Scientific Name: Loberia oregana

Description: Loberia oregana is a large-leaf foliose lichen that resembles a piece of lettuce. Its broad lobes (thallus) are 20-35mm wide, frilly on the edges, and textured with a vein like structure made up of depressions and ridges. The upper surface of the lichen is gray-green to yellowish-green; the bottom surface is brown-white to gray-white with patches of fine hair (Pojar and Mackinnon 1994).

Geographical range: Throughout the Pacific Northwest from northern California throughout British Columbia, Canada and Alaska, USA. Mostly restricted to west of the Cascades, except for a small population that resides in south-eastern British Columbia, Canada.

Habitat: This lichen is found on trees in well shaded, cool, and humid forests at low- and mid-elevations. Loberia oregana is incredibly sensitive to light exposure and grows best in a mid-canopy environment. This lichen is primarily restricted to old-growth forests because of its specific light and moisture requirements. Loberia oregana is only found in old-growth forests, and accounts for half of the epiphyte biomass in western Oregon lowland Douglas-fir forests. This lichen is metabolically active when its water content is 70% or higher. Below this level, and during drought times, this lichen ceases to photosynthesize. Thus, it is limited to habitats with moist and cool conditions (Vitt et al 1988).

Reproduction: Lichens reproduce by producing small propagules or by fragmentation. Propagules contain both the algal and fungal cells of the plant and are stored in specialized structures call "soredia". The soredia erupt and propel the cells of algae and fungi througout the forest. If both cells land in an adequate habitat, they begin to lichenize (form a lichen) and grow (Vitt et al 1988). However, most reproduction occurs through fragmentation. Little pieces of lichen, containing both the fungal and algal component, fall off the lichen thallus and establish in the appropriate habitat. Reproduction by fragmentation uses much less energy than reproduction by propagules.

Input requirements (food supply): Lichens are specialized flora that result from a mutualistic symbiotic bond between fungus and algae. The fungal part of the lichen (called the mycobiont) forms the structure of the lichen, giving it shape and a medium for water absorption. It also provides the plants with nutrients absorbed from the substrate. The algal component (called the photobiont), is responsible for providing carbohydrates to the fungus through the process of photosynthesis. In the case of Loberia oregana, which is a nitrogen fixing lichen, little cyanobacteria called Nostoc live on the surface of the lichen. These bacteria change atmospheric nitrogen (N₂), which a plant is not able to consume, to ammonium (NH₄⁺), which the plant can consume. Loberia is only active when temperatures are below 60º and 70% moisture content within the lichen thalli (Kirk and Franklin 1992).

Role in the ecosystem: In a healthy old-growth forest canopy nitrogen-fixing lichens (cyanolichens) are the most dominant epiphytes, where they constitute over half of the total epiphytic mass (Pike et al 1997). Once nitrogen is fixed by the cyanobacteria on the lichen, the nitrogen ultimately ends up on the forest floor via leeching from rain. It is estimated that cyanolichens fix 2.5-4.5 pounds of N per acre of old-growth forest (3-5 kg/ha) per year (Franklin et al. 1981).

Lichens that fall to the forest floor play an important role in supplying deer, elk, and small mammals with winter food.

Use as a Human Resource: This lichen was used by the Hesquit to treat coughs and tuberculosis. Its cousin Loberia pulmonaria was used by early Europeans to treat pneumonia and other lung diseases (Pojar and MacKinnon 1994).

Notes: These cyanolichens are scarce in young forests. The lack of cyanolichens in second-growth forests is possibly due to dispersal limitations, unsuitable substrates and/or unsuitable climate (low moisture/proper light requirements) (Sillet and Neitlich 1996). Researchers have attempted to transplant Loberia oregana into second growth stands, where it rapidly died and decomposed. It is presumed that they did not survive due to the low moisture and higher temperatures found in second growth canopies (Franklin et al. 1981). The presence of Loberia oregana indicates a healthy forest ecosystem with high nitrogen presence.

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