Data from: Resistance and resilience to changing climate and fire regime depend on plant functional traits

Changing disturbance-climate interactions will drive shifts in plant
communities: these effects are not adequately quantified by environmental
niche models used to predict future species distributions. We quantified
the effects of more frequent fire and lower rainfall - as projected to
occur under a warming and drying climate - on population responses of
shrub species in biodiverse Mediterranean-climate type shrublands near
Eneabba, southwestern Australia. Using experimental fires, we measured the
density of all shrub species for four dominant plant functional groups
(resprouter/non-sprouter x serotinous/soil seed bank) before and after
fire in 33 shrubland sites, covering four post-fire rainfall years and
fire intervals from 3 – 24 years. Generalized linear mixed effects models
were used to test our a priori hypotheses of rainfall, fire interval, and
plant functional type effects on post-fire survival and recruitment. At
shortened fire intervals, species solely dependent on seedling recruitment
for persistence were more vulnerable to local extinction than were species
with both seedling recruitment and vegetative regrowth. Nevertheless,
seedling recruitment was essential for population maintenance of
resprouting species. Serotinous species were less resilient than soil seed
storage species regardless of regeneration mode. Critically, in relation
to changing climate, a 20% reduction in post-fire winter rainfall
(essential for seedling recruitment) is predicted to increase the minimum
inter-fire interval required for self-replacement by 50%, placing many
species at risk of decline. Synthesis. Our results highlight the
potentially deleterious biodiversity impacts of climate and fire regime
change, and underscore weaknesses inherent in studies considering single
impact factors in isolation. In fire-prone ecosystems characterized by a
projected warming and drying climate, and increasing fire hazard, adaptive
approaches to fire management may need to include heightened wildfire
suppression and lengthened intervals for prescribed fire to best support
the in situ persistence of perennial plant species and of plant
biodiversity. This conclusion is at odds with the view that more managed
fire may be needed to mitigate wildfire risk as climate warms.