PS 32-199 - Forecasting restoration potential from seed: Predictions over large spatial extents

Abstract: Restoration ecology has the potential to have profound impacts on ameliorating the impacts of anthropogenic change, however, to achieve restoration’s full potential, significant advances in predictive power must be made. We aim to address this issue by forecasting a foundational species population dynamics over a large spatial scale. Big sagebrush is a foundational species, that historically dominated over 60 million hectares of land across the western United States, but now occupies approximately less than 50% of its historic range due to invasive annual grasses and altered fire regimes. In an attempt to prevent a state shift from native shrublands to invasive annual grasslands, land managers have executed large efforts to restore burned sagebrush sites, seeding millions of acres in the Great Basin after wildfire. However, the extent to which these restoration efforts are successful is highly variable, particularly in low-elevation locations. Probabilistic forecasts of restoration potential after a fire could be useful in allocating limited land management resources to a myriad of projects. Here, we use structured population models fit within a Bayesian hierarchical framework to forecast sagebrush recovery at sites across the Great Basin. Models we developed using data from 597 burned, seeded sites across the Great Basin, and forecasts were validated using independently collected out-of-sample data. Preliminary results show models predict in-sample data with higher accuracy than out-of-sample validation data. However, most of the variation is captured by site-level random effects, indicating a greater challenge to predict accurate population dynamics at new locations. Model outputs have the potential to provide useful estimates of the probability of time it will take for populations to return to pre-fire levels, which can be harnessed by land management agencies to make decisions regarding resource allocation to restoration projects.