Diversidade de anfíbios anuros em áreas úmidas palustres de uma bacia hidrográfica do Sul do Brasil

Abstract

The wetlands are recognized internationally as priority ecosystems for the conservation, because they present great importance in the survival in countless life ways, besides countless functions and values for the humanity. It’s considered that 50% of wetlands originals of Earth were already degraded. In that sense, the selection of priority wetlands for the conservation is a great challenge, being necessary risings of the biodiversity in order to subsidize handling programs and conservation of these ecosystems. The small wetlands are also particularly important habitats for herpetofauna due to the narrow dependence of those organisms with the aquatic atmospheres during the several life phases. The importance of the small wetlands for the community of amphibians has been a little studied in the south of Brazil. That gap in the knowledge is still more preoccupying, because, region of the Rio Grande do Sul presents of 15% of the total fauna of amphibians of the country with larger diversity of amphibians of the world. Objectives of this study were (1) to know the diversity of amphibians anuran in eight small wetlands of the south of Brazil, (2) to compare the variation of the wealth, abundance and anuran composition among two types of wetlands (with and without sheet of superficial water), (3) to analyze the influence of the size of the wetlands, temperature of the air, relative humidity, precipitation in assemblages amphibians anuran and (4) to offer information for programs of conservation of wetlands of the south of Brazil. A total of eight wetlands was sampled quarterly among March of 2006 and February of 2007 in the hydrographic basin of Stream Santa Bárbara, Municipal district of Pelotas. They were identified 16 species of amphibians anuran distributed in six families. The family Hylidae was the most representative (43,75%). The medium wealth (F4,24=78,230; P <0,001) and abundance (F4,24=46,719; P <0,001) of anuran it varied in the time in the analyzed wetlands. The wealth and the anuran abundance were larger in the permanent wetlands (F1,6=122,223; P <0,001 ; F1,6=32,421; P <0,001 , respectively) that in the wetlands without sheets of water. The wealth and the total abundance of anuran were not influenced by the accumulated precipitation, relative humidity and temperature of the air (R2 =0,942, F3,1=5,407 P=0,304 and R2 =0,991, F3,1=38,721 P=0,117, respectively). The wealth and the anuran abundance were not influenced by the size of the wetlands (R2 =0,222; F1,6=1,717; P=0,238; R 2 =0,378; F1,6=3,648; P=0,105, respectively). This study presented important ecological information on the anuran community, proportionate relevant information for programs of conservation of the biodiversity of the south of Brazil.