Judul: The Diversity of Soil Surface Insects in Three Types Land Use in Sintang District, West Kalimantan
Abstrak: Serangga tanah merupakan organisme yang memiliki peran penting dalam proses penguraian bahan organik tanah, indikator kesuburan tanah dan menjaga keseimbangan ekosistem. Penelitian ini bertujuan untuk mengetahui keane- karagaman dan kelimpahan serangga permukaan tanah pada tiga tipe lahan karet yaitu perkebunan karet, agroforestri karet, serta hutan sekunder dan mengetahui serangga yang menyerang batang karet di Kabupaten Sintang Kalimantan Barat. Metode penelitian yang digunakan adalah observasi lapang, pengambilan sampel dengan pitfall trap dan pengukuran kondisi lingkungan, identifikasi serta analisis data pada tiga tipe lahan karet. Hasil penelitian menunjukkan bahwa ditemukan sebanyak 649 individu yang terbagi menjadi 8 ordo 11 famili 14 jenis. Kelimpahan tertinggi terdapat pada tipe lahan agroforestri karet sedangkan keanekaragaman tertinggi terdapat pada hutan sekunder. Jenis serangga ditemukan menyerang batang pohon karet baik yang mati maupun hidup adalah Coptotermes curvignathus di lahan agroforestri karet dan Reticulitermes flavipes di lahan hutan sekunder dan perkebunan karet. Kata kunci: biodiversitas, kerusakan, pitfall trap, serangga tanah, tanaman karet, Soil insects are organisms that have an important role in the process of decomposing soil organic matter, indicators of soil fertility, and maintaining ecosystem balance. This study aims to determine the diversity and abundance of soil surface insects on three types of rubber land, namely rubber plantations, rubber agroforestry, and secondary forests and the alarm that attacks rubber stems in Sintang District, West Kalimantan. The research method used was field observation, sampling with pitfall traps and measurement of environmental conditions, identification, and data analysis on three types of rubber land. The results showed that 649 individuals were found which were divided into 8 orders of 11 families of 14 species. The highest abundance was found in rubber agroforestry land types, the highest biodiversity was in secondary forest. The types of insects found attacking the rubber tree trunks, both dead and alive, were Coptotermes curvignathus in rubber agroforestry and Reticulitermes flavipes in secondary forest and rubber plantations. Keywords: biodiversity, damage, ground insects, pitfall trap, rubber plant
Keyword: biodiversity, damage, ground insects, pitfall trap, rubber plant

Judul: Keanekaragaman Semut pada Berbagai Tipe Penggunaan Lahan di Jambi
Abstrak: Conversion of tropical forests, mainly to agricultural area is the most important driver of tropical biodiversity loss. As dominant species in lowland forests, ant species diversity is prone to decline sharply due to forest transformation. This research was conducted to investigate the diversity of ants and its role in different land use. Ecological research was conducted in four types of land-use i.e. forest, jungle rubber, oil palm plantation and rubber plantation, located within two landscapes i.e. Bukit Duabelas National Park and Harapan Forest in Jambi, Indonesia. Each type of land use, four plots were selected for ant sampling. Ants were collected using baiting methods, combination between tuna and sugar. Ant diversity in Harapan Forest higher than in TNBD. In total, 66 species of ants belonging to 4 subfamilies and 20 genera were recorded from both area of Bukit Duabelas and Harapan. Surprisingly, the highest number of ant species was found in oil palm plantation. In addition, the compositions of ants based on its role showed differ among land-use types. It indicates that land-use change drive ant species composition.
Keyword: land use, foresty, ant diversity

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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