Judul: The Utilization of Batai Tree (Paraserianthes falcataria) by Bird Communities at IPB Darmaga Campus
Abstrak: Pohon sengon (Paraserianthes falcataria) merupakan salah satu spesies pohon cepat tumbuh yang banyak ditanam masyarakat. Beberapa penelitian di Kampus IPB Darmaga menyebutkan adanya pemanfaatan pohon tersebut oleh komunitas burung, namun belum ada penelitian yang mengkaji peran pohon sengon dalam mendukung keanekaragaman burung. Penelitian ini bertujuan mengidentifikasi spesies burung yang memanfaatkan pohon sengon beserta penggunaan ruang dan waktu (pagi dan sore), serta perilaku burung dalam memanfaatkan pohon tersebut. Penelitian dilaksanakan antara bulan Januari – Mei 2023. Pengamatan perilaku burung dilakukan pada semua individu (scan sampling) dan dicatat pada akhir interval (5 menit) setelah waktu pengamatan dimulai (instantaneous sampling). Terdapat 33 spesies dari 21 famili yang memanfaatkan pohon sengon di Kampus IPB Darmaga dengan total perjumpaan sebanyak 1118 kali. Bagian atas tajuk merupakan ruang yang paling sering digunakan burung. Perjumpaan spesies dan individu burung yang memanfaatkan pohon sengon lebih banyak pada pagi hari. Burung sebagian besar memanfaatkan pohon sengon untuk diam baik mengamati sekitar ataupun beristirahat., The batai tree (Paraserianthes falcataria) is one of the fast-growing tree species commonly planted by communities. Several studies conducted at IPB Darmaga Campus have mentioned the utilization of this tree by bird communities, but there has been no research investigating the role of batai tree in supporting bird diversity. This study aims to identify bird species that utilize batai tree, as well as their spatial and temporal patterns of use (morning and evening), and the behaviors exhibited by birds while utilizing these trees. The study was conducted between January and May 2023. Observation of bird behavior was carried out for all individuals (scan sampling) and recorded at the end point of the interval (5 minutes) after the observation time began (instantaneous sampling). There were 33 species from 21 families observed utilizing batai tree at IPB Darmaga Campus, with a total of 1118 encounters. The upper canopy is the space that most often used by birds. Species and individual bird encounters were higher in the morning. Birds mostly utilized batai tree for perching, either for observing the surrounding or resting.
Keyword: batai, bird community, IPB Darmaga Campus

Judul: Interaction of Bird-Communities with Epiphytic Plants at IPB Dramaga Campus
Abstrak: Epifit memiliki pengaruh langsung maupun tidak langsung terhadap ekosistem di sekitarnya. Kehadiran epifit dapat meningkatkan kompleksitas habitat secara vertikal serta memberikan dampak positif bagi hewan, termasuk burung. Penelitian ini bertujuan mengidentifikasi epifit, pohon inang, dan burung, serta menganalisis hubungan antara komposisi epifit dan pohon inang dengan keanekaragaman dan kelimpahan burung. Penelitian dilakukan di tujuh lokasi di Kampus IPB Dramaga dari Desember 2022 hingga Mei 2023. Data biotik seperti jumlah dan jenis epifit, pohon inang, dan burung, serta data abiotik seperti suhu dan kelembapan dikumpulkan di setiap lokasi. Data dianalisis menggunakan perangkat lunak PAST untuk mendapatkan indeks keanekaragaman dan R untuk melihat korelasi antara burung dengan epifit. Hasil analisis menunjukkan adanya korelasi positif yang signifikan antara jenis epifit dan pohon inang dengan jenis burung. Taman Inovasi-Taman Konservasi dan Taman Hutan Kampus-Biofarmaka merupakan lokasi dengan keanekaragaman dan kelimpahan pohon, epifit, dan burung tertinggi. Lokasi yang memiliki keanekaragaman dan kelimpahan epifit yang tinggi memiliki suhu yang cenderung lebih rendah. Pycnonotus aurigaster, Aegithina tiphia, Sitta frontalis, dan Dicaeum trochileum adalah jenis burung yang memanfaatkan epifit. Keempat jenis tersebut memanfaatkan epifit Asplenium sp. dengan mencari pakan berupa invertebrata di sekitarnya., Epiphytes have direct or indirect influence on surrounding ecosystems. The presence of epiphytes can increase habitat complexity vertically and have a positive impact on animals, including birds. The objectives of this study were to identify species of epiphytes, host trees, and birds and to analyze the relationship between the composition of epiphytes, host trees, and bird diversity and abundance. The research was conducted at seven locations on IPB Dramaga Campus from December 2022 to May 2023. Biotic data, such as the number and type of epiphytes, host trees, and birds, and abiotic data, such as temperature and humidity were collected at each location. Data were analyzed using PAST to examine the diversity indices and used R to look correlation between birds and epiphytes. The analysis showed a significant positive correlation between the species of epiphytes and host trees with bird species. Taman Inovasi-Taman Konservasi and Taman Hutan Kampus-Biofarmaka have the highest diversity and abundance of trees, epiphytes, and birds. Locations with high diversity and abundance of epiphytes tend to have lower temperatures. Pycnonotus aurigaster, Aegithina tiphia, Sitta frontalis, and Dicaeum trochileum are bird species that utilize epiphytes. These four species use Asplenium sp. epiphytes by looking for invertebrates as food around them.
Keyword: Asplenium sp., insektivora, interaksi burung-epifit, Asplenium sp., bird-epiphyte interaction, insectivore

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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