Navigation Links
Shifting baselines confound river restoration

Steep reductions in the abundance of fish, shellfish, and other aquatic fauna in recent centuries are not restricted to animals that live in the sea: historical records show that species in rivers and lakes worldwide also experienced sharp declines. Yet the significance of these declines in freshwater species is frequently overlooked by natural resource managers, according to an article in the September 2009 issue of BioScience.

Authors Paul Humphries and Kirk Winemiller argue that as a result of this neglect of historical records, watershed planning is often built on estimates of baseline abundances of fish, freshwater mussels, and beavers that are much lower than actual past abundances. Planners consequently underestimate the likely far-reaching effects such animals had on their ecosystems before European colonization.

Although precise historical numbers cannot be known, written accounts dating from the 1600s suggest that abundances were much greater than they are today. Travelers and diarists reported rivers so full of fish that a spear thrown into the water only rarely missed one, salmon runs that spanned the whole width of a river, and fish so plentiful that they were used as pig feed.

Humphries and Winemiller point out that European colonizers in North America and Australia, in particular, could easily move inland from coastal communities to supplement their seafood with food taken from freshwaters. Then, within a few decades, they started constructing weirs and mills that impeded the migration of fishes and put further pressure on stocks. Stocks of fish and shellfish declined rapidly after colonization. The effects of this early loss of wildlife on the river ecosystems, the authors contend, has not been adequately considered.

Freshwater systems that have been little exploited seem to confirm the strong effects of fishing pressure in freshwater systems. Humphries and Winemiller cite the case of rivers in the Lake Eyre Basin, in central Australia, where fish are much more abundant than in comparable systems that are more heavily exploited.

Humphries, of Charles Sturt University in New South Wales, Australia, and Winemiller, of Texas A&M University in College Station, support the reintroduction of top predators and keystone species recently extirpated from freshwaters, and urge the creation of freshwater protected areas. Some of these protected areas could be used for restoration experiments in which the effects of reintroduced species could be explored.


Contact: Jennifer Williams
202-628-1500 x209
American Institute of Biological Sciences

Related biology news :

1. Shifting Sands highlights past, present and future of Maryland coastal bays ecosystem
2. Sand dollar larvae use cloning to make change, confound predators
3. Genome of simplest animal reveals ancient lineage, confounding array of complex capabilities
4. Baiji Dolphin previously thought extinct spotted in the Yangtze River
5. UC Riverside biologist receives prestigious MacArthur Fellowship
6. International team of scientists warns of climate changes impact on global river flow
7. Stronger EPA leadership needed to improve water quality in Mississippi River
8. UC-Riverside partners with Chinese university to address Chinas environmental problems
9. X-effect: female chromosome confirmed a prime driver of speciation
10. Tiny fish can yield big clues to Delaware River health
11. Scientists from the UGR prove that rivers do not act as barriers for groundwater flow
Post Your Comments:
(Date:11/12/2015)... 2015  Arxspan has entered into an agreement ... for use of its ArxLab cloud-based suite of ... partnership will support the institute,s efforts to electronically ... information internally and with external collaborators. The ArxLab ... the Institute,s electronic laboratory notebook, compound and assay ...
(Date:11/11/2015)... --  MedNet Solutions , an innovative SaaS-based eClinical technology company ... to announce that it will be a Sponsor of the ... be held November 17-19 in Hamburg , ... iMedNet , MedNet,s easy-to-use, proven and affordable ... been able to deliver time and cost savings of up ...
(Date:11/10/2015)... 2015 About signature verification ... to identify and verify the identity of an ... the secure and accurate method of authentication and ... individual because each individual,s signature is highly unique. ... dynamic signature of an individual is compared and ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... 2015 The Global Genomics ... professional and in-depth study on the current state ... ) , The report ... definitions, classifications, applications and industry chain structure. The ... markets including development trends, competitive landscape analysis, and ...
(Date:11/24/2015)... ... November 24, 2015 , ... The United States Golf ... the 2016 USGA Green Section Award. Presented annually since 1961, the USGA Green Section ... her work with turfgrass. , Clarke, of Iselin, N.J., is an extension ...
(Date:11/24/2015)... , Nov. 24, 2015 /CNW/ - iCo Therapeutics ("iCo" ... reported financial results for the quarter ended September ... in Canadian dollars and presented under International Financial ... States ," said Andrew Rae , ... regarding iCo-008 are not only value enriching for ...
(Date:11/24/2015)... /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS) (TSX: AEZ) (the ... the Toronto Stock Exchange, confirms that as of the ... developments that would cause the recent movements in the ... --> About Aeterna Zentaris Inc. ... Aeterna Zentaris is a specialty biopharmaceutical company engaged in ...
Breaking Biology Technology: