Global Compendium of Weeds:
reference terms

Status

• Weed: The reference source was not specific but in most cases these are economic weeds (i.e., agriculture, horticulture, turf, nurseries, etc.). The source details can usually give some idea of the type of weed, but is not conclusive in all cases.
  
  
• Sleeper weed: Species that have been identified as present and posing a future threat. Often the source of these references has already been proved correct by other publications acknowledging the species impacts.
  
  
• Quarantine weed: Species prohibited entry under a country's quarantine regulations. (See also noxious weed for distinction/possible status overlap.)
  
  
• Noxious weed: Species subject to legal restrictions (i.e., control, eradication, containment, etc.); for some countries this term also encompasses quarantine species (i.e., U.S. Federal Noxious Weeds).
  
  
• Naturalised (aka naturalized): Species has self-sustaining and spreading populations with no human assistance, but not necessarily impacting the environment. A species' capacity to naturalise in foreign environments, however, is a good indicator of weed potential.
  
  
• Native weed: Species that are native to the country they are considered weedy. Sometimes difficult to determine if the species has spread outside its native range within its country of origin or is weedy within its native range, as sources are often state- or regionally-based.
  
  
• Introduced: Species that have been released (planted) that may or may not have become naturalised. A term that is often used as an alternative to "naturalised"; sometimes very difficult to determine which term is appropriate. Introduced taxa obviously include many species deemed desirable by humans for one purpose or another, and many weeds enter countries via this pathway. Forestry, agriculture, and horticulture are traditionally the biggest advocates of species introduction programs. Lately, overseas aid agencies have become involved in regeneration projects and--rather than use native species--often introduce exotic species with little regard to their future weed potential.
  
  
• Garden escape: Garden species known to have escaped either directly by seed or other propagules moving out of the garden or indirectly by establishing from dumped garden waste. Other garden escapes originate from abandoned gardens, graveyards, and commercial tips, to name just a few.
  
  
• Exotic: Rarely used here, but denotes where a species is know to be present but its exact status is unknown.
  
  
• Environmental weed: Species that invade native ecosystems. Many of these can be easily determined from the source references. In the past, most attention has focused on agronomic weeds. This data set provides information on over 2,000 environmental weed species.
  
  
• Cultivation escape: Species may have escaped from gardens, cultivation, or both; source not specific, but includes some crop and pasture species.
  
  
• Casual alien: These species appear with no direct (apparent) human assistance, survive, possibly set seed, but do not persist, then may appear again some seasons later (i.e., they do not develop long-term sustained populations).
  

If you have corrections to the GCW, can recommend additional source documents for the GCW, or require further information about the GCW, please contact gcw@hear.org.

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