Wed, Aug 17, 2022: 10:40 AM-11:00 AM
520F
Background/Question/MethodsThe sagebrush steppe is one of the most ecologically imperiled landscapes in North America. The exotic annual grass invasion and the associated large-scale wildfires are contributing to rapid landscape‐level conversion from native perennial plant communities to highly degraded annual grass-dominated systems. While seeding efforts to re-establish native plant communities have been ongoing, success has been limited, in part due to competition with invasive annuals and spatiotemporal variability in site conditions. Pre-emergent herbicides, like imazapic, can be an effective tool in reducing invasive annual grass cover. However, herbicide application also negatively impacts seeded species; as a result, restoration seedings are typically carried out one or more years after herbicide treatment. Herbicide protection (HP) seed technologies may offer an opportunity to simultaneously apply herbicide and seed desired species, reducing invasive annual grass competition on seeded natives during the crucial first growing season. To improve restoration outcomes, our team used an adaptive experimental design to evaluate multiple HP technologies (carbon slurry, extruded pellets, carbon coating) for important native bunchgrass and sagebrush species across a spatiotemporally diverse array of sites over several planting years.
Results/ConclusionsOverall, our approach allowed us to evaluate a broad range of HP technologies, accounting for the variation in conditions across sites and years. Our findings suggest that HP seed technologies show some promise in improving seeding success in the presence of herbicide during early plant development, but longer-term outcomes will need to be evaluated further. Additionally, despite the spatiotemporal variation in our study locations, a multi-year drought was a significant barrier to seedling establishment. This suggests that impacts of long-term drought should be increasingly considered in experimental approaches that depend on adaptive learning and in dryland restoration efforts more broadly. Finally, developing methods that help address or bet hedge against multiple restoration barriers will require additional research.
Results/ConclusionsOverall, our approach allowed us to evaluate a broad range of HP technologies, accounting for the variation in conditions across sites and years. Our findings suggest that HP seed technologies show some promise in improving seeding success in the presence of herbicide during early plant development, but longer-term outcomes will need to be evaluated further. Additionally, despite the spatiotemporal variation in our study locations, a multi-year drought was a significant barrier to seedling establishment. This suggests that impacts of long-term drought should be increasingly considered in experimental approaches that depend on adaptive learning and in dryland restoration efforts more broadly. Finally, developing methods that help address or bet hedge against multiple restoration barriers will require additional research.