Global threat to agriculture from invasive species
- aCommonwealth Scientific and Industrial Research Organization, Canberra, ACT 2601, Australia;
- bPlant Biosecurity Cooperative Research Centre, Bruce, ACT 2617, Australia;
- cDepartment of Agriculture and Food, Western Australia, Bunbury, WA 6230, Australia;
- dSchool of Agricultural and Resource Economics, The University of Western Australia, Crawley, WA 6009, Australia;
- eCommonwealth Scientific and Industrial Research Organization, Brisbane, QLD 4001, Australia;
- fBio-Protection Research Centre, Lincoln University, Lincoln 7647, New Zealand;
- gDepartment of Entomology, Penn State University, State College, PA 16802;
- hCenter for Infectious Disease Dynamics, Penn State University, State College, PA 16802
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Edited by Harold A. Mooney, Stanford University, Stanford, CA, and approved April 28, 2016 (received for review February 13, 2016)

Significance
A key scientific and policy challenge relating to invasive species at the world level is to understand and predict which countries are most vulnerable to the threat of invasive species. We present an analysis of the threat from almost 1,300 agricultural invasive species to the world (124 countries). The analysis examines the global distribution of these species, international trade flows, and each country’s main agricultural production crops, to determine potential invasion and impact of these invasive species. We found the most vulnerable countries to be from Sub-Saharan Africa, while those countries representing the greatest threat to the rest of the world (given the invasive species they already contain, and their trade patterns) to be the United States and China.
Abstract
Invasive species present significant threats to global agriculture, although how the magnitude and distribution of the threats vary between countries and regions remains unclear. Here, we present an analysis of almost 1,300 known invasive insect pests and pathogens, calculating the total potential cost of these species invading each of 124 countries of the world, as well as determining which countries present the greatest threat to the rest of the world given their trading partners and incumbent pool of invasive species. We find that countries vary in terms of potential threat from invasive species and also their role as potential sources, with apparently similar countries sometimes varying markedly depending on specifics of agricultural commodities and trade patterns. Overall, the biggest agricultural producers (China and the United States) could experience the greatest absolute cost from further species invasions. However, developing countries, in particular, Sub-Saharan African countries, appear most vulnerable in relative terms. Furthermore, China and the United States represent the greatest potential sources of invasive species for the rest of the world. The analysis reveals considerable scope for ongoing redistribution of known invasive pests and highlights the need for international cooperation to slow their spread.
Footnotes
- ↵1To whom correspondence should be addressed. Email: Dean.Paini{at}csiro.au.
Author contributions: D.R.P., A.W.S., D.C.C., P.J.D.B., S.P.W., and M.B.T. designed research; D.R.P. performed research; D.R.P. and D.C.C. contributed new reagents/analytic tools; D.R.P. analyzed data; and D.R.P., A.W.S., D.C.C., P.J.D.B., S.P.W., and M.B.T. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1602205113/-/DCSupplemental.
Freely available online through the PNAS open access option.