Diversity, abundance, and size structure of bivalve assemblages in the Sipsey River, Alabama

Abstract

ABSTRACT1. Patterns of mussel diversity and assemblage structure in the Sipsey River, Alabama, are described. Qualitative data were used to describe river-wide patterns of diversity. Quantitative data were used to describe the structure of mussel assemblages at several sites based on whole-substrate sampling that ensured all size classes were detected.2. Major human impacts to the stream are limited to apparent effects of coal mining in the headwaters and the impoundment of the lower 9 km of the river by a dam on the Tombigbee River. These impacts resulted in a sharp decline in mussel diversity in the headwaters, and extirpation or decline of populations of several large-river species in the lower river that were probably dependent on colonization from the Tombigbee River.3. Despite localized impacts, mussel assemblages throughout much of the river appear to be mostly intact and self-sustaining. These assemblages have several attributes that differ substantially from those in more degraded streams: (1) high retention of historical species richness; (2) gradual, longitudinal increase in species richness from upstream to downstream, resulting in distinctive headwater and downstream assemblages; (3) ubiquity of most species within particular river segments; (4) low dominance and high evenness with large populations of many species; and (5) frequent recruitment for most species resulting in occurrence of individuals in many size classes.4. Few detailed and demographically unbiased descriptions of relatively intact mussel assemblages exist. We propose that characteristics described in the Sipsey River can be used as a baseline comparison for assessing relative degree of assemblage alteration in other streams and can serve as goals for restoration efforts. Published in

Early life history and spatiotemporal changes in distribution of the rediscovered Suwannee moccasinshell Medionidus walkeri (Bivalvia: Unionidae)

“…Our findings show the distribution of Medionidus walkeri has changed during the past century, with an overall reduction in range and fewer individuals found during recent surveys, displaying a common pattern observed for freshwater mussels across river systems worldwide (Cosgrove et al 2000, Geist & Kuehn 2005, Haag & Warren 2010, Hinck et al 2012, Jones et al 2014, Lopes-Lima et al 2016, Zipper et al 2016. The observed spatiotemporal changes in distribution appear confined to the periphery of the species' range in the lower Withlacoochee, lower Su wannee, and upper Santa Fe subbasins (Fig.…”

Long‐term decline of native freshwater mussel assemblages in a federally protected river

“…Changes in mussel assemblages along the length of a river have been found in a number of systems. For example, Haag and Warren (), studying the Sipsey River in Alabama, a large stream that retains much of its original mussel assemblage and ecological function, found self‐sustaining mussel assemblages displaying a gradual increase in species richness from upstream to downstream. The river had different headwater and downstream assemblages, low dominance and high evenness and frequent recruitment for all species resulting in a wide range of sizes of individuals.…”

Fauna and standing crop of freshwater mussels in Poyang Lake, China

“…The loss of freshwater mussels from lakes and rivers would cause a series of ecological problems (Naeem, 1998). Therefore, understanding the natural structure of mussel assemblages is important from both ecological and conservation perspectives (Haag and Warren, 2010).…”