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: Utilization of Ficus benjamina and Ficus hispida by Birds at IPB Darmaga Campus
Abstrak: Tumbuhan Ficus dikenal sebagai keystone species bagi berbagai jenis satwa di ekosistem hutan tropis. Beberapa famili burung diketahui memiliki interaksi simbiosis mutualisme dengan tumbuhan Ficus. Berbagai penelitian mengenai komunitas burung telah dilakukan di Kampus IPB Darmaga sebagai kampus yang memiliki potensi kenekaragaman hayati tinggi namun belum ada penelitian yang mempelajari interaksi antara komunitas burung dan Ficus. Penelitian ini bertujuan untuk mengidentifikasi jenis, pemanfaatan ruang dan waktu, serta perilaku burung yang memanfaatkan Ficus benjamina dan Ficus hispida. Penelitian dilakukan pada bulan Maret-April 2021. Pengumpulan data dilakukan pada 3 pohon contoh F. benjamina dan 3 pohon contoh F. hispida dengan menggunakan metode instantaneous-scan sampling. Sebanyak 18 spesies burung teramati memanfaatkan kedua spesies Ficus. Secara umum, pemanfaatan F. benjamina oleh burung lebih tinggi daripada F. hispida. Pemanfaatan ruang dan waktu oleh burung bervariasi pada tiap spesies Ficus. Perilaku ingestif menjadi perilaku yang paling banyak tercatat dibandingkan perilaku diam, bersuara, berpindah, dan agonistik., Ficus plants are known as keystone species for various types of animals in tropical forest ecosystems. Several bird families are known to have mutualistic symbiotic interactions with Ficus plants. Various studies on bird communities have been carried out at the Darmaga Campus of IPB as a campus that has high biodiversity potential, but there has been no research that studies the interaction between bird communities and Ficus. This study aims to identify the species, use of space and time, and behavior of birds that utilize Ficus benjamina and Ficus hispida. The study was conducted in March-April 2021. Data were collected on 3 focal trees of F. benjamina and 3 focal trees of F. hispida using the instantaneous-scan sampling method. A total of 18 bird species were observed utilizing both Ficus species. In general, the utilization of F. benjamina by birds was higher than that of F. hispida. The use of space and time by birds varies in each Ficus species. Ingestive behavior is the most recorded behavior compared to vigilance, vocal, locomotion, and agonistic behavior.
Keyword: Ficus, Kampus IPB Darmaga, komunitas burung, perkotaan

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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