Evidence of species sorting driving aquatic beetles associated with woody debris in a transitional region between Cerrado and Atlantic Forest biomes

Abstract

We investigated (1) the variation of both species composition and species relative abundances of aquatic beetles associated with submerged woody debris in a transitional region between Cerrado (Brazilian savannah) and Atlantic Forest biomes; and (2) which assembling processes are more associated with the observed patterns, species sorting or mass effects. We hypothesized that the marked differences between Cerrado and Atlantic Forest streams regarding vegetation composition and structure would produce different environmental conditions for stream beetle faunas assembling. We used spatial explicit multivariate techniques to analyze whether metacommunity patterns were more associated with environmental variables, indicating a major role of species sorting, or with spatial variables, indicating intense dispersal. We found distinct communities within each biome in terms of both changes in taxonomic composition and species relative abundance driven by environmental factors. Biome type, a regional scale variable, and variation in dissolved oxygen levels, a local scale variable, were the best explanatory variables of variation in metacommunity structure. We did not find any evidence of the influence of processes related to the spatial configuration of streams. Altogether our results pointed to species sorting structuring saproxylic beetles assemblages patterns.

Metacommunity detectives: Confronting models based on niche and stochastic assembly scenarios with empirical data from a tropical stream network

“…This is in line with many studies that advocate that the dichotomisation between environmental selection and stochasticity is an inaccurate portrayal processes structuring real metacommunities (Gravel et al, 2006;Winegardner, Jones, Ng, Siqueira, & Cottenie, 2012). Environmental selection is an important process structuring aquatic insect metacommunities Siqueira, Bini, Roque, Couceiro, et al, 2012), including those in Atlantic Forest streams (Roque et al, 2010;Valente-Neto, Saito, Siqueira, & Fonseca-Gessner, 2016). In this process, species are filtered from patches in which environmental conditions are outside their niche breadth (Leibold et al, 2004;Vellend, 2010) (modelled in both the niche and nichestochastic scenarios).…”

Beetle mania: Understanding pond aquatic beetles diversity patterns through a multiple-facet approach

“…Aquatic Coleoptera is one of the most diverse orders of aquatic macroinvertebrates, exhibiting a wide morphological, functional, and ecological range; they are relatively easy to sample, and their taxonomy and biogeography are reasonably well-known [ 18 ]. Many studies have demonstrated that water beetles respond to variation across space and feature complex diversity patterns in freshwater ecosystems [ 1 , [19] , [20] , [21] , [22] , [23] , [24] , [25] ], but relationships within the four diversity attributes and their variation across wide spatial gradients have not been deeply studied.…”