Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences and their collaborators revealed that plant community turnover and nematode body width play fundamental roles in shaping soil nematode diversity across different spatial scales. Their findings highlight that protecting the variety of plant species is essential for preserving nematode diversity and that a nematode’s body width largely determines how it spreads across the environment.