Economic impacts of Invasive Alien Species ME408 Maija Kymäläinen Heidi Oranen Jaakko Pesonen
Introduction The number of invaders has been increasing rapidly. Precise economic costs are difficult to estimate. In case of species already extinct losses are impossible to assess. Economic damages associated with non-indigenous species invasions in the United States, the United Kingdom, Australia, India, Brazil and South Africa totals annually more than $336 billion of which control costs account more than $30 billion. This equals $240 dollar cost per capita per year. Estimated losses worldwide total more than $1.4 trillion a year which equals 5 % of the world economy. Even if relatively few of the invasive species become a serious pest, they cause significant damage to ecosystems and cause public health care problems. (Pimentel, D. et al, 2000). Rapid human population growth challenges prevention of further damages. It has been suggested that a few million dollars spent on prevention of potentially harmful alien species from being introduced in the US and other nations would prevent losses of billions of dollars caused to agriculture, forestry and other environments worldwide. (Pimentel, D. et al, 2000). According to DAISIE (2009), there are over 10,600 reported introduced species in Europe, of which about 13% have documented economic impacts. Documented costs which could be identified to economic sectors, are about 6 billion Euros per year, with extrapolated costs of up to 20 billion Euros (Kettunen et al. 2009). General information about the economic losses: New Zealand New Zealand, having the largest number of introduced mammals, second highest number of birds and at least 1800 exotic plant species, ranks as one of the most highly invaded areas on earth. Agriculture, horticulture and forestry are based mainly on introduced species, but ca. 500 introduced plant species threaten these industries and native biodiversity. These species have been naturalizing at a steady state of 12 per year for the last 150 years (Williams & Timmins 2002). The control of animal pests, such as rabbits and stoats, contributes to huge annual costs (Clout 2002). New Zealand economy loses about 400 million NZD a year due to exotic species and about 440 million NZD in preventing increase of these losses. These two costs combined amount to 1% of New Zealand s GDP. Extrapolations with a discount rate of 5-10% make up to an estimate of 9 to 2
19 billion dollars, which represents the value of NZ eradicating all existing pests and ensuring no need for further costs, with the exception of border control (Williams & Timmins 2002). Three different types of economic costs of pests (by Bertram 1999): defensive expenditures, production losses and welfare loss (=the cost of just the existence of pests). In New Zealand around 30 million NZ dollars is spent every year just to control the borders and try to stop any new alien species from arriving there. In 1998-1999 over 15 million NZ dollars was spent on research into possum TB control (brush-tailed possums act as cattle tuberculosis vector). If we look at the production losses caused just by possums, it is estimated that the costs range from 30 million to 60 million NZ dollars per annum (Cowan 1996). Bertram (1996) on the other hand concludes to a mere amount of 36 million NZ dollars worth of production loss caused by minor pests and insects per year. He also tried to estimate the total loss caused by invasive alien species per year in New Zealand. The figure he came up with was 840 million NZ dollars per year, which is 0.9% of the gross national product. Even though the numbers may not be exact, it is undisputed that the amount is still a major drain in the country s economy. The domestic cat (Felis catus) The domestic cat is known to be responsible for the extinction of at least 33 different bird species (Lever 1994). The economic loss of losing a species from our planet is hard to define. In some areas it can affect the whole ecosystem thus making it harder for people to earn their living. The domestic cat is an opportunist and a generalist when it comes to hunting. It kills whatever suitable it comes across (McDonald et al 2007). Therefore the most common prey for cats is the most common species in the hunting area (Liberg 1984). Because being fed by their owners the cat can introduce a unsustainable harvest on their prey species. When introduced to islands cats can do devastating damage to the local endemic species (Tershy et al 2003). Pimentel et al (2005) estimated that the annual cost for losses and damages caused by the domestic cat in the United States was around 17 billion dollars and this does not include the control costs or damage done to any other species than birds. The amount only includes damage done by feral cats (i.e. unknown cats). Urban and pet cats are estimated to have a similar economic effect, although the amount of urban or pet cats is double to ferals. So the total annual cost caused by cats annually for bird populations is estimated to be around 34 billion dollars. 3
The estimated number of cats in Finland is about 500 000 (Turner et al 2000). If we say half of them hunt. And we use the same estimation as for the US cats, then we assume each cat hunts approximately eight birds per year. The estimated price of each adult bird was 30$ according to Pimentel et al (2004). Then we get a number of 60 million dollars worth of economic loss done by domestic cats in Finland every year. Remember this only includes damage done to bird populations. Even though it is not very accurate to calculate the economic loss done by cats in different countries, it gives us some idea of the magnitude of the problem. The American mink (Mustela vison) The American mink was introduced to Finland in the 1920 s as a production animal for fur farms. It was first observed in the wild in the 1930s and it is considered as a threat to native ecosystems (Luonnossa.net). Nowadays it is met almost in the whole country. The mink has also been introduced as a fur animal in other parts of Europe and Russia, and the populations have increased rapidly (IUCN). The mink usually lives near water and swamps and prefers densely vegetated areas. Nests are often dug on river banks, or they can be found under rocks or roots, or in abandoned muskrat holes (IUCN). Minks mate in March and give birth to 2-7 kits in 2-3 months. Minks resemble European minks and polecats, their colour can be from black to almost white and they can be up to 65 cm in length, counting the tail (Metsavastaa). Minks can be found in all of Finland and estimating their total number can prove troublesome. It is hunted yearly because of its harmful effect on small game populations, but most of the 50,000-70,000 annual catch comes from fur animals (Metsavastaa). The mink has a big appetite and a versatile diet. It can eat mammals the size of brown hares, but its main prey are small mammals, frogs, fish, birds and eggs (Metsavastaa). It can be very detrimental to crayfish habitats and bird populations on small islets. Waterfowl litters can suffer greatly because of the mink, which has its effect on the success of duck hunting (Metsästäjäliitto). The American mink is considered as a major reason in the disappearance of European mink from Finland. The populations of European mink have been decreasing in all of Europe after the introduction of American mink. One reason could be that they have very similar ecological niches and American mink is a better competitor (SLL). Exact numbers on the economic losses caused by the mink are hard to find. Minks are notorious in harassing chicken, game and fish farms but most of the damage it causes comes from the impacts on 4
natural ecosystems. Some studies have been made in the UK, where the problems were pinpointed to poultry and fish farms. The raccoon dog (Nyctereutes procynoides) Raccoon dog has arrived from Far East and has adapted to different kinds of climate. To Finland it spread from former Soviet Union where it was introduced during 1935-1953. Raccoon dog breeds effectively partly due to hibernation, opportunistic behavior and omnivory. Its mean brood size in Southern-Finland is 9 whelps. Raccoon dog succeeds in mixed forests, near shores and agricultural lands. (Kauhala, K., 1996, Väänänen, V-M. et al. 2007.) Eradicating raccoon dog is impossible due to litter size increasing with increased hunting pressure (Kauhala, K. & Winter, M. 2009.) Raccoon dogs are harmful to amphibians and game bird populations especially in floodlands and shorelines where they feed on eggs and chicks. As an opportunist it may negatively affect number of broods and reproduction rate of waterbirds (Väänänen, V-M. et al. 2007.) Raccoon dogs carry 32 parasitic worm species, six flea species and it has been speculated that raccoon dog would have brought Asian tick-borne meningoencephalitis virus to Europe. They may carry tuberculosis, anthrax and paratyphoid. (http://www.answers.com/topic/raccoon-dog-1.) Raccoon dog causes economic costs vectoring rabies, fox tapeworm (Echinococcus multilocularis) and trichinellosis. (Kauhala, K. & Winter, M. 2009.) Based on enquiries made to various institutions in Germany it has been suggested that economic damage due to introduction of raccoon dog (and raccoon) has had no impact on small game populations (Gebhardt, H. 1996). In Finland raccoon dog causes insignificant economical losses. Instead, raccoon dogs as fur animals have economic value. However, some damage may occur for example in gardens and strawberry cultivations. Losses are suggested to be similar as those made by birds. (Holmala, K. An e-mail interview 19.4.2010.) 5
References Bertram, G. 1999. The impact of introduced pests on the New Zealand economy, in Pests and Weeds, Hackwell, K. and Bertram, G. Eds., New Zealand Conservation Authority, Wellington, 45 Cowan, PE. 1996. Possum control: prospects for fertility regulation, Reproduction, Fertility and Development 8, 655. Clout, M. N. 2002. Ecological and economic costs of alien vertebrates in New Zealand. Biological invasions. DAISIE. 2009. Handbook of alien species in Europe. Dordrecht, Netherlands:Springer. Gebhardt, Harald. 1996. Ecological and economic consequences of introductions of exotic wildlife (birds and mammals) in Germany. Wildlife Biology, vol. 2, no: 3. September 1996. P. 205 211. Holmala, Katja. Unpublished. An e-mail interview. 19.4.2010. Kauhala, Kaarina. 1996. Supikoira. Riistan jäljille. Toim. Linden, Harto, Heino, Martti & Wikman Marcus. Riista- ja kalatalouden tutkimuslaitos. Edita. Helsinki. Kauhala, Kaarina. & Winter, Marten. 2009. Nyctereutes procynoides (Cray), raccoon dog (Canidae, Mammalia). Handbook of Alien Species in Europe. Invading nature: springer series in invasion ecology 3. Kettunen, M., Genovesi, P., Gollasch, S., Pagad, S., Starfinger, U. ten Brink, P. & Shine, C. 2009. Technical support to EU strategy on invasive species (IAS) - Assessment of the impacts of IAS in Europe and the EU. Lever, C. 1994. Naturalized animals. T & A.D. Poyser Natural History, London. Liberg, O. 1984. Food Habits and Prey Impact by Feral and House-Based Domestic Cats in a Rural Area in Southern Sweden. Journal of Mammalogy, 65(3): 424-432. McDonald, R., Harris, S. & Woods, M. 2003. Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review 33(2): 174. Pimentel, David, McNair, S., Janecka, J., Wightman, J., Simmonds, C., O'Connell, C., Wong, E., Russel, L., Zern, J., Aquino, T. and Tsomondo, T. 2001. Economic and environmental threats of alien plant, animal and microbe invasions. Agriculture, Ecosystems & Environment Volume 84, Issue 1, March 2001, P. 1 20. 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. Putman, R. J. (ed.). 1989. Mammals as pests. The Mammal Society. 271 s. Tershy, B. & Wilcox, B. 2003. Cat eradication significantly decreases shearwater mortality. Animal Conservation 6(4): 307. 6
Turner, D. & Bateson, P. 2000. The domestic cat : the biology of its behaviour. 2nd ed. painos. Cambridge University Press, Cambridge. 244 s s. Väänänen, Veli-Matti, Nummi, Petri, Rautiainen, Antti, Asanti, Timo, Huolman, Ilpo, Mikkola- Roos, Markku, Nurmi, Jarkko, Orava, Reijo & Rusanen, Pekka. 2007. Vieraspeto kosteikoilla vaikuttaako supikoira vesilintujen ja kahlaajien poikueiden määrään? Suomen Riista 53: 49-63. Williams, P.A. & Timmins, S. 2002. Economic impacts of weeds in New Zealand. Biological invasions. http://www.answers.com/topic/raccoon-dog-1 http://www.iucnredlist.org/apps/redlist/details/41661/0 http://www.luonnossa.net/metsastys/minkin_metsastys/minkin_metsastys.html http://www.metsavastaa.net/minkki http://www.metsastajaliitto.fi/?q=node/243 http://www.sll.fi/luontojaymparisto/monimuotoisuus/vieraslajit 7