Statewide Assessment of Freshwater Mussels (Bivalvia: Unionidae) in Iowa Streams
Statewide Assessment of Freshwater Mussels (Bivalvia: Unionidae) in Iowa Streams

Author: Kelly Elizabeth Arbuckle

Publisher:

Published: 2000

Total Pages: 228

ISBN-13:

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This study examined freshwater mussel communities, population densities and recent impacts in Iowa, USA. Data collected from streams previously surveyed (1984-85) and from field surveys in this study (1998-99) were used to examine presence, absence, abundance and recent changes in presence/absence of mussel species at different spatial scales. Results indicate an association between mussel impacts and agricultural land use in separate analyses examining habitat characteristics at different spatial scales. Analysis of mussel species richness at 118 sites showed sharp declines in species richness over the past decade. Species richness declined most dramatically at sites having 50% riparian woodland along the stream length surveyed. At the watershed scale, species richness declined in watersheds where agricultural land use accounted for 25% of the total land area. Over 38 watersheds, we found that watershed mean mussel density and species richness were best correlated with average watershed slope (topographic relief) and presence of alluvial deposits. An analysis of the influence of riparian and instream characteristics on mussel species richness and population density at 200 sites surveyed in 1998-99 showed that stream shading (an effect of riparian woodland) had a significant positive effect on mussel density and mussel species richness. Mussel species richness was negatively correlated with agricultural nutrients, total nitrogen (TN) and total phosphorus (TP). The influence of landscape features on mussel communities is clear in each analysis: degradation of lands adjacent to freshwater ecosystems adversely impacts mussel habitat and the associated mussel communities. These results have important implications in the context of restoration and conservation efforts.

The Freshwater Mussels (Bivalvia: Unionidae) of the Harpeth River Drainage and the Upper and Middle Duck River Tributaries, Tennessee
The Freshwater Mussels (Bivalvia: Unionidae) of the Harpeth River Drainage and the Upper and Middle Duck River Tributaries, Tennessee

Author: Kristin Leigh Irwin

Publisher:

Published: 2018

Total Pages: 139

ISBN-13:

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The Cumberland and Tennessee River drainages harbor high diversity and endemism of freshwater mussels. The faunas of the Harpeth River drainage and Duck River tributaries have been disproportionally understudied relative to other Cumberlandian streams. Forty-two sites on 23 tributaries in the Harpeth River drainage and a 21-kilometer reach of the main channel were assessed qualitatively for freshwater mussels. Relic shells of four species were observed in eight sites on four of the tributaries. Twenty species were observed in the main channel including the discovery of a new Harpeth River drainage record: Simsponaias ambigua. Catch per unit effort (CPUE) ranged from 0.0 to 32.0 mussels/h. Lampsilis fasciola and Potamilus alatus were the most abundant species. Mussel populations were fragmented and all species exhibited primarily large size-classes. Eighty-three sites on 37 tributaries in the upper and middle Duck River drainage were sampled qualitatively. Nineteen species were observed and 12 were collected live or fresh dead, and CPUE ranged from 0.0 to 58.0 mussels/h. Villosa vanuxemensis and Villosa taeniata were the most abundant and widespread species observed. Live mussels were found in only five tributaries, although mussels historically occurred in 17 of the sampled streams. Length frequency analysis indicated recent recruitment for four species in Big Rock Creek. Results of canonical correspondence analysis for both drainages revealed no association between environmental variables and mussel community structure (live and fresh dead individuals combined), likely a result of low densities. Two sites on Big Rock Creek in the Duck River drainage were sampled quantitatively using 0.25-m2 quadrats. Densities were 0.33 and 1.27 mussels/0.25m2 and species richness ranged from four to five. Quantitative sampling indicated that qualitative timed searches may be sufficient for detecting recruitment in small streams. Anthropogenic alteration has resulted in extensive loss of freshwater mussel habitat, leading to local extirpations and a reduction of diversity and abundance in both watersheds.

An Analysis of Freshwater Mussels (Unionidae) in the Quiver River and Bogue Phalia, Mississippi, 1994-95
An Analysis of Freshwater Mussels (Unionidae) in the Quiver River and Bogue Phalia, Mississippi, 1994-95

Author: Andrew C. Miller

Publisher:

Published: 1997

Total Pages: 56

ISBN-13:

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A survey to assess community characteristics, density, population demography of dominant species, and the presence of rare or endangered species of mussels (Family: Unionidae) was conducted in selected reaches of the Quiver River and Bogue Phalia, Mississippi, in 1994 and 1995 for the U.S. Army Engineer District, Vicksburg. Results are being used to assess the economic value of mussels in the project area and to determine the environmental effects of proposed maintenance dredging. The project area included a section of the Quiver River between its confluence with the Big Sunflower River immediately north of Highway 82 in Sunflower County to the Leflore-Tallahatchie county line. In the Bogue Phalia, the study area consisted of a reach between Highway 82 and Rosedale, west-central Bolivar County. Twenty-two species of native freshwater mussels were collected in the Quiver River; 26 sites were sampled using qualitative methods, and a total of 2,238 mussels were collected. The dominant mussel was Amblema p. plicata, which comprised over 67 percent of the mussel fauna. Plectomerus dombeyanus comprised 20 percent of the mussels. Overall species diversity (0.67 to 0.90) was low, mainly because of the dominance of A. p. plicata. Evidence of recent recruitment was low; approximately 7 percent of the species and 0.15 percent of the individuals collected were less than 30 mm total shell length. Overall mean density ranged from less than 8.6 individuals/square meter at River Mile (RM) 6.4 to 92.3 individuals/square meter at RM 19.7.