Lichen ecology and diversity of a sagebrush steppe in Oregon: 1977 to the present

Authors: MILLER, J.E.D. - Collaborator; Rossman, Amy; ROSENTRETER, R. - US Department Of The Interior; PONZETTI, J. - Collaborator

Submitted to: North American Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2010
Publication Date: 2/11/2011
Citation: Miller, J., Rossman, A.Y., Rosentreter, R., Ponzetti, J. 2011. Lichen ecology and diversity of a sagebrush steppe in Oregon: 1977 to the present. North American Fungi. 6(2):1-14.

Interpretive Summary: Most sagebrush grasslands of western North America are disturbed due to livestock grazing and are susceptible to invasive species such as cheat grass. With efforts to restore grasslands, it is necessary to evaluate the level of disturbance, which can be done by determining the presence or absence of specific lichenized fungi. On one relatively undisturbed grassland preserve in Oregon, the lichens were studied over three decades ago. Recently a lichen survey for the same area was undertaken. In this research the lichens collected previously were compared with those found more recently. It was determined that the lichens that compose the soil crusts are now more numerous, perhaps due to changes in their presence or to increased knowledge about them. This study will be used by land use managers to evaluate the health or disturbance of sagebrush grasslands of western North America.

Technical Abstract: A lichen checklist is presented of 141 species from the Lawrence Memorial Grassland Preserve and nearby lands in Wasco County, Oregon, based on collections made in the 1970s and 1990s. Collections include epiphytic, lignicolous, saxicolous, muscicolous and terricolous species. To evaluate differences between collections made in the 1970s and 1990s, taxa are placed in six morphological groups: crustose, foliose, fruticose, squamulose, stratified nitrogen-fixers and gelatinous nitrogen-fixers. Recent visits to the preserve added a greater proportion of terricolous species to the list than species from other morphological groups, reflecting developments in the taxonomy and understanding of biological soil crusts. The trade-off between smaller-scale study plots that capture accurate species abundance and larger plots that capture more complete species richness is amplified in the sagebrush-steppe because of the small size and cryptic nature of many lichens. We discuss the benefits of both approaches to lichen monitoring in these ecosystems. This project was possible because voucher specimens were saved from the original 1977 survey, which allowed us to address changes in species composition.