Paying for the provision of environmental services is a recent policy innovation attracting much attention in both developed and developing countries. This innovation, referred to as ‘payments for ecosystem services’ (when the emphasis is on enhancing ‘nature’ services) or ‘payments for environmental services’ (when amenities provided by the built environment are also included) is referred to here as PES. PES programs aim to harness market forces to obtain more efficient environmental outcomes. Since so many opportunities for PES programs could involve farmers in poor regions, international aid agencies and private donors, looking for a double dividend, increasingly consider using PES programs as a potential way of meeting both social and environmental objectives.

Traditional grazing grounds near Amboseli National Park (Kenya) are being rapidly converted to cropland – a process that closes important wildlife corridors. We use a spatially explicit simulation model that integrates ecosystem dynamics and pastoral decision-making to explore the scope for introducing a ‘payments for ecosystem services’ scheme to compensate pastoralists for spillover benefits associated with forms of land use that are compatible with wildlife conservation. Our break-even cost analysis suggests that the benefits of such a scheme likely exceed its costs for a large part of the study area, but that ‘leakage effects’ through excessive stocking rates warrant close scrutiny.