Conservation genetics of the endangered depressed river mussel, Pseudanodonta complanata, using amplified fragment length polymorphism (AFLP) markers

Abstract

ABSTRACT1. Genetic analysis is increasingly recognized as a key tool for understanding demography, and is particularly useful for describing patterns of gene flow between putative populations. Most effort has been directed towards vertebrate systems, where any one study often benefits from marker development in related species. The greater diversity of invertebrate taxa presents a challenge, but amplified fragment length polymorphism (AFLP) markers offer a solution, yielding high levels of polymorphism and no prior knowledge of a species' genome.2. AFLP markers have been used to analyse an unusual metapopulation of an invertebrate, the endangered freshwater mussel, Pseudanodonta complanata, sampled from river systems across the UK. This was done to assess the extent to which individual river systems were genetically isolated from one another.3. The results show patterns of weak genetic differentiation across the UK, with one hydrologically isolated population in the south west showing clear genetic differentiation from the rest of the country. However, the UK population as a whole exhibits significant isolation by distance, particularly when one population subject to fish stocking is removed, this population probably being seeded with mussel glochidia larvae which use fish as vectors. Genetic estimates of inbreeding reveal a complicated pattern in which inbreeding peaks at intermediate densities.High-density populations may be genetically diverse due to their size, while the lowest density populations may represent transient groups of emigrants from other, larger populations.4. The findings show that limited gene flow does exist between some but not all river systems. The isolation of the south-west population indicates that dispersal is variable and should not be assumed to be present. Waterways that remain hydrologically isolated may require special attention in conservation programmes as they can harbour genetically distinct populations. The balance between river management activities and conservation priorities therefore needs careful consideration.

Genetic diversity of the pan‐European freshwater mussel Anodonta anatina (Bivalvia: Unionoida) based on CO1: new phylogenetic insights and implications for conservation

“…Conversely, in populations of Margaritifera margaritifera (Linnaeus, 1758) from several drainages in Spain (Iberia) only two variable sites were found in a 657 bp segment of the COI gene (Machordom et al , ). In addition, the pattern obtained in the present study for A. anatina is very different from the one seen for P. complanata within the UK, where levels of genetic differentiation are modest with surprisingly good gene flow between widely dispersed populations (Skidmore et al, ). Those patterns were explained by human activities such as fish stocking and the interconnectivity of the different drainages.…”

“…While North America is known as a global centre of endemism for freshwater mussels, with over 300 species and subspecies described (Williams et al, 1993;Graf and Cummings, 2007), in Europe the real number of species is still unknown but is considered to be relatively low (about 16). It is interesting to note that the number of phylogeographic and/or genetic diversity studies on European freshwater mussels is surprisingly low (Nagel et al, 1996;Machordom et al, 2003;Araujo et al, 2005Araujo et al, , 2009aGeist et al, 2010;Skidmore et al, 2010), especially when compared with those from North America (King et al, 1999;Serb et al, 2003;Chong et al, 2008;Elderkin et al, 2008;Zanatta and Murphy, 2008;Mock et al, 2010Mock et al, , 2013Zanatta and Harris, 2013;Inoue et al, 2014).Understanding the spatial patterns of unionoid mussel lineages may be especially interesting in southern European peninsulas because these have been shown to have served as refugia during cold periods in the Pleistocene, acting both as centres of origin of endemisms and as sources from which formerly glaciated areas were recolonized during interglacial periods (see Weiss and Ferrand, 2007, for a review). In southern Europe, the main Pleistocene glacial refugia include the Balkans, the Carpathian Mountains, the Italian Peninsula and Iberia (Hewitt, 2000).…”

Conservation status of freshwater mussels in Europe: state of the art and future challenges

“…Because these issues are unresolved we follow traditional usage and recognize Pseudanodonta as containing a single species, P. complanata (e.g. Graf, 2007;Skidmore et al, 2010).…”

Development and multiplexing of microsatellite loci for the near threatened freshwater mussel Potomida littoralis (Cuvier, 1798) using 454 sequencing

“…They are particularly vulnerable to habitat loss and fragmentation, susceptible to flow, pollution and climatic disturbances and introduction of invasive species (Strayer et al, 2004). Moreover, and despite their well-recognized ecological importance, there is a surprising lack of genomic resources currently available for European species (Skidmore et al, 2010). To the best of our knowledge, existing microsatellite primers are only available for two of the native European unionoids A. cygnea (Geist et al, 2010b) and M. margaritifera (Geist et al, 2003).…”