Struktur Komunitas Estimasi Simpanan Karbon Tegakan Mangrove Di Pesisir Sungai Sambas Besar, Kecamatan Tekarang, Kabupaten Sambas: Community Structure and Estimation of Mangrove Stand Carbon Stock on the Coast of the Sambas Besar River, Tekarang Subdistrict, Sambas Regency - Haq, Izhar Amirul; Urabi, Debby; Jordi, Jordi; Audina, Mia; Junaidi, Junaidi (Fakultas Kehutanan Universitas Jambi, 2025)
ABSTRACT Mangrove ecosystems play an important role in coastal protection, habitat provision, and carbon storage (blue carbon). This study aimed to analyze mangrove community structure and to estimate carbon stocks and CO₂ sequestration along the Sambas Besar River, Tekarang Subdistrict, Sambas Regency. The research was conducted in September 2025 using an exploratory approach with purposive sampling near a bridge construction area. Vegetation data were collected using line transects and quadrats of 10×10 m, 5×5 m, and 2×2 m according to growth stages. Community structure was assessed using density, frequency, dominance, and the Importance Value Index (IVI). Biomass was estimated using allometric equations for Sonneratia caseolaris, Nypa fruticans, and a general mangrove model. Carbon stocks were calculated using a carbon fraction of 0.47, and CO₂ sequestration was estimated based on molecular ratios. Three mangrove species were identified (S. caseolaris, N. fruticans, and Acanthus ilicifolius), with S. caseolaris as the dominant species (mean IVI 226.026 at the tree level and 300 at the sapling level). The average stand biomass was 35.355 t/ha, mean carbon stock was 14.266 t/ha, and estimated CO₂ sequestration reached 111.302 t/ha. Measured water parameters (pH ≈ 6.9; DO ≈ 5.4 mg/L; temperature ≈ 30 °C; salinity ≈ 12 ppt) supported mangrove ecosystem functions. These results confirm the contribution of mangrove stands to carbon storage and emission mitigation and emphasize the need for conservation management, periodic monitoring, and targeted rehabilitation. Keywords: biomass, community structure, Sambas River, stand carbon. ABSTRAK Ekosistem mangrove berperan penting dalam proteksi pesisir, habitat, dan penyimpanan karbon (blue carbon). Pemahaman mengenai struktur komunitas dan estimasi simpanan karbon tegakan diperlukan untuk perencanaan konservasi dan mitigasi iklim. Penelitian ini bertujuan mengetahui struktur komunitas dan mengestimasi simpanan karbon serta serapan CO₂ pada tegakan mangrove di pesisir Sungai Sambas Besar, Kecamatan Tekarang, Kabupaten Sambas. Penelitian dilaksanakan pada Bulan September 2025 dengan pendekatan eksplorasi dan pemilihan stasiun purposive di sekitar pembangunan jembatan. Data vegetasi dikumpulkan melalui transek garis dan kuadran 10×10 m, 5×5 m, dan 2×2 m sesuai kategori pertumbuhan. Analisis meliputi kerapatan, frekuensi, dominansi, dan Indeks Nilai Penting (INP). Biomassa tegakan diperkirakan menggunakan persamaan allometrik spesifik untuk S. caseolaris, N. fruticans, dan model umum mangrove. Simpanan karbon dihitung dengan faktor fraksi karbon 0,47; serapan CO₂ dihitung berdasarkan rasio molekuler CO₂ terhadap C. Tiga spesies teridentifikasi yaitu S. caseolaris, N. fruticans, dan A. ilicifolius. S. caseolaris sebagai spesies yang dominan (INP rata-rata 226,026 pada tingkat pohon; 300 pada tingkat pancang). Rata-rata biomassa tegakan 35,355 ton/ha, simpanan karbon 14,266 ton/ha, dan estimasi serapan CO₂ 111,302 ton/ha. Parameter perairan yang telah diukur (pH ≈ 6,9; DO ≈ 5,4 mg/L; suhu ≈ 30 °C; salinitas ≈ 12 ppt) memenuhi standar yang relevan serta mendukung fungsi ekosistem mangrove. Hasil menegaskan kontribusi tegakan mangrove terhadap stok karbon dan mitigasi emisi serta menuntut pengelolaan konservasi, monitoring berkala, dan rehabilitasi terarah. Kata kunci: biomassa, karbon tegakan, struktur komunitas, Sungai Sambas.