LICHEN COMMUNITIES ON ULTRAMAFIC AND GRANITIC SUBSTRATES - A COMPARISON IN THE CENTRAL SAVANNAH RIVER AREA, EASTERN PIEDMONT, GEORGIA AND SOUTH CAROLINA

Recent studies find greater diversity of lichens on ultramafic rock types of the Burks Mountain Complex (BMC) as compared to nearby communities developed on various granitic rock types. The serpentinized BMC produces magnesium-rich soils which are known to retard and/or inhibit the growth of many plant species. The BMC outcrops produce a savannah-like environment characterized by dwarf blackjack oak, short and longleafed pines, and grassy open areas. In addition, our research finds a greater diversity of lichen communities on BMC rocks.

The BMC ultramafic rocks are located south of Thurmond Lake in western South Carolina and eastern Georgia. The BMC mineralogy consists of serpentine group minerals, chromite, magnetite, talc, tremolite, and carbonate.

Comparison of lichen communities by form and coloration show six types on BMC outcrops, and three types on granitic rocks. Foliose(gray-blue, sea-green, brown), crustose(golden-yellow), squamulose(light sea-green), and fruticose(gray-red) lichen forms are all present on BMC substrates. Only foliose (sea-green, gray-blue) and crustose(sea-green) forms are found on the granitic outcrops.

Lichens inhabit environments of little competition which allow them to be successful even in extreme environments such as the rocks of the Burks Mountain complex.