Introduction

The conditions prompting people to change their patterns of resource use pose problems for those seeking to understand its dynamics. Common assumptions are that individuals invest in additional resources, new means, or find suitable substitutes primarily when their customary materials become scarce, when the costs to find and incorporate them become too expensive, or when appropriate incentives compel changes. How and why individuals or groups change their behaviour and thoughts about the products they depend upon has particular salience for conservation thinking and theory. This conundrum and the depiction of resource thresholds appealed to me from the beginning as natural resources are tangible in many Valley Bisa relationships. The accessibility, conditions, and maintenance of these products show in many aspects of people's lives from their initial appropriation to their uses and distributions for individual or collective purposes. For most residents, subsistence remains embedded within a dense web of ecological and social connections (Ellen 1982). Changes in life support stratagems affect pivotal social relations, such as social structure, division of labour, and property rights. Whether these transformations are quick or prolonged, their processes are dramatic and may often become tragic for many people (Schutkowski 2006).

Land use, locations of villages and settlements, censuses of residents together with their uses of natural resources within a 6km radius of the government school and the chief 's palace at Nabwalya were the objectives of earlier studies that began in 1966. Briefs on this area's local history, the distribution of villages and land uses, local diets, chronologies of subsistence activities, categories and stocks of natural resources as well as human impact on habitats and wildlife are all topics of earlier publications (Marks 1976). Beginning with the new wildlife programme in 1988, the long-term presence of large villages within the same space, coupled with an increasing human population stimulated by the infusion of new cash under a newly appointed chief, appeared to place residents there on the cusp of potential changes (‘tipping points’).