Suriani-Affonso A L, França R S, Marchese M, Rocha O
Programa de Pós-graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos, São Carlos, SP, Brazil, 1356-905.
Braz J Biol. 2011 May;71(2):437-46. doi: 10.1590/s1519-69842011000300013.
The Oligochaeta forms an important part of the macroinvertebrates inhabiting sediments of lotic ecosystems. It has an important role in the cycling of matter and energy transfer in these environments. The aim of this study is to analyse limnological variables, their influence on the structure and diversity of benthic oligochaete taxocenosis in a stretch of the Upper São Francisco River and its tributary the Piumhi River. Samples were taken in two climatic periods, the dry season in October 2006 and 2007 and the rainy season in March 2007 and 2008 at three points along the Piumhi River and six points along the São Francisco River. The sediment of the São Francisco consisted predominantly of sand and clay, whereas the sediment of the Piumhi was mainly sandy. Six species of oligochaete occurred in the Piumhi River while seven were found in the São Francisco. Of these, Pristina synclites Stephenson, 1925, Pristina americana Cernosvitov, 1937, Bothrioneurum sp. Stolc, 1888 and Limnodrilus hoffmeisteri Claparede, 1862 occurred in the sediment of both rivers. L. hoffmeisteri showed the highest numerical abundance in the Piumhi River and Brinkhurstia americana (Brinkhurst, 1964) and L. neotropicus Cernosvitov, 1939 were the most abundant species in the São Francisco River. The highest oligochaete density was recorded in the Piumhi during the dry seasons. Canonical correspondence analyses (CCA) of sediment characteristics explained most of the data variability and the association of the presence of oligochaete species in the Piumhi and São Francisco Rivers with the limnological variables (grain size composition and total nitrogen and phosphorus concentrations in the sediment).
寡毛纲动物是栖息在流水生态系统沉积物中的大型无脊椎动物的重要组成部分。它在这些环境中的物质循环和能量转移中起着重要作用。本研究的目的是分析湖泊学变量，及其对圣弗朗西斯科河上游及其支流皮乌米河一段区域底栖寡毛纲动物分类群落结构和多样性的影响。样本采集于两个气候时期，即2006年10月和2007年的旱季以及2007年3月和2008年的雨季，在皮乌米河沿线三个点和圣弗朗西斯科河沿线六个点进行采集。圣弗朗西斯科河的沉积物主要由沙子和黏土组成，而皮乌米河的沉积物主要是沙质的。皮乌米河中有六种寡毛纲动物，而圣弗朗西斯科河中发现了七种。其中，1925年的斯蒂芬森普氏寡毛蚓、1937年的美洲普氏寡毛蚓、1888年的斯托尔克双神经寡毛蚓属和1862年的霍夫迈斯特颤蚓出现在两条河的沉积物中。霍夫迈斯特颤蚓在皮乌米河中数量最多，而1964年的美洲布林克赫斯特寡毛蚓和1939年的新热带颤蚓是圣弗朗西斯科河中数量最多的物种。旱季期间皮乌米河的寡毛纲动物密度最高。沉积物特征的典范对应分析（CCA）解释了大部分数据变异性，以及皮乌米河和圣弗朗西斯科河中寡毛纲动物物种的存在与湖泊学变量（沉积物的粒度组成以及总氮和总磷浓度）之间的关联。
