Riparian lichens of northern Idaho

Graduation date: 2002Riparian forests in the Idaho Panhandle, north of Whitebird, were surveyed for\ud rare riparian lichen species. The region was stratified into nine geographic units and\ud by stream size. Eighty-one plots were surveyed for lichen community, stand and river\ud characteristics. Variables important to lichen community composition included\ud regional differences, elevation, climatic affinity, floodplain cross-section type, and the\ud amount of basal area in hardwoods. Seventeen species were reported to be rare or\ud uncommon in northern Idaho by lichenologists familiar with eastern Washington,\ud northern Idaho and northwestern Montana. Of the seventeen target species, Cetraria\ud sepincola, Pseudocyphellaria anomala, Ramalina pollinaria and Ramalina\ud subleptocarpha were determined to be rare, with less than 25 occurrences each in\ud northern Idaho. Lobaria hallii, Physconia americana, and Ramalina thrausta were\ud determined to be locally abundant when found, but should continue to be species of\ud concern in northern Idaho because of their limited distribution and narrow habitat\ud requirements. Collema curtisporum is more common in the riparian forests of\ud northern Idaho than previously thought, but appears to be restricted to old Populus\ud balsamfera ssp. trichocarpa (black cottonwood) stands that receive seasonal\ud inundation. Collema occultatum, Nephroma laevigatum, Leptogium cellulosum,\ud Phaeophyscia hirtella, and P. ciliata are all new records for northern Idaho.\ud Management recommendations include maintaining or restoring natural flood cycles\ud in riparian forests and protecting mature black cottonwood stands on floodplains