単純な農業景観におけるヨーロッパハタネズミの生息密度および出現に対する地域および景観スケールの影響

Agricultural intensification causes significant species loss in agricultural landscapes. One species particularly affected is the critically endangered common hamster (Cricetus cricetus). To counteract hamster decline, it is essential to analyze scale-dependent factors that determine hamster occurrence and densities, especially in structurally simple landscapes. We mapped hamster burrows in the predominantly simple agricultural landscapes of Saxony-Anhalt, Central Germany. At the local scale, we studied the effects of the hamster protection measure of high cut harvest and common vole abundance as well as satellite-based vegetation indices. At the landscape scale, we studied the effects of landscape composition (percentage of winter cereals, oil seeds, uncultivated land, crop diversity) and configuration (edge density, mean field size, distance to the nearest forest, and urban fabric). Our results showed that hamster densities and vole abundance were negatively associated, whereas high cut harvest had a non-significant but slightly positive effect on hamster densities. Satellite-based vegetation indices showed no effect on hamster occurrence. At the landscape scale, the percentage of winter cereals around study field centers increased the probability of hamster occurrence, while further landscape indices had no effect, likely due to the already too simply structured landscape. Our study shows that at the local scale, attention should be paid to adapted vole pest management in order to ensure that hamsters are not further harmed. Whereas, high cut harvest as a single measure is not sufficient to stabilize hamster populations at the local scale, at the landscape scale other factors such as agri-environmental schemes should be considered in simple landscapes to prevent the steady population decline.