ute to formal rankings of rarity and abundance making them dynamic and subject to continuing input. In the United States, the Heritage Program has established a global rank system that denotes global, regional, and state-specific rarity. The rank of G1, for example, denotes fewer than five occurrences of a given species or community globally; G2 and G3 represents 6–20 occurrences and 21–100 occurrences, respectively; G4 and G5 denotes apparently abundant globally and demonstrably widely abundant species globally, repsectively. The state rankings within the United States are equivalent: S1–S5 parallels G1–G5. Those data are available to the public through NatureServe.org.

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