Habitat as a mediator of mesopredator‐driven mammal extinction

Abstract

A prevailing view in dryland systems is that mammals are constrained by the scarcity of fertile soils and primary productivity. An alternative view is that predation is a primary driver of mammal assemblages, especially in Australia, where 2 introduced mesopredators-feral cat (Felis catus) and red fox (Vulpes vulpes)-are responsible for severe declines of dryland mammals. We evaluated productivity and predation as drivers of native mammal assemblage structure in dryland Australia. We used new data from 90 sites to examine the divers of extant mammal species richness and reconstructed historic mammal assemblages to determine proportional loss of mammal species across broad habitat types (landform and vegetation communities). Predation was supported as a major driver of extant mammal richness, but its effect was strongly mediated by habitat. Areas that were rugged or had dense grass cover supported more mammal species than the more productive and topographically simple areas. Twelve species in the critical weight range (CWR) (35-5500 g) that is most vulnerable to mesopredator predation were extirpated from the continent's central region, and the severity of loss of species correlated negatively with ruggedness and positively with productivity. Based on previous studies, we expect that habitat mediates predation from red foxes and feral cats because it affects these species' densities and foraging efficiency. Large areas of rugged terrain provided vital refuge for Australian dryland mammals, and we predict such areas will support the persistence of CWR species in the face of ongoing mammal declines elsewhere in Australia.

Determining carnivore habitat use in a rubber/forest landscape in Brazil using multispecies occupancy models

“…Responses of mammalian carnivores to agricultural lands vary, depending not only on the type of cultivar and the amount and configuration of native vegetation remaining in the matrix, but also on the ecology of each species [ 1 – 3 ]. Species responses to land conversion resulting in differential habitat use may modulate intra/interspecific interactions, and thus influence the effect of the species on other tropic levels [ 4 – 6 ]. Given that predators play critical roles in ecosystem structure and function [ 7 ], devising land management strategies for carnivore conservation in agricultural landscapes requires investigations of habitat use on each carnivore species in the community.…”

Using camera traps to investigate spatial co‐occurrence between exotic predators and native prey species: a case study from northeastern Madagascar

“…Hradsky et al ., ; Paschoal et al ., ). We've recorded a higher exotic predator occupancy in more degraded sites (Farris et al ., ), suggesting that as habitat degradation increases, native species face decreased habitat quality and increased exotic predator presence, which can amplify negative effects on native species (Brook, Sodhi & Bradshaw, ; Anson et al ., ; Doherty et al ., ; McDonald et al ., ). As primary rainforest becomes further degraded and exotic predators increase their presence in the region, it is entirely possible that native species populations will show intense declines.…”

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian Wet Tropics

“…In the context of the AWT, higher ruggedness values are likely indicative of boulder fields and steep drop‐offs in the environment. Most previous studies in Australia concluded that feral cats avoid topographically complex areas due to a reduction in hunting success in more structurally complex habitats (Hohnen et al, 2016; McDonald et al, 2017; McGregor, Legge, Potts, et al, 2015; McGregor et al, 2014). Due to sparse literature on feral cat ecology in rainforests, we can only hypothesize why feral cats in our study system might prefer more topographically complex terrain.…”