Policy Implementation Challenges of UNESCO's Man and the Biosphere Program, Illustrated by Science–Society Interactions in 18 Mountain Biosphere Reserves

Mountain regions are increasingly vulnerable to the converging global crises of climate change, biodiversity loss, and land degradation. These socioecological challenges demand not only incremental adaptation but also broader societal transformation processes, including in knowledge production. Science–society interactions (SSIs) are increasingly recognized as a promising pathway toward the coproduction of context-specific, actionable knowledge that can support such transformations. In recent years, the United Nations Educational, Scientific and Cultural Organization's (UNESCO's) Man and the Biosphere (MAB) program has positioned its biosphere reserves (BRs), most of which are in mountain regions, as model sites for sustainability transformations and for advancing SSIs. However, despite a strong emphasis on SSIs in MAB policy directives, little is known about whether and how these have been implemented in practice. This paper investigates the policy implementation gaps between the aims of the MAB program and reality on the ground, based on qualitative content analysis of periodic review reports from 18 mountain BRs across Africa, Australia, Europe, and North America and 14 semistructured interviews with BR representatives. Findings reveal that SSIs in mountain BRs remain predominantly ecology-focused, characterized by one-way, short-term information transfer, with limited involvement of local actors or incorporation of nonacademic knowledge. Main challenges to the international policy goals include resource and capacity constraints, weak institutional anchoring, fragmented governance, and sociopolitical resistance. Although participatory approaches are widely valued, their practical execution remains challenging. The results underscore the need for context-sensitive policy frameworks, increased resources, and capacity-building to strengthen mountain BRs as model regions for SSIs and sustainability transformations.