The periodic occurrence of biological population is affected by several biological and environmental factors and ancient literature survey offers insight into ecological process related to the cyclicity. The periodic occurrence of a Lepidopteran species, the pine caterpillar (Dendrolimus spectabilis), was estimated based on ancient literature survey. The pine caterpillar was one of the most injurious defoliators of pine trees in northeast Asia, especially Korea during 1960s and 1970s. Outbreaks of this species have long history in Korea. Since about 900 years ago, damages of pine forest by this species and its control were recorded both in History of Corea dynasty which cover 475 years (918-1392) of the history of the Corea Dynasty and in the Annals of Joseon Dynasty (Joseon Wangjo Shillok) which cover 472 years (1392-1863) of the history of the Joseon Dynasty, respectively. At least over 20 and 30 occurrences of pine caterpillar were recorded during Corea dynasty and Joseon Dynasty, respectively. These results showed that the pine caterpillar had been one of the most severe forest pests during Corea and Joseon Dynasty. Our result showed that the ancient literature survey is useful to understand the long-term periodic occurrence of the pine caterpillar.

Metcalfa pruinosa (Hemiptera: Flatidae) is a invasive and harmful insect in South Korea. It is originated from the Nearctic region. Since M. pruinosa was first identified in South Korea in 2005, it dispersed throughout the country. In this study, we investigated the dispersal ability of M. pruinosa in the field in three different levels: 1) short distance movement, 2) flying movement, and 3) dispersal distance in large area in the two different landscape types (open canopy and forest with covered canopy). Our results showed that the movement ability of M. pruinosa was weak in walking. However, it displayed long dispersal distance that increasing dispersal distance in each year. These results can be used for modelling dispersal distance of the species.

Forest insect pests are severe disturbance factors in forest ecosystems, inducing the diverse negative impacts on the forestry economy, ecosystem service, biodiversity, and sustainable ecosystem management. Majority of forest insect pests are invasive species in many countries. To understand the occurrence patterns including population dynamics and dispersal of species, ecological modelling is popularly considered as a tool. Ecological modelling can provide information that is required for decision making through hazard ratings, the examination of potential impacts, and the prediction of dispersal patterns for forest pests. In this study, we review the modelling methods and present some case studies conducted in Korean forests.

Headwater streams provide various microhabitats, resulting in high diversity of macroinvertebrate community. In this study, we compared the differences of communities between two adjacent headwater streams (Jangjeon stream (GRJ; GRJ1-GRJ5) and Haanmi stream (GRH; GRH1-GRH3)) in Jungwang and Gariwang mountains, Gangwon-do and evaluated the effects of habitat condition to the macroinvertebrates community composition. In order to characterize the macroinvertebrate communities and extract influential environmental factors, we applied to Cluster analysis (CA), Indicator species analysis and Non-metric multidimensional scaling (NMDS). Total 33,613 individuals in 3 phyla, 5 classes, 13 orders, 51 families, and 114 taxa (genera or species) were collected. Gammarus sp. was dominant at the upper stream of GRJ, whereas Chironomidae spp. was abundant at GRH and the downstream of GRJ. The CA classified samples into six clusters (1-6) reflecting spatial and temporal variation of benthic macroinvertebrate communities. Benthic macroinvertebrate community composition was significantly different between two adjacent streams. Sweltsa sp. 1, Psilotreta kisoensis, Rhyacophila shikotsuensis and Serratella setigera were identified as representative indicator species for clusters 1, 2, 3 and 5, respectively. Similar to CA results, NMDS revealed the spatial and temporal differences of benthic macroinvertebrate communities, indicating the difference of community composition as well as microhabitat condition. Forest composition, proportion of boulders (>256 mm), and water velocity were main factors affecting the macroinvertebrate community composition.

The distribution of benthic macroinvertebrates was investigated at 1,157 sites of 7 main water systems in Korea, including 442 sites of Han River system (Namhan River, Bukhan River, Han River main stream, Anseongcheon, etc.), 305 sites of Nakdong River system (Nakdong River, Hyeongsan River, Taehwa River, etc.), 199 sites of Geum River system (Geum River, Sapgyocheon, Mangyeong River, Dongjin River, etc.) 102 sites of Seomjin River system (Seomjin River), 102 sites of Yeongsan River system (Yeongsan River, Tamjin River, etc.), and 7 sites of Jeju stream system. A total of 151 families were found in the whole survey sites, including 141 families in Han River, 122 in Nakdong River, 115 in Geum River, 106 in Seomjin River, 113 in Yeongsan River, and 50 in Jeju. Chironomidae (20.8%) was the most dominant species in Korea, followed by Hydropsychidae (17.1%), Baetidae (12.6%), Tubificidae (10.3%), Heptageniidae (8.6%), Ephemerellidae (6.3%), Asellidae (2.7%), Leptophlebiidae (2.4%), Planariidae (1.7%), and Tipulidae (1.6%). Substrates compositions consisted of large sand (22.6%), large gravel (18.4%), silt (10.5%), and boulder (8.2%). The mean stream width was 133.5 m and the mean watercourse width was 61.7 m. The mean water depth and velocity were 30.2 cm and 33.1 cm s-1, respectively. Results of cluster analysis based on distributional characteristics of benthic macroinvertebrates were divided into six groups according to the frequency of benthic macroinvertebrate taxa which appeared in the study area. Finally, altitude, current velocity and substrate composition were the most influencial factors determining the distribution patterns of macroinvertebrate communities.

Headwater streams are main sources of water, sediments, and organic materials that are transported downstream. Inthis study, we characterized the variability in benthic macroinvertebrate communities according to spatio-temporal variationresponding to the differences of environmental characteristics. We collected benthic macroinvertebrates at five samplingsites along longitudinal gradient on the Jangjeon stream in the Gariwang Mountain at three different seasons (spring, summerand autumn). We identified 93 taxa in 44 families. The dominant species was Gammarus sp. at the upper stream, whileit was Chronomidae spp. at the downstream. Changes of functional feeding guilds was clearly observed along the longitudinalgradient. Species turnover rates was higher in summer than in other seasons. The habitat condition including the landcover of their riparian zone and hydrological factors were major factors influencing on the community composition.

Ecological communities have high variability with complex interactions between biological components as well as withtheir environmental factors. To characterize the properties of communities, much works used species diversity concerningtaxonomic richness. Meanwhile, functional diversity based on biological traits are frequently used in recent communitystudies. Functional diversity is the extent of functional differences among species, driving the relationship between biodiversityand ecosystem functioning. Therefore, understanding the relationship between species diversity and functional diversityis fundamental in community ecology as well as conservation biology. Many studies presented that biological traits areefficient to achieve a predictive framework for ecosystem functioning. In this study, we present the relationship betweenspecies diversity and functional diversity.

Introduction of invasive species into a new ecosystem may have various impacts such as including environmental harm,economic harm, or impact human health. After the establishment of population in a new area, a range of its habitat isexpanded. Hazard assessment for invasive species provides fundamental information for identifying current or future hazardouscondition, and it is important for the surveillance of pest occurrence as well as the development of control strategy. Itcan be also used for determining control areas and methods. Various approaches have been used in the hazard assessmentfor forest invasive species including statistical model, aerial approaches, and machine learning models. In this study, wepresent some approaches in the hazard assessment for forest pests including pine needle gall midge and pine wilt disease.

Odonata are widely distributed in the global scale. Their distribution and abundance influenced by various environmental factors where they habit. Therefore, their distribution patterns reflect the differences of their habitat condition. In this study, we characterized the distribution patterns of Odonata in korean streams by considering various environmental condition such as geographical, landscape, hydrological, and water quality factors. Species Ischmura asiatica, Cercion calamorum, and Onychogomphus ringens displayed the highest abundance and occurrence frequency in the dataset. Among various environmental factors altitude was the most contributing factors on the distribution of Odonata species, and the species richness was higher at low land than at high land.

Oligochaetes distribute widely in freshwater ecosystem, and some species are used as bioindicators for water quality assessment because they are tolerant to organic enrichment. They are acknowledged for potential for environmental health recovery of organic polluted environment. There are a lot of studies on ecology and toxicity assessment using oligochaetes in aquatic environment. In this study, we reviewed literature on ecotoxicology of aquatic oligochaetes. We searched literature from a database ‘google scholar’ by using keywords such as aquatic, oligochaete, and toxicity. The literature were summarized according to publication years, species, test methods, and chemicals. We obtained 133 articles published from 1953 to 2015 from the database. Among them, 58 papers (43.6% of total) have been published in 1990s. Three species (Lumnbriculus variegatus, Tubifex tubifex, and Limnodrilus hoffmeisteri) have been used most frequently in the study. Different species displayed different toxicological responses to different toxic chemicals. The results on the ecotoxicological study with aquatic oligochaetes revealed the possibility of the development for early warning system using aquatic oligochaetes to monitor aquatic ecosystem disturbance.

Investigating loci compositions by conventional methods is limited in fully addressing complex gene information. We applied self-organizing map (SOM) to characterize Amplified Fragment Length Polymorphism (AFLP) of aquatic insects in six streams in Japan in responding to environmental variables. Locus band presence patterns were clustered by the trained SOM. Presence and absence data of loci were altered and cluster change through recognition was Subsequently expressed to indicate sensitivity to environmental variables. The outlier loci were determined based on the 90th percentile. Subsequently environmental responsiveness was obtained for each outlier in different species. Outlier loci were overall sensitive to pollutants and feeding material. Poly-loci like responsiveness was detected in adapting to environmental constraints. SOM training combined with recognition could be an efficient means of characterizing loci information without knowledge on population genetics a prior.

Butterflies are commonly used for environmental monitoring to assess biodiversity changes in the world. Occurrence of butterflies were monitored by a line transect method in Gwangneung forest for 10 years from 2005 to 2014. Totally, 8,484 individuals of 96 species of butterflies were identified. Among them, two species Libythea celtis (2807 individuals) and Pieris melete (1517 individuals) were the most abundant species, followed by Argynnis paphia (381 individuals) and Neptis philyroides (277 individuals). Meanwhile, Pieris melete and Libythea celtis showed high occurrence frequency with 84.6% (99 times among the 117 monitoring times) and 76.9% (90 times) respectively, followed by Argynnis paphia (42.7%) and Pieris canidia (40.2%). Species richness and abundance were varied at different years, and they were slightly decreasing in recent years. Most species showed annual variation in their abundance. Species abundance distribution model showed a log-normal distribution.

Headwater streams are the main sources of water sediment and organic material for downstream reaches and their small catchments coupled terrestrial-aquatic linkages. Because headwater streams provide valuable habitats for unique and diverse assemblages of aquatic fauna, they are also essential for sustaining the structure and function of the watersheds. Therefore, it has been recently supported that headwaters are important areas for maintaining biodiversity. In this study, we surveyed four different headwater streams in different watersheds to characterize differences of benthic macroinvertebrate assemblages among study streams. Benthic macroinvertebrates were collected seasonally with a Surber net at four different streams. In addition, hydrological and physicochemical environmental factors including temperature, discharge, width, conductivity, dissolved oxygen and pH were also measured at each sampling site. Community indices were used to differentiate spatiotemporal changes of macrointertebrate communities. Multivariate analysis were used to characterize the relationships between communities and environmental factors. Differences of their environmental condition such as meteorological factors and stream hydromorphological factors were reflected in the ordination with macroinvertebrate communities.

The fall webworm (FWW), Hyphantria cunea, defoliates most deciduous trees. After the first detection of FWW in Seoul in 1958, FWW had dispersed to the entire South Korea by 1972. Although currently the FWW density is not high, the defoliation is still reported in the nationwide. In Korea, FWW hibernates as a pupa and emerges between mid May and early June. Generally it is accepted that FWW has a bivoltine life cycle in South Korea: the first generation between mid May and early June and the second generation from late July to late August. However, recently the possibility of trivoltine populations in Korea has been discussed based on the field observations. In this study, we analyzed the field monitoring data and developed a model to predict occurrence patterns of FWW. We discuss the possibility of trivoltine populations in Korea based on the model developed.

Benthic macroinvertebrates are sedentary and have an intermediate life span ranging from months to a few years. They play a key role as consumers in the food trophic structure by linking producers, top carnivores, and decomposers in aquatic communities. Therefore, they have been widely used for ecological assessment of aquatic ecosystem health in an integrative and continuous manner. In this study, we characterized benthic macroinvertebrate communities at reference sites, which are not disturbed. Benthic macroinvertebrates were collected seasonally with a Surber net at three different streams (Pocheon, Hongcheon, and Namhae). In addition, hydrological and physicochemical environmental factors including temperature, discharge, width, conductivity, dissolved oxygen and pH were also measured at each sampling site. Spatial and temporal differences of benthic macrointertebrate communities were analyzed based on community indices, functional guilds, etc. relating to their environmental factors. Multivariate analysis were used to characterize the relationships between communities and environmental factors. Benthic macroinvertebrates were significantly different among sampling sites reflecting differences of their environmental condition such as hydromorphological factors, meteorological factors, etc.