Engen Steinar, Lande Russell, Walla Thomas, DeVries Philip J
Department of Mathematical Sciences, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
Am Nat. 2002 Jul;160(1):60-73. doi: 10.1086/340612.
The joint spatial and temporal fluctuations in the community structure of tropical butterflies are analyzed by fitting the bivariate Poisson lognormal distribution to a large number of observations in space and time. By applying multivariate dependent diffusions for describing the fluctuations in the abundances, the environmental variance is estimated to be very large and so is the strength of local density regulation. The variance in the lognormal species abundance distribution is partitioned into components expressing the heterogeneity between the species, independent noise components for the different species, a demographic stochastic component, and a component due to overdispersion in the sampling. In disagreement with the neutral theory, the estimates show that the heterogeneity component is the dominating one, representing 81% of the total variance in the lognormal model. Different spatial components of diversity, the alpha, beta, and gamma diversity, are also estimated. The spatial scale of the autocorrelation function for the community is of order 1 km, while sampling of a quadrat would need to be 10 km on a side to yield the total diversity for the community.
通过将双变量泊松对数正态分布拟合到大量时空观测数据，分析了热带蝴蝶群落结构的时空联合波动。通过应用多元相关扩散来描述丰度的波动，估计环境方差非常大，局部密度调节强度也是如此。对数正态物种丰度分布的方差被划分为几个部分，分别表示物种间的异质性、不同物种的独立噪声成分、种群统计随机成分以及抽样中过分散导致的成分。与中性理论不同的是，估计结果表明异质性成分是主导成分，占对数正态模型总方差的81%。还估计了多样性的不同空间成分，即α、β和γ多样性。群落自相关函数的空间尺度约为1公里，而要获得群落的总多样性，一个样方的边长需要达到10公里才能进行抽样。
