基于优势种的生物多样性保护价值空间异质性研究——以长白山生态功能区为例

Spatial heterogeneity of biodiversity value based on dominant species: Changbaishan Ecological Function Zone as a case study

生物多样性保护是生态系统的主导功能之一,对生物多样性空间异质性的研究有助于准确认识区域的保护价值及重要性,但目前可借鉴的生物多样性价值空间异质性评价方法和经验偏少。以长白山生态功能区核心区为研究区域,基于生物多样性丰富区域优势物种的分布及其环境因子,通过Maxent评估生物多样性保护价值,将研究区域分为生物多样性保护高价值区、中价值区和一般价值区,并开展景观分析与评估。研究结果表明:研究区域内生物多样性保护高价值区域占总面积的42.9%、主要分布于长白山保护区内,保护区内的高价值斑块也较保护区外完整、面积大;研究区域内生物多样性高价值斑块的平均面积和最大斑块面积远高于中价值区和一般价值区,其斑块景观较完整、破碎化水平相对较低,是研究区域生物多样性保护价值和生态系统稳定性的重要基础。植被是对研究区域生物多样性影响最大的环境因子,其次是土层厚度和海拔。从生态系统完整性和过程连续性保护的需要,保护区南部缓冲区可考虑调整为核心区,保护区外还有较大面积的生物多样性高价值和中价值区域也应纳入保护区进行保护;长白山西坡是生物多样性高价值斑块最破碎的区域,应在未来的保护工作中予以特别关注。本研究表明关联优势种空间分布及环境因子是认识生物多样性价值及空间异质性的有效手段,本研究方法可为生态红线划定和国家公园设计提供参考。

Understanding spatial heterogeneity, which is a dominant function in ecosystem biodiversity, can help to highlight the conservation value and importance of a given area. However, there are limited available methods to assess the spatial heterogeneity of biodiversity value. We chose the kernel area of the Changbaishan Ecological Function Zone as the study site and constructed an assessment model of biodiversity value based on the dominant species in an area with high species richness and environmental variables, by using Maxent. Based on the aggregation of the dominant species and results of the biodiversity assessment, we partitioned the study area as into three areas of high, medium, and normal biodiversity values. Our study showed that the area with a high biodiversity value occupied 42.9% of the total study area and was mainly located within the Changbaishan Reserve; and the areas with high and normal biodiversity values comprised the main range of the Changbaishan Reserve. The mean and largest patch sizes of high biodiversity value were much larger than those of the medium and normal biodiversity values, reflecting the integrity and low fragmentation level in the landscape pattern, suggesting the competent function and robust stability of ecosystem and biodiversity values in our study. Together, the patches of high biodiversity value in the reserve were also larger and more integrated than those outside the reserve, and the order of the mean size with sub-function areas of the reserve was as follows：kernel area 〉 buffer area 〉 experimental area. Among the environmental factors, vegetation was the most important for the biodiversity value, followed by the soil depth and elevation in the study area. Based on the needs of protecting the ecosystem integrity and eco-process connectivity, the south buffer zone of the reserve should be incorporated into kernel areas; the large area with high and medium biodiversity values should be managed for more efficient conservation; and western Changbaishan Mountain was the most fragmented area with high diversity values and should be the focus of future conservation and management efforts. Our study also indicated that this method was effective to examine the spatial heterogeneity of biodiversity by associating the presence of dominant species with environmental variables and could be applied to biodiversity studies in other ecological function areas to delineate ecological conservation redlines and effectively design national parks.