Last month, three environmental groups asked a federal judge for a preliminary injunction restraining the Point Reyes National Seashore from issuing a ranch management plan or long-term ranch leases.

Now in response, the park service, ranchers and the county have defended those actions, describing the critical importance of the ranch plan and the perils—including deleterious environmental effects—of forcing ranchers to rely on one-year leases for the foreseeable future, according to recently filed court documents.

The…