Download The role of economics in addressing aquatic invasive species Travis

The role of economics in addressing aquatic invasive species
Travis Warziniack, USFS Rocky Mountain Research Station
Nonnative species are one of the top drivers of ecological change in the United States (Strayer, 2010).
Aquatic plants such as hydrilla, purple loosestrife, and giant salvinia cover entire lakes and alter fish
habitat (Farnsworth and Ellis, 2001; Kelly and Hawes, 2005), dreissena mussels and Asian carp
dramatically alter nutrient levels in water bodies (Strayer, 2009; Bain, 1993; Cudmore and Mandrak,
2004; Pipalova, 2006), and nonnative trout compete through native trout through predation, parasite and
disease transmission, and hybridization (Dunham et al., 2002). Many species also cause extensive damage
to regional economies. Direct damages and control costs from zebra and quagga mussels have reached
$150 million per year in the Great Lakes region and about $1 billion per year throughout the United
States. Damages from sea lamprey have reached $20 million per year, and control costs for purple
loosestrife are $3 million in Florida alone (Pimentel et al. 2005).
Primary means of spread are through transportation vectors and trade in living commodities; slowing
spread must balance gains from trade with threat to the ecosystems and regional economies. Zebra
mussels, for example, were introduced in the Great Lakes region in the late 1980s through ship ballast
water. Water currents carried them downstream, but movement on recreational boats brought them to the
rest of the East. Warziniack et al. (2011) showed that the largest threat of a zebra mussel invasion into the
Columbia River basin would come, not from sources in the East, but from destination sites in the West
like Lake Mead visited by millions of tourists every year. So many boats move between Western
waterways that reducing risk would require reductions in recreational boating large enough to cause
impacts larger than those of an actual invasion (Warziniack et al. 2013).
Integrated models of ecological and economic systems are needed to better assess risk and develop more
efficient policies targeting invasive species (Keller, 2009), demonstrated with a model of an Asian carp
invasion into Lake Erie. Asian carp have colonized the Mississippi River basin and are knocking on the
door of the Great Lakes via artificially created links between the two river basins. Electric barriers have
been erected to keep carp from passing into the Great Lakes, but they may not be effective. Food web
models suggest potential ecological impacts to several species, including a 10-20 percent decline in
walleye. If walleye populations decline, fewer anglers will target walleye. Integrated models with
feedbacks between the economic and ecological systems show actual declines in walleye populations will
be half those predicted by just the food web model.
References:
Bain M.B. (1993) Assessing impacts of introduced aquatic species: grass carp in large systems.
Environmental Management, 17, 211–224.
Cudmore B. & Mandrak N.E. (2004) Biological Synopsis of Grass Carp (Ctenopharyngodon idella).
Canadian Manuscript Report of Fisheries and Aquatic Sciences 2705. Available at
http://sbisrvntweb.uqac.ca/archivage/24061712.pdf.
Farnsworth E.J. & Ellis D.R. (2001) Is purple loosestrife (Lythrum salicaria) an invasive threat to
freshwater wetlands? Conflicting evidence from several ecological metrics. Wetlands, 21, 199–209.
Keller, R. P. (2009). Bioeconomics of invasive species: integrating ecology, economics, policy, and
management. Oxford University Press.
Kelly D.J. & Hawes I. (2005) Effects of invasive macrophytes on littoral zone productivity and food web
dynamics in a New Zealand high-country lake. Journal of the North American Benthological Society, 24,
300–320.
Pimentel, D., Zuniga, R., & Morrison, D. (2005). Update on the environmental and economic costs
associated with alien-invasive species in the United States. Ecological economics, 52(3), 273-288.
Pipalova I. (2006) A review of grass carp use for aquatic weed control and its impact on water bodies.
Journal of Aquatic Plant Management, 44, 1–12.
Strayer D.L. (2009) Twenty years of zebra mussels: lessons from the mollusk that made headlines.
Frontiers in Ecology and the Environment, 7, 135–141.
Strayer, D. L. (2010). Alien species in fresh waters: ecological effects, interactions with other stressors,
and prospects for the future. Freshwater biology, 55(s1), 152-174.
Dunham, J. B., Adams, S. B., Schroeter, R. E., & Novinger, D. C. (2002). Alien invasions in aquatic
ecosystems: toward an understanding of brook trout invasions and potential impacts on inland cutthroat
trout in western North America. Reviews in Fish Biology and Fisheries, 12(4), 373-391.
Warziniack, T., Finnoff, D., Bossenbroek, J., Shogren, J. F., & Lodge, D. (2011). Stepping stones for
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Warziniack, T. W., Finnoff, D., & Shogren, J. F. (2013). Public economics of hitchhiking species and
tourism-based risk to ecosystem services. Resource and Energy Economics, 35(3), 277-294.