Socio-ecosystems are described as complex adaptive systems. Public policies aimed at influencing such systems, if considered inappropriate by local stakeholders, will be undermined by the emergence of alternative strategies subverting the proposed changes. Applying this concept to the field of natural resources management, in this paper we report how a set of laws and tenure rights aimed at protecting native species in a complex multi-strata agroforestry system actually could achieve the opposite result. We focus on Kodagu district in the Western Ghats of India. Kodagu produces 2% of the world's coffee, mainly in small holdings (<10 ha). In an assessment of 114 coffee estates spread across the landscape, we identified over 240 tree species, both native and exotic, making this production system one of the most diverse in the world. This allows for cautious optimism regarding biodiversity conservation in human-modified landscapes. Yet over the last 20 years, intensification of the same production systems has resulted in gradual thinning of the shade cover and replacement of native trees with fast growing exotics, primarily Grevillea robusta. This replacement has been happening despite the existence of a framework of land and tree tenure rights and legal constraints designed to protect native species and the resources that they represent. Interactions between this framework and market forces driving intensification via coffee prices, wood demand, need for pepper stands, labour and input costs, have contributed to make G. robusta the obvious choice, at the expense of the native species that the framework was supposed to protect. Based on this scenario we explore alternative strategies that would tilt the balance in favour of native species without limiting the livelihood options of local farmers. Such alternatives, if developed endogenously may be more acceptable and therefore more likely to attain the original objective of conserving native species. (Texte intégral)