The Board of Supervisors on Tuesday approved a $537,000 grant to the Marin Agricultural Land Trust to help fund the purchase of a conservation easement near Tomales that will extend a continuous belt of 19 protected ranches. The development rights to the Thacher Ranch will total about $1.8 million dollars, with the difference funded by other grants and private donations. The 623-acre property has been in one family since 1954, but it is now undergoing a generational transfer. Without an easement, the family could face pressure to subdivide, said county planner Craig Richardson. The property is not only agriculturally valuable, but also houses a tributary to Walker Creek that provides habitat to red-legged frogs and steelhead trout. Creating and enlarging these continuous blocks strengthens both agricultural sustainability and ecological networks for wildlife, said Jamison Watts, the executive director of MALT. Supervisor Steve Kinsey applauded the use of Measure A funds for the project: “This is a real-life, put-your-money-where-your-mouth-is expression of our board’s commitment to agriculture,” he said. The grant is the first sourced from Measure A’s farmland preservation program, which sets aside 20 percent of the measure’s tax revenue for matching grants to support agriculture, primarily through purchasing new easements.