挠力河流域河流的B-IBI评价

挠力河流域是中国东北三江平原地区重要的商品粮基地之一.选择挠力河流域干支流6个河段21个样点,2007年7月进行河流大型无脊椎动物样本的采集和鉴定,并分别采用3分法和比值法进行了河流大型无脊椎动物完整性指数(简称B-IBI)计算与评价.结果显示,使用两种方法得出的评价结果基本一致,且与水质、生境质量评价结果呈显著正相关关系.研究表明,挠力河流域河流生物完整性总体良好,个别样点较差.全流域属于无干扰和轻度干扰的样点占71.4%,中度干扰的样点占23.8%,重度干扰的仅占4.8%.得分较高的样点多处于挠力河支流或干流上游的山区,人类活动较少,河流周围为茂密的森林植被;分值较低的样点主要位于支流下游或干流中游,均临近居民点,水体质量较差,河岸人类活动密集,植被覆盖度低,土地开发利用强烈等特征.这表明,河流B-IBI受到河岸土地覆被和土地利用(LULC)的重要影响.

B-IBI assessment of streams in Naoli River Watershed,China

The Naoli River Watershed is one of the important grain production bases in the Sanjiang Plain, northeast China. After over 50 years of agricultural development, this region has not only tremendously contributed to China's grain production but has also accumulated great wealth to this region. However, environmental degradation trends in the region have been observed due to overemphasizing the pursuit of economic efficiency and ignoring natural environment protection. This paper assesses the biotic integrity in the Naoli River Watershed using the Index of Biotic Integrity of the Benthic Invertebrates (B-IBI). The aquatic benthic invertebrate data were collected in July 2007 from 21 sample sites both in the main stream and 3 tributaries. After identification of these benthic invertebrates in the laboratory, B-IBI index were calculated using both the three scoring method and the ratio scoring method. Both methods come with identical assessment results. Statistical analysis shows a significant positive correlation between the scores of the stream B-IBI and the assessment results of the water quality as well as the habitat quality. The overall score values of the B-IBI in this region are generally high with only a few individual sample sites scoring poorly. Among the 21 sample sites, 15 of them can be classified as in good condition without or with little human impact, covering 71.4% of the sample sites; 5 as in average condition with medium human impact, covering 23.8% of the sample sites; 1 as in poor condition with severe human impact, covering 4.8% of the sample sites. The study illustrated that the sample sites with high-scores are mostly located either in the tributaries or the upper reaches of the main stream in the mountainous areas, covered by dense forest with little human activities; the sample sites with low-scores are adjacent to human settlements and normally located in either the outlets of the tributaries or the middle reaches of the main stream with low riparian vegetation coverage, poor water quality, intensive human activities, and intensive land use. Therefore, it can be concluded that the land use and land cover (LULC) have had a significant impact on the stream B-IBI of the Naoli River.