Topographic Heterogeneity Outweighs Climate in Shaping Artemisia L. Species Richness and Endemism in the Hengduan Mountains, Southwest China

<i>Artemisia</i> L. (Asteraceae) is an important ecological pioneer genus and a widely used medicinal plant group. The Hengduan Mountains (HDMs), one of the most topographically complex regions in the world, support a high diversity of <i>Artemisia</i> species. Understanding the diversity patterns of <i>Artemisia</i> species in this region is essential for conserving plant resources and promoting their sustainable use. In this study, we identified the hotspots of <i>Artemisia</i> species richness and weighted endemism in the HDMs and examined how these patterns relate to topographic heterogeneity. We confirmed the distribution of 114 <i>Artemisia</i> species across the Hengduan Mountains. Our results show clear spatial variation in <i>Artemisia</i> species diversity. Distinct hotspots were found in areas such as the Minshan Mountains, Daba Mountains, Dadu River Valley, Daxue Mountains, and Mount Gongga. The top 5% richest grid cells showed high species richness and endemism, highlighting the ecological and conservation value of these regions. Environmental analysis indicates that topographic heterogeneity, especially elevation range and surface roughness, effectively predicts diversity patterns of <i>Artemisia</i> species. Regions with more complex terrain tend to support higher species richness and endemism. These findings underscore the key role of topography in shaping <i>Artemisia</i> species diversity in mountainous areas and provide a scientific basis for future ecological research and conservation planning.