Data from: Response of moose hunters to predation following wolf return in Sweden

Background: Predation and hunter harvest constitute the main mortality factors affecting the size and dynamics of many exploited populations. The re-colonization by wolves (Canis lupus) of the Scandinavian Peninsula may therefore substantially reduce hunter harvest of moose (Alces alces), the main prey of wolves. Methodology/Principal findings: We examined possible effects of wolf presence on hunter harvest in areas where we had data before and after wolf establishment (n = 25), and in additional areas that had been continuously exposed to wolf predation during at least ten years (n = 43). There was a general reduction in the total number of moose harvested (n = 31,827) during the ten year study period in all areas irrespective of presence of wolves or not. However, the reduction in hunter harvest was stronger within wolf territories compared to control areas without wolves. The reduction in harvest was larger in small (500-800 km2) compared to large (1,200-1,800 km2) wolf territories. In areas with newly established wolf territories moose management appeared to be adaptive with regard to both managers (hunting quotas) and to hunters (actual harvest). In these areas an instant reduction in moose harvest over-compensated the estimated number of moose killed annually by wolves and the composition of the hunted animals changed towards a lower proportion of adult females. Conclusions/Significance: We show that the re-colonization of wolves may result in an almost instant functional response by another large predator—humans—that reduced the potential for a direct numerical effect on the density of wolves’ main prey, the moose. Because most of the worlds’ habitat that will be available for future colonization by large predators are likely to be strongly influenced by humans, human behavioural responses may constitute a key trait that govern the impact of large predators on their prey.

一、研究背景
捕食行为与狩猎收获是诸多受开发利用种群的种群规模与动态变化的主要死亡驱动因素。因此，灰狼（Canis lupus）重新定居至斯堪的纳维亚半岛，或可大幅降低作为其主要猎物的驼鹿（Alces alces）的狩猎收获量。

二、研究方法与主要发现
我们针对两类区域分析了灰狼存在对驼鹿狩猎收获的潜在影响：一类是拥有灰狼定居前后观测数据的区域（样本量n=25），另一类是至少连续十年持续遭受灰狼捕食的区域（样本量n=43）。在为期十年的研究周期内，所有区域的总狩猎驼鹿量（共计31827头）均出现普遍下降，无论该区域是否有灰狼分布。但相较于无灰狼分布的对照区域，灰狼领地内的狩猎收获量下降幅度更为显著。相较于面积为1200~1800 km²的大型灰狼领地，面积为500~800 km²的小型灰狼领地内的狩猎收获量下降幅度更大。在新近有灰狼定居的区域，驼鹿管理策略似乎同时适配管理者（狩猎配额制定）与狩猎者（实际狩猎行为）。此类区域的驼鹿狩猎量出现即时下降，其降幅超出了灰狼每年预估的捕杀量；同时，狩猎个体的组成结构发生变化，成年雌性个体的占比有所降低。

三、研究结论与意义
本研究表明，灰狼的重新定居可能会触发另一大型捕食者——人类——的近乎即时的功能响应，该响应削弱了灰狼对其主要猎物驼鹿种群密度产生直接数量效应的潜力。由于未来可供大型捕食者定居的全球多数栖息地均会受到人类活动的强烈影响，人类的行为响应或可成为调控大型捕食者对其猎物产生影响的关键因素。