Lobaria scrobiculata (Scop.) DC. in Lam. & DC.
Basis for Listing
Lobaria scrobiculata has a primarily northern distribution in North America with occurrences in Canada, the Lake Superior region, the northern coasts of the eastern and western United States, and Colorado. It is never abundant anywhere within its range. This lichen was collected three times between 1897 and 1902 in Cook County, but it has been found in only one locality in the last 30 years. The extensive decrease in moist, mature forest habitat in northern Minnesota has threatened this species with elimination from the state. For this reason, L. scrobiculata was listed as an endangered species in Minnesota in 1984.
Lobaria scrobiculata is a foliose (leaflike) lichen. The grayish-brown thallus (lichen body) has spots of soredia (powdery granules containing both algal and fungal components) on the upper surface and margins. Lobe tips are rounded and the upper surface of the thallus is weakly ridged to undulating. The lower surface has light-colored bare spots and brown tomentum (thin hairs).
This species grows on trees and mossy rocks in moist areas, on cliffs at the margins of swamps, and near the shore of Lake Superior in undisturbed conifer forests. It is most often found on shady, north-facing cliffs near the lakes. In other parts of its range, it frequently occurs on trees. The Minnesota collections of L. scrobiculata have been from mossy rocks and from Thuja occidentalis (northern white cedar) trees.
Biology / Life History
Lobaria scrobiculata reproduces asexually, depending on dispersal of soredia. Soredia can be dispersed by wind, water, animal, or insect. If the soredia are deposited in a favorable habitat, a new lichen thallus can grow from the soredia. In Europe, this lichen has been used as a brown dye for wool (Uphof 1959).
Conservation / Management
Loss of habitat is the primary threat to this species. The most prominent agents of habitat alteration or destruction include housing developments, recreational use, and environmental changes such as climate change. Any alterations that disrupt the humidity of L. scrobiculata's environment would likely have a negative effect on populations of this lichen. It is also believed to be sensitive to sulfur dioxide pollution.
Conservation Efforts in Minnesota
This species and other rare lichens are targeted for botanical searches by scientists in an attempt to locate additional occurrences and conserve remaining populations.