Ecological Changes with Minor Effect Initiate Evolution to Delayed Regime Shifts.

Regime shifts have been documented in a variety of natural and social systems. These abrupt transitions produce dramatic shifts in the composition and functioning of socioecological systems. Existing theory on ecosystem resilience has only considered regime shifts to be caused by changes in external conditions beyond a tipping point and therefore lacks an evolutionary perspective. In this study, we show how a change in external conditions has little ecological effect and does not push the system beyond a tipping point. The change therefore does not cause an immediate regime shift but instead triggers an evolutionary process that drives a phenotypic trait beyond a tipping point, thereby resulting (after a substantial delay) in a selection-induced regime shift. Our finding draws attention to the fact that regime shifts observed in the present may result from changes in the distant past, and highlights the need for integrating evolutionary dynamics into the theoretical foundation for ecosystem resilience. Incorporating evolutionary dynamics into a population model, the authors show that, even though changing ecological conditions are not enough to induce an immediate regime shift in the system, selection-induced evolutionary responses acting on a phenotypic trait may eventually cause a regime shift by pushing it beyond a tipping point after a substantial delay.