Anthropogenic induced climate change is predicted to alter distribution of existing plant populations. As plants migrate over space and time, populations often fragment and contract, affecting basic elements of population dynamics (e.g., population size, gene flow, genetic diversity, etc.). Little is known, however, how these impacts on plant species will...
Diseases can be a substantial threat to woody plant production, a major industry in Oregon. Boxwood (Buxus spp.) and rhododendron (Rhododendron subgenus Rhododendron and Hymenanthes) represent the top two broadleaf evergreen woody plants by farmgate value in Oregon. Historically, Phytophthora root rot has been considered the most destructive disease of...
Null networks are a type of random graph that is favored for the analysis of a wide variety of real-world networks, including gene-regulatory networks, food webs, and species co-occurrence matrices. As a hypothesis-generating tool, null networks are invaluable because they can reveal network motifs and unusual large-scale properties of networks...
Within the Pacific Northwest, USA, root diseases of conifers are a major forest health concern. These diseases are primarily caused by basidiomycete fungi. These fungal associates play a vital role in carbon sequestration but also have a significant negative economic impact within the timber industry. As a result, research on...
Mosses (Phylum Bryophyta) are widely considered to be among the most ancient groups of land plants (embryophytes) and they are the second most speciose embryophyte phylum with ~13,000 extant species. Despite their diversity and antiquity, mosses have a limited fossil record, which primarily consists of gametophytes entombed in Cenozoic amber....
Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
Plant-pollinator mutualisms are one of the most prevalent and economically important mutualisms in nature. Like many other ecological systems, plant-pollinator communities are threatened by anthropogenic activity, both directly (e.g., habitat conversion and fragmentation) and indirectly (e.g., climate change). While we are aware of many of the activities that adversely impact...
In the mountains of central and southern California, high elevation wilderness areas lack epiphytic lichens that can be used to inform us about atmospheric deposition in multiple ways. Epiphytic lichens are capable of accumulating elements proportionally to the local atmospheric concentration, establishing them as commonly used biomonitor of key elements....
The climate of the Pacific Northwest is in flux, and existing forest ecosystems are stressed and poised to shift in fundamental ways, with or without human intervention. This dissertation probes the nature of forest responses to environmental change through investigations of morphology and genetics of three species of alder co-occurring...
For tuberizing crops like potato (Solanum tuberosum), the geocaulosphere, or the zone of soil in contact with and influenced by the tuber, is a distinct sphere of microbial life and represents an important interface between the potato crop and the soil environment. Upon potato harvest, specific geocaulosphere soil called tare...