Painted signs began appearing along Sir Francis Drake Boulevard in Inverness this month: “No poison in our watershed.”

Then came an online petition, which, as of Wednesday morning, has gathered more than 1,100 signatures. And, last Sunday, at the annual Western Weekend parade, a man dressed as a sea otter sauntered down Main Street, lofting a sign emblazoned with “No Roundup.”

The alarm was triggered by a California State Parks wildfire-mitigation effort that could allow…