• Korean Journal of Agricultural Science
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• v.30 no.1
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• pp.41-58
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• 2003

This study was conducted to investigate bird community and to suggest a proper way how to manage protect bird community in Gap stream. The survey was carried out over four sections by the line transect method and point counts method from September 2001 to August 2002. Natural stream region as Gasuwon Bridge - Mannyeon Bridge are observed birds were 11 orders 29 families 67 species, Artificial stream region as Mannyeon Bridge - Daedeok Bridge are observed birds were 6 orders 10 families 30 species, Daedeok Bridge - Wonchon Bridge are 8 orders 12 families 28 species, Wonchon Bridge - Gap Stream Bridge are 8 orders 18 families 40 species. All the observed birds in artificial stream region are 8 orders 19 families 47 species. Number of species in natural stream region was higher than artificial stream region owe to a various habitat environment such as forest, cultivated land, streamside forest, sandy plain, gravelly field, reedy field etc. and can not add with the interface and the usage of the human. Number of species in artificial stream region was lower than natural stream region owe to a simple habitat environment and the water ecosystem is severed with embankment block and grass plot with the land ecosystem. The furtherance of various habitat environment which considers the ecosystem like the natural stream as the water ecosystem is joined together with the land ecosystem is desired to attract various wildbirds in Gap stream. The design is desired with the maintenance of the stream to consider the stream corridor which plays ecological important role as connect the fragment habitats.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.894-905
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• 2010

A habitat evaluation method was used to estimate the optimum suitability of the study area for the target algae. Habitat evaluation was carried out using an habitat evaluation procedure (HEP) so that the optimum suitability was quantitatively estimated for carrying out marine afforestation in the study area. According to the results of the suitability analysis, the variation of light and wave conditions according to depth showed the factors with the largest impact to involve the spatial distribution of suitable locations within the area. The total suitable area selected was calculated to be 18ha. The quality of the target algae (Ecklonia cava Kjellman) habitat was analyzed using an habitat suitability index (HSI) model of the HEP, which showed 0.55-0.907 (the maximum value being 1.0). This indicated that artificial reefs for afforestation should be installed to zonation type because the suitable area selected (The HSI value was 0.55~0.907) was distributed within the same depth line.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.418-425
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• 2012

Dam construction in a river can change its hydrological pattern and trap sediments, which results in ecological changes in the downstream. It is a common phenomenon in the downstream of dams to have decreased sediment flow and increased periphyton. Artificial floods and sediment application are suggested as mitigation practices in order to simulate natural process of flood; transporting sediment and sloughing periphyton off. In this study the effects of artificial floods on periphyton were examined by applying sand artificially and discharging water from a dam (Yangyang Dam, Korea). The study area has been suffering from turbidity problems caused by shore erosion of the dam. The accumulation of inorganic sediments and increase of periphyton on the river bottom are the major factors of habitat deterioration in the downstream reaches. Artificial flood and artificial addition of sand was performed in summer and the effects were measured. Piles of applied sands were washed off easily by discharge and it enhanced the periphyton sloughing effect. The removal efficiency of periphyton was 50 ~ 80% within the 2 km reach from the dam. In conclusion artificial floods and sand application can be a good mitigation measure for the habitat rehabilitation after a dam construction in streams.

• Journal of Ecology and Environment
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• v.46 no.1
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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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.6
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• pp.67-84
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• 2023

In some areas of the Republic of Korea, the designation and management of conservation areas do not adequately reflect regional characteristics and often impose behavioral regulations without considering the local context. One prominent example is the Busan EDC area. As a result, conflicts may arise, including large-scale civil complaints, regarding the conservation and utilization of these areas. Therefore, for the efficient designation and management of protected areas, it is necessary to consider various ecosystem factors, changes in land use, and regional characteristics. In this study, we specifically focused on the Busan EDC area and applied machine learning techniques to analyze the habitat of regional species. Additionally, we employed Explainable Artificial Intelligence techniques to interpret the results of our analysis. To analyze the regional characteristics of the waterfront area in the Busan EDC district and the habitat of migratory birds, we used bird observations as dependent variables, distinguishing between presence and absence. The independent variables were constructed using land cover, elevation, slope, bridges, and river depth data. We utilized the XGBoost (eXtreme Gradient Boosting) model, known for its excellent performance in various fields, to predict the habitat probabilities of 11 bird species. Furthermore, we employed the SHapley Additive exPlanations technique, one of the representative methodologies of XAI, to analyze the relative importance and impact of the variables used in the model. The analysis results showed that in the EDC business district, as one moves closer to the river from the waterfront, the likelihood of bird habitat increases based on the overlapping habitat probabilities of the analyzed bird species. By synthesizing the major variables influencing the habitat of each species, key variables such as rivers, rice fields, fields, pastures, inland wetlands, tidal flats, orchards, cultivated lands, cliffs & rocks, elevation, lakes, and deciduous forests were identified as areas that can serve as habitats, shelters, resting places, and feeding grounds for birds. On the other hand, artificial structures such as bridges, railways, and other public facilities were found to have a negative impact on bird habitat. The development of a management plan for conservation areas based on the objective analysis presented in this study is expected to be extensively utilized in the future. It will provide diverse evidential materials for establishing effective conservation area management strategies.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.1-11
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• 2020

This study aimed to develop the HSI (Habitat Suitability Index) model of Cypripedium guttatum. and to verify this model by applying to the candidate sites for replacement habitat. The development of HSI and SI (Suitability Index) model was conducted based on the existing literature, field surveys, and expert opinions for information on ecological habitat characteristics. Seven variables were selected as habitat variables including mean maximum temperature in Jul.-Aug., lighting, slope, altitude, effective soil depth, soil texture, and artificial overexploitation (i.e. protected areas). HSI model was developed for C. guttaum based on these variables. This HSI model showed high applicability to selection and evaluation of replacement habitats for C. guttaum. Our findings could provide the basic information on habitat assessment to prevent the extinction of endangered C. guttatum. However, since there is a limitation that the survey data were insufficient, further field surveys should be conducted on several habitat types to improve the accuracy of the HSI model.

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.142-150
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• 2021

To analyze the distribution characteristics of alien plants in various habitat types, 249 sites were selected from four administrative districts in the Gyeongsang region of Korea. The survey was conducted across nine different habitat types. A total of 115 species of alien plants were collected; comprising 23 families, 73 genera, 112 species, and 3 varieties. Species from the family Compositae were the most common at 33.0%. Raunkiaer's life forms had the highest occurrence rate with 70 species(60.9%) of therophytes(Th) followed by 30 species (26.1%) of hemicryptophytes (H) and 8 species (7.0%) of geophytes (G). The distributions of alien plant species per habitat type were: 81 species on the roadside; 80 species on vacant lots and artificial habitats; 67 species in streams; 53 species in grasslands; 47 species in cultivated lands; and 39 species on the coast. Since 2017, the number of alien plants has increased in Gyeongju-si, Cheongdo-gun, and Pohang-si, and decreased in Ulsan Metropolitan-si. In each region, 614 taxa were observed. The invasive alien species, Sicyos angulatus, Hypocaeris radicata, and Solanum carolinense, were observed for the first time and are expected to further increase the disturbance of the ecosystem.

• Journal of Korean Society on Water Environment
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• v.23 no.3
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• pp.348-355
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• 2007

We investigated temporal changes of composition, habitat area, growth rate and elements content of hydrophytes at the artificial vegetation island (AVI) in Kyungan Stream within Lake Paldang. We also assessed nutrient removal rate through cutting off the emergent part of hydrophytes. The kinds of hydrophytes have increased from four species (P. australis, P. japonica, T. angustifolia and the Z. latifolia) at initial stage of installation to more than 29 species for 6-year operation. P. japonica was most dominant species at the AVI in 2006. The habitat area of have increased about 2.5 times compared to the initial planting area, occupying 63% of AVI's vegetation area. The incoming species of S. fluviatilis and B. frondosa have adapted successively and expanded habitat area in the AVI. The relative growth rate of P. japonica and P. australis was highest in spring sprouting period. Their hights and weights have increased until summer, by the time they were cutting off the emergent part. They started regrowth immediately after cutting and continued to grow until September and withered away in November. The carbon contents of P. japonica and P. australis have increased during growth phase, on the contrary, the nitrogen and phosphorus contents have decreased. By cutting off and removing the emergent part (leaves and branches) of hydrophytes twice from AVI, $17.6gN/m^2/y$ of nitrogen and $1.3gP/m^2/y$ of phosphorus was removed from AVI in 2006.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.28-38
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• 2008

The purpose of this study are to compare existing presence-absence predictive models and to predict suitable habitat for Goral (Nemorhaedus caudatus raddeanus) that is an endangered and protected species in Seoraksan national park using the best model among existing predictive models. The methods of this study are as follows. First, 375 location data and 9 environmental data layers were implemented to build a model. Secondly, 4 existing presence-absence models : Generalized Linear Model (GLM), Generalized Addictive Model (GAM), Classification and Regression Tree (CART), and Artificial Neural Network (ANN) were tested to predict the Goal habitat. Thirdly, ROC (Receiver Operating Characteristic) and Kappa statistics were used to calculate a model performance. Lastly, we verified models and created habitat suitability maps. The ROC AUC (Area Under the Curve) and Kappa values were 0.697/0.266 (GLM), 0.729/0.313 (GAM), 0.776/0.453 (CART), and 0.858/0.559 (ANN). Therefore, ANN was selected as the best model among 4 models. The models showed that elevation, slope, and distance to stream were the significant factors for Goal habitat. The ratio of predicted area of ANN using a threshold was 31.29%, but the area decreased when human effect was considered. We need to investigate the difference of various models to build a suitable wildlife habitat model under a given condition.

• Korean Journal of Environment and Ecology
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• v.19 no.3
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• pp.279-286
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• 2005

This study was conducted to analyze the changing pattern of the bird community after the construction of artificial wetland at Sihwah lake from may 2000 to January 2002. Total seventy seven bird species were recorded at Sihwa artificial wetland area during the survey. Number of the bird species and individuals were increased in second year than first survey year. Especially shorebirds and raptors were more increased than other groups. Long-term and continuous monitoring of bird community would be needed to clarify the reasons of increasing pattern of bird species and individuals in artificial wetlands of Sihwa lake. Until now, this area has been considered as suitable habitat for dabbling ducks than shore birds and has simple habitat environment consisting of open water surface and reed beds. Therefore, we suggest the follows for creation of diverse habitat types: 1) seasonal water-level manipulation 2) management of diverse aquatic plants and 3) creation of diverse land cover; sandy fields, gravelly fields, grasslands, etc.