Unveiling the drivers of local dung beetle species richness in the Neotropics

Abstract

Aim Nearly 40 different hypotheses have been put forward to explain the latitudinal diversity gradient, implying that geographical variations of biodiversity may be the result of a complex array of factors affecting organisms in different ways. Our main goal was to identify the most important drivers of local dung beetle species richness in the Neotropics. Location Neotropics. Taxon Dung Beetles (Coleoptera: Scarabaeinae). Methods We used a multi‐model approach to identify which potential drivers correlate better with the variations in local dung beetle species richness. We surveyed published literature on dung beetle communities to extract information on species richness, abundance, type of bait, type of habitat and sampling effort (as hours/pitfall) for different localities, discarding sites with low sampling effort. We used environmental variables to account for six possible explanations of species richness gradients: productivity, water–energy, ambient energy, habitat heterogeneity, resource heterogeneity and seasonality, as well as spatial data to account for other geographically structured phenomena. We used mixed models—with abundance, ecoregion and bait type as random factors—to select the best model among the variables accounting for each explanation. Finally, we used structural equation models to assess which explanations are associated with variations in dung beetle diversity and how they interact. Results Resource heterogeneity was the best single correlate of dung beetle richness. However, the best multiple model comprises three different explanations: productivity, resource heterogeneity and other spatially structured factors. Structural equation models show that abundance is directly (positively) associated with richness, followed by primary productivity and soil variables (a proxy for environmental heterogeneity), together with mammal richness, (a proxy for resource heterogeneity). Main conclusions Several explanations need to be considered to account for Scarabaeinae local richness patterns. The diversity of dung beetle communities correlates with the interaction of water–energy dynamics and heterogeneity in both resources and habitats. However, while heterogeneity variables are directly associated with richness, energy relates with it through abundance, and water through resource diversity.

Dung beetle β‐diversity across Brazilian tropical dry forests does not support the Pleistocene Arc hypothesis

“…However, no large-scale latitudinal or longitudinal patterns across TDFs have been explored so far. Pessôa et al (2021) evaluated the drivers of dung beetle richness across the neotropics and found that several explanations need to be considered to account for Scarabaeinae local richness patterns. These authors found that local richness and abundance of dung beetle assemblages correlates with the interaction of water-energy dynamics and heterogeneity in both resources and habitats.…”

“…2019; Pessôa et al . 2021). These variables are important drivers of biological diversity during and after the LGM (Collevatti et al .…”

“…If more recent ecological processes determine the number and composition of species in an area, then species richness reflects the properties of the ecosystem. Thus, some factors such as climate, resource availability and environmental heterogeneity could determine the local structure of communities (Andresen 2008;Pessôa et al 2021). These factors would then be more important than biogeographic and evolutionary ones to explain the current distribution and compositional patterns found in TDFs after the LGM and the establishment in South America of a latitudinal gradient of temperature and precipitation different from when the climate was dry and cold.…”

“…Several scarabaeine beetles show habitat specificity, being unable to extend their populations to different habitats (Klein 1989;Halffter 1991). Climatic factors, such as temperature and precipitation, are also known to affect dung beetle distribution locally (da Silva et al 2013;Novais et al 2016) but also across wide latitudinal gradients (Bogoni et al 2019;Pessôa et al 2021). These variables are important drivers of biological diversity during and after the LGM (Collevatti et al 2013;Arruda et al 2018).…”

Environmental drivers of taxonomic and functional diversity of dung beetles across a chronosequence of tropical grasslands with different cattle grazing removal ages

“…2019; Pessôa et al . 2021). Furthermore, dung beetles exhibit wide variation in life history strategies and body sizes that are reflected in easily measurable functional traits (Halffter & Edmonds 1982; Hanski & Cambefort 1991), being considered adequate models to evaluate the effects of anthropogenic actions on ecosystem processes (Audino et al .…”