Species History Masks the Effects of Human-Induced Range Loss – Unexpected Genetic Diversity in the Endangered Giant Mayfly Palingenia longicauda

Freshwater biodiversity has declined dramatically in Europe in recent decades. Because of massive habitat pollution and morphological degradation of water bodies, many once widespread species persist in small fractions of their original range. These range contractions are generally believed to be accompanied by loss of intraspecific genetic diversity, due to the reduction of effective population sizes and the extinction of regional genetic lineages. We aimed to assess the loss of genetic diversity and its significance for future potential reintroduction of the long-tailed mayfly Palingenia longicauda (Olivier), which experienced approximately 98% range loss during the past century. Analysis of 936 bp of mitochondrial DNA of 245 extant specimens across the current range revealed a surprisingly large number of haplotypes (87), and a high level of haplotype diversity (). In contrast, historic specimens (6) from the lost range (Rhine catchment) were not differentiated from the extant Rába population (, ), despite considerable geographic distance separating the two rivers. These observations can be explained by an overlap of the current with the historic (Pleistocene) refugia of the species. Most likely, the massive recent range loss mainly affected the range which was occupied by rapid post-glacial dispersal. We conclude that massive range losses do not necessarily coincide with genetic impoverishment and that a species' history must be considered when estimating loss of genetic diversity. The assessment of spatial genetic structures and prior phylogeographic information seems essential to conserve once widespread species

Native and alien macroinvertebrate richness in a remnant of the former river Rhine : a source for recolonisation of restored habitats?

Rivers are among the most endangered ecosystems of the world with dramatically decreasing biodiversity. Rehabilitation programmes aiming at restoration of riverine ecosystems rely on the recolonisation of native macroinvertebrates from refuges. We examined whether a relatively natural remnant of the former river Rhine (Altrhein) harbours a higher richness of benthic macroinvertebrates than two sites of the modified Rhine with artificial and semi-natural embankments near Basel. All three sites were bimonthly sampled between May 2007 and May 2008 using three techniques: Kick and Sweep, drifting animals collected from pieces of stone turned by hand, and animals collected from stone surfaces. Taxa richness was higher in the Altrhein than in the two sampling sites in the river Rhine, but it was mainly a result of the large number of individuals sampled at this site. Despite 17% of taxa recorded were alien, the three sampling sites differed neither in the number of alien taxa nor in their abundances. However, lower percentages of both alien taxa and individuals were recorded in the Altrhein than at the other two sites in the Rhine. Indicator value analysis showed that the macroinvertebrate community of the Altrhein maintains several native and specific taxa. Multivariate analyses supported the separation of the communities collected at different sampling sites and also the uniqueness of the community in the Altrhein. The observed patterns, however, strongly depended on the sampling method applied, thereby calling the attention to the application of standard sampling methods and also to the restriction of result comparisons on projects using identical sampling methodology. Our study shows that the remnant of the former river Rhine serves as a refuge for macroinvertebrates which may facilitate future restoration of the river embankment

Native and exotic Amphipoda and other Peracarida in the River Meuse: New assemblages emerge from a fast changing fauna

Samples issued from intensive sampling in the Netherlands (1992-2001) and from extensive sampling carried out in the context of international campaigns (1998, 2000 and 2001) were revisited. Additional samples from artificial substrates (1992-2003) and other techniques (various periods) were analysed. The combined data provide a global and dynamic view on the Peracarida community of the River Meuse, with the focus on the Amphipoda. Among the recent exotic species found, Crangonyx pseudogracilisis regressing, Dikerogammarus haemobaphesis restricted to the Condroz course of the river, Gammarus tigrinusis restricted to the lowlands and seems to regress, Jaera istriis restricted to the 'tidal' Meuse, Chelicorophium curvispinumis still migrating upstream into the Lorraine course without any strong impact on the other amphipod species. After a rapid expansion Dikerogammarus villosushas continued its upstream invasion between 1998 and 2002 at a rate of 30-40 km per year, but no further progression was noticed in 2003. Locally and temporarily the native species (Gammarus fossarum and G. pulex) and naturalized species (G. roeseliand Echinogammarus berilloni)mayhave been excluded by the most recent invaders (mainly D. villosus), but none of the native and naturalized species has disappeared completely. Therefore, the number of amphipod species found in the River Meuse has increased. Moreover, the native and naturalized species keep on dominating the tributaries from which the recent invaders seem to be excluded. A changing Peracarida community structure is observed along the course of the River Meuse: four native or naturalized species inhabit the upstream (Lorraine) course, three invasive species dominate in the middle reach (Ardenne-Condroz zone), one exotic species is housed in the Border Meuse and three or four invasive species dominate the assemblages in the lowlands. © Springer 2005.SCOPUS: re.jinfo:eu-repo/semantics/publishe