Acta Oecologica 115 (2022) 103835 Available online 26 April 2022 1146-609X/© 2022 Elsevier Masson SAS. All rights reserved. Riverine barrier hypothesis explains the structure of dung beetle communities in Brazilian Coastal Sand-dune forests Letícia Vieira a, * , Cristiane Costa b , Fernando Z. Vaz-de-Mello c , Júlio Louzada b a Universidade Federal de Lavras, Departamento de Ciˆ encias Florestais, Laborat´ orio de Ecologia Florestal, Caixa, Postal 3037, CEP 37200-900, Lavras, MG, Brazil b Universidade Federal de Lavras, Departamento de Ecologia e Conservaç˜ ao, Laborat´ orio de Ecologia e Conservaç˜ ao de Invertebrados, Caixa, Postal 3037, CEP 37200- 900, Lavras, MG, Brazil c Universidade Federal de Mato Grosso, Instituto de Biociˆ encias, Departamento de Biologia e Zoologia, Av. Fernando Correa s/n, Boa Esperança, Cuiab´ a, MT, 78060- 900, Brazil A R T I C L E INFO Keywords: Biogeographic pattern Geographical flter Latitudinal gradient Restinga Scarabaeinae Spatial segregation ABSTRACT The Riverine Barrier Hypothesis (RBH) predicts that tropical rivers can be effective barriers to species dispersion, affecting different scales of biological organization, from genes to assemblages. We disentangled the latitudinal from the river presence effect to test the hypothesis that the Doce river mouth acted as a geographical, historical barrier for insects through North and South directions of the Brazilian coast, affecting the current community structure. We sampled dung beetle communities. In 16 Coastal Sand-dune Forest (“Restinga”) patches, across the Doce River Basin in the Brazilian coastline, nine through the South and seven through the North direction of the Doce River’s mouth. We analyzed the relationship between the community composition and richness relative to the river (North and South regions) and latitude using linear modeling over a distance matrix (DistLM) approach. The latitude explained 17.74% of the total variation in dung beetle species composition, and the regional position relative to Doce River’s mouth exhibited a signifcant effect (Pseudo F = 2.8479; p = 0.005) only after removing the latitudinal effect, here representing the habitat fltering. Both variables explained together with a total of 32.52% of the variability in dung beetles composition at coastal sand dune forests. The geographical position alone explained 48% of the richness difference between the North and South regions of the Doce River’s mouth (Pseudo F = 16.534; p < 0.01). Meanwhile, the latitudinal position of the sites exhibited no signifcant rela- tionship with species richness. Our fndings highlight the role of Doce River as a biogeographical flter in the Doce river basin, while it represents the primary determinant of geographical segregation of the two key-species central to the dung beetle community structure. 1. Introduction The concept of community assembly (Keddy, 1992) theorizes species fltering process acting primarily at geographical and ecological di- mensions (Weiher et al., 2011). The species’ geographical range depends mainly on dispersal capacity and temporal dimensions (Thuiller et al., 2013). Whereas the spatial and temporal patterns of biological com- munities are explained as a result of a fltering process imposed over a regional species pool, limiting species occurrence and distribution in the landscapes (Keddy, 1992). After that, niche flter selects species capable of maintaining viable populations under a particular abiotic context and are shaped by the intra- and interspecifc interactions (Chase and Lei- bold, 2003). Geographical constraints shape species range, limiting their dispersal and breeding, leading eventually to local extinction, lineage distinction, and even speciation (Brown, 2003). Tropical rivers can be effective barriers to the gene fux, as predicted by the Riverine Barrier Hypothesis (RBH) (Wallace, 1852). The RBH is grounded on the fact that species range distributions in the tropics often coincide with river boundaries (Voelker et al., 2013). However, the pieces of evidence supporting the RBH can be multiple, from gene to community-level (Costa, 2003; Cabanne et al., 2007; Naka et al., 2012; Voelker et al., 2013; Thom´ e et al., 2014; Kopuchian et al., 2020; Figueiredo-V´ azquez et al., 2021). In the last decades, empirical evidence supporting RBH highlighted the role of large Amazonian rivers limiting the species distribution range at a regional level and generating phylogeographical differentiation * Corresponding author. E-mail address: leticia.vieira@ufa.br (L. Vieira). Contents lists available at ScienceDirect Acta Oecologica journal homepage: www.elsevier.com/locate/actoec https://doi.org/10.1016/j.actao.2022.103835 Received 26 May 2021; Received in revised form 4 April 2022; Accepted 11 April 2022