Conservation effectiveness of public trusteeship: A multiscale evaluation of Xianghai Nature Reserve in Northeast China.

Effective management of protected areas is essential for biodiversity conservation, yet the ecological outcomes and social constraints associated with commonweal organizations remain poorly quantified. From 2016 to 2023, a commonweal protected area model was implemented at Xianghai National Nature Reserve in the agro-pastoral ecotone of Northeast China. Under a public trusteeship agreement, land ownership and contract rights remained with local collectives and farmers, while conservation and management responsibilities were transferred to the Paradise Ecological Conservation Foundation. Using multi-temporal land-cover data, vegetation plot surveys, and infrared camera monitoring, we evaluated how this trusteeship reshaped landscape structure and influenced zonal plant regeneration. Between 2000 and 2020, wetland area increased nearly ten-fold, water bodies expanded by 62%, along with landscape diversity, while cropland dominance and aggregation declined, indicating a shift toward greater landscape heterogeneity. However, ecological responses were non-synchronous. Supported by hydrological regulation and water diversion projects, wetlands recovered rapidly, whereas regeneration of Mongolian elm (Ulmus macrocarpa var. mongolica) lagged in areas subject to higher disturbance, particularly those near livestock grazing. Camera-trap data showed that while trusteeship curtailed some agricultural activities, it had limited influence over grazing and routine human movements, which continued to shape regeneration patterns. We concluded that public trusteeship can function as an effective short-term management approach to reverse acute ecological degradation, but its long-term viability might be constrained by external funding and limited leverage over grazing activities. Sustaining similar schemes will require a shift toward co-management frameworks that integrate local livelihoods.