Pedersen H C, Steen H, Kastdalen L, Brøseth H, Ims R A, Svendsen W, Yoccoz N G
Norwegian Institute for Nature Research, Tungsletta 2, 7485 Trondheim, Norway.
Proc Biol Sci. 2004 Feb 22;271(1537):381-5. doi: 10.1098/rspb.2003.2599.
Ptarmigan and grouse species (Lagopus spp.) are thought to be able to compensate for a modest harvest because there is a surplus of breeding birds that are prevented from breeding by territory holders. To estimate the degree of harvest-mortality compensation reliably we experimentally harvested 0%, 15% and 30% of the willow ptarmigan (Lagopus lagopus) on 13 estates ranging from 20 to 54 km2 in size during four hunting seasons in Norway according to a regional block design. Population overwinter growth rate was strongly negatively density dependent, but despite this, and contrary to earlier findings, only 33% of the harvest was compensated for. The lack of compensation was probably caused by long-distance juvenile dispersal that was unaffected by the harvest. The need for large-scale management experiments to detect the effects of harvest was clearly demonstrated: lack of compensation was found only when we used the whole dataset and not when the data were analysed by year or block. Our study shows that it is very difficult to demonstrate a population's lack of harvest compensation and warns against using small-scale, out-of-season or poorly replicated studies as a basis for future harvest-management decisions.
雷鸟和松鸡物种（矛隼属）被认为能够补偿适度的捕猎，因为有多余的繁殖鸟类被领地所有者阻止繁殖。为了可靠地估计捕猎死亡率补偿的程度，我们根据区域区组设计，在挪威四个狩猎季节里，在13个面积从20到54平方公里不等的庄园中，分别对柳雷鸟（矛隼）进行了0%、15%和30%的实验性捕猎。种群越冬增长率强烈负密度依赖，但尽管如此，与早期研究结果相反，只有33%的捕猎量得到了补偿。补偿不足可能是由于幼鸟远距离扩散不受捕猎影响所致。大规模管理实验对于检测捕猎影响的必要性得到了明确证明：只有当我们使用整个数据集时才发现补偿不足，而按年份或区组分析数据时则未发现。我们的研究表明，很难证明一个种群不存在捕猎补偿，并警告不要将小规模、非季节性或重复不佳的研究作为未来捕猎管理决策的依据。
