Maltchik L, Stenert C, Kotzian C B, Pereira D
Laboratório de Ecologia e Conservação de Ecossistemas Aquáticos, Universidade do Vale do Rio dos Sinos, São Leopoldo, RS, Brazil.
Braz J Biol. 2010 Aug;70(3):473-82. doi: 10.1590/s1519-69842010005000003. Epub 2010 Mar 19.
Freshwater molluscs play an important role in aquatic ecosystems, providing food for many fish species and vertebrates. Investigations on factors that determine mollusc species richness and distribution in wetland systems are scarce in the Neotropical region. The main goal of this study was to determine how much variation in mollusc richness and composition is explained by area, hydroperiod, altitude, water conductivity, and dominant aquatic vegetation. This survey was performed in an extensive area of a Neotropical region (approximately 280,000 km(2) in southern Brazil), with a large number of wetland systems (111) and covering a wide gradient of altitude and wetland surface area. The mollusc richness was positively associated with wetland area and negatively associated with altitude. The richness and composition of the freshwater molluscs were similar between permanent and intermittent wetlands and it did not differ significantly between aquatic bed and emergent wetlands. The first three axes of CCA explained 16.2% of the total variation in the composition of the freshwater mollusc observed. The variation in the composition had a correlation with wetland area, altitude and water conductivity. Our results showed that the wetlands are important habitats for molluscs in southern Brazil, and that the richness and the composition of molluscs were associated with area, altitude, water conductivity and dominant vegetation.
淡水软体动物在水生生态系统中发挥着重要作用，为许多鱼类和脊椎动物提供食物。在新热带地区，关于决定湿地系统中软体动物物种丰富度和分布的因素的研究很少。本研究的主要目标是确定面积、水文周期、海拔、水电导率和优势水生植被对软体动物丰富度和组成的变化有多大解释力。这项调查在新热带地区的一个广阔区域（巴西南部约280,000平方公里）进行，有大量湿地系统（111个），涵盖了广泛的海拔和湿地表面积梯度。软体动物丰富度与湿地面积呈正相关，与海拔呈负相关。永久性和间歇性湿地之间淡水软体动物的丰富度和组成相似，水生床和挺水湿地之间也没有显著差异。典范对应分析（CCA）的前三个轴解释了观察到的淡水软体动物组成总变异的16.2%。组成的变异与湿地面积、海拔和水电导率相关。我们的结果表明，湿地是巴西南部软体动物的重要栖息地，软体动物的丰富度和组成与面积、海拔、水电导率和优势植被有关。
