Seasonal variations of Red Deer selectivity on a mixed forest edge.

摘要

Red deer play a major role in shaping forest vegetation, and a better understanding of their selectivity is needed in order to provide a basis for deer habitat and population management. In order to measure deer selectivity, information is required on both the use and availability of different food items at the feeding site scale, which has often been proven difficult to achieve with wild animals. In this study, we introduced three hinds for five days in each season into a 1 ha paddock established on a mixed forest edge. We analysed the relationship between the choices made on the first day in the paddock and the available vegetation, and calculated selectivity indexes (Si). The hinds were highly selective, with on average 82% of their diet made of preferred species. Selected and avoided species varied between seasons according to plant phenology, except for conifers and ferns, which were always avoided. The intermediate feeding style of the Red Deer was confirmed, with concentrate foods (broad-leaved trees and seedlings, shrubs, forbs and legumes) being selected from the spring to the autumn, followed by a switch to grass during the winter. The hinds selected grass in the winter since it was a highly available and relatively "high quality" forage at that time. The net intake of digestible energy was probably increased by eating grass than by searching for the higher quality but scarce forbs. This resulted in the dry matter intake maximization hypothesis being valid during the winter, but rejected for the other seasons. The highly selective consumption of broad-leaved seedlings throughout the growing season suggests a high risk of damage to these seedlings at a year-round deer density of about 15 hinds per km2..