Hermes-Silva S, Zaniboni-Filho E
Universidade Federal de São Carlos, São Carlos, SP, Brazil.
Braz J Biol. 2012 Aug;72(3):489-95. doi: 10.1590/s1519-69842012000300011.
To evaluate the effects of macrophytes presence in the structure of littoral fish assemblages in the littoral zone, monthly samples were collected from September, 2006 to August, 2007 in an impounded tributary of the Itá Reservoir, the Fragosos River, located in the Upper Uruguay River Basin. Fish were collected using a beach seine and sampling was conducted in the littoral zone inside a macrophyte stand and in an area with no macrophytes. A total of 5,191 fish were captured during the study period. Fish assemblage attributes (fish abundance, species richness, and diversity) varied significantly between sampling months and areas. The abundance of Astyanax cf. bimaculatus, Astyanax fasciatus, Geophagus brasiliensis, and Gymnotus carapo also varied significantly between sampling months and areas. Detrended Correspondence Analysis showed a clear spatial segregation at the first axis and a slight temporal segregation at the second axis. These results were confirmed by Multiple Response Permutation Procedure analysis. Apparently, the presence of the aquatic macrophytes is not the only factor influencing the distribution of littoral fish assemblages in the Fragosos River. Littoral fish seem to be taking advantage of low- to medium-sized macrophyte stands, but few species used maximum-sized stands.
为评估大型植物的存在对乌拉圭河上游流域伊塔水库一条蓄水支流弗拉戈索斯河中沿岸带鱼类群落结构的影响，于2006年9月至2007年8月每月进行采样。使用海滩围网收集鱼类，采样在大型植物群落内的沿岸带和无大型植物的区域进行。研究期间共捕获5191条鱼。鱼类群落属性（鱼类丰度、物种丰富度和多样性）在采样月份和区域之间存在显著差异。双线脂鲤属近双斑双线脂鲤、条纹脂鲤、巴西丽体鱼和裸背电鳗的丰度在采样月份和区域之间也存在显著差异。去趋势对应分析显示，第一轴上有明显的空间隔离，第二轴上有轻微的时间隔离。这些结果通过多重响应置换程序分析得到证实。显然，水生大型植物的存在并非影响弗拉戈索斯河沿岸带鱼类群落分布的唯一因素。沿岸带鱼类似乎在利用中小型大型植物群落，但很少有物种利用最大型的群落。
