Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Removing Dams Can Restore Wildlife Habitat at Small Cost

04.08.2004


By applying new mathematical techniques to river ecology, a University of Maryland biology professor has found that removing dams to reconnect rivers in a watershed like Oregon’s Willamette River could result in significant wildlife habitat restoration benefits at a comparatively small economic cost.



William Fagan, associate professor of biology at the University of Maryland, presented his findings at the Society for Conservation Biology’s Annual meeting, last week at Columbia University.

Fagan’s study looks at the connectivity of an entire watershed, a critical element in the survival of many species of freshwater fish. "Rivers have a unique ecology, because of the branching geometry they exhibit," says Fagan. "My analyses call attention to the importance of connectivity in river systems."


That importance was highlighted in another of Fagan’s recent studies, where he demonstrated that for fishes native to the Sonoran Desert, riverine species with fragmented distributions are more prone to extinction than those with more continuous distributions.

Restoring River Connectivity
While the effects of breaking up wildlife habitat on land with development and other human manipulation have been heavily studied, there has been far less research on what happens to migratory species in freshwater systems when their habitat is fragmented. "Fragmentation has different consequences in freshwater systems than in terrestrial habitats," says Fagan.

For example, migratory fish, such as Pacific salmon in the northwest, need different areas of the river system to complete their life cycles. Pacific salmon spawn upstream in fresh water, but develop in the ocean. Consequently, an individual fish must make two passages through the same riverine system -- one downstream as a juvenile, and one upstream when it’s ready to mate.

"Dams can block or hinder those movements, and consequently there is much discussion about the benefits of reconnecting rivers by removing dams," Fagan says. "However, most of the focus is on removing dams one at a time. My colleagues and I looked at would happen if some dams were removed in a whole watershed and areas of the river habitat were reconnected. We wanted to see what kind of balancing act exists between economic costs of removing dams and the benefits of restoration when the analyses are done at the landscape scale."

Using a system of dams in the Willamette River in Oregon, a habitat for Pacific salmon, as a test case, Fagan and his colleagues explored the economic costs and environmental benefits by applying new math analysis techniques, termed combinatorial multiobjective programming for stream networks, to the question.

"Because of the hierarchical geometry of river systems, you can sometimes get a lot of restoration action with a relatively small economic loss if you consider dam removal systematically at the watershed scale," Fagan says. "Restoration benefits would include increased population sizes of key species of migratory fish, increased dispersal of other species throughout the landscape and return of the natural flow."

Sonoran Desert Fish Show Effects of Fragmentation
In the study that shows the importance connected river habitat for some riverine species, Fagan used mathematical analyses to examine more than 160 years of data on Sonoran Desert fish species in the Colorado River. The goal - to see if patterns of species’ distribution in the past could be a guide as to which species today will be more prone to extinction because of human manipulation of their river habitats.

One such endangered species is the Colorado pikeminnow. A large fish -- an adult ranges between four and six feet in length -- the Colorado pikeminnow must migrate hundreds of kilometers to carry out its life cycle. Damming and diversion of its river habitat and widespread introduction of sport fishes such as bass, which feed on the young pikeminnow, are threatening the native Colorado pike-minnow with extinction.

Using mathematical and statistical techniques to analyze data from thousands of historical records and maps, made as far back as the 1840’s by the U.S.-Mexican Boundary Commission, along with data from the past 20 years, Fagan found that the species most likely to have gone extinct since historic times are those that had more highly fragmented distributions.

"Species that historically have had fragmented distributions have had a tougher time than those that had more cohesive distributions. We show that those species that were historically fragmented have suffered more loss," says Fagan. "That implies that today, those species whose distributions more fragmented because of human activity are more at risk for extinction."

Collaborators on the studies were: Dam Removal - Michael Kuby, Arizona State University; Charles ReVelle, Johns Hopkins University; William Graf, University of South Carolina; Desert Fish, funded by the National Science Foundation - Peter Unmack, Arizona State University; Craig Aumann, Christina Kennedy, University of Maryland.

| newswise
Further information:
http://www.umd.edu

More articles from Ecology, The Environment and Conservation:

nachricht Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>