Judul: Hubungan Faktor Lingkungan dengan Keanekaragaman Jenis Kupu-Kupu di Tebet Eco Park, Jakarta Selatan
Abstrak: Populasi kupu-kupu berkaitan dengan faktor lingkungan pada suatu habitat, sehingga rentan terhadap perubahan kualitas lingkungan yang terdiri dari faktor abiotik dan biotik. Tebet Eco Park merupakan Ruang Terbuka Hijau yang sesuai untuk habitat kupu-kupu di tengah perkotaan. Penelitian bertujuan untuk mengkaji keanekaragaman dan komposisi jenis kupu-kupu pada dua area taman dan menganalisis pengaruh faktor lingkungan terhadap keanekaragaman jenis kupu-kupu di Tebet Eco Park. Metode pengumpulan data kupu-kupu menggunakan kombinasi metode transek dan titik hitung serta metode jebakan. Analisis Biplot dan korelasi Pearson digunakan untuk menentukan keeratan hubungan antara faktor lingkungan dengan keanekaragaman jenis kupu-kupu. Terdapat 761 individu dari 27 jenis kupu-kupu yang terdiri dari seluruh famili kupu-kupu tersebar di Taman Utara dan Taman Selatan. Indeks Keanekaragaman Jenis dan Indeks Kemerataan Jenis tertinggi diperoleh Taman Utara pada pagi hari (H’ = 2,524; E = 0,857), namun Indeks Kekayaan Jenis tertinggi diperoleh Taman Selatan pada pagi hari (Dmg = 3,903). Seluruh data keanekaragaman jenis kupu-kupu pada pagi hari lebih tinggi dibandingkan dengan siang hari. Intensitas cahaya matahari berkorelasi negatif sangat kuat terhadap keanekaragaman jenis kupu-kupu., Butterflies act as environmental bioindicators, so they are very susceptible to changes in environmental quality consisting of abiotic and biotic factors. Tebet Eco Park is a green open space that is suitable for butterfly habitats in the middle of urban areas. The research aimed to identify the diversity of butterfly species in two park areas and analyze environmental factors in the two areas that can influence the diversity of butterfly species in Tebet Eco Park. The butterfly data collection method uses a combination of transect and point counting methods and trap methods. Biplot analysis and Pearson correlation were used to determine the close relationship between environmental factors and butterfly species diversity. There were 761 individuals of 27 types of butterflies consisting of all butterfly families spread across North Park and South Park. The highest species diversity index and species evenness index values were found in North Park in the morning (H' = 2.524; E = 0.857), while the highest richness index was found in South Park in the morning (Dmg = 3.903). All data on butterfly species diversity in the morning is higher than in the afternoon. The intensity of sunlight has a very strong negative correlation with the diversity of butterflies.
Keyword: keanekaragaman, kupu-kupu, Taman Selatan, Taman Utara

Judul: Faktor-Faktor Lingkungan Penentu Keanekaragaman Kupu-Kupu di Hutan Kota Srengseng, Jakarta Barat
Abstrak: Faktor-faktor lingkungan penentu yang memengaruhi keanekaragaman kupu-kupu di Hutan Kota Srengseng dapat menjadi informasi dasar pengelolaan habitatnya. Penelitian bertujuan mengukur faktor lingkungan penentu (pakan larva, pakan kupu-kupu, tumbuhan shelter, suhu, kelembapan, Leaf Area Index, kecepatan angin, kebisingan, dan sumber air) serta menganalisis hubungannya dengan keanekaragaman kupu-kupu. Mengukur keanekaragaman, kekayaan, kemerataan, kesamaan, dominansi, menggambarkan sebaran spasial kupu-kupu berdasarkan perbedaan kondisi biofisik tapak. Hasil penelitian menemukan area depan dipengaruhi tumbuhan shelter, pakan kupu-kupu, pakan larva, kebisingan, kecepatan angin, suhu. Area belakang dipengaruhi sumber air, kelembapan, LAI. Area tengah tidak dipengaruhi faktor lingkungan apapun. Sebanyak 36 jenis kupukupu dari 5 famili ditemukan: Hesperiidae 3 jenis, Lycaenidae 8 jenis, Nymphalidae 14 jenis, Papilionidae 5 jenis, Pieridae 6 jenis. Keanekaragaman dan kekayaan jenis tertinggi diperoleh area depan (H’= 3,063; Dmg= 6,435), kemerataan jenis tertinggi diperoleh area tengah (E= 0,664), kesamaan jenis tertinggi diperoleh area tengah dan belakang (Sj= 0,62). Area depan merupakan lokasi paling mendukung keanekaragaman kupu-kupu karena didukung faktor tumbuhan pakan larva dan kupu-kupu, tumbuhan shelter, LAI, dan sumber air., Determinant environmental factors affecting butterfly diversity in Srengseng City Forest could be used as information for its habitat management. Research aimed to measure determinant factors (larval and butterfly foodplant, shelter plant, temperature, humidity, Leaf Area Index, wind speed, noise, water sources) as well as analyzing their relationship with butterfly diversity. Measure diversity, richness, evenness, similarity, dominance and spatial distribution of butterfly species based on site biophysical conditions differences. Results found front area affected by shelter plants, butterfly and larval foodplants, noise, wind speed, temperature. Back area affected by water source, humidity, LAI. Middle area was not affected by any environmental factors. As many as 36 species of butterflies from 5 families were found: Hesperiidae 3 species, Lycaenidae 8 species, Nymphalidae 14 species, Papilionidae 5 species, Pieridae 6 species. Highest diversity and richness in front area (H'= 3,063; Dmg= 6,435), highest evenness in middle area (E= 0,664), highest similarity in middle and rear area (Sj= 0,62). Front area supported butterfly diversity the most because it was supported by foodplants for larvae and butterflies, shelter plants, LAI, and water source.
Keyword: butterflies, diversity, Srengseng Urban Forest

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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