Thelomma carolinianum is a very rare species, endemic to the Coastal Plain of the southeastern United States. The species is known almost entirely from historical records (<1930), only a small number of modern records (>
2000), and appears to have been extirpated from most of its range, which is an area that has been, and continues to be, highly altered centuries of land use.
Thelomma carolinianum is narrowly endemic to the Coastal Plain of southeastern North America.
The species is known from less than three dozen collections, the majority from <1930, several from 1930-1990, and only small number from modern times. Intensive field study by multiple lichenologists throughout the historical range of the species has failed to relocate most historical populations and these are presumed extirpated. Considering the above, we consider the populations to have been in decline for a protected time period and “deteriorating” at present.
Population Trend: Decreasing
Based on the historical records and limited modern observations, the species appears to be restricted to the hardened wood and lignum of conifers in low-lying coastal swamps.
In addition to intense pressure from development and other forces (industry, urbanization), much of the remaining habitat in the region where this species occurs is imperiled by sea-level rise. Additional threats include pollution, road expansion and maintenance, logging and other threats that would further degrade the remaining habitats where the species occurs or could potentially occur.
Further research that will aid in the conservation of this species includes population assessments and monitoring, population genetics studies, and ecological studies that incorporate threats to the species. Additionally, a species recovery plan needs to be written.
Tibell, L 1976: The genus Thelomma. - Bot. Not. 129: 221-249.