Assessing the vulnerability of plant functional trait strategies to climate change

Aim: Our ability to understand how species may respond to changing climate
conditions is hampered by a lack of high-quality data on the adaptive
capacity of species. Plant functional traits are linked to many aspects of
species life history and adaptation to environment, with different
combinations of trait values reflecting alternate strategies for adapting
to varied conditions. If the realised climate limits of species can be
partially explained by plant functional trait combinations, then a new
approach of using trait combinations to predict the expected climate
limits of species trait combinations may offer considerable benefits.
Location: Australia. Time period: Current and future. Methods: Using trait
data for leaf size, seed mass and plant height for 6,747 Australian native
species from 27 plant families, we model the expected climate limits of
trait combinations and use future climate scenarios to estimate climate
change impacts based on plant functional trait strategies. Results:
Functional trait combinations were a significant predictor of species
climate niche metrics with potentially meaningful relationships with two
rainfall variables (R2 = 0.36 & 0.45) and three temperature
variables (R2 = 0.21, 0.28, 0.30). Using this method, the proportion of
species exposed to conditions across their range that are beyond the
expected climate limits of their trait strategies will increase under
climate change. Main conclusions: Our new approach, called Trait Strategy
Vulnerability, includes three new metrics. For example, the Climate Change
Vulnerability (CCV) metric identified a small but important proportion of
species (4.3%) that will on average be exposed to conditions beyond their
expected limits for summer temperature in the future. These potentially
vulnerable species could be high priority targets for deeper assessment of
adaptive capacity at the genomic or physiological level. Our methods can
be applied to any suite of co-occurring plants globally.