Responses Of Metacommunities With Competition-colonization Tradeoffs To Dynamic And Static Disturbances

Disturbance is often viewed as a key driver of biodiversity maintenance in community ecology.Among them,the classical intermediate disturbance hypothesis(IDH)predicts that moderate disturbance can maximize species diversity in competition-colonization tradeoff communities,while further increasing or decreasing disturbance results in a decline in biodiversity,thereby shaping the unimodal disturbance-diversity relationship(DDR).Currently,numerous empirical studies have been performed to verify the IDH,but few experiments support this hypothesis,and such IDH cannot explain other disturbance-diversity relationships observed by experiments.As such,the IDH is being greatly challenged and questioned.Thus,the precise relationship between disturbance and biodiversity remains a topic of debate.Meanwhile,a systematic mechanistic explanation for other empirically-observed DDRs is still lacking.This study constructs a patch occupancy dynamic model for metacommunities based on the classic competition-colonization(C-C)tradeoff,by combining both static and dynamic disturbances.Using this model,this study explores the response modes and the driving mechanism of DDRs.Theoretical studies showed that species diversity display multi-peaked characteristics along the gradients of both dynamic and static disturbances,and such multimodal patterns in biodiversity are quite robust.Apparently,the multimodality arises from the oscillations in species’ relative abundances,but ultimately,they come down to the interaction between disturbance and C-C tradeoffs.To verify the multimodality predicted above,this study collected and compiled a large empirical dataset for meta-analysis.The initial statistical analysis shows diverse responses of biodiversity to disturbance,such as a monotonic increase or decline,neutrality,U-shape or oscillations.Then,all these empirical studies are categorized by the type of system,habitat and geographic location,respectively,finding that the biodiversity responses to disturbance are still diverse,including positive,negative and even neutral.As the predicted multimodality in DDRs covers all kinds of responses observed in experiments,this meta-analysis indirectly demonstrates these modelling predictions.In summary,using both theoretical prediction and empirical meta-analysis,this study demonstrates the multi-peaked characteristic in DDRs,in stark contrasting to the unimodal pattern predicted by the classic IDH.At the same time,this study theoretically analyzes changes in species’ relative abundances along the disturbance gradient,thereby revealing the inherent mechanism of biodiversity responses to disturbance in metacommunities.Therefore,this study facilitates our understanding of the DDR,providing both theoretical basis and decision support for biodiversity conservation and management.