Cal. Rev. & Tax. Code § 423.8

(a) Notwithstanding the acreage requirement specified in subdivision (f) of Section 421, both of the following apply with respect to enrollment in a wildlife habitat contract:
1. (1) Any open-space land that has been restricted as wildlife or endangered species habitat by a political subdivision of the state or entity of state government shall, upon the request of the owner of that land, be enrolled in a wildlife habitat contract with the political subdivision of the state or entity of state government that has so restricted the subject open-space land.
2. (2) Any open-space land that has been restricted as wildlife or endangered species habitat by an agency of the federal government shall, upon the request of the landowner, be enrolled in a wildlife habitat contract with the city or county having jurisdiction over the restricted open-space land.
  For any open-space land eligible for valuation under Section 422.5, 423, 423.3, 423.5, 426, or 435, that has also been enrolled in a wildlife habitat contract pursuant to this section, the controlling value of the land shall, except as otherwise provided in the following sentence, be the lower of the values determined for that land pursuant to those sections or Section 402.1. Other lands enrolled in a wildlife habitat contract pursuant to this section shall be assessed at the value determined as provided in Section 402.1.
(b) In no event shall this section or Section 421 be construed to authorize a political subdivision or any entity of the state or federal government to restrict the otherwise lawful use of property by designating all or part of that property as wildlife habitat or endangered species habitat without the consent of the owner of that property.
(c) It is the intent of the Legislature in adding this section to establish a nonexclusive alternative method of recognizing, for purposes of property taxation, the existence of certain governmental restrictions on the use of property. Neither this section nor Section 402.1 shall be construed or applied to require the existence of a wildlife habitat contract, as described in this section, as a necessary condition for recognizing the effect upon the taxable value of property of any enforceable restriction that is recognized under Section 422, 422.5, or 402.1 and is legally established by statute, regulation, or any action or classification by a governmental entity, for the benefit of wildlife, endangered species, or their habitats.