Forest structure drives global diversity of primates

Abstract

Summary1. Geographic gradients in the species richness of non-human primates have traditionally been attributed to the variation in forest productivity (related to precipitation levels), although an all-inclusive, global-scale analysis has never been conducted. 2. We perform a more comprehensive test on the role of precipitation and biomass production and propose an alternative hypothesis -the variation in vertical structure of forest habitats as measured by forest canopy height -in determining primate species richness on a global scale. 3. Considering the potential causal relationships among precipitation, productivity and forest structure, we arranged these variables within a path framework to assess their direct and indirect associations with the pattern of primate species richness using structural equation modelling. The analysis also accounted for the influence of spatial autocorrelation in the relationships and assessed possible historical differences among biogeographical regions. 4. The path coefficients indicate that forest canopy height (used as a proxy for vertical forest structure) is a better predictor of primate species richness than either precipitation or productivity on both global and continental scales. The only exception was Asia, where precipitation prevailed, albeit independently from productivity or forest structure. The influence of spatially structured processes varied markedly among biogeographical regions. 5. Our results challenge the traditional rainfall-based viewpoint in favour of forest distribution and structure as primary drivers of primate species richness, which aggregate potential effects from both climatic factors and habitat complexity. These findings may support predictions of the impact of forest removal on primate species richness.

Canopy structure drives orangutan habitat selection in disturbed Bornean forests

“…Moreover, forest structure (measured as canopy height) is a more important determinant of global primate species richness than productivity or rainfall (18). However, contrary to our predictions and findings for many other species (17), canopy vertical complexity was unimportant in orangutan habitat selection.…”

“…Animals, particularly arboreal primates, interact with 3D vegetation structure in direct (e.g., climbing, traveling) and indirect (e.g., selecting structurally induced microclimates) ways, making vegetation structure an important component of their habitat (17,18). However, measuring canopy 3D structure is challenging, especially at spatial scales appropriate for large mammals.…”

Impending extinction crisis of the world’s primates: Why primates matter

“…Edge effects predominate in many areas of disturbed forests, exacerbating habitat degradation ( 37 ). Agricultural expansion as well as legal and illegal logging cause further desiccation of vegetation, and human-induced forest fires devastate large areas in primate range regions yearly, resulting in increased tree mortality and losses of up to one-third of canopy cover ( 46 , 47 ). Although the effects of habitat loss, fragmentation, and degradation upon primates are mediated by variations in species-specific traits (rarity, trophic levels, dispersal mode, reproductive biology, life history, diet, and ranging behavior), the common response across taxa is population decline (Fig.…”

Canopy height explains species richness in the largest clade of Neotropical lianas

“…One possibility is to use proxies of vegetation structure such as canopy height, which can be derived from spaceborne light detection and ranging (LiDAR; Lefsky, 2010;Simard, Pinto, Fisher, & Baccini, 2011). Such canopy height estimates can then be used to test hypotheses concerning the relationship between 3-D habitat structure and the distribution and diversity of organisms (Couvreur et al, 2015;Gouveia et al, 2014;Oliveira & Scheffers, 2019).…”