Negative and Eradicated Records - Why?

🤔 Question

Why are there records where a species was not found?

🌱 Answer

There are two statuses in EDDMapS for documenting a species being absent

Negative Records - Species was looked for and was not found
Eradicated Records - Species was present, but has been looked for and hasn’t been found for long enough to be considered locally extinct.

Absence records (Negative and Eradicated records) for a species can be informative for a few reasons:

1. Allow for survey efforts to be documented

   1. Negative and Eradicated records show the species has been looked for and not found, compared to a lack of data where the status of presence cannot be determined

2. Allow for knowing more precisely when a new population moved in

   1. Years of surveying at a location for a species followed by a positive sighting provides a possible timeline for when the species likely established

3. Eradicated records allows for the past presence of the species existing in a location

   1. This lets people know that the location is a possible site for re-infestion later due to previous establishment

Many invasive plant species on EDDMapS have modeling data on their Distribution Maps county page to show research done on where these species are likely to occur in the future: Future Range, Future Certainty, Future Habitat Abundance.

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