流域库坝工程开发的生物多样性敏感度分区

流域生态敏感性是流域生态系统遇到干扰时产生生态失衡与生态环境问题的难易程度和可能性大小,生物多样性是其影响最为重要的生态因子。主要考虑物种丰富度、珍稀程度、濒危程度、保护等级和生态系统类型等生物多样性敏感因子,借助GIS强大的空间数据采集和建模分析能力,在专家打分求取敏感因子权重基础上,通过空间模型计算生物多样性敏感度综合得分。基于二级流域综合得分最大值,采用ARCGIS自然间断点法实现敏感度分区,结果表明:极敏感区域主要分布在长江区的岷沱江、金沙江石鼓以下、金沙江石鼓以上、宜宾至宜昌、嘉陵江流域,珠江区的郁江、红柳河和西江流域,西南诸河区的澜沧江、红河和怒江及伊洛瓦底江流域,黄河区的龙羊峡以上流域等,这些区域水生生物特有种和受威胁物种丰度大,国家级自然保护区密集,是陆地生物多样性最丰富的地区。不敏感区域主要分布在松花江区除第二松花江以外流域,西北诸河区的塔里木盆地荒漠、古尔班通古特荒漠、中亚西亚内陆河、塔里木河干流等荒漠区,松花江区低温高寒,具有大森林、大草原、大湿地、大农田和大水域的特点,库坝工程对其生物多样性产生影响的可能性较小,西北诸河的荒漠区生境严酷,生物多样性贫乏,也不具备修建大型水库的条件,生物多样性敏感度也较低。其它区域介于二者之间,因其所处的生态系统类型、物种丰富度、珍稀程度、濒危程度和保护等级不一样,生物多样性敏感度各异。对流域库坝工程产生的生物多样性敏感度进行辨识,可为未来流域水资源合理和适度开发提供科学依据。

Biodiversity sensitivity zoning of river dam and reservoir engineering development

Ecological sensitivity refers to the reflection degree of the ecosystem to human activities and natural environment's changes; it explains the accessibility and possibility of the effect of regional ecological environment. Watershed ecological sensitivity is the degree of difficulty and possibility of ecological imbalance and environmental problems when the ecosystem encountered interference. Biodiversity is the most important ecological factor that can be affected by the Watershed ecological sensitivity. By considering the main biodiversity sensitive factors such as ecosystem types, species richness, rarity, endangered and protected level, this paper identified the ecological effects possibility of watershed dam and reservoir projects. By means of GIS technology's powerful and spatial data acquisition, processing and modeling analysis capabilities, the biodiversity sensitivity index was calculated based on the weights of the expert's score. Sensitivity partition was achieved in accordance with the principle of ARCGIS natural breaks methodology based on the secondary basin area maximum integrated sensitivity index. The results show that the most sensitive areas are mainly located at Min Tuo Jiang, Jinsha river Shigu downstream, Jinsha river Shigu upstream, Yibin to Yichang and Jialing River of Yangtze River region; Yujiang, Hongliuhe and Xijiang of Pearl River region; Lancang River, Red River, Nujiang and Irrawaddy River of Southwestern rivers region; Longyangxia's upstream of Yellow River region. These areas which have rich kinds of endemic aquatic species, threatened species and intensive national nature reserve, are the most abundant biodiversity areas. Insensitive areas are mainly at Songhua river region except the second Songhua river area, Tarim basin desert, Gurbantunggut desert, central & western Asian inland river and Mainstream of the Tarim River in Northwestern rivers region. The characteristics of Songhua river region are low temperature, forestclimate steppe climate, wet, big farmland and waters climate, and the engineering reservoirs are less likely to affect biodiversity. The desert areas in the Northwestern rivers region have harsh ecological and poor biodiversity enviroment, also an insufficient condition of building a large reservoir with a low biodiversity sensitivity.The sensitivity of other areas is between the two areas that mentioned above, different sensitivity of biodiversity depends on its ecosystem types, species richness, rarity, endangered and protected level. The main area in Songhua river region is insensitive area, which occupies 91.92% of total area. Liaohe area is mainly less sensitive area and sensitive area, the percentages are 52.83% and 47.17% respectively. The main area of Yellow river region is sensitive area, and Longyangxia to Lanzhou is more sensitive area. The main area of Yangtze River region and Pearl River region is the most sensitive area, the proportion percentage is 50.47% and 50.46% respectively. The more sensitive area of southeastern rivers region is 70.70% of the whole area. The most sensitive area in Southwestrn rivers has 46.57% of the Southwestern rivers area, and the sensitive area in Southwestern rivers is 53.43%. Qinghai Lake river system of the Northwestern rivers region is more sensitive area, the oasis on the edge of the desert and the piedmont area is sensitive area. It can be used to provide a scientific prove of reasonable and suitable development for the river water resource in the future by recognizing the biodiversity's susceptibility causing by reservoir engineering.