• Journal of Ecology and Environment
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• 제43권2호
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• pp.104-116
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• 2019

Background: The composition of wild bird populations in temperate zones greatly varies depending on phenological changes rather than other environmental factors. Particularly, wild birds appearing in wetlands fluctuate greatly due to the crossover of species arriving for breeding during the summer and for wintering. Therefore, to understand the changes to species composition related to phenology, we conducted this basic analysis of populations to further the cause of the protection of wetland-dependent wild birds. Methods: It is wrong to simply divide a wild bird population investigation into seasons. This study identifies species composition and indicator species that change along with seasons. Wetlands to be surveyed are protected by natural monuments and wetland inventory and are in a state close to nature. In order to identify as many species as possible in wetlands, a survey was conducted in both shallow and deep wetlands. The water depth varied in these areas, ranging from 0.2 to 2.0 m, allowing for both dabbling and diving ducks to inhabit the area. Surveys were conducted using line-transect and distance sampling methods and were conducted at intervals of 2 weeks. The survey was conducted under the following three categories: the eco-tone and emergent zone, the submergent zone, and the water surface. The survey was conducted along a wetland boundary by observing wild birds. A PC-ord program was used for clustering, and the SAS program was used to analyze the changes in species composition. The data strongly indicates that day length is the main factor for seasonal migration periods, despite the fact that climate change and increasing temperatures are often discussed. Results and conclusions: The indicator species for determining seasons include migrant birds such as Ardea cinerea, Alcedo atthis, Anas penelope, and Poiceps ruficollis, as well as resident birds such as Streptopelia orientalis and Emberiza elegans. Importantly, increases in local individual counts of these species may also serve as indicators. The survey results of seasonal fluctuations in temperate zones shows that spring (April to June), summer (July to September), autumn (October), and winter (November to March) are clearly distinguishable, even though spring and summer seasons tend to overlap, leading to the conclusion that additional research could more clearly identify fluctuation patterns in species composition and abundance in the study area.

• 한국환경생태학회지
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• 제33권1호
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• pp.16-27
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• 2019

습지의존종이면서 습지생태계의 질적 변화를 파악할 수 있는 지표종인 잠자리목의 조사 시기를 제안하고자 산청군내 7개소의 인공습지를 대상으로 2015년 5월부터 2016년 10월까지 2주 간격으로 총 29회에 걸쳐 잠자리 종과 개체수를 조사하였다. 1~3월과 11월, 12월에는 잠자리목이 관찰되지 않아 조사 시기에서 제외하였다. 군집을 분류한 결과, 4~6월, 6~8월, 9~10월이 각각 다른 군으로 분류되었으나 4월, 6월, 10월의 경우 강우, 기온 등의 영향으로 연도별 변화가 예상되어 조사 시기를 대표할 수 없었다. 따라서 온대 지역의 잠자리 조사 시기에는 5월, 7~8월, 9월이 필수적으로 포함되어야 할 것으로 판단되었다. 종의 변화는 봄철에는 참실잠자리, 등검은실잠자리가, 여름철에는 고추잠자리, 등검은실잠자리, 먹줄왕잠자리, 배치레잠자리, 큰밀잠자리 등이, 가을에는 큰청실잠자리, 흰얼굴좀잠자리 등의 출현빈도가 높아지는 경향을 나타내었다.

• 한국환경생태학회지
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• 제34권6호
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• pp.515-529
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• 2020

인공습지는 조성 후 자연적인 천이 과정으로 인해 육상식물의 비율이 높아지는 등 생물학적 및 물리적인 변화가 진행되는데, 이는 정화 기능 뿐만 아니라 종다양성에도 영향을 미칠 수 있다. 이에 본 연구는 낙동강 매수토지 중 수심, 주변 입지 조건 등을 고려하여 7개의 인공습지를 선정한 후 물리적인 환경 및 생물종의 시계열적인 변화를 모니터링한 결과를 바탕으로 생물다양성에 영향을 미치는 환경요인을 도출하고 관리방안을 제안하고자 하였다. 서식처와 종다양성의 변화 경향을 예측하고자 환경현황과 습지의존종인 잠자리목의 출현 현황을 파악하였다. 수심 0.2~1m 내외로 복원되어 수면이 유지되었던 2012년과 비교하여 2015년에는 식재된 추수식물이 깊은 수심으로 확산되면서 개방 수면의 면적도 줄었다. 잠자리의 종수는 총 54종류가 관찰되었는데 식재한 식물이 확산되었음에도 불구하고 식생, 수면, 초지 등 서식처 다양성이 유지되어 조성 초기와 유사하였다. 하지만, 잠지리의 개체수는 2012년과 비교하여 2015년에 줄었는데, 이는 수면이 축소되면서 수생식물이 드문 곳을 선호하는 실잠자리과에 속하는 종의 개체수가 감소하였기 때문인 것으로 판단되었다. 연도별 습지간 종수 및 개체수의 차이를 분석한 결과 p-value가 각각 2.568e-09, 1.162e-08로 차이는 유의하였다. 개방 수면 감소가 종다양성과 잠자리의 서식밀도에 가장 큰 영향을 미치는 것으로 분석되었는데, 조성 초기에 식재한 갈대, 달뿌리풀, 부들 등 추수식물의 확산이 개방 수면 축소와 잠자리 종수 감소를 초래하므로 개방 수면을 유지하는 관리가 이루어져야 할 것이다.

• 한국습지학회지
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• 제10권1호
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• pp.39-47
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• 2008

환경친화적 수자원 관리의 대안으로 대두되고 있는 천변저류지는 일차적인 홍수조절의 목적과 부차적인 생태공원으로서의 가치로 인하여 조성을 위한 기술개발과 함께 생태학적 계획기준이 시급하게 요청되고 있다. 본 연구는 생태 천변저류지의 조성과정에서 요구되는 목표 생물종과 서식환경의 조성 등 생태학적 계획기준을 제시하기 위하여 수행되었다. 연구대상지는 국가차원의 천변 저류지 조성이 검토되고 있는 임진강 석장천 합류지역으로 하였고, 유사한 생태적 입지조건을 지닌 남한강 홍수터 지역을 대조지로 선정하였다. 식생과 어류상 및 조류상을 중심으로 생태특성을 조사분석한 결과 식생군집은 버드나무와 갯버들, 물억새, 갈대 등의 우점 군락이 대표적으로서 개방수역과 사주부, 경작지 등과 함께 물리적 기반환경을 형성하였고, 어류상은 잉어과 어종과 납자루과 어종이 대표적이었으며, 조류상은 물새류인 오리류와 주연부종인 붉은머리오목눈이가 우점종이었다. 생태 천변 저류지의 생태-수문조건은 습지형을 지배적인 유형으로 호소형과 육상형이 부분적으로 결합한 복합 습지모형이 적합할 것으로 판단되었으며, 이를 바탕으로 생태특성 분석결과에 기초하여 어류의 경우 납자루과와 잉어과 어종, 조류의 경우 봄철은 백로류, 겨울철은 오리류를 목표 생물종으로 설정하였다. 또한 이들 목표 생물종의 번식지 및 산란처, 섭식 및 취식장소, 먹이원, 휴식지, 피난처, 치어 서식처, 잠자리 등 일반적인 서식환경을 고려한 구체적인 서식처 조성의 계획기준을 제시하였다.

• Animal cells and systems
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• 제16권3호
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• pp.260-267
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• 2012

Calling behavior is often used to infer breeding patterns in anurans. We studied the seasonal and diel calling activities of anuran species in a wetland in central Korea to determine the calling season and to evaluate the effects of abiotic factors on male calling. Acoustic monitoring was used in which frog calls were recorded for a full day, once a week, throughout an entire year. Using acoustic monitoring, we identified three frog species in the study site. Males of Rana dybowskii called in late winter and early spring; we thus classified this species as a winter/spring caller. The results of binary logistic regression showed that temperature, relative humidity, and 1-day lag rainfall were significant factors for male calling in R. dybowskii. Temperature and relative humidity were important factors for the calling activity of R. nigromaculata, whereas 24-h rainfall and 1-day lag rainfall were not significant. Thus, we determined R. nigromaculata to be a summer caller independent of weather. In Hyla japonica, relative humidity, 24-h rainfall, and 1- day lag rainfall were significant for male calling, suggesting that this species is a summer caller dependent on local rain.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.461-468
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• 2019

Background: This study aimed to identify NO₃^--N sources using the stable isotope δ¹⁵N in Chydorus sphaericus (OF Müller), to investigate hydrological characteristics and nutrient states in artificial wetlands near the Nakdong River. Chydorus sphaericus is dominant in wetlands where aquatic plants are abundant, occurring in high density, and is sensitive to wetland water pollution, making it suitable for identification of NO₃^--N sources. Results: NO₃^--N sources for each wetland were strongly dependent on hydrological characteristics. Wetlands with sewage or rainfall/groundwater as their main sources had high levels of NO₃^--N, whereas wetlands with surface water as their main input had comparatively lower levels. Since wetlands with sewage and rainfall/groundwater as their main water sources were mostly detention ponds, their inputs from tributaries or the main river stream were limited and nutrients such as NO₃^--N easily become concentrated. Changes in NO₃^--N levels at each wetland were closely associated with δ¹⁵N of C. sphaericus. Interestingly, regression analysis also showed positive correlation between δ¹⁵N of C. sphaericus and NO₃^--N level. Conclusions: We conclude that the nitrate stable isotope (δ¹⁵N) of C. sphaericus can be used to elucidate the hydrological characteristics of riverine wetlands. This information is important for maintenance and conservation of artificial wetlands at the Nakdong River.

• Journal of Ecology and Environment
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• 제46권1호
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• pp.1-7
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• 2022

Background: In this study, we proposed that the population dynamics of non-native red-eared sliders (Trachemys scripta elegans) depends on the species' habitat extension and survivorship. We used a logistic equation with time-dependent habitat carrying capacity. In detail, the present carrying capacity depends on the red-eared slider population of the previous year. Anthropogenic activities such as the abandonment of previously captive red-eared sliders or the release due to religion customs would supply new habitats to the species. Therefore we assumed that anthropogenic spread increases the habitat carrying capacity. Based on the urbanization increase rate of 3% in Korea from 1980 to 2000, we assumed an annual spread of 3% to simulate the population dynamics of the red-eared slider. In addition, the effect on the population of an increase of natural habitats due to migration was simulated. Results: The close relationship between the distributions of non-native red-eared sliders and of urbanized areas demonstrates that urbanization plays an important role in providing new habitats for released individuals. Depending on the survivorship, the population of the red-eared slider in Korea increased 1.826 to 3.577 times between 1980 and 2000. To control population growth, it is necessary to reduce carrying capacity by reducing habitat expansion through prohibition of release into the wild ecosystem and careful managements of the wetland or artificial ponds. Changes in the habitat carrying capacity showed that the population fluctuated every other year. However, after several years, it converged to a consistent value which depended on the survivorship. Further, our results showed that if red-eared sliders expand their habitat by natural migration, their population can increase to a greater number than when they have a 99% survivorship in a fixed habitat. Conclusions: Further introductions of red-eared sliders into wetlands or artificial ponds should be prohibited and managed to prevent future spread of the species. Moreover, it is important to reduce the species' survivorship by restoring disturbed ecosystems and maintaining healthy ecosystems.