Data from: Environmental heterogeneity leads to higher plasticity in dry-edge populations of a semiarid Chilean shrub: insights into climate change responses

1.Interannual variability in climatic conditions should be taken into
account in climate change studies in semiarid ecosystems. It may determine
differentiation in phenotypic plasticity among populations, with
populations experiencing higher environmental heterogeneity showing higher
levels of plasticity. 2.The ability of populations to evolve key
functional traits and plasticity may determine the survival of plant
populations under the drier and more variable climate expected for
semiarid ecosystems. 3.Working with populations of the semiarid Chilean
shrub Senna candolleana along its entire distribution range, we assessed
inter- and intra-population variation in functional traits as well as in
their plasticity in response to water availability. We measured
morphological and physiological traits related to drought resistance in
both field conditions and in a greenhouse experiment, where drought
response was evaluated under two water availability treatments. 4.All
populations responded plastically, but higher precipitation heterogeneity
in dry-edge populations seemed to have selected for more plastic genotypes
compared to populations growing at mesic sites and with more homogeneous
environmental conditions. 5.Synthesis: Our results suggest adaptive
plasticity since higher levels of phenotypic plasticity were positively
associated with plant performance. However, we did not find evidence for
genetic variation for plasticity within populations. To the extent that
phenotypic plasticity may play a key role in future persistence,
populations at mesic sites may be more vulnerable to climate change due to
their lower plasticity and their current limitations to evolve novel norms
of reaction. Conversely, although Senna candolleana populations at the
dry-edge are exposed to higher levels of stress, they may be less
susceptible to climate change in view of their greater plasticity. We
highlight the need to consider population differentiation in both mean
traits and their plasticity to model realistic scenarios of species
distribution under climate change.