The Simulation And Experiment Study Of Facilitation Mechanism And Its Response To The Discrepancies Of Species Traits

Positive interspecific interactions are commonplace.In recent years,ecologists have begun to realize their importance in determining community dynamics,community composition and ecosystem functioning.The researches of facilitation proved that the type of interspecific interactions shifts from competition to facilitation with the increase of environment severity. Although great efforts have been taken to develop the facilitation in both empirical field studies and theoretical work,there is still a large discrepancy among studies in target responses to the effects of neighbors,which may in part be due to the ecological attributes of the interacting species.Hence we introduced this issue to our study,used ecology model and field experiment at the same time,to exploring the mechanisms and the potential process of facilitation by functional groups.Finally we have obtained the following results:1) Facilitation expanded the realized niche of the competitive species into harsh environments by suppressing the stress-tolerant species.Most of their coexisting range are dominated by a positive effect of one species on another with a reciprocal negative effect from the species receiving the benefits on its benefactor ("+,-").2) In a subalpine grassland of Hezuo,the removal of Potentilla fruticosa shrub showed that shrub improve the biomass and structure of understory community effectively.And the magnitude of shrub facilitation significantly differed among three functional groups which beneath Potentilla fruticosa,while there was strong variation within all groups.These are due to the amelioration of microenvironment by shrubs.All results above indicate that the traits of species profoundly affect the interactions among species,show a new framework to investigate the interplay of facilitative and competitive interactions and their impacts on processes such as population dynamics and community organization.Then,they will provide feasible direction for recruitment and protection of alpine meadow.