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Vascular plant extinction in the continental United States and Canada
Author(s) -
Knapp Wesley M.,
Frances Anne,
Noss Reed,
Naczi Robert F. C.,
Weakley Alan,
Gann George D.,
Baldwin Bruce G.,
Miller James,
McIntyre Patrick,
Mishler Brent D.,
Moore Gerry,
Olmstead Richard G.,
Strong Anna,
Kennedy Kathryn,
Heidel Bonnie,
Gluesenkamp Daniel
Publication year - 2021
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1111/cobi.13621
Subject(s) - extinction (optical mineralogy) , vascular plant , geography , biodiversity , iucn red list , taxon , ecology , endemism , local extinction , biology , species richness , demography , paleontology , population , biological dispersal , sociology
Extinction rates are expected to increase during the Anthropocene. Current extinction rates of plants and many animals remain unknown. We quantified extinctions among the vascular flora of the continental United States and Canada since European settlement. We compiled data on apparently extinct species by querying plant conservation databases, searching the literature, and vetting the resulting list with botanical experts. Because taxonomic opinion varies widely, we developed an index of taxonomic uncertainty (ITU). The ITU ranges from A to F, with A indicating unanimous taxonomic recognition and F indicating taxonomic recognition by only a single author. The ITU allowed us to rigorously evaluate extinction rates. Our data suggest that 51 species and 14 infraspecific taxa, representing 33 families and 49 genera of vascular plants, have become extinct in our study area since European settlement. Seven of these taxa exist in cultivation but are extinct in the wild. Most extinctions occurred in the west, but this outcome may reflect the timing of botanical exploration relative to settlement. Sixty‐four percent of extinct plants were single‐site endemics, and many occurred outside recognized biodiversity hotspots. Given the paucity of plant surveys in many areas, particularly prior to European settlement, the actual extinction rate of vascular plants is undoubtedly much higher than indicated here.