The human fingerprint of medicinal plant species diversity

Medicinal plants have been integral to human cultures for millennia and have played a central role in the development and expansion of societies.¹ These plants are pivotal for ongoing pharmaceutical research and drug development,^1,2,3 contribute to ecosystem health,⁴ and support myriad cultural traditions and the global economy.^4,5,6 Despite their importance, however, the factors influencing the global diversity and distribution of medicinal plants remain underexplored. Their diversity, like that of other species groups, is shaped by abiotic and biotic influences, which include, in unique ways, human ecological (including cultural) practices. A key unexplored topic is whether variation in the duration of human interactions with a flora has influenced regional heterogeneity in medicinal plant knowledge and diversity. Here, we investigate and compare these influences on the distribution and diversity of 32,460 medicinal plant species and on global vascular plant distributions. We identify significant regional variation in medicinal plant diversity, including "hotspots" (India, Nepal, Myanmar, and China) and "coldspots" (the Andes, New Guinea, Madagascar, the Cape Provinces, and Western Australia) of diversity. Regions with long histories of human settlement typically boast richer medicinal floras than expected. By contrast, language diversity, an indicator of cultural diversity, has a limited direct connection to medicinal plant diversity, but its indirect associations warrant further exploration. Our study emphasizes the need for integrated conservation strategies that incorporate both standard ecological factors and human ecological dimensions. The latter are critical not only for understanding but also for preserving medicinal plant resources and enhancing global healthcare solutions.