This paper is the first to examine the public economics of exportbased externalities arising within the provisioning of ecosystem services, with direct application to policies to prevent the spread of hitchhiking invasive species. We find when risk enters through exports, policy makers face a tradeoff between welfare improvements and reducing risk of invasion. Estimates of visitor demand elasticity for ecotourism are low, so price policies are not likely to reduce risk, though they can raise tax revenue. If demand is elastic enough to reduce risk, trade effects can cause loss of income greater than the risk of the invasion. The paper is motivated by the expansion of invasive species' within the United States. We apply our model to the specific example of quagga and zebra mussels invasion into the U.S. Pacific Northwest.