Conserving terrestrial linkages that connect natural landscapes of the Korean Peninsula.

Human-induced land degradation fragments natural ecosystems, hinders ecological processes, and threatens biodiversity. Maintaining or restoring ecological flows across landscapes through landscape linkages may provide a solution. Here, we identify a peninsula-wide ecological connectivity network for the Korean Peninsula using two linkage mapping models. We found three major north-south axes of connectivity traversing the Demilitarized Zone (DMZ), which emerged as an important east-west linkage. Only 7% of the highest-ranked connections are currently secured by protected areas. We found 120 linkages in North and South Korea that are intersected by road networks consisting of motorways and trunk roads under both models. These locations should be the focus of immediate attention for conservation planners, as well as 274 and 1130 additional road-impacted linkages under one model or the other. The results can be used for policy support, and potentially as a basis for the two countries to engage in discussions about ecosystem health and climate change adaptation. The approach presented here can also be efficiently used to assess and map natural landscape linkages.

Spatial and temporal patterns of microclimates at an urban forest edge and their management implications.

Fragmented forests generate a variety of forest edges, leading to microclimates in the edge zones that differ from those in the forest interior. Understanding microclimatic variation is an important consideration for managers because it helps when making decisions about how to restrict the extent of edge effects. Thus, our study attempted to characterize the changing microclimate features at an urban forest edge located on Mt. Gwanak, Seoul, South Korea. We examined edge effects on air temperature, relative humidity, soil temperature, soil moisture, and photosynthetically active radiation (PAR) during the hottest three consecutive days in August 2016. Results showed that each variable responded differently to the edge effects. This urban forest edge had an effect on temporal changes at a diurnal scale in all microclimate variables, except soil moisture. In addition, all variables except relative humidity were significantly influenced by the edge effect up to 15 m inward from the forest boundary. The relative humidity fluctuated the most and showed the deepest extent of the edge effect. Moreover, the edge widths calculated from the relative humidity and air temperature both peaked in the late afternoon (16:00 h). Our findings provide a reference for forest managers in designing urban forest zones and will contribute to the conservation of fragmented forests in urban areas.

Identification of Risk Areas for Gloydius Snakebites in South Korea.

Snakebites can pose a significant threat to human health as the destruction of natural habitats and increased human intrusion into ecosystems result in more frequent encounters with snakes. Mitigation measures for snakebites are particularly crucial for hiking trails where transportation of snakebite victims to medical facilities is challenging due to limited emergency resources and difficult access. This study employed a random forest-based species distribution model approach to investigate the potential habitats of Gloydius spp., specifically Gloydius saxatilis, Gloydius brevicaudus, and Gloydius ussuriensis, in South Korea and to assess the snakebite risk in national parks. Potential habitats of Gloydius spp. were identified and visualized by overlaying binary maps derived from species distribution models (SDMs) of each Gloydius spp. that corresponded to high-risk snakebite areas. In addition, hiking trails with high snakebite risk in the national parks were identified after demonstrating the statistical correlation between the potential habitat distribution of Gloydius spp. and the actual snakebite incidents in major regions of South Korea. The primary environmental variables determining Gloydius spp. habitat were the topographic position index, slope, and the annual average of the maximum and minimum temperatures. The potential habitat of G. saxatilis generally appeared in high-altitude mountainous areas, mostly in the eastern part of the study area. Favorable habitats for G. brevicaudus and G. ussuriensis were predominantly located in mountainous areas throughout the study area, with the exception of some high-altitude mountainous terrain in the east. The number of snakebite incidents per 10,000 people was significantly correlated with the area ratio of Gloydius spp. potential habitat (Spearman's rho = 0.638, p < 0.01). The proportion of snakebite risk areas among national parks in South Korea ranged from 18% to 57%. This study can support practical solutions to prevent injuries and fatalities among hikers due to snakebites by identifying areas with a high risk of snakebite accidents at the hiking-trail level.

Simulating Hunting Effects on the Wild Boar Population and African Swine Fever Expansion Using Agent-Based Modeling.

African swine fever (ASF) is a viral hemorrhagic fever fatal to animals of the Suidae family. It has spread from Africa to Europe and Asia, causing significant damage to wildlife and domesticated pig production. Since the first confirmed case in South Korea in September 2019, the number of infected wild boars has continued to increase, despite quarantine fences and hunting operations. Hence, new strategies are needed for the effective control of ASF. We developed an agent-based model (ABM) to estimate the ASF expansion area and the efficacy of infection control strategies. In addition, we simulated the agents' (wild boars) behavior and daily movement range based on their ecological and behavioral characteristics, by applying annual hunting scenarios from past three years (2019.09-2022.08). The results of the simulation based on the annual changes in the number of infected agents and the ASF expansion area showed that the higher the hunting intensity, the smaller the expansion area (24,987 km2 at 0% vs. 3533 km2 at 70%); a hunting intensity exceeding 70% minimally affected the expansion area. A complete removal of agents during the simulation period was shown to be possible. In conclusion, an annual hunting intensity of 70% should be maintained to effectively control ASF.

Habitat suitability and connectivity modeling predict genetic population structure and priority control areas for invasive nutria (Myocastor coypus) in a temperate river basin.

The nutria (Myocastor coypus), also known as the coypu, is a semi-aquatic, invasive rodent native to South America that causes damage to natural riverine and wetland habitats in many parts of the world, including South Korea. Understanding habitat use, connectivity, and gene flow of nutria populations is critical for the sound management of local and regional ecosystems. Here, we assessed habitat suitability and connectivity in relation to the genetic structure of nutria populations in the Nakdong River Basin of South Korea. A total of 321 nutria occurrence sites and seven environmental variables were used to perform ensemble habitat suitability modeling using five species distribution models (SDMs), including boosted regression trees, maximum entropy model, random forest, generalized linear model, and multivariate adaptive regression splines. Using graph and circuit theory approaches, we assessed the population gene flow and current flow betweenness centrality (CFBC) of suitable habitats derived from the ensemble SDM. All SDMs performed well with a range of test AUC values from 0.962 to 0.970 (mean = 0.966) with true skill statistic values over 0.8. The minimum temperature of the coldest month, mean temperature of the warmest quarter, precipitation of the driest quarter, and distance from water bodies were important predictors in nutria habitat modeling. Nutria population gene flow was significantly correlated with the least-cost path distance on a cost resistance surface based on ensemble habitat suitability modeling and roads (Mantel's r = 0.60, p < 0.05). Finally, the CFBC positively correlated with the genetic diversity of nutria populations was used to identify priority control areas. Habitat suitability and connectivity modeling not only revealed environmental conditions and areas that support the survival and spread of nutrias, but also improved our understanding of the animals' genetic population structure, thereby indicating priority areas to target for eradication.

A spatial approach to climate-resilient infrastructure in coastal social-ecological systems: The case of dumbeong in Goseong County, South Korea.

Sustainable landscape planning and management of coastal habitats has become an integral part of the global agenda due to anthroprogenic pressures and climate change-induced events. As an example of human-engineered infrastructure that enhances the sustainability and resilience of coastal social-ecological systems (SES), we have presented the dumbeong system, a farmer-engineered and managed irrigation system based on Korean traditional ecological knowledge. We analyzed the spatial relationship of dumbeongs with coastal landscape attributes and droughts in Goseong County in South Korea. We used generalized linear models (GLMs) to examine the effects of land cover and recent (2001-2010) standardized precipitation index (SPI) on the abundance of dumbeongs. Then, we projected near future (2020-2050) changes in the SPI-based drought risk for the dumbeong system using representative concentration pathway (RCP) climate scenarios. We found that forest and marine water areas have positive relations with dumbeong abundance, whereas SPI has a negative relation, indicating that the dumbeongs are more abundant in areas close to sea water and forests, and with higher incidences of drought. Derived climate change scenarios show that the study region will experience higher incidence of drought. Our findings provide empirical evidence for the dumbeong system as an effective community designed and driven adaptive response to local hydrological processes and climatic conditions, and as climate-resilient infrastructure that strengthens sustainability and resilience of coastal SES. Based on our findings, we provide recommendations for sustainable landscape management and optimal use of the dumbeong system in coastal regions.