Estimating Sustainable Harvest Rates for European Hare (<i>Lepus Europaeus</i>) Populations

Hunting quotas are used to manage populations of game species in order to ensure sustainable exploitation. However, unpredictable climatic events may interact with hunting. We established a population model for European hares (Lepus europaeus) in Lower Austria. We compared the sustainability of voluntary quotas used by hunters&#8212;which are derived from hare-specific guidelines&#8212;with the actual numbers of hares shot and our recommended quotas for hares, which have been derived from climate and population modeling. We used population modeling based on vital rates and densities to adjust our recommended quotas in order to achieve sustainable harvest. The survival of age classes 1 and 3 had the highest impact on the population growth rate. Population viability analysis showed that a recommended quota with a harvest rate of 10% was sustainable for population densities of 45 hares/km2, and that the threshold for hunting should be raised from 10 hares/km2 so that hare populations with &lt;15 hares/km2 are not hunted. The recommended quota outperformed the voluntary hunting quota, since more hares could be harvested sustainably. Age Class 1 survival was strongly linked with weather: a single year with unfavorable weather conditions (low precipitation) negatively affected population densities. Game species, including the European hare, face increasingly frequent weather extremes due to climate change, so hunting quotas need to be sensitive to frequent population fluctuations

The European Hare (Lepus europaeus): A Picky Herbivore Searching for Plant Parts Rich in Fat.

European hares of both sexes rely on fat reserves, particularly during the reproduc-tive season. Therefore, hares should select dietary plants rich in fat and energy. However, hares also require essential polyunsaturated fatty acids (PUFA) such as linoleic acid (LA) and alpha-linolenic acid (ALA) to reproduce and survive. Although hares are able to absorb PUFA selectively in their gastrointestinal tract, it is unknown whether this mechanism is sufficient to guarantee PUFA supply. Thus, diet selection may involve a trade-off between a preference for energy versus a preference for crucial nutrients, namely PUFA. We compared plant and nutrient availability and use by hares in an arable landscape in Austria over three years. We found that European hares selected their diet for high energy content (crude fat and crude protein), and avoided crude fibre. There was no evidence of a preference for plants rich in LA and ALA. We conclude that fat is the limiting resource for this herbivorous mammal, whereas levels of LA and ALA in forage are sufficiently high to meet daily requirements, especially since their uptake is enhanced by physiological mechanisms. Animals selected several plant taxa all year round, and preferences did not simply correlate with crude fat content. Hence, European hares might not only select for plant taxa rich in fat, but also for high-fat parts of preferred plant taxa. As hares preferred weeds/grasses and various crop types while avoiding cereals, we suggest that promoting heterogeneous habitats with high crop diversity and set-asides may help stop the decline of European hares throughout Europe

Model averaged coefficients for the response variable LA (n = 269).

<p>The intercept stands for the estimate for female adults in summer.</p><p>Model averaged coefficients for the response variable LA (n = 269).</p

Kernel density estimates for dry matter components available and used by European hares.

<p>Kernel density estimates for dry matter (DM) components (a) carbohydrates, (b) crude fat, (c) crude fibre and (d) crude protein [mg/g], available to and used by European hares (n = 263). Used components (in the diet) are indicated in white; available components (in the forage sampled in the habitat) are indicated by grey shading.</p

Chesson’s Electivity Indices for plant taxa.

<p>Chesson’s Electivity Indices in European hares (n = 399) and their distributions of 1000 bootstrap resamples (mean and 95% confidence interval) for plant taxa selected by n≥7 hares (sample size in brackets is the number of hares selecting each plant taxon). Non-significant results cross the vertical line at zero. See text for details of statistics.</p

Post-hoc test results of the electivity indices (parameter estimates β and <i>p</i>-values) of the different fatty acids for the covariate season using the Tukey’s all-pair comparisons method (n = 269).

<p>Post-hoc test results of the electivity indices (parameter estimates β and <i>p</i>-values) of the different fatty acids for the covariate season using the Tukey’s all-pair comparisons method (n = 269).</p

Post-hoc test results of the electivity indices (parameter estimates β and <i>p</i>-values) of all DM components for the covariate season using the Tukey’s all-pair comparisons method (n = 263).

<p>Post-hoc test results of the electivity indices (parameter estimates β and <i>p</i>-values) of all DM components for the covariate season using the Tukey’s all-pair comparisons method (n = 263).</p

Plant taxa included in the five plant groups: cereals, intertillage, other field crops, trees/shrubs, weeds/grasses.

<p>Asterisks indicate plant species occurring in the plant groups weeds/grasses or other field crops and intertillage.</p><p>Plant taxa included in the five plant groups: cereals, intertillage, other field crops, trees/shrubs, weeds/grasses.</p