Selection of climate variables in ant species distribution models: case study in South Korea.

The selection of explanatory variables is important in modeling prediction of changes in species distribution in response to climate change. In this study, we evaluated the importance of variable selection in species distribution models. We compared two different types of models for predicting the distribution of ant species: temperature-only and both temperature and precipitation. Ants were collected at 343 forest sites across South Korea from 2006 through 2009. We used a generalized additive model (GAM) to predict the future distribution of 16 species that showed significant responses to changes in climatic factors (temperature and/or precipitation). Four types of GAMs were constructed: temperature, temperature with interaction of precipitation, temperature and precipitation without interaction, and temperature and precipitation with interaction. Most species displayed similar results between the temperatureonly and the temperature and precipitation models. The results for predicted changes in species richness were different from the temperature-only model. This indicates higher uncertainty in the prediction of species richness, which is obtained by combining the prediction results of distribution change for each species, than in the prediction of distribution change. The turnover rate of the ant assemblages was predicted to increase with decreases in temperature and increases in elevation, which was consistent with other studies. Finally, our results showed that the prediction of the distribution or diversity of organisms responding to climate change is uncertain because of the high variability of the model outputs induced by the variables used in the models.

Acremonium (Sarocladium) periprosthetic joint infection: case report, literature review, and proposed antifungal regimen.

BACKGROUND: Fungal periprosthetic joint infections are rare. Acremonium osteoarticular infections are scarcely reported. Variable susceptibility to antifungal agents have been reported and optimal pharmacotherapy has yet to be established. Here we illustrate an Acremonium osteoarticular infection involving a prosthetic joint and present an antifungal regimen that had led to treatment success. CASE PRESENTATION: A 60-year-old female with a body mass index (BMI) of 40 had left total knee arthroplasty done in 2012 with a cementless implant for knee osteoarthritis. In 2019, the patient had asymptomatic, progressive osteolysis with fracture and migration of the femoral component warranting replacement. Eleven months later, the patient developed significant pain, redness, and swelling in the left leg and knee concerning for periprosthetic joint infection that failed outpatient antibiotic treatment. Further investigation revealed infection by Acremonium species. A revision of the joint was successfully completed, and the patient was placed on voriconazole for one year. Subsequent cultures did not yield any fungal growth. CONCLUSION: While an optimal antifungal regimen for periprosthetic joint infections has not been well established, voriconazole is a relatively safe and effective agent that can be used as a long-term therapy. With variable susceptibility testing in reported isolates, individualized antifungal susceptibility should be used to guide therapy for Acremonium infections.

High competition between ant species at intermediate temperatures.

Living organisms have been moving rapidly toward their favorable thermal regions as climate warms. Their competitive interactions will change significantly as a result of changes in distribution, abundance, and species composition. This study examines the relationship of competition intensity (frequency of competitive interactions) with temperature and the influence of competition on the occurrence of ant species. Competition between ants was surveyed at six different temperature sites using baits and the abundance of ants was surveyed using pitfall traps. The intensity of interspecific competition (abundance-corrected bait species displacement) was high at intermediate temperature sites (unimodal). Ant species are hierarchically organized in behavioral dominance. Two low-temperature ant species had decreased in the rank of behavioral dominance at warmer temperature sites because of the abundance of dominant intermediate temperature ant species. Ant species co-occurred randomly at the local scale. However, they were segregated at regional scale because of environmental filtering (temperature). Ant competition did not influence the occurrence of ant species at local or regional scale. These results suggest that the influence of changes in interspecific competition because of climate warming might not be great for ants in temperate regions.

Potential impacts of global warming on the diversity and distribution of stream insects in South Korea.

Globally, the East Asian monsoon region is one of the richest environments in terms of biodiversity. The region is undergoing rapid human development, yet its river ecosystems have not been well studied. Global warming represents a major challenge to the survival of species in this region and makes it necessary to assess and reduce the potential consequences of warming on species of conservation concern. We projected the effects of global warming on stream insect (Ephemeroptera, Odonata, Plecoptera, and Trichoptera [EOPT]) diversity and predicted the changes of geographical ranges for 121 species throughout South Korea. Plecoptera was the most sensitive (decrease of 71.4% in number of species from the 2000s through the 2080s) order, whereas Odonata benefited (increase of 66.7% in number of species from the 2000s through the 2080s) from the effects of global warming. The impact of global warming on stream insects was predicted to be minimal prior to the 2060s; however, by the 2080s, species extirpation of up to 20% in the highland areas and 2% in the lowland areas were predicted. The projected responses of stream insects under global warming indicated that species occupying specific habitats could undergo major reductions in habitat. Nevertheless, habitat of 33% of EOPT (including two-thirds of Odonata and one-third of Ephemeroptera, Plecoptera, and Trichoptera) was predicted to increase due to global warming. The community compositions predicted by generalized additive models varied over this century, and a large difference in community structure in the highland areas was predicted between the 2000s and the 2080s. However, stream insect communities, especially Odonata, Plecoptera, and Trichoptera, were predicted to become more homogenous under global warming.

Ant Mortality with Food Competition in Forests along a Temperature Gradient.

The authors elucidated the relationship between temperature and mortality due to food competition in ant communities in forests. A field experiment was conducted using four bait types at six different oak forest sites with different mean annual temperatures in South Korea. The mortality rate due to food competition showed a hump-shaped trend, with temperature distribution being higher at study sites with intermediate temperatures and a linear trend increasing or decreasing with temperature along the temperature gradient. In most species, the mortality rate due to interspecific competition was higher than that due to intraspecific competition, but the dominant species, which were less affected by other species, had a higher mortality rate due to intraspecific competition. In subordinate species that are highly affected by other species, the mortality rate due to intraspecific competition increased as the mortality rate due to interspecific competition decreased. The results indicated that mortality due to inter- or intraspecific competition for food was associated by temperature, density of other species, and species characteristics (body size, dominance, feeding strategy, and aggressiveness). Given the relationship between temperature and mortality due to food competition, the authors expect that changes in competition due to climate warming will affect the fitness of ant species.

Predicting the Global Distribution of Solenopsis geminata (Hymenoptera: Formicidae) under Climate Change Using the MaxEnt Model.

The tropical fire ant Solenopsis geminata (Hymenoptera: Formicidae) is a serious invasive species that causes a decline in agricultural production, damages infrastructure, and harms human health. This study was aimed to develop a model using the maximum entropy (MaxEnt) algorithm to predict the current and future distribution of S. geminata on a global scale for effective monitoring and management. In total, 669 occurrence sites of S. geminata and six bioclimatic variables of current and future climate change scenarios for 2050 and 2100 were used for the modeling. The annual mean temperature, annual precipitation, and precipitation in the driest quarter were the key influential factors for determining the distribution of S. geminata. Although the potential global distribution area of S. geminata is predicted to decrease slightly under global warming, the distribution of favorable habitats is predicted to expand to high latitudes under climate scenarios. In addition, some countries in America and East Asia, such as Brazil, China, South Korea, the USA, and Uruguay, are predicted to be threatened by S. geminata invasion under future climate change. These findings can facilitate the proactive management of S. geminata through monitoring, surveillance, and quarantine measures.

Association between host wing morphology polymorphism and Wolbachia infection in Vollenhovia emeryi (Hymenoptera: Myrmicinae).

Many eusocial insects, including ants, show complex colony structures, distributions, and reproductive strategies. In the ant Vollenhovia emeryi Wheeler (Hymenoptera: Myrmicinae), queens and males are produced clonally, while sterile workers arise sexually, unlike other ant species and Hymenopteran insects in general. Furthermore, there is a wing length polymorphism in the queen caste. Despite its evolutionary remarkable traits, little is known about the population structure of this ant species, which may provide insight into its unique reproductive mode and polymorphic traits. We performed in-depth analyses of ant populations from Korea, Japan, and North America using three mitochondrial genes (COI, COII, and Cytb). The long-winged (L) morph is predominant in Korean populations, and the short-winged (S) morph is very rare. Interestingly, all L morphs were infected with Wolbachia, while all Korean S morphs lacked Wolbachia, demonstrating a association between a symbiont and a phenotypic trait. A phylogenetic analysis revealed that the S morph is derived from the L morph. We propose that the S morph is associated with potential resistance to Wolbachia infection and that Wolbachia infection does not influence clonal reproduction (as is the case in other ant species).

Abundance and Distribution of Korean Flower Flies (Diptera: Syrphidae): Dominant Influence of Latitude on Regional Distribution.

Studies on abundance and distribution at different scales are rare. We examined whether the abundance of flower flies at a site in South Korea was related to the national occupancy and global distribution (distributional extent or range size) and whether the national occupancy was related to global distribution. In global distribution, the influence of two dimensions (latitude and longitude) was analyzed separately. Flower flies were collected by malaise and pitfall traps at a forest gap in South Korea. Data regarding national occupancy and global distribution were obtained from a Korean Flower Fly Atlas. We collected 46 species from the field survey and obtained a list of 119 species from the Korean Flower Fly Atlas. Our results showed that abundance at a site was positively correlated with national occupancy, but not global distribution, and the national occupancy was positively correlated with global distribution, mainly by the latitudinal range size. Finally, our results indicated that the regional distribution of flower flies was influenced by its one-dimensional global distribution.

Modelling Vulnerability and Range Shifts in Ant Communities Responding to Future Global Warming in Temperate Forests.

Global warming is likely leading to species' distributional shifts, resulting in changes in local community compositions and diversity patterns. In this study, we applied species distribution models to evaluate the potential impacts of temperature increase on ant communities in Korean temperate forests, by testing hypotheses that 1) the risk of extinction of forest ant species would increase over time, and 2) the changes in species distribution ranges could drive upward movements of ant communities and further alter patterns of species richness. We sampled ant communities at 335 evenly distributed sites across South Korea and modelled the future distribution range for each species using generalized additive models. To account for spatial autocorrelation, autocovariate regressions were conducted prior to generalized additive models. Among 29 common ant species, 12 species were estimated to shrink their suitable geographic areas, whereas five species would benefit from future global warming. Species richness was highest at low altitudes in the current period, and it was projected to be highest at the mid-altitudes in the 2080s, resulting in an upward movement of 4.9 m yr-1. This altered the altitudinal pattern of species richness from a monotonic-decrease curve (common in temperate regions) to a bell-shaped curve (common in tropical regions). Overall, ant communities in temperate forests are vulnerable to the on-going global warming and their altitudinal movements are similar to other faunal communities.

Diversity and density of butterfly communities in urban green areas: an analytical approach using GIS.

BACKGROUND: Urbanization is one of the leading causes of habitat loss, habitat degradation, and fragmentation. Urban development negatively affects biodiversity. We clarified changes in butterfly communities due to urbanization in urban green areas. RESULTS: Intotal, 59 species and 1,465 individuals of butterflies were observed in the four urban green areas -Namsan Park(NS), Ewha Womans University (EW), Bukseoul Dream Forest (BD), and Hongneung Forest (HF) -anda natural forest, Gwangneung Forest (GF). The categories of land use around the study sites were determined based on GIS data. Species richness and density of niche breadth and habitat type in the four urban green areas differed mostly from those in GF. Estimated species richness and species diversity (H')in the four urban green areas were significantly lower than those in GF. Species richness and density of forest interior species and specialist species were positively correlated with paddy, field, and forest, whereas those of forest interior species and specialists were negatively correlated with urban area and road. Species composition and community structure of butterflies in the four urban were differed from those in GF. CONCLUSIONS: Theseresults suggest that decreases in paddy, field, and forest associated with the increased urban area and road negatively influenced species composition and changed butterfly communities.

Spatio-temporal change in forest cover and carbon storage considering actual and potential forest cover in South Korea.

This study analyzes change in carbon storage by applying forest growth models and final cutting age to actual and potential forest cover for six major tree species in South Korea. Using National Forest Inventory data, the growth models were developed to estimate mean diameter at breast height, tree height, and number of trees for Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi, Castanea crenata and Quercus spp. stands. We assumed that actual forest cover in a forest type map will change into potential forest covers according to the Hydrological and Thermal Analogy Groups model. When actual forest cover reaches the final cutting age, forest volume and carbon storage are estimated by changed forest cover and its growth model. Forest volume between 2010 and 2110 would increase from 126.73 to 157.33 m(3) hm(-2). Our results also show that forest cover, volume, and carbon storage could abruptly change by 2060. This is attributed to the fact that most forests are presumed to reach final cutting age. To avoid such dramatic change, a regeneration and yield control scheme should be prepared and implemented in a way that ensures balance in forest practice and yield.

Changes in butterfly abundance in response to global warming and reforestation.

In the Republic of Korea, most denuded forest lands have been restored since the 1960s. In addition, the annual mean temperature in the Republic of Korea has increased approximately 1.0 degrees C during the last century, which is higher than the global mean increase of 0.74 degrees C. Such rapid environmental changes may have resulted in changes in the local butterfly fauna. For example, the number of butterflies inhabiting forests may have increased because of reforestation, whereas the number of butterflies inhabiting grasslands may have declined. Furthermore, the number of northern butterflies may have declined, whereas the number of southern butterflies may have increased in response to global warming. Therefore, we compared current data (2002 approximately 2007) regarding the abundance of butterfly species at two sites in the central portion of the Korean Peninsula to data from the late 1950s and early 1970s for the same sites. Changes in the abundance rank of each species between the two periods were evaluated to determine whether any patterns corresponded to the predicted temporal changes. The predicted changes in butterfly abundance were confirmed in this study. In addition, the results showed a different response to habitat change between northern and southern species. In northern butterfly species, butterflies inhabiting forests increased, whereas those inhabiting grasslands declined. However, the opposite was true when southern butterfly species were evaluated. Changes in the abundance indicate that habitat change may be one of the key factors related to the survival of populations that remain around the southern boundary of butterfly species.

Change of abundance of arthropods in pine forests caused by aerial insecticide spray.

As pine wilt disease (PWD) spread rapidly throughout the Republic of Korea, pine stands were subjected to insecticide spraying that was gradually increased, which raised concerns regarding the negative impact of insecticides sprayed on nontarget organisms of pine forests. This study aims to estimate the changes in the abundance of arthropods caused by long-term insecticide spraying common in PWD-infected forests. Four pine stands were selected as sprayed and unsprayed sites in two locations in the southern regions of Busan and Gyongnam-do, showing the peaks of PWD epidemics. Beatings, sweepings, and pitfall trappings were used for collecting arthropods at the crown, undergrowth, and ground for 4 years, starting in May 2001. Long-term effects caused by yearly repeated insecticide treatments were not found to be related to changes in the abundance of arthropods, but short-term impacts within a year showed different influences according to habitats and functional groups.