Hitting moving restoration targets: Using plant traits and geographic origin to predict population-level climate (CO2 and temperature) responses

Background/Question/Methods

Restoration ecologists are tasked with planning for revegetation efforts under uncertain climatic conditions presented by global changes in temperature, atmospheric CO₂ and precipitation that can greatly alter plant community structure and function. In this study we evaluated inter- and intra-specific (accession-level) variation in climate responses of seven semi-arid steppe species. We hypothesized that growth responses to warming and elevated CO₂ (which can increase soil moisture) would be predictable from temperature and precipitation of origin or climate-relevant traits. To test these hypotheses, we grew 8-10 accessions of each species, collected across a range of precipitation and temperature regimes, in growth chambers under ambient or elevated CO₂and/or temperature. 

Results/Conclusions

Preliminary results indicate that above-ground biomass of most species responded positively to elevated CO₂, warming, or both. Substantial variation in warming and CO₂ responses among accessions, however, was not consistently related to climate of origin. A positive relationship between temperature of origin and temperature response was observed for only one species, the warm-season grass Bouteloua gracilis (R²=0.17). Positive relationships between precipitation of origin and CO₂ responses were observed for only two species, Elymus elymoides (R2=0.31) and Heterotheca villosa (R2=0.37). Based on these results climate of origin may be insufficient to determine the likelihood of that population succeeding under future climates. The variability in additional fitness related traits such as growth potential, leaf and root traits across accessions will be discussed and related to implications for restoration ecology.