Characterised and Projected Costs of Nonindigenous Species in Canada

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<ul><li><p>Characterised and projected costs of nonindigenous species in Canada</p><p>Robert I. Colautti*, Sarah A. Bailey, Colin D.A. van Overdijk, Keri Amundsen&amp; Hugh J. MacIsaacGreat Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4,Canada; *Author for correspondence (e-mail: colautti@botany.utoronto.ca; fax:+1-519-971-3616)</p><p>Received 8 January 2004; accepted in revised form 26 March 2004</p><p>Key words: agriculture, Canada, damage costs, economic impact, sheries, forestry, invasive speciesinvisible tax, nuisance NIS, nonindigenous</p><p>Abstract</p><p>Biological invasions by nonindigenous species (NIS) can have adverse eects on economically importantgoods and services, and sometimes result in an invisible tax on natural resources (e.g. reduced yield).The combined economic costs of NIS may be signicant, with implications for environmental policy andresource management; yet economic impact assessments are rare at a national scale. Impacts of nuisanceNIS may be direct (e.g. loss of hardwood trees) or indirect (e.g. alteration of ecosystem services providedby growing hardwoods). Moreover, costs associated with these eects may be accrued to resources andservices with clear market values (e.g. crop production) and to those with more ambiguous,non-market values (e.g. aesthetic value of intact forest). We characterised and projected economic costsassociated with nuisance NIS in Canada, through a combination of case-studies and an empirical modelderived from 21 identied eects of 16 NIS. Despite a severe dearth of available data, characterisedcosts associated with ten NIS in Canadian sheries, agriculture and forestry totalled $187 millionCanadian (CDN) per year. These costs were dwarfed by the invisible tax projected for sixteen nuisanceNIS found in Canada, which was estimated at between $13.3 and $34.5 billion CDN per year. Canadaremains highly vulnerable to new nuisance NIS, but available manpower and nancial resources appearinsucient to deal with this problem.</p><p>Introduction</p><p>Technological advances in transportation and lib-eralised international trade allow rapid movementof people and goods throughout the world. Anunintended consequence of this unprecedentedlevel of human activity has been intentional andaccidental introductions of nonindigenous species(NIS) beyond their native ranges (Mack et al.2000). Despite increasing public awareness, thenumber of new invaders continues to increase infreshwater, marine, and terrestrial ecosystems inNorth America and elsewhere (Sailer 1983; Cohen</p><p>and Carlton 1998; Ruiz et al. 2000; Ricciardi2001). This pattern may in part be the result ofincreased vigilance by scientists, but available evi-dence suggests that the pattern is real (Ruiz et al.2000; Ricciardi 2001; Simons 2003). Many NISpositively aect human welfare or appear rela-tively harmless, while others have eects that arewholly undesirable; it is of course the latter groupwith which invasion biologists, resource managersand policy makers take interest (Mack et al. 2000;Simberlo 2003).Numerous denitions have been used to des-</p><p>cribe NIS that have negative impacts, including</p><p>Biological Invasions (2006) 8: 4559 Springer 2006DOI 10.1007/s10530-005-0236-y</p></li><li><p>invasive, noxious, nuisance, pest, andweed. The term invasive in particular has beenproblematic, as biologists typically use it in refer-ence to species that spread quickly or are wide-spread in distribution, whereas policy makers useit to imply negative economic, health, or ecologi-cal eects (see Richardson et al. 2000). To main-tain consistency between uses, we employ theterm nuisance NIS herein to describe speciesintroduced beyond their native range that haveadverse consequences for economic, environmen-tal or human welfare.Understanding the magnitude of economic</p><p>costs associated with nuisance NIS is importantfor environmental policy and management, yetfew studies have evaluated the cost of NIS tonational economies. An examination of 79 estab-lished NIS in the United States estimated eco-nomic losses of about $96.9 billion in UnitedStates dollars (USD) between 1906 and 1991(OTA 1993). More recently, in well-publicisedstudies, Pimentel et al. (2000, 2001) estimatedtotal damage and control costs of $137 billionUSD per year for all NIS in the United States,and collectively more than $314 billion USD peryear in the USA, United Kingdom, Australia,South Africa, India and Brazil. Application ofPimentel et al.s (2000) model to Canada sug-gested that damage caused by nuisance NISamounts to $7.5 billion Canadian dollars (CDN)per year (Dawson 2002).Most assessments of economic costs have</p><p>been limited to specic NIS within particularlocalities, and have considered only direct costsassociated with control or loss of marketablegoods or services. More inclusive models ofeconomic costs of nuisance NIS are dicult todevelop owing to a dearth of data pertaining toindirect market costs, as well as both direct andindirect, non-market costs (e.g. reduced aestheticvalue). Canadas forests, agricultural systems,and aquatic ecosystems have been invaded byat least 1442 species (MacIsaac et al. 2002), yetno attempts have been made to quantify theeconomic impacts of these NIS. Here we reportthe results of a study commissioned by theOce of the Auditor General of Canada todetermine the economic impact of nuisance NISin agriculture, forestry and aquatic sectors inCanada.</p><p>Materials and methods</p><p>Identifying economic impacts of nuisance NIS isencumbered by a number of challenges. Forexample, partitioning the eects of synergisms(i.e., non-additive interactions) between NIS andnative species, and between species invasions andother environmental stressors (e.g. habitatchange, over-harvesting, climate change) can bevery dicult (e.g. OTA 1993; Parker et al. 1999;Simberlo and Von Holle 1999; Smith et al.2000; Harris and Tyrrell 2001; Stachowicz et al.2002). More importantly, introduction of nui-sance NIS may impart externality costs, whichare expenses incurred to parties that were notinvolved with the transaction responsible for theintroduction of the species. Externality costs mayresult from direct activity associated with the nui-sance NIS, or as an indirect by-product of itspresence. Furthermore, these externalities mayimpact either market or non-market goods andservices. Most costs associated with NIS intro-ductions are external, but deliberate introduc-tions may include internalised costs. Forexample, numerous game shes have been intro-duced deliberately throughout North America(Fuller et al. 1999), but prots gained by recrea-tional sheries may be partially oset by internalcosts associated with displaced native gameshes.Externality costs, direct/indirect eects, and</p><p>market/non-market values are exemplied byzebra mussel (Dreissena polymorpha) invasions inthe Laurentian Great Lakes (Figure 1). Zebramussels were accidentally introduced by transcon-tinental, commercial shipping, which generatedan externality to the electrical power industry(among others) when waterworks facilitiesbecame infested with mussels. Aected companiessustained reduced power generation while pipeswere clogged, and subsequently implementedcostly antifouling systems (i.e., direct marketcosts; Figure 1) (LePage 1993). At the same time,some municipalities experienced poor water qual-ity owing to an o-taste generated by presence ofgeosmin, a compound generated by macrophyteswhich grew in profusion as a result of zebramussel-induced increase in water clarity (seeMacIsaac et al. 2002). The City of Windsor, Ontario,for example, spent between $400,000450,000</p><p>46</p></li><li><p>CDN per year for activated charcoal treatment toeliminate taste and odour problems from munici-pal water supplies after zebra mussels invadedLake St. Clair, upstream of the citys water intakeline (i.e., indirect market cost; Figure 1). Moregenerally, direct costs of nuisance NIS mayinclude enhanced control or management costs,as well as human health eects (Mack et al.2000). Nuisance NIS also may impose an invisi-ble tax on natural resources and national econo-mies by reducing the production of naturalresources (Mack et al. 2000; Perrins et al. 2000).Pimentel et al. (2001) estimated that this taxmay exceed $1.4 trillion USD per year worldwide.Non-market costs associated with nuisance NIS</p><p>are usually not considered in assessments of eco-nomic damage, perhaps because they are muchmore dicult to quantify (Figure 1). These costsmay be related to changes in biodiversity of, orchanges to, natural habitats caused by NIS. Forexample, nonindigenous weed species like cheat-grass (Bromus tectorum), leafy spurge (Euphorbiaesula), spotted knapweed (Centaurea maculosa)and purple loosestrife (Lythrum salicaria) alterphysical and/or chemical attributes of aectedhabitats, rendering them less suitable to nativespecies (e.g. Bais et al. 2003). Although invasionsmay have no direct economic consequence, theymay nevertheless reduce economically importantecosystem services like the prevention of soil ero-sion, water detoxication, and consumption ofcarbon dioxide by growth of native vegetation.For example, non-market costs associated withinvasion of zebra mussels in the lower GreatLakes include extirpation of native unionid</p><p>mussels owing to fouling (direct eect) and lossof preferred turbid-water habitat for some nativesh through the biodeposition of particulate mat-ter (indirect eect) (Figure 1; MacIsaac 1996).To calculate the non-market value of natural</p><p>ecosystems, researchers may utilise contingentvaluations in which an assessment is made of anindividuals willingness to pay. This approachenables a nancial assessment of environmentalnon-market goods and services (e.g. aestheticvalue, space for recreational activities), but issubjective, likely to vary among interest groupsand geographic areas, and is considered contro-versial in consequence (Turner et al. 1998). Per-haps the largest stumbling block in calculatingthe costs of habitat degradation is the lack of agenerally accepted theory of ecosystem value(Patterson 1998). Without an accepted valuationsystem it is impossible to develop a model toaccurately estimate damages associated withcompromised ecosystems. However, by examin-ing the market values of goods and services pro-duced by ecosystem processes, we can explore thepossible costs associated with ecosystem disrup-tion caused by nuisance NIS.No studies exist that systematically assess even</p><p>the direct costs associated with nuisance NIS inCanada. In a rst attempt to gauge the impact ofnuisance NIS to Canadas economy, we reviewedavailable data on the direct and indirect costsreported for thirteen of Canadas most notoriousinvaders. In some cases, we extrapolated charac-terised costs for particular regions to other areasin which particular NIS were found, but whereno data on economic costs were available. Forexample, we extrapolated the costs associatedwith leafy spurge in the provinces of Alberta andSaskatchewan based upon a study of costs inManitoba and its distribution in each of theseprovinces. In other cases, we calculated costsbased upon reported damage and the value ofindustries aected in areas infested by nuisanceNIS. For example, costs associated with thegreen alga Codium fragile were calculated basedon 10% mortality of oysters, and the value ofthose resources in the area of Prince EdwardIsland where Codium is found. Despite oureorts, characterised costs were a meagre esti-mate of the total economic impact of nuisanceNIS in Canada because only a limited number of</p><p>Figure 1. Examples of externality costs associated with zebra</p><p>mussel invasions. Costs may be direct or indirect (i.e. medi-</p><p>ated through eects on other species or through ecosystem</p><p>changes), and may aect either market (e.g. goods or services)</p><p>or non-market (e.g. ecosystem services, aesthetics) aspects of</p><p>the invaded ecosystem.</p><p>47</p></li><li><p>eects were available for each species, andbecause costs were available only for a smallfraction of all NIS in the country. Moreover, wewere unable to include characterised costs forsome of the most potentially damaging species(e.g. green crab Carcinus maenas, gypsy mothLymantria dispar) owing to a dearth of data.Consequently, a lack of comprehensive, nationaldata for even the most problematic speciesprecludes an accurate assessment of the total eco-nomic impact of nuisance NIS in Canada.In the absence of comprehensive data, empiri-</p><p>cal models can provide a useful approximation ofthe impact of ecological stressors. For example,Ricciardi (2003) utilised a meta-analysis approachto predict the eects of particular NIS. To betterestimate the costs associated with nuisance NIS in</p><p>Canada, we built an empirical model based upon21 quantied eects for previously identied nui-sance NIS from a variety of ecosystems (seeTable 1). For each of these studies, we recordedthe maximum proportional loss in economic valueor experimentally-deduced yield reduction. Weused maximum values because they were oftenthe only values reported. We then ranked theselosses from least to greatest to build an empiricalmodel from which we projected potential lostproduction for a set of identied nuisance NIS inCanada (Figure 2). To keep our projection con-servative, we selected the median case from thiscurve as our maximum cost projection (52%loss), and the quartile (25%) and half-quartile(20%) cases for our medium and low projections,respectively.</p><p>Table 1. Twenty-one quantied eects of 16 NIS of plant, animal and disease. Proportional loss of resource production or value is</p><p>given for each eect, along with references.</p><p>Common name (Scientic name) Impacted resource % Loss Reference</p><p>Clubbed tunicate Shellsh 50 A. Locke, pers. comm.</p><p>(Styela clava)</p><p>Rue Yellow perch, 2560 Leigh 1998</p><p>(Gymnocephalus cernuus) Walleye,</p><p>whitesh</p><p>Leafy spurge Crop yield, 100 Leafy Spurge Stakeholders</p><p>(Euphorbia esula) grazing yield Group 1999</p><p>Spotted knapweed Grazing yield 80 Maddox 1979</p><p>(Centaurea maculosa)</p><p>Horn y Cattle 18 Lysyk et al. 2002</p><p>(Haematobia irritans)</p><p>Seedpod weevil Crop yield 20 Dosdall et al. 2001</p><p>(Ceutorhynchus obstrictus)</p><p>Stable y Cattle, dairy 2040 Bruce and Dekker 1958;</p><p>(Stomoxys calcitrans) Campbell et al. 1987</p><p>Potato late blight Crop yield 52 James et al. 1972</p><p>(Phytophthora infestans)</p><p>Foot and mouth disease Cattle 100 CFIA (2000)</p><p>(Aphthovirus sp.)</p><p>Gypsy moth Tree mortality, 2090 Campbell and Schlarbaum</p><p>(Lymantria dispar) recreation 1994</p><p>Dutch elm disease Tree mortality 30 Hubbes 1999</p><p>(Ophiostoma ulmi)</p><p>Balsam wooly adelgid Tree mortality 80 Hunt 1983</p><p>(Adelges peceae)</p><p>White pine blister rust Tree mortality 94 Hall 1996</p><p>(Cronartium ribicola)</p><p>Schleroderris canker Tree mortality 62 Campbell and Schlarbaum</p><p>(Gremmeniella abietina) 1994</p><p>Beech bark disease Tree mortality 50 Campbell and Schlarbaum</p><p>(Nectria coccinea) 1994</p><p>Asian longhorn beetle Tree mortality 68 Nowak et al. 2001</p><p>(Anoplophora glabripennis)</p><p>48</p></li><li><p>For each of the most problematic invadersselected, we identied the resource(s) placed atgreatest risk (e.g. lobster shery, maple timbersales), and then applied our cost func...</p></li></ul>

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