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Journal of Environmental Management 89 (2008) 271–272 www.elsevier.com/locate/jenvman
Introduction: Special issue on the economics of invasive species management This issue brings out some of the current thoughts on the economics of invasive species management. Through seven articles, it presents a collection of both empirical and theoretical works that explore various means to tackle the invasive species problems which threaten our agriculture and natural resources. Two of the papers in this issue deal with the important issue of managing invasive species at the port of entry; two papers do a bio-economic analysis for evaluating optimal strategies under risk and the timing of such strategies; one paper looks at the optimal harvesting of invasive species for obtaining value of information when the pest population is uncertain; one derives the distribution function for invasive species, arrival through existing data to analyse implications for detection efforts; and one looks at the valuation of ecological damages from invasive species. Each invasive species presents its own set of unique challenges that is tied to its environment of origin and destination, biological characteristics, nature and extent of economic and ecological resources at risk, etc. Yet, the fundamental decision issues always involve spending costly resources to contain or eradicate them when there is limited information. When uncertainty is a key factor involved in decision-making, the timing, extent and robustness of decisions, generation of new information, and managing asymmetric information may have crucial implications for the success rate of invasive species management. These are precisely the issues that have been given special attention to in this special issue. In the ﬁrst paper, Ranjan et al. examine the optimal management of a renewable resource that is at risk from alien species invasion. The objective of this paper is to derive implications for optimal management of a resource when options exist for both preventing the arrival of an invasive species and mitigating the impact after arrival. Uncertainty about the timing and nature of an invasion can have important implications for the choice of management strategy, and a key feature of this analysis is an explicit treatment of that uncertainty. The second paper by D’evelyn et al. asks whether control efforts could be used as an alternative to decipher the population stock of invasive species in the case when the 0301-4797/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2007.05.021
effort-harvest function is stochastic but known. Early control efforts yield valuable information related to population size besides controlling the uncertain stock. They apply this idea to the study of brown tree snake control on the island of Saipan, located north of Guam. Mofﬁtt et al. design robust inspection protocols related to border inspections, a criterion that maximizes the range of uncertainty over which the damages from invasive species are restricted while meeting a budget constraint. Their approach offers another alternative to existing options for prevention. They do a numerical illustration of their idea for containerized agricultural cargo requiring inspection prior to entry into a country. Areal et al. use the market for UK import of speciﬁc genera of cut ﬂowers from Kenya between 1996 and 2004 as an example to study an invasion pathway along which species of non-indigenous plant pests can travel to reach new areas. Using the count data model they test for several models that ﬁt species, arrival patterns. They highlight the importance of knowing the link between pest detection and the Genus of cut ﬂower imported, as in some cases detection effort could be reduced without increasing the risks of species arrival and establishment. Fernandez looks at two emissions vectors in the shipping industry—ballast water and biofouling, to address risk of damages under asymmetric information between the regulator and the shipper. She ﬁnds that incentive-based policies (subsidy with liability rule or tax with liability rule) are efﬁcacious in avoiding marine invasive species pollution. Grimsrud et al. examine the beneﬁts of early detection and prevention of invasive weeds on grasslands. They ﬁnd that the size of the incentive that is needed for weed management through private participation is dependent upon the level of infestation. Timing of incentives is crucial as higher incentive payments for lower levels of weed infestations reduce the total cumulative incentive payments over time. The ﬁnal paper of this issue deals with valuation of environmental damages by invasive species. The paper by Wilgen et al. estimates damages from 56 current and potential invasive species to the ecosystem of South Africa.
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Editorial / Journal of Environmental Management 89 (2008) 271–272
The services considered are surface water runoff, groundwater recharge, livestock production and biodiversity. They ﬁnd that the future damages from invasive species could be much higher than the current ones.
Guest Editor, JEM Ram Ranjan Economist, CSIRO, Perth, WA, Australia E-mail address: [email protected]