3.6 Freshwater Mussels
Neves et al. 1997; Ganglof et al. 2009) . Te synergistic efects of numerous point and nonpoint source impacts that afect water and habitat quality are likely causes of these declines, with changes to the physical and chemical variables in a stream believed to be principle factors for this decline (Neves et al. 1997; Brim-Box and Williams 2000; Gillies et al. 2003; Lydeard et al. 2004; Ganglof et al. 2009) . 3.6.4 Knowledge Gaps Progress toward species recovery depends on knowledge about species distribution pat- terns as well as a clear understanding of habitat and life history requirements of species (Flebbe and Herrig 2000) . We have limited knowledge and data regarding freshwater mussels compared to other taxa. Accurate distribution information is still lacking for some species, as is work related to fsh host identifcation, ecology (both of individual species and among communities of organisms), and basic systematics (genetics, taxonomy, and morphology). Extensive monitoring of populations is generally lacking. A rigorous phylogenetic study based on quantifable, heritable attributes such as DNA sequence data is needed for scientifcally defensible estimates of North American mussel diversity (Roe and Lydeard 1998) . Such eforts have already yielded surprising departures from traditional classifcations. Molecular studies have uncovered a high degree of cryptic vari- ation not refected by shell morphology. Tese studies show that several currently recog- nized species include multiple evolutionary units (Mulvey et al. 1997; Roe and Lydeard 1998; King et al. 1999; Jones et al. 2006; Serb 2006) , suggesting that diversity of North American mussels has been underestimated. Taxonomic difculties have yet to be resolved for several genera, most notably Elliptio . Tere is an extreme knowledge defcit regarding the pea clams. Attaining information on their distributions should be pursued whenever possible. About 50 species of mussels currently can be found in the wild in North Carolina. Protecting a rich fauna of mussels from environmental contamination requires an under- standing of mussel sensitivity to diverse toxicants. Te vast majority of mussel species remain untested for most toxicants, and estimating safe environmental concentrations is a critical need, especially for the protection of rare, threatened, or endangered species. Freshwater mussel toxicology still lacks full identifcation of pollutants that may limit mussel survival, recruitment, and recovery. Few of the compounds that mussels encounter in the wild have been evaluated in the lab. Also, toxicity tests seldom address mussel repro- duction, and tests are still short relative to mussel lifespans. In particular, there is a need to test previously unevaluated contaminants of emerging concern using long-term exposures that more closely mimic natural conditions, and to evaluate more ecologically relevant endpoints such as mussel health and recruitment.
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2015 NC Wildlife Action Plan
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