Despite the many benefits natural forests provide, they are being lost worldwide at unsustainable rates as development frontiers expand. One approach to improving the efficacy of natural forest conservation efforts is to refine local forest conservation policies based on insights from the place-based study of conservation policies and land-use and land-cover change (LULC) dynamics. To demonstrate the strength of this approach, this research explores the dynamics of LULC and conservation policies on the forest frontier of Madre de Dios, Peru. The main objectives of this research are to evaluate the efficacy of designated conservation lands in a rapidly expanding frontier landscape and to assess the effect on ecosystem conversion of granting conflicting land-use designations, such as mining concessions, inside conservation areas. Using statistical matching and a GIS-based analysis of LULC, this research shows that for the period 2006–2011, designated conservation lands on the forest frontier of Madre de Dios significantly reduced ecosystem losses compared to non-conservation lands, but the effect was highly variable across conservation designations. Also, when present, conflicting land-use authorizations inside conservation areas, specifically overlapping mining and agricultural titles, eliminated the policy additionality of designating lands for conservation. This finding demonstrates that authorizing conflicting land-use rights inside conservation areas should be avoided to ensure intended land conservation outcomes. This case study also provides examples of how local forest conservation policies can be improved through detailed and frequent analyses of LULC and conservation policies, particularly in dynamic frontier landscapes where LULC and socio-economic conditions are rapidly changing.