Newly established invasive alien species indicator: data sources and methods, chapter 4


4. Methods

Federal agencies and departments may become aware of new species in Canada through the normal course of business or through searches of public information. Once a new species is identified, government scientists determine whether it is from outside the country, whether it has the potential to cause harm, and whether a population has established.

Data on new invasive alien species and their origin are collected from available sources. New species are assessed to determine whether they should be considered established and their estimated year of establishment. Categories are assigned based on regulatory status: regulated or unregulated species, and regulated or unregulated pathways. It may be impossible to determine by which pathway a species has arrived; in such cases, the pathway is categorized as unknown. The main indicator is a simple count of the number of invasive alien species in each category found to be established in Canada since 2012. Because no new invasive alien species have been found to be established, categories are not yet reported.

In cases where a group of species is regulated as a unit, the unit is treated as a single regulated species for the purposes of the indicator. When a member of a regulated group is established, a new taxonomic unit is created for that species. For example, the import of all species within the genus Helix is prohibited. The European brown garden snail (regulated under the name Helix aspersa) and the Burgundy escargot snail (Helix pomatia) became established in Canada prior to 2011. For the purposes of the indicator, the unit is split and treated as one regulated species that was established before 2012 and one species that is regulated but not established.

Agencies and departments with responsibilities for controlling invasive alien species also conduct risk analysis. One possible outcome of a risk analysis is to regulate particular species or groups of species. Regulations may include, for example, import bans, a requirement for inspection of shipments or veterinary certificates, or transport limitations.

Federally regulated invasive alien species, Canada, 2011 to 2015
Year Alien species regulated and not established
2011 232
2012 234
2013 249
2014 249
2015 254

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