衡水湖湿地恢复预案空间模拟及生态风险评价

基于湿地水位、坡度和土地利用/植被覆盖数据3个湿地生境要素,依据湿地生境自然生态单元要素组合和不同湿地恢复策略,在综合考虑水禽生境适宜性和保护区发展现状及未来目标的基础上,对衡水湖国家级自然保护区湿地的生态恢复进行了多预案设计.同时,将目标保护物种纳入考虑范围,通过对湿地恢复预案的生态指数、脆弱度和生态风险值进行评估,构建了一套相对系统的湿地恢复规划与评价体系,并通过对湿地恢复预案实施前后基础设施建设和人为活动导致的生态风险进行评估,揭示了各预案下湿地生态风险在保护区内的空间分布特征.研究表明,以湿地恢复为主的预案1的高风险值区域分布范围最大,以生境改造为主的预案2的高风险值区域分布范围在3个调整方案中最小,湿地恢复与生境改造并重的方案3的高风险值区域在3个调整方案中处于中等水平.结合鸟类适宜生境及其风险分布情况,湿地恢复和生境改造并重的方案值得推荐.

Modeling the scenarios of restoring the wetland in Hengshui Lake National Nature Reserve and assessing their ecological risk

Hengshui Lake National Nature Reserve is one of most ecologically valuable freshwater wetlands in the northern plain of China, providing crucial staging and wintering habitats for a large variety of endangered waterbirds. However, this unique wetland has suffered from serious habitat fragmentation and ecological function degradation due to increased socioeconomic activities within and surrounding the nature reserve. Aiming at enhancing its ecological function while balancing the needs between the conservation priorities and indispensable socioeconomic activities, three land use scenarios of wetland restoration were developed based on different magnitudes of wetland restoration, then we spatially modeled the scenarios of wetland restoration and evaluated their ecological risk. In this study, firstly, an ecotope was used as the planning unit, defined as a combination of landuse/landcover types and topographic factors (i.e., water level, slope) with RS & GIS techniques. Secondly, a systematic framework for ecological risk assessment was developed, in which Biodiversity Index, Ecological Vulnerability Index and Ecological Risk Index were introduced and employed. Finally, the pros and cons of the scenarios were evaluated based on its applicability. The results of modeling and assessments provide a basis for adopting measures of wetland restoration and consequent land use adjustment, and quantifying the regional ecological risk distribution for each scenario with spatial detail. Practical suggestions for the wetland restoration and habitat modification are thus forwarded. The results indicate paying equal attention to the site measures of wetland restoration and habitat alteration is best.