Managed Wolf Populations Could Restore Ecosystems

Researchers writing in the February issue of BioScience propose reintroducing small, managed populations of wolves into national parks and other areas in order to restore damaged ecosystems. The populations would not be self-sustaining, and may consist of a single pack. But the BioScience authors suggest that even managed populations could bring ecological, educational, recreational, scientific, and economic benefits.

The authors, Daniel S. Licht, of the National Park Service, and four coauthors, note that research in recent years has shown the importance of wolves to ecosystems in which they naturally occur. For example, the presence of wolves usually leads to fewer ungulates, which in turn generally means more plant biomass and biodiversity. Wolves can also increase tourism.

Licht and his coauthors believe that wolves introduced for the purpose of ecosystem stewardship, rather than for the creation of self-sustaining wolf populations, could enhance public understanding and appreciation of the animals. Advances in real-time animal tracking made possible through global positioning system technology, as well as the use of contraception and surgery, could help in controlling the growth of introduced populations. This approach might mitigate concerns about depredation of livestock and game, attacks on pets, and human safety, Licht and colleagues maintain. Fences could also play a role.

Wolves were introduced to Coronation Island, Alaska, for ecosystem restoration in 1960, and they successfully controlled deer there before the wolf population grew and subsequently crashed. Licht and his coauthors suggest that with more intensive management this unfavorable outcome could have been avoided, and that desirable results could be expected at many sites in North America and elsewhere, provided there are sufficient prey.

The complete list of peer-reviewed articles in the February 2010 issue of BioScience is as follows:

Metagenomics and the Units of Biological Organization
W. Ford Doolittle and Olga Zhaxybayeva

Ecology and Management of the Spring Snowmelt Recession
Sarah M. Yarnell, Joshua H. Viers, and Jeffrey F. Mount

Prairie Wetland Complexes as Landscape Functional Units in a Changing Climate
W. Carter Johnson, Brett Werner, Glenn R. Guntenspergen, Richard A. Voldseth, Bruce Millett, David E. Naugle, Mirela Tulbure, Rosemary W. H. Carroll, John Tracy, and Craig Olawsky

Still Watching, from the Edge of Extincton
Beverly Peterson Stearns and Stephen C. Stearns

Using Small Populations of Wolves for Ecosystem Restoration and Stewardship
Daniel S. Licht, Joshua J. Millspaugh, Kyran E. Kunkel, Christopher O. Kochanny, and Rolf O. Peterson

Reducing Some Water Flow Rates May Bring Environmental Gains

Conservation projects often attempt to enhance the water-based transport of material, energy, and organisms in natural ecosystems. River restoration, for example, commonly includes boosting maximum flow rates. Yet in some highly disturbed landscapes, restoration of natural water flows may cause more harm than good, according to a study published in the January 2010 issue of BioScience.

The study, by C. Rhett Jackson and Catherine M. Pringle of the University of Georgia, analyzes a wide variety of examples in which creating or maintaining reduced flows can create ecological benefits. The presence of nonnative fishes in a river, for example, can argue for maintaining the isolation of some habitats that are separated from the main channel, because the nonnative species may imperil naturally occurring species. In other cases, novel vegetation that has grown up below a dam may be host to terrestrial animal populations, including endangered birds. Restoring natural water flows can lead to a change in the vegetation that is detrimental to the animals.

Awareness of the potential benefits of maintaining low "hydrologic connectivity" has extended to the creation of artificial barriers to protect species at risk. The endangered native greenback cutthroat trout, for example, is protected from nonnative brook trout moving upstream by the placement of small dams in stream headwaters in the Colorado River basin. Expensive attempts are also being made to deter exotic nuisance species such as bighead carp and silver carp from invading Lake Michigan via the Chicago Sanitary and Ship Canal. Experts disagree on whether the multimillion-dollar electric dispersal barriers now being constructed on the canal will succeed, and some authorities have argued that only permanently disconnecting the canal will protect Lake Michigan.

Many urban streams represent particular challenges when attempts are made to restore natural flows. Expensive restoration efforts in streams in Seattle, for example, led to high pre-spawning mortality of salmon, possibly because they were exposed to copper pollution. Maintaining low flows can also mitigate the effects of pollution on ecosystems when ponds and lakes sequester sediments and nutrients that would otherwise be more widely dispersed. The sediments may contain toxic elements that could cause widespread harm to wildlife.

This insight raises another challenge, however: several National Wildlife Refuges have suffered high mortality of fishes and birds as a result of the concentration of toxic substances in lakes. What is clear is that restoring natural flows can bring pros and cons. Jackson and Pringle conclude that "a major challenge is to develop a more predictive understanding of how hydrologic connectivity operates in intensively developed landscapes."

The complete list of peer-reviewed articles in the January 2010 issue of BioScience is as follows:

The Evolution of Gene Regulatory Interactions
Gregory A. Wray and David A. Garfield

Biodiversity Losses and Ecosystem Function in Freshwaters: Emerging Conclusions and Research Directions
Caryn C. Vaughn

Ecological Benefits of Reduced Hydrologic Connectivity in Intensively Developed Landscapes
C. Rhett Jackson and Catherine M. Pringle

Aerial Photography: A Rapidly Evolving Tool for Ecological Management
Jessica L. Morgan, Sarah E. Gergel, and Nicholas C. Coops

Enhancing the Multifunctionality of US Agriculture
Nicholas Jordan and Keith Douglass Warner

Linking Ecosystem Services, Rehabilitation, and River Hydrogeomorphology
James H. Thorp, Joseph E. Flotemersch, Michael D. Delong, Andrew F. Casper, Martin C. Thoms, Ford Ballantyne, Bradley S. Williams, Brian J. O'Neill, and C. Stephen Haase

BioScience Press Releases

Managed Wolf Populations Could Restore Ecosystems

Reducing Some Water Flow Rates May Bring Environmental Gains