• Korean Journal of Environment and Ecology
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• v.38 no.1
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• pp.67-78
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• 2024

The term ecosystem services refers to natural ecosystems' benefits to humans. Various models have been developed and applied to quantify ecosystem services. Habitat quality assessment is a widely used leading InVEST ecosystem service model. In Korea, habitat quality assessment is conducted for national parks. For habitat quality assessment, the initial value of habitat quality must be used to assess the sensitivity to threats, which varies depending on the country and application field. Therefore, an expert survey (AHP) was conducted based on previous habitat quality assessments in national parks to adjust the sensitivity, the initial value for the habit quality assessment. As a result of the AHP, 18 items were adjusted, including 10 items, such as natural grassland and unarranged fields, upward and 8 items, such as rivers and ponds, downward. Based on the adjusted sensitivity results, the habitat quality of Bukhansan National Park and Gyeryongsan National Park (urban type), Gyeongju National Park (historic type), Hallyeohaesang National Park (ocean type), and Jirisan National Park and Seoraksan National Park (mountain type) were adjusted. The results of the analysis showed that the habitat quality of urban dry areas and water bodies distributed in the national parks was reflected in the habitat quality assessment. In the future, it will be possible to evaluate the habitat quality of natural parks using this standard.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.3
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• pp.1-15
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• 2016

The study of ecosystem service assessment has been actively researched and developed from Millennium Ecosystem Assessment(MA) and The Economics of Ecosystems and Biodiversity(TEEB). However, current assessments are limited to monetary assessments of ecosystem function and do not account for the effects of environmental factors and socioeconomic status. This study proposes methods to evaluate ecosystem service based on environmental and socioeconomic factors. The study assesses water yield function through the water yield model in InVEST Tool, and evaluates the overall ecosystem service of water yield as reflected by the amount of precipitation and population of the area. Results show that a difference exists between spatial distributions of the ecosystem function of water yield derived from natural conditions such as land cover and soil, and the spatial distribution of the ecosystem service that accounts for climate and socioeconomic factors. The value of ecosystem service increases for an area of higher population and lower precipitation with similar water yield. Thus, the ecosystem service of water yield should be evaluated not only by the water yield function, but also by climate and socioeconomic factors. The evaluation process described for this study should also be applicable to the evaluation of ecological services in other sectors.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.238-244
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• 2012

Toxic effects of heavy metal (Pb, Cr, As) were examined by the hatching rates of fertilized eggs in the oliver flounder, Paralichthys olivaceus. Eggs were exposed to Pb, Cr, As (0, 10, 100, 500, 1,000, 2,500, 5,000 ppb) and then normal hatching rates were investigated after 48 h. The normal hatching rates in the control condition (not including heavy metal) were greater than 80%, but suddenly decreased with increasing of heavy metal concentrations. Pb, Cr and As reduced the normal hatching rates in concentration-dependent way and a significant reduction occurred at concentration grater than 100, 100, 500 ppb, respectively. The ranking of heavy metal toxicity was Cr>As>Pb, with $EC_{50}$ values of 415, 518 and 1,029 ppb, respectively. The no-observed-effect-concentration (NOEC) and lowest-observed-effect-concentration (LOEC) show each 100 bbp and 500 ppb of normal hatching rates in exposed to Pb and As. The NOEC and LOEC of normal hatching rates in Cr were 10 ppb and 100 ppb, respectively. From these results, the normal hatching rates of P. olivaceus have toxic effect at greater than the 100 ppb concentrations in Pb, As and the 10 ppb concentrations in Cr in natural ecosystems. These results suggest that biological assay using the normal hatching rates of P. olivaceus are very useful test method for the toxicity assessment of a toxic substance as heavy metal in marine ecosystems.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.16-27
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• 2019

Alteration in the flow regime of rivers are caused by natural climate change and the changes in anthropogenic hydrological environment due to dam construction. These changes in flow regime cause serious changes not only in the fresh water ecosystems of the rivers but also in the physical structures and fish habitats of the streams. In this study, the alteration in the hydrological characteristics of the Gam river basin due to Buhang dam construction and the changes in ecological health condition, water quality, and river cross-section were analyzed. As a result of analysis by indicators of hydrologic alteration (IHA) to quantitatively change the flow regime of Gam river, HA (Hydrologic Alteration) is more than ±1 and various changes have occurred in the river ecosystem after Buhang dam construction. In addition, ecological health condition and water quality showed different response for each element, and in the case of riverbeds and channel cross-sections, the degradation of channel bed was obviously monitored after dam construction. The results of this study are expected to be used as an efficient method for evaluating changes in stream ecosystems caused by stream regime changes.

• Ocean and Polar Research
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• v.39 no.1
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• pp.13-21
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• 2017

Temporal changes in the number of zooplankton species are important information for understanding basic characteristics and species diversity in marine ecosystems. The aim of the present study was to estimate the optimal monitoring frequency (OMF) to guarantee and predict the minimum number of species occurrences for studies concerning marine ecosystems. The OMF is estimated using the temporal number of zooplankton species through bi-weekly monitoring of zooplankton species data according to operational taxonomic units in the Tongyoung coastal sea. The optimal model comprises two terms, a constant (optimal mean) and a cosine function with a one-year period. The confidence interval (CI) range of the model with monitoring frequency was estimated using a bootstrap method. The CI range was used as a reference to estimate the optimal monitoring frequency. In general, the minimum monitoring frequency (numbers per year) directly depends on the target (acceptable) estimation error. When the acceptable error (range of the CI) increases, the monitoring frequency decreases because the large acceptable error signals a rough estimation. If the acceptable error (unit: number value) of the number of the zooplankton species is set to 3, the minimum monitoring frequency (times per year) is 24. The residual distribution of the model followed a normal distribution. This model can be applied for the estimation of the minimal monitoring frequency that satisfies the target error bounds, as this model provides an estimation of the error of the zooplankton species numbers with monitoring frequencies.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.72-81
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• 2020

Blooms of the small centric diatom Stephanodiscus is quite occasional in winter season in temperate freshwater ecosystems. Often, it leads to degradation of water quality and affects quality of supplied drinking water. In previous studies, naphthoquinone (NQ) compounds have been shown to be effective and selective for controlling winter bloom species Stephanodiscus hantzschii. We conducted a 5 ton scale mesocosm experiment to investigate the effects of NQ on native Stephanodiscus sp. collected from Nakdonggang River in water. After treatment with NQ 4-6 compound (0.2 μM), the cell density of Stephanodiscus sp. was rapidly reduced from 5 × 10³ cells mL^-1 to 0.2 × 10³ cells mL^-1 for 10 days. Additionally, NQ 4-6 compound did not affect physicochemical factors (water temperature, dissolved oxygen, pH, conductivity, nutrients) and biological factors (bacteria, heterotrophic nanoflagellates, zooplankton). Therefore, these findings suggest that the NQ 4-6 compound has potential as an alternative algicidal substances to effectively mitigate natural Stephanodiscus sp. blooms, and the application of NQ 4-6 compound will restore the healthy aquatic ecosystems.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.136-142
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• 2012

Acute toxicity test of heavy metal (Cd, Cu, Zn) were examined using the hatching rates of fertilized eggs in the oliver flounder, Paralichthys olivaceus. Eggs were exposed to Cd, Cu, Zn (0, 10, 100, 500, 1000, 2500, 5000 ppb) and then normal hatching rates were investigated after 48 h. The normal hatching rates in the control condition (not including Cd, Cu and Zn) were greater than 80%, but suddenly decreased with increasing of heavy metal concentrations. Cd, Cu and Zn reduced the normal hatching rates in concentration-dependent way and a significant reduction occurred at concentration grater than 1000, 100, 100 ppb, respectively. The ranking of heavy metal toxicity was Zn>Cu>Cd, with $EC_{50}$ values of 584, 1015 and 1282 ppb, respectively. The no-observed-effect-concentration (NOEC) and the lowest-observed-effect-concentration (LOEC) showed each 100 and 500 ppb of normal hatching rates in exposed to Cu and Zn. The NOEC and LOEC of normal hatching rates in Cd were 500 ppb and 1000 ppb, respectively. From these results, the normal hatching rates of P. olivaceus have toxic effect at greater than the 100 ppb concentrations in Cu, Zn and the 500 ppb concentrations in Cd in natural ecosystems. These results suggest that biological assay using the normal hatching rates of P. olivaceus are very useful test method for the acute toxicity assessment of a toxic substance as heavy metal in marine ecosystems.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.193-200
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• 2016

Toxicity assessment of heavy metals (As, Cr and Pb) has been investigated by using the rate of survival and population growth(r) of marine rotifer, Brachionus plicatilis. The survival rate was determined after 24 hours of exposure to As, Cr and Pb. As and Cr reduced survival rate in dose-dependent manner and a significant reduction were occurred at concentration of greater than 30 and $150mg\;L^{-1}$, but Pb had no effect on survival rate. The r was determined after 72 hours of exposure to As, Cr and Pb. As, Cr and Pb reduced r in dose-dependent manner and a significant reduction were occurred at concentration of greater than 5, 25 and $50mg\;L^{-1}$. The toxicity of heavy metals were ranked As>Cr>Pb, with $EC_{50}$ values of 12.98, 82.34 and $110.14mg\;L^{-1}$, respectively. The no-observed-effect-concentration (NOEC) of r in As, Cr and Pb exposure were 1, 12.5 and $50mg\;L^{-1}$, respectively. The lowest-observed-effect-concentration (LOEC) of r in As, Cr and Pb exposure were 5, 25, and $50mg\;L^{-1}$, respectively. From the results, the concentration of As, Cr and Pb (greater than 5, 25 and $50mg\;L^{-1}$, respectively) have toxic effect on the r of B. plicatilis in natural ecosystems. These results (including NOEC and $EC_{50}$) might be useful for the mixing toxicity assessment and toxic guide line of heavy metals in marine ecosystems.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.348-356
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• 2016

Carbon dioxide ($CO_2$) gases concentration in atmosphere has been growing since preindustrial times. By sequestering a large amount of atmospheric carbon (C), terrestrial ecosystems are thought to offer a mitigation strategy for reducing global warming. Woody agro-ecosystems such as fruit tree are among the least quantified and most uncertain elements in the terrestrial carbon cycle. $CO_2$ and energy fluxes were measured by the eddy covariance method on a 15-year old apple orchard of South Korea in 2006. Environmental parameters (net radiation, precipitation, etc.) were measured along with fluxes. The results showed that during late June, the ability to sequestrate C was significant at an apple orchard ecosystem and it reached on the peak of $-6.5g\;C\;m^{-2}\;d^{-1}$. We found that in the apple orchard, the daily average of net ecosystem exchange of $CO_2$ (NEE) and cumulative NEE on a yearly basis were $-1.1g\;C\;m^{-2}$ and $-396.9g\;C\;m^{-2}$, respectively. These results reveal that there is high carbon sequestration in the apple orchard of South Korea, which is the same magnitude with repect to that of a natural forested ecosystem of the same biome rank (temperate-humid deciduous forest).

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.573-580
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• 2017

The oxicity assesment of Phenanthrene (PHE) has been investigated by using the rate (r) of survival and population growth in rotifer Brachionus plicatilis. The survival rate was determined after 24 h of exposure to PHE. The survival rate of PHE had no effect at a maximum of $300mg\;L^{-1}$. The r was determined after 72 h of exposure to PHE. It was observed that r in the controls (absence PHE) was greater than 0.5, but that it suddenly decreased with an increased concentration of PHE. PHE reduced r in a dose-dependent manner and a significant reduction occurred at a concentration of greater than $37.5mg\;L^{-1}$. The $EC_{50}$ value of r in PHE exposure was $63.7mg\;L^{-1}$. The no-observed-effect-concentration (NOEC) of r in PHE exposure was $18.8mg\;L^{-1}$. The lowest-observed-effect-concentration (LOEC) of r in the PHE exposure was $37.5mg\;L^{-1}$. From the results, the concentration of PHE (greater than $37.5mg\;L^{-1}$) has a toxic effect on the r of B. plicatilis in natural ecosystems. These results(including NOEC, LOEC and $EC_{50}$) might be useful for the Polycyclic aromatic hydrocarbons(PAHs) toxicity assessment in marine ecosystems.