Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Prehistoric Decline of Freshwater Mussels Tied to Rise in Maize Cultivation

08.06.2005


USDA Forest Service (FS) research suggests that a decline in the abundance of freshwater mussels about 1000 years ago may have been caused by the large-scale cultivation of maize by Native Americans.

In the April 2005 issue of Conservation Biology, Wendell Haag and Mel Warren, researchers with the FS Southern Research Station (SRS) unit in Oxford , MS, report results from a study of archaeological data from 27 prehistoric sites in the southeastern United States.

Worldwide, freshwater mussels have proven to be highly susceptible to human-caused disturbance, and represent the most endangered group of organisms in North America. Of 297 species found in the United States, 269 freshwater mussel species are found in the Southeast. “We can tie declines of specific mussel populations to the construction of dams, stream channelization, or pollution from a specific source,” says Haag, “but the worldwide patterns of decline in these animals implies that larger-scale disturbances such as sedimentation and nonpoint-source pollution may have an equal impact.”



Among freshwater mussels, members of the genus Epioblasma -- commonly called riffleshells -- are the most endangered. Epioblasma consists of 20 species and eight subspecies; at least 13 of these species and four subspecies are presumed extinct. Of the remaining, the snuffbox mussel ( Epioblasma triquetra ) is the only species not listed on the Federal endangered list. “Human population in the Southeast began to increase steadily about 5000 years ago,” says Warren. “With increasing population came land disturbance from agriculture. This intensified about 1000 years ago, with the beginning of large-scale maize cultivation. No one has really tried to look at how this change in land use impacted water quality and aquatic organisms such as freshwater mussels.”

Working with Evan Peacock from the Cobb Institute of Archaeology at Mississippi State University , Warren and Haag used survey data from prehistoric shell middens -- refuse heaps of shells discarded after eating -- to examine differences in the abundance of Epioblasma species before and after maize cultivation started in the Southeast. They compiled data from both published and unpublished archaeological reports from 27 different sites along 12 rivers in the Southeast. “As far as we can tell, Native Americans harvested mussels without preference for species,” says Haag. “Shell middens provide us with a way to establish the range of freshwater mussel species before human impacts, and to chart changes in relative abundance as impacts increased.”

The researchers found that the relative abundance of riffleshell mussels in the rivers they studied declined gradually during the period between 5000 and 1000 years ago; however, the decline accelerated markedly during the period between 1000 and 500 years ago, when thousands of acres of land were cleared for farming. “We know that freshwater mussels are very sensitive to stream alterations,” says Warren. “Although we cannot entirely rule out the influence of long-term changes in climate, the dramatic changes in land use in this period provide a compelling explanation for the changes in mussel abundance we found.”

Today, none of the riffleshell species the researchers found in ancient middens survive at the study sites, where they were gathered by Native Americans over the millennia before European settlement. Most are extinct as a result of modern land disturbances. “Our results from prehistory support the notion that increases in human activities such as land clearing have measurable effects on freshwater mussel communities,” says Haag, “and that prehistoric human activities put pressures on aquatic ecosystems that were similar to, though certainly less acute than, present-day activities.”

Full text version of the article: www.srs.fs.usda.gov/pubs/9281

For more information:
Wendell Haag at (662-234-2744 x245) or whaag@fs.fed.us
Mel Warren at (662-234-2744 x34) or mwarren01@fs.fed.us

Wendell Haag | EurekAlert!
Further information:
http://www.srs.fs.usda.gov/

More articles from Life Sciences:

nachricht Transport of molecular motors into cilia
28.03.2017 | Aarhus University

nachricht Asian dust providing key nutrients for California's giant sequoias
28.03.2017 | University of California - Riverside

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>