Judul: Diversity of Reptiles Based on Habitat Disturbance in Production Forest Areas in Boven Digoel Regency South Papua Province
Abstrak: Aktivitas manusia dapat menyebabkan penurunan kualitas habitat termasuk reptil. Penelitian ini bertujuan mendeskripsikan kondisi umum habitat, mengidentifikasi keanekaragaman, kekayaan, kemerataan, dan kesamaan komunitas reptil berdasarkan tipe gangguan habitat di kawasan hutan produksi Kabupaten Boven Digoel, Papua Selatan. Metode penelitian yang digunakan adalah Visual Encounter Survei (VES) dan jebakan lem (Glue Trap). Ditemukan 176 individu dari 5 famili dengan 18 jenis yang berbeda, namun kekayaan jenis tersebut masih berpotensi meningkat berdasarkan kurva akumulasi jenis dan indeks Schao. Keanekaragaman dan kekayaan jenis tertinggi berada di habitat kurang terganggu (H’= 1,113 dan Dmg= 2,495). Kemerataaan jenis di ketiga tipe gangguan habitat tergolong rendah (E= 0,249-0,485) karena terdapat spesies yang mendominasi yaitu Carlia aenigma. Komunitas reptil habitat belum terganggu bersifat unik karena berbeda dengan habitat yang lainnya., Human activities can cause a decrease in the quality of habitat, including reptiles. This research aims to describe the general condition of the habitat, identify the diversity, richness, evenness, and similarity of reptile communities based on the habitat disturbance in the Production Forest Area Boven Digoel Regency, South Papua. Visual Encounter Survey (VES) and glue trap (Glue Trap) are used as research methods. Obtained 176 individuals from 5 families with 18 different species. The richness of these species still has the potential to increase based on the species accumulation curve and the Schao index. The highest species diversity and richness were in less disturbed habitats (H'= 1,113 and Dmg= 2,495). The evenness of species in the three types of habitat disturbance is relatively low (E= 0,25-0,48) because there is a dominating species, Carlia aenigma. The undisturbed habitat of the reptile community is unique because it is different from other habitats.
Keyword: habitat, keanekaragaman, reptil

Judul: Keanekaragaman Reptil pada Berbagai Tipe Habitat Terestrial di Hutan Harapan, Sumatera
Abstrak: Hutan Harapan, yang terletak di Jambi dan Sumatera Selatan, merupakan hutan restorasi dari hutan produksi yang rusak. Meskipun terdapat laporan tentang keanekaragaman kadal, tetapi hanya terbatas di Jambi dan tidak termasuk reptil lainnya. Tujuan dari penelitian ini adalah untuk mengidentifikasi komposisi reptil, membandingkan tingkat keanekaragaman dan kesamaan komunitas reptil antara lima habitat terestrial (areal terbuka, belukar muda, belukar tua, perkebunan karet dan hutan lahan kering sekunder) serta mengidentifikasi faktor-faktor dominan penentu kehadiran jenis reptil pada suatu tipe habitat di Hutan Harapan. Sebanyak 22 spesies reptil yang termasuk kedalam 9 famili, dua di antaranya adalah endemik (Cyrtodactylus quadrivirgatus, dan Trimeresurus hageni). Belukar tua memiliki keanekaragaman tertinggi (H’=2.068) dan areal terbuka memiliki nilai kemerataan tertinggi (E=0.992). Penggunaan habitat reptil dikelompokkan kedalam dua klaster, yakni: (1) tipe habitat belukar muda, kebun karet, belukar tua, hutan kering sekunder, dan (2) areal terbuka. Faktor lingkungan yang dominan mempengaruhi kehadiran jenis-jenis reptil adalah jumlah jenis pohon (p=0.005), jarak areal ke jalan (p=0.021), dan kerapatan vegetasi tingkat pertumbuhan pohon (p=0.139).
Keyword: Hutan Harapan, keanekaragaman, reptil

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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