Regularity: Regularly occurring
Global Range: Stylisma pickeringii var. pickeringii has been reported from 19 counties in New Jersey, North Carolina, South Carolina, Georgia, and Alabama, although in recent searches, it has not been relocated in 4 of these counties (Kelly and Weakley 1992). S. pickeringii var. pattersonii occurs in Mississippi, Arkansas, Missouri, Illinois, Iowa, Kansas, Oklahoma, and Texas.
Comments: Stylisma pickeringii occurs primarily in dry pine barrens, pine/scrub oak sandhill, xeric sandhill scrub, and sand-prairies. This species includes two varieties: S. pickeringii var. pickeringii, which occurs primarily on the coastal plain in pine barrens and sandhill communities; and S. pickeringii var. pattersonii, which occurs in sand-prairies and sandy, open ground in the western part of the species range. This species can also occur in somewhat disturbed, sandy soils at roadsides, in clearings, along railroad tracks, and along firebreaks.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 to >300
Comments: A total of 77 extant EOs are known, but the total is likely over 100 because this plant is sufficiently common not to be tracked in Oklahoma and Texas. For Stylisma pickeringii var. pickeringii, 62 extant occurrences are known, from the following states: New Jersey (11), North Carolina (36), South Carolina (7), Georgia (6), and Alabama (2). (Information was gathered from the 1993 EGR for this variety, plus additional records through 1995 for North Carolina and Alabama.). For S. pickeringii var. pattersonii, 15 extant occurrences are known from the following states: Illinois (4 post-1970), Iowa (1 post-1950), Missouri (2), Kansas (3 post-1970), and Arkansas (5). The variety pattersonii is also known from Mississippi, where it is rare, and reported from Oklahoma and Texas, where it is fairly common in sandy, open ground (Poole pers. comm. 1996).
National NatureServe Conservation Status
Rounded National Status Rank: N4 - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: Stylisma pickeringii is somewhat rare across a fairly large portion of its range. A total of 77 extant occurrences of both varieties (var. pickeringii and var. pattersonii) are known, but the actual total of occurrences is likely over 100 because S. pickeringii var. pattersonii is sufficiently common not to be tracked in Texas and Oklahoma. Many occurrences of both varieties are vulnerable to habitat destruction or disruption of the natural fire regime.
Global Short Term Trend: Decline of 10-30%
Comments: Across the range of S. pickeringii var. pickeringii, each state has at least one historical, unrelocated occurrence. For both varieties of S. pickeringii, habitat destruction is occurring across the range.
Comments: The factors affecting the continued existence of the species as identified in the Status Survey (Kelly and Weakley 1992) are as follows: (1) The present or threatened destruction, modification, or curtailment of its habitat or range, mostly through commercial and residential development, paved road and foodplot construction, trampling by ORVs and military vehicles, trash dumping, and fire suppression. (2) The inadequacy of existing regulatory mechanisms.
Only North Carolina and Georgia have laws protecting Stylisma from taking. Only North Carolina provides for management, and only New Jersey protects its habitat. After habitat destruction, disruption of the natural fire regime is probably the greatest threat to Stylisma pickeringii occurring in intact, upland habitats. Historically, frequent fires probably maintained large areas suitable for Stylisma pickeringii var. pickeringii; removal of this disturbance from the landscape over the past century, as well as altering its timing, frequency, and intensity have probably reduced large numbers of plants.
Occurrences along the Pee Dee River and Little River terraces may also be threatened by natural or human-related alterations in the flood cycles of these waterways. Although roadside and parachute drop zone populations appear to be thriving in the presence of some level of ground disturbance, they are always under the constant threat of catastrophic disturbance. Roadbed widening or heavy equipment activity on the drop zones, for example, may dramatically reduce the number of individuals in an occurrence. These reductions, if they come at a crucial stage in the species' reproductive cycle (i.e., during flower or fruit production), could have severe long-term effects on the population. Although it appears that this species can rebound from large disturbances, it is not clear how much seed bank and genetic diversity is lost from each disturbance.
Biological Research Needs: A top priority research need is to determine Stylisma's habitat requirements, including the importance of fire (seasonal timing, intensity, and frequency) and disturbance (mechanical) on plant health and reproduction. There is also a need to determine under what conditions Stylisma pickeringii germinates, especially in natural and semi-natural plant communities and to answer specific questions regarding pollination ecology, genetic impoverishment, and genetic and ecological distinctiveness among populations throughout its range. Other studies should focus on what environmental factors other than fire exclusion may contribute to the limited distribution of the species (such as seed predation and fungal infection) (Prince 1992). Stylisma pickeringii's ability to colonize xeric disturbed areas such as the Fort Bragg drop zones and sandy roadsides makes it perhaps a valuable soil stabilization species. Researchers with the Soil Conservation Service may be interested in experimenting with this species, especially for the numerous erosion control projects on Fort Bragg. Propagators at the North Carolina Botanical Garden in Chapel Hill, North Carolina, are studying germination requirements for the species in both greenhouse and in situ test areas. No other research activities are known for the species.
Names and Taxonomy
Comments: USFWS formerly (2/90) tracked the candidate species as Stylisma pickeringii var. pickeringii, but now considers the full species as candidate 2 (9/93).
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