Primary productivity and habitat protection predict elevational species richness and community biomass of large mammals on Mt. Kilimanjaro

Abstract

1. Despite their diversity and their large functional and cultural importance, the patterns and predictors of large mammal diversity along elevational gradients on tropical mountains remain poorly understood. Today, large mammals are threatened by human disturbances such as habitat destruction and hunting and may increasingly depend on the conservation of protected areas.2. Here, we use field data on the diversity of large mammals along a 3.6 km elevational gradient on Mt. Kilimanjaro to evaluate the importance of climate, net primary productivity and human impact for the distribution, species richness and community biomass of wild mammals.3. Mammal species richness was explored with camera traps on 66 study plots along an elevational gradient from 870 to 4,550 m a.s.l.. We applied path analysis and variance partitioning analysis to unravel the direct and indirect effects of temperature, precipitation, primary productivity, land use, land area, the protection of habitats and the occurrence of domestic mammals on the diversity of wild mammals. 4. Both species richness and community biomass of wild mammals showed a unimodal distribution with elevation, peaking in the montane zone of Mt. Kilimanjaro.However, the peak shifted significantly to lower elevations when only protected habitats were considered. Wild mammal diversity increased with net primary productivity, protection of habitats and temperature. 5.Our study underscores the importance of energy resources for the establishment of diversity gradients in large mammals. While temperature has been revealed as a direct predictor of diversity in most ectothermic taxa, in endothermic organisms temperature has stronger indirect effects, via a modulation of net primary productivity. Moreover, our study reveals how patterns of diversity on tropical mountains are influenced by human impact, pointing to the pivotal role of protected areas for the long-term conservation of mountain biodiversity.

Human disturbance and prey occupancy as predictors of carnivore richness and biomass in a Himalayan hotspot

“…Coinciding with our predictions, muntjac occupancy was positively correlated with NPP, supporting the view that productive ecosystems sustain higher level of biodiversity than less productive ecosystems (Gebert et al , 2019). Surprisingly, livestock occupancy had no significant effects on muntjac occupancy.…”

“…On each camera trapping site, carnivore species richness was obtained by counting the number of carnivore species recorded during the study period. Community biomass was computed by summing up the body weight of the individuals of all carnivore species across hourly event counts (Gebert et al , 2019). We sourced the EltonTraits database (Wilman et al , 2014) for mean body mass of the carnivores recorded by our camera traps (Table ).…”

“…For example availability of food plants can be a limiting factor for the distribution of animal consumers (Wisz et al , 2013). Numerous studies have also suggested that availability of energy resources is a key driver shaping species richness (Gebert et al , 2019). Highly productive ecosystems are hypothesized to have higher energy resources and thus be able to sustain more abundant populations than less productive ecosystems (Hurlbert & Stegen, 2014).…”

Habitat amount and ambient temperature dictate patterns of anuran diversity along a subtropical elevational gradient

“…The mid‐elevational peak in species richness we found here is consistent with previous studies on vertebrate elevational ranges, for which this pattern is considered to be the most pervasive (e.g. Gebert et al., 2019; McCain, 2010; McCain & Grytnes, 2010). In terms of anurans, most elevational gradients worldwide show a curvilinear relationship between species richness and elevation for these ectotherm vertebrates (McCain & Sanders, 2010).…”

Testing Huston's dynamic equilibrium model along fire and forest productivity gradients using avian monitoring data

“…Productivity is often used to describe the growth rate of plants via biomass accumulation and represents a measure of energy available to plants and the broader community of primary and secondary consumers (Putman & Wratten, 1984). Though initially used to explain patterns in plant species richness, productivity has also been used extensively in studies on the distribution of animals, typically by remotely sensed data such as the Normalized Difference Vegetation Index (NDVI, Crego et al., 2020; Pettorelli et al., 2011) or net/gross primary productivity (NPP/GPP, Cusens et al., 2012; Gebert et al., 2019; Rosenzweig, 1995).…”