Nonindigenous species introductions: a threat to Canada's forests and forest economy.
When organisms are moved from their natural range to new ecosystems, they are considered nonindigenous, invasive or exotic species. Movement of exotic or native species may be international or from areas within Canada. Historically, Canada's forests have felt the effects of nonindigenous species introductions, as for example, Dutch elm disease (Ophiostoma ulmi), white pine blister rust (Cronartium ribicola), gypsy moth (Lymantria dispar) and pine shoot beetle (Tomicus piniperda). With changes in global trade patterns, novel introductions will continue to occur. Although most of the research and regulatory efforts to control the movement of nonindigenous species has focused on insects, projects are underway to study fungal organisms and their association with insect vectors. International quarantine standards are being developed to minimize the risk associated with solid wood packing materials, a major entry pathway for nonindigenous organisms. Research needs include the development of enhanced detection capabilities, improved diagnostic tools, effective mitigation measures, as well as socio-economic impact assessments and basic biological information about nonindigenous species and their interactions with hosts.