3/24/2023 0 Comments Ninox symbol for not equalDominant predators preferentially occupy the most productive areas, leaving less productive areas for subordinate species, leading to spatial partitioning (Durant, 2000). Temporal partitioning can reduce both resource and interference competition, regardless of which form of competition was the catalyst for these changes (Kronfeld‐Schor & Dayan, 1999). Niche partitioning by coexisting predators can occur in time, space, and resources. This process of partitioning resources, known as niche differentiation, prevents the extirpation of the subordinate predator, as would otherwise be predicted by the competitive exclusion principle (Schoener, 1974). Mesopredators, in turn, reduce the risk of agonistic encounters by deviating from an optimum resource gathering strategy (Pianka, 1974 Ritchie & Johnson, 2009). Apex predators suppress subordinate mesopredators directly through agonistic encounters or indirectly by reducing resource availability (Ritchie & Johnson, 2009). Predators are an important driving force in ecosystems, regulating food webs and the distribution of resources (Terborgh & Estes, 2010). Niche partitioning among invasive predators facilitates coexistence, but simultaneously intensifies predation pressure on vulnerable native species. We suggest there is spatial and resource partitioning within the invasive predator guild, but that this is incomplete, and avoidance is achieved by temporal partitioning within overlapping areas. Stoats were only recorded at the treatment site after both larger predators were removed, becoming the most frequently detected predator at 6 months post‐perturbation. Mesopredators adjusted their behavior to reduce the risk of interference competition, thereby restricting access to abundant prey but increasing predation pressure on diurnal native birds. We found compelling evidence of niche partitioning spatiotemporal activity of apex predators maximized access to abundant invasive prey, with ferrets targeting lagomorphs and cats targeting rodents. Further, we tested for mesopredator release by selectively removing cats and ferrets in a pulse perturbation experiment. Over 4405 camera‐trap days, we assessed interactions among three invasive predators: two apex predators (feral cats Felis catus and ferrets Mustela furo) and a mesopredator (stoats Mustela erminea), in relation to their primary prey (lagomorphs, rodents and birds) and habitat use. We investigated whether niche partitioning exists within a guild of invasive mammalian predators and determined the consequences for native species. Competitive interactions are particularly important in invaded ecosystems where introduced predators can suppress native prey species. Predators compete aggressively for resources, establishing trophic hierarchies that influence ecosystem structure.
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