Abstract: Casuarina equisetifolia, the predominant tree species in coastal shelter forests of southern China, is known for its rapid growth, strong sprouting ability, high-temperature tolerance, and effective windbreak performance. Predicting suitable habitat patterns under current and future climate scenarios is crucial for establishing coastal shelter forests in southern China. Utilizing the data from 793 distribution sites of C. equisetifolia across China and various environmental factors, we used the Maxent model to determine the current distribution pattern of C. equisetifolia under existing climate conditions, as well as its potential geographical distribution under future climate change scenarios SSP2-4.5 and SSP5-8.5. The results showed that: (1) the Maxent model exhibited high accuracy, with an area under curve value of 0.979. Environmental factors, such as the active accumulated temperatures of ≥10 ℃ and the highest temperature in the coldest month, significantly affected the distribution of C. equisetifolia. (2) Under the current climatic conditions, the suitable area for C. equisetifolia was 35259 km², with a northern boundary at 30.24°N. The optimal distribution area was 2951 km², with a northern boundary at 28.69°N. (3) In the late 21st century, under the SSP2-4.5 and SSP5-8.5 scenarios, the area suitable for the distribution of C. equisetifolia is projected to decrease by 26.1% and 20.2%, respectively, with the northern boundary shifting southward by approximately 0.9° latitude. In these two scenarios, the optimal distribution area for C. equisetifolia is projected to increase by 239.8% and 213.5%, respectively, with the northern boundary shifting southward by approximately 3.4° latitude.

Key words: Casuarina equisetifolia, potential distribution, future climate scenario, Maxent model