Odonata responses to dispersal and niche processes differ across Amazonian endemism regions

Abstract

Niche and dispersal‐based processes govern freshwater communities, such as aquatic insects, shaping their distribution and establishment in the environment. So, we aimed to address the relative influence of niche and dispersal‐based processes on Odonata diversity in Amazonian freshwater systems, and the influence of species dispersal functional traits on their longitudinal and latitudinal ranges. We used the Dispersal‐Niche Continuum Index (DNCI) to test (i) regions more distant would present a prevalence of dispersal‐based processes, and (ii) different patterns would come from the two Odonata suborders; and by applying generalised linear models, we tested (iii) dispersal‐related functional traits from the suborders would influence latitudinal and longitudinal midpoints of the species. We found that more distant regions had lower values of pairwise Dispersal–Niche Continuum, mainly for Zygoptera, corroborating our first hypothesis. Moreover, Zygoptera also presented the lowest absolute values of Dispersal–Niche Continuum and Anisoptera presented a joint influence of niche and dispersal‐based processes, agreeing with our second hypothesis. Only Zygoptera presented a significant association between dispersal functional traits and longitudinal midpoints, corroborating our third hypothesis. Our results indicated a prevalence of dispersal‐related processes for Zygoptera, which can be explained by massive geographical barriers, such as the rivers, and their narrow physiological and ecological tolerance. Moreover, dispersal‐related traits demonstrated significant influence on longitudinal midpoints of Zygoptera, a scenario that the presence of the rivers may explain. A better understanding of the prevalent predictors of the species and how their dispersal ability governs their distribution has conservational implications.