Drivers of population growth variations for two Mediterranean sympatric Deer

Assessing red deer hunting management in the Iberian Peninsula: the importance of longitudinal studies

Understanding the dynamics of a wildlife population in relation to hunting strategies is essential to achieve sustainable management. We used monitoring data over 25 years from two red deer (Cervus elaphus) populations with different management (with and without supplemental feeding) in South Central Spain to: (i) characterise the density dependence of population dynamics under contrasted management, and (ii) provide the basis for sustainable extraction by considering the theoretical maximum sustainable yield (MSYt) as the reference. The red deer population displayed a typical management reactive culling approach ('saw-tooth-like' curves), with occasional strong annual harvests but not occurring on a regular basis. Interestingly, we found reduced population growth at high densities in both populations, indicating that density-mediated factors determined population growth even when artificial feeding was provided. However, no effects of sex not age class of the extracted population on the population growth rate were determined. The total number of animals hunted was only slightly above those predicted by MSYt (i.e. K _50%) in both populations, despite high densities close to theoretical K, being consistent throughout the study period. The extraction rates (30.3 and 34.0%, for supplemented and unsupplemented populations, respectively) were 13.3% and 10.2% lower compared to the MSYt situation in the unsupplemented and supplemented populations, respectively. Long term population monitoring data provided feasible and suitable baseline values to optimise the sustainable exploitation of red deer populations in the Mediterranean ecosystem under these contrasting management scenarios. Adaptive management, involving objective-driven decision making informed by data on red deer population dynamic, can contribute (i) to maximising the total extraction over the long term while (ii) reducing the ecological impact of high population densities.