CNPS Grassland Initiative Update (July 2011)
Jennifer Buck-Diaz
The California Native Plant Society was awarded a Conservation Innovation Grant by the National Resources Conservation Service in 2009 to (1) Categorize variation in grassland types through inventory and analysis, and (2) Develop tools for mapping and monitoring to improve management of grassland resources. The study area focused on San Joaquin Valley and Carrizo Plain habitats which encompass a wide range of herbaceous communities from alkali flats to perennial bunchgrasses. A summary of this project follows. To see the full NRCS CIG report click here, or visit our Reports page to view this and our other mapping and classification reports..
Invasive plant species
Non-native and invasive plant species detected in recent field surveys were analyzed at nine sites within the study area. Control measures and management recommendations are presented for high-risk invasive species. In addition to reducing the invasion of non-native species, the proposed management activities can enhance native plant cover and increase the forage value of rangelands (e.g., by decreasing Bromus diandrus and other non-palatable herbs).
Vegetation mapping and analysis
In the Carrizo Plain, a pilot fine-scale vegetation mapping effort was undertaken through heads-up digitizing across 10,000 acres. The mapping of grassland habitats has proven difficult in the past because the variation in grassland types is typically not visible or interpretable on aerial or satellite imagery. This project utilized quality imagery as well as numerous surveys to inform the delineation of alliance and association-level grassland types with successful results. The mapping includes delineation and attribution by vegetation type, shrub cover, herb cover and site impacts using 2007 1-foot resolution base imagery. An accurate vegetation map provides a baseline, floristic dataset for this region and will allow for detailed assessment, modeling, and management of plant species, vegetation, and wildlife habitat resources.
Along with samples collected under this NRCS grant, hundreds of other existing grassland surveys from related vegetation projects were compiled and analyzed to categorize a large array of data for this region. Field data were analyzed statistically to develop a floristically-based vegetation classification. More than 500 vegetation samples were classified according to the National Vegetation Classification System to the alliance and association level.
Data from the compiled datasets were classified into 16 herbaceous alliances, within which 49 associations were identified. This draft classification defines 4 new herbaceous alliances and 38 new herbaceous associations not previously published in our Manual of California Vegetation. For a list of new vegetation types see our full NRCS rangeland report.
Rangeland monitoring workshop
To publicize these exciting new results, CNPS ecologists offered a two-day rangeland monitoring workshop at the Bakersfield UC Cooperative Extension Office in March 2010. Twenty attendees from public and private agencies came together to learn about sampling and monitoring rangeland vegetation and to better understand the challenges of rangeland management.
On the first day, participants were given an orientation of the CNPS NRCS-CIG project and a thorough description of the protocols used during sampling and classification of Central Valley rangeland vegetation. A local rancher assisted in an afternoon tour describing his management strategies for pastures on the Tejon Ranch at the southern end of the San Joaquin Valley. Botanists assisted students in field identification of both native and non-native rangeland plant species.
The second day of the workshop focused on training participants to sample rangeland vegetation with the CNPS Relevé field sampling protocol. Attendees learned how to collect plot data in addition to practical uses for vegetation monitoring and assessment.
Next steps…
Support for this project will continue across two additional field seasons to further explore seasonal and annual variation in grassland vegetation, especially annual herbs, by allowing us to revisit and re-sample field sites. Visit the CNPS Grasslands page for more information about grasslands in California or contact Jennifer Buck-Diaz at jbuck@cnps.org.