Diversidade e dinâmica de comunidades de esponjas (porifera, demospongiae) em sistemas de arroz irrigado na planície costeira do Rio Grande do Sul

Abstract

Wetlands are important ecosystems for conservation, due to the rich biodiversiy they support. In Southern Brazil (Rio Grande do Sul state), irrigated rice cultivation is one of the main threats for wetlands. However, many authors have considered rice fields as man-managed ecosystems, and that they can contribute for biodiversity conservation. Freshwater sponges are important components of the biological communities in Rio Grande do Sul coastal wetlands. The main goal of this survey was to study the dynamics of Porifera assemblages in rice fields and irrigation canals at Rio Grande do Sul Coastal Plain along an annual cycle. Six rice fields and four irrigation canals were surveyed for gemmules on their sediments, on six sampling moments, representative of the four mains phases of a rice cultivation cycle. The species Heteromeyenia insignis, Corvoheteromeyenia australis, Ephydatia facunda, Heteromeyenia cristalina, Trochospongilla paulula, Radiospongilla amazonensis and Racekiela sheilae were detected. Six spec