Habitat quality influences relative antler size and hunters’ selectivity in roe deer

Abstract

Understanding factors affecting antler size, and the extent to which harvesting is selective for these traits, is important in order to address management strategies aimed to minimize the risk of negative evolutionary consequences. In an Alpine study area, we compared the phenotypic quality and the antler size of 2,725 male roe deer hunted in two regions differing for winter harshness and habitat quality, and evaluated whether the selective behaviour of recreational hunters was influenced by phenotypic quality and antler size. Antler length and antler circumference relative to both body mass and jaw length were larger in the region with more favourable climate and habitat conditions, indicating that here roe deer were able to allocate more resources to antler growth. The analysis of the temporal trends of harvest bags suggested that hunters did not select roe deer for their body mass or size, but instead for antler size. This resulted also in a preference for sub-adult and adult age classes, while yearlings were culled reluctantly, especially in the region where antlers were smaller. Our results indicate that environmental heterogeneity may influence the relative investment in antler growth. In this way, it may interact with the hunters’ preferences increasing the risk that recreational hunting of roe deer, which is a widespread practice in many European countries, might result in alteration of male age structure and possibly in directional artificial selection.