Sheep Grazing as a Tool for Vernal Pool Stewardship

View the project final report

• 2006 annual report
• 2007 annual report

Commodities

• Animals: sheep

Practices

• Animal Production: range improvement
• Education and Training: demonstration
• Natural Resources/Environment: biodiversity, habitat enhancement, wetlands
• Pest Management: weed ecology
• Production Systems: agroecosystems, holistic management
• Sustainable Communities: partnerships, urban/rural integration

Vernal pools are temporary wetlands that once occurred throughout California grasslands and provided habitat for many rare and endemic organisms. Today, less than 10% of pool habitat remains, and native pool species across California are in decline. Anecdotal evidence indicates that pools on active ranchlands often have healthier native plant populations than do those from which livestock grazing was removed in recent decades. Land managers in Sonoma County and elsewhere in California are poised to reintroduce managed grazing to pools in hopes of encouraging natives, but are hesitating for lack of careful research on which to base their management plans. To address this gap in knowledge, we have begun a sheep-grazing experiment in collaboration with local ranchers. At a Sonoma County site with vernal pools, half of each pool has been fenced to exclude grazing; the other halves are unfenced and readily accessible to sheep. We will monitor and compare the hydrology and vegetation of grazed and ungrazed plots. After collecting and analyzing our data, we plan to host a field workshop at the study site to share our results with local ranchers and land managers. We also aim to publish our results in a peer-reviewed scientific journal focusing on applied ecology. We predict that grazing will increase native plant cover and control exotic plants. If so, valuable opportunities are likely to open up for ranchers in Sonoma County, where rising land values currently limit the economic feasibility of ranching, despite strong public interest in maintaining the county’s rural heritage.

• Investigate the value of sheep grazing as a tool for managing vernal pools: establish a grazing experiment in collaboration with local rancher and City of Santa Rosa, using a set of pools and fenced exclosures. determine plant community composition (percent cover of each species, species richness) in 8 plots per pool. sample residual dry matter to quantify grazing intensity. repeat grazing and monitoring annually through summer 2008. analyze data with appropriate statistical tests. fall 2006: present preliminary results at the Bay Area Grasslands Management Conference spring 2008: host a field workshop on the use of livestock grazing on vernal pools. summer 2008: complete and submit a manuscript describing our research to a peer-reviewed scientific journal focusing on applied ecology.