Living in Heterogeneous Woodlands – Are Habitat Continuity or Quality Drivers of Genetic Variability in a Flightless Ground Beetle?

Abstract

Although genetic diversity is one of the key components of biodiversity, its drivers are still not fully understood. While it is known that genetic diversity is affected both by environmental parameters as well as habitat history, these factors are not often tested together. Therefore, we analyzed 14 microsatellite loci in Abax parallelepipedus, a flightless, forest dwelling ground beetle, from 88 plots in two study regions in Germany. We modeled the effects of historical and environmental variables on allelic richness, and found for one of the regions, the Schorfheide-Chorin, a significant effect of the depth of the litter layer, which is a main component of habitat quality, and of the sampling effort, which serves as an inverse proxy for local population size. For the other region, the Schwäbische Alb, none of the potential drivers showed a significant effect on allelic richness. We conclude that the genetic diversity in our study species is being driven by current local population sizes via environmental variables and not by historical processes in the studied regions. This is also supported by lack of genetic differentiation between local populations sampled from ancient and from recent woodlands. We suggest that the potential effects of former fragmentation and recolonization processes have been mitigated by the large and stable local populations of Abax parallelepipedus in combination with the proximity of the ancient and recent woodlands in the studied landscapes.

Functional traits drive ground beetle community structures in Central European forests: Implications for conservation

“…Our results suggest that occurrence ranks can be a useful tool to identify rare species. For example, Abax parallelepipedus showed one of the highest occurrence ranks and is known to have stable population dynamics (Chaabane et al 1996;Günther and Assmann 2004) and consequently little genetic differentiation (Marcus et al 2015). In contrast, Carabus irregularis, a species which has high levels of genetic differentiation as a result of small population sizes or low gene flow (Homburg et al 2014a) and is listed as an endangered species in Germany (Schmidt et al 2016), had low occurrence ranks in our study.…”

Ground beetles in city forests: does urbanization predict a personality trait?

“…Furthermore, in only one species the population density was higher in highly urbanized areas and we generally detected no effect of density on behaviour. Other factors, that could explain differences in behaviour of ground beetles between the differently urbanized sites may, for instance, include litter layer depth ( Marcus et al, 2015 ) or food availability. The litter layer is the primary habitat for ground beetles and their prey; and litter decomposition rate increases along urbanization gradients ( Pouyat, McDonnell & Pickett, 1997 ), resulting in reduced litter depth ( Van Nuland & Whitlow, 2014 ).…”

“…Small holes in the bottom of the outer cup served as drain. Both, inner and outer cup of each trap were baited with red wine on a piece of cellulose ( Marcus et al, 2015 ). Pitfall traps were dug in the ground and covered with metal mesh.…”

Threshold and weighted-distance methods: a combined multiscale approach improves explanatory power of forest carabid beetle abundance in agricultural landscape

“…Although A. parallelepipedus shows a preference for forest habitats, we do not know the dispersal pattern of the individuals, we thus used circular vector buffers. Previous studies show that the area prospected by an individual varies according to the habitat, and the dispersal power of individuals was found to be low-on average 1 m per day and about 2 m per day for the most active males (Charrier et al 1997;Marcus et al 2015). The estimated life span is one to two years for large carabid beetles (Coulon et al 2011).…”