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Madagascar is experiencing some of the most persistent and alarming rates of anthropogenic forest loss, threatening its endemic flora and fauna. Numerous factors contribute to this forest degradation and loss, but in Madagascar it is most often attributed to heavy human reliance on forest products for income and survival. Montagne des Français (MDF) is a forest in northern Madagascar and the last remaining home of the Critically Endangered northern sportive lemur (Lepilemur septentrionalis). We assessed the type and frequency of anthropogenic disturbances observed at MDF, as well as the forest loss and fragmentation in this region over six decades. To assess current conditions, we systematically recorded occurrences of anthropogenic disturbances in ten lemur home ranges and three trails over two field seasons (June to July 2016; February to May 2017). To assess historical landcover change, we analyzed six, classified, 30-m resolution forest cover maps from 1953, 1973, 1990, 2000, 2010 and 2014. We recorded a total of 1,412 human-caused disturbances of eight different types in about 15 ha. Felled trees were the most frequently observed disturbance, with Bonaramatsigny (Leucaena leucocephala) the most frequently felled species. Forest cover at MDF drastically decreased from 76% in 1953, to 24% in 2014. Our results indicate that human disturbances are widespread and pervasive, contributing to overall forest cover loss and fragmentation at MDF, which impact the quality, connectivity, and availability of habitat for endemic lemurs of this region. [ABSTRACT FROM AUTHOR]

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use.

We provide male and female census count data, age-specific survivorship, and female age-specific fertility estimates for populations of seven wild primates that have been continuously monitored for at least 29 years: sifaka (Propithecus verreauxi) in Madagascar; muriqui (Brachyteles hypoxanthus) in Brazil; capuchin (Cebus capucinus) in Costa Rica; baboon (Papio cynocephalus) and blue monkey (Cercopithecus mitis) in Kenya; chimpanzee (Pan troglodytes) in Tanzania; and gorilla (Gorilla beringei) in Rwanda. Using one-year age-class intervals, we computed point estimates of age-specific survival for both sexes. In all species, our survival estimates for the dispersing sex are affected by heavy censoring. We also calculated reproductive value, life expectancy, and mortality hazards for females. We used bootstrapping to place confidence intervals on life-table summary metrics (R0, the net reproductive rate; λ, the population growth rate; and G, the generation time). These data have high potential for reuse; they derive from continuous population monitoring of long-lived organisms and will be invaluable for addressing questions about comparative demography, primate conservation and human evolution.