Population differentiation of zander (Sander lucioperca) across native and newly colonized ranges suggests increasing admixture in the course of an invasion

Abstract

In addition to ecological factors, evolutionary processes can determine the invasion success of a species. In particular, genetic admixture has the potential to induce rapid evolutionary change, which can result from natural or human-assisted secondary contact between differentiated populations. We studied the recent range expansion of zander in Germany focusing on the interplay between invasion and genetic admixture. Historically, the rivers Elbe and Danube harboured the most north-western source populations from which a north-westward range expansion occurred. This was initiated by introducing zander outside its native range into rivers and lakes, and was fostered by migration through artificial canals and stocking from various sources. We analysed zander populations of the native and invaded ranges using nuclear and mitochondrial genetic markers. Three genetic lineages were identified, which were traced to ancestral ranges. Increased genetic diversity and admixture in the invaded region highlighted asymmetric gene flow towards this area. We suppose that the adaptive potential of the invading populations was promoted by genetic admixture, whereas competitive exclusion in the native areas provided a buffer against introgression by novel genotypes. These explanations would be in line with evidence that hybridization can drive evolutionary change under conditions when new niches can be exploited.

Genetic characterization of introduced Tunisian and French populations of pike-perch (Sander lucioperca) by species-specific microsatellites and mitochondrial haplotypes

“…The level of genetic variability of German pikeperch as found in the wild Lake Müggelsee population is comparable to that observed by Khurshut and Kohlmann (2009) (A m = 3.11-3.78 alleles per locus and H e = 0.471) and Eschbach et al (2014) (A m = 5.7 and H e =0.62) in wild populations from Uzbekistan and Germany, respectively, using the same microsatellite loci. Based on microsatellite loci isolated from related species, other studies have examined the genetic variability and structure of wild and introduced pike-perch populations.…”

“…This discrepancy might be due to different source populations originally introduced into France, multiple introductions, founder effects, genetic drift, and natural selection or combinations of any of these factors. A natural contact zone of both lineages exists in Germany and the Czech Republic Eschbach et al 2014).…”

“…In general, the lake populations showed a higher genetic diversity than the coastal ones. Most recently, Eschbach et al (2014) identified three genetic lineages of pike-perch in Germany corresponding to the river basins of the Danube, Oder, and Elbe. They also observed an increased genetic diversity and admixture in invaded regions (either due to stocking or migration through artificial canals) highlighting an asymmetric gene flow towards these areas.…”

Species‐specific preferences of German recreational anglers for freshwater fishing experiences, with emphasis on the intrinsic utilities of fish stocking and wild fishes

“…Although this might be partly explained by the fact that many of the fisheries of the surveyed angling clubs are in fact man‐made (Emmrich et al , ), recent population genetics research on S . lucioperca (Eschbach et al , ) and E . lucius (E. Eschbach, A. Nolte, K. Kohlmann & R. Arlinghaus, unpubl.…”

Spatial variability in the somatic growth of pikeperch Sander lucioperca, an invasive piscivorous fish

“…For example, the slower growth rates that were apparent towards the southerly limits of their range might relate to suboptimal, warm summer temperatures that prevented their efficient growth, and thus depressed the values of K (Lappalainen et al, 2008). There might have also been a genetic component in the spatial growth patterns of S. lucioperca, given that significant population genetic variation has been detected across their range (Eschbach et al, 2014). This could not, however, be tested here.…”