Genetic structuring in the freshwater musselAnodontacorresponds with major hydrologic basins in the western United States

Abstract

Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical subdivision in the most widespread and diverse of these lineages, which includes Anodonta californiensis and Anodonta nuttalliana and occurs from Canada to Mexico. Using mitochondrial and nuclear data, we found that genetic structuring within this clade is inconsistent with morphologically based species designations, but instead follows patterns of vicariance among major hydrogeologic basins. Furthermore, there was a strong tendency for population diversity within drainage systems to increase downstream, implying greater habitat or host fish availability in this direction. Microsatellite results indicated that sampling locations were all genetically distinct, even at short distances. Many of our sample populations showed evidence of a recent demographic bottleneck, although this effect seemed to be very local and not drainage or basin-specific. This study provides a foundation for the establishment of appropriate management units and future research on adaptive differentiation and host fish relationships.

Who lives where? Molecular and morphometric analyses clarify which Unio species (Unionida, Mollusca) inhabit the southwestern Palearctic

“…1 and Table S1 Surprisingly, this rate is much slower than those published for other bivalves (e.g. 0.6 %/my in Renard et al 2000;Mock et al 2010;0.67-1.21 %/my in Marko 2002;and 0.55-2.04 %/my in Luttikhuizen et al 2003). Due to this difference, future studies on Unionida should use the rate obtained in this study instead.…”

Disentangling the divergence and cladogenesis in the freshwater crab species (Potamonautidae:Potamonautes perlatus sensu lato) in the Cape Fold Mountains, South Africa, with the description of two novel cryptic lineages

“…Hydrological networks have been found to be effective barriers to gene flow for many terrestrial and amphibious vertebrates, birds and several freshwater species (Meffe & Vrijenhoek, 1988;Ward, Woodwark & Skibinski, 1994;Avise, Walker & Johns, 1998;Gascon et al, 1998Gascon et al, , 2000Eriksson et al, 2004;Hughes et al, 2004;Domínguez-Domínguez et al, 2006;Hubert & Renno, 2006;Mock et al, 2010;Nicolas et al, 2011). Drainage evolution along the south-eastern and south-western coasts of South Africa, particularly drainage isolation and interconnection, as well as the development of hydrological basins, strongly reflects the history of the transformation of the Cape Fold Mountains (CFM; Waters & Cambray, 1997).…”

The roles of Neogene geology and late Pleistocene lake levels in shaping the genetic structure of the Lahontan redside shinerRichardsonius egregius(Teleostei: Cyprinidae)

“…Physical processes such as volcanism, block faulting, and glaciations have long shaped and altered drainage patterns in western North America, influencing habitat connectivity and thus the genetic structure of numerous aquatic taxa (Hershler & Sada, 2002;Smith et al, 2002;Hershler, Liu & Sada, 2007;Mock et al, 2010). Isolation following episodes of geological or climatic change has led to genetic divergence among species and genera Liu, Hershler & Clift, 2003;Houston et al, 2010a), although dispersal within and among drainages has also frequently countered the effects of isolation (Kauwe, Evans & Shiozawa, 2004;Liu & Hershler, 2007;Boizard, Magnan & Angers, 2009;Stutz, Shiozawa & Evans, 2010).…”