Climate and atmospheric carbon dioxide are significant factors in ecological risk assessments, suggesting their consideration is required in predicting potential distribution of a invasive species. CLIMEX model is one of species distribution models (SDMs) and provides potential geographical distribution by focusing on climatic effect on species inhabitation. Most SDMs, such as Bioclim, Domain, GARP and MaxEnt, focus on relationship between the occurrences of the species and static environmental covariates, whereas CLIMEX model depends on limitations of species' geographical distribution and reactions to climatic variables at an appropriate temporal scale (called seasonal phenology). In this study, we described the basic concept of CLIMEX and reviewed previous applications. Also, we demonstrated the various utilization of CLIMEX differed by study purposes and methodology for analyzing the model.

Phthorimaea operculella is a pest causing serious damages in worldwide potato cultivation. As climatic factors are considered to be the most crucial on species’ distribution, we tried to compare climatic conditions between a native area of Phthorimaea operculella with cities in South Korea and other areas in Asia based on climatic similarity provided by 'Match Climates' function of CLIMEX software. Even though there is arguing regarding origin of Phthorimaea operculella, we selected Peru and Bolivia as home climate, and compared its climatic similarity to other areas in Asia with application of SRES A1B 2030 climate change scenario. Result showed that South Korea has favorable climatic condition for Phthorimaea operculella. Also, most of Asia except north China and south Russia showed the similar climate suitable for Phthorimaea operculella.

Mythimna separata (Lepidoptera: Noctuidae) is a notorious migratory pestand has caused significant damage in NortheastAsia including South Korea. For this reason, predicting occurrence time and distribution area considered to be an importantfor establishing early control plan. Because it cannot survive during the winter in South Korea and occurs seasonallydue to invasion from the southeast of China, general application of CLIMEX may not be adequate. Therefore, we appliedCLIMEX for analyzing seasonal occurrence M. separata of based on its growth index (GI) predicted in accordance withclimate. As a result, GI in southern region of South Korea began to occur at the earliest time and showed the highestvalue from the end of April to the beginning of September.

Invasive pests have posed an ecological threat as climate change has been accelerated, suggesting early prediction ofinvasive pests is required to minimize damages by them. As one of predictive tools, CLIMEX has been effectively usedin a few regions, including US, Australia, and Europe. It allows us to predict a species distribution on a local area inresponse to climatic conditions: and thus, potential distribution of invasive species, risk assessment of agricultural pests,and suitability of biological control agents have been tested by CLIMEX. In this study, we introduced how to use CLIMEXfor predicting a species distribution differed by climate change in terms of its functions, required data, and examplesof its application.

The first record of Melon thrips, Thrips palmi Karny, was in 1993 in Korea, and the species has become severe pest in agricultural industry. We used two different SDMs(Species Distribution Model) which have different approaches to analyse potential distribution of the pest species in climate change scenario, MaxEnt and CLIMEX. The MaxEnt model uses historical occurrence records with environmental variables to estimate the realized niche, and CLIMEX model simulates the fundamental niche of the object based on the seasonal phenology. In MaxEnt simulation, we reduced the number of variables to avoid multi-collinearity problem until we had no pairs with an absolute Pearson correlation coefficient higher than 0.8. BIO1(Annual Mean Temperature), BIO2(Mean diurnal range), BIO3(Isothermality), BIO4(Temperature seasonality) were finally selected as predictor, and we used 10 fold cross validation option to replicate. The averaged results were used to index analysis. The CLIMEX results, The Ecoclimate Index(EI), were also normalized in 0 to 1 scale to analysis. Under RCP 8.5 climate change scenario, in 2070s, the distribution of Thrips palmi was predicted to expand their territory overall agricultural area in Korea.

The establishment of insect population in certain region is affected by three major characteristics, the host spectrum, the phenological plasticity and the overwintering strategy. The geographical distribution of insect population is directly affected by their successful establishment in local environment, thus, in case of development of potential geographical distribution models, three major characteristics should be considered carefully. In this study, we developed geographical distribution model using CLIMEX system with well-known insect species, Carposina sasakii. Its geographical distribution is limited to northeast Asia including Korea, Japan, China and the Soviet Far East. C. sasakii overwinters as a full-grown larva within spherical and compactly woven larval-cocoons in the soil. We calculated Diapause Index (DI) then incorporated DI into CLIMEX system to simulate Ecoclimatic Index (EI), which stands for ability of establishment in a certain area for further studies of geographical distribution of insect populations which have overwintering strategy in their life history.

Thrips palmi Karny was introduced and first recorded in 1993 in Korea. This species has become a serious pest of vegetable and ornamental crops. CLIMEX simulation was applied to T. palmi to predict the potential geographic distribution in Korea under the Representative Concentration Pathway (RCP) 8.5 climate change scenario. In the CLIMEX simulation, ecoclimatic index (EI) was calculated, and compared in each simulated year and each simulated location. The map comparisons showed a good agreement between simulated and present distributions of T. palmi, indicating that the CLIMEX model was well explained and appropriate for prediction of future distributions of this species in Korea. In near future, until a year of 2020, all the western and eastern parts of Korea showed favorable to marginal suitability for T. palmi populations in fields. After the year of 2040, the potential distributions are shifted from no persistent to favorable for establishment and persistence from coastal to interior of the Korean peninsula except a north-eastern interior region which is the northernmost part of high mountains (Baekdu-Daegan) area in South Korea. Based on simulation results, T. palmi would overcome its weather restriction in near future under a severe climate change scenario, thus, pest management measures and strategies should be re-constructed in Korea, with further studies including interspecific competition and understanding ecosystem change due to climate change.

Earth’s average temperature has risen by 0.78°C over the past century, and is projected to rise another 1.1 to 6.4°C over the next hundred years based on recent announced RCP8.5 climate change scenario. Small changes in the average temperature of the planet can translate to large and potentially dangerous shifts in biosphere. Based on climate change scenario, local distribution of well-known species should be changed in near future. Models, if applied appropriately, give useful and rapid predictions of the potential distribution of the target species. CLIMEX is one of modeling systems that may provide insights into the climatic factors that limit the geographical distribution of a species in different parts. Climatic parameters and the climate matching function of CLIMEX enable the risks of an exotic species as well as well-known species to be assessed by directly comparing the climatic condition of a given location with any number of other locations without knowing the full distribution of a species. However, CLIMEX supports only three locations in Korea (Seoul, Pusan and Kangnung province). We generated detail weather database of Korea for CLIMEX, and simulated using the data of American serpentine leafminer, Liriomyza trifolii (Burgess), a key pest and well-known species in Korea for application of future risk assessment under possible climate change condition in Korea.

국제화와 농산물의 빈번한 수출입으로 인해 국내에 보고되지 않았던 외래해충 의 침입이 점차 늘어 최근까지 기록된 외래해충은 블루베리혹파리 등 총 42종에 달 한다. 우발적으로 유입된 검역 해충들의 국내 정착 가능성 여부 및 확산의 예측은 이들 해충들의 박멸 및 발생 지역 확산 방지를 위하여 필수적인 과정이다. 따라서 본 연구는 오이총채벌레(Thrips palmi)등 2종의 기 침입 해충과 침입 가능성이 있 는 나방 1종(Light brown apple moth, Epiphyas postvittana) 등 2종의 정착 가능성 분석을 위해 상용 프로그램인 CLIMEX® (version 3.0) (Sutherst et al., 2007)와 문 헌에 수록된 매개변수 값을 이용하였다. 정착 가능성 분석은 68개 시군을 대상으로 평년(30년) 기상자료와 기후변화 모델 1종을 사용하였다. 분석 결과 EI (Ecoclimatic index)값이 10 이상으로 보통의 정착가능성 있는 지역의 수가 오이총 채벌레는 제주도 서귀포 등 3개 지역, 미국선녀벌레 (Metcalfa pruinosa)는 대구 등 47개 지역, Light brown apple moth(LBAM)는 제주도 고산 등 2개 지역이었으나 지중해과실파리(Ceratitis capitata)는 한 지역도 없었다. 그러나 사계절 최저, 최고 온도가 3℃ 상승하고 강우량이 겨울에는 20% 감소하고 여름에는 20% 증가하는 기후 변화에 따른 결과는 오이총채벌레, LBAM, 지중해과실파리 3종 모두 국내 남 부 해안 지역까지 정착 가능성이 있는 것으로 분석되었다.

Light brown apple moth, Epiphyas postvittana, is a significant horticultural pest native to Australia, and currently with a limited global distribution. However it can tolerate very heterogeneous climatic and vegetation conditions and has recently invaded California with considerable consequences for US international and domestic trade. By comparing the climatic conditions of its native (Australia) and long-established (New Zealand) ranges to the rest of the world using CLIMEX, it was suggested that E. postvittana has potential to establish mainly in countries in Central and South America, southern Africa, west Europe and South-east Asia. However, the predicted global distribution of E. postvittana using a new multiple-species-distribution model system suggested that there are additional climatically suitable areas around the world where this species could potentially survive and establish. Our study provides basic but important information for further assessment of the establishment capacity of this species in new habitats, wihch will provide the knowledge required to make science-based decisions in biosecurity.