Canada Research Chair on Northern Biodiversity and Centre d'Études Nordiques, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, G5L3A1, Canada.
Département de biologie and Centre d'Études Nordiques, Université Laval, 1045 avenue de la Médecine, Pavillon Vachon, Quebec City, QC, G1V0A6, Canada.
Oecologia. 2020 Jul;193(3):557-569. doi: 10.1007/s00442-020-04696-8. Epub 2020 Jun 28.
As top or mesopredators, carnivores play a key role in food webs. Their survival and reproduction are usually thought to be influenced by prey availability. However, simultaneous monitoring of prey and predators is difficult, making it challenging to evaluate the impacts of prey on carnivores' demography. Using 13 years of field data on arctic foxes Vulpes lagopus in the Canadian High Arctic and a capture-recapture multi-event statistical approach, we investigated the hypothesis that increases in lemming abundance (a cyclic and unpredictable food source) and goose colony proximity (a stable but spatially and temporally limited food source) would be associated with increased apparent survival and reproduction probabilities of adults. Adult apparent survival varied greatly across years (0.13-1.00) but was neither affected by lemming nor goose variations in abundance. However, reproduction probabilities were strongly influenced by both lemming abundance and access to the goose colony. A fox breeding in the best conditions of food availability (year of high lemming density inside the goose colony) had a reproduction probability four times higher than one experiencing the worst conditions (year of low lemming density outside the goose colony). Breeding status of individuals also played a role, with breeders having a 10-20% higher probability of survival and 30% higher probability of reproduction the following year than non-breeders. As the Arctic ecosystem changes due to increased temperatures and species ranges, this study will allow better predictions of predator responses to management or environmental changes and a better understanding of ecosystem functioning.
作为顶级或中层捕食者，肉食动物在食物网中起着关键作用。它们的生存和繁殖通常被认为受到猎物丰度的影响。然而，同时监测猎物和捕食者是困难的，这使得评估猎物对捕食者种群动态的影响具有挑战性。利用加拿大北极地区北极狐 Vulpes lagopus 的 13 年野外数据和捕获-再捕获多事件统计方法，我们调查了以下假设：旅鼠丰度（周期性和不可预测的食物源）的增加和鹅群的接近（稳定但空间和时间有限的食物源）与成年狐的明显生存和繁殖概率增加有关。成年狐的明显存活率在不同年份差异很大（0.13-1.00），但不受旅鼠或鹅丰度变化的影响。然而，繁殖概率受到旅鼠丰度和接近鹅群的强烈影响。在食物供应最佳条件下（鹅群内旅鼠密度高的年份）繁殖的狐狸，其繁殖概率比在最不利条件下（鹅群外旅鼠密度低的年份）繁殖的狐狸高四倍。个体的繁殖状态也起作用，繁殖者的存活率比非繁殖者高 10-20%，繁殖率高 30%。由于温度升高和物种分布范围的变化导致北极生态系统发生变化，这项研究将能够更好地预测捕食者对管理或环境变化的反应，并更好地理解生态系统的功能。
