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 They compiled data from both published and unpublished archaeological reports from 27 different sites along 12 rivers in the Southeast.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 The birth of a new protein
20.10.2017 | University of Arizona

nachricht Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>