Abstract: The carrying capacity of resources and environment is important basis for sustainable development. Effective evaluation of carrying capacity of resources and environment is of great significance to the construction of ecological civilization society. Based on catastrophe progression method in catastrophe theory, we used 14 evaluation indices from four aspects of economy, society, resources and environment to evaluate the carrying capacity of urban comprehensive resources and environment of 21 prefecturelevel cities in Guangdong Province from 2000 to 2015. The results showed that in the 15 years, the index of comprehensive resources and environmental carrying capacity of Guangdong Province slightly decreased on the whole. Guangdong gradually changed from a high bearingcapacity province in most areas to a relatively high comprehensive bearing capacity index in the Pearl River Delta region and relatively weak comprehensive bearing capacity in Dongguan and Shenzhen. Each subsystem had different influence on the comprehensive carrying capacity of the city. The composite system of resources and environment is the supporting foundation of carrying capacity, while the composite system of economy and society is the powerful guarantee of carrying capacity. Among all cities, Jiangmen, Shantou, Huizhou and Foshan had the highest comprehensive carrying capacity index of resources and environment, indicating that the more balanced the economic level and resources and environment, the higher the comprehensive carrying capacity of cities. The bearing capacity index of each subsystem changed with different forms. The economic subsystem highlighted the status of urban economic development. The higher the economic level, the higher the carrying capacity, the smaller the overall growth pattern. Due to the aggravation of floating population, the carrying capacity index of the social subsystem declined slightly. Based on the premise of relative stability of resources, the carrying capacity index of resource subsystem was relatively stable. The carrying capacity index of environmental subsystem showed a downward trend due to environmental pollution. Spatially, the differences of bearing capacity index of the subsystems in Guangdong were significant. The index of carrying capacity of economic and social composite system was basically matched with the economic development level of each city. Meanwhile, the index of carrying capacity of the composite system of resources and environment was roughly consistent with the topography of Guangdong, with the index being high in eastern and western Guangdong, and gradual decline in the Pearl River Delta in Dongguan and Shenzhen.

Key words: Sciurus vulgaris, molecular phylogeny, genetic diversity, molecular phylogeography.