Lepraria lanata

Lepraria lanata is a crustose lichen occurring on rock overhangs, outcrops, wet walls, soil, hummus, and organic matter in high-elevation spruce-fir forests of the southern Appalachian Mountains region of Georgia, North Carolina, and Tennessee. There are an estimated 18 occurrences of this species, the majority of which are located in the Great Smoky Mountains National Park or on National Forest lands. This species is restricted to mature spruce-fir forests, which have been heavily impacted by logging throughout the 20th century and by the exotic balsam woolly adelgid, which has led to significant mortality of mature Fraser fir stands. Climate change is also projected to reduce cloud immersion in this region and to drastically reduce available suitable habitat for Lepraria lanata, and populations should be monitored closely for declines.

Lepraria lanata is endemic to the eastern United States, where it occurs in high elevations of the southern Appalachian Mountains of Georgia, North Carolina, and Tennessee (Allen et al. 2020). Specifically, it is known from the Great Smoky Mountains, the Black Mountains, Rabun Bald, and Roan Mountain. Range extent was estimated using herbarium specimens collected between 1993 and 2024 (Consortium of Lichen Herbaria 2024, GBIF 2024).

By applying a 1 km separation distance to herbarium records documented between 1993 and 2024, it is estimated that there are 18 occurrences rangewide (Consortium of Lichen Herbaria 2024, GBIF 2024). The majority of occurrences were documented since 2005 and are considered to be extant (Allen et al. 2020). Extensive field surveys for this species occurred on nearly all the high elevation ridges of the Great Smoky, Balsam, Black, and Roan Mountains of North Carolina in 2014, which located several new populations (Allen and Lendemer 2016).

Historical threats to Lepraria lanata included intensive logging throughout the 20th century, which likely led to the extirpation of many individuals (see long-term trends). Climate change is a significant concern for this high-elevation lichen, especially at sites on the lower elevation range of the species, which will likely become hotter and drier (Allen and Lendemer 2016). Lepraria lanata is predicted to lose between 70 to 100 percent of its current distribution by 2050 and 2070 under various climate change models. In addition, frequent cloud immersion at high elevations is predicted to decrease with climate change, which could cause impacts to species adapted to cool, moist conditions maintained by fog (Culatta and Horton 2014). Another significant threat to high-elevation spruce forests where this species occurs is an invasive tree pest from Europe, the balsam woolly adelgid (Adelges piceae) (Onken and Reardon 2005). This species was first introduced into the northeastern United States in the late 1900s, and by the 1980s, it had caused 91 percent mortality of mature Fraser fir trees in the Great Smoky Mountains National Park region. Thus habitat loss as a result of the loss of mature fir stands to predation represents a significant threat to Lepraria lanata (Allen et al. 2020).