Genetic consequences of human management in an introduced island population of red deer (Cervus elaphus)

Abstract

We investigated phylogeography and spatial genetic structure in an introduced island population of red deer (Cervus elaphus) on the Isle of Rum, Scotland, experiencing spatial variation in management regime. Five different mitochondrial DNA (mtDNA) haplotypes were present among female red deer on Rum. These comprised two phylogenetically divergent groups, one of which clustered with red deer from Sardinia and North Africa, while the other four grouped with other Western European red deer. Recent and historical red deer management practices explain this result. The Rum population is descended from recent introductions from at least four different UK mainland populations, and translocation of red deer within the UK and across Europe is well documented. We found significant spatial genetic structure across Rum in both mtDNA haplotypes and microsatellite markers. Mitochondrial spatial structure was over an order of magnitude greater than structure in nuclear markers. This extreme difference is explained by the fact that the Rum population was introduced from different source populations, the highly male-biased dispersal patterns of red deer and the much smaller effective population size of mitochondrial compared to nuclear markers. Spatial structure in mtDNA conformed to a pattern of isolation by distance, while nuclear DNA did not. Apparent structure in the nuclear markers was driven by differences between the North Block and the rest of the island. We suggest that recent differences in the management regimes in different parts of the island have led to differences in effective male migration that would account for this observation.