Occupancy Modeling Reveals Interspecific Variation in Habitat Use and Negative Effects of Dogs on Lemur Populations

Abstract

Effective, targeted management and conservation plans for wildlife populations require reliable population sampling and estimation. Unfortunately, robust, comprehensive primate population estimates are often lacking, particularly for rare, elusive species. Historically, population estimates of primates have relied on labor-intensive line-transect sampling and distance estimation techniques. We used occupancy sampling to estimate the probability of occupancy and detection of seven lemur species in Ranomafana National Park, Madagascar, and explore relationships between occupancy and detection and landscape, habitat, and co-occurring species variables. We detected and provide estimates of occupancy and/or detection for seven lemur species in a World Heritage Site: Ranomafana National Park, Madagascar. We found habitat type was an important variable explaining occupancy patterns for detection of golden bamboo lemur (Hapalemur aureus), as well as red bellied lemur (Eulemur rubriventer) and black-and-white ruffed lemur (Varecia variegata). The presence of free-ranging dogs (Canis familiaris) was an important factor in several competing models for red-bellied lemurs and eastern lesser bamboo lemurs (Hapalemur griseus), highlighting the threat posed by this exotic predator to primates. While some estimates had error values overlapping zero, reflecting the rarity and low detection of these species, these results indicate the importance of protecting multiple forest types to maintain lemur biodiversity and the underappreciated conservation threat of invasive species in Madagascar.