The effect of top predator removal on the distribution of a mesocarnivore and nest survival of an endangered shorebird

Avian Conservation and Ecology

article

Michelle L. Stantial¹  Abigail J. Darrah²  Shannon L. Farrell¹  Brooke Maslo³ 

[1] Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry;Audubon Mississippi, Coastal Bird Stewardship Program;Rutgers, The State University of New Jersey, Department of Ecology

关键词: American mink;    endangered species;    habitat use;    mesopredator release hypothesis;    multispecies occupancy;    piping plover;    red fox;    trophic cascade;   

DOI  :  10.5751/ACE-01806-160108

学科分类：口腔科学

来源: Resilience Alliance Publications

【 摘 要 】

For trophic systems regulated by top-down processes, top carnivores may determine species composition of lower trophic levels. Removal of top predators could therefore cause a shift in community composition. If predators play a role in limiting the population of endangered prey animals, removing carnivores may have unintended consequences for conservation. Lethal predator removal to benefit prey species is a widely used management strategy. Red foxes (Vulpes vulpes) are a common nest predator of threatened piping plovers (Charadrius melodus) and are often the primary target of predator removal programs, yet predation remains the number one cause of piping plover nest loss. Predator exclusion cages (hereafter, exclosures) around nests are often used to keep foxes from eating eggs, as an alternative to predator removal. Fox removals may increase the presence or activity of smaller predators, including American mink (Neovison vison), which can enter exclosures. We predicted that when foxes were removed from plover breeding sites, mesopredator release of mink would occur and lead to increased predation levels of plover nests. Average probability of mink occupancy was higher when foxes were absent (0.26 [95% BCI = 0.16, 0.38]) than when they were present (0.04 [0.01, 0.09]). For nests not protected by exclosures, nest predation was similar at sites with (0.42 [0.12, 0.68]) and without foxes (0.38 [0.10, 0.64]). At sites where foxes were absent, however, predation rates of exclosed nests were 3-fold higher (foxes absent [0.25 {0.06, 0.52}]) compared to sites where foxes remained [0.06 {0.01, 0.18}]). Our results suggest that removal of foxes from plover breeding sites allowed American mink to expand their local range. In turn, removal of foxes led to a decrease in nest survival of an endangered ground-nesting bird. Conservation within complex trophic systems may fail if interactions among species are not well understood when implementing lethal predator removal.

【 授权许可】

CC BY