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.