Biological Rarity Index
The Biological Rarity (Biorarity) Index model is based on the Michigan Natural Features Inventory database of known occurrences of threatened, endangered, or special concern species and high-quality natural communities. Each record was spatially subset to its habitat using landcover data, stream lines, and rail corridors. The record was then assigned three values based on the species' Global status, State status, and occurrence quality rank. These values are multiplied by a probability of continued occurrence factor based on the age of the database record. Finally, the scores of all the records in a geographic unit are summed to determine the Biorarity Index for that unit. In this map, two layers are presented: an overview layer 'Cogs', and a more detailed layer, 'Hexagons'. Both layers present the Biorarity Index and Probability of Occurrence for the data represented in each geographical unit.
Model last updated: June 2024