Pastoral governance hierarchies shape vegetation dynamics in Lebanon’s high-elevation rangelands

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Livestock grazing is often framed as a driver for biodiversity loss, but its ecological effects depend on the governance systems that mediate access to rangelands. While most studies focus on grazing intensity, little attention has been given to how governance hierarchies shape vegetation outcomes. We investigated plant community composition and specialization traits in the semi-natural tragacanth vegetation of Lebanon’s Sannine–Kneisseh Important Plant Area, testing whether increasing governance hierarchy is associated with floristic degradation. Using floristic data from 164 plots under three governance regimes (sovereign commons, private property rentals, and clan-brokered land access), we classified vegetation subtypes with Total Differential Value optimization and validated them using environmental variables and plant specialization traits. Governance type was significantly associated with floristic composition but not with species richness. Sovereign commons supported distinctive assemblages with minimal disturbance signatures, while clan-brokerage systems exhibited higher representation of synanthropic species and compositional degradation. Private property rentals showed intermediate patterns, reflecting both environmental context and landlord incentives. These findings highlight that degradation in high-elevation rangelands manifests more through shifts in composition than richness loss. We conclude that governance hierarchies mediate ecological sustainability in nuanced ways, and we recommend governance-sensitive co-designed interventions such as protected landscape approaches and plant micro-reserves, to protect biodiversity in Mediterranean mountain rangelands under increasing land-use pressure. ● Governance hierarchies shape floristic composition in Lebanese rangelands ● Species richness is stable, but disturbance indicators shift with governance ● Sovereign commons support unique assemblages with minimal disturbance ● Hierarchical brokerage appears to stabilize land area but accelerates degradation ● Governance-sensitive tools, such as Plant Micro-Reserves can safeguard diversity