Coexistence of biocrusts with vascular plants shapes semiarid dryland multifunctionality

Drylands host complex biocrusts and vascular plant communities, and these ecosystems are vital to human wellbeing, global ecosystem sustainability, and vegetation management; they support multiple ecosystem functions simultaneously across half of our planet. However, studies on the influence of biocrust-plant interactions on multifunctionality in their coexisting state are lacking, limiting the predictability of global drylands resilience under future climate change accurately. Here, we investigated biocrusts from the Loess Plateau of China. We performed a two-year in situ experiment to explore how biocrust-vascular plant interactions affect ecosystem multifunctionality across four key functions in removed biocrusts (shrub and grass) and intact biocrusts (mixed moss and shrub/grass) ecosystems. Vascular plants, particularly grasses, contributed most to dryland ecosystem functioning. However, the combination of intact biocrusts and vascular plants significantly reduced primary productivity, carbon sequestration, nutrient supply and cycling, water and climate regulation, and biodiversity maintenance compared with vascular plants in removed biocrusts plots. The ecosystem multifunctionality index further supported this finding and showed that mixed patches of biocrusts and shrub/grass plants significantly reduced the ecosystem multifunctionality compared with vascular plants of removed biocrusts. Our short-term biocrust removal experiments suggests that potential competition between vascular plants and biocrusts may limit multifunctionality in the semiarid dryland. Therefore, future studies can help elucidate the role of non-vascular and vascular plant competition in supporting functions during global changes, which is necessary for better management of vegetation restoration in dryland ecosystems in the future.