Lutra 49(2)_van Wieren et al_2006

Climatic factors affecting a brown hare (Lepus europaeus) population

This study focuses on the possible effects of climatic factors and the frequency of flooding on variation in the size of a population of brown hare (Lepus europaeus) living on a salt marsh on the Wadden Sea island of Schiermonnikoog, the Netherlands. Between 1995 and 2003 an annual count was made each November in a 600 ha study area covering the eastern part of the island. Hare numbers and the change in hare numbers were correlated with a number of parameters, for rainfall, temperature and flooding. The number of hares negatively correlated with total rainfall and the number of months in which rainfall exceeded 100 mm. The change in hare numbers negatively correlated with the same two factors, as well as total rainfall in the reproductive period, the number of months in the reproductive period in which total rainfall exceeded 100 mm, and the number of days in a year that the sea level was > 200 cm above Normal Amsterdam Level. Temperature had no effect. Density independent factors appear to explain a substantial part of the variation found in hare numbers, but it is hypothesized that this variation is superimposed on a hare population that is also, in principle, regulated by density