Abstract

Many harmful invasive species colonize large spatial areas that include a diverse range of habitats. While a large bioe-conomic literature addresses spatial-dynamics of invasive species management, limited attention is given to spatial hetero-geneity of an invasion and its implications for the design of cost-effective control design. Potential sources of spatial hetero-geneity include natural factors such as the local assemblage of native species. Other sources are socioeconomic, for example the distance of an area from the nearest population center. Of particular concern for management is when spatial heteroge-neity leads to a refuge effect: partial or complete protection from one or more methods of control. This paper introduces a stylized spatial-dynamic bioeconomic model of invasive species management in the presence of a refuge effect. A decision maker minimizes the net present value of invasion damage and management costs by specifying control across space and time. The model is tailored to the case of invasive lionfish (Pterois spp.), predatory marine species known to infest deep water areas beyond the reach of control by divers. Other control techniques than can access lionfish in these depth refuges are likely to generate damage in the form of native species bycatch. Analytical results from control theory characterize the influence of economic and biological model parameters on the optimal policy. Numerical results explore the influence the refuge effect when only one control method is available, and the trade-off between invasion damage avoided and bycatch when a second non-selective control method is introduced.

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