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The Candidate Conservation Agreement is closely related to the "Safe Harbor" agreement, the main difference is that the Candidate Conservation Agreements With Assurances(CCA) are meant to protect unlisted species by providing incentives to private landowners and land managing agencies to restore, enhance or maintain habitat of unlisted species which are declining and have the potential to become threatened or endangered if critical habitat is not protected. The FWS will then assure that if, in the future the unlisted species becomes listed, the landowner will not be required to do more than already agreed upon in the CCA.

How does a CCA impact unlisted species?
enhance or maintain habitat of unlisted species which are declining and have the potential to become threatened or endangered