Exploring the effects of anthropogenic habitat change on Euplerid carnivore occupancy in a humid evergreen forest, south-east Madagascar

Mammalian carnivores are vulnerable to anthropogenic pressures, including habitat modifications, disturbance, and the introduction of non-native species. Forests throughout Madagascar are under persistent pressure from extraction of timber and non-timber products, and conversion of forest habitat to agriculture. Yet research into the impact of anthropogenic pressures on endemic carnivores is only recent, and relatively little is known about their populations in the extreme south of the island. We sought to explore how disturbance affects the occurrence of small carnivores in lowland humid forests and their varying degrees of adaptability to human-modified landscapes. To answer this, we conducted exploratory camera trap surveys of endemic Euplerid carnivores at two sites in Tsitongambarika Nouvelle Aire Protégée, between July 2019 and February 2020. We confirmed the presence of four Euplerid species at both survey sites, that is, fosa (Cryptoprocta ferox), spotted fanaloka (Fossa fossana), ring-tailed vontsira (Galidia elegans), and broad-striped vontsira (Galidictis fasciata), and three non-native carnivore species, that is, small Indian civet (Viverricula indica), domestic dog (Canis familiaris), and exotic/feral cat (Felis sp.). We used single-species, single-season occupancy modeling to predict the occurrence of the four Euplerids, using covariates relating to habitat degradation and human disturbance to test the anthropogenic factors that best predicted their use of landscape. We recorded high occupancy levels of all four native species, suggesting that the intact interior of Tsitongambarika continues to support viable populations. However, similar to research in other Malagasy forests, our modeling suggests that the occurrence of spotted fanaloka and fosa is negatively affected by forest degradation, though ring-tailed vontsira show some evidence of flexibility to degraded habitat. We highlight the need to prioritize small carnivore conservation in Tsitongambarika and recommend that urgent measures be taken to reduce habitat degradation and the incursion of invasive species. Without targeted action, human activities will precipitate the local extinction of Euplerids.