Judul: Mangrove Rehabilitation Effectiveness and Carbon Stock Estimation in Harapan and Kelapa Island, Thousand Islands National Park, DKI Jakarta
Abstrak: Rehabilitasi ekosistem karbon biru, seperti mangrove, semakin banyak dilakukan di kawasan pulau-pulau kecil sebagai upaya pengelolaan untuk mengurangi dampak krisis iklim. Rehabilitasi mangrove pertama kali diinisiasi oleh pemerintah Indonesia pada tahun 1998 dengan melakukan penanaman mangrove. Kegiatan ini terus dilakukan hingga tahun 2008 dengan adanya kegiatan GERHAN yang dipimpin oleh KLHK. Namun, hasil dari pertumbuhan mangrove rehabilitasi tidak optimum. Hal ini disebabkan karena penanaman mangrove dilakukan pada kawasan rerataan terumbu datar yang bukan merupakan habitat alami dari mangrove sehingga tanaman mangrove cenderung kerdil. Hal ini akan mempengaruhi jumlah simpanan karbon pada mangrove rehabilitasi. Di sisi lain, masyarakat tidak memahami pemanfaatan langsung dari mangrove sehingga pengelolaan mangrove tidak berjalan dengan maksimal. Oleh karena itu, penelitian ini bertujuan untuk 1) mengevaluasi tingkat efektivitas mangrove rehabilitasi, 2) mengestimasi simpanan karbon dan nilai ekonomi pada mangrove rehabilitasi sebagai penyimpan karbon, 3) menyusun strategi pengelolaan mangrove rehabilitasi di Pulau Harapan dan Kelapa, Kepulauan Seribu. Evaluasi tingkat keberhasilan mangrove rehabilitasi dianalisis menggunakan parameter struktur komunitas mangrove, meliputi sintasan, pertumbuhan, tutupan relatif berdasarkan Perdierjen nomor P1/V-SET/2013. Indikator sosial juga menjadi perhatian dalam penelitian ini dengan mengukur partisipasi dan persepsi masyarakat menggunakan Skala Guttman dan Skala Likert. Perhitungan simpanan karbon menggunakan metode non-destruktif pada tegakan dan bawah permukaan mangrove, sedangkan perhitungan karbon tanah menggunakan metode metode Walkley & Black untuk menghitung kandungan C organik. Perumusan strategi pengelolaan mangrove rehabilitasi menggunakan analisis AHP. Hasil kajian mendapatkan bahwa efektivitas mangrove rehabilitasi di Pulau Harapan dan Kelapa tidak efektif dengan mengacu pada Perdirjen No. P.1/V SET/2013. Hal ini ditunjukkan dari parameter bahwa presentase tumbuh mangrove 16,52% yang terkategori rehabilitasi tidak berhasil dengan intensitas pemeliharaan berat. Cadangan total karbon mangrove rehabilitasi, khususnya pada spesiesRhizophora stylosa yaitu 634,54 ton C/ha dan nilai karbon sekuestrasi sebesar 2328,75 tCO2/ha, sedangkan nilai ekonomi karbon pada mangrove rehabilitasi mencapai Rp 375.202.308 untuk pasar bebas dan Rp 980.528.697 pada pasar wajib. Strategi dalam meningkatkan efektivitas pengelolaan mangrove adalah berfokus pada aspek ekonomi yaitu sosialisasi pemanfaatan mangrove bekerjasama dengan yayasan atau instansi lain, pengembangan usaha produk bakau melalui lembaga mangrove (SPKP), dan menciptakan pemasaran produk olahan mangrove dengan kriteria yang menjadi prioritas utama adalah aspek ekologi.
Keyword: mangrove rehabilitasi, karbon, pengelolaan mangrove, efektivitas, mangrove rehabilitation, carbon stock, effectiveness, management

Judul: Effectiveness of mangrove rehabilitation on pramuka island, seribu archipelago.
Abstrak: Mangrove ecosystem damage is generally caused by human activities, although it is undeniable, nature also has a considerable role. The damage will cause a reduction or even disappearance of system functions and benefits of mangrove for the community and the surrounding environment. To restore the damaged mangrove, it is necessary to attempt rehabilitation through mangrove management on Pramuka Island, Seribu Archipelago. The purpose of this study was (1) to examine the factors that determine the success of the rehabilitation of mangrove ecosystems on Pramuka Island, Seribu Archipelago, (2) to assess the effectiveness of the rehabilitation of mangrove ecosystems and the factors supporting the success and failure on Pamuka Island, Seribu Archipelago, and (3) to arrange the recommendations to improve the effectiveness of the rehabilitation of mangrove ecosystems on Pramuka Island, Seribu Archipelago. Assessment of mangrove rehabilitation success rate on Pramuka Island was done by analyzing several indicators of using an effectiveness index with taking into account also the environmental parameters of water quality such as temperature, flow velocity, salinity, pH, DO, TSS, nitrate, potassium, BOD5. Indicators of effectiveness of mangrove include eco-biologi indicators of mangrove rehabilitation that includes survival, growth and percent cover; and social indicators that include public participation and public perception. Results of this study showed that the majority of mangroves on Pramuka Island are the saplings, while for trees and seedlings only a small fraction. All existing mangrove rehabilitation was the result of the different planting years, only two trees ware considered a pre-existing natural mangrove long ago. Based on the measurement results, mangrove rehabilitation on Pramuka Island had a relative cover between 0.03 to 2.82%; growth of 13.33 to 32.50 cm/yr; and survival rate of 3.02 to 67.36%. Environmental conditions in the area of rehabilitation of mangrove waters are shallow water reef around the island stretches to a distance of about 500 m from the shoreline and the water quality is suitable for mangroves. Values of water quality measurements include temperature from 31.7 to 35 °C; flow velocity 0.1-0.3 m/s; TSS 4-16 mg/l; pH 7.54 to 8.20; salinity 25-28 psu; DO from 7.6 to 9.4 mg/l; nitrate from 0.039 to 0.156 mg/l; orthophosphate 0.002 to 0.283 mg/l; potassium 0.272 to 0.698; and BOD5 from 2.00 to 4.60 mg/l. Based on social conditions, all the people (100%) know about mangroves, both the function and existence. 60% of people also know that the mangrove on Pramuka Island is managed by TNKpS. In addition, people also take a role and participate in themanagement of the mangrove. Approximately 80% of respondents said had been involved in management efforts, including by contributing to maintain, not destroy the existence of mangroves and mangrove occasional cleaning of garbage. Community involvement is in line with the perceived benefits. 80% of vii respondents said that the mangroves are considered to lessen the blow of the waves, erosion and add coolness on the beach. Community involvement in management efforts can be improved if people know and can take advantage of direct utilization of mangrove like to candied fruit, wood utilization, etc.. So far there is no direct use
Keyword: mangrove ecosystem, TNKpS, ehabilitation, effectiveness

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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