Comment: The Economics of Interdependent Renewable and Non-renewable Resources revisited.

This work expands upon Swallow's theoretical analysis of interactions between renewable and non-renewable resources. In this comment the interaction is such that the renewable resource prefers the non-renewable environment, as opposed to SwallowÕs (op cit) case of the non-renewable environment being essential to the renewable resource. We find that this difference strongly affects the results, and makes the resources change from being complements to being substitutes, i.e. in the essential case profits from active development of the non-renewable resource come at the cost of reducing the optimal stock level for the renewable resource, while a preferred habitat implies the impacts of development can be offset by allowing for a larger renewable stock level.