Context

Terrestrial landscapes surrounding aquatic habitat influence the persistence of amphibian spatially structured populations (SSPs) via their crucial role in providing estivation and overwintering sites, facilitating or hampering dispersal and colonisation, and consequently the maintenance or loss of genetic diversity.

Objectives

To highlight the landscape drivers of genetic variation, we investigated the relationship between the level of genetic variation measured within ponds of the great crested newt (Triturus cristatus), and the composition of the surrounding landscape at various spatial scales.

Methods

Based on the sampling of 40 ponds in thirteen SSPs, the influence of landscape features on several estimators of genetic variation was investigated via linear mixed models, with effects within and between SSPs incorporated.

Results

The best models depended on the spatial scale, with more significant associations within radii of 50 and 100 m of core ponds, particularly for allelic richness. Responses within and between SSPs were mostly similar. The availability of aquatic habitat in the landscape had a positive effect, while woodland, arable land and pasture had different effects depending on scale and response variable. Total length of roads within a 250 m radius influenced effective population size negatively.

Conclusions

Our results stress the need to investigate the influence of environmental predictors at multiple spatial scales for an adequate understanding of ongoing processes. Generally, the landscape affected genetic variation similarly within and between SSPs. This allowed us to provide general guidelines for the persistence of great crested newt populations, with an emphasis on the importance of the aquatic habitat.

Multilocus genotypes of great crested newts at 31 microsatellite loci were collected via multiplex PCR and genotyping analysis on an ABI 3500 Genetic Analyzer. Allele calls were scored using the GeneMapper v.4.0 and v.4.3 software packages with fragment sizes based on GeneScan 600 LIZ Size Standard. Negative controls were included in each 96‐well PCR to allow for detection of reagent contamination. To test for reproducibility, samples were blindly replicated two to five times within and across well plates, starting from DNA extract. Genotypes of recaptured great crested newts, poor quality genotypes and identified full sibs among larvae within ponds using the software COLONY 2.0.6.5 following a maximum likelihood approach were excluded. Genotypes of 1332 individuals collected in 52 ponds from 13 spatially structured populations remained.

The csv file shows the microsatellite genotypes of great crested newts with in the first eight columns the following information: the sample ID, the ID of the spatially structured population (SSP-ID), the pond ID, the year of sampling, the longitude followed by the latitude of the pond (WGS84), the life stage of the individual and sex (m: male; f: female). Unavailable or unknown information is denoted with “NA” in these columns. The next 31 columns represent the different microsatellite markers with the loci names mentioned in the column headers. Alleles are separated by a forward slash. Missing genotypes are indicated with “0/0”.