Temperature and ant assemblages: Biased values of community temperature index

The community temperature index (CTI) is increasingly used to identify the impacts of global warming on local biotic communities such as birds, butterflies, and plants. Temperature is one of the main determinants of global ant diversity and local ant assemblages. Therefore, the CTI can be used to identify the relationship between temperature and ant assemblages or to estimate the influence of global warming. This study aimed at finding the relationship between temperature and CTI values of ant assemblages. Ants were surveyed using baits and pitfall traps at six forest sites in South Korea, differing in mean annual temperature (MAT) from 7.4 °C to 12 °C. The national ant data was used to calculate the species temperature index (STI) of each species that was then used to estimate CTI. The CTI values were significantly positively correlated to MAT values, but the slopes of regression models were lower than one (0.43–0.62). The low slope might be partly caused by the bias of local occurrence data: Overestimation of STI of northern species and underestimation of southern species. The slope values varied according to data types (abundance-individuals, abundance-trap, and occurrence).