Data from: Long-term data suggest jarrah-forest establishment at restored mine sites is resistant to climate variability

1. Global climate change is projected to increase the frequency and
intensity of drought in dry regions due to warming temperatures and
declining rainfall. Severe drought can trigger tree mortality and drive
persistent vegetation change. 2. To date, most empirical studies have
focused on drought-induced mortality of adult trees, but this needs to be
matched by similar efforts to understand drought impacts on seedling
establishment if we are to understand the resilience of the world's
forests to projected climate change. 3. The Eucalyptus marginata
(jarrah)-forest ecoregion of south-western Australia has experienced a 17%
reduction in mean annual rainfall from 1975 to 2011 compared with mean
rainfall from 1900 to 1974. Drought-induced mortality of adult trees has
been documented for jarrah forest, but there is limited understanding of
its capacity to recover, making it difficult to predict the likelihood of
persistent effects. 4. Long-term records of jarrah-forest restoration
following bauxite mining are available for the 19-year period between 1992
and 2010. Records include annual data on seedling establishment in
restored mine sites for 587 species in 1938 plots during a period of
climatic variability. 5. We built a structural equation model to
discriminate the relative effects of climate, restoration practice, and
their interactive effects on three response variables including species
richness of the restored plant assemblages. Climate variability had a
significant negative effect on richness, but the effect size was
relatively small, being less than half that of varying restoration
practice. We suggest this is due, in part, to the reliability of rainfall
(i.e. no change in the coefficient of variation, seasonality or evenness,
between recent and historical climates) despite a threefold difference in
the absolute amount of wet-season rainfall. Importantly, there was no
evidence that restoration practices were compromised by interacting
effects of increased climate variability. 6. Synthesis. Jarrah-forest
establishment in a restoration context appears resistant to recent changes
in climate. Our research highlights the importance of deriving multiple
metrics of climate change to understand community responses. In
particular, rainfall reliability should be a focus of future research to
determine its broader significance to seedling establishment in forests
subject to a drying climate.