Résumé
1. Restoration of degraded grasslands through active revegetation often
involves reestablishing populations of native grasses, which must
withstand increasing drought stress to persist beyond initial
establishment.. In perennial species, superior dehydration tolerance is
expected to result in more conservative growth, but this tradeoff has
seldom been studied among populations of herbaceous species. 2. We
measured seasonal growth and foliar and root functional traits under
non-limiting water conditions, followed by recovery after severe drought
in four populations of Elymus glaucus, a perennial grass from California’s
Mediterranean-climate region. We hypothesized that populations from
harsher sites would be more dehydration tolerant, summer dormant, and
resource-conservative. 3. Dehydration tolerance and summer dormancy were
associated with a more conservative strategy (lower productivity, lower
Specific Leaf Area and Specific Root Length), as well as earlier
reproductive phenology. 4. Multivariate trait variation was associated
with water availability in both the growing season and summer, while
greater dehydration tolerance and summer dormancy were associated with
increasing summer climatic water deficit. 5. Synthesis and applications:
Our study provides evidence of an intraspecific tradeoff between
dehydration tolerance and rapid resource acquisition. We discuss the
implication that restored populations with superior drought survival may
therefore be less competitive, and recommend further investigation to
inform plant materials selection protocols and management
practices.26-Jun-2017