Hepp Luiz Ubiratan, Santos Sandro
Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões-Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS CEP 99700-000, Brazil.
Environ Monit Assess. 2009 Oct;157(1-4):305-18. doi: 10.1007/s10661-008-0536-7. Epub 2008 Oct 9.
Different land uses affect the characteristics of a hydrographic basin, reflected in the river water quality, and consequently affecting the aquatic biota. The benthic community closely reflects the alterations caused by different human activities. In this study, the effects of different land uses were evaluated by analysis of the benthic community structure in streams with urban, agricultural and pasturage influences, as well as areas in better-conserved regions. The abiotic parameters showed distinct seasonal variability, which did not occur with the benthic organisms. A degradation gradient was observed among the study sites, in the headwaters-agriculture-pasture-urban direction. By the CCA its possible to observe that the density of organisms tended to increase along this gradient, whereas richness, diversity, evenness, and EPT families decreased. The most intense effects of land use on the benthic community composition, richness, and diversity were observed in urban areas (F (1,4) = 16.0, p = 0.01; F (1,4) = 8.97, p = 0.04; respectively). In conclusion a trend in the benthic community is observed in to predict alterations caused for the different land uses, mainly, when the source point pollution, as the case of urban area.
不同的土地利用方式会影响水文流域的特征，这在河流水质中有所体现，进而影响水生生物群。底栖生物群落能密切反映不同人类活动所造成的变化。在本研究中，通过分析受城市、农业和畜牧影响的溪流以及保护较好地区的底栖生物群落结构，评估了不同土地利用方式的影响。非生物参数呈现出明显的季节性变化，而底栖生物则没有。在研究地点之间观察到了一个退化梯度，方向为源头 - 农业 - 畜牧 - 城市。通过典范对应分析（CCA）可以观察到，生物密度倾向于沿着这个梯度增加，而丰富度、多样性、均匀度和蜉蝣目、襀翅目和毛翅目昆虫（EPT）科的数量则减少。在城市地区观察到土地利用对底栖生物群落组成、丰富度和多样性的影响最为强烈（分别为F (1,4) = 16.0，p = 0.01；F (1,4) = 8.97，p = 0.04）。总之，观察到底栖生物群落存在一种趋势，即能够预测不同土地利用方式所造成的变化，主要是在存在源点污染的情况下，如城市地区。
