Arrival rate of nonindigenous insect species into the United States through foreign trade

Abstract

Introductions of invasive nonindigenous species, and the ensuing negative ecological and economic consequences, have increased with expanding global trade. Quantifying the influx of nonindigenous plant pest species through foreign trade is required for national and international risk assessments, monitoring and conservation efforts, and evaluation of ecological factors that affect invasion success. Here we use statistically robust data collected at US ports of entry and border crossings to estimate arrival rates of nonindigenous insect species via four cargo pathways and to evaluate the effectiveness of current efforts to monitor arrival of nonindigenous insect species. Interception rates were highest in refrigerated maritime cargo where a new insect species was intercepted on average every 54 inspections. Projected estimates of insect species richness stabilized only for non-refrigerated maritime cargo and US-Mexico border cargo, where inspectors likely detected 19-28% and 30-50% of the species being transported through these respective pathways. Conservative estimates of establishment suggest that 42 insect species may have become established through these four pathways between 1997 and 2001.

Ecological genetics of invasive alien species

“…Routine controls carried out in airports and harbours by quarantine services and monitoring by environmental or agricultural agencies are particularly informative in this respect (Work et al 2005). However, it is rarely possible to infer the routes of invasion with a high degree of precision by these direct methods.…”

Applying a spread model to identify the entry points from which the pine wood nematode, the vector of pine wilt disease, would spread most rapidly across Europe

“…Given the increasing number of alien species introduced to different parts of the world, and their environmental and economic impacts (Pimentel et al 2005;Work et al 2005;Hulme et al 2009a, b;Roques et al 2009), understanding the mechanisms of biological invasions has become an important issue. Approximately 1,300 alien terrestrial invertebrate species are now established in Europe, representing one of the most numerous groups of organisms ).…”

Border control for stowaway alien species should be prioritised based on variations in establishment debt

“…seasonally). These strategies need to be informed by detailed national or regional level studies that consider both the number of organisms likely to be introduced from the donor region (see Bacon et al, 2012;Work et al, 2005) and the climatic similarity of the donor and recipient regions. However, the results of such studies must be carefully interpreted.…”

“…The assumptions made in this model may not hold in all instances and a variety of potentially important factors were not considered. For example, although it has been shown that observed alien species richness increases linearly with an increase in inspection effort (Work et al, 2005), various factors (e.g. packaging type) may affect the ease of inspections and consequently the likelihood of detecting an organism .…”

“…Consequently, only a small proportion of the potential vectors can actually be inspected McCullough et al, 2006) and a large number of organisms go undetected (Stanaway et al, 2001;Work et al, 2005). Inspection services also often only target agricultural pests, neglecting organisms that will have environmental impacts .…”