Local Institutions Mediate Effects of Land Scarcity in Indigenous Territories in Amazonia

Indigenous territories in Amazonia sustain forest cover through the practice of swidden-fallow agriculture, yet declining land availability threatens both the ecological sustainability of this agricultural system and its contributions to community livelihoods. While scholars recognize land scarcity’s potential to drive transformations in shifting cultivation systems, we lack a systematic understanding of how local institutional frameworks shape heterogeneous responses to resource constraints. This study examines how land access mechanisms, distribution dynamics and property regimes among Indigenous communities mediate experiences of and adaptations to land scarcity in the Peruvian Amazon. We conducted a comparative case study of Solidaridad and Tamboruna, two land-scarce Indigenous communities in Peru’s Napo River basin, employing mixed methods including household surveys (n = 74), plot-level assessments, and qualitative interviews with community leaders. Our findings reveal three critical pathways through which institutions mediate scarcity outcomes. First, land access mechanisms determine whether scarce resources produce equitable constraint or acute land inequality. Second, land use intensification emerges not from scarcity alone but from accumulated inequality and household labor capacity, with land accumulated over lifecycles showing stronger associations with management practices than initial endowments. Third, where scarcity manifests as extreme polarization, it precipitates renegotiation of land property norms shaped by Indigenous sociability and moral economies, defying straightforward trajectories toward either resource privatization or collective governance. These results demonstrate that land scarcity produces divergent trajectories mediated by community-specific institutions, with swidden-fallow systems likely diminishing their capacity to sustain forest regeneration in Indigenous communities where scarcity leads to acute land inequality. Rather than uniform solutions, sustainability policy must therefore tailor interventions to local institutional contexts—prioritizing territorial expansion, facilitating communities’ own governance development, and supporting household adaptive capacity to resource scarcity.