• Title/Summary/Keyword: Prey selection

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A study on select of common Kestrel(Falco tinnunculus) hunting areas in breeding session (번식기 황조롱이(Falco tinnunculus)의 사냥 장소 선택에 관한 연구)

  • Won, Il Jae;Park, Min Cheol;Park, Hyun Doo;Cho, Sam Rae
    • Journal of Wetlands Research
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    • v.18 no.4
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    • pp.350-356
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    • 2016
  • The biggest factor in the success of breeding animals is selection of foods, which is determined by quality and quantity of habitats(Newton, 2003), in the case of This high biomass wetlands as an indicator of ecosystem function about Common Kestrel's choice of hunting area is expected to be an important clue of quality and quantity of habitats. For this study, it is divided into four types(Glasslands, Paddy fields, Dry fields, Rparian land) about Common Kestrel's hunting area in Yugu-eup, Gongju-si, Chungcheongnam-do, Recorded the behavior of Common Kestrel for three years during the breeding season from March to June(2014~2016). Result of investigation, hunting area showed a high hunting behavior in riversides and flight-hunting was frequently investigated from may to June. In addition flight-hunting's main food acquisition is mammal(the vole), while perching behavior's main food acquisition is insect according to the fact flight-hunting were mainly done in riversides, perching behavior were highly investigated than flight-hunting at glasslands and paddy fields and dry field. Hunting spot's coverage rate of plants covering the ground showed differences depending on hunting areas, but height of plants were not significant. Height of the plant according to hunting methods of flight-hunting to catch mammal(vole) was analyzed to prefer lower height than perching behavior Based on these results riversides are considered as a very important environmental factors for Common Kestrel's prey selection in breeding session.

Mass culture of the brackish water cyclopoid copepod Paracyclopina nana Smirnov (기수산 요각류 Paracyclopina nana의 대량배양)

  • Lee, Kyun-Woo;Choi, Young-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.262-266
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    • 2016
  • Marine copepods are ideal live prey for fish larvae, and many studies on the mass culture of the organism have been reported. This study performed a mass culture of the brackish copepod Paracyclopina nana containing nauplius and C4-adult production methods. In nauplius production, the harvested nauplii over 95% were comprised of N1 and N2. Daily mean nauplius production of two trials for 15 days were $6.9{\times}10^6$ and $7.2{\times}10^6$ individuals, respectively. The densities of the adult females were maintained at a similar level of the initiation during production. In C4-adult production, the proportion of harvested copepods containing C4-adult males, females and ovigerus females were 49%, 28%, and 18%, respectively. The daily mean nauplius production of the two trials for 16 days were $8.2{\times}10^5$ and $9.0{\times}10^5$ individuals, respectively. As a result, the continuous production of P. nana using the mass production system was successful. Therefore, the continuous and stable feeding for fish larvae in aquaculture would be possible by the selection of the copepod culture method depending on the mouth size of the fish.

Habitat Distribution Change Prediction of Asiatic Black Bears (Ursus thibetanus) Using Maxent Modeling Approach (Maxent 모델을 이용한 반달가슴곰의 서식지 분포변화 예측)

  • Kim, Tae-Geun;Yang, DooHa;Cho, YoungHo;Song, Kyo-Hong;Oh, Jang-Geun
    • Korean Journal of Ecology and Environment
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    • v.49 no.3
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    • pp.197-207
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    • 2016
  • This study aims at providing basic data to objectively evaluate the areas suitable for reintroduction of the species of Asiatic black bear (Ursus thibetanus) in order to effectively preserve the Asiatic black bears in the Korean protection areas including national parks, and for the species restoration success. To this end, this study predicted the potential habitats in East Asia, Southeast Asia and India, where there are the records of Asiatic black bears' appearances using the Maxent model and environmental variables related with climate, topography, road and land use. In addition, this study evaluated the effects of the relevant climate and environmental variables. This study also analyzed inhabitation range area suitable for Asiatic black and geographic change according to future climate change. As for the judgment accuracy of the Maxent model widely utilized for habitat distribution research of wildlife for preservation, AUC value was calculated as 0.893 (sd=0.121). This was useful in predicting Asiatic black bears' potential habitat and evaluate the habitat change characteristics according to future climate change. Compare to the distribution map of Asiatic black bears evaluated by IUCN, Habitat suitability by the Maxent model were regionally diverse in extant areas and low in the extinct areas from IUCN map. This can be the result reflecting the regional difference in the environmental conditions where Asiatic black bears inhabit. As for the environment affecting the potential habitat distribution of Asiatic black bears, inhabitation rate was the highest, according to land coverage type, compared to climate, topography and artificial factors like distance from road. Especially, the area of deciduous broadleaf forest was predicted to be preferred, in comparison with other land coverage types. Annual mean precipitation and the precipitation during the driest period were projected to affect more than temperature's annual range, and the inhabitation possibility was higher, as distance was farther from road. The reason is that Asiatic black bears are conjectured to prefer more stable area without human's intervention, as well as prey resource. The inhabitation range was predicted to be expanded gradually to the southern part of India, China's southeast coast and adjacent inland area, and Vietnam, Laos and Malaysia in the eastern coastal areas of Southeast Asia. The following areas are forecast to be the core areas, where Asiatic black bears can inhabit in the Asian region: Jeonnam, Jeonbuk and Gangwon areas in South Korea, Kyushu, Chugoku, Shikoku, Chubu, Kanto and Tohoku's border area in Japan, and Jiangxi, Zhejiang and Fujian border area in China. This study is expected to be used as basic data for the preservation and efficient management of Asiatic black bear's habitat, artificially introduced individual bear's release area selection, and the management of collision zones with humans.