예당저수지의 수변 농경지의 어류와 양서류 분포 특성을 파악하고자 실시되었다. 이를 위해 비수변 농경지를 대조군 지역으로 설정하고 수변 농경지의 어류와 양서류의 개체수 및 생물량 비교, 어류와 양서류 분포에 영향을 주는 환경요소 분석, 시기별 개체수 변동 특성을 연구하였다. 전체 조사 대상지역에서 포획된 어류종수는 8과 13종이며, 양서류 종수는 5종이었다. 수변 농경지에서는 미꾸리과 어류, 붕어, 잉어 등의 13종의 어종이 포획되었고, 비수변 농경지에서는 미꾸리 과 어류, 붕어 등의 3종의 어종이 포획되었다. 양서류는 황소개구리, 참개구리, 청개구리, 한국산개구리, 옴개구리 총 5종의 유생이 포획되었는데, 비수변 농경지에서는 5종의 양서류 유생이 포획되었고, 수변 농경지에서는 2종의 양서류 유생이 포획되었다. 수변 농경지와 비수변 농경지의 어류와 양서류 분포 특성을 분석한 결과, 수변 농경지에는 잉어과 어류가 많이 포획되었으며, 비수변 농경지에는 미꾸리과 어류가 많이 포획되었다. 어류의 분포에 영향을 주는 환경요소 분석결과, 잉어과 어류는 겨울철에 담수되고, 예당저수지와의 거리가 가까운 농경지에서 주로 출현할 가능성 이 높으며, 미꾸리과 어류는 산간 저수지로부터 용수가 공급되고, 논과 배수로가 잘 연결되어 있는 농경지를 선호하는 것으로 나타났다. 양서류의 경우, 비수변 농경지에서 수변 농경지보다 양서류의 유생이 많이 포획되었다. 수변 농경지에 서는 황소개구리가 우점하였고, 비수변 농경지에서는 참개구리가 우점하였다. 황소개구리 유생의 분포에 영향을 주는 주요 환경요소는 겨울철에 담수되고 예당저수지에 가까운 농경지에서 출현할 가능성이 높았고, 참개구리의 경우는 산까지의 거리가 가깝고 예당저수지까지의 거리가 멀수록 출현할 가능성이 높았다.

This study was conducted to survey the habitat selection by the Eastern Bean Goose Anser fabalis in the Upo wetland, Changnyeong gun. South Korea from October 2004 to March 2005. The mean number of Eastern Bean Geese was 2,104 individuals during the study period. The minimum number of about 100 individuals was observed in October 2004, and the maximum number of about 3,000 individuals was observed in November 2004 and January 2005. Fourteen sites were classified with respect to water depth and dominant food plant types, and the number of geese using the 14 sites was recorded every week. The sites that were mainly used were S-2 in Sajipo and Z-1 in Jjokjibeol in October, S-2 and S-4 in November, sites U-2 in Upo and Z-1 in December, sites U-2 and S-4 in January and February, and sites U-2 and Z-1 in March. Three aquatic plants, Scirpus fluviatillis, Trapa japonica, and Zizania latifolia were the main food for geese in the Upo wetland. We determined the monthly habitat selection indexes (Jacob’s index) for the three habitat types, which were classified according to three aquatic plant species. The habitat selection index of the area where Zizania latifolia predominated from October to February had the highest score of 0.40~0.47 among the three habitat types. This indicated that Bean Geese strongly preferred the habitat where Zizania latifolia predominated from October to February. By contrast, the habitat where Scirpus fluviatillis predominated was selected mainly in March. Faecal samples were collected randomly at the six sites mainly used by the geese each month. Zizania latifolia predominated in faeces from October to November, but the proportion of Scirpus fluviatillis and Trapa japonica in faeces increased from December to February.

Foraging preference in prey size and type is influenced by a variety of factors including energy requirements, season-dependent food availability, and social context (e.g. competition and predation risk). The oriental stork (Ciconia boyciana) is known as a wetland forager that inhabits human-managed wetlands such as paddy fields while breeding. However, it became an internationally endangered species. Information on its foraging preference is anticipated to play an important role in maintaining storks in captivity with a variety of food types as well as managing the food availability in foraging habitats of reintroduction sites. Specifically, the present study investigated the patterns of foraging preference of the subject in captivity as a partial study of the prerelease training and habitat management programs prior to reintroduction. The observations of foraging behavior of breeding adult storks included foraging preference in prey size (i.e. small, less than 6 cm, vs. large, larger than 6 cm, mudfish) during the incubation and nestling periods (March to April of 2009~2010) and prey type (i.e. mudfish, Misgurnus spp., crickets, Gryllus spp., and earthworms, Lumbricus spp.) during the postnesting period (October of 2009~2010). Our results indicated that storks in captivity not only preferred large to small mudfish independent of breeding stage but also preferred mudfish to crickets and earthworms. To our knowledge, captive storks did not appear to be constrained by providing offspring with various mudfish size and were likely dependent on mudfish, suggesting that a mudfish population in paddy fields should be monitored and managed for the main food resource for breeding storks prior to reintroduction.