ACE Irreplaceability (Rank 4 & 5)

ACE Terrestrial Irreplaceability provides a measure of the relative importance of an area based on the number of California endemic, special-status species found there, and the breadth of their distribution, so that species which are more geographically constrained produce a higher score.

This geographic weighting system makes a site more ‘irreplaceable’ because it supports species which are found in fewer locations. Rare endemic species are identified by the California Species of Special Concern reports, the California Rare Plant Rank 1B plants, State or Federally-listed species (threatened, endangered, or candidate species), and fully-protected species. Ranks 4 and 5 are used as an exclusion in the biological planning priorities component of the Core and SB 100 Terrestrial Climate Resilience Study Screens.