• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.567-578
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• 2022

Various social and environmental problems have recently emerged due to global climate change. In South Korea, coniferous forests in the highlands are decreasing due to climate change whereas the distribution of subtropical species is gradually increasing. This study aims to respond to changes in the distribution of forest species in South Korea due to climate change. This study predicts changes in future suitable areas for Pinus koraiensis, Cryptomeria japonica, and Chamaecyparis obtusa cultivated as timber species based on climate, topography, and environment. Appearance coordinates were collected only for natural forests in consideration of climate suitability in the National Forest Inventory. Future climate data used the SSP scenario by KMA. Species distribution models were ensembled to predict future suitable habitat areas for the base year(2000-2019), near future(2041-2060), and distant future(2081-2100). In the baseline period, the highly suitable habitat for Pinus koraiensis accounted for approximately 13.87% of the country. However, in the distant future(2081-2100), it decreased to approximately 0.11% under SSP5-8.5. For Cryptomeria japonica, the habitat for the base year was approximately 7.08%. It increased to approximately 18.21% under SSP5-8.5 in the distant future. In the case of Chamaecyparis obtusa, the habitat for the base year was approximately 19.32%. It increased to approximately 90.93% under SSP5-8.5 in the distant future. Pinus koraiensis, which had been planted nationwide, gradually moved north due to climate change with suitable habitats in South Korea decreased significantly. After the near future, Pinus koraiensis was not suitable for the afforestation as timber species in South Korea. Chamaecyparis obtusa can be replaced in most areas. In the case of Cryptomeria japonica, it was assessed that it could replace part of the south and central region.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.811-822
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• 2019

Environmental flows in the downstream sections of Yongdam Dam, Wonju Stream Dam, and Hongcheon River were estimated with selected target fish species such as Nigra for the site of Yongdam Dam, Splendidus for the site of Wonju Stream Dam, and Signifer for the site of Hongcheon River by considering endangered and domestic species. Physical habitat analysis was performed to estimate environmental flows for the study sites by applying the Physical Habitat Simulation (PHABSIM) and RIVER2D which combined hydraulic and habitat models. Based on the monitored data for ecological environment, the Habitat Suitability Index (HSI) for the target species was estimated by applying the Instream Flow and Aquatic Systems Group (IFASG). In particular, based on the result of fish monitoring, the HSI for each stage of the growth for target species was analyzed. As a result, the Weighted Usable Area (WUA) was maximized at $4.9m^3/s$ of flow discharge during spawning, $5.8m^3/s$ during the period of juvenile, and $8.9m^3/s$ during the adult fish season at the downstream section of Yongdam Dam. The result of the Wonju Stream Dam showed an optimal environmental flow of $0.4m^3/s$, $1.0m^3/s$, and $1.5m^3/s$ during the period of spawning, juvenile, and adult. The habitat analysis for the site of Hongcheon River, which is a non-regulated stream, produced an optimum environmental flow of $5m^3/s$ in the spawning period, $4m^3/s$ in the juvenile stage and $6m^3/s$ in the adult stage.

• Ecology and Resilient Infrastructure
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• v.2 no.1
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• pp.64-79
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• 2015

We investigated the tidal current, hydrographic data, and benthic environment of major sea cucumber (Holothuroidea, de Blainville, 1834) habitats in Baengnyeongdo, Jindo and Uljin to understand the optimal environmental or ecological habitat for sea cucumbers. The three study areas were characterized by a cold-water mass of temperatures ranging $12{\sim}18^{\circ}C$, with an active circulation between the surface and deep waters. According to an analysis of the tidal current map, a strong flow velocity of $100{\sim}120cm\;s^{-1}$ appeared in Baengnyeongdo and Jindo. The three sea cucumber habitats showed the common characters of a bottom sediment composed of sand-silt, a diverse seaweed colony and benthic organisms, and boulders and rocks which provide a hideout for the organisms. We aimed to draw the optimal habitat condition for sea cucumbers in Korea, and the result showed that the low water temperature, rapid water flow, active vertical mixing between surface and deep waters, bottom composed by sand-silt, large rocks, and diverse seaweed colony and benthic organism were important factors. The optimal habitat for Juvenile sea cucumbers was the intertidal areas characterized by a muddy bottom, reef, and seaweed. The optimal habitat for adult sea cucumbers was characterized by a place where sand and mud are mixed, and the body size of the sea cucumber was proportional to water depth, and the relatively large boulders and rocks compared to the intertidal area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5B
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• pp.331-343
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• 2012

In this study, the site investigation for fish was performed in the 15 km of Hongcheon river including Oancheon stream. The river ecosystem health was evaluated using the field data for fish. The field survey was carried out at 9 sites, 4 times from August to November 2011. The ecological diversity, including dominance, evenness, and richness and the ecological health using IBI and QHEI were evaluated. The result shows that the mean IBI in the 9 sites is in good-common condition, but the downtown section has a common-worse condition. The result evaluated by QHEI shows optimum-good condition. Also, the habitat suitability index for Pseudopuntungia tenuicorpa, which is one of endangered species, was evaluated, and then the environment flow was calculated by using the PHABSIM model. The previous research in the literature reports that Acheilognathus signifer, one of the endangered species, inhabited in Hongchen river. However, the existence of Acheilognathus signifer was not found in the recent research and this study. Thus, the physical habitat condition for Acheilognathus signifer was evaluated using the field data in the previous study. Also, the habitat improvement for Acheilognathus signifer in Hongcheon river was proposed.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.7-7
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• 2017

범람파동 개념에 따르면 하도와 홍수터의 횡적 연결성은 하천 생태계의 생물다양성과 생산성 증대에 중요한 역할을 한다. 제방에 의하여 제내지 홍수터가 하도와 차단된 우리나라 하천에서 생태적 서비스를 증대하기 위해서 횡적 연결성을 복원하는 기술 개발이 필요하다. 횡적 연결성의 복원 기술을 개발하기 위해서는 우선 하도와 홍수터 사이에 생태적 연결성의 현황을 파악하고 연결성을 저해하는 요인을 진단하는 평가 기술 개발이 시급히 요청되고 있다. 따라서 본 연구에서는 제방에 의하여 차단된 제내지 하천환경에서 수리적, 생태적 횡적 연결성을 평가하고 진단하는 기술을 개발하고 연결성 회복 방안을 제안하고자 한다. 차단된 제내지 하천환경 평가는 1) 지리정보시스템을 이용하여 차단된 하천공간을 탐색하고, 2) 탐색된 전체 재내지에서 원격평가에 의하여 간편하게 횡적 연결성 평가를 실시하고, 3) 선정된 특정 제내지 대상지에서 현장평가에 의하여 상세하게 연결성을 평가하는 순서로 수행된다. 차단된 하천공간의 획정은 홍수가 범람할 수 있는 제내지 공간을 잠재적 하천공간으로 정의하고 수치표고모델 (DEM)과 하천기본계획의 30년 빈도 홍수위 자료를 이용하여 제내지 홍수터를 탐색하였다. 제내지 홍수터의 원격 연결성평가는 지리정보시스템에서 수치지도와 토지피복도 등 공간자료를 이용하여 수리 및 서식처 환경성, 제방 차단성과 하도 및 육상 연결성을 평가하고 원격평가 결과를 토대로 현장평가 대상지를 선정하였다. 횡적 연결성의 현장평가를 위하여 크게 하도-홍수터 연결성과 제내지 서식처 보존성으로 평가 항목을 선정하였다. 또한 연결성 평가는 수리연결성과 생물연결성으로, 서식처 보존성 평가는 습지유지율, 습지보존성, 육역지보존성을 세부항목으로 구성하였다. 평가 항목별로 5 등급의 평가 기준에 따라서 평가 점수를 부여하고 평가 총점을 산출하여 최종 연결성 평가 등급을 5 단계로 구분하였다. 현장평가를 위한 MS Access 기반 소프트웨어를 개발하여, 데이터 입력과 관리 및 평가 결과 산출과 비교를 편리하게 하였다. 개발된 제내지 하천환경 평가법을 청미천과 만경강에 적용하여 검증하였다. 개발된 평가법을 바탕으로 차단된 제내지 하천환경에서 연결성 회복에 따른 어류와 식생의 분포를 예측하는 수리생태 결합모델을 개발하였다. 먼저 차단된 제내지에서 연결 수로를 복원하여 유속, 수심 분포를 준이차 수리수문 모델로 예측하였다. 예측된 수리 환경에 따라서 지표어종의 서식처 적합도 지수 (HSI)를 이용하여 서식 분포 확률을 모의하였다. 또한 일반화가법모델 (GAM)을 이용하여 환경구배에 의한 우점식생의 분포를 예측하였다. 차단된 제내지 하천환경의 생태적 연계성 평가 기술을 기반으로 제방제거, 제방후퇴, 제방고 하강, 수문 및 연결수로 개선, 생물이동 저해 장벽 제거 등의 다양한 복원기술이 개발되어야 할 것으로 생각된다.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.285-293
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• 2016

This study conducted the evaluations of stable channel and physical disturbance improvement for optimal construction of river structures by focusing on Wonju River. A stable slope was analyzed sectionally for stable channel design, and in order to satisfy the stable slope, river structure improvement scenarios were deduced. Accordingly, through physical disturbance improvement evaluation for each scenario, the study extracted the optimal scenario for stable channel design and physical disturbance improvements. The changes in physical habitat were analyzed when river structure improvements were made for stable channel design and physical disturbance improvement. Zacco koreanus, an indicator fish of the soundness of the aquatic ecosystem, was selected as a restoration target species by investigating the community characteristics of fish fauna and river environments in the Wonju River. The habitat suitability was investigated by the PHABSIM model with the habitat suitability index of Zacco koreanus. The results of the prediction evaluation showed a slight decrease in habitat suitability and weighted usable area. However, it was not influenced by the improvements in the river structure. The study suggested river structure arrangement methods that can improve physical soundness and safety of Wonju River, and confirmed that there were no effects to the changes in the physical habitat.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.73-75
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• 2018

최근의 하천복원 사업은 제외지 중심의 하천복원에서 벗어나 제내지의 격리 차단된 구하도까지 복원하고자 하는 노력이 시도되고 있다. 그러나 하천복원에 따른 수리적 및 생태적 연결성 향상이 적절히 수행되는지에 대한 정량적 평가 수단이 부족한 상태다. 본 연구에서는 구하도 복원에 따른 생태적 연결성 평가수단으로서 복원전 후 수리해석 결과를 이용하여 대상어종의 서식처적합도지수(HSI)와 식생의 공간분포를 분석 또는 예측할 수 있는 모형을 개발하였다. 공간분포된 수리특성을 위해서는 2 3차원의 모형이 필요하지만 복잡한 계산과정, 고도의 기술 및 많은 시간과 비용이 필요하다는 점에서 접근이 용이하지 않다. 이에 1차원 홍수추적모형의 결과를 이용하여 1차원 수리특성을 2차원으로 확장시키는 수치모형도 함께 개발하였다. 다만 개발된 각 모형의 단계별 실행 결과는 개별적인 요소의 평가로서 그 의미가 작으므로 하천복원의 종합적 평가를 위한 수리-물리서식처-식생의 통합적 모의가 필요하다 개발된 모형의 사용성 증대 및 생태적 연결성 평가 통합모형으로의 발전을 위해 개발된 모형을 하나의 연동시스템으로 구축하고자 하며, 연동 시스템을 이용하여 수리적 및 생태적 연결성을 신속하고 간단하게 해석할 수 있다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.195-205
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• 2020

Oceanic conditions in walleye pollock habitat in the East Sea have shown decadal fluctuations between warm and cold periods in turn. Specifically, sea surface temperature (SST) has shown a dramatic increase between the late 1980s and the middle 2000s, and abrupt decreasing patterns after the late 2000s. Oceanic conditions in the Dong-han Bay (spawning ground) and middle eastern coastal waters (fishing ground), however, indicated different fluctuation trends in SST, increasing in the Dong-han Bay after the late 1980s, and decreasing after the late 2000s. These fluctuation patterns were especially clear in February and March. Sea surface temperature in the middle eastern coastal waters of Korea soared continuously after the late 1980s, but did not show a distinct decreasing pattern after the late 2000s compared with Dong han Bay, except for February SST values. These long term water temperature changes in both walleye pollock spawning and fishing ground are related to variation in walleye pollock landings. Especially, abrupt changes in spawning ground SST can be one of the factors influencing survival in the early ontogenesis of walleye pollock, including egg and yolk larval stages. During the 1980s, the area of suitable spawning temperature (2-5℃) was wider, and the length of Walleye pollock egg and larval stages greater compared with past and present oceanographic environments. However, such patterns did not correspond with the optimal spawning temperature range and greater length of development of walleye pollock during the late 1980s likely triggering a decline in pollock stock. In conclusion, it has been supposed that the dramatic decrease in walleye pollock landings in the East Sea since the late 1980s was caused by increasing water temperature leading to both early mortality and unsuitable spawning conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.24-28
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• 2016

댐의 발전방류는 댐 하류의 하천에 비정상성이 큰 흐름을 발생시킨다. 이와 같은 흐름은 하류 하천의 수심 및 유속 조건을 급격하게 변화시키게 되어 어류 물리서식처에 큰 영향을 끼치게 된다. 또한 갑작스런 유량의 상승은 어류를 하류로 강제로 이동시키며, 빠른 수위의 하강은 어류를 하안에 고립되게 하여 죽음을 초래하게 된다. 발전방류가 어류 물리서식처에 미치는 영향을 평가한 기존의 연구는 대부분 흐름계산을 위하여 준정류 모형을 사용하였다. 하지만 준정류 모형은 발전방류와 같은 비정상성이 큰 흐름에 대하여 적절히 모의하지 못하는 한계가 있다. 본 연구의 목적은 2차원 부정류 모의가 가능한 River2D 모형을 이용하여 댐 하류 하천에서의 발전방류가 어류 물리서식처에 미치는 영향을 분석하는 것이다. 연구 대상지역은 괴산댐 하류 지점인 수전교부터 대수보까지 2.3 km 구간이다. 서식처모형은 피라미에 대한 HSI 모형을 사용하였다. 복합서식처 적합도 지수, 하상전단응력을 모의하였으며 소와 여울의 지형조건에서 발전방류가 위의 인자들에 미치는 영향에 대하여 분석하였다. 또한 발전방류량이 발생하였을 때 기저유량의 조건에 따라 어류 물리서식처에 미치는 영향에 대하여 분석하였다.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.433-442
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• 2017

As a result of the Four-River Restoration Project in Korea, the habitat of endangered plant species of Aster altaicus var. uchiyamae and Polygonatum stenophyllum, which had been natively grown in the riparian zone of Namhan River, was destroyed and artificial replacement habitats were created. In this study, Habitat Suitability Index (HSI) was used to determine whether the replacement habitats are suitable for each species or not. From October 2015 to July 2016, Habitat Evaluate Procedures (HEP) were conducted on two replacement habitats of A. altaicus var. uchiyamae (Gangcheonsum and Sum-River) and on two replacement habitats of P. stenophyllum (Gangcheonsum and Youngjuk) in the Namhan River watershed. As evaluation parameters for A. altaicus var. uchiyamae habitat, habitat matrix (ratio of unburied gravel), height above the ordinary water level, soil nutrients, and light conditions were selected and for P. stenophyllum habitat, soil texture, light conditions, and coverage of companion species were selected. HSI was applied to evaluate the suitability of each replacement habitat. According to the result of the evaluation, replacement habitats of A. altaicus var. uchiyamae and P. stenophyllum located in Gangcheonsum have relatively high HSI values as 0.839 and 0.846, respectively. On the other hand, replacement habitats of A. altaicus var. uchiyamae in Sum-River and P. stenophyllum in Youngjuk zone have HSI value of 0, indicating unsuitable habitats for these species. This is the first attempt to apply HSI for plant species in Korea and proved the usefulness of HSI on plants.