环境因子影响下疏勒河上游高寒草甸物种丰富度与生物量间的关系

生物多样性与生产力的关系是生态学领域争论不休的重要科学问题.调查了青藏高原疏勒河上游高寒草甸典型植物群落物种丰富度、生物量及环境因子,分析了不同植物群落物种丰富度与生物量的关系及其差异性,并探讨了影响两者间关系的关键环境因子.结果表明:1)以莎草科或毛茛科物种为主要建群种的植物群落物种丰富度与生物量不存在显著的相关性(P0.05),如高山嵩草+苔草群落、线叶嵩草+黑褐苔草群落、唐松草+矮火绒群落、草苔草+昆仑蒿群落;而以禾本科为建群种的植物群落(紫花针茅+紫菀群落、紫花针茅+沙生风毛菊群落)两者间存着显著正相关性(P0.05).2)CCA排序中,环境因子对植物群落分布格局的累计解释量为83.4%,这说明环境异质性是影响植物群落空间格局的主要原因,其中冻土上限埋深是影响植物群落特征及分布的关键环境因子.冻土上限埋深小于-4 m时,丰富度与生物量间存在着显著的正相关;冻土上限埋深大于-4 m时,两者间无显著相关性.这有助于深刻认识生物多样性与高寒草甸生态系统功能的关系.

Relation between species richness and biomass in alpine meadow in the upper reaches of the Shule River under the effects of environmental factors

The relation between diversity and productivity is a controversial issue in ecology.In this study,the species richness,biomass and key environmental factors of typical plant communities are investigated in alpine meadow in the upper reaches of the Shule River on the Tibetan Plateau.The aims of this study are to examine the relation between species richness and biomass in different plant communities and to evaluate the effects of key environmental factors on the relation.It is found that:1) There are no significant correlation between species diversity and productivity in the plant communities,which are constructed by the plant species of Cyperaceae family or Ranunculaceae family,such as Kobresia pygmaea + Carex qinghaiensis comm.,Kobresia capillifolia + Carex atrofusca comm.,Thalictrum aquilegifolium + Leontopodium nanum comm.and Carex qinghaiensis + Artemisia nanshanica comm.However,the relation between species richness and biomass shows significantly positive correlation in the plant communities,which are constructed by Gramineae family species,such as Stipa purpurea + Aster tataricus comm.and Stipa purpurea + Saussurea arenaria comm.2) In the CCA ordination analysis,the accumulative interpretation amount of the environmental factors on the plant community distribution pattern reaches 83.4％,which demonstrates that the environmental heterogeneity result in the plant communities distribution;furthermore,the depth of the active layer of permafrost (denoted as PF) is the most important factor to explain the distribution of plant communities.Notably,when PF is more than-4 m,there is no significant correlation between species richness and biomass,whereas,when PF is less than-4 m,the species richness-biomass relation is significantly positive correlation.These results might be helpful to deeply understand the relation between biodiversity and ecosystem function in alpine meadow.