Economics of Controlling Vertebrate Wildlife: the Pest-Asset Dichotomy and Environmental Conflict

Some wildlife species are agricultural pests (or otherwise a problem) but their populations are often valued by other than agriculturalists or by those not adversely affected by them directly. For non-farmers, the population levels of such wildlife are frequently pure public goods. This is one source of market failure in the economically optimal social control of an (agricultural) pest of this type. Secondly, if the species is geographically mobile, externalities occur between farmers (or other individuals) in the control of the species, and individuals ignore these spillovers in controlling pest species. Simple analysis is used to show that depending on the relative strength of these opposing types of market failure, farmers (or others) may excessively reduce or insufficiently decrease the population of a wildlife species from a social economic point of view based on the application of the potential Paretian improvement criterion. After providing some background on general methods of wildlife control and their effectiveness, the economic optimality of this control is assessed using simple models. The limitations of this modelling are then discussed paying particular attention to ‘newly emerging’ diseases in wildlife that in some cases impact humans, for example, Henipavirus carried by flying foxes.