Structure and dynamics of mollusk communities from intermittent rivers in Brazilian semiarid region

Abstract

Research conducted in intermittent rivers located in semiarid regions has revealed that the hydroperiod significantly affects the composition and dynamics of limnic communities. In our study, we examined the impact of key factors associated with abiotic heterogeneity resulting from irregular hydroperiods and the conservation status of two intermittent rivers in the semiarid region of Brazil on the structure and dynamics of limnic mollusk communities. For this, we collected material monthly throughout two years on the Itaim and Guaribas rivers, in Piauí semiarid region. We employed Two-Way Analysis of Variance (ANOVA) and PERMANOVA to assess variations in community structure based on mollusk species richness and abundance across the different rivers and seasons. Additionally, we employed Redundancy Analysis (RDA) to examine the influence of explanatory variables on community structure. Our findings demonstrate that in intermittent rivers within the Brazilian semiarid region, multiple factors contribute to the shaping of limnic communities, with anthropogenic disturbances playing a predominant role, challenging previous studies that have primarily emphasized the influence of hydroperiod on such communities.