To protect and administer more effectively the publicly owned lands within certain parts of the area described in section 577 of this title, and to accomplish certain public purposes explicit and implicit in sections 577a and 577b of this title, the Secretary of Agriculture is authorized and directed to acquire any lands or interest in lands, and appurtenances thereto, situated within the area described in section 577d of this title, where in his opinion development or exploitation, or the potentialities for development or exploitation, impair or threaten to impair the unique qualities and natural features of the remaining wilderness canoe country.