长苞铁杉林林隙主要树种生态位初步研究

以林隙前、中、后期3个发育阶段的各个林隙为一维资源位状态,利用Shannon-wiener指数、Levins指数及生态位重叠公式,计算林隙不同发育阶段主要树种生态位特征。结果表明,前期生态位宽度从大到小的顺序为:长苞铁杉、米槠、木荷、甜槠、深山含笑、香桂、青冈、猴头杜鹃、山矾、细叶青冈;中期的为:米槠、木荷、长苞铁杉、香桂、深山含笑、山矾、甜槠、猴头杜鹃、青冈、细叶青冈;后期的为:米槠、木荷、长苞铁杉、青冈、山矾、香桂、深山含笑、细叶青冈、甜槠、猴头杜鹃;林隙发育的不同时期主要树种生态位重叠值均较大,但随着林隙的不断发育,主要树种间生态位重叠值有减小的趋势;长苞铁杉在林隙发育的不同阶段与生态位宽度较大的物种有较小的生态位重叠值,而与生态位宽度较小的物种有较大的生态位重叠值。

Ecological Niche in Dominant Species in Tsuga longibracteata Forest Gaps with Different Development Stages

Shannon-wiener index, Levins index and comparability proportion formula were used to study niche breadth and niche overlap of dominant species in Tsuga longibracteata forest gaps at different stages. Tsuga longibracteata, an endemic to China species of Pinaceae, is distributed at the uppermost layer of forest, which makes it difficult to regenerate naturally. The study of ecological niche in gaps of T. longibracteata forest is to understand the change in population number of some species, the regeneration of which depends on gaps, and to protect the forest resource more effectively. The sites studied were located in Tianbaoyan National Nature Reserve in Fujian Province. Twenty one gaps, with quadrats of 80 m2 each were investigated. The results revealed that niche breadth of main trees in gaps varied at different stages of gap development. At early stage, niche breadth of tree species declined in the following order: Tsuga longibracteata, Castanopsis carlesii, Schima superba,Castanopsis eyrei, Michelia maudiae, Cinnamomum subavenium, Cyclobalanopsis glauca, Rhododendron iniarum, Symplocos sumuntia, Cyclobalanopsis myrsinaefolia; at the middle stage, in the descending order of: Castanopsis carlesii, Schima superba, Tsuga longibracteata, Cinnamomum subavenium, Michelia maudiae, Symplocos sumuntia, Castanopsis eyrei, Rhododendron iniarum, Cyclobalanopsis glauca, Cyclobalanopsis myrsinaefolia; while at the late stage, Castanopsis carlesii, Schima superba, Tsuga longibracteata, Cyclobalanopsis glauca, Cyclobalanopsis myrsinae, Cinnamomum subavenium, Michelia maudiae, Cyclobalanopsis myrsinaefolia, Castanopsis eyrei,Rhododendron iniarum. High values of niche overlap were shown in all trees in gaps with different stages, but thenthe values declined with the gap development. Less niche overlap values were shown in T. longibracteata compared to those species with higher niche breadth, but more to those with lower niche breadth.