Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide ...Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide more specific information about their environments.The objectives of this study are as follows:(i)to analyse and explain the spatial distribution patterns of conspecific trees in an old-growth subtropical karst forest;(ii)to investigate pattern changes at different spatial scales;(iii)to test the spatial pattern similarity(or dissimilarity)between trees at different abundances,diameter at breast height classes,canopy layers and different functional groups(shade tolerance and seed dispersal mode);(iv)to examine whether habitat heterogeneity has an important effect on the species spatial distribution.Methods The spatial distributions of woody species with≥20 individuals in a 1-ha subtropical karst forest plot at maolan in southwestern China were quantified using the relative neighbourhood densityΩbased on the average density of conspecific species in a circular neigh-bourhood around each species.Important Findingsaggregated distribution is the dominant pattern in the karst forest,but the ratio of aggregated species in total species number decreases with an increase in spatial scale.less abundant species are more aggregated than most abundant species.aggregation is weaker in larger diameter classes,which is consistent with the prediction of self-thinning.seed dispersal mode influences spatial patterns,with species dispersed by animals being less aggregated than those dispersed by wind and gravity.other species functional traits(e.g.shade tolerance)also influence the species spatial distributions.moreover,differences among species habitat associations,e.g.with rocky outcrops,play a significant role in species spatial distributions.These results indicate that habitat heterogeneity,seed dispersal limitation and self-thinning primarily contribute to the species spatial distributions in this subtropical karst forest.展开更多
基金One Hundred Talents Program of the Chinese Academy of Sciences to J.N.National Basic Research Program(973)of the China Ministry of Science and Technology(2006CB403207).
文摘Aims spatial distribution patterns of species reflect not only the ecological processes but also the habitat features that are related to species distribution.in karst topography,species distribution patterns provide more specific information about their environments.The objectives of this study are as follows:(i)to analyse and explain the spatial distribution patterns of conspecific trees in an old-growth subtropical karst forest;(ii)to investigate pattern changes at different spatial scales;(iii)to test the spatial pattern similarity(or dissimilarity)between trees at different abundances,diameter at breast height classes,canopy layers and different functional groups(shade tolerance and seed dispersal mode);(iv)to examine whether habitat heterogeneity has an important effect on the species spatial distribution.Methods The spatial distributions of woody species with≥20 individuals in a 1-ha subtropical karst forest plot at maolan in southwestern China were quantified using the relative neighbourhood densityΩbased on the average density of conspecific species in a circular neigh-bourhood around each species.Important Findingsaggregated distribution is the dominant pattern in the karst forest,but the ratio of aggregated species in total species number decreases with an increase in spatial scale.less abundant species are more aggregated than most abundant species.aggregation is weaker in larger diameter classes,which is consistent with the prediction of self-thinning.seed dispersal mode influences spatial patterns,with species dispersed by animals being less aggregated than those dispersed by wind and gravity.other species functional traits(e.g.shade tolerance)also influence the species spatial distributions.moreover,differences among species habitat associations,e.g.with rocky outcrops,play a significant role in species spatial distributions.These results indicate that habitat heterogeneity,seed dispersal limitation and self-thinning primarily contribute to the species spatial distributions in this subtropical karst forest.
