15. Using Remotely Sensed Soil Conductivity to Monitor Restoration Activities on Vernal Pools, Northern Great Basin, USA

The sagebrush-steppe of the northern Great Basin, USA, receives 120–500 mm of precipitation per year. Clay horizon formation in these semiarid/arid Pleistocene-lake landscapes allows development of seasonal wetlands (vernal pools) that are recognized critical habitat for several native animal species. Most pools were dug out to create livestock water holes in the early and mid-1900s. Restoration efforts are underway to restore these ecosystems. This study was undertaken to evaluate the pre- and post-restoration hydrology of several regraded vernal pools. Five total sites, one undisturbed and four dugouts, were mapped for apparent electrical conductivity (EC_a) using electromagnetic induction to evaluate hydrologic flow patterns. Two sites were subsequently regraded to fill in dugouts and redistribute excavated piles. EC_a for the restored sites was remeasured 1 year later. EC_a patterns of the dugout pools indicate that the hydrology is directed toward the low areas concentrating soluble salts in the dugout through evaporation. Patterns of the undisturbed site suggest a broader distribution of water and salts. Conductivity patterns of post-restoration show a marked difference in conductivity with a broadening out of the high-concentration area and a decreased difference between the former dugout area and surrounding area. The pattern after 1 year of hydrologic activity suggests that regrading allows the water to spread across a larger area and begins to develop hydrologic patterns similar to undisturbed pools, suggesting potential to restore desired ecological function. Results of this study will refine understanding of vernal pool hydrology and ecology for the region.