Impacts of the remnant sizes, forest types, and landscape patterns of surrounding areas on woody plant diversity of urban remnant forest patches

摘要

Remnant forests in urban areas are hotspots of urban biodiversity. However, the survival and integrity of many remnant forests are currently at risk. Better knowledge of the interactions between remnant forests and urban environments is urgently needed for guiding the conservation effort. In this study, we intend to answer the question: how do patch attributes and landscape patterns of surrounding environments affect the taxonomic diversity of woody plants in urban forest remnants? We surveyed the woody plant species in 240 sample plots in 54 remnant forest patches in Guiyang City, China. We analyzed the taxonomic diversity of woody plants and the effects of influencing factors using multi-level taxonomic diversity indicators and the generalized dissimilarity modeling. The results showed that shrubs had higher within-patch alpha-diversity than that of trees. However, adult trees had higher among-group beta-diversity than those of shrubs and saplings/seedlings. The vegetation type of the patch had more influence than other factors on the compositional dissimilarity of adult trees and sapling/seedling among patches. The patch size had the highest impact on the compositional dissimilarity of shrubs. Besides, small patches had a higher rate of compositional turnover in all woody plants. The percentage of impervious surfaces in surrounding areas and the spatial distance from each other were the main influencing factors for adult trees and saplings/seedlings, respectively. Based on our results, we recommend that more attention should be paid to preserve the small remnant forest patches and protect sampling/seedlings to maintain the taxonomic diversity of urban remnant forests.