Interval squeeze: altered fire regimes and demographic responses interact to threaten woody species persistence as climate changes

Projected effects of climate change across many ecosystems globally include more frequent disturbance byfire and reduced plant growth due to warmer (and especially drier) conditions. Such changes affect species– particularly fire-intolerant woody plants – by simultaneously reducing recruitment, growth, and survival.Collectively, these mechanisms may narrow the fire interval window compatible with populationpersistence, driving species to extirpation or extinction. We present a conceptual model of these combinedeffects, based on synthesis of the known impacts of climate change and altered fire regimes on plantdemography, and describe a syndrome we term “interval squeeze”. This model predicts that intervalsqueeze will increase woody plant extinction risk and change ecosystem structure, composition, and carbonstorage, especially in regions projected to become both warmer and drier. These predicted changesdemand new approaches to fire management that will maximize the in situ adaptive capacity of species torespond to climate change and fire regime change.