植物功能群多样性而非物种丰富度决定群落可入侵性OACHSSCD

Numerous experiments had been conducted to investigate how plant diversity affected community invasibility,while the findings of these experiments remained inconsistent.To investigate the mechanism through which plant diversity influenced community invasibility,we selected eight species:Plantago asiatica L.,Solanum nigrum Linn.,Cirsium setosum(Willd.)Bess.ex M.Bieb.,Kalimeris indica(L.)Sch.-Bip.,Lysimachia fortunei Maxim.,Inula japonica Thunb.,Polygonum posumbu Buch.-Ham.ex D.Don,and Viola philippica Cav.,which belong to four functional groups:early tall type,late tall type,early dwarf type,late dwarf type.Two experimental treatments were constructed:one in which species richness(SR)increased with functional group richness(FGR)(FGR:1,2,3,4;corresponding SR:1,2,4,8),and another in which SR did not increase with FGR(FGR:1,2,3,4;corresponding SR:1,4,4,4).This design allowed us to disentangle the relative roles of SR and FGR in invasion resistance.Soil organic matter(SOM),total nitrogen(TN),total phosphorus(TP),and the biomass of both native and invasive species Solidago canadensis L.were measured.Diversity effect(the complementarity and selection effects)was calculated to analyze the relative role of SR and FGR.The results showed that,regardless of whether SR increased,the biomass of S.canadensis significantly decreased with increasing FGR.FGR had no significant relationship with the complementarity effect but was negatively correlated with the selection effect.In both treatment of SR increased and not increased with FGR,functional composition had a significant effect on the biomass of S.canadensis.Moreover,functional group composition had no significant effect on the complementarity effect,but significantly influenced the selection effect.In both treatment of SR increased and not increased with FGR,the presence of Kalimeris indica or/and Polygonum posumbu significantly decreased the biomass of S.canadensis.Phosphorus utilization efficiency of communities was significantly negatively correlated with the biomass of S.canadensis.However,no significant relationship was found with nitrogen and carbon utilization efficiency.These findings indicated that functional group diversity played a critical role in community invasion resistance and that functional group composition might affect the invasion of S.canadensis by regulating phosphorus resource use.This study has significant theoretical importance for investigating the intrinsic mechanisms by which plant diversity resists invasion,and provides new theoretical perspectives and explanatory pathways for resolving controversies in research on the relationship between plant diversity and community invasibility.