Innovative earth-moving restoration has successfully returned wetland function, natural landform, and abundant native species across 190 acres of mounded vernal pool habitat in the Rogue River Valley of southwest Oregon. Led by the Oregon Department of Transportation in collaboration with The Nature Conservancy, the restoration meets compensatory mitigation goals and demonstrates effective methods for recovery of threatened and endangered species: vernal pool fairy shrimp, Cook’s desert parsley, and large-flowered woolly meadowfoam. The project and restoration site, the Whetstone Savanna, exemplify the strength of mitigation banking integrated with local and regional conservation planning.
This report presents the restoration within a context of local vernal pool ecology, natural history, and habitat conservation. Planning and implementation methods, monitoring results, and lessons learned are documented here to provide an example of repeatable success in vernal pool restoration. On the ground work was completed from 2011 – 2019 by a team of ecologists and equipment operators. Advanced mapping tools, adaptive workflows, and precision grading enabled restoration of topography and hydrology damaged by past alterations. Grading was strategically combined with prescribed burning and seeding to restore native plant communities and listed species populations.
Annual monitoring for mitigation performance established a four-year baseline and tracked changes during and after eight years of active restoration. Vernal pool habitat doubled in area, and occupancy by vernal pool fairy shrimp increased to four times the pre-restoration level. Populations of endangered plants numbering in the thousands have established from widespread sowing. Following restoration, native plant abundance more than doubled on uplands and nearly tripled in pools, accompanied by substantial gains in native species diversity and a dramatic reduction in non-native invasive weeds. This type of transformative restoration is needed on other degraded vernal pool sites to achieve effective long-term habitat conservation and lasting species recovery at a landscape scale.
