Compensatory dynamics in nature: A stabilizing role for interspecific competition

Unstable species populations may maintain stable community productivity if a decrease in one species is compensated by an increase in another. Theory indicates these “compensatory dynamics” stabilize productivity if species have different environmental responses but not different interspecific competitive effects. In contrast, observational studies indicate a stabilizing effect of interspecific competition. To resolve this apparent paradox we contextualize species tradeoffs in relation to resource and non-resource environmental variability. Greater interspecific competition under high resource conditions is stabilizing, whereas differential competition without resource variability is destabilizing. Because resource variability drives many species tradeoffs, interspecific competition may help stabilize productivity in nature.