CANCELLED - Fine-scale trait variation of five native forbs along environmental gradients and potential impacts on restoration success

Background/Question/Methods

The need for native seeds and seedlings for ecological restoration is continuously increasing and far exceeds the availability. Given the cost of production and high demand, it is important to maximize the chance of restoration success, which historically has been quite low. One major consideration for seeding failure is potential environmental mismatch between the restoration site and seed place of origin as well as the scale at which native plants are adapted to their local environment. We conducted a study to characterize fine-scale environmental variation (< 10km) and how it related to plant functional traits. We sampled 21 native grassland sites along elevation and insolation gradients and focused on five native forb species: Collinsia parviflora, Phacelia linearis, Erigeron compositus, Geum triflorum, and Gaillardia aristata.At each site, we measured shoot biomass, flower count, specific leaf area and collected seeds to measure seed mass and use in a future reciprocal transplant study. To assess how these variables change with environmental conditions, we also measured gravimetric water content, soil temperature and soil nutrient concentrations.

Results/Conclusions

Geum triflorum showed no significant variation along environmental gradients. Erigeron compositus plants produced larger seeds at higher elevations (p < 0.001, r2 = 0.73). Collinsia parviflora plants produced more flowers with increased soil pH and elevation (p < 0.001), while Phacelia linearis produced more flowers with increased nitrate availability and insolation (p < 0.01). Gaillardia aristata had thinner, higher surface area leaves at the low elevation and low insolation sites (p < 0.01). We found that soil moisture differed ten-fold as did nitrate availability, and maximum soil temperature differed nearly two-fold. We also found evidence that across species, specific leaf area and insolation impact fitness by altering flower number (p < 0.001 and p = 0.02, respectively). We show that species specific trait variation is present along our focal environmental gradients. Determining how these trait differences impact relative fitness will provide valuable insight into environment matching for seed collections and potentially increase restoration success.