Annual and Perennial Grasslands

Grasslands are a vital part of the region’s ecosystems, providing habitat for multitudes of different plant and animal species. However, California’s grasslands have undergone one of the most dramatic shifts worldwide, with native grasslands—once dominated by diverse perennial bunchgrasses and forbs—largely replaced by non-native annual grasses. Today, only fragments of native grassland remain.

This assessment looked at non-native annual and native perennial grasslands separately to better understand differences in their ecological health. Unfortunately, many past surveys did not distinguish between these grassland types, limiting confidence in these assessments. However, based on what is known, the overall extent of grasslands across the EHA Study Area is in relatively good condition; however, the quality of native perennial grasslands is concerning. Key metrics in the Central EHA Study Area such as native forb richness, native grass cover, and residual dry matter are of significant concern, however native forb cover remains in good condition. Much less is known about the conditions or trends of perennial grasslands in the Coastal EHA Study Area. Non-native, annual grasslands in both study areas are likewise in a condition of significant concern for native forb cover and richness.

To improve management, more detailed monitoring is needed that tracks perennial grasslands separately. Non-native annual grasslands can benefit from carefully managed disturbance, such as grazing, to maintain plant diversity, while native perennial grasslands require tailored conservation and monitoring to ensure their survival and recovery.