Abstract. Analuddin K, Kadidae LO, Haya LOMY, Septiana A, Sahidin I, Syahrir L, Rahim S, Fajar LOA, Nadaoka K. 2020. Aboveground biomass, productivity and carbon sequestration in Rhizophora stylosa mangrove forest of Southeast Sulawesi, Indonesia. Biodiversitas 21: 1316-1325. This study was aimed at analyzing the trends of aboveground biomass (AGB), productivity and carbon sequestration of Rhizophora stylosa Griff. forest in Rawa Aopa Watumohai National Park (RAWNP), Southeast Sulawesi, Indonesia. The DBH was the best predictor for partial and whole AGB of R. stylosa trees. The mean AGB was 562.76 ton ha-1. The yearly biomass increment of living trees, biomass increment of whole stands, standing dead biomass, and litterfall in R. stylosa forest were estimated as 52.87, 50.09, 2.78 and 12.00 ton ha-1, respectively, while its net primary production was about 64.88 ton ha-1 yr-1 indicating higher mangrove productivity. The total carbon stock in R. stylosa forest was 264.50 ton ha-1, while the annual net carbon budget, carbon gain and carbon input in R. stylosa forest was 23.54, 24.85 and 5.64 ton ha-1. However, the total CO2 stored in R. stylosa forest was 969.83 ton ha-1, while the annual of net CO2 uptake, CO2 gained and CO2 input was 86.33, 91.12 and 20.86 ton ha-1. The higher carbon sequestration and CO2 uptake in R. stylosa forest indicate its significant role in the global carbon accumulation and reducing atmospheric CO2.

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As elsewhere in Indonesia, Local inhabitants in the Pangkajene and Kepulauan (PANGKEP) Regency, Spermonde Archipelago area and along the southwest coast of Sulawesi traditionally regard the coral reefs as their livelihood source. Since human activities as well as natural disturbances posed major threats to the coral reefs, these livelihoods may also be at risk. Currently, no comprehensive information on the status and condition of coral reefs in this area is available for this resource management. We determined the changes of coral reef habitat over a period of 20 years from 1994 to 2014 using a satellite Landsat multi-temporal image substantiated with in-situ measurement data collected in 2014. The spectral value of coral reefs was extracted from multi-temporal Landsat imagery data, while the diffuse attenuation coefficient of water was obtained by using statistical analysis between the ratio of live coral cover and the spectral value of the visible bands. By using the unsupervised classification integrated with the data ground truth, it is stated that there has been a decline in live coral cover over a period of 20 years from 7,716 ha in 1994 to 4,236 ha in 2014, with a degradation rate of 174 ha/yr. Based on the results, the ratio of the coral cover in the coral reef transects varied from the average of 24% for live corals to 96% for coral rubbles, implying the degraded status of coral reefs in the study area.

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Studi tentang lamun telah dilakukan di perairan Desa Tanjung Tiram. Penelitian ini bertujuan untuk menentukan sebaran, tutupan, dan habitat lamun menggunakan citra LANDSAT 8 OLI dan Sentinel 2A. Metode penelitian yang digunakan adalah perbandingan klasifikasi dua citra yang dikombinasikan dengan data lapangan. Citra yang digunakan telah dikoreksi menggunakan algoritma Depth Invariant Index (DII) untuk menghilangkan efek kedalaman. Sedangkan data lapangan diperoleh melalui metode transek kuadrat ukuran 1x1 meter persegi. Setiap transek diambil titik koordinatnya dan diamati jenis lamun serta persen tutupan lamun. Hasil analisis data lapangan menunjukkan bahwa Enhalus acoroides hanya ditemukan di Stasiun I. Sedangkan di Stasiun II dan Stasiun III ditemukan tiga jenis lamun dengan jumlah yang berbeda, yaitu Enhalus acoroides, Thalassia hemprichii, dan Halophila minor. Terdapat tiga kategori kepadatan lamun dari hasil klasifikasi citra, yaitu; lamun jarang, lamun sedang, dan lamun padat. Analisis Citra Landsat 8 OLI menunjukkan bahwa area kepadatan lamun di Perairan Desa Tanjung Tiram terdiri kategori lamun jarang seluas 8.58 Ha (13%), lamun sedang seluas 34.21 Ha  (17%), dan lamun padat seluas 6.48 Ha (69%) dengan total area sebesar 49.28 Ha. Sedangkan citra satelit Sentinel 2A sedikit berbeda dengan Landsat 8 OLI, Area tutupan lamun dengan kategori lamun jarang seluas 9.59 Ha (18%), selanjutnya lamun sedang sebesar 33.40 Ha (64%), dan lamun padat sebesar 9.54 Ha (18%) dengan total area 52.53 Ha. Tingkat akurasi klasifikasi pada citra satelit yang digunakan masing-masing sebesar 60.28% (Landsat 8 OLI) dan 73.04% (Sentinel 2A). Secara umum, tutupan lamun di lokasi penelitian dapat dinyatakan baik dan perlu dijaga kelestariannya.Kata kunci: Lamun, Citra LANDSAT 8 OLI, Sentinel 2A, Desa Tanjung Tiram.