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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #362532

Research Project: Adaptive Rangeland Management of Livestock Grazing, Disturbance, and Climatic Variation

Location: Livestock and Range Research Laboratory

Title: Increased soil temperature and decreased precipitation during early plant life stages constrain grass seedling recruitment in cold desert restoration

Author
item JAMES, JEREMY - University Of California
item Sheley, Roger
item LEGER, ELIZABETH - University Of Nevada
item ADLER, PETER - Utah State University
item Hardegree, Stuart
item GORNISH, ELIZABETH - University Of Arizona
item Rinella, Matthew - Matt

Submitted to: Journal of Applied Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2019
Publication Date: N/A
Citation: N/A

Interpretive Summary: 1. Seed-based restoration is one of the most difficult challenges dryland restoration practitioners face. Identifying environmental conditions that drive variation in seed and seedling mortality across similar restoration efforts could increase understanding of when and where restoration outcomes are likely to be favorable and identify new tools and strategies to improve outcomes. 2. We asked how variation in a suite of environmental predictors influenced germination, emergence, seedling establishment, and juvenile survival of four commonly sown perennial grass species across 33 seeding experiments distributed over a ~160,000-km2 area of the Great Basin, a cold desert system in western United States. 3. Across experiments, we observed wide variation in survival rates among all four life history stages and wide variation in environmental conditions experienced by plants at each stage. For all species, higher precipitation the first 30 days following seeding increased germination. Conversely, higher soil temperatures over this same period decreased germination and emergence and was associated with a substantial portion of the variation in germination and emergence probabilities observed across seeding experiments. 4. Within the range of precipitation variation observed, we were unable to detect a significant relationship between seedling survival the first growing season and cumulative precipitation the first year, precipitation during the first spring growing season, or annual climatic water deficit (CWD) the first year. Alternatively, a higher CWD the second growing season reduced seedling survival over that period. 5. Synthesis and application. Our results show warm temperatures negatively impact grass seedling recruitment through multiple pathways. Our results can be combined with seasonal and subseasonal temperature forecasts to improve restoration decision-making. These results also suggest climate warming will make restoration even more difficult, with our model estimates suggesting the 2°C increase in temperature expected in the Great Basin over the coming decades will decease germination and emergence by about 30%. Lastly, while our inductive approach provided insight into short-term drivers of mortality it did not provide accurate prediction of longer-term survival. This suggests a need to develop deductive approaches for predicting long-term restoration outcomes.

Technical Abstract: 1. Seed-based restoration is one of the most difficult challenges dryland restoration practitioners face. Identifying environmental conditions that drive variation in seed and seedling mortality across similar restoration efforts could increase understanding of when and where restoration outcomes are likely to be favorable and identify new tools and strategies to improve outcomes. 2. We asked how variation in a suite of environmental predictors influenced germination, emergence, seedling establishment, and juvenile survival of four commonly sown perennial grass species across 33 seeding experiments distributed over a ~160,000-km2 area of the Great Basin, a cold desert system in western United States. 3. Across experiments, we observed wide variation in survival rates among all four life history stages and wide variation in environmental conditions experienced by plants at each stage. For all species, higher precipitation the first 30 days following seeding increased germination. Conversely, higher soil temperatures over this same period decreased germination and emergence and was associated with a substantial portion of the variation in germination and emergence probabilities observed across seeding experiments. 4. Within the range of precipitation variation observed, we were unable to detect a significant relationship between seedling survival the first growing season and cumulative precipitation the first year, precipitation during the first spring growing season, or annual climatic water deficit (CWD) the first year. Alternatively, a higher CWD the second growing season reduced seedling survival over that period. 5. Synthesis and application. Our results show warm temperatures negatively impact grass seedling recruitment through multiple pathways. Our results can be combined with seasonal and subseasonal temperature forecasts to improve restoration decision-making. These results also suggest climate warming will make restoration even more difficult, with our model estimates suggesting the 2°C increase in temperature expected in the Great Basin over the coming decades will decease germination and emergence by about 30%. Lastly, while our inductive approach provided insight into short-term drivers of mortality it did not provide accurate prediction of longer-term survival. This suggests a need to develop deductive approaches for predicting long-term restoration outcomes.