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Invasive species are significant threats to biodiversity, natural ecosystems andagriculture leading to large worldwide economic and environmental damage. Spreadand control of invasive species are stochastic processes with important spatialdimensions. Most economic studies of invasive species control ignore spatial andstochastic aspects. This paper covers this gap in the previous studies by analysing aspatially explicit dynamic process of controlling invasive species in a stochasticsetting. We show how stochasticity, spatial location of infestation and control caninfluence the spread, control efficiency and optimal control strategies. The main aimof this paper is to analyse the relationship between economic parameters andstochastic spatial characteristics of infestation and control. In the model used, thereare two ways to control infestation: border control, under which the spread ofinvasive species from any of its infested neighbouring cell is prevented, and cellcontrol, which removes the infestation from the existing cell. An integer optimisationmodel is applied to find the optimal strategies to deal with invasive species. Resultsshow that it is optimal to eradicate or contain for a larger range of border control andcell control costs when the invasion is in the corner or on the edge as compared to thecase where the initial infestation is in the middle of the landscape. Decrease in theprobability of successful border control makes containment an unfavourable controloption even for low border control costs. We show that decrease in the rate of spreadcan result in switching optimal strategies from containment to abandonment ofcontrol, or from eradication to containment. We also showed when the probability ofsuccessful cell control decreases, a lower eradication cost is required for eradicationto remain the optimal strategy. In summary, this paper shows that in order to avoidproviding misleading recommendations to environmental managers, it is important toinclude uncertainty in the spatial dynamic analysis of invasive species control.
