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The Atlantic CDC maintains comprehensive lists of plant and animal species, with a rarity rank and legal status for each.  These lists, the result of collaboration with regional experts, aid the development of sub-national rarity ranks (S-ranks).  To date, the Atlantic CDC has compiled S-ranks for most vascular plant and vertebrate animal species and for some non-vascular plant and invertebrate species.

Although continually increasing, the Atlantic CDC presently has over 40,000 records of extremely rare to uncommon species in the Atlantic region, with over 8,000 for New Brunswick, 6,000 for Nova Scotia, 2,000 for Prince Edward Island, 6,500 for Newfoundland, and 60 for Labrador.

The Atlantic CDC also maintains biological and other types of data (information sources, professional contacts, data requests, etc.)  in a variety of linked databases.  For information about these, please contact our Data Managers, Stefen Gerriets in the Maritimes, or Meherzad Romer in Newfoundland & Labrador.

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Element Occurences

The Atlantic CDC develops species location data, known as element occurrence records.  Occurrence precision (“accuracy”) ranges from quite precise (within meters) to less precise (within counties) but most commonly it is within 1 – 5 km.  Element occurrence (EO) refers to one or more locations considered important to the continued existence of a species or ecological community. 

For species, over 30 types of data: taxonomy, biology, etc. are typically examined when identifying EOs.  An EO is generally the habitat occupied by a local population.   However, occurrence varies among species and some species have more than one type of occurrence (e.g., breeding and winter occurrences).   Breeding colonies, breeding ponds, denning sites, and hibernacula are general examples of different types of animal EOs.   For an ecological community, an EO may be the area containing a patch of that community type.

An EOR is an electronic Element Occurrence Record of all the information about each EO type (e.g., breeding colony), geo-referenced data, data related to the observation or collection, name(s) of the observer or collector, habitat information, number of individuals, etc.

To generate EORs, CDC biologists and other experts examine observation records and determine how they should be aggregated.   For example, records over several years of a single active Peregrine Falcon nest would be aggregated into a single element occurrence for that species.   Whenever possible, staff specialists rely on element occurrence specifications developed by NatureServe and the international CDC/NHP (Natural Heritage Program) network to guide the development of EORs.  

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The relationship between species observational records (points) and EORs.