Judul: Habitat Suitability Modelling of Proboscis Monkey (Nasalis larvatus Wurmb, 1781) in Sekonyer River Tanjung Puting National Park, Central Kalimantan
Abstrak: Bekantan (Nasalis larvatus) merupakan spesies endemik pulau Kalimantan yang meliputi wilayah Indonesia, Malaysia, dan Brunei. Sebaran spesies ini terbatas pada habitat tertentu yang meliputi hutan bakau, hutan rawa, dan hutan riparian. Laju deforestasi habitat bekantan cukup tinggi sehingga berdampak pada penurunan populasi bekantan. Penelitian dilakukan pada bulan Februari-April 2020, dengan melakukan pengamatan di sepanjang aliran Sungai Sekonyer untuk mengetahui sebaran dan kondisi habitat. Analisis MaxEnt dilakukan untuk mendapatkan model serta nilai kontribusi variabel kesesuaian habitat. Hasil penelitian menunjukkan terdapat 47 jenis tumbuhan dari 27 famili yang 4 diantaranya merupakan pakan paling disukai bekantan. Kondisi habitat di Kawasan hutan sekitar Sungai Sekonyer dapat dikatakan baik, dilihat dari nilai kerapatan yang tinggi dari setiap tingkat pertumbuhannya. Habitat bekantan di Sungai Sekonyer sudah sesuai, dilihat dari masih tersedianya sumber kebutuhan hidup bekantan seperti sumber air, pakan, dan tempat berlindung. Model kesesuaian habitat bekantan dapat diterima dengan nilai AUC sebesar 0,966. Variabel kesesuaian habitat bekantan yang memiliki kontribusi paling besar adalah sungai dan tutupan lahan hutan rawa., he proboscis monkey (Nasalis larvatus) is an endemic species to Borneo's island and is largely confined to mangrove, riverine, and swamp forests. The rate of deforestation and habitat loss of the proboscis monkey is a significant threat to decreasing their population. This research was conducted during February-April 2020 by making observations along the Sekonyer River of Tanjung Puting National Park to determine the distribution and condition of the habitat. Using the maxent analysis, the model and the value of the contribution of the habitat suitability variable were obtained. There were 47 species of vegetation (27 families), four species were the most preferred food of proboscis monkeys. Habitat conditions in the forest area around the Sekonyer River were still quite good, seen from each growth rate's high-density value. The proboscis monkey habitat in the Sekonyer River was suitable, as seen from the availability of sources of life necessities such as water, food, and shelter. The proboscis monkey's habitat suitability model was acceptable with an AUC value of 0.966. The proboscis monkey's habitat suitability variables that had the most significant contribution were rivers and swamp forest land cover.
Keyword: Habitat suitability, proboscis monkey, Tanjung Puting National Park

Judul: Patch Habitat Characteristics and Metapopulation of Proboscis Monkey (Nasalis larvatus) in The Buffer Zone of Sebangau National Park
Abstrak: Bekantan merupakan primata endemik Kalimantan yang dilindungi pemerintah. Populasi bekantan terpecah menjadi sub-sub populasi akibat fragmentasi hutan hingga membentuk metapopulasi sehingga rentan terhadap kepunahan lokal. Daerah penyangga Taman Nasional Sebangau merupakan habitat bekantan yang terfragmentasi, berpotensi banyak gangguan. Tujuan penelitian ini adalah: 1) mengetahui kondisi dan karakteristik patch habitat bekantan; 2) mengetahui sebaran, jumlah populasi, variasi kelompok dan kelas umur bekantan; dan 3) mengetahui tipe metapopulasi, prospek kelestarian dan memperkirakan kepunahan lokal bekantan di daerah penyangga Taman Nasional Sebangau. Habitat bekantan daerah penyangga Taman Nasional Sebangau didominasi tipe patch berupa hutan riparian (42,37%), badan air dan danau (17,93%), rawa (16,71%), dan open area (14,36%). Bentuk geometri patch habitat tidak beraturan karena dipengaruhi oleh pemanfaatan lahan dan kejadian kebakaran hutan. Tumbuhan penyusun habitat bekantan sedikitnya 106 jenis pohon dalam 70 genus, dan 38 famili. Jenis vegetasi dengan kepentingan tinggi (INP) antara lain Cephalomappa beccariana, Elaeocarpus stipularis, Litsea accedens, Gluta velutina, Syzygium sp. 1, dan Shorea balangeran. Teridentifikasi 56 jenis pohon pakan bekantan, yaitu Cephalomappa beccariana, Artocarpus teysmannii, Gluta velutina, Syzygium sp., Lophopetalum javanicum, dan Sonneratia caseolaris. Pola sebaran bekantan menunjukkan pola mengelompok (Morisita index; Ip:0,54). Jumlah populasi bekantan daerah penyangga Taman Nasional Sebangau berkisar antara 1389-1736 individu dengan kepadatan populasi 8,01 individu/km², kepadatan kelompok 0,65 kelompok/km², serta nisbah kelamin 1:5,6. Jumlah kelompok yang dijumpai adalah 114 kelompok meliputi 109 one male units, tiga kelompok all mall units, dan dua soliter (jantan dewasa dan remaja). Berdasarakan kelas umur ditemukan jantan dewasa 8,62%, betina dewasa 48,19%, remaja 19,42%, anak 18,55%, dan bayi 5,22%. Terdapat delapan metapopulasi yang terbagi menjadi tiga tipe, yaitu patchy metapopulation (50%), classic metapopulation (37,5%), dan non-equilibrium metapopulation (12,5%). Berdasarkan semua skenario, empat metapopulasi patchy, yaitu Keruing, Muara Bulan, Tewang Perigi Timur, dan Mendawai Barat dapat bertahan lebih dari 80 tahun. Sebaliknya, metapopulasi classic (Asam Kumbang, Tewang Perigi Barat, dan Mendawai Timur) dan metapopulasi non-equilibrium (Landabung) memiliki risiko kepunahan yang beragam. Secara keseluruhan metapopulasi bekantan di Daerah Penyangga Taman Nasional Sebangau diperkirakan akan mengalami penurunan populasi sebesar 30,79% selama 80 tahun. Skenario pencegahan kebakaran hutan dan penegakan hukum memperlambat penurunan populasi 14,57%, sedangkan skenario pemulihan ekosistem diperkirakan akan meningkatkan populasi bekantan 23,41%., The proboscis monkey (Nasalis larvatus) is a Borneo endemic species that is protected by the government. The population is divided into subpopulations due to forest fragmentations to form metapopulations, and highly vulnerable to local extinctions. The Sebangau National Park’s buffer zone is a proboscis monkey habitat that is fragmented and has the potential for many disturbances. The objectives of this study were: 1) to identify the conditions and the characteristics of the proboscis monkey patch habitat; 2) to analyze the distribution, population size, group variation, and sex ratio of proboscis monkeys; c) to figure out the type of metapopulation, population survival, and the threat that causes the local extinction of proboscis monkey in the buffer zone of Sebangau National Park. The proboscis monkey habitat in the buffer zone of Sebangau National Park is dominated by patch types such as riparian forests (42,37%), water bodies and lakes (17,93%), swamps (16,71%), and open areas (14,36%). The patch geometry is irregular and influenced
Keyword: proboscis monkey, patch habitat, metapopulation, grouped

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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