Scale- and intensity-dependent disturbance determines the magnitude of opportunistic response

Opportunistic, fugitive or pioneer species are species that posses life-history characteristics that allow them to respond quickly to disturbances. Their abundance during the early stages of succession is central to ecological models of benthic soft-sediment succession and these species can play important roles in affecting subsequent successional trajectories. Nevertheless, numerous studies have demonstrated seemingly random patterns of opportunistic responses following disturbance, questioning the generality of currently accepted successional models. In this paper we provide examples from two case studies and argue that the spatial scale or magnitude of disturbance is key to the development of opportunistic responses, and that the scale of disturbance may be particularly important in determining (a) the levels of resources made available and (b) the magnitude of release from competitive interactions, which permit opportunists to flourish.