Potential ecological distribution of alien mollusk Corbicula largillierti and its relationship with human disturbance in a semi-arid reservoir

Abstract

The introduction of exotic mollusk species has resulted in loss of biodiversity in semi-arid neotropical aquatic ecosystems. This study aims to relate the presence and density of Corbicula largillierti species to human disturbance, providing data for the conservation and management of aquatic ecosystems. Specimens were collected at Epita´cio Pessoa reservoir in December 2011 and June 2012, presenting densities of 20.96 and 62.89 individuals per square meter, respectively. Anthropic disturbance metrics were calculated considering the presence, type and intensity of disturbance in littoral, riparian and flood zones. The occurrence of C. largillierti was mainly associated to the variables total phosphorus (261.05 ± 342.22 mg/L) and total nitrogen (440.79 ± 103.77 mg/L), near to tributaries. The occurrence of exotic mollusk species is evidence of the need for freshwater ecosystem conservation and management, particularly in reservoirs used for water supply.

A introduc¸a˜o de espe´cies exo´ ticas de moluscos resulta em perda de biodiversidade em ecossistemas aqua´ ticos semia´ ridos neotropicais. Este estudo tem o objetivo de relacionar a presenc¸a e densidade da espe´cie Corbicula largillierti ao distu´ rbio humano, fornecendo dados para a conservac¸a˜o e manejo de ecossistemas aqua´ ticos. Os espe´cimes foram coletados no reservato´ rio Epita´cio Pessoa em dezembro de 2011 e junho de 2012, com densidades de 20,96 e 62,89 indivı´duos por metro quadrado, respectivamente. Me´tricas de perturbac¸a˜o antro´pica foram calculadas considerando a presenc¸a, tipo e intensidade de perturbac¸a˜o nas zonas litoraˆnea, ribeirinha e de inundac¸a˜o. A ocorreˆncia de C. largillerti esteve associada a`s varia´veis fo´ sforo total (261,05 ± 342,22 mg/L) e nitrogeˆnio total (440,79 ± 103,77 mg/L), em locais pro´ximos aos afluentes. A ocorreˆncia de espe´cies exo´ ticas de moluscos evidencia a necessidade de conservac¸a˜o e manejo de ecossistemas de a´gua doce, principalmente em reservato´ rios utilizados para abastecimento de a´gua.