Judul: Spatial Modeling for Habitat Suitability of Sago (Metroxylon spp.) in Seram Island, Maluku
Abstrak: Sagu (Metroxylon spp.) merupakan salah satu tumbuhan pangan tropika Indonesia. Indonesia mempunyai areal penanam sagu cukup luas sagu, bahkan diperkirakan sekitar 60% areal penanaman sagu dunia. Salah satu wilayah yang banyak ditemukan sagu adalah Pulau Seram, Maluku. Besarnya potensi sagu yang terdapat di Pulau Seram dapat dijadikan modal pengelolaan sagu bagi Indonesia. Namun informasi terkait sagu, terutama mengenai data spasial sagu masih kurang. Oleh karenanya dilakukan penelitian dengan tujuan mengidentifikasi habitat, menganalisis faktor-faktor fisik yang mempengaruhi kesesuaian habitat serta menentukan pemodelan spasial kesesuaian habitat sagu yang tepat. Penelitian didasarkan oleh penelitian sebelumnya yaitu oleh Botanri (2010) dengan menggunakan data berupa citra Lansat -5 TM terdiri dari path 107/row 062, path 107/row 063, path 108/row 062 dan path 109/row 062, yang direkam pada 6 Juli 2007, 17 Juli 2007, 15 Agustus 2007 dan 29 July 2007. Peta tematik lain yang digunakan antara lain: peta jenis tanah, peta sungai dan titik distribusi sagu (Metroxylon spp.) di Pulau Seram Maluku serta citra ASTER GDEM Pulau Seram, Maluku, pengambilan pada 17 November 2011. Data tersebut diolah dengan menggunakan software ArcGIS 9.3 dan ERDAS 9.1. Proses analisis spasial dari ASTER GDEM menghasilkan peta ketinggian dan kemiringan lereng. Sedangkan proses spectral enhancement pada citra Pulau Seram menghasilkan peta Normalize Difference Vegetation Index (NDVI) Pulau Seram. Sehingga didapatkan faktor penentu kesesuaian yang digunakan yaitu: peta ketinggian, kemiringan lereng, jenis tanah, jarak dari sungai dan NDVI. Kemudian dengan SPSS 19.0 dilakukan analisis komponen utama dan analisis regresi logistik untuk meyusun model kesesuaian habitat berdasarkan kelima factor tersebut. Hasil analisis menunjukkan bahwa Metroxylon spp. menyebar hampir merata di Pulau Seram Maluku. Metroxylon spp. dapat ditemukan pada daerah-daerah dengan karakteristik seperti: 1). Ketinggian tempat antara 0-250 meter diatas permukaan laut. 2). Kemiringan lereng yang datar yaitu 0 – 8%. 3). Pada jenis tanah Alluvial. 4). Jarak dari sungai < 300 m. 5). Dengan nilai NDVI kisaran -0,25 hingga 0,25. Model kesesuaian habitat Metroxylon spp. yang didapat berdasarkan kedua analisis menunjukkan validasi 65,62% dengan perkiraan luas areal sagu sebesar 489.716,31 Ha untuk model kesesuaian berdasarkan analisis komponen utama dan 82,81% dengan perkiraan luas areal sagu sebesar 617.500,31 Ha untuk model kesesuaian berdasarkan analisis regresi logistik. Maka dapat dikatakan bahwa model kesesuaian berdasarkan analisis regresi logistik yang tepat digunakan untuk pembuatan pemodelan spasial kesesuaian habitat Metroxylon spp. di Pulau Seram, Maluku.
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Judul: Spatial Distribution, Autecology, and Biodiversity of Sagoo (Metroxylon spp.) in Seram Island, Maluku
Abstrak: Sago palm (Metroxylon spp.) is a tropical plant. Its area distribution in Indonesia is the largest in the world, covering 50-60 % of world’s Sago area. It is multifunction plant, however, it is still under utilized. Ecologicaly, sago palm well adapted on fresh water or peat swamp, riverine zone, surrounding water or swamp forests. Unfortunately, there is no any valid information on its area distribution. Moreover, regarding species diversity of Sago is also unclear. Based on the above facts, it is an urgent need to know its ecological aspect, spatial distribution and species diversity. The research was conducted in March to November 2009 at the Seram Island, Maluku. Spatial distribution was developed by Supervised classification of Landsat TM coupled with ground survey to collect Ground Control Points (GCPs) for accuracy assessment. Further field survey was done to collect autecological data. Isozyme analysis was also conducted to identify species diversity. Output supervised classification of Landsat-5TM image in 2007, showed that potential area of sago palm at the Seram Island was 18.239,8 ha. Characteristic of the habitat was distributed in the lowland (elevation less than 250 m asl), flat area, around river, near from beach, and on alluvium soil (sediment). Population structure of sago palm in the nature community follows young growth pattern, in wich rate seedling mortality was about 76,82 %. Regarding the species, M. rumphii Mart. species is the most dominant vegetation which cover 43,3 % of habitat. As adaptation strategy in swampy condition, sago palm form roots which was vertically directed to reach water surface. In sago palm community there was negative interspecific association indicated by Jaccard index less than 0,2. Abiotic component significant effected growth and sago fluor production. The variable that most have significantly effect to growth and sago flour production were micro temperature, micro relative humidity, bulk density, soil acidity, and salinity. The potential clump population at the Seram Island was about 3,2 million clump or approximately of about 1,5 million trunk of trees. M. rumphii Mart. and M. sylvestre Mart. species were the most potential with production capacity of about 566,04 kg starch/trunk and 560,68 kg starch/trunk, respectively. Genetic analysis by isozyme proved that initially known five species of Sago in the Seram Island was actualy only two species, namely Metroxylon rumphii Mart. (concist of M. rumphii Mart., M. sylvestre Mart., M. longispinum Mart, and M. microcanthum Mart.), and Metroxylon sagu Rottb.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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