Recent meta-analyses have shown that beta diversity through space is jointly driven by species traits, geographical gradients and ecosystem properties. Spatial variation is, however, only one aspect of beta diversity. The other component is variation in communities through time, that is, temporal turnover. We examined the decrease of community similarity in time in aquatic communities in relation to several ecological, physical and geographical factors using an extensive data set derived from literature. The data set was first divided into intra-annual and interannual parts depending on the temporal extent of the studies.
Results/Conclusions
Sampling duration was one the most significant variables affecting the degree of temporal turnover and we found that turnover was faster in studies with the smaller temporal extent. Our results further suggested that the rate of temporal turnover increased with the increasing ecosystem size thus contradicting with the general species-time-area relationship. Temporal turnover also varied among the ecosystem types as lake communities showed faster turnover than stream or marine communities in interannual data set. We also found that temporal turnover exhibited large-scale geographical variation as there was a latitudinal gradient in turnover. Turnover was faster in tropics in the intra-annual data set but the pattern was reversed in the interannual data set, where turnover was faster at high latitudes. Finally, we found that the degree of temporal turnover was related to organism characteristics as larger organisms with active mobility showed slower temporal turnover than the smaller organisms. Our results suggest that the degree of species turnover in time is jointly driven by several ecological, physical and geographical factors in aquatic ecosystems and that the turnover is not uniform across taxonomic groups. Present results are important for understanding of how fast different biotic communities track changes in environment and how resilient communities are towards environmental changes.
