State and Global Rarity Ranks

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State Rarity Ranks

State Rarity Ranks are determined by the Maine Natural Areas Program.

  • S1 Critically imperiled in Maine because of extreme rarity (five or fewer occurrences or very few remaining individuals or acres) or because some aspect of its biology makes it especially vulnerable to extirpation from the State of Maine.
  • S2 Imperiled in Maine because of rarity (6-20 occurrences or few remaining individuals or acres) or because of other factors making it vulnerable to further decline.
  • S3 Rare in Maine (20-100 occurrences).
  • S4 Apparently secure in Maine.
  • S5 Demonstrably secure in Maine.
  • SH Known historically from the state, not verified in the past 20 years.
  • SX Apparently extirpated from the state, loss of last known occurrence has been documented.
  • SU Under consideration for assigning rarity status; more information needed on threats or distribution.
  • S#? Current occurrence data suggests assigned rank, but lack of survey effort along with amount of potential habitat create uncertainty (e.g. S3?).

Global Rarity Ranks

Global Ranks are determined by NatureServe.

  • G1 Critically imperiled globally because of extreme rarity (five or fewer occurrences or very few remaining individuals or acres) or because some aspect of its biology makes it especially vulnerable to extinction.
  • G2 Globally imperiled because of rarity (6-20 occurrences or few remaining individuals or acres) or because of other factors making it vulnerable to further decline.
  • G3 Globally rare (20-100 occurrences).
  • G4 Apparently secure globally.
  • G5 Demonstrably secure globally.
  • GNR Not yet ranked.

State Legal Status

State legal status is defined according to Title 12 Section 544, and Title 12 Section 544 B which mandate the Department of Agriculture, Conservation and Forestry to produce and biennially update the official list of Maine's Endangered and Threatened plants. Periodic changes to the list are recommended to the Department by a technical advisory committee of botanists who use the most recent population data as per the Maine Natural Area Program's database, along with other relevant research and taxonomic information to recommend status changes.

  • E ENDANGERED; Rare and in danger of being lost from the state in the foreseeable future; or federally listed as Endangered.
  • T THREATENED; Rare and, with further decline, could become endangered; or federally listed as Threatened.

Non-Legal status

  • SC SPECIAL CONCERN; Rare in Maine, based on available information, but not sufficiently rare to be considered Threatened or Endangered.
  • PE Potentially Extirpated; Species has not been documented in Maine in past 20 years or loss of last known occurrence has been documented.