Disentangling conservation asymmetries through socio-economic transboundary factors across the Alto Paraná Atlantic Forest of South America

Ecoregions are often defined based on homogeneous biophysical and ecological conditions and are optimal spatial units for designing conservation strategies. However, transboundary ecoregions such as the Alto Paraná Atlantic Forest (APAF) experience asymmetrical conservation outcomes, understood here as cross-border differences, resulting from national land-use policies and socio-economic trajectories. 2. We integrated literature review and spatial analysis of social and ecological variables, such as population density, forest fragmentation, or protection levels, using an interdisciplinary approach. We measured conservation and socio-economic asymmetries by calculating pairwise Euclidean distances amongst these variables per pair of countries in the APAF ecoregion: Argentina, Brazil and Paraguay. We also generated and compared conservation and human development scores. 3. Despite being part of the same ecoregion, national borders have shaped distinct social-ecological systems with contrasting priorities and outcomes. Argentina was the most distinct system amongst APAF countries in terms of land use and forest conservation, while Brazil and Paraguay shared more similarities. This reflects better forest conservation in Argentina, although demographic, cultural and economic differences amongst the three countries are less pronounced. In political terms, Argentina and Brazil showed greater similarity, although all three countries have enacted policies to reduce deforestation; forest cover continues to decline throughout the region. 4. Additionally, our findings showed that in the Argentine APAF, forest conservation and human development, beyond economic metrics, are compatible goals. 5. Our results suggest that integrated approaches that combine ecological data with historical and socio-political factors are needed to guide effective cross-border forest conservation and sustainable development. We recommend incorporating local voices to capture cultural nuances and lived experiences to enrich the understanding of human-nature interactions, while fostering the international cooperation that reinforces conservation strategies in Argentina and prioritise ecological restoration in Brazil and Paraguay.