<![CDATA[Abstract. The research aim was to study the impact of land use change on ecosystem values of mangrove in Seruway, Aceh Tamiang district. To identify the important index value at the level of trees, the measurement was done by creating plot transects, plot A covering areas of 20 m x 20 m, plot B covering areas of 5 m x 5 m and plot C covering areas of 2 m x 2 m. The calculation of economic values was measured through Direct Use Value, Indirect Use Value and Option Value by using Benefit Transfer, likewise the total economic values was measured by using contingent valuation method. The area of mangrove forests in the research site as large as 573.06 ha (19.26 %) compared to palm oil plantation as large as 1940.95 ha (62.25 %). The reduction in mangrove areas causing the ecological damages, such as : the wells water could not be maximally used by peoples due to the bad quality (bad smell), the decrease of fisheries harvest and the reduction of diversity of fish, the extinction of several fish species which has high economic values, the occurrence of abrasion and the loss of important species of mangrove. Economically, it clearly showed that the loss of value of the direct benefits, indirect benefit sand benefit options was occurred, as consequences the Total Economic Value lost from the mangroves was Rp. 11,593,728,000 /year. Abstrak. Penelitian ini bertujuan untuk mengkaji dampak alih fungsi lahan terhadap nilai ekosistem mangrove di Kecamatan Seruway Kabupaten Aceh Tamiang. Untuk mengetahui Indeks Nilai Penting pada tingkat pohon, maka dilakukan pengukuran dengan membuat petakan transek untuk plot A seluas 20 x 20 m, plot B seluas 5 x 5 m dan plot C seluas 2 x 2 m. Perhitungan nilai ekonomi diukur melalui Direct Use Value, Indirect Use Value dan Option Value dengan menggunakan Benefit transfer sementara nilai total ekonomi menggunakan metode penilaian kontingensi. Luas kawasan hutan mangrove di lokasi penelitian sebesar 573,06 ha (19,26%) hal ini berbanding jauh dengan luas perkebunan sawit sebesar 1.940,95 ha (62,25%) artinya lebih dari 50 % penggunaan lahan. Berkurangnya luasan mangrove ini berakibat pada kerusakan ekologi seperti ; air sumur warga yang tidak dapat dimanfaatkan secara maksimal (berbau), burkurangnya hasil tangkapan dan jenis perikanan, langka dan punahnya beberapa spesies yang bernilai ekonomi, terjadinya abrasi dan hilangnya jenis tumbuhan mangrove penting. Secara ekonomi jelas terlihat kerugian dari nilai manfaat langsung, manfaat tidak langsung dan manfaat pilihan, sehingga nilai Total Economic Value yang akan hilang dari hutan mangrove adalah sebesar Rp. 11.593.728.000,-/tahun.]]>
