Freshwater mussels are among the most rapidly declining components of global biodiversity, but causes of local species disappearances are frequently unknown. We estimated decade-scale local extinction by resampling 118 stream reaches representing the best mussel habitat across a region that was once rich in species and is now mostly converted from prairies and riparian woodlands to intensive agriculture (Iowa, USA). Average species richness was reduced from >5 to <2 species, maximum richness was reduced from 22 to 15 species, and all mussel species were extirpated from 47% of the reaches since 1984 to 1985. More than half of the sites lost >75% of their species. Although 5 of the species were found at 20% to 140% more sites in 1998 than 1984 to 1985, 29 species (83%) decreased an average of 80% in geographic coverage, whereas 8 species were completely lost from these stream sites. Correlation analyses with reach and watershed characteristics determined using GIS and local sampling methods linked the greatest declines to rarity of streamside woodlands, high siltation, and most intensive agricultural land uses, i.e., where conditions had changed most from the historical land cover. The surveys indicated a very large extinction debt has been created by large-scale habitat modification over the last century and ongoing agricultural land uses.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 23 • No. 1