Implications of plant functional traits and drought survival strategies for ecological restoration

Abstract

Restoration of degraded grasslands through active revegetation often involves re‐establishing 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 trade‐off has seldom been studied among populations of herbaceous species. 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. 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. 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. Synthesis and applications. Our study provides evidence of an intraspecific trade‐off 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.

Nonlinear drought plasticity reveals intraspecific diversity in a dominant grass species

“…In agreement with Avolio and Smith (2013c), we found that drought selected genotypes G2 S and G11 S were more plastic in root:shoot allocation (although directionally opposite), which follows patterns of selection under drought in other species (Nicotra et al., 2010). G11 S in particular dedicated more resources to thick roots with greater RDMC, greater RDMC plasticity and lower specific root length consistent with tolerance phenotypes in other grasses (Balachowski & Volaire, 2018; Bristiel et al., 2019; de Vries et al., 2016). Overall differences between G2 S and G11 S raise the somewhat obvious but important insight of no single drought resistant phenotype.…”

Drought‐Net rainfall shelters did not cause nondrought effects on photosynthesis for California central coast plants

“…We utilized species from different families that are common in central coastal California and represent different life forms and combinations of traits: a grass species Elymus glaucus , a long‐lived perennial herbaceous forb E. latifolium , a semiwoody subshrub M. aurantiacus , and the woody shrub M. californica . Little is known of the photosynthetic physiology of these species, although there appear to be trade‐offs between resource acquisition and drought for E. glaucus (Balachowski & Volaire, ). Some life history trade‐offs might appear minor but cause important interactions with drought (Shriver, ).…”

Local adaptation to precipitation in the perennial grass Elymus elymoides: Trade‐offs between growth and drought resistance traits

“…Weaker relationships among grown ecotypes could also be due to maternal effects related to the agronomic environments in which seeds were produced rather than to home climate. Previous studies of perennial grass ecotypes across latitudinal gradients have similarly found trade‐offs between growth potential and drought resistance or drought resistance traits, including leaf width, WUE, leaf π o , and regrowth following drought (Aspinwall et al., 2013; Balachowski & Volaire, 2018; Bristiel et al., 2018; Bushey, 2017). Together with these studies, our results for leaf size and π o suggest that intraspecific growth versus drought resistance trade‐offs may involve a variety of drought resistance traits in perennial grasses.…”

“…Trade‐offs between growth and drought resistance are strong at broad taxonomic scales (Brodribb et al., 2007; Reich, 2014; Sack et al., 2013), but have also been observed within species (Balachowski & Volaire, 2018; Isaac‐Renton et al., 2018; Montwe et al., 2016). In E. elymoides , we found that more productive ecotypes had larger individual leaves and higher leaf π o , traits associated with lower dehydration tolerance (Bartlett, et al., 2012; Craine et al., 2013; Scoffoni et al., 2011).…”