Grassland use impacts on soil ciliate communities on the Qinghai-Tibetan Plateau

：Soil ciliates, crucial components of grassland ecosystems, serve as sensitive bioindicators of soil health and disturbance. This study investigates ciliate communities across four grassland use types on the Qinghai-Tibetan Plateau (QTP): seasonal and continuous grazing in natural grasslands (SGG and CGG), artificial perennial Elymus nutans Griseb. grasslands (PEG), and artificial annual Avena grasslands (AAG). Using live observation techniques, we identified 114 ciliate species from 10 classes and 21 orders, with Haptorida and Sporadotrichia emerging as dominant groups. Our findings reveal that grazing grasslands harbor greater endemic ciliate species richness compared to AAG. SGG and CGG exhibited significantly higher ciliate diversity (Shannon, Simpson, and Margalef indices) than other use types, while PEG and SGG supported higher ciliate abundances. Low Jaccard similarity indices between grassland types indicate distinct ciliate communities, reflecting management-induced environmental heterogeneity. Redundancy analysis identified above-ground biomass and soil pH as primary drivers of ciliate community structure. Notably, seasonal grazing (SGG) promoted the highest ciliate diversity, suggesting its potential as a sustainable management practice for maintaining soil health on the QTP. This research provides crucial insights into the relationship between land management and soil microbial diversity in high-altitude grasslands. Our findings support the implementation of moderate grazing practices to enhance soil quality and ecosystem resilience on the QTP, with implications for sustainable management of similar ecosystems worldwide.