Oliveira V C, Gonçalves E A, Alves R G
Laboratório de Invertebrados Bentônicos, Departamento de Zoologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora ? UFJF, Rua José Lourenço Kelmer, s/n, Campus Universitário, São Pedro, Juiz de Fora, MG, Brasil.
Braz J Biol. 2014 May;74(2):267-73. doi: 10.1590/1519-6984.10512.
Riparian vegetation along streams in the Atlantic Forest in Brazil contributes to the formation of a highly heterogeneous leaf litter in streambeds. To investigate the structure and composition of the aquatic invertebrate community during the process of leaf decomposition of two plant species present along the banks of the stream studied, 21 plastic mesh bags containing 2.5g (dry weight) of leaf matter from each species (Alchornea glandulosa (Vell) and Cabralea canjerana End. and Poeppig), for a total of 5.0g, were placed in the streambed. Three bags were removed after 3, 6, 9, 12, 24, 48 and 96 days. The taxonomic density was negatively correlated with the remaining weight. The high density of collector organisms, such as Chironomidae, Oligochaeta and Amphipoda, on the last day of incubation, probably occurred due to the increased amount of fine organic matter in the more advanced decomposition stages. The highest α diversity (Shannon-Wiener) values were observed for the 3rd and 96th days of the experiment, while the β diversity values showed that these days presented the highest variation in the taxonomic composition, thus presenting a different faunistic composition. This study showed that the trophic structure and composition of aquatic invertebrates changes during the decomposition of leaf litter. The faunistic abundance and diversity observed in this study indicate that the entrance of material from plants growing along streams provides favorable conditions for the colonisation and establishment of invertebrates in lower-order streams, and thus points to the need to preserve riparian vegetation.
巴西大西洋森林溪流沿岸的河岸植被有助于在河床中形成高度异质的落叶层。为了研究在所研究溪流岸边生长的两种植物叶片分解过程中水生无脊椎动物群落的结构和组成，将21个塑料网袋放入河床中，每个网袋装有2.5克（干重）来自每种植物（腺苞木（Vell）和卡布拉雷亚番樱桃（End. and Poeppig））的叶片物质，总共5.0克。在3、6、9、12、24、48和96天后取出三个袋子。分类密度与剩余重量呈负相关。在孵化的最后一天，收集者生物（如摇蚊科、寡毛纲和端足目）的高密度可能是由于在更高级的分解阶段细有机物质数量增加所致。在实验的第3天和第96天观察到最高的α多样性（香农-维纳）值，而β多样性值表明这两天在分类组成上呈现出最高的变化，从而呈现出不同的动物区系组成。这项研究表明，在落叶层分解过程中，水生无脊椎动物的营养结构和组成会发生变化。本研究中观察到的动物区系丰度和多样性表明，来自溪流沿岸生长植物的物质进入为低阶溪流中无脊椎动物的定殖和建立提供了有利条件，因此指出了保护河岸植被的必要性。
