Data of mollusk communities from intermittent rivers in Brazilian semiarid region

Studies on reservoirs in the Brazilian semiarid region identify that the most important factors for the community structuring of these animals are the hydroperiod and its related variables (precipitation, depth, and water temperature) (Almeida et al., 2018; Okumura & Rocha, 2020; Silva et al., 2020b). Therefore, these factors, as well as anthropic impacts, should also structure mollusk communities, in intermittent rivers. It is also assumed that seasonality similarly influences the community structure when analyzing intermittent rivers from the same hydrographic basin. In this sense, the objective of this study is to investigate the influence of determining factors for environmental heterogeneity, linked to the irregularity of hydroperiods and the state of conservation of intermittent rivers in the Brazilian semiarid region, on the structure and dynamics of limnic mollusk communities.
When analyzing the data, our results showed that the environmental heterogeneity, characteristic of semiarid regions and that is generated by the irregularity of the hydroperiods, does not contribute to a high species richness and that the communities of limnic mollusks of intermittent rivers in these regions are shaped by the association of environmental heterogeneity with alterations anthropic consequences resulting from the multiple uses of the margin and bed of the rivers. Additionally, the high abundance of M. tuberculata and B. straminea species in the analyzed rivers, influenced by the previously mentioned factors, reinforces attention to problems related to species invasion and the maintenance of the cycle of parasites of medical importance, respectively.
Our results also show that it is necessary to expand ecological studies in the semiarid region, since many aspects of the dynamics of mollusk communities, historically accepted as a standard, are singular in this region due to the dynamism and the extreme changes to which they are subject in short periods of time.