Spatial Heterogeneity of Plant Diversity within and between Neighborhoods and Its Implications for a Plant Diversity Survey in Urban Areas

The spatial heterogeneity of plant diversity at the neighborhood scale has less been understood, although it is very important for the planning and management of neighborhood landscape. In this case study of Beijing, we conducted intensive investigations of the plant diversity in different neighborhoods along a rural-urban gradient. The results showed that the mean numbers of plant species per neighborhood were 30.5 for trees, 18.8 for shrubs, and 31.9 for herbs, respectively. There were significant logarithmic relationships between the numbers of species and patch area, indicating that larger patches within neighborhoods could harbor more plant species. Hierarchical linear modeling showed that the variations in plant diversity within neighborhoods were higher than those between neighborhoods. The number of species increased logistically with both the number of patches within neighborhoods and the number of neighborhoods, suggesting that it is important to sample a sufficient number of patches within neighborhoods, as well as a sufficient number of neighborhoods in order to sample 90% of the plant species during the investigation of plant diversity in urban neighborhoods. So the hierarchical design of sampling should be recommended for investigating plant diversity in urban areas.