亚高寒草甸物种内稳性与生物量变化模式

Response of species homeostasis and biomass on a sub-alpine grassland

植物的内稳性与其在群落中的生态策略和适应性密切相关,然而从物种或功能群水平探讨内稳性与其竞争力关系的研究非常有限。本研究以青藏高原亚高寒草甸为例,通过N添加、P添加及N-P共添加的方式,选取4个功能群的10个物种,探讨养分添加下生物量变化规律及物种内稳性差异。结果显示,N添加及N-P共添加促进生物量的积累,而P添加抑制群落生物量的积累,说明该地区主要限制类型为N限制;N添加、P添加及N-P共添加均促进禾本科植物生物量的积累,而降低豆科及杂类草植物的生物量,其中仅N添加增加莎草科植物的生物量;P添加下,禾本科植物P内稳性强于其他物种,P内稳性可能在禾本科植物的竞争力上起到重要作用;其他处理及N、N∶P比未表现出一般性规律。因此,养分添加条件下,内稳性差异在高寒草甸物种竞争中可能并非主导因素。

Plant stoichiometric homoeostasis is correlated with dominance and stability in natural community. However,there is considerable limited work dealing with this relationship at species-level or function group-level. Study was made on the response of 10 dominant speicies from four function groups to N,P addition and N-P co-addition on a sub-alpine meadow in Tibetan Plateau. Results showed N and N-P addition promoted community biomass while P addition inhibited,indicating the N-limited type for grassland. Graminoid biomass increased,while legume and forb biomass decreased after either addition,and sedge biomass increased after N addition. The strong leaf P homeostasis of graminoid species may play a role in competition in the community. However,a regular rule on the leaf N homeostasis needs to be found out,and further study should be conducted to test the role of species homeostasis in the construction of community.