Rehabilitasi Hutan Mangrove di Kawasan Pesisir Desa Purworejo, Pasir Sakti, Lampung Timur, Sumatera

Abstract

Kerusakan hutan mangrove di pesisir Desa Purworejo, Kecamatan Pasir Sakti, Lampung Timur terjadi akibat penurunan fungsi hidrologis yang menyebabkan adanya genangan permanen serta peningkatan kadar logam berat di tanah. Kondisi ini menurunkan daya dukung ekosistem, sehingga diperlukan upaya rehabilitasi berbasis kesesuaian biofisik untuk memulihkan fungsi ekologis mangrove. Penelitian ini bertujuan menentukan kawasan potensial untuk direhabilitasi, menganalisis kondisi biofisik lingkungan, serta menilai kesesuaian jenis mangrove dan pendekatan rehabilitasi yang tepat di kawasan mangrove Desa Purworejo. Penelitian dilaksanakan pada Februari–Agustus 2025 menggunakan pendekatan analisis vegetasi, fauna, kualitas tanah, air, oseanografi, dan iklim. Pemetaan dilakukan melalui penginderaan jauh dengan metode Normalized Difference Vegetation Index (NDVI) untuk menentukan area dengan kerapatan tajuk rendah sebagai prioritas rehabilitasi. Pengumpulan data lapangan meliputi analisis vegetasi pada tiga tingkat pertumbuhan, identifikasi fauna potensial sebagai hama, serta pengujian sifat fisik-kimia tanah dan air. Hasil penelitian menunjukkan bahwa area berpotensi rehabilitasi didominasi oleh lahan terbuka dengan gangguan hidrologis dan tekstur tanah lempung berdebu, dengan salinitas air sebesar 24,7 ppt dan tanah 5,9 ppt. Terdapat genangan permanen di lokasi penelitian, sehingga diperlukan perbaikan hidrologi berbasis Ecological Mangrove Rehabilitation (EMR) melalui pembukaan saluran alami untuk mengembalikan sirkulasi air pasang surut. Jenis yang direkomendasikan adalah Rhizophora mucronata, Rhizophora apiculata, Rhizophora stylosa, Avicennia marina, dan Avicennia alba, karena memiliki toleransi terhadap waktu genangan yang panjang, serta suplai benih dari sekitar lokasi rehabilitasi yang melimpah. Sistem akar tunjang pada Rhizophora sp. juga mampu menstabilkan substrat berfraksi debu dan menahan erosi, sedangkan akar napas Avicennia sp. mendukung adaptasi terhadap kadar oksigen rendah dan meningkatkan sirkulasi udara dalam tanah. Teknik rehabilitasi yang sesuai meliputi perbaikan hidrologi disertai pendekatan suksesi alami melalui penyebaran propagul dengan bantuan manusia. Apabila perbaikan hidrologi tidak dilakukan, alternatif lainnya adalah penanaman di sepanjang tepi sungai hingga 30 m dari badan air agar tetap terjangkau pasang surut harian. Pola tanam berkelompok (cluster planting) dinilai paling efektif untuk meningkatkan perlindungan bibit, mengurangi erosi, dan mempercepat terbentuknya struktur hutan yang stabil.

Degradation of the mangrove ecosystem along the coastal area of Purworejo Village, Pasir Sakti Subdistrict, East Lampung, has occurred due to the decline in hydrological function, resulting in permanent waterlogging and elevated levels of heavy metals in the soil. These conditions have reduced the ecological carrying capacity of the area, thereby necessitating biophysical-based rehabilitation efforts to restore the ecological functions of mangroves. This study aims to determine areas with rehabilitation potential, analyze the biophysical environmental conditions, and determine suitable mangrove species and appropriate rehabilitation approaches in the mangrove area of Purworejo Village. The research was conducted from February to August 2025, employing analyses of vegetation, fauna, soil, water quality, oceanographic, and climatic parameters. Spatial mapping was performed using the Normalized Difference Vegetation Index (NDVI) method to identify areas with low canopy density as rehabilitation priorities. Field data collection included vegetation analysis across three growth stages, identification of potential pest fauna, and laboratory testing of the physical and chemical properties of soil and water. The results indicated that the potential rehabilitation area is dominated by open land with hydrological disturbance and a silty loam texture, with water salinity of 24.7 ppt and soil salinity of 5.9 ppt. Permanent inundation was observed at the site, suggesting the need for hydrological restoration through the Ecological Mangrove Rehabilitation (EMR) approach by reopening natural tidal channels to restore water circulation. The recommended mangrove species are R. mucronata, R. apiculata, R. stylosa, Avicennia marina, and Avicennia alba, which exhibit high tolerance to prolonged inundation and benefit from abundant seed supply from surrounding stands. The stilt root system of Rhizophora sp. contributes to stabilizing silty substrates and preventing erosion, while the pneumatophores of Avicennia sp. enhance adaptation to low-oxygen conditions by improving aeration within the soil. The appropriate rehabilitation techniques include hydrological improvement combined with natural succession through human-assisted propagule dispersal. In cases where hydrological repair cannot be immediately implemented, an alternative method is planting mangroves along riverbanks up to 30 meters from the waterbody to ensure tidal inundation. The cluster planting pattern is considered the most effective strategy to enhance seedling protection, reduce erosion, and accelerate the formation of a stable mangrove forest structure.