Impacts of altered disturbance regimes on community structure and biodiversity mediated by fecundity–tolerance interactions

We present an investigation of the effects of disturbance and fecundity–tolerance strategies on community composition. We develop a theoretical model and apply it to macrofaunal communities at deep-sea hydrothermal vents. We characterize community outcomes and find that dominance, coexistence, and alternative stable equilibria can all result from the interplay of disturbance regimes and fecundity–tolerance interactions. We show that fecundity–tolerance trade-offs can permit coexistence under disturbance, but a strict fecundity–tolerance trade-off is not required for coexistence to arise. We further describe how coexistence depends on habitat availability and disturbance regimes. Generally, our model elaborates on fecundity–tolerance strategies as a new axis of trait variation in coexistence theory. Natural disturbance regimes vary considerably across regions, and anthropogenic disturbance to vent communities will escalate with the advent of deep-sea mineral extraction. We demonstrate how anthropogenic changes to disturbance regimes may impact species diversity, pushing communities over thresholds leading to local species extinction. Recommendations for Resource Managers. Conventional wisdom suggests that disturbance-adapted communities will not be strongly affected by novel perturbations associated with resource extraction or other human activities. We show that differing fecundity–tolerance strategies can mediate coexistence in disturbance-prone deep-sea environments, but that small changes to the disturbance regime can alter community composition and result in species extirpation. Natural disturbance should not be used as a rationale for expected low impacts of anthropogenic disturbance, for example, mining activities in management of deep-sea mineral extraction. Appropriate impact studies should be performed for all communities where disturbances, such as mining, are planned.