• Korean Journal of Environment and Ecology
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• v.21 no.5
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• pp.449-455
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• 2007

To offer basic data for restoration technology development of the evergreen broad-leaved forest, this researcher did monitoring on the restoration project of the evergreen broad-leaved forest implemented in Dadohaesang(Marine) National Park for three years starting the year 2005, As a result of the monitoring job of tree height and survival rate of the evergreen broad-leaved forest on the 5 model afforestation-testing sites subsequent to the slanting surface, size of island, and whether the pastured livestock exist or not, it was found that the tree height & survival rate of the evergreen broad-leaved trees planted on the ridge parts of the southwest slanting surface were in better condition than those of the evergreen broad-leaved trees planted on the ridge parts of the northeast slanting surface. The survival rate of the evergreen broad-leaved tree planted on a big island was revealed to be higher than that of the evergreen broad-leaved tree planted on a small island. In addition, the survival rate of the evergreen broad-leaved tree planted in a place where livestock was pastured was revealed to be much lower than that of the evergreen broad-leaved tree planted in a place where there was no livestock. Conclusively, there showed a good tree hight and survival rate of the evergreen broad-leaved tree planted on the ridge parts of the southwest slanting surface, on a big island, and at the place where there was no pastured livestock.

• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.648-657
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• 2008

This research was conducted to investigate the breeding density and seasonal food items of the magpies in Jeju Island and the near-manned islets. The examination of nest distribution to determine breeding density was performed during breeding season from February 2006 to April 2008, and that of food items from May 2006 to February 2008. A total of 2,113 nests were found across Jeju Island, the average density was $1.33\;nest/km^2$, and the magpies were distributed up to 600 meters above the sea level. The nest density was the highest in the central areas of Jeju Island, with 688 nests at $3.61\;nest/km^2$, while that in the eastern areas was the lowest, with 214 nests at $0.66\;nest/km^2$. In terms of the number of nests depending on the height above the sea level, 1,172 nests, which was equivalent to the density of $1.85\;nest/km^2$, was observed below 100m and highest among the intervals of height, but 16 nests found at 500-600m were the lowest, corresponding to $0.20\;nest/km^2$. The number of nests found in the manned islets near Jeju Island was eight in Biyang-do with the density of $15.38\;nest/km^2$, nine in U-do with $1.49\;nest/km^2$, and one in Gapa-do with $1.15\;nest/km^2$, whereas none of nests were observed in Mara-do. The contents of stomach consisted of 17 types of prey sources including countless bones, eggshells, plants, and seed, most of which were the individuals of the order Coleoptera. In spring and summer, the foraging frequency for invertebrate animals such as insects was high, but less than 30% in winter. In contrast, the magpies preyed upon plants and seeds at the frequency of 10% and 30%, respectively, in spring, while the foraging frequencies for both of them were 100% in winter and higher than any of other seasons. Eggshells and bones of birds were also detected infrequently. If the density of the magpies, which may play role as the upper predator within the ecosystem, increases, it would be expected to affect directly the reduction of the number of the species and population of endemic animals such as small birds and reptiles, etc. Therefore, it is considered that long-term monitoring for the density of the magpies and precaution is prerequisite to minimize adverse effects on ecosystem.