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

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-20171. 通过主动植被恢复手段修复退化草地，通常需要重建本土禾草种群，而这些禾草必须抵御日益加剧的干旱胁迫，才能在初始定植后持续存活。对于多年生植物而言，更强的脱水耐受性往往会伴随更保守的生长策略，但这种权衡关系在草本植物种群间的研究却鲜有报道。 2. 我们以产自加利福尼亚地中海气候区的多年生禾草——蓝偃麦草（Elymus glaucus）的4个种群为研究对象，测定了非水分限制条件下的季节生长动态、叶片与根系功能性状，并观测了其在重度干旱后的恢复情况。我们提出假说：来自更严酷生境的种群，其脱水耐受性更强、更易进入夏季休眠，且生长策略更保守。 3. 研究发现，脱水耐受性与夏季休眠均与更保守的资源利用策略相关，具体表现为更低的生产力、更小的比叶面积（Specific Leaf Area）与比根长（Specific Root Length），以及更早的生殖物候期。 4. 多变量性状变异与生长季及夏季的水分可获得性显著相关，而更强的脱水耐受性与夏季休眠则与夏季气候性水分亏缺的加剧呈正相关。 5. 研究总结与应用启示：本研究证实了脱水耐受性与快速资源获取能力之间存在种内权衡关系。我们讨论了这一发现的生态学意义：即具备优异干旱存活能力的恢复种群，其竞争能力可能较弱；同时建议开展进一步研究，以优化植物材料选择方案与草地管理实践。2017年6月26日