Ranaviruses are a primary cause of amphibian extinctions. More consistent ranavirus-infection reports and genetic characterizations of identified viruses are urgently needed, particularly from Asian countries. The objectives of this study were to obtain the partial major capsid protein (MCP) gene sequences (506 bp) of the ranavirus responsible for infecting frogs in South Korea, as our previous research had confirmed using qPCR, and to evaluate their genetic relationships with other previously reported ranavirus sequences. Three different ranavirus MCP sequences were obtained from Pelophylax nigromaculatus and Lithobates catesbeianus. All six different types of MCP sequence from the ranavirus identified in South Korea to date belonged to the Frog virus 3 (FV3)-like virus group in the genus Ranavirus. To better understand the origin and spread of ranaviruses in South Korea, further infection reports and full genome analyses of the identified ranaviruses are needed.

Background: The Arctic permafrost stores enormous amount of carbon (C), about one third of global C stocks. However, drastically increasing temperature in the Arctic makes the stable frozen C stock vulnerable to microbial decomposition. The released carbon dioxide from permafrost can cause accelerating C feedback to the atmosphere. Soil organic matter (SOM) composition would be the basic information to project the trajectory of C under rapidly changing climate. However, not many studies on SOM characterization have been done compared to quantification of SOM stocks. Thus, the purpose of our study is to determine soil properties and molecular compositions of SOM in four different Arctic regions. We collected soils in different soil layers from 1) Cambridge Bay, Canada, 2) Council, Alaska, USA, 3) Svalbard, Norway, and 4) Zackenberg, Greenland. The basic soil properties were measured, and the molecular composition of SOM was analyzed through pyrolysis-gas chromatography/mass spectrometry (py-GC/MS). Results: The Oi layer of soil in Council, Alaska showed the lowest soil pH and the highest electrical conductivity (EC) and SOM content. All soils in each site showed increasing pH and decreasing SOC and EC values with soil depth. Since the Council site was moist acidic tundra compared to other three dry tundra sites, soil properties were distinct from the others: high SOM and EC, and low pH. Through the py-GC/MS analysis, a total of 117 pyrolysis products were detected from 32 soil samples of four different Arctic soils. The first two-axis of the PCA explained 38% of sample variation. While short- and mid-hydrocarbons were associated with mineral layers, lignins and polysaccharides were linked to organic layers of Alaska and Cambridge Bay soil. Conclusions: We conclude that the py-GC/MS results separated soil samples mainly based on the origin of SOM (plants- or microbially-derived). This molecular characteristics of SOM can play a role of controlling SOM degradation to warming. Thus, it should be further investigated how the SOM molecular characteristics have impacts on SOM dynamics through additional laboratory incubation studies and microbial decomposition measurements in the field.

Background: Climate change significantly influences the geographical distribution of plant species worldwide. Selecting indicator species allows for better-informed and more effective ecosystem management in response to climate change. The Korean Peninsula is the northernmost distribution zone of warm temperate evergreen broad-leaved (WTEB) species in Northeast Asia. Considering the ecological value of these species, we evaluated the current distribution range and future suitable habitat for 13 WTEB tree species designated as climate-sensitive biological indicator species. Results: Up-to-date and accurate WTEB species distribution maps were constructed using herbarium specimens and citizen science data from the Korea Biodiversity Observation Network. Current northern limits for several species have shifted to higher latitudes compared to previous records. For example, the northern latitude limit for Stauntonia hexaphylla is higher (37° 02' N, Deokjeokdo archipelago) than that reported previously (36° 13' N). The minimum temperature of the coldest month (Bio6) is the major factor influencing species distribution. Under future climate change scenarios, suitable habitats are predicted to expand toward higher latitudes inland and along the western coastal areas. Conclusions: Our results support the suitability of WTEB trees as significant biological indicators of species' responses to warming. The findings also suggest the need for consistent monitoring of species distribution shifts. This study provides an important baseline dataset for future monitoring and management of indicator species' responses to changing climate conditions in South Korea.

Background: Filter-feeding zooplankton has limited food resources owing to their habitat. Consequently, it is crucial for them to acquire all essential compounds, such as fatty acids (FAs) and amino acids, from confined diets. To elucidate the trophic transfer of FAs to filter feeders, the primary consumers in freshwater ecosystems, we compared the FA accumulation patterns of two species of filter-feeding zooplankton, Daphnia magna and Branchinella kugenumaensis, in a laboratory experiment. Experimental neonates and nauplii preyed on a single phytoplankton species (Selenastrum capricornutum) for three days after hatching prior to diet switching. Five replicates per feeding group in each species were fed on six different types of mixed phytoplankton diet for 10 days after diet switching. Subsequently, the consumers and diets were harvested and FAs were extracted. Results: Principal component analysis showed that the FA profiles of zooplankton were well-grouped by species and diet. Although diet affects the FA profiles of consumers, they exhibit different FA accumulation patterns. D. magna had a higher 18C-ω3 content and ω3/ω6 ratio than did B. kugenumaensis. In contrast, B. kugenumaensis had higher contents of 18:1ω7 and 20:5ω3 (eicosapentaenoic acid), 22:6ω3 (docosahexaenoic acid), and a higher ratio of ∑18C monounsaturated FAs to ∑18C-ω3 polyunsaturated FAs than did D. magna. Conclusions: This study showed that two primary consumers, D. magna and B. kugenumaensis, fed the same diet had different assimilation patterns of FAs under controlled environments. Specific FA accumulation patterns in filter feeders can provide information on the transfer process of various FAs to high-trophic organisms.

Background: We developed a habitat suitability index (HSI) model for Pedicularis hallaisanensis, a Grade II Endangered Species in South Korea. To determine the habitat variables, we conducted a literature review on P. hallaisanensis with a specific focus on the associated spatial factors, climate, topography, threats, and soil factors to derive five environmental factors that influence P. hallaisanensis habitats. The specific variables were defined based on the collected data and consultations with experts in the field, with the validity of each variable tested through field studies. Results: Mt. Seorak had a suitable habitat area of 2.48 km² for sites with a score of 1 (0.62% of total area) and 0.01 km² for sites with a score of 0.9. Mt. Bangtae had a suitable habitat area of 0.03 km² for sites with a score of 1 (0.02% of total area) and 0 km² for sites with a score of 0.9. Mt. Gaya showed 0.13 km² of suitable habitat for sites with a score of 1 (0.17% of total area) and 0 km² for sites with a score of 0.9. Lastly, Mt. Halla showed 3.12 km² of suitable habitat related to sites with a score of 1 (2.04% of total area) and 4.08 km² of sites with a score of 0.9 (2.66% of total area). Mt. Halla accounts for 73.1% of the total core habitat area. Considering the climatic, soil, and forest conditions together with standardized collection sites, our results indicate that Mt. Halla should be viewed as a core habitat of P. hallaisanensis. Conclusions: The findings in this study provide useful data for the identification of core habitat areas and potential alternative habitats to prevent the extinction of the endangered species, P. hallaisanensis. Furthermore, the developed HSI model allows for the prediction of suitable habitats based on the ecological niche of a given species to identify its unique distribution and causal factors.

Background: The Korean scarlet dwarf, Nannophya koreana Bae (Odonata: Libellulidae), is anendangered dragonfly with an increasing risk of extinction owing to rapid climate changes and human activities. To prevent extinction, the N. koreana population and their habitat should be protected. Therefore, suitable habitat evaluation is important to build the N. koreana restoration project. The habitat suitability index model (HSI) has been widely used for habitat evaluation in diverse organisms. Results: To build a suitable HSI model for N. koreana, 16 factors were examined by seven experienced researchers. A field survey for N. koreana observed sites and spatial analysis were conducted to improve the model. Five factors were finally selected by this procedure (crown density, open water surface, water depth, pioneer plant cover, and type of water source). Finally, the N. koreana HSI model was generated with the five adjusted factors based on interview, field survey, and spatial analysis. This model was validated by a current N. koreana habitat in 2021. With this model, 46 sites in Uljin-gun, Korea, were surveyed for N. koreana habitats; five sites were identified as core habitats and seven as potential core habitats. Conclusions: This model will serve as a strong foundation for the N. koreana restoration project and as a reference for future studies on N. koreana and other endangered insect populations. Further analysis and long-term data will improve the efficacy of this model and restore endangered wildlife.