Wild animals have always been an important resource for humans, and we are known to utilize a range of species from different taxa. However, this utilization, and in particular human harvesting, is known to have a large impact on natural populations, and may cause undesirable life history changes over shorter periods of time than expected from natural selection. In wild ungulate populations unrestricted trophy hunting is believed to cause strong selection pressures resulting in evolutionary change towards smaller trophies. However, sufficiently strong directional hunter selection must be present to induce long-term decrease in trophy size, and how harvesting selection varies in space and time has rarely been tested. The key to changes in trophy size is hunter selectivity for specific phenotypic traits. We analyze two unique datasets of harvesting records spanning decadal (1973-2008) and century (1881-2008) scales to identify potential phenotypic trait changes during this time and how harvest selection vary in space and time in red deer (Cervus elaphus).
Results/Conclusions
Our results show that patterns of red deer antler size spanning more than a century were remarkably similar both in space and time. We found a common spatial trend with recent antler sizes being as large as or even larger than earlier peaks in the time series. For the decadal scale data, we found selection patterns to be very dynamic for age-specific trophy size in space and time when comparing foreign and local hunters. This provides evidence that harvesting selection is more variable than earlier assumed. This may contribute to the lack of evidence of a long-term negative trend over more than a century of the largest red deer antlers recorded at trophy exhibitions in Hungary, but unexplained recent increases in antler size suggest other management restrictions and/or environmental factors to play a role for antler size development.
This study highlights that trophy hunting is not necessarily an unsustainable practice that lead to a decline in trophy sizes even over century long time scales. Also, we need to identify the conditions enabling sustainable management in the long term. We also discuss a set of factors that could form the basis for a theory of evolutionary enlightened management of trophy hunting, including factors such as spatial and temporal refuges, compensatory culling, saving stags until prime age culmination and higher prices for larger trophies.