Benthic macroinvertebrate communities in sites with native forest presence and absence in north Patagonia

ABSTRACT The benthic fauna in northern Patagonian streams is characterized by presence of water quality indicator species. The aim of the present study was characterized the benthic communities in streams associated to sites with presence of Nothofagus forests and with human intervention without Nothofagus forests using null models in ecology, unified neutral theory of biodiversity (UNTB) and unweighted pair group method with arithmetic mean (UPGMA). The results of species co-occurrence null model revealed that species associations are random, whereas the results of niche overlap null models revealed the presence of niche overlap. The UNTB results revealed low species number. The results of UPGMA revealed that species composition is specific for each site existing marked differences. The exposed results agree with results observed for central and northern Patagonian Chilean rivers, where the species composition is variable in according to surrounding basin properties and seasonal conditions.

摘要 巴塔哥尼亚北部溪流的底栖动物群落以存在水质指示物种为典型特征。本研究旨在采用生态学零模型、统一生物多样性中性理论（Unified Neutral Theory of Biodiversity, UNTB）以及算术平均非加权配对组法（Unweighted Pair Group Method with Arithmetic Mean, UPGMA），对分布有南山毛榉（Nothofagus）林的位点周边溪流，以及无南山毛榉（Nothofagus）林且受人类活动干扰的溪流中的底栖群落特征进行表征。物种共现零模型的分析结果显示，物种关联呈随机状态；而生态位重叠零模型结果则表明存在生态位重叠现象。统一生物多样性中性理论（UNTB）的分析结果显示物种丰富度较低。算术平均非加权配对组法（UPGMA）的分析结果表明，各采样位点的物种组成具有特异性，且存在显著差异。本研究结果与智利巴塔哥尼亚中部及北部河流的已有研究结果一致，即物种组成会随流域周边环境特征及季节条件发生变化。