汶川地震灾区生物多样性热点地区分析

汶川地震灾区位于长江上游,是我国大熊猫(Ailuropoda melanoleuca)的主要分布区,被保护国际认定的25个全球生物多样性热点地区之一.2008年5月12日发生的汶川大地震导致该区域生态环境遭受严重破坏,需要识别生物多样性热点地区,指导灾后生物多样性保护.选取物种生境质量、植被景观多样性指数和物种多样性指数作为评价指标,其中生境质量采用InVEST生物多样性模型计算,然后利用空间相关分析中G系数进行热点地区分析,探测出灾区生物多样性的热点区,并在此基础上与现有保护区分布、物种生境分布以及Marxan模型计算出的优先区进行对比验证.结果显示:热点区范围涉及到现有76％的保护区,且保护区内的热点区面积达到灾区所有保护区面积的55％；在选取的69个指示物种中有60个物种位于热点区的生境面积占这些物种在灾区的总生境面积的50％以上,有32个物种在80％左右,热点区内的所有指示物种生境总面积占整个灾区指示物种生境总面积的70％以上.基于空间相关分析方法得出的热点地区基本上与Marxan模型输出的优先保护区范围结果基本一致.但空间相关分析的热点区划分克服了Marxan模型优先保护区分布过于离散,孤岛效应明显的不足.

Identification of hotspots for biodiversity conservation in the Wenchuan earthquake-hit area

The Wenchuan earthquake-hit area is located in the Upper Yangtze River, which is the main distribution area of Giant panda (Ailuropoda melanoleuca) in China,and is one of the twenty-five hotspots for biodiversity conservation throughout the world defined by Conservation International, providing some important ecological service functions such as biological diversity conservation, water conservation, soil conservation and so on. Meanwhile, it plays an important role in ensuring regional ecological security. However, the eco-environment suffered from severe destruction in the Wenchuan 5.12 earthquake. In order to protect biological diversity in the Wenchuan earthquake-hit area, it is necessary for us to identify the hotspots for biodiversity conservation, which is of vital realistic significance for the government to devote efforts to reconstruction and is beneficial to optimum resource allocation. Firstly, we calculated the integrated biodiversity index and analyzed the spatial distribution of biodiversity,and then applied the index to determine the biodiversity hotspots by spatial analysis.The hotspots established by the spatial correlation method generally are consistent with the conservation priority area based on the Marxan model. The hotspots account for 76% of the existing nature reserve and the hotspots in Nature Reserve account for 55% of all existing Nature Reserves in the Wenchuan earthquake-hit area, and the total habitat area of all indicator species in the hotspots accounts for about 70% of the whole earthquake-hit area. The verification showed that the spatial correlation method is a reasonable method which can be applied to establishing hotspots. Furthermore, we also found that the spatial correlation analysis method of identifying hotspots is able to overcome the deficiency that the priority area based on the Marxan model is too discrete and islanding. Moreover, the results also showed that there are two biodiversity hotspots, i.e., the Minshan region and southern Qionglai mountain region. Maoxian Country lies at the junction of the two hotspots in the Wenchuan earthquake-hit area, so it is recommended to set aside a certain natural area as an ecological corridor between these two biodiversity hotspots. The biodiversity hotspots identified by the spatial correlation method can provide the decision-making basis for biodiversity conservation and depressing the influence on biodiversity in the processes of restoration and reconstruction in the Wenchuan earthquake-hit area.