Clutton-Brock T H, Coulson T N, Milner-Gulland E J, Thomson D, Armstrong H M
Large Animal Research Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
Nature. 2002 Feb 7;415(6872):633-7. doi: 10.1038/415633a.
Populations of red deer that are limited by food, like those of many other ungulates, commonly include more females than males. We assessed the contribution of variation in sex- and age-specific rates of mortality and emigration to density-dependent changes in the adult sex ratio, using long-term observations and demographic experiments involving the red deer population on Rum, Scotland. We incorporated these effects in a stochastic model of local populations under different management regimes to show here that, when female numbers are allowed to increase to more than 60% of the ecological carrying capacity, the sustainable annual harvest of males from local deer populations will fall. Because males are typically culled by fee-paying hunters and generate more income than females, income will decrease as the male harvest falls. Because numbers of female deer throughout much of the Highlands probably exceed the threshold at which male density starts to be affected, many managers might be able to raise income from local deer populations by reducing female numbers, with potential benefits to the vegetation of Scottish Highland environments.
与许多其他有蹄类动物一样，受食物限制的马鹿种群中，雌性通常比雄性多。我们利用长期观测数据以及对苏格兰拉姆岛马鹿种群进行的人口统计学实验，评估了特定性别和年龄的死亡率及迁徙率变化对成年性别比例密度依赖性变化的影响。我们将这些影响纳入不同管理模式下当地种群的随机模型，结果表明，当雌性数量增加到超过生态承载能力的60%时，当地马鹿种群中雄性的可持续年捕获量将会下降。由于雄性通常由付费猎人捕杀，且比雌性创造更多收入，随着雄性捕获量下降，收入也会减少。由于高地大部分地区的雌鹿数量可能超过了开始影响雄性密度的阈值，许多管理者或许能够通过减少雌性数量来提高当地马鹿种群的收入，这对苏格兰高地环境的植被可能有潜在益处。
