Data for: Adaptive plasticity to drought of Grime’s CSR strategies

Grime’s strategies (Competitor, Stress tolerator, Ruderal; CSR) represent
viable trait combinations with which species deal with environmental
conditions. CSR strategies are broadly used to understand plant adaptation
to the environment, yet their plastic responses have received little
attention. A globally-calibrated tool (StrateFy) estimates CSR strategies
using specific leaf area (SLA), leaf dry matter content (LDMC) and leaf
area (LA) data, but these three traits can hardly characterise whole-plant
responses to the environment individually. CSR strategies reflect
trade-offs among growth, survival and reproduction, at both leaf and
whole-plant levels, thus integrating several functions. We hypothesised
that CSR strategies and the three constituent traits would show
independent plasticity patterns, and that CSR strategies would be more
likely to show adaptive responses, i.e., to fit expected functional
responses to environmental gradients. We compared phenotypic plasticity to
drought in single traits (SLA, LDMC and LA) with the integrated plasticity
of the resulting CSR strategy. The study species was the invasive plant
Mesembryanthemum crystallinum, which is distributed in arid and semiarid
Chile. We found that trait plasticity was rather idiosyncratic and
contrary to what would be expected from a functional adjustment to
drought: LDMC did not change (expected response: increase) and SLA
increased (expected response: decrease). Conversely, plastic responses of
CSR strategy and LA were consistent with functionally adaptive responses
to drought in all populations: S-strategy increased, while C-strategy and
LA decreased. We advocate the use of Grime’s CSR theory as an integrative
approach to further our understanding of adaptive plasticity in plants.