Natural Heritage Program List of Rare Plant Species - Rawlings ...

What are the main drivers of these changes in the Rare Plant List?
Taxonomic changes. Taxa are added to and deleted from the list based on current understanding of
taxonomy. A small number of taxa have been deleted from the list because they were determined not to
warrant taxonomic recognition (5 taxa), and therefore also not to warrant conservation tracking and action.
An additional 6 taxa have been deleted because the name was misapplied and the taxon was not actually
present in the state by current circumscription, and 5 have been taxa deleted because the specimens upon
which their occurrence in North Carolina was based have been shown to be misidentified. A considerably
larger number of taxa (44) have been added to the Rare Plant List because they are newly recognized as valid
taxa, having "come out of synonymy (44 taxa) or newly described, named, and determined to be rare enough
to be of conservation concern (36 taxa).
Change in knowledge about nativity. Perhaps surprisingly, 13 tracked taxa have been determined not to
be native components of North Carolina's flora. While some of these are native in nearby states and their
nativity status in North Carolina was understandably unclear (Angelica atropurpurea, Hypericum
frondosum), others (Callicarpa dichotoma, Carex divisa, Carex arenaria) are Eurasian taxa. Conioselinum
chinense, a native species in North Carolina and one of the rarest species in the state (now listed as North
Carolina Endangered), was excluded from earlier lists, presumably because Linnaeus's misnomer epithet led
botanists to assume that it was not native.
New information on conservation status resulting from inventory. The existence of the Rare Plant List
and the uses to which it is put generates inventory attention and effort. Once placed on the list, species
receive a considerable amount of focus and effort by biologists conducting conservation assessments, rare
species inventory, county natural area inventory, environmental impact assessments, and (on federal lands)
National Environmental Policy Act assessments. A large number of taxa (103) on the list at some point in
the past have been removed because additional information gathered indicates that they are "secure" at the
present time. An even larger number (152 taxa) has been added to the list because inventory and herbarium
assessments suggest that they warrant conservation attention.
Native taxa newly discovered to be rare components of North Carolina's flora. Continued botanical
exploration and conservation inventory of North Carolina over the last 27 years has revealed a considerable
number of additional taxa (112) to be native and rare components of the state's flora. Once discovered in the
state, these are added to the list.
Actual changes in conservation status. Very few taxa can definitely be shown to have been added to or
deleted from the List because of an actual change in biodiversity status. One of the few is Abies fraseri, a
narrow endemic to the high mountains of the Southern Blue Ridge, which is newly imperiled by the
introduction in the early 1960s and spread of a pathogen, the balsam woolly adelgid. Another ambiguous
case, Tofieldia glabra (a narrow endemic of wet pine savannas and sandhill seeps in the Coastal Plain of the
Carolinas), was removed from the list in part because many of its populations are in secure natural areas.
The addition of mosses, liverworts, hornworts, and lichens to the List. Early lists ignored nonvascular
groups, but these groups of course have their own share of taxa imperiled in North Carolina, and with a
somewhat different geographic pattern across the state, with rare taxa more concentrated in humid, relictual,
western North Carolina than in other parts of the state.
Overall, the level of change in the List and the reasons for that change show a dynamic Rare Plant List which
creates its own feedback loop for continual improvement. Adding taxa to the List generates the attention that
determines the real need (or not) for the taxa to be on the List. Corrections are made over time to reflect new
knowledge about taxonomy, nativity, and conservation status. The importance of conservation inventory and
ongoing taxonomic reassessment is clear.
Do changes in the Rare Plant List make a difference in setting the land conservation agenda?
It would seem likely that changes in the Rare Plant List and associated occurrence records would make a
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