Anthropogenic factors explain urban plant diversity across three tropical cities in China

Urban plants are important for the aesthetics and functionality of the urban environment and are closely related to human life. To help fill the current research void on the distribution patterns and driving mechanisms of urban plant diversity in the tropics, we tested the relationship between plant species richness and land use and anthropogenic and environmental factors in 491 urban functional units (UFUs) in three tropical cities in China (i.e., Zhanjiang, Haikou, and Sanya). The results showed highly significant differences in the distribution of plant richness between different land use types, with the high plant diversity found in residential areas, and leisure and entertainment areas. A positive relationship was found between construction age and spontaneous plant species richness. Furthermore, housing price, trimming and fertilizing frequencies were positively related with cultivated species richness and negatively related with spontaneous species richness. We conclude that urban plant species richness is not the result of a single factor but is influenced by the interaction between anthropogenic factors and environmental factors; although anthropogenic factors play the largest role in determining patterns of urban plant diversity. These results can help decision-makers and managers better understand the current spatial patterns of urban plant diversity, in order to establish and manage urban green space more scientifically and realize sustainable development of urban green space.