Su-Kyung Kim

Estimating Detection Probabilities and Site Occupancy Rates of Three Anuran Species Using Call Surveys in Haenam Gun, Korea

We investigated the distribution of three anuran species, Three-striped pond frogs (Rana nigromaculata), Bullfrogs (Rana catesbeiana), and Narrow-mouthed toads (Kaloula borealis), in an administrative district, Haenam Gun, Junnam Province, Korea using volunteer call surveys. Twenty-eight volunteer call surveyors were assigned to each survey plot. Call surveys on whether the species are present or not were conducted for 5 minutes between 30 minutes after sunset and the midnight on rice fields and ponds from 10 April to 28 August in 2005. Depending on species, call surveys were carried out at seven to 28 plots with average 8.4 to 10.7 visits per the plot. We calculated the detection probabilities and occupancy rates of the three species using four models with three covariates: temperature, humidity, and the amount of water at the habitat. The model average detection probabilities of three anuran species of R. nigromaculata, R. catesbeiana, and K. borealis were 0.53, 0.74, and 0.41 respectively, and the site occupancy rates of them were 0.93, 0.94, and 0.86 respectively. Our results indicate that R. nigromaculata, R. catesbeiana, and K. borealis are common in Haenam Gun.

Effectiveness of mating call playbacks in anuran call monitoring: A case study of three‐striped pond frogs (Rana nigromaculata)

Abstract We studied the effectiveness of mating call playbacks on call monitoring of three‐striped pond frogs (Rana nigromaculata). Playback experiments were conducted between 2100 to 0030 at 15 sites located at Chungwon, Chungbuk, and Yeongi, Chungnam, in May 2005. We recorded call responses of 25 males to two different call playbacks, (i) single mating calls from a single male and (ii) chorus mating calls from five males, by randomly presenting the calls with a 15 min‐gap between the two playbacks. We compared the number of response calls of the focal males for three min before, during, and after the playbacks. Five of 25 males were silent before stimulus presentation, but all the males emitted calls after the playbacks. The number of calls in response to single playback calls significantly differed among the three playback periods, where males gave more calls during the playback than before or after the playbacks. In addition, subject males presented significantly more calls to single call playbacks than to chorus call playbacks. The results of this study suggest that playback using repeated single mating calls is effective in call monitoring of R. nigromaculata males.

Evaluation of Historic Breeding Habitats with a View to the Potential for Reintroduction of the Oriental White Stork (Ciconia boyciana) and Crested Ibis (Nipponia nippon) in Korea

The Oriental White Stork (Ciconia boyciana) and the Crested Ibis (Nipponia nippon) are wetland species listed as “Endangered” on the IUCN Red List of Threatened Species. The two species were once common on the Korean peninsula, but have experienced a severe population reduction in the past decades. Currently, they are officially extinct in Korea. At present, reintroduction programs to release the birds to the wild are in progress in Korea as well as in Japan. In this study, we surveyed the historic breeding sites of the two species using the literature and face-to-face interviews with local people as a step toward determining appropriate breeding habitats for reintroduction. We found 26 historic breeding sites for the Oriental White Stork in Chungcheong-do and Gyeonggi-do, but did not find any breeding sites for the Crested Ibis. These findings suggest that the Oriental White Stork was resident, while the Crested Ibis was a winter visitor to Korea. Based on these results, we discuss the possibilities for successful reintroduction of the two species in Korea.

Abundance and Breeding Migration of the Asian Toad (Bufo gargarizans)

We monitored a breeding population of the Asian toad (Bufo gargarizans), in the Wonheunge pond at Sannamdong, Chungju, from 5 March to 11 April, 2006 and 14 February to 31 March, 2007 to investigate their movement patterns, breeding population sizes, and physical characteristics. Terrestrial migration to the pond started on 5 March in 2006 and 14 February in 2007. We captured a total of 266 immigrating individuals (213 males, 53 females) in 2006 and 307 (222 males, 85 females) in 2007, and found 50 adults apparently killed by motor vehicles while migrating to the pond in 2007. Emigration from the pond to terrestrial sites started on 15 March 2006 and 5 March 2007. We captured a total of 245 emigrating toads (181 males, 65 females) in 2006 and 99 (92 males, 7 females) in 2007. An additional 10 emigrating adults were found dead on the road. During both the immigration and emigration periods, two peaks in capture frequency appeared for each sex in each breeding season. The immigration peaks corresponded with higher temperatures, while the emigration peaks corresponded with high humidity. Migrating Asian toads showed sexual size dimorphism and a male-biased sex ratio. Body weights and SVL (snout-vent length) of immigrating and emigrating individuals were negatively related with migration dates.

Distribution of Fish and Amphibian in Rice Fields Near the Yedang Reservoir in Korea1

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.

Use of the foraging area by captive bred oriental storks (Ciconia boyciana) in a closed semi natural paddy field

Rice paddy fields have been recognized as an alternative habitat for avian wetland foragers, and fish-rice farms have become a new tool in improving the abundance of aquatic animals. However, the use of the habitats by avian foragers, particularly by oriental storks (Ciconia boyciana), was not well understood. In the present study, we investigated how a fish-rice farm influenced the abundance of aquatic animals and documented the foraging behavior of the two captive bred oriental storks in a closed semi-natural paddy field. Our results showed that the fish refuge pond (water depth 40 cm) had a higher abundance of fish whereas the areas planted with rice (water depth 20 cm) had more tadpoles and some aquatic insects. The two captive bred oriental storks captured mostly fish and aquatic insects in the rice-planted area and mostly fish in the fish refuge pond. The two oriental storks had higher foraging success and spent more time for foraging in the rice-planted area than in the fish refuge pond. This result suggests that the oriental storks might prefer foraging in the area with fish, aquatic insects, and amphibians under a greater success rate presumably due to shallow water depth in the paddy fields with a fish-rice farm.