Evaluation of moth community changes and northward shifts in response to climate warming in Korea using both local and global occurrences

Although climate warming arguably induces changes in species distribution, thereby causing poleward shifts in various taxa, comprehensive research on the response of moths to climate warming is lacking. This study compared the distribution of macro-moths between historical (1978–2002) and recent (2011–2016) periods in South Korea using the macro-moth data collected at 18 survey sites to elucidate the changes in community composition. We used the community temperature index (CTI) to quantify the effect of temperature change on moth community changes. The CTI represents the average value of the species temperature index (STI; mid-value of thermal range) calculated using our local observations and global occurrences reported in the online database of the Global Biodiversity Information Facility. Our analysis revealed no significant difference in species richness between historical and recent surveys. However, some taxa, such as Uraniidae, Nolidae, Sphingidae, and Lasiocampidae, exhibited high turnover rates, while the number of sphingid moths with large body sizes greatly decreased. The temperature changes at the survey sites became pronounced with an increase in the survey interval (year) between historical and recent surveys (temperature increase = 0.0465 ℃ /year), while the CTI change exhibited a weak signal for northward shift of moth species. The CTI using the local data indicated 0.09 km/year of northward shift of moths, which is considerably slower than the northward shift (9.6 km/year) of the isothermal bands. However, the CTI using global occurrence data, expected to improve the estimation of species thermal niches, did not show any sign of northward shift. When observed, the northward shifts of moths were primarily identified in the cold-adapted species with low STI values, suggesting that cold-adapted species are more sensitive and vulnerable to climate warming than warm-adapted species. These results indicate that the current distribution changes of species were uneven, and the species adapted to cold regions are the ones primarily responding to the temperature increase by migrating northward and to high elevations.