Long-Term Monitoring of European Brown Hare (Lepus europaeus) Population in the Slovak Danubian Lowland

In many European countries over the last few decades, arable fields dominate agricultural landscapes, leading to very intensive land-use practices. This seems to be the main cause of population declines for numerous farmland species, including the European brown hare (Lepus europaeus Pallas, 1778). The Research Institute for Animal Production (National Agricultural and Food Centre—NPPC, Luzianky, Slovakia) has been engaged in a long monitoring project (a project currently running), collecting certain indicators of brown hare population dynamics during hunting season from 1987 to 2023 in the Slovak Danubian Lowland. In the same macro-area (Čiližská Radvaň and Lehnice), a study was conducted on the influence of permanent semi-natural vegetation in relation to recruitment, population density and production. The entire monitored period was aggregated into 5-year intervals (for a total of seven time intervals), with the aim of analyzing the brown hare population dynamics. Spring hare density in the Danubian Lowland is currently 20.8 hares/km2, with harvests of 4.6 hares/km2. During the monitoring period, bag animals have been examined following the regular hunting operations for the purpose of age determination (weight of eye lenses), sex ratio and productivity. There was a large positive effect of set-aside with special mixtures created for hares in large-scale farmed agrarian landscapes on brown hare density, bag and recruitment. In-model hunting grounds with such set-asides increased the spring stock by 25%, bag by 100% and recruitment by 20%. This study reveals that the management of European brown hare is not sustainable in the Slovak Danubian Lowland, and the population is decreasing. This is proven through the decline in harvest brown hares and by population dynamic parameters. Our data suggest that improvements in the habitat quality of arable landscapes by the adoption of permanent semi-natural vegetation may be more effective in the increase in the brown hare population.