Effects of island area on plant species distribution and conservation implications in the Thousand Island Lake region
千岛湖库区岛屿面积对植物分布的影响及植物物种多样性保护研究

Numerous human activities have resulted in landscape fragmentation, and dam construction is one of them that often leads to drastic changes in biodiversity and ecosystem functioning on local and regional scales. In this study, we investigated how island area size affected the distribution of plant species in the Thousand Island Lake region. Also, we compared several conservation scenarios for maximizing plant species diversity. We found 56 tree species and 79 shrub species in 74 islands that were surveyed. These islands and the tree and shrub species they contained were tabulated by island size and analyzed consequently. Our results showed that 11 tree species were affected by island area while 15 were not, and 30 in between being affected and unaffected. For shrubs, 24 species were unaffected, 16 were affected, and 39 species were in between being affected and unaffected to variability in island size. Comparing the cumulative numbers of tree, shrub, and all species in different scenarios of aggregating individual islands by small, medium, large, and mixed categories, respectively, we were able to examine how species richness changed with the increasing total area of habitat and which combination gave rise to the highest species richness. Our analysis revealed that, for a given total area of island habitat, mixing islands of different sizes gave rise to the highest cumulative plant species richness in terms of tree, shrub, or total species richness. The agglomeration of smaller islands resulted in the second highest species richness whereas large islands supported the lowest species richness for the same total area of habitat. Thus, our results suggest that islands of all sizes need to be considered for biodiversity conservation in the Thousand Island Lake region.