Context: Primates are an important component of biodiversity in tropical regions. However, many studies on the effects of habitat change on primates ignore the relative 5 influence of landscape composition and configuration. Objectives: This study addresses the question: how important are landscape-scale forest area and composition relative to patch-scale (1 -1080 ha) and site-scale (transect of 1 km) habitat variables for the occupancy and abundance of four primate species in the Colombian Llanos.10 Methods: Using a randomly stratified survey design, 81 fragments were surveyed for primate occupancy and abundance. We used zero-inflated models to test the relative influence of landscape-scale, patch-scale and site-scale variables on occupancy and abundance for each species. A 95% confidence set of models was constructed using the cumulative Akaike weight for each model and the relative importance of each set of 15 variables calculated for each primate species. Results: Occupancy was determined by a combination of site-scale, patch-scale and landscape-scale variables but this varied substantially among the primate species.Conclusion: Our study highlights the importance of managing primates at a range of scales that considers the relative importance of site-, patch-and landscape-scale 20 variables.

Habitat loss and fragmentation are significant threats for primate species worldwide. However, few attempts have been made to look for general patterns in primate responses to habitat loss and fragmentation, or whether these may be associated with species' traits. We conducted a review of published literature on effects of patch size to quantify the effect of a reduction in this predictor on primates, and to determine whether these effects depend on species' traits. The effects of patch size on seven response variables (density, parasite prevalence and diversity, presence, genetic diversity, time spent feeding, resting and movement), were extracted from 135 papers and compared across six species traits (diet specialisation, social structure, body size, home range size, group size and dispersal ability). We found that density, parasitic prevalence and diversity and time spent feeding were positively associated with a reduction in patch size, while species' presence and genetic diversity were negatively associated. Time spent resting and moving did not show clear patterns. We found little evidence that the effect of patch size varies consistently with traits. This study provides important evidence for the consistent effect of patch size on a range of factors that influence the dynamics of primate populations. However, there is a need to move beyond quantifying patch size effects alone and to quantify the effects of changes occurring at broader landscape scales. This would allow more holistic primate conservation strategies to be developed across whole landscapes rather than being focussed on the management of individual patches.

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.

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