Cal. Fish and Game Code § 1021

(a) The department may take feasible actions to conserve monarch butterflies and the unique habitats they depend upon for successful migration. These actions may include, but are not limited to, habitat restoration on department lands, education programs, and voluntary agreements with private landowners. (b) The department may partner with federal agencies, nonprofit organizations, academic programs, private landowners, and other entities that undertake actions to conserve monarch butterflies and aid their successful migration, including the Monarch Joint Venture. (c) When undertaking actions to conserve monarch butterflies and their habitats pursuant to this section, the department shall use the best available science and consider, as appropriate and feasible, all of the following: (1) Restoring or revegetating monarch caterpillar habitat using regionally or locally appropriate native milkweed species. (2) Restoring or revegetating adult monarch butterfly habitat using regionally or locally appropriate native nectar plant species. (3) Controlling nonnative weed species that threaten native milkweed species, and controlling pests and disease, using current best management practices consistent with integrated pest management principles that pose low risk to monarch butterflies and their habitat. (4) Incorporating diverse tree species, structures, and arrangements when restoring or establishing winter habitat sites to match monarch butterfly preferences for temperature, light, moisture, wind, and other microclimate characteristics. (5) Increasing the number of partnerships and making the most of partnerships to use residential and institutional landscaped areas, agricultural noncropped lands, transportation corridors, and conservation easements to create, restore, or enhance monarch butterfly habitat. (d) The fact that a project applicant or landowner does not enter into a voluntary agreement to protect monarch butterflies shall not be grounds for denying a permit or agreement or requiring additional mitigation beyond what would be required to mitigate project impacts under other applicable laws, including, but not limited to, the California Environmental Quality Act (Division 13 (commencing with Section 21000) of the Public Resources Code).