Enhancing early detection of exotic pests in agricultural and forest ecosystems using an urban‐gradient framework

Abstract

Abstract. Urban areas are hubs of international transport and therefore are major gateways for exotic pests. Applying an urban gradient to analyze this pathway could provide insight into the ecological processes involved in human-mediated invasions. We defined an urban gradient for agricultural and forest ecosystems in the contiguous United States to (1) assess whether ecosystems nearer more urbanized areas were at greater risk of invasion, and (2) apply this knowledge to enhance early detection of exotic pests. We defined the gradient using the tonnage of imported products in adjacent urban areas and their distance to nearby agricultural or forest land. County-level detection reports for 39 exotic agricultural and forest pests of major economic importance were used to characterize invasions along the gradient. We found that counties with more exotic pests were nearer the urban end of the gradient. Assuming that the exotic species we analyzed represent typical invaders, then early detection efforts directed at 21-26% of U.S. agricultural and forest land would likely be able to detect 70% of invaded counties and 90% of the selected species. Applying an urban-gradient framework to current monitoring strategies should enhance early detection efforts of exotic pests, facilitating optimization in allocating resources to areas at greater risk of future invasions.

Exploring associations between international trade and environmental factors with establishment patterns of exotic Scolytinae

“…Although international standards for wood packaging material used in international trade have been adopted since 2002 , individual countries can further reduce the likelihood of establishment and spread of exotic organisms through pest and pathway risk assessments, improved inspection techniques, and early detection survey programs (Brockerhoff et al 2006b;Coulston et al 2008;Rabaglia et al 2008;Brockerhoff 2009;Colunga-Garcia et al 2010;Koch et al 2010). Given the likelihood of increasing international trade it is important that additional research and regulation be considered to reduce the risk of pest invasion through the wood packaging material pathway, which could threaten forest health in Europe and the USA, as well as other countries worldwide.…”

Integrating ecology and genetics to address Acari invasions

“…The threat posed by invasive alien species is far from being well-defined; for example, urban areas are regarded as a gateway for exotic pests (Colunga-Garcia et al 2010), yet their significance for invasions is barely explored. Moreover, the tremendous economic and environmental impact of invasive species is expected to continue with the effect of global change which might favor expanded geographical distribution areas of the species Walther et al 2009;Kriticos 2012;Montserrat et al 2012).…”

Potential establishment of alien-invasive forest insect species in the United States: where and how many?

“…We conducted this estimation at two spatial scales: (a) nationwide and (b) for individual urban areas across the country. Urban forests are not only vulnerable to alien-invasive species, but they also serve as critical gateways for invasions of natural forest ecosystems , 2010bUS Government Accountability Office 2006). Therefore, generating realistic estimates of the potential for human-assisted establishment at such locations should enhance the predictive capability of quantitative models of alien invasion risk such as the one described in Yemshanov et al (2009a).…”