Judul: Diversity and Abundance of Canopy Spiders in Different Types of Land Use in the Taman Nasional Bukit Duabelas, Jambi Province
Abstrak: Penurunan tutupan kanopi pada kawasan hutan hujan tropis berdampak negatif terhadap keberlangsungan hidup spesies di dalamnya, tidak terkecuali Arthropoda. Salah satu kelompok Arthropoda yang berperan penting dalam keseimbangan ekosistem adalah kelompok Araneae (laba-laba). Penelitian ini bertujuan mempelajari keanekaragaman, kelimpahan, dan komposisi laba-laba kanopi pada empat tipe penggunaan lahan, mengetahui pengaruh transformasi habitat terhadap komposisi laba-laba, dan mengetahui spesies unik apa saja yang terdapat pada berbagai tipe penggunaan lahan. Pengambilan sampel dilakukan di lanskap Taman Nasional Bukit Duabelas (TNBD) pada empat tipe penggunaan lahan diantaranya : hutan, hutan karet, perkebunan karet, perkebunan kelapa sawit. Setiap tipe penggunaan lahan dipilih 4 plot inti dan masing-masing plot inti terdiri atas 3 subplot. Serangga yang berjatuhan saat proses pengasapan akan tertampung di dalam 8 wadah (1 m x 1 m) yang telah dipasang di bawah kanopi. Sampel yang berhasil dikumpulkan disortir dan diidentifikasi Di Laboratorium Pengendalian Hayati, Departemen Proteksi Tanaman, Institut Pertanian Bogor. Sampel yang dapat dikumpulkan sebanyak 1879 laba-laba, yang terdiri dari 24 famili dan 405 morfospesies. Terdapat famili yang memiliki morfospesies paling melimpah yaitu Theridiidae (89) dengan persentase sebesar 21,97% dari jumlah morfospesies yang diidentifikasi. Hasil penelitian menunjukkan tipe penggunaan lahan memengaruhi keanekaragaman dan komposisi laba-laba, akan tetapi tidak memengaruhi kelimpahan laba-laba. Keanekaragaman dan kelimpahan laba-laba lebih tinggi di hutan dan hutan karet dibandingkan perkebunan karet dan kelapa sawit. Hal ini berarti bahwa transformasi habitat berperan penting dalam keanekaragaman dan kelimpahan laba-laba kanopi pada berbagai tipe penggunaan lahan., Decrease canopy cover in tropical rain forest areas has a negative impact on the survival of the species in environment, including arthropods. One of the arthropod groups that play an important role in the ecosystem is the Araneae group (spiders). This study aims to study the diversity, abundance and composition of canopy spiders in different types of land use, to determine the effect of habitat transformation on the composition of spiders and find out what unique species are found in various types of land use. Sampling was carried out in the Bukit Duabelas National Park (TNBD) landscape on four types of land use including: forest, rubber forest, rubber plantation, oil palm plantation. For each land use type, 4 core plots were selected and each core plot consisted of 3 subplots. All arthropods that fell during the smoking process were captured by 8 containers of 1 m x 1m in size installed under the plant canopy. Samples that have been collected, sorted and identified in the Biological Control Laboratory, Department of Plant Protection, Bogor Agricultural University. Overall there were 1879 spiders collected, consisting of 24 families and 405 morphospecies. The most abundant morphospecies is Theridiidae (89) which contained 21,97% of all identified morphospecies. The results of this research showed land use type influencing the diversity and composition of spiders, but it does not influence the abundance of spiders. The diversity and abundance of spiders is higher in forest and rubber forests than rubber and oil palm plantations. This means that habitat transformation plays an important role in the diversity and abundance of canopy spiders in various land use types
Keyword: composition, deforestation, forest

Judul: Diversity of Dominant Diptera in Tree Canopies in Lowland Rainforest Landscapes, Jambi Province
Abstrak: Hutan hujan tropis dataran rendah di wilayah Jambi mengalami penurunan tutupan kanopi secara masif akibat alih fungsi lahan menjadi perkebunan monokultur. Konversi lahan menyebabkan penurunan kelimpahan dan kekayaan spesies serangga seperti semut, Hymenoptera parasitoid, dan kumbang. Sampai saat ini, belum ada laporan penelitian mengenai dampak konversi lahan terhadap kelimpahan dan kekayaan spesies Diptera di Sumatra, khususnya di Bukit Duabelas dan Hutan Harapan, Jambi. Penelitian ini bertujuan mengetahui dampak konversi hutan menjadi perkebunan karet dan sawit, pengaruh musim, habitat riparian, dan lanskap terhadap kelimpahan dan kekayaan spesies Diptera kanopi, khususnya di Jambi. Pengambilan sampel dilakukan dengan teknik pengasapan di empat tipe penggunaan lahan (hutan alami, hutan karet, perkebunan karet, dan perkebunan sawit), dua musim (kemarau dan hujan), dua habitat (riparian dan nonriparian), dan dua lanskap (Bukit Duabelas dan Hutan Harapan). Jumlah Diptera kanopi yang diperoleh yaitu 42 333 individu dari 29 subfamili, 109 genus, dan 947 spesies yang diketahui. Penelitian ini menunjukkan bahwa konversi hutan menjadi perkebunan menurunkan kelimpahan dan kekayaan spesies Diptera kanopi. Kelimpahan Diptera kanopi terendah ditemukan pada perkebunan sawit, sedangkan kekayaan spesies terendah ditemukan pada perkebunan karet. Komposisi Diptera kanopi paling mirip yaitu pada hutan alami dan hutan karet, sedangkan komposisi Diptera kanopi paling berbeda ditemukan pada hutan alami dan perkebunan sawit. Musim hujan meningkatkan kelimpahan dan kekayaan spesies Diptera kanopi. Keberadaan habitat riparian meningkatkan kelimpahan Diptera kanopi, tetapi tidak memengaruhi kekayaan spesiesnya. Lanskap Bukit Duabelas memiliki kelimpahan dan kekayaan spesies Diptera kanopi yang lebih tinggi daripada Hutan Harapan., The lowland tropical rainforests in Jambi have experienced a massive decline in canopy cover, a direct consequence of land conversion into monoculture plantations. This drastic change in land conversion reduced the abundance and species richness of canopy insects, including ants, butterflies, parasitoid wasps, and beetles. It is crucial to note that, to date, research has yet to be conducted on the abundance and species richness of Diptera in Sumatra, particularly in Bukit Duabelas and Harapan Rainforest, Jambi, in the context of land conversion. This research aims to determine the impact of forest conversion into rubber and oil palm plantations, the effect of seasons, riparian habitats, and landscapes on the abundance and species richness of canopy Diptera, especially in Jambi. Canopy Diptera samples were collected using fogging in four land-use systems (forest, jungle rubber, rubber plantation, and oil palm plantation), two seasons (dry and rainy), two habitats (riparian and nonriparian), and two landscapes (Bukit Duabelas and Harapan Rainforest). A total of 42 333 individuals were collected and identified to morphospecies level, belonging to 10 families, 29 subfamilies, 109 genera, and 947 known species. The finding of this study indicates that the conversion of forests into plantations reduces the abundance and species richness of canopy Diptera. The lowest abundance of canopy Diptera was found in oil palm plantations, while the lowest species richness was in rubber plantations. Canopy Diptera in forests has a similar composition to those in jungle rubbers, while it was most different in oil palm plantations. The rainy season increases the abundance and the species richness of canopy Diptera. The riparian habitat increased the abundance of canopy Diptera but did
Keyword: arboreal insects, biodiversity, flies, food web, mosquitos

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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