* Premise of the study: Near-future climate changes are
likely to elicit major vegetation changes. Disequilibrium dynamics, which occur
when vegetation comes out of equilibrium with climate, are potentially a key
facet of these. Understanding these dynamics is crucial for making accurate
predictions, informing conservation planning, and understanding likely changes
in ecosystem function on time scales relevant to society. However, many
predictive studies have instead focused on equilibrium end-points with little
consideration of the transient trajectories.
* Methods: We review
what we should expect in terms of disequilibrium vegetation dynamics over the
next 50–200 yr, covering a broad range of research fi elds including
paleoecology, macroecology, landscape ecology, vegetation science, plant
ecology, invasion biology, global change biology, and ecosystem ecology.
* Key results: The
expected climate changes are likely to induce marked vegetation disequilibrium
with climate at both leading and trailing edges, with leading-edge
disequilibrium dynamics due to lags in migration at continental to landscape
scales, in local population build-up and succession, in local evolutionary
responses, and in ecosystem development, and trailing-edge disequilibrium
dynamics involving delayed local extinctions and slow losses of ecosystem
structural components. Interactions
with habitat loss and invasive pests and pathogens are
likely to further contribute to disequilibrium dynamics. Predictive modeling
and climate-change experiments are increasingly representing disequilibrium
dynamics, but with scope for improvement.