spaa: 计算生态位宽度

library(spaa) #用于分析物种关联和生态位重叠。
?spaa

#### Niche width and niche overlap
data(datasample)

#niche.width计算生态位宽度
niche.width(mat, method = c("shannon", "levins"))
#mat:列为物种，行为样本
#method:计算方法
niche.width(datasample[,1:3], method = "shannon")

  Castanopsis.eyrei Schima.superba Rhododendron.ovatum
1          2.003976        1.94466            1.776253

#每两个物种之间生态位的重叠
niche.overlap(mat, method = c("levins", "schoener", 
                              "petraitis", "pianka", "czech", "morisita"))
niche.overlap(datasample[,1:3], method = "levins")

                    Castanopsis.eyrei Schima.superba
Schima.superba              0.9206029               
Rhododendron.ovatum         0.9473341      0.7721003

#niche.overlap.boot也是计算生态位重叠，只是增加了bootstrap值，用法一样。