250 



Ac/uafic EiosYslcms — Our Livi/iii Resources 



by 



Arthur E. Bogan 



Freshwater Molliiscaii 



Research 



J. Malcolm Pierson 

 Catera, Alabama 

 Paul Hartfield 



U.S. Fish and Wildlife Service 



Table 1. Summary of the aquatic 

 gastropod fauna of the river sys- 

 tems in the Mobile Bay hasin. 



River, contained six recognized species, all of 

 which are presumed extinct (Table 2; Fig. 3). 



Status and Trends 



Literature records were compiled to docu- 

 ment the gastropod species present historically. 

 Recent surveys of the aquatic gastropod fauna 

 of the Coosa and Cahaba river drainages in 

 Alabama have been conducted by using stan- 

 dard field techniques (Bogan and Pierson 1993 

 a. b). Additional unpublished data (Bogan and 

 Hailfield) are included. 



Recent surveys of the aquatic gastropod 

 fauna at about 800 sites (Table 1) have docu- 

 mented population declines, decreases in 

 species' ranges, and the loss of a major portion 

 of the gastropod diversity, especially in the 

 Coosa River. The Coosa River drainage had at 

 least 82 species historically (Table 1 ); today 26 

 species are presumed extinct in six genera, and 



■ Data from Bogan and Pierson (1993 a,b), Burcti (1989), and A.E. Bogan and P Hartfield (unpublistied data). 



Fig. 1. Live specimens of the endangered tulotoma. 

 TiihiiDiiui imignifica, from Kelly Creek, Elmore County, 

 Alatiama, 1993. 



four genera (Clappia [2 species], Gyrotoma [6 

 species], Amphigyra [I species], and Neo- 

 planorbis [4 species]) are presumed extinct 

 (Tables 1 and 2). The genus Leptoxis has been 

 reduced to a single species restricted to three 

 creek tributary systems in the Coosa River. 



The fauna of the Cahaba River drainage has 

 fared much better (Table 1 ). Although the 

 Cahaba River drainage does not suffer from the 

 numerous dams and the siltation problems of 

 the Coosa River drainage, it is heavily affected 

 by nonpoint-source runoff, siltation, acid mine 

 drainage, pollution from wastewater treatment 



Historical 



Fig. 2. Historical and current dis- 

 tribution of Tulotoma magnifica. 

 Filled circles represent a single or 

 two closely located collection sites 

 (after Hershler et al. 1990). Map 

 modified from the U.S. Geological 

 Survey 1 :500,000 scale— State of 

 Alabama sheet ( 1970 ed.). 



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