MG; K. humilis influenced these microbial indices via soil properties and plant C:N:P under single grazing, and soil properties under MG. Our findings reveal trait-dependent stoichiometric responses of key plant species to grazing, advance understanding of rhizosphere plant–soil–microbe interactions in alpine grasslands, and provide a scientific basis for sustainable grazing management on the QTP.

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Wild large herbivores promote plant diversity and functional redundancy by reducing dominance

Sun, 10 May 2026 22:41:28 -0700

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Abstract

Large herbivores can strongly shape plant communities, yet studies report contrasting effects on species richness, and how they affect plant functional diversity remains largely unknown. Moreover, despite important advances in the last years, our mechanistic understanding of herbivore effects on plant communities is still rudimentary. Here, we sampled plant species, vegetation structure and a suite of functional traits in and outside of six large, long-term exclosure experiments (1.6–420 ha; 21–71 years) spanning savanna and thicket biomes in South Africa to quantify wild large herbivore impacts on plant diversity and vegetation structure and identify underlying mechanistic pathways. All sites were inhabited by (nearly) intact herbivore communities. Large herbivores increased total plant species richness and Shannon diversity by reducing dominance and promoting herbaceous species. This was linked to higher plant functional diversity and redundancy. Herbivore effects on diversity were strong in savanna but absent in the thicket. Furthermore, herbivores reduced vegetation height and density in both biomes, but this was unrelated to diversity changes. Plot- and site-scale results were directionally consistent (though significance varied), suggesting that local responses may extend to broader scales. Our results indicate that large herbivores increase plant diversity and functional redundancy in the savanna biome by reducing plant dominance rather than via changes in vegetation structure. These findings suggest that ecosystems with intact herbivore communities may be more resilient and highlight the importance of protecting and restoring large herbivore populations.

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Soil N:P ratio influences species coexistence via nitrogen‐form niche differentiation in alpine grasslands

Sun, 10 May 2026 22:30:53 -0700

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Abstract

Plant species coexistence in nutrient-limited ecosystems is often maintained by niche differentiation in nitrogen (N) uptake. However, how this partitioning responds to changes in nutrient stoichiometry is still poorly understood. We conducted an in situ ¹⁵N labelling experiment in an alpine grassland on the Qinghai–Tibetan Plateau, using NH₄ ⁺, NO₃ ⁻, and glycine tracers under a 6-year factorial N and phosphorus (P) additions (0, 7.5, 15 g N m⁻² year⁻¹; 0, 7.5, 15 g P₂O₅ m⁻² year⁻¹), thereby generating a gradient of soil available N:P ratios ranging from 1.2 to 9.0. Six coexisting plant species were assessed, including dominants (Kobresia pygmaea, Kobresia humilis, Stipa aliena) and subdominants (Poa annua, Potentilla bifurca, Potentilla nivea). All species preferred NH₄ ⁺, but dominant species intensified inorganic N uptake, while subdominants increased glycine use under nutrient additions. Specifically, in dominant species, NO₃ ⁻ uptake increased to ~2.5–5.9 times that in CK, whereas glycine uptake decreased by 75%–78% under high N and P addition levels (N2P2). In contrast, subdominants increased glycine uptake to ~5.8–9.6 times that in CK. This divergence enhanced N-form niche differentiation, which was positively correlated with species evenness in the alpine grassland ecosystem. Niche differentiation was most pronounced when soil available N:P ratios were below ~1.6, corresponding to the half-saturation point of the N-form differentiation curve. Our findings highlight that changes in soil N:P stoichiometry induced by N and P addition drive below-ground N partitioning and promote coexistence through resource complementarity. These results provide a mechanistic basis for biodiversity maintenance in alpine grasslands under nutrient limitation.

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The litter C/N ratio governs the dual role of ectomycorrhizal fungi in decomposition and plant nutrition absorption

Fri, 08 May 2026 23:44:37 -0700

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Abstract

Ectomycorrhizal fungi (EcMF) modulate litter decomposition and facilitate nutrient acquisition through the soil–mycorrhiza–plant pathway. Although litter chemistry has been considered an important factor affecting litter decomposition, how it regulates EcMF-induced decomposition and subsequent plant growth remains unclear. Using a microcosm experiment with five litter types, we assessed decomposition rates, carbon (C) and nitrogen (N) loss, microbial biomass, enzyme activities and plant growth under ectomycorrhizal and non-ectomycorrhizal seedlings. Results indicated that effects of EcMF on litter decomposition were litter-specific and time-dependent. After 120 days, EcMF enhanced decomposition of low C/N litters (Carex breviculmis, Lindera glauca and Liquidambar formosana) by 13%–28%, but suppressed that of high C/N litters (Quercus acutissima and Pinus massoniana) by 19%–20%. Initially (30 days), EcMF inhibited low C/N litter decomposition, later shifting to promotion, whereas high C/N litter decomposition was consistently suppressed. Correlation analysis revealed that the hyphal effects on decomposition correlated negatively with litter stage C/N ratio. EcMF significantly increased plant N concentration and biomass under low C/N litters (biomass increased by 20%–30%), but only marginally enhanced biomass under high C/N litters (14%–16%) without improving N concentration. Partial least squares path modelling revealed that EcMF promoted C and N release from low C/N litter, thereby increasing N availability and plant growth. Even under high C/N conditions, EcMF directly supported plant growth despite suppressed decomposition. These findings underscore the dual roles of EcMF, which are regulated by litter C/N ratio, in mediating decomposition and plant nutrient acquisition, highlighting the importance of litter–microbe interactions in forest nutrient cycling and productivity.

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Decreasing water availability reduces productivity in Swiss forests along an altitudinal gradient

Fri, 08 May 2026 00:00:00 -0700

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Abstract

Forests are one of the most important terrestrial carbon sinks, but are increasingly under pressure due to drought, heat and the occurrence of extreme events. There are opposing longer term trends for European forest growth reported, and severe drought and disturbance events additionally impact forest ecosystems, so that the overall trend of forest productivity is uncertain. Thirty years of harmonized forest monitoring at 18 forest sites along an altitudinal gradient in Switzerland provides a good basis for assessing the effects of climate change on forest conditions. We found a decreasing trend of forest productivity (basal area index and net carbon uptake by growth), particularly pronounced since 2015 across all altitudinal ranges, age classes and species, which could not solely be attributed to stand density and ageing of the forest, but also to soil water availability and nitrogen deposition. The growth rate of trees, as well as the ingrowth rate, were hereby the most important factors explaining the overall forest productivity. At a given stand density, forest productivity was lower in recent years compared to earlier decades. Overall, our results indicate a decreasing stand-level growth trend irrespective of site conditions and stand structure. This 30-year declining trend can be partly attributed to water and nitrogen availability, and points to a decreasing growth capacity of the forest sites that is the long-term potential of a site to sustain tree growth. The pivotal role of water availability for sustainable forest production and the long-term effect of drought years on forest vitality urges us to rethink the adaptability of forests in view of the increasing frequency of drought and heat periods predicted for the future.

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Wind, waves, wing loading and the flight energetics of giant petrels

Madeline E. Hallet, Richard A. Phillips, Ian J. Maywar, Lesley H. Thorne — Thu, 07 May 2026 21:41:53 -0700

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Abstract

Wind is a major factor driving seabird movement and energetics, the effects of which are modulated by morphology. Developments in tagging technology now make it possible to test predictions from aerodynamic theory about the effects of wind on flight performance in free-ranging birds. Waves are also thought to have a strong influence on seabird movement but have received less attention. We investigated the interplay between wind, waves, and morphology and tested predictions of flight theory in giant petrels (Macronectes spp.), which show greater sexual size dimorphism than any other seabird. We quantified flapping rates as a proxy of energy expenditure using accelerometers deployed on northern giant petrels (M. halli; n = 45) and southern giant petrels (M. giganteus; n = 48) breeding at Bird Island, South Georgia in 2022 and 2023. Wind and waves experienced by birds tracked with Global Positioning System (GPS) loggers were integrated with ERA5 reanalysis data to assess how flapping rates and ground speeds, respectively, were influenced by wind and waves. Using generalized additive mixed models, we predicted the spatial distribution of suitable habitat for soaring based on wind and wave conditions. Both wind and waves strongly influenced flight energetics; flapping rates decreased with increasing wind speed and swell height in all species and sexes. Together, wind and waves allowed giant petrels to reduce flapping rates by 76% to 91%. Wind also influenced the speed of travel; ground speed increased with wind speed in tail- and crosswinds, but generally decreased with wind speed in headwinds. Male giant petrels had higher wing loadings, and as predicted by flight theory, required higher air speeds for soaring flight and had higher flapping rates than females. Potential soaring habitat was much more limited for male than for female giant petrels, suggesting that differences in flight energetics between sexes may contribute to sexual segregation in foraging areas. Our results demonstrate how morphology, wind and waves combine to influence the flight energetics of giant petrels. Understanding the interactions among these factors is central to understanding environmental drivers of seabird distribution and to predicting responses to continued climate change.

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Hummingbird interaction niche packing is influenced by species richness and resource availability in the southern tropical Andes

Bryan G. Rojas, Carlos Iván Espinosa, Catherine H. Graham, Boris A. Tinoco — Wed, 06 May 2026 09:41:03 -0700

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Abstract

Niche partitioning is often considered an important mechanism promoting species co-occurrence in species-rich communities. As species richness increases, niche partitioning may lead to different niche structures, including increased packing of species niches when the community niche space remains unchanged, or expansion of the community niche spaces as additional species are incorporated. In hummingbird assemblages, competitive interactions can strongly influence niche partitioning, and competition often is influenced by resource availability and bill morphology. However, it remains unclear whether resource availability and morphological traits influence hummingbird co-occurrence through niche expansion or packing. Here, we used the interaction niche—which quantifies hummingbird resource niches in terms of plant traits on which the birds forage—to evaluate whether interaction niche packing or expansion characterizes hummingbird co-occurrence in a high-Andean montane forest in southern Ecuador. We found that when hummingbird species richness was high, interaction niche packing and not expansion predominated and was characterized by greater niche overlap among species. However, niche overlap was greater when flower resource availability was low and lower when co-occurring hummingbirds had divergent bill lengths. These results highlight the importance of morphological traits and floral resource availability on interaction niche overlap in Andean hummingbird species, and how this, in turn, defines patterns of species co-occurrence. Further, these findings reveal that the interaction niche offers a powerful tool to explore the ecological processes potentially leading to species co-occurrence.

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Resumen

La partición de nicho es considerado un mecanismo importante que promueve la coocurrencia de especies en comunidades con alta riqueza de especies. Cuando la riqueza incrementa, la partición de nicho puede conducir a diferentes formas de estructuración del nicho, incluyendo el empaquetamiento de nicho cuando el espacio de nicho de la comunidad se mantiene constante, o a la expansión de nicho cuando el espacio de la comunidad crece. En ensamblajes de colibríes, la competencia puede tener una fuerte influencia en la partición de nicho, a su vez la competencia está influenciada por la disponibilidad de recursos y la morfología del pico. Sin embargo, no está claro si la disponibilidad de recursos y los rasgos morfológicos influyen en la coocurrencia de colibríes por medio de la expansión o el empaquetamiento de nicho. En este estudio utilizamos el nicho de interacción, que cuantifica el nicho del recurso de los colibríes en términos de los rasgos de plantas que utilizan los colibríes, para evaluar si la coocurrencia de colibríes en los bosques montanos altoandinos del sur del Ecuador es caracterizada por el empaquetamiento o la expansión del nicho de interacción de los colibríes. Encontramos que cuando la riqueza de especies es alta, el empaquetamiento de nicho de interacción, y no la expansión de nicho, predominó y se caracterizó por un mayor solapamiento de nicho entre especies. No obstante, el solapamiento del nicho fue mayor cuando la disponibilidad de recursos florales fue menor y fue menor cuando los colibríes que coocurrían presentaban una mayor divergencia en la longitud del pico. Estos resultados resaltan la importancia del efecto de rasgos morfológicos y de la disponibilidad de recursos florales en el solapamiento del nicho de interacción en las especies de colibríes Andinos, y como esto define, a su vez, los patrones de coocurrencia de especies. Adicionalmente, estos hallazgos indican que el nicho de interacción representa una herramienta útil para explorar los procesos ecológicos que potencialmente conducen a la coocurrencia de especies.

Coping with change: Interactive effects of anthropogenic change influence the breeding success and survival of a desert‐dwelling cooperative breeder

Tue, 05 May 2026 23:43:12 -0700

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Abstract

Habitat modification and climate change are major threats to biodiversity. Using 38 years of data (1985–2023), we examined their combined influence on a desert-dwelling cooperative breeder's reproductive success and projected the likely magnitude of future effects of these threats under two climate scenarios for the end of the century (2100). In natural habitats, rainfall increases reproductive success, while extreme temperatures reduce survival. Human-modified habitats buffer against climate extremes, resulting in higher reproductive success even in dry and hot conditions.

Future projections indicate likely declines in lifetime reproductive success in natural habitats, but the same projected declines are not observed in modified habitats, which may offer temporary refugia against climate effects.

In both habitats, larger social groups had higher reproductive success and survival rates, highlighting the important role of helpers in cooperatively breeding species.

Our findings highlight the need to assess multiple anthropogenic factors to fully understand their impact on species' fitness and the importance of long-term datasets in addressing the complex relationship between the multiple drivers of anthropogenic change.

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Resumen

La modificación de hábitats y el cambio climático son dos de las principales amenazas para la biodiversidad. En este estudio utilizamos 38 años (1985–2023) de datos para examinar la influencia combinada de estos dos factores sobre el éxito reproductor y la supervivencia de una especie con cría cooperativa de regiones desérticas. También proyectamos la magnitud potencial de esas amenazas en dos escenarios climáticos para el final del siglo (2100). En hábitats naturales la lluvia mejora el éxito reproductor, mientras que las temperaturas extremas reducen la supervivencia. Los hábitats antropogénicamente modificados mitigan los efectos de los extremos climáticos, resultando en un mayor éxito reproductor incluso en condiciones de sequía y altas temperaturas. Las proyecciones a futuro muestran posibles disminuciones en el éxito reproductor a largo plazo de los individuos de hábitats naturales, mientras que estas tendencias no se observan en los hábitats modificados, señalándolos como un posible refugio climático temporal. En ambos hábitats, grupos más grandes tuvieron un mayor éxito reproductor y mejores tasas de supervivencia, destacando la importancia de los ayudantes en las especies con cría cooperativa. Nuestros resultados resaltan la importancia de incluir múltiples factores de cambio antropogénico para comprender su impacto en el fitness de las especies, así como la importancia de las bases de datos a largo plazo para resolver las complejas relaciones de los múltiples agentes de cambio antropogénico.

Shrub encroachment influences root traits and mycorrhization in subalpine grasslands

Mon, 04 May 2026 22:14:29 -0700

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Abstract

Shrub encroachment into grasslands modifies ecosystem functions, species composition and soil properties. However, knowledge about its detailed below-ground effects and specifically on concurrent changes in root traits and mycorrhizal associations is missing. We studied the effects of shrub encroachment on the herbaceous and the whole subalpine grassland community (i.e. including herbaceous and shrub species) in the Austrian Alps. We analysed changes in root traits and mycorrhizal associations, and their interactions, along two gradients of shrub cover, one dominated by deciduous and the other by evergreen dwarf shrubs. As shrub cover increased, in the herbaceous community root tissue density (RTD) increased, while specific root length (SRL), arbuscular mycorrhizal fungi (AMF) colonization and arbuscule abundance, where nutrient exchange occurs, all decreased. In the whole community, RTD unexpectedly decreased with shrub cover, as shrubs showed lower RTD than neighbouring herbaceous swards. The decrease in RTD, SRL, root diameter and AMF colonization was only compensated by a slight increase in the relative abundance of ericoid mycorrhizal fungi (ErM). Shrub encroachment in subalpine grasslands significantly modifies root traits and mycorrhizal associations. Herbaceous plants shift towards more conservative root strategies with increasing shrub cover. Concurrently, the whole community shows compensation between ErM and AMF colonization, while root resistance and soil exploration ability decrease. Our results suggest that changes along a gradient of shrub cover concern individual traits or trait–trait interactions, rather than following the ‘root economics space’ framework focused primarily on AMF.

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Plasma insulin‐like growth‐factor 1 (IGF‐1) concentrations predict early life‐history traits in a wild mammal

Fri, 01 May 2026 23:44:41 -0700

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Abstract

The hormone insulin-like growth factor 1 (IGF-1) is a key player in the insulin/IGF signalling (IIS) pathway. Extensive biogerontological research demonstrates that this evolutionarily conserved nutrient-sensing pathway plays a causal role in the regulation of growth, reproduction and longevity under laboratory conditions. However, its potential role as a mediator of adaptive life-history variation in highly variable natural environments remains unclear. We measured IGF-1 concentrations in blood samples from approximately 4-month-old wild Soay sheep lambs (n = 669), collected over nine summers. We tested whether IGF-1 (i) was positively related to proxies of resource availability, (ii) was associated with morphological traits measured concurrently and (iii) predicted subsequent fitness-related traits. Plasma IGF-1 concentrations were higher in males compared to females and positively associated with measures of resource availability in both sexes. IGF-1 was lower in years of high population density when per capita food availability was reduced; in twin lambs who have fewer available resources compared to singletons; and in lambs born to young and old mothers, who have poor maternal provisioning compared to mothers of intermediate age. Higher IGF-1 concentrations in summer were associated with higher body mass, faster post-natal somatic growth and increased skeletal size, measured at the same time. These associations were observed after statistically controlling for our proxies of resource availability. Lambs with higher summer IGF-1 concentrations were more likely to survive their first winter and reproduce the following spring. The association between IGF-1 and reproduction was present after accounting for our resource availability proxies, whereas the association with first-winter survival was not. The association between summer IGF-1 and reproduction was explained by positive associations with summer body mass. Our study reveals population-level phenotypic plasticity in circulating IGF-1. We found IGF-1 to be positively associated with key morphological traits and to positively predict fitness traits in early life. These findings highlight IGF-1 as a candidate physiological mechanism underpinning plastic responses to variation in food availability and influencing life-history traits in a wild mammal.

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Bee community assembly is regulated by functional traits in pristine tropical forest environments

Thu, 30 Apr 2026 03:12:44 -0700

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Abstract

Understanding the drivers of bee beta diversity across pristine environments in the Amazon is critical for ensuring biodiversity conservation, restoration, sustainable land use planning and economic development. Here, we aim to reveal the patterns of among-site variation in bee communities between pristine open habitats and pristine forest formations in the Amazon using standardized bee surveys across sites and trait-based analyses (body size, sociality, nesting, buzz pollination and colour). We quantified dissimilarity patterns and evaluated environmental filtering effects to test (1) whether functional diversity can better predict bee beta diversity than taxonomic diversity can and (2) whether environmental filtering determines the predominant bee traits for each environment. Our results revealed a high overall beta diversity across all pristine environments, which was primarily driven by species and functional trait turnover. Compared to taxonomic metrics, functional beta diversity better captured among-site variation, highlighting distinct ecological filtering between habitats to select different sets of traits. A portion of open habitat communities was functionally nested within forest assemblages, suggesting that forests may serve as species reservoirs for open habitats. Forests supported a richer taxonomic and functional bee assemblage, while open habitat communities exhibited specialized traits, including solitary behaviour, exposed nesting, dark coloration and buzz pollination. These findings highlight the importance of landscape heterogeneity and trait-based approaches, which should be incorporated into environmental management, restoration and biodiversity offset plans. From a conservation perspective, our results stress the need to maintain open habitat patches (regardless of their size), which must remain embedded within a forest matrix. With respect to restoration, we show that restoration of open habitats should consider the recovery of adjacent forest habitats to support ecological functionality. Integrated efforts are needed to recognize landscape heterogeneity as a fundamental component of ecological resilience in the Amazon. Incorporation of functional beta diversity into conservation and restoration planning increases the maintenance in the provision of ecosystem services and environmental resilience in Amazonian landscapes.

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Resumo

Compreender a beta diversidade de abelhas em ambientes primários na Amazônia é fundamental para assegurar a conservação da biodiversidade, a restauração, o planejamento sustentável do uso da terra e o desenvolvimento econômico. Nesse estudo, buscamos revelar os padrões de beta diversidade entre comunidades de abelhas em áreas primárias de vegetação aberta e florestas primarias na Amazônia. Utilizamos amostragens padronizadas em diferentes áreas e análises baseadas em traços funcionais (tamanho corporal, socialidade, nidificação, buzz pollination e coloração). Quantificamos os padrões de dissimilaridade e avaliamos os efeitos do filtro ambiental para testar (1) se a diversidade funcional pode predizer melhor a beta diversidade de abelhas do que a diversidade taxonômica e (2) se a filtragem ambiental determina os traços predominantes das abelhas em cada ambiente. Encontramos uma alta beta diversidade em todos os ambientes primários, impulsionada principalmente pela substituição (turnover) de espécies e de traços funcionais. Em comparação às métricas taxonômicas, a beta diversidade funcional capturou melhor a variação entre locais, evidenciando distintos processos de filtragem ecológica entre habitats que selecionam diferentes conjuntos de traços. Parte das comunidades presentes em áreas abertas mostrou-se funcionalmente aninhada às comunidades de áreas florestais, sugerindo que as florestas podem atuar como reservatórios de espécies para os habitats abertos. As florestas sustentaram comunidades com maior riqueza, taxonômica e funcional, enquanto as comunidades de habitats abertos apresentaram traços especializados, incluindo comportamento solitário, nidificação exposta, coloração escura e polinização por vibração. Destacamos a importância da heterogeneidade da paisagem e de abordagens baseadas em traços, que devem ser incorporadas ao manejo ambiental, a estratégias de restauração e aos planos de compensação de biodiversidade. Sob a perspectiva da conservação, nossos resultados ressaltam a necessidade de manter manchas de habitats abertos (independentemente de seu tamanho), que devem permanecer inseridas em uma matriz florestal. No contexto da restauração, mostramos que a recuperação de habitats abertos deve considerar a restauração de áreas florestais adjacentes para sustentar a funcionalidade ecológica. A incorporação da beta diversidade funcional no planejamento da conservação e da restauração contribui para a manutenção da provisão de serviços ecossistêmicos e da resiliência ambiental das diferentes paisagens amazônicas.

Lichen bleaching as a response to long‐term experimental warming in the High Arctic

Jiří Šubrt, Mariana García Criado, Kevin K. Newsham, Claudia Colesie — Tue, 28 Apr 2026 22:48:47 -0700

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Abstract

Lichens are an important component of Arctic ecosystems. Studies have indicated a decline in the abundance of Arctic lichens during recent decades, which is often attributed to competitive pressure from vascular plants. However, the direct effects of warming on the lichen symbiosis have rarely been explored, particularly in the High Arctic, where shrubification is less pronounced than in the Low Arctic, and where warming might hence have more direct effects on the growth and survival of lichens. Here, we investigated the physiological responses of Cetrariella delisei, a widespread circumpolar lichen species, to almost a decade of experimental warming with open-top chambers. We found that C. delisei physiologically deteriorated in response to the warming treatment, with the myco- and photobiont differing in their sensitivities to warming. Symbiotic deterioration was manifested in a 2.4-fold reduction in net photosynthesis, an approximate doubling in maximum respiration rate, and a loss of 60% of the algal photobiont and a 30% decline in chlorophyll concentration, which caused bleaching of the lichen thallus. These changes resulted in a negative thallus carbon balance and a loss of photosynthetic capacity at low temperatures. Our findings, which advance mechanistic understanding of symbiotic breakdown and lichen bleaching, shed new light on the physiological impacts of warming on polar lichens. We show that photobionts have high sensitivity to increases in mean and maximum daily summertime air temperatures of 1 and 4°C, respectively. These are early warning signals that the mat-forming lichen C. delisei is under threat in the rapidly warming Arctic.

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Abstrakt (Czech)

Lišejníky jsou důležitou součástí arktických ekosystémů. Předchozí studie naznačují pokles v množství arktických lišejníků během posledních dekád, a toto je z velké části přisuzováno ke konkurenčnímu tlaku od cévnatých rostlin. Přímé účinky oteplování na lišejníkovou symbiózu však byly dosud zkoumány jen zřídka, zejména ve vysoké Arktidě, kde je proces křovinatění méně výrazný než v nízké Arktidě a kde by proto oteplování mohlo mít přímější dopady na růst a přežití lišejníků. Zde jsme zkoumali fyziologické reakce Cetrariella delisei, hojně rozšířeného polárního lišejníku, na téměř dekádu experimentálního oteplování s pomocí kultivačních komor (open-top-chambers). Zjistili jsme, že C. delisei fyziologicky deterioroval v reakci na zvýšenou teplotu, přičemž myko- a fotobiont se lišily ve své citlivosti vůči oteplování. Deteriorace symbiózy se projevila 2,4násobným snížením fotosyntézy, přibližným zdvojnásobením maximální rychlosti respirace, ztrátou 60% algálního fotobiontu a 30% poklesem koncentrace chlorofylu, což způsobilo bělení stélky (lichen bleaching). Tyto změny vedly k negativní uhlíkové bilanci stélky a ztrátě kapacity fotosyntetizovat při nízkých teplotách. Tato zjištění, která prohlubují mechanistické pochopení rozpadu symbiózy a bělení lišejníků, přinášejí nové poznatky o fyziologických dopadech oteplování na polární lišejníky. Znázorňujeme, že fotobiont vykazuje vysokou citlivost vůči nárůstu průměrných a maximálních denních letních teplot vzduchu o 1–4°C. Toto může znamenat včasný varovný signál, že lišejník C. delisei je ohrožen na rychle oteplující se Arktidě.

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Resumen (Spanish)

Los líquenes son un componente importante de los ecosistemas árticos. Estudios previos han mostrado una disminución en la abundancia de líquenes árticos durante las últimas décadas, lo que se atribuye frecuentemente a la presión competitiva por parte de las plantas vasculares. Sin embargo, los efectos directos del calentamiento global sobre la simbiosis liquénica apenas han sido explorados, particularmente en las zonas árticas del norte, donde la arbustificación es menos pronunciada que en las zonas sur del Ártico, y donde el aumento de temperaturas podría, por tanto, tener efectos más directos sobre el crecimiento y la supervivencia de los líquenes. En este estudio, investigamos las respuestas fisiológicas de Cetrariella delisei, una especie de líquen circumpolar ampliamente distribuida, tras casi una década de calentamiento experimental mediante cámaras de techo abierto. Encontramos que C. delisei se deterioró fisiológicamente en respuesta al aumento de temperaturas, y que el micobionte y el fotobionte difieren en su sensibilidad al calentamiento. El deterioro simbiótico se manifestó en una reducción de la fotosíntesis neta de 2,4 veces, una duplicación de la tasa máxima de respiración, una pérdida del 60% del fotobionte de alga, y una disminución del 30% en la concentración de clorofila, lo que causó el blanqueamiento del talo (‘lichen bleaching’). Estos cambios resultaron en un balance de carbono negativo del talo y una pérdida de la capacidad fotosintética a bajas temperaturas. Nuestros hallazgos, que contribuyen al entendimiento mecanístico de la ruptura simbiótica y el blanqueamiento de líquenes, muestran los posibles impactos fisiológicos del calentamiento en los líquenes polares. Mostramos que los fotobiontes presentan una alta sensibilidad ante aumentos de las temperaturas medias y máximas diarias del aire en verano de 1 y 4°C, respectivamente. Por lo tanto, estos resultados indican una señal de alerta temprana de que el líquen C. delisei se podría encontrar amenazado en un Ártico que se calienta rápidamente.

Increased energetic cost of movement reduces reproductive output in zebrafish at different temperatures and water flow rates

Miki Jahn, Frank Seebacher — Wed, 15 Apr 2026 00:02:16 -0700

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Abstract

Locomotion consumes a large proportion of individual energy budgets and may impose energetic constraints on other fitness-related traits particularly under variable environmental conditions. Here, we tested whether increased energetic cost of transport (CoT) leads to reduced movement to minimise cost, and impacts reproductive investment and success at different temperatures and water flow conditions. CoT integrated across a range of speeds within individuals (∫CoT) was greater in fish acclimated to 30°C compared with 24°C, but acclimation to water flow did not alter ∫CoT. When tested in familiar groups, voluntary speed increased with increasing ∫CoT at 30°C, but nearest neighbour distance within groups did not change with individual differences in ∫CoT. Reproductive investment was lowest in fish acclimated to 30°C and flowing water. Increasing ∫CoT was negatively correlated with reproductive investment when fish were acclimated in still water. Egg quality and offspring survival decreased with acclimation to 30°C and water flow, compared with 24°C and still water, respectively. We show that reproductive investment was lowest under energetically demanding environmental conditions, and that energetic cost of locomotion can constrain reproduction. These responses can explain how environmental variation such as altered river flows, global warming and even habitat fragmentation can reduce fitness and potentially impact populations.

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Diet, phenology and body size shape nutrient release by songbirds

Linsey Chen, Alexander S. Flecker, Ethan S. Duvall — Fri, 13 Feb 2026 01:59:57 -0800

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Abstract

Animals can dramatically alter ecosystem structure and function through the cycling and transport of nutrients in their waste. While birds are particularly capable of influencing nutrient cycles due to their high mobility, abundance, metabolism and functional diversity, the factors shaping variation in nutrient release among birds remain poorly understood. We examined how trophic position, phenology and body size shape the release of carbon (C), nitrogen (N) and phosphorus (P) in the waste of a diverse assemblage of songbirds. We analysed waste samples (reflecting excretion and egestion) from 151 individual songbirds (31 species) at a migratory stopover site during one spring and one fall season in upstate New York, USA. Trophic position, represented by δ¹⁵N in waste, correlated positively with %N and negatively with C:P. Waste stoichiometry also differed between seasons with higher %N and lower C:N in spring compared to fall as birds shifted their diets from N-rich insects in spring to C-rich fruits and seeds in fall. Birds in the fall exhibited increased fattiness, and body size had the strongest influence on C, N and C:N release during this season, suggesting that fat accumulation for energy storage may shape nutrient excretion prior to migration. However, the effects of body mass and its interactions with season and trophic position were complex. Ultimately, trophic position, phenology and body mass together helped explain variation in nutrient release among songbirds. Future research may leverage this information to further explore how migratory songbirds influence stopover habitats and other ecosystems via contributions to nutrient cycling.

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Temporal community change in stream ecosystems varies by assemblage across US climates

Tue, 23 Dec 2025 04:31:30 -0800

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Abstract

Ecosystem properties are temporally dynamic. Temporal variability has been shown to decrease with increasing levels of biological organization (i.e. from population to community and ecosystem levels). However, patterns of temporal variability in community properties across assemblages are poorly understood. To address this gap, we used biotic sampling data for three distinct groups—algae, macroinvertebrate and fish—from the National Ecological Observatory Network wadeable stream sites, which span a broad hydroclimatic gradient across the conterminous United States, Alaska and Puerto Rico. We examined whether total temporal beta-diversity differed among assemblages and quantified the relative contributions of two mechanisms generating community dissimilarity: balanced variation (i.e. species replacing each other) and abundance gradient (i.e. species fluctuating in abundance synchronously). We also investigated whether the temporal scale of variation (seasonal vs. interannual) differed among assemblages and assessed patterns across a broad hydroclimatic gradient. We found that total beta-diversity was lower for fish assemblages, with average algae and macroinvertebrate temporal beta-diversity values 30% greater than average fish values. Algae and macroinvertebrates were more characterized by the balanced variation component, while fish were more characterized by abundance gradients. The temporal scale of variation did not vary among assemblages, with all three assemblages tending to vary mostly at the interannual time scale. Finally, we found that fish were more responsive to precipitation and discharge variability than algae and macroinvertebrates, but temperature variability and climate class did not drive beta-diversity patterns. Our work highlights that beta-diversity patterns and the processes behind them differ across assemblages, with systematic variation in body size and generation times likely explaining observed differences between algae, macroinvertebrates and fishes. Understanding how and why different groups show different levels of temporal stability is critical to anticipating ecological responses of aquatic communities to increasingly altered environmental regimes.

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Soil and microbial responses to wild ungulate trampling depend more on ecosystem type than trampling severity

G. Adam Meyer, Shawn J. Leroux, Kathryn E. Hargan, Niels van Miltenburg — Wed, 30 Jul 2025 01:58:28 -0700

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Abstract

Physical trampling is a ubiquitous activity of walking vertebrates, but is poorly understood as a mechanism impacting biogeochemical cycling in soil. Lack of detailed knowledge of soil abiotic–biotic interactions underlying trampling effects, and the primary sources of heterogeneity in these effects, limit our ability to predict ecosystem-level consequences of ongoing population changes in large animals. We conducted a summer field study of moose trampling effects on soil properties and nitrogen cycling using natural moose trails in boreal forest and heath barren ecosystems on the island of Newfoundland, Canada. We tested the extent to which trampling effects on soil abiotic properties, microbes, and nitrogen cycling depend on local trampling severity, and/or ecosystem type. Using structural equation models, we further tested whether trampling effects on soil nitrogen mineralization occurred via indirect interaction chains mediated by soil abiotic and microbial properties. Finally, we tested whether trampling modifies plot-scale controls on net nitrogen mineralization. Trampling effects on the soil environment, substrate, and microbial properties depended on ecosystem type, but rarely on trampling severity. Trampling effects were of consistently greater magnitude in heath than in forest. Further, trampling effects on organic matter content, pH, moisture, microbial abundance, and microbial community composition were qualitatively different between forest and heath ecosystems. Trampling severity increased the magnitude of some trampling effects in heath, but did not impact the direction of the effects and did not significantly impact any trampling effects in forest. Trampling indirect effects on soil microbes were ecosystem-dependent but did not alter net N mineralization rates. In forest, trampling did not shift N mineralization rates via any indirect interaction chains, but modified relationships between N mineralization and other soil physical and microbial properties. In heath, multiple opposing interaction chains resulted in no net shift in N mineralization rates, and most relationships between diverse soil properties and N mineralization were not modified by trampling. Overall, our results disentangle complex abiotic–biotic interactions underlying megafauna effects on ecosystem functioning. These insights pave the way for better integration of animal consumptive and non-consumptive mechanisms into biogeochemical models, as well as prediction of trampling effects over landscapes.

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Shared leadership can promote success in collaborative research networks in ecology

Mon, 21 Jul 2025 00:00:00 -0700

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Abstract

While collaborative science is becoming the norm in ecology, many ecologists participating in collaborations are less aware of the body of research that studies the processes by which collaborative teams organize and communicate. Here, we discuss how we successfully used a shared leadership model in the Dry Rivers Research Coordination Network. We discuss how this model promoted our success in different stages of the project, using the Tuckman model of team development: forming, storming, norming, performing and adjourning. Shared leadership in the forming phase helped us recruit a diverse membership from different scientific disciplines. In the storming and norming phases, shared leadership was especially useful in ensuring that all voices were heard in establishing group norms that promoted adhesion among and investment by RCN members. Shared leadership in the performing phase was crucial in providing opportunities for early career members to lead projects, and in the adjourning phase we reflected upon our entire collaboration to identify that shared leadership was crucial to our success, generating the thesis for this commentary. It is our hope that others may find this discussion of our experience in implementing a shared leadership model useful in developing their own fruitful collaborations.

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Facilitating macrosystem biology with organismal‐scale airborne remote sensing: Challenges and opportunities

Mon, 09 Jun 2025 01:43:51 -0700

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Abstract

Emergent ecosystem properties, such as population and trait distributions, biodiversity and energy and water fluxes, occur because of the dynamic interactions of individuals in their environment. Remote sensing, where image data is collected over large areas, can provide information about individual organisms that reveals important ecosystem patterns and processes that are critical for macrosystems scale biology. In this review, we summarize the primary challenges of conducting organismal-scale remote sensing, such as the detection, delineation and characterization of organisms including trees, birds and mammals. For each, we highlight existing and emerging solutions that directly address these challenges. Algorithmic advancements in the realm of deep learning are one solution to addressing the challenges of limited field data, particularly for applications that require models to generalize across ecosystems and transfer to new environments and sensors. Ecological knowledge can be integrated into novel data processing pipelines such as characterizing organisms from a different perspective, translating ecological rules to mathematical expressions and casting uncertainty. To realize the potential of organismal remote sensing requires deliberate interdisciplinary collaboration with the shared goal of developing methods to produce useful ecological data products.

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Scaling from microsite to landscape to resolve litter decomposition dynamics in globally extensive drylands

Wed, 26 Mar 2025 01:59:23 -0700

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Abstract

Decomposition is the transformation of dead organic matter into its inorganic constituents. In most biomes, decomposition rates can be accurately predicted with simple mathematical models, but these models have long under-predicted decomposition in globally extensive drylands. We posit that the exposed surface conditions characteristic of drylands make litter decomposition uniquely subject to microsite-specific environmental controls and spatially variable microbial communities. As such, decomposition in dryland ecosystems—which are characterized by extremes in temporal heterogeneity of climate conditions and spatial heterogeneity of vegetation cover with corresponding microclimate variability—is a prime example of a macrosystems process that can be addressed by merging field data with new predictive process models operating across a hierarchical continuum of spatial scales and process resolutions. A macrosystems approach offers promise to reconcile model-measurement discrepancies by integrating observations and experiments across multiple scales, from microsites (e.g. shrub sub-canopy or intercanopy) to regions (e.g. across a 100s of km² study site with complex topography, precipitation and temperature) and ultimately to a continental perspective (e.g. North American drylands). Recent developments in technology and data availability position the scientific community to integrate laboratory, field, modelling and remote sensing approaches across a hierarchical range of scales to capture the spatiotemporal distribution of litter and environmental conditions needed to predict decay dynamics at the micro-to-macroscale. This multi-scale approach promises a path forward to resolving a longstanding disconnect between measured data and modelled processes in dryland litter decomposition. Dryland litter decomposition presents an excellent case study for resolving spatially and temporally complex biogeochemical dynamics through a hierarchical, multidisciplinary macrosystems approach. We focus on dryland litter decomposition, but the hierarchical, multidisciplinary macrosystems approach we outline shows great potential for resolving other spatially and temporally complex biogeochemical processes across a wide range of ecosystems.

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Resumen

La descomposición es la transformación de material orgánica muerta en sus componentes inorgánicos. En la mayoría de los biomas las tasas de descomposición pueden ser predichas con certeza utilizando modelos matemáticos simples, sin embargo, estos modelos han subestimado la descomposición en ecosistemas áridos y semiáridos, los cuales cubren una basta área del planeta. Nosotros proponemos que las zonas de superficie expuestas o desprovistas de vegetación, que son características de los ecosistemas áridos y semiáridos, hacen que la descomposición del mantillo esté sujeta de manera única a controles ambientales específicos de micrositios y a comunidades microbianas que varían espacialmente. Así, la descomposición en ecosistemas áridos y semiáridos—caracterizados por una extrema heterogeneidad temporal de condiciones climáticas, así como una gran heterogeneidad espacial de cobertura vegetal, misma que genera variaciones microclimáticas—es un ejemplo de un proceso macroecosistémico que puede abordarse combinando información de campo con nuevos modelos predictivos que operan en un continuo jerárquico de escalas espaciales y resolución de procesos. Un enfoque macroecosistémico ofrece la primicia de reconciliar las discrepancias entre mediciones y modelos al integrar observaciones y experimentos a través de diferentes escalas, desde los micrositios (p.ej., bajo el dosel de arbustos, y en áreas entre doseles) hasta regiones (p.ej., en sitios de estudio de cientos de km² con patrones complejos de topografía, precipitación, y temperatura) y, en última instancia, desde una perspectiva continental (p.ej., ecosistemas áridos y semiáridos de Norteamerica). Los avances recientes en tecnología y disponibilidad de datos permiten a la comunidad científica integrar métodos de laboratorio, campo, modelación, y de teledetección a lo largo de un rango jerárquico de escalas para capturar la distribución espaciotemporal del mantillo y las condiciones ambientales necesarias para predecir la dinámica de su decaimiento desde la microescala hasta la macroescala. Este enfoque multi-escala ofrece una vía para resolver la desconexión entre datos recabados en campo y modelados sobre descomposición de mantillo. Así, la descomposición del mantillo en ecosistemas áridos y semiáridos representa un excelente caso de estudio para resolver, espacial y temporalmente, dinámicas biogeoquímicas complejas a través de un enfoque jerárquico, multidisciplinario, y macroecosistémico. Además, aunque nosotros nos enfocamos en las tasas de descomposición de ecosistemas áridos y semiáridos, nuestro enfoque jerárquico, multidisciplinario, y macroecosistémico muestra un gran potencial para resolver otros procesos biogeoquímicos complejos en términos espaciales y temporales en una amplia gama de ecosistemas.

摘要

分解是将凋落的有机物质转化为无机成分的过程。在大多数生物群落中，分解作用可以通过简单的数学模型成功预测，但这些模型长期以来低估了全球广泛分布的旱地的分解作用。我们认为，旱地特有的裸露地表条件使凋落物分解易受到微域特定环境条件和空间变化的微生物群落的影响。因此，旱地生态系统的分解作用(以极度异质的气候条件和空间异质的植被覆盖以及相应的微气候为特征)是宏观系统过程的一个典型例子，该过程需要将现场数据与新的旱地分解过程预测模型相结合，跨越一系列空间尺度和过程尺度。宏观系统研究方法有望通过整合多尺度的观测和实验来调和差异，从微域(例如，灌木亚冠层或冠层间)到区域(例如，具有复杂地形、降水和温度的数百平方公里的研究地点)并最终到大空间尺度(例如，北美旱地)来开展研究。最新的技术和数据可用性的进展，为此类研究提供了多尺度范围内的实验、现场、建模和遥感方法，这些方法有可能捕捉凋落物的分布和环境条件，来预测从微观到宏观尺度的分解动态。该方法有望解决旱地分解中实地测量数据和建模数据之间长期存在的脱节问题。旱地凋落物分解提供了一个极好的案例研究，通过分层、多学科、宏观系统方法研究生物地球化学动态的空间和时间上的复杂动态。我们专注于旱地凋落物分解，但我们讨论的分层、多学科宏观系统方法展现出解决广泛生态系统中其他空间和时间复杂的生物地球化学过程的巨大潜力。