This research examines the impacts of coca leaf cultivation (an ingredient for cocaine paste) on land-use and land-cover change (LULCC) in a colonised, humid-tropical forest area of central Bolivia. The socio-economic driving forces affecting the way farmers have utilised their land and the resulting effects on land-cover change are studied. Satellite imagery from 1975 to 2000, methods of participatory rural appraisal and socio-economic data has been combined to determine deforestation patterns, changes and the driving forces of LULCC. Three communities were studied: Arequipa, dominated by coca production and alternative development crops; Bogota, a cattle rearing community; and Caracas where fruit cultivation dominated. Three major periods were determined from a land-management synopsis in each community: (i) pre-coca dominant, driven by weak national policies and economics, with high rates of deforestation; (ii) coca-dominant, influenced by the international coca / cocaine economy, with the lowest rates of forest clearance; and (iii) post coca-dominant, driven by strong international anti-narcotics policies, when forest clearance accelerated again. The deforestation trajectories (rates) differ from published models and the variations are attributed to the rising dominance of coca being ascended by an enforced substitute economy. These driving forces have been conceptualised at local, national and international levels. Specific fragmentation patterns developed because of the spatial arrangement of plots planned in the 1960s and the subsequent variations in land-use management strategies between, as well as, within individual plots over time. A five stage conceptual model has been constructed to represent forest fragmentation at the community level. Overall, in the pursuit of global social gains, anti-narcotics policies caused rapid consumption of limited land resources and because of non-conservationist planning the connectivity between montane and humid tropical forests at the margins of a biodiversity hotspot is severely compromised -a message to planners and policymakers where conservation and development currently conflict in humid tropical regions.