青藏高原维管植物物种丰富度分布的情景模拟

Scenarios simulation of vascular plant species abundance distribution on Qinghai-Tibet Plateau

如何充分利用离散的观测数据,通过对维管植物物种分布丰富度及其与生境因子之间的相互作用和影响机理的定量分析,实现维管植物物种丰富度的空间分布及其情景模拟,是目前生物多样性研究前沿和核心内容之一。针对这一问题,在实现青藏高原37个国家自然保护区的维管植物物种数量收集和边界数据矢量化的基础上,分别进行维管植物物种数量与土地覆盖类型、环境因子和景观生态指数等三大类生境因子之间的相关关系的定量计算和对比分析,筛选和确定最佳相关分析方程,进而构建青藏高原维管植物物种丰富度的空间模拟分析模型。该模型中,维管植物物种丰富度与生境因子之间的复相关系数为0.94,模型验证结果表明,青藏高原的维管植物物种的平均丰富度为496.79种/100 km^2,其空间分布格局整体上呈东南向西北逐渐减少趋势;另外,除柴达木盆地荒漠区域以外,维管植物物种的空间分布随海拔的升高而减少。基于CMIP5 RCP 2.6、RCP 4.5和RCP 8.5三种气候情景模拟获得的青藏高原维管植物物种丰富度未来情景结果显示,在T0-T4(2010-2100)时段内,青藏高原维管植物物种丰富度整体将呈减少趋势。RCP 8.5情景下青藏高原维管植物物种丰富度的变化幅度最大,而RCP 2.6情景下的维管植物物种丰富度的变化幅度最小。研究表明,本文构建的模型能够对青藏高原维管植物物种丰富度的空间分布格局及其未来情景进行模拟分析,模拟结果可为青藏高原生物多样性及其对气候变化响应的综合评估和情景模拟提供方法和技术支持。

For quantitatively explaining the relationship between the vascular plant abundance and habitat factors in the Qinghai-Tibet Plateau, a spatial simulation method has been developed to simulate the distribution of vascular plant species abundance. In this paper, seven datasets covering 37 national nature reserves were used to screen the best correlation equation between the vascular plant abundance and habitat factors in the plateau. These datasets include imformation on the vascular plant type, land cover, mean annual biotemperature, average total annual precipitation, topographic relief, patch connectivity and ecological diversity index. The results show that the multiple correlation coefficient between vascular plant abundance and various of habitat factors is 0.94, the mean error validated with the vascular plant species data of 37 national nature reserves is 2.21 types/km^2, and the distribution of vascular plant species abundance gradually decreases from southeast to northwest, and reduces with increasing altitude except for the desert area of Qaidam Basin on the Qinghai-Tibet Plateau. Furthermore,the changes of vascular plant species abundance in the plateau during the periods from 1981 to 2010（T0）, from 2011-2040（T2）, from 2041 to 2070（T3） and from 2071 to 2100（T4） were simulated by combining the land cover change in China and the climatic scenarios of CMIP5 RCP2.6, RCP4.5 and RCP8.5. The results from T0 to T4 show that the vascular plant species abundance in the plateau would decrease in the future, the vascular plant species abundance had the biggest change ranges under RCP8.5 scenario and the smallest change ranges under RCP2.6 scenario. In short, dynamic change and interaction of habitat factors directly affect the spatial distribution of vascular plant species abundance on the Qinghai-Tibet Plateau.