Navigation Links
Shifting baselines confound river restoration
Date:8/31/2009

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
jwilliams@aibs.org
202-628-1500 x209
American Institute of Biological Sciences
Source:Eurekalert

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:
*Name:
*Comment:
*Email:
(Date:2/21/2017)... and PORTLAND, Ore. , ... and the Avamere Family of Companies (Avamere Health Services, ... announced a six-month research study that will apply the ... eldercare at senior living and health centers. By analyzing ... hopes to gain insights into physical and environmental conditions, ...
(Date:2/14/2017)... N.C. , Feb. 14, 2017  Wake Forest ... M.D., as its new chief executive officer (CEO). Freischlag ... CEO John D. McConnell , M.D., who last ... position at the Medical Center, after leading it since ... the full scope of Wake Forest Baptist,s academic health ...
(Date:2/10/2017)... -- Research and Markets has announced the ... Scientific and Commercial Aspects" to their offering. ... Biomarkers play ... therapy for selection of treatment as well for monitoring the ... disease in modern medicine. Biochip/microarray technologies and next generation sequencing ...
Breaking Biology News(10 mins):
(Date:3/24/2017)... Mar. 24, 2017 Research and Markets has ... Research - Global Strategic Business Report" report to their offering. ... This report ... in US$ Million. Annual estimates and forecasts are provided for the ... primary and secondary research. The report profiles 25 ...
(Date:3/24/2017)... , March 24, 2017 ... the trading session at 5,817.69, down 0.07%; the Dow ... 20,656.58; and the S&P 500 closed at 2,345.96, marginally ... 4 sectors closed in green, 4 sectors finished in ... This Friday, Stock-Callers.com has initiated reports coverage on the ...
(Date:3/24/2017)... , March 24, 2017 Agenus Inc. (NASDAQ: ... checkpoint antibodies and cancer vaccines, today announced participation at ... th  Annual William Blair and Maidstone Life Sciences conference ... Center in New York, NY . ... March 29 at 9:40 am: Robert B. Stein ...
(Date:3/23/2017)... ... 2017 , ... Lajollacooks4u is proud to announce it has become the premiere team-building cooking event ... companies around the world, such as Illumina, HP and Qualcomm, and is ranked #1 in ... popularity is due to its new team building format, a way for teams to not ...
Breaking Biology Technology: