Judul: Kelimpahan Fauna Tanah dan Hubungannya dengan Karakteristik Tapak pada Vegetasi Submontana di Taman Nasional Gunung Gede Pangrango
Abstrak: Fauna tanah merupakan komponen biotik tanah sebagai bioindikator kesuburan. Perbedaan ketinggian di Taman Nasional Gunung Gede Pangrango diduga mempengaruhi kelimpahan fauna tanah. Penelitian bertujuan mengidentifikasi perbedaan kelimpahan mesofauna dan makrofauna tanah di lokasi penelitian dan menganalisis hubungan faktor klimatis serta edafisnya. Analisis vegetasi dilakukan pada petak contoh 20 m x 20 m yang ditempatkan secara purposive sampling pada ketinggian 1.250, 1.350, 1.450 m dpl dan lahan terbuka (1.200 m dpl). Pengambilan sampel tanah dan pengukuran faktor lingkungan dilakukan pada subpetak contoh berukuran (1 m x 1 m). Hasil uji beda kelimpahan fauna tanah menunjukkan bahwa pada lokasi 1.250 dan 1.450 m dpl tidak berbeda nyata, 1.350 m dpl dan lahan terbuka menunjukkan perbedaan nyata. Kelimpahan fauna tertinggi terdapat pada lokasi 1.350 m dpl. Kelimpahan fauna terendah ditunjukkan pada lahan terbuka. Hubungan kelimpahan fauna tanah dengan faktor klimatis berupa suhu lingkungan dan intensitas cahaya memiliki nilai korelasi negatif, sedangkan kelembaban menunjukkan nilai positif. Faktor edafis seperti pH, Kapasitas Tukar Kation, memiliki nilai korelasi negatif dengan kelimpahan, sedangkan berat serasah, respirasi dan porositas tanah menunjukkan nilai korelasi positif.
Keyword: climatic, edaphic, population, soil fauna, submontane

Judul: Analysis of Soil Physical and Chemical Properties and Their Relationship with the Abundance of Soil Mesofauna and Macrofauna in Mount Gede Pangrango National Park
Abstrak: Kelimpahan fauna tanah dipengaruhi oleh berbagai faktor lingkungan meliputi faktor edafis, klimatis, dan keberadaan vegetasi di atasnya. Penelitian ini bertujuan menganalisis kelimpahan fauna tanah pada ketinggian tempat berbeda serta menganalisis pengaruh lingkungan terhadap kelimpahan fauna tanah. Penelitian dilaksanakan pada tiga ketinggian yang berbeda yaitu 1.550 m dpl, 1.650 m dpl, 1.750 m dpl, serta di lahan terbuka (1.200 m dpl). Hasil uji BNT menunjukkan kelimpahan fauna tanah yang berbeda nyata antara ketinggian 1.650 m dpl dengan lahan terbuka, sementara kelimpahan fauna tanah pada ketinggian 1.550 m dpl dan 1.750 m dpl tidak berbeda nyata pada selang kepercayaan 95%. Tutupan vegetasi turut memberikan kontribusi dalam kelimpahan fauna tanah dan dibuktikan dengan lahan terbuka yang memiliki kelimpahan fauna tanah terkecil. Hasil analisis korelasi menunjukkan bahwa intensitas cahaya dan suhu udara berkorelasi negatif, sedangkan kelembaban udara berkorelasi positif dengan kelimpahan fauna tanah. Faktor yang berkorelasi kuat dengan kelimpahan adalah berat basah serasah dan pH tanah., The abundance of soil fauna is influenced by various environmental factors including edaphic factors, climatic factors, and the presence of overlying vegetation. This study aims to analyze the abundance of soil fauna at different altitudes and analyze the influence of the environment on the abundance of soil fauna. The research was conducted at three different altitudes, namely 1.550 m asl, 1.650 m asl, 1.750 m asl, and in open land (1.200 m asl). The LSD test results showed that the abundance of soil fauna was significantly different between the altitude of 1,650 m asl and open land, while the abundance of soil fauna at an altitude of 1,550 m asl and 1,750 m asl was not significantly different at the 95% confidence interval. Vegetation cover also contributes to the abundance of soil fauna as evidenced by open land having the smallest abundance of soil fauna. The results of the correlation analysis show that light intensity and air temperature are negatively correlated, while air humidity is positively correlated with the abundance of soil fauna. Factors that are strongly correlated with abundance are litter wet weight and soil pH.
Keyword: altitude, climatic, diversity, edaphic, vegetation

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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