Rioux Ève, Pelletier Fanie, St-Laurent Martin-Hugues
Département de Biologie, Chimie et Géographie Centre for Northern Studies & Centre for Forest Research Université du Québec à Rimouski Rimouski Québec Canada.
Département de biologie Centre for Northern Studies Université de Sherbrooke Sherbrooke Québec Canada.
Ecol Evol. 2022 Mar 18;12(3):e8742. doi: 10.1002/ece3.8742. eCollection 2022 Mar.
Documenting trophic niche partitioning and resource use within a community is critical to evaluate underlying mechanisms of coexistence, competition, or predation. Detailed knowledge about foraging is essential as it may influence the vital rates, which, in turn, can affect trophic relationships between species, and population dynamics. The aims of this study were to evaluate resource and trophic niche partitioning in summer/autumn between the endangered Atlantic-Gaspésie caribou () population, moose () and their incidental predators, the black bear () and coyote (), and to quantify the extent to which these predators consumed caribou. Bayesian isotopic analysis showed a small overlap in trophic niche for the two sympatric ungulates suggesting a low potential for resource competition. Our results also revealed that caribou occupied a larger isotopic niche area than moose, suggesting a greater diversity of resources used by caribou. Not surprisingly, coyotes consumed mainly deer (), moose, snowshoe hare (), and occasionally caribou, while bears consumed mainly vegetation and, to a lesser extent, moose and caribou. As coyotes and bears also feed on plant species, we documented trophic niche overlap between caribou and their predators, as searching for similar resources can force them to use the same habitats and thus increase the encounter rate and, ultimately, mortality risk for caribou. Although the decline in the Gaspésie caribou population is mostly driven by habitat-mediated predation, we found evidence that the low level of resource competition with moose, added to the shared resources with incidental predators, mainly bears, may contribute to jeopardize the recovery of this endangered caribou population. Highlighting the trophic interaction between species is needed to establish efficient conservation and management strategies to insure the persistence of endangered populations. The comparison of trophic niches of species sharing the same habitat or resources is fundamental to evaluate the mechanisms of coexistence or competition and eventually predict the consequences of ecosystem changes in the community.
记录一个群落内的营养生态位划分和资源利用情况对于评估共存、竞争或捕食的潜在机制至关重要。关于觅食的详细知识至关重要，因为它可能影响生命率，进而影响物种间的营养关系和种群动态。本研究的目的是评估濒危的大西洋加斯佩半岛驯鹿种群、驼鹿及其偶然捕食者黑熊和郊狼在夏秋季节的资源和营养生态位划分，并量化这些捕食者捕食驯鹿的程度。贝叶斯同位素分析表明，这两种同域有蹄类动物的营养生态位重叠较小，表明资源竞争潜力较低。我们的结果还表明，驯鹿占据的同位素生态位面积比驼鹿大，这表明驯鹿使用的资源种类更多样。不出所料，郊狼主要捕食鹿、驼鹿、雪鞋兔，偶尔也捕食驯鹿，而熊主要以植被为食，其次是驼鹿和驯鹿。由于郊狼和熊也以植物物种为食，我们记录了驯鹿与其捕食者之间的营养生态位重叠，因为寻找相似资源会迫使它们使用相同的栖息地，从而增加相遇率，并最终增加驯鹿的死亡风险。尽管加斯佩半岛驯鹿种群的减少主要是由栖息地介导的捕食造成的，但我们发现有证据表明，与驼鹿的低水平资源竞争，加上与偶然捕食者（主要是熊）的共享资源，可能会危及这一濒危驯鹿种群的恢复。突出物种间的营养相互作用对于制定有效的保护和管理策略以确保濒危种群的持续存在是必要的。比较共享相同栖息地或资源的物种的营养生态位对于评估共存或竞争机制并最终预测群落中生态系统变化的后果至关重要。
