Diversity is maintained by seasonal variation in species abundance

Hideyasu Shimadzu,Peter A Henderson,Maria Dornelas,Anne E Magurran

doi:10.1186/1741-7007-11-98

Abstract

BackgroundSome of the most marked temporal fluctuations in species abundances are linked to seasons. In theory, multispecies assemblages can persist if species use shared resources at different times, thereby minimizing interspecific competition. However, there is scant empirical evidence supporting these predictions and, to the best of our knowledge, seasonal variation has never been explored in the context of fluctuation-mediated coexistence.ResultsUsing an exceptionally well-documented estuarine fish assemblage, sampled monthly for over 30 years, we show that temporal shifts in species abundances underpin species coexistence. Species fall into distinct seasonal groups, within which spatial resource use is more heterogeneous than would be expected by chance at those times when competition for food is most intense. We also detect seasonal variation in the richness and evenness of the community, again linked to shifts in resource availability.ConclusionsThese results reveal that spatiotemporal shifts in community composition minimize competitive interactions and help stabilize total abundance.

Highlights

Some of the most marked temporal fluctuations in species abundances are linked to seasons
Most of the focus on seasonal variation in species relates to phenology, in the context of climate change
Temporal variation is inherent in the intermediate disturbance hypothesis, which proposes that competitive exclusion can be constantly postponed by disturbance [12]

Summary

Introduction

Some of the most marked temporal fluctuations in species abundances are linked to seasons. There is a long history behind the idea that temporal variation in environmental conditions and species abundance enables species to coexist It was for example discussed by Hutchinson [11] as a phenomenon that might help resolve the paradox of the plankton. It is clear that the intermediate disturbance hypothesis has little empirical and theoretical support [13], there are mechanisms by which species can coexist through temporal niche partitioning. These are known as fluctuation dependent mechanisms of coexistence (FMC) [14], and predict the conditions under which multispecies communities can stably persist

Methods

Results

Conclusion