Most suitable landscape patterns to preserve indigenous plant diversity affected by increasing urbanization: A case study of Shunyi District of Beijing, China

Abstract

The effects of urbanization on plant diversity have been increasingly investigated around the world, but our knowledge of the performances of urbanized landscape is still inadequate for suitable urban landscape planning and management. We asked: 1) what are the effects of urbanized landscape pattern on indigenous plant diversity, and 2) do these effects exhibit scale dependence? A total of 105 plots, distributed throughout the study area were chosen. Each plot was 10 m × 10 m. Alpha-diversity, and beta-diversity of species taxonomic composition across plots was calculated. Four groups of landscape metrics (complexity, fragmentation, diversity, and urbanization intensity) were measured for each plot. Ten scales, ranging from 100 m to 1000 m and with increasing steps of 100 m, were used as spatial scales. Pearson’s correlation analyses were used to detect relationships between the indigenous plant diversity along the urbanization gradient and the ten landscape metrics. Shannon’s Diversity Index (SDI), Shannon’s Evenness Index (SEI), Edge Density (ED), and Landscape Shape Index (LSI) were highly and positively correlated with alpha and beta plant diversity, whereas Largest Patch Index (LPI) were negatively correlated with plant diversity. Such correlations became stronger at higher spatial scales, and the highest at 600–700 m. The intensity of urbanization increased the values of ED and LPI in urbanized landscape and negatively influenced plant diversity. The correlations were influenced by the spatial extent. The study offers some guidelines on landscape pattern, including patch size, shape, and its configuration, in managing urban areas optimally to support plant diversity and wildlife. Landscape unit with diverse land uses with a radius of 600–700 m for Beijing, and other specific radius for other cities in the world are proposed as the most suitable landscape pattern for preserving indigenous plant diversity.