A study of 30 years of records from New Zealand estuaries found that community stability was most strongly associated with species abundances changing at different times. No effect of species richness was detected, and the correlational result cannot be generalized directly to other coastal systems.
The Communications Biology study examined thirty years of benthic-invertebrate records from the monitored estuaries at regional, estuary and site scales. The researchers assessed community stability as average total abundance relative to its variation over time. The long record allowed the same communities to be compared across spatial scales and tested which biological pattern changed most consistently with stability, moving beyond a short-term snapshot.[1]
The strongest association was not with the number of species, but with different species reaching higher and lower abundances on different schedules. When declines in some species did not coincide with declines in others, total community abundance varied less. This asynchrony pattern was linked to stability at every scale examined, while the study detected no separate measurable effect of species richness.[1]
The data are observational and correlational; they do not prove that making species fluctuate at different times would stabilize an estuary. The results come from particular long-monitored tidal flats and cannot be transferred directly to other coastal systems. Their practical value is a measurable signal that monitoring should track how a community moves through time, not only how many species it contains. Local environmental conditions still need separate assessment.[1]
