Researchers Map Fish Species at Risk from Dams

Dams are believed to be one of the biggest threats to freshwater organisms worldwide: They disrupt normal patterns of water and sediment flow, impede migration, and alter the character of spawning and feeding grounds. A shortage of data has until now prevented a thorough global assessment of the threat dams pose to fish species, but a study described in the June issue of BioScience attempts just that.

The report, by Catherine Reidy Liermann of Umeå University, Sweden, and three coauthors, analyzed 397 ecologically distinct freshwater regions around the world and plotted the occurrence of dams greater than 15 meters high. This approach enabled the researchers to assess the amount of obstruction the dams caused. The authors then examined location data for fish species believed to be at risk of extinction because they are restricted to a specific region or because they have to migrate up rivers as part of their life cycle. This allowed the researchers to identify regions where dams pose the biggest risk to fish species. Factoring in where there has been additional habitat alteration—a known risk for many fishes—allowed the authors to further refine their list of the danger zones.

The results pointed to Murray-Darling Province (Australia), Southern Italy, the Lower and Middle Indus Basin, West Korea, the Upper Paraná (southern Brazil), the South Atlantic coast of the United States, and Mobile Bay ecoregions as having notable numbers of fish species at risk and heavy dam obstruction. Other parts of the United States in the 18 ecoregions deemed to present the greatest risks worldwide include the Great Lakes and part of the Gulf of Mexico. Much of the Danube, Iberia, and the Southern Temperate Highveld in South Africa are also on the list. These 18 ecoregions, the authors write, "merit immediate conservation attention." Eels, shads, lampreys, sturgeons, and salmonids stand out as being especially vulnerable.

The authors explain that their findings will help researchers and planners in identifying important regions where conservation is feasible because the watercourses are relatively unobstructed and are home to at-risk species. The results also flag regions where restoration—possibly even including dam removal—is desirable if fishes are to be conserved.

The complete list of peer-reviewed articles in the June 2012 issue of BioScience is as follows. Articles 1,2,4,5, 6, and 7 are now published ahead of print. Article 3 will be published with the June issue's full contents next month.

1. Implications of Dam Obstruction for Global Freshwater Fish Diversity
Catherine Reidy Liermann, Christer Nilsson, James Robertson, and Rebecca Y. Ng

2. The Effects of Forest Fuel-Reduction Treatments in the United States
Scott L. Stephens, James D. McIver, Ralph E. J. Boerner, Christopher J. Fettig, Joseph B. Fontaine, Bruce R. Hartsough, Patricia Kennedy, and Dylan W. Schwilk

3. Oil Impacts on Coastal Wetlands: Implications for the Mississippi River Delta Ecosystem after the Deepwater Horizon Oil Spill
Irving A. Mendelssohn, Gary L. Andersen, Donald Baltz, Rex Caffey, Kevin R. Carman, John W. Fleeger, Samantha B. Joye, Qianxin Lin, Edward Maltby, Edward Overton, and Lawrence Rozas

4. Legacy Effects in Material Flux: Structural Catchment Changes Predate Long-Term Studies
Daniel J. Bain, Mark B. Green, John L. Campbell, John F. Chamblee, Sayo Chaoka, Jennifer M. Fraterrigo, Sujay S. Kaushal, Sherry L. Martin, Thomas E. Jordan, Anthony J. Parolari, William V. Sobczak, Donald E. Weller, Wilfred M. Wolheim, Emery R. Boose, Jonathan M. Duncan, Gretchen M. Gettel, Brian R. Hall, Praveen Kumar, Jonathan R. Thompson, James M. Vose, Emily M. Elliott, and David S. Leigh

5. Education Improves Plagiarism Detection by Biology Undergraduates
Emily A. Holt

6. Integrating Theoretical Components: A Graphical Model for Graduate Students and Researchers
David M. Choate, Chelse M. Prather, Matt J. Michel, Ashley K. Baldridge, Matthew A. Barnes, David Hoekman, Christopher J. Patrick, Janine Rüegg, and Todd A. Crowl

7. Planetary Opportunities: A Social Contract for Global Change Science to Contribute to a Sustainable Future
Ruth S. DeFries, Erle C. Ellis, F. Stuart Chapin III, Pamela A. Matson, B. L. Turner II, Arun Agrawal, Paul J. Crutzen, Chris Field, Peter Gleick, Peter M. Kareiva, Eric Lambin, Diana Liverman, Elinor Ostrom, Pedro A. Sanchez, and James Syvitski

Researchers call for a new direction in oil spill research

Inadequate knowledge about the effects of deepwater oil well blowouts such as the Deepwater Horizon event of 2010 threatens scientists' ability to help manage and assess comparable events in the future, according to an article that a multi-author group of specialists will publish in the May issue of BioScience. Even federal "rapid response" grants awarded to study the Deepwater Horizon event were far more focused on near-surface effects than on the deepwater processes that the BioScience authors judge to be most in need of more research.

The article, by a team led by Charles H. Peterson of the University of North Carolina, argues that a fundamentally new approach to the study of deepwater oil spills is needed. Previous research has focused mainly on effects on organisms found near the sea surface and on coasts. The new approach would also stress how oil and associated gas released at depth move through the sea and affect subsurface and bottom-dwelling organisms. The new approach is all the more important because the oil industry is now putting most of its exploration efforts into deep water.

Peterson and his colleagues point out that existing policies and legislation have notably failed to provide for research initiated promptly after a spill has been detected. This has prevented studies that might have guided emergency response procedures two years ago, in particular studies of the effects of chemical dispersants. These were used extensively while the Deepwater Horizon spill was in progress, although there is little consensus on their effectiveness.

There remain "serious gaps" in background information needed for longer-term assessments of comparable spills, according to Peterson and his coauthors. Much more information is needed about deep-sea ecology and the processes by which oil released at depth is degraded by microbes, for example. The gaps impede not only litigation and the improvement of government policy but also any attempts to restore damaged ecosystems.

The complete list of peer-reviewed articles in the May 2012 issue of BioScience is as follows:

A Tale of Two Spills: Novel Science and Policy Implications of an Emerging New Oil Spill Model
Charles H. Peterson, Sean S. Anderson, Gary N. Cherr, Richard F. Ambrose, Shelly Anghera, Steven Bay, Michael Blum, Robert Condon, Thomas A. Dean, Monty Graham, Michael Guzy, Stephanie Hampton, Samantha Joye, John Lambrinos, Bruce Mate, Douglas Meffert, Sean P. Powers, Ponisseril Somasundaran, Robert B. Spies, Caz M. Taylor, Ronald Tjeerdema, and E. Eric Adams

Rethinking the Origin of Chronic Diseases
Mohammadali M. Shoja, R. Shane Tubbs, Alireza Ghaffari, Marios Loukas, and Paul S. Agutter

Prospects for Sustainable Logging in Tropical Forests
Barbara L. Zimmerman and Cyril F. Kormos

Energy and Matter: Differences in Discourse in Physical and Biological Sciences Can Be Confusing for Introductory Biology Students
Laurel M. Hartley, Jennifer Momsen, April Maskiewicz, and Charlene D'Avanzo

Studying Biodiversity: Is a New Paradigm Really Needed?
James D. Nichols, Evan G. Cooch, Jonathan M. Nichols, and John R. Sauer

Finding Common Ground for Biodiversity and Ecosystem Services
Belinda Reyers, Stephen Polasky, Heather Tallis, Harold A. Mooney, and Anne Larigauderie

Why Ecosystem-Based Management May Fail without Changes to Tool Development and Financing
Corrie Curtice, Daniel C. Dunn, Jason J. Roberts, Sarah D. Carr, and Patrick N. Halpin

BioScience Press Releases

Researchers Map Fish Species at Risk from Dams

Researchers call for a new direction in oil spill research