Canadian Forest Service Publications
Dispersal of invasive forest insects via recreation firewood: a quantitative analysis. 2012. Koch, F.H.; Yemshanov, D.; Magarey, R.D. Smith, W.D. Journal of Economic Entomology 105(2); 438-450.
Available from: Great Lakes Forestry Centre
Catalog ID: 33481
CFS Availability: PDF (request by e-mail)
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Recreational travel is a recognized vector for the spread of invasive species in North America. However, there has been little quantitative analysis of the risks posed by such travel and the associated transport of firewood. In this study, we analyzed the risk of forest insect spread with Þrewood and estimated related dispersal parameters for application in geographically explicit invasion models. Our primary data source was the U.S. National Recreation Reservation Service database, which records camper reservations at 2,500 locations nationwide. For 7 million individual reservations made between 2004 and 2009 (including visits from Canada), we calculated the distance between visitor home address and campground location.We constructed an empirical dispersal kernel (i.e., the probability distribution of the travel distances) from these “origin-destination” data, and then fitted the data with various theoretical distributions. We found the data to be strongly leptokurtic (fat-tailed) and fairly well fit by the unbounded Johnson and lognormal distributions. Most campers(53%) traveled 100 km, but 10% traveled 500 km (and as far as 5,500 km). Additionally, we examined the impact of geographic region, speciÞc destinations (major national parks), and specific origin locations (major cities) on the shape of the dispersal kernel, and found that mixture distributions (i.e., theoretical distribution functions composed of multiple univariate distributions) may fit better in some circumstances. Although only a limited amount of all transported firewood is likely to be infested by forest insects, this still represents a considerable increase in dispersal potential beyond the insects' natural spread capabilities.
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