Riverine barrier hypothesis explains the structure of dung beetle communities in Brazilian Coastal Sand-dune forests

• Published in: Acta oecologica (Montrouge) 2022-08, Vol.115, p.103835, Article 103835
• Main Authors: Vieira, Letícia, Costa, Cristiane, Vaz-de-Mello, Fernando Z., Louzada, Júlio
• Format: Article
• Language: English
• Subjects: Biogeographic pattern; Geographical filter; Latitudinal gradient; Restinga; Scarabaeinae; Spatial segregation
• ISSN: 1146-609X; 1873-6238
• DOI: 10.1016/j.actao.2022.103835

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 significant effect (Pseudo F = 2.8479; p = 0.005) only after removing the latitudinal effect, here representing the habitat filtering. 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