Evolution of population genetic structure of the British roe deer by natural and anthropogenic processes (Capreolus capreolus)

Abstract

Human influence typically impacts on natural populations of conservation interest. These interactions are varied and sometimes complex, and may be negative and unintended or associated with conservation and management strategy. Understanding the details of how these interactions influence and are influenced by natural evolutionary processes is essential to the development of effective conservation strategies. In this study, we investigate a species in Britain that has experienced both negative impact through overhunting in historical times and management efforts through culls and translocations. At the same time, there are regional populations that have been less affected by human influence. We use mtDNA and nuclear microsatellite DNA markers to investigate patterns of connectivity and diversity and find multiple insular populations in Britain that probably evolved within the Holocene (when the habitat was free of ice). We identify three concurrent processes. First, surviving indigenous populations show highly provincial patterns of philopatry, maintaining and generating population structure on a small geographic scale. Second, founder populations into habitat extirpated of native populations have expanded, but remained largely insular. Third, introductions into established populations generate some admixture. We discuss the implications for the evolution of diversity of the integration of natural processes with anthropogenic influences on population size and distribution.

Keywords: Conservation genetics; deer; population bottleneck; population structure; translocation.

Figure 1

Census data mapping presence in 10 km square regions for roe deer across Britain for 1972, 2002, and 2007. Panel to right shows F_ST comparisons from microsatellite DNA data. Census map figure reprinted with permission from British Deer Society report by A. I. Ward.

Figure 2

(a) Median joining network of phylogenetic relationships among modern mitochondrial haplotypes where the size of the circle indicates relative frequency of the haplotype. Haplotypes represented are based on 744 base pairs of the mt-DNA d-loop and exclude singletons. (b) Modern roe haplotypes (excluding singletons) and their distributions across the United Kingdom.

Figure 3

Assignment probabilities of individuals to putative population clusters at (a) K = 4 (b) K = 7 using the program STRUCTURE 2.3.2. Locations where individuals were sampled are indicated below the graph.

Figure 4

Posterior probability of the data (ln [P(D^|K)]) and values of ΔK (Evanno et al. 2005) as a function of K (number of clusters), as resulting from the simulations in structure.

Figure 5

Results of geneland analyses showing posterior probabilities and spatial organizations of roe deer in northern (N1–N7) and southern (S1–S4) regions of mainland Britain.

Figure 6

Posterior proportions of admixture inferred by Geneland for (a) northern and (b) southern populations.

Figure 7

Factorial correspondence analysis (FCA) of population multilocus scores computed using GENETIX. Multilocus scores are computed in the bivariate space defined by the first two factorial components.

Figure 8

Isolation by distance tests for correlation between genetic differentiation (based on microsatellites) and geographic distance between (a) southern roe (R² = 0.40, P > 0.05) and (b) northern roe based on microsatellites (R² = 0.55, P < 0.001).