Distribution and conservation status of the endangered Montagne d'Ambre fork-marked lemur (Phaner electromontis)

The geographic distribution of a species can provide insights into its population size, ecology, evolution, and how it responded to past (and may respond to future) environmental change. Improving our knowledge of the distribution of threatened species thus is a high priority in assessing their conservation status. However, there are few data available for many recently described yet understudied and potentially threatened primate taxa, making their conservation difficult. Here, we investigated the distribution of the Montagne d'Ambre fork-marked lemur, Phaner electromontis, a threatened nocturnal primate endemic to northern Madagascar and classified as Endangered by the IUCN. Because fork-marked lemurs are highly vocal, we used acoustic surveys to assess the species' presence-absence and relative population density within 66 distinct forest survey sites in northern Madagascar. Further, we compared data among five forest types within the study area and investigated the relationship between relative population density and climate variables. We report the presence of P. electromontis in 22 study sites; several of these populations were unknown previously. Although we found P. electromontis most frequently in dry-transitional forests, our results suggest that geography (spatial autocorrelation) rather than environmental variables explains the species' distribution. We hypothesize that environmental unpredictability and gummivory, combined with the presence of several distinct Phaner species in the studied area, could explain the observed distribution.