Native habitat and protected area size matters: Preserving mammalian assemblages in the Maputaland Conservation Unit of South Africa

Identifying unique habitats that support intact mammal assemblages help to prioritize conservation areas. Over time, modifications of native habitats in multi-functional Protected Areas (PAs) can drive changes in mammal populations. We assessed mammalian richness across PA sizes and multi-species occupancy in various habitats, including plantations, in the Maputaland Conservation Unit, South Africa. We collected data from six camera-trap surveys (205 camera-trap stations) between 2013 and 2014 covering PAs that varied in size, habitat diversity and disturbance levels. We included eight habitat covariates for occupancy estimation and narrow vs. wider path as detection covariates. We applied the Royle-Nichols multi-session multi-species hierarchical model to estimate species richness and occupancy dynamics of 39 mammalian species for different PAs, while accounting for imperfect detection. Species richness increased with protected area size. Most large mammals were absent in the smallest PA. Detection probabilities for 90% of the species were <0.10 and showed considerable species-specific detection rates on both narrow and wide paths. High occupancy (>0.40) was estimated for 16 species in grassland and plantation, followed by woodland (15), sand forest (14), coastal lowland forest and dune forests (13 species each), Makatini clay thicket (12) and dry forest thicket (10). Plantation had higher mammal occupancy, presumably attributed to the edge effects of adjacent natural habitats, and the understory grass cover in abandoned and immature plantations. Our findings provided comprehensive inferences on community-wide assemblages for valuable management decision making.