Habitat loss, illegal hunting, and climate change pose a threat to terrestrial mammals worldwide. Tropical terrestrial mammals comprise high species richness and abundance communities that are highly vulnerable to habitat loss due to high rates of deforestation and illegal hunting in these ecosystems. Protected areas represent an effective conservation strategy for biodiversity protection. The Calakmul Biosphere Reserve (CBR) located in southern Mexico is the largest protected area decreed in the tropical region. We surveyed the diversity, richness and spatiotemporal abundance of species of medium and large mammals inside and outside the Calakmul Biosphere Reserve in the Maya Forest, using camera traps between 2016 and 2022. A cumulative effort of 8,300 days per camera trap with 9,821 independent events were obtained corresponding to 28 species from eight taxonomic Orders; most records were from inside the CBR. Generalist species as well as other species with a restrictive occurrence were identified. Spatial differences in mammal composition were observed inside and outside the Calakmul Biosphere Reserve, reflecting differentiated patterns of habitat occupation and use. Temporal variations in mammal communities were detected, possibly associated with the availability of water and extreme climatic events. Although the specific richness was higher inside the CBR, the uniformity in the distribution of abundances was higher in external sites. Our results underscore the key role of the CBR in the conservation of terrestrial mammals, as well as the complementary value of community-managed territories. The presence of threatened species such as Panthera onca, Tapirus bairdii and Tayassu pecari reaffirms the strategic importance of the CBR for medium-to-large sized terrestrial mammals in Mexico.

Habitat loss threatens biodiversity worldwide being particularly detrimental in tropical rainforest where a cumulative deforestation expands for decades. Tropical rainforests harbor a rich mammal diversity with a wide range of species using different habitats, ranging from forest-dwelling to arboreal species. Recent techniques as camera trapping have proven useful to study the ecology of arboreal mammals. Here we assessed the overall community structure of arboreal mammals in a protected area by analyzing patterns of diversity and abundance and their spatial and seasonal variations. A total of 21 camera-trapping stations were set in clusters in three zones. Spatial and seasonal alpha diversity, and community evenness patterns were estimated using Hill’s numbers, and Sørensen’s dissimilarities were used as a proxy to estimate beta diversity. A relative abundance index was calculated for each species, at each site and season. To estimate the influence of spatial and tree-morphology on arboreal use by mammals, linear regressions were performed for species richness, evenness, and abundance; logistic regression were used to test correlations with presence/absence data. We observed a high species richness (14 species) of arboreal mammals. Species richness remained similar between sites, although shifts in abundances, and a decreasing gradient in community evenness related to distance of camera trap station located in each site were observed. We observed a high and low diversity dissimilarity between camera trap stations and between sites, respectively. Seasonality showed no significant effect over abundance, alpha and beta diversities. Linear and logistic regression of arboreal use by mammals was determined by several environmental variables. This protected area holds the natural habitat conditions to ensure the persistence of this rich arboreal mammal community.