California Native Plant Society Conservation Conference, 2015

In California’s Central Valley, 98% of native grasslands have been destroyed or degraded due to weed invasion, farming, development, and habitat fragmentation. Grassland restoration is often assumed to provide a host of ecosystem services, including improved wildlife habitat, and therefore should result in higher wildlife abundance and diversity relative to unrestored and invaded grasslands. We compared relative wildlife utilization at paired restored and unrestored (control) grasslands at four locations in Yolo and Sacramento counties using live and camera traps, snake boards, and observational surveys in the spring and summer of 2014. Restored sites were planted with native perennial grasses 10-20 years ago but are heavily invaded with Mediterranean annual grasses and forbs. Control sites contained similar non-native plant assemblages but did not have any native grass cover. In general, mouse, vole, and snake utilization was higher at control relative to restored sites in both spring and summer. Summer raptor surveys revealed greater species diversity, foraging time, and attack rates at control sites as well, likely in response to greater rodent abundance. Within sites, species-specific responses were related to vegetative cover and percent bare ground. For example, Peromyscus maniculatus (deer mouse, Cricetidae) was associated with high bare ground and low vertical cover, regardless of site type (control/restored). Results from continued seasonal monitoring through winter 2016 may aid in clarifying goals and methods of restoration, but these current results suggest that restoring native California grasslands may not increase wildlife utilization, suggesting a more nuanced approach is required for the restoration of biodiversity.