University of Arizona Tucson, Arizona, United States
Background/Question/Methods Seed-based restoration is a method used in many dryland regions due to the large geographic extent of disturbances in these areas. However, even though seeding is often better than doing nothing at all, many seed-based restoration efforts have less than desired seedling establishment. Low seedling establishment rates are attributed to abiotic and biotic barriers that may occur as a single event, such as a heatwave or high granivore population year (e.g. ants and rodents), or multiple linked and co-occurring events such as a drought and heatwave that trigger higher survival of herbivores like grasshoppers. While we have struggled for decades in attempting to restore ecosystems, the challenges of the past decades will likely intensify due to changes in global environmental conditions making our need to develop novel approaches and technologies to overcome restoration barriers ever more critical. In this talk, I present case studies to highlight some major challenges facing restoration efforts, including extreme weather conditions, and novel approaches we may take to overcome those barriers.
Results/Conclusions I cover a variety of case studies impacted by both abiotic and biotic extremes. Firstly, I describe one of my failed experiments for restoration seeding during the 2020 drought in southwest Arizona. I established plots where I seeded in restoration species. The impacts of a near record drought increased ant forage activity resulting in most of the seed placed on the ground lost in just under a week. Approaches to reduce granivory and protect seeds from extreme conditions could be to use emerging seed enhancement technologies such as seed coatings or seed balls. Second, I describe another experiment impacted by erosion and flooding. Restoration seeds were installed in a flat desert site. In 2021, the area received over 15” of precipitation (about 2.5X the normal amount) and was the wettest monsoon season in 7 years. This led to flooding and sheet erosion burying and/or transporting seeds leading to a 95%+ loss in seed. Approaches to improve restoration project success would be to install structures to arrest soil erosion such as media lunas as well as reserving seed to broadcast over multiple years. Overall, we need to study novel, wholistic approaches to improve restoration under extreme abiotic and biotic events.
