鄂西北珍稀濒危植物及物种多样性空间尺度分析

为了探究鄂西北地区珍稀濒危植物及其多样性空间分布与该区域地理环境的关系，于2007-2017年先后对鄂西北8个自然保护区的植物资源进行了调查，对其种类组成、地理成分、生活型及物种多样性的空间分布特征进行研究。结果显示：（1）鄂西北珍稀濒危植物共有262种，隶属于62科149属；（2）该区域珍稀濒危植物地理成分与生活型谱具有地域过渡性和多样性；（3）鄂西北地区珍稀濒危植物的物种丰富度峰值出现在海拔900~1700 m区段，物种丰富度与海拔区段间具有显著的二次方程关系：y=-0.5107x²-12.43x+7.3111（R²=0.7867，P=0.04）；（4）不同空间尺度下，物种Shannon-Wiener多样性指数（H_D）、均匀度指数（E_D）、Margalef多样性指数（K_D）随空间尺度的变化均呈幂函数关系，其相关系数分别为R²=0.7303（H_D）、R²=0.8858（E_D）、R²=0.9805（K_D）。研究表明H_D、E_D、K_D值的变化幅度可能与该区域地理环境的变化有关。目前砍伐毁林和过度采挖是该地区珍稀濒危植物最大的威胁因素，建议从珍稀濒危植物物种多样性分布与地理环境特性相结合的角度加强管理，为区域珍稀濒危植物的科学恢复提供支撑。

Spatial scale analysis of the species diversity and distribution of rare and endangered plants in northwest Hubei,China

To explore the relationship between the spatial distribution of rare and endangered plants and their diversity and geographical environment, we investigated eight nature reserves in northwest Hubei, China, from 2007 to 2017. Results showed that:(1) There were 262 species of rare and endangered plants in northwest Hubei, belonging to 62 families and 149 genera. (2) The geographical composition and life-form spectra of the rare and endangered plants in the region were transitional and diverse. (3) Peak species richness of these plants occurred in the 900-1700 m range, and there was a significant quadratic relationship between species richness and altitude:y=-0.5107x²-12.43x + 7.3111 (R²=0.7867, P=0.04). (4) Analysis of species diversity under different spatial scales indicated that the Shannon-Wiener index (H_D), Evenness index (E_D), and Margalef index (K_D) all showed significant correlations with spatial scale. The correlation coefficients were R²=0.7303 (H_D), R²=0.8858 (E_D), and R²=0.9805 (K_D), respectively. Results also showed that correlations existed in the magnitude of changes in H_D, E_D, and K_D and changes in the geographical environment. At present, deforestation and over-exploitation are the greatest threats for the rare and endangered plants in the region. It is recommended that management and conservation need to be strengthened from the perspective of species diversity and geographical environment characteristics to provide support for the scientific restoration of rare and endangered plants in the region.