【摘要】 由于水库蓄水导致千岛湖原有生境的破碎化和岛屿化。研究选取了50个岛屿,共设立样方70个。调查这些岛屿上乔木和灌木的种类及数量,选择9种曲线拟合岛屿面积与物种多样性指数之间的数学关系。结果发现:乔木、灌木和木本物种数与岛屿面积关系拟合较好的是对数函数、幂函数和S型曲线,其中对数函数为最优模型;乔木、木本Shannon-Wiener多样性指数与岛屿面积关系拟合较好的是S型曲线和逆函数,灌木Shannon-Wiener多样性指数与岛屿面积关系拟合不显著,乔木和木本Shannon-Wiener多样性指数与较小岛屿(y小于1 hm2)面积拟合呈S形曲线和逆函数,而灌木Shannon-Wiener多样性指数与较大岛屿(y大于1 hm2)面积拟合呈S形曲线和逆函数;均匀度、优势度指数与面积拟合关系不显著。在岛屿面积较小时,物种多样性指数随着面积的增加而迅速增加,但在面积增加到一定限度时,物种多样性指数增加的速率就逐渐变缓。植物物种数增加速率的转折点约为4 hm2,乔木、木本Shannon-Wiener多样性指数增加速率的转折点约为1 hm2,对面积小于的1 hm2的岛屿进行拟合时发现,乔木、木本Shannon-Wiener多样性指数增加速率的转折点在0.15～0.2 hm2之间。更多还原

【Abstract】 The Thousand-Island Lake was formed by dam construction that resulted in habitat fragmentation,that is,the formation of islands surrounded by water.We sampled trees and shrubs on 50 islands in the lake to examine relationships between island areas and species diversity with various curve fitting methods.Our results showed that logarithmic functions,power functions and S-type curves adequately described the relationship between island area and plant(trees,shrubs,and woody species) species richness,with logarithmic functions being the optimal model.S-type curves and inverse functions depicted relationships between Shannon-Wiener index of trees and woody plants and island area reasonably well,but were not good depictions of relationships between Shannon-Wiener index of shrubs and island area.On islands less than 1 hm2,the best species-area models were S-type curves and inverse functions for Shannon-Wiener index of trees and woody species;the same applies to Shannon-Wiener index of shrubs on islands larger than 1 hm2.The relationships between Simpson index or Pielou index of trees,shrubs,and woody plants and island area were not significant.Species diversity index increased rapidly with island size for small islands,but much more slowly for large islands.For all plants,the turning point of the rate of increase in species richness was about 4 hm2.For trees and woody species,the turning point of the rate of increase in Shannon-Wiener index was about 1 hm2,and was about 0.15-0.2 hm2 when only islands less than1 hm2 were considered.更多还原