We sampled vegetation, bryophytes, lichens, environment, and stand dynamics in 56 plots in the Swan Valley, Montana in 1975-1978. The data include complete inventory of trees in 375 m2 plots, with whole-plot ocular estimates of plant cover by species, transect sampling of the ground layer bryophytes and lichens with microplots,...
Mountain environments are currently among the ecosystems least invaded by non-native species; however, mountains are increasingly under threat of non-native plant invasion. The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental gradients. The...
Nitrogen-fixing lichens (cyanolichens) are an important source of nitrogen (N) in Pacific Northwest forests, but limitation of lichen growth by elements essential for N fixation is poorly understood. To investigate how nutrient limitation may affect cyanolichen growth rates, we fertilized a tripartite cyanobacterial lichen (Lobaria pulmonaria) and a green algal...
Introduction: Biotic soil crust communities contribute valuable ecosystem services and biodiversity in steppe ecosystems. The uncommon crust lichens Acarospora schleicheri, Fuscopannaria cyanolepra, Rhizocarpon diploschistidina, and Texosporium sancti-jacobi are associated with fine-textured soils along rivers of the Columbia Basin. A. schleicheri and R. diploschistidina indicate late-successional habitat and may serve as...
Hypogymnia imshaugii is one of the most common, conspicuous and morphologically variable epiphytic lichens of the Pacific coastal states and provinces. The species varies greatly in morphology and chemistry, suggesting multiple closely related species or one or more phenotypically plastic species. We sought to determine whether additional ecologically meaningful species...
Questions: Can a statistical model be designed to represent more directly the nature of organismal response to multiple interacting factors? Can multiplicative ernel smoothers be used for this purpose? What advantages does this approach have over more traditional habitat modelling methods?
Methods: Non-parametric multiplicative regression (NPMR)was developed from the premises...
The epiphytic lichen Letharia vulpina has been commonly sampled in-situ for nitrogen (N) deposition biomonitoring studies but has never before been transplanted for this purpose. In the high-elevation wilderness areas of southern California Letharia vulpina is generally uncommon, making in-situ sampling difficult. In this study, we compared thallus N accumulation...
Spatial variation of available food resources can be difficult to accurately quantify for wide ranging organisms
at landscape scales. Lichens with usnic acid, a yellowish pigment, constitute a large portion of caribou winter
diet across much of their range. We take a new approach of modeling lichen abundances by capitalizing...