Rappel sur séminaire ECCOREV-IRSTEA 24 septembre

Titre : Ecology and conservation of freshwater mussels in North America
Wendell R. Haag, Fisheries Research Biologist
USDA Forest Service Southern Research Station, Oxford, MS, USA
http://www.srs.fs.usda.gov/staff/260

North America supports the most diverse freshwater mussel fauna on Earth (about 300 species). The group also encompasses a diversity of life history strategies ranging from short-lived species that readily colonize disturbed habitats to long-lived species that are dependent on stable habitats. As filter feeders, these animals are important in aquatic food webs, but they are highly imperiled and about half the fauna is in danger of extinction. An initial extinction wave occurred in the mid-20th century after widespread destruction of riverine habitat by dams. This extinction wave primarily affected species within a single life history strategy that did not adapt to impoundment. A second extinction wave is now underway, but the causes of these extinctions are poorly understood. Unlike the first extinction wave, imperiled species are made up of a representative cross-section of mussel diversity encompassing all life history strategies and taxonomic groups. Our research group is attempting to identify specific causes of mussel declines. I will discuss the results of several large scale experiments focused on factors affecting different parts of the mussel life cycle and an upcoming experiment to assess the effects of pesticides, ammonia, and other contaminants on juvenile mussel survival.