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

[摘要] We present a lichen checklist 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. One of these collections is the type specimen for a recently described species,Placopyrenium conforme . 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. We determined that recent visits to the preserve added a greater proportion of terricolous species to the list than species from other substrates, reflecting developments in the taxonomy and understanding of biological soil crusts over recent decades. 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 available from the original 1977 survey, which allowed us to address changes in species concepts over recent decades.

[学科分类] 植物学

[关键词] biological soil crusts;Lawrence Memorial Grassland Preserve;lichen floristics;lichen monitoring;Placopyrenium conforme;rangeland health;sagebrush steppe;terricolous lichens