Red deer (Cervus elaphus) spatial use in the Italian Alps: home range patterns, seasonal migrations, and effects of snow and winter feeding

Abstract

The spatial behaviour of 20 red deer was analyzed for the first time in the Italian Alps using radio-telemetry, from 1995 to 1997 in the Tarvisio forest, and from 1995 to 1999 in the Susa valley. Two distinct strategies of spatial behaviour were displayed in both study areas, i.e., migratory and stationary. Migratory red deer showed significantly larger annual home ranges, as each year they reached distant summer areas located at higher altitudes. Stationary red deer, instead, remained in the same areas throughout the year, with the exception of summer movement to neighbouring areas at higher altitude. As a consequence of these movements towards and from summer areas, spring and autumn migratory home ranges were significantly larger, while stationary home ranges recorded during spring, summer, and autumn were comparable in size. In winter home range sizes were limited in all monitored deer whenever snow cover reduced their mobility. Migratory red deer movements proved to be markedly affected by snowfall, with their monthly altitudes inversely correlated with snow presence on the ground. Stationary deer vertical movements proved less affected by presence of snow, as they reached lower altitude during summer. During winter, migratory red deer showed a greater use of the Tarvisio supplementary feeding stations, the only study site where this practice was in use. Migratory individuals probably adopted an opportunistic strategy, using the Alpine meadows at higher altitudes during the summer and the feeding stations during the winter, even if the use of feeding stations may be the end result of a poorer knowledge of trophic availability inside the winter areas. During the winter all the monitored deer used the same areas; food supply should be avoided in order not to promote high deer concentration and to reduce the risk of heavy forest browsing.