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 by
fire 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 population
persistence, driving species to extirpation or extinction. We present a conceptual model of these combined
effects, based on synthesis of the known impacts of climate change and altered fire regimes on plant
demography, and describe a syndrome we term “interval squeeze”. This model predicts that interval
squeeze will increase woody plant extinction risk and change ecosystem structure, composition, and carbon
storage, especially in regions projected to become both warmer and drier. These predicted changes
demand new approaches to fire management that will maximize the in situ adaptive capacity of species to
respond to climate change and fire regime change.