Three eco-physiological strategies of response to drought maintain the form and function of a tropical montane grassland

1. Ecologists seek a general scheme to classify the diversity of plant
responses to environmental factors into a few strategies (e.g. competitor
-C, stress-tolerant -S, ruderal-R), while plant physiologists seek a
mechanistic scheme to explain such different responses (e.g. tolerance,
escape, avoidance). So far, few attempts have been made to combine both
perspectives into plant eco-physiological strategies. Moreover, the
relative contribution of different strategies to maintain both community
structure and ecosystem functioning during drought has rarely been
assessed. This limits our capacity to predict how extreme events caused by
climate change will affect plant communities. 2. Here, we present an
integrated framework to identify plant eco-physiological strategies and to
estimate their contribution to community originality (diversity of
trait-combinations), dominance (species relative frequency), and ecosystem
functioning (productivity and evapotranspiration). 3. We applied this
framework in a tropical montane grassland and found three co-occurring
eco-physiological strategies in this community (S-tolerance/avoidance,
CS-escape/tolerance and CR-escape/avoidance). While CS-species contributed
more to dominance and functionality, CR- and S-species contributed more to
originality. Therefore, all three strategies were important to support the
grassland form and function. Synthesis: Plants exhibit different
strategies, as well as different contributions to community and ecosystem
attributes. We developed an integrated approach to both identify
strategies and estimate their relative contribution. Thereby, as droughts
intensify, we can better predict which plants are more likely to be lost
and how their loss will impact the communities and ecosystem where they
occur. This knowledge is necessary for specifying conservation priorities
and for developing more efficient conservation practices.