Hind foot length : an indicator for monitoring roe deer populations at a landscape scale
Résumé
Wildlife managers frequently use estimates of population densities to guide ungulate management. Because it is nearly impossible to obtain accurate counts, these estimates are based on indices. Thus, managers continue to seek new index methods that could help them better monitor and manage ungulate populations. In this paper we examine the usefulness of hind foot length as an ecological indicator of density dependence for monitoring roe deer (Capreolus capreolus) populations. We used the hind feet of all roe deer shot over an entire province for 13 years that were collected by wildlife managers from the Tarn Hunter Federation (France) to conduct this research. Information on the sex, date, and shooting locality were recorded by hunters, and animal age was determined by wildlife managers. We divided the province into 3 biogeographical regions and investigated the relationship between hind foot length of roe deer fawns, spring and summer climate (temperature and precipitation), and an index of deer density (number of shot roe deer per square kilometer) by region using linear models. Hind foot length differed between sexes and between regions. In 2 out of 3 regions, we observed a negative relationship between hind foot length and our index of roe deer density. Further, hind foot length was lower when springs (but not summers) were cold or wet. We interpreted these trends in relation to changes in population density and habitat structure. We concluded that hind foot length is a useful indicator for assessing the density-dependent relationship between roe deer populations and their environment and for monitoring population trends.