Background/Question/Methods Microsite limitation constrains plant re-assembly during restoration, particularly in severely degraded ecosystems where sources of microsites such as remnant perennial vegetation and microtopography are lacking. Microsite creation can increase plant recruitment during seeded restoration, but this is often time-intensive and costly, making it ill-suited for large spatial scales. Unfortunately, the areas in need of restoration are extensive, with over 33 million hectares of rangeland showing moderate degradation or worse in the western U.S. alone. Current seeded restoration methods employed over large spatial scales are imprecise, contributing to a failure rate of >90% for seedling establishment in dryland restoration globally. In this study, we test UAS-based structure for motion photogrammetry as a way to sense microtopography seed microsites. We experimentally created soil depressions to mimic naturally occurring depressions in the soil, and measured soil temperature at the surface and soil moisture in the first 10cm. We broadcast seeded the depressions and controls with a seedmix containing six native species and measured the biomass and seedling density responses to soil depressions. Results/Conclusions We expected soil depressions to collect moisture and provide partial shading, resulting in longer dry-down periods after precipitation and lower temperature at the soil surface. Results support this; created depressions had higher soil moisture compared to the controls, and the difference increased with more precipitation. Soil depressions also had lower average soil surface temperature compared to controls. These findings suggest that microtopographical soil depressions alter abiotic conditions necessary for a seed microsite. Further, these altered abiotic conditions occur at a scale that is detectable remotely using cost-effective structure for motion photogrammetry, offering a method to increase precision of seeding during restoration in a scalable way.
