Changes in the Suitable Habitat of the Smoke Tree (Cotinus coggygria Scop.), a Species with an East Asian-Tethyan Disjunction

The smoke tree (Cotinus coggygria Scop.) is a woody species mainly distributed in the Mediterranean region and East Asia, known for its high ecological and ornamental value. Investigation of changes in suitable habitats under different conditions can provide valuable insights with implications for predicting the distribution of C. coggygria. In this study, we employed a MaxEnt model to simulate the current, historical, and future suitable habitat of C. coggygria using distribution records and environmental variables. The results indicated that climatic variables had a much stronger impact on the suitable habitat of this species compared with soil and topographic variables, and bio11 (mean temperature of the coldest quarter) and bio12 (annual precipitation) played particularly important roles in determining the suitable habitat. The core distribution of C. coggygria exhibited an East Asian-Tethyan disjunction. During the glacial period (Last Glacial Maximum), C. coggygria in Europe was concentrated in the glacial refugia in southern Europe; its range was substantially smaller during the glacial period than during interglacial periods (mid-Holocene). In contrast, C. coggygria in East Asia survived in regions similar to those of the interglacial period. Future climate change led to a gradual northward expansion of suitable habitats for C. coggygria, and the area of suitable habitat was substantially larger in Europe than in East Asia. There were significant differences among the four climate scenarios in Europe, with minimal variation in East Asia. Our findings provide valuable insights into the contrasting effects of climate change on European and East Asian populations of C. coggygria, which enhances our understanding of Eurasian species with discontinuous distributions.