中国湿地物种多样性与生境面积关系及其生态学机理的模拟研究

Species-area relationship of Chinese wetlands and its theoretical simulation

生物群落中的物种多样性是群落生态学研究的一个基本问题 .大量的实验研究表明物种多样性和生境面积的常数次幂成比例 ,这说明它们的对数数量级呈线性正相关 .我们研究了中国境内 1 5块湿地的高等植物和 32块湿地鸟类多样性 ,发现它们分别和湿地面积在对数尺度上呈线性正相关 ,进一步支持了种数与面积的幂指数关系 .我们还借助计算机模拟系统地讨论了产生这种简单规律的生态学机理 ,包括中性理论、集合种群动态和物种分布的自相似性 .中性理论假设了群落中物种的个体之间只有竞争关系 ,忽略了其它的种间关系 .集合种群动态理论考虑的是由多个亚群落构成的集合群落 ,在研究种数和面积关系时也忽略了种间关系 ,所以也是中性的 .尽管物种分布的自相似性可导致这种面积幂指数关系 。

The relationship between species diversity and habitat area is a fundamental question in community ecology.Many experiential observations have showed that the number of species has a power correlation with the area of habitat.This rule implies that the logarithmic relationship between species richness and habitat area is linear.The slope generally ranges from 0.18 to 0.35,the average of which is about 0.25 .We studied the high plant diversity in 15 pieces of wetland and the avian diversity in 32 pieces of wetland in China.It was found that the high plant diversity was significantly linearly correlative with wetland area on logarithmic scale,and that the avian diversity had similar result.But the slope of the former is 0.296 9 ,contrasted to the latter 0.239 5.These results experientially support the species area power rule again.We also discussed the mechanisms leading to the power relationship in terms of computer simulation,including neutral theory,metapopulation dynamic theory,and self similarity of spatial distribution of species.Neutral theory considers communities of ecological similar species in which individuals compete with each other,yet it does not have other interactions,such as trophic interactions.Metapopulation dynamics describes a community comprising many sub communities that are connected through migrations of individuals among them.It is naturally neutral because of ignoring interspecific interactions.The observed patterns in simulation with a neutral model or metapopulation model all agree to species area power ruler.Self similarity of specific distribution that leads to species area relationship refers to the fraction of species in an area that are also found in one half of that area is independent of the area.However,the self similarity does not always hold,such as tree species in tropic forest.