Machado Ng, Venticinque Em, Penha J
Laboratório de Biologia da Conservação – LABIC, Instituto Federal de Mato Grosso – IFMT, Campus Cuiabá Bela Vista, CEP 78050-560, Cuiabá, MT, Brazil.
Braz J Biol. 2011 Aug;71(3):577-86. doi: 10.1590/s1519-69842011000400002.
Over the last 30 years, the Cerrado has been experiencing various antropic impacts that have brought about alterations to species composition, structure and functioning of aquatic habitats. Therefore, studies on negative impacts are useful to prevent future damage and restore environmental quality. The objectives of our study were: i) to adapt an index of biotic integrity of streams in the Rio Cuiabá Basin and ii) to analyze if the Index of Biotic Integrity (IBI) correlated with the environmental quality measured by the Index of Environmental Quality (IEQ) and with the mesohabitat structure. We sampled 26 streams in sub-basins of the Cuiabá River. In each stream, we closed a stretch of 50 m with blockage nets and used electrofishing to capture fish. To obtain a measure of environmental quality in sampled units, we characterized the stream and its micro basin. For the analyses, we used the Spearman Correlation, Kruskal-Wallis test and Analysis of Multiple Regression. We collected 697 individuals distributed into 6 orders, 15 families and 49 species. The IBI followed changes on environmental quality measured by IEQ when we removed streams that present natural barriers from the analysis (r² = 0.4; r² = 0.58). Types of land use did not affect the biotic integrity (n = 26; df = 4; H = 4,860; p = 0.302), but natural and artificial barriers affected it (n = 26; df = 4; H = 11,027; p = 0.026). The IBI was not sensitive to variations in mesohabitat structure (F₂,₂₃ = 0.373; r² = 0.031; Axe 1 p = 0.620; Axe 2 p = 0.490). The IBI is certainly a reasonable instrument for evaluating changes in the environment, but we cannot ignore the fact that we were able to obtain the same result with any combinations of metrics. This makes its analysis and interpretation difficult.
在过去30年里，塞拉多地区一直受到各种人为影响，这些影响已导致水生栖息地的物种组成、结构和功能发生改变。因此，关于负面影响的研究有助于预防未来的破坏并恢复环境质量。我们研究的目的是：i）调整库亚巴河流域溪流的生物完整性指数；ii）分析生物完整性指数（IBI）是否与环境质量指数（IEQ）衡量的环境质量以及与中栖息地结构相关。我们在库亚巴河的子流域对26条溪流进行了采样。在每条溪流中，我们用阻塞网封闭一段50米的河段，并使用电鱼法捕获鱼类。为了获得采样单元中环境质量的度量，我们对溪流及其微流域进行了特征描述。在分析中，我们使用了斯皮尔曼相关性、克鲁斯卡尔 - 沃利斯检验和多元回归分析。我们收集了697个个体，分布在6个目、15个科和49个物种中。当我们从分析中去除存在自然屏障的溪流时，IBI随IEQ衡量的环境质量变化而变化（r² = 0.4；r² = 0.58）。土地利用类型并未影响生物完整性（n = 26；df = 4；H = 4,860；p = 0.302），但自然和人工屏障对其有影响（n = 26；df = 4；H = 11,027；p = 0.026）。IBI对中栖息地结构的变化不敏感（F₂,₂₃ = 0.373；r² = 0.031；轴1 p = 0.620；轴2 p = 0.490）。IBI无疑是评估环境变化的合理工具，但我们不能忽视这样一个事实，即我们用任何指标组合都能得到相同的结果。这使得对其进行分析和解释变得困难。
