Definition: A taxon is Extinct when there is no reasonable doubt that the last individual has died. A
taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat,
at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed
to record an individual. Surveys should be over a time frame appropriate to the taxon’s
life cycle and life form.
Definition: Treeless, level, or gently rolling plains characteristic of arctic or subarctic regions, having a permanently frozen subsoil, and usually supporting low growing vegetation such as lichens, mosses, and stunted shrubs.