Botany Commons^™

Rare, Threatened And Endangered Species Of Oregon (2019), Jimmy Kagan, Sue Vrilakas, Eleanor P. Gaines, Lindsey K. Wise, Michael Russell, Cayla Sigrah

Institute for Natural Resources Publications

The Oregon Biodiversity Information Center (ORBIC) is part of the Institute for Natural Resources (INR) located at Portland State University (PSU). ORBIC maintains extensive databases of Oregon biodiversity, concentrating on rare and endangered plants, animals and ecosystems. Since its creation in 1979 as the Oregon Natural Heritage Program, ORBIC has been part of the Natural Heritage network. ORBIC is a constituent member of NatureServe, a non-profit organization with a mission to provide the scientific basis for effective conservation action. NatureServe and Oregon manage data using standards and protocols used across the U.S., Canada, and much of Latin America.

ORBIC has …

Composition And Dispersal Dynamics Of Vegetation Communities In Urban Riparian Forests, Christa Von Behren

Dissertations and Theses

In urban riparian areas, vegetation composition may be affected by urban land use changes at both the stream reach and the watershed scale. Moreover, the mechanisms by which seeds disperse may be affected both by reduction in seed sources due to vegetation removal and by the urban stream syndrome that produces flashier hydrographs and incised channels. I hypothesized that vegetation communities with high cover of native and hydrophilic species would be found in watersheds with high forest cover, while more limited cover of these species would be found in highly developed watersheds. Additionally, to examine the dispersal mechanisms contributing to …

Response Of Sagebrush Steppe Species To Elevated Co2 And Soil Temperature, Melissa S. Lucash, Blake Farnsworth, William E. Winner

Environmental Science and Management Faculty Publications and Presentations

Elevated atmospheric CO₂ may cause long-term changes in the productivity and species composition of the sagebrush steppe. Few studies, however, have evaluated the effects of increased CO₂ on growth and physiology of species important to this ecosystem. Since the response of plants to elevated CO₂ may be limited by environmental factors, soil temperature was also examined to determine if low soil temperatures limit CO₂ response. To determine how CO₂ and soil temperature affect the growth of species native to the sagebrush steppe, bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey], Thurber needlegrass (Stipa thurberiana Piper), …

Relationships Between Needle Nitrogen Concentration And Photosynthetic Responses Of Douglas-Fir Seedlings To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

• Here we examined correlations between needle nitrogen concentration ([N]) and photosynthetic responses of Douglas-fir (Pseudotsuga menziesii) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO₂]).
• Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient+3.5^° C and ambient or ambient +180 μmol mol^-1 CO₂ in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.
• Needle [N] varied seasonally, and accounted for 30–50% of the variation in photosynthetic parameters. Across measurement periods, elevated temperature increased needle [N] by 26% and light-saturated …

Stomatal Responses Of Douglas-Fir Seedlings To Elevated Carbon Dioxide And Temperature During The Third And Fourth Years Of Exposure, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

Two major components of climate change, increasing atmospheric [CO₂] and increasing temperature, may substantially alter the effects of water availability to plants through effects on the rate of water loss from leaves. We examined the interactive effects of elevated [CO₂] and temperature on seasonal patterns of stomatal conductance (g_s), transpiration (E) and instantaneous transpiration efficiency (ITE) in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings. Seedlings were grown in sunlit chambers at either ambient CO₂ (AC) or ambient + 180 µmol mol^-1 CO₂ (EC), and at ambient temperature (AT) or ambient + 3.5° …

Rare, Threatened And Endangered Vascular Plants In Oregon: An Interim Report, Jean L. Siddall, Kenton L. Chambers, David H. Wagner

Institute for Natural Resources Publications

This report on rare, threatened and endangered vascular plants in Oregon is a basic document in the process of inventorying the state's natural areas * Prerequisite to the orderly establishment of natural preserves for research and conservation in Oregon are (1) a classification of the ecological types, and (2) a listing of the special organisms, which should be represented in a comprehensive system of designated natural areas. The necessary ecological classification was published in the U.S. Forest Service Pacific Northwest Forest and Range Experiment Station document, "Research Natural Area Needs in the Pacific Northwest," by Dyrness et al. (1975). This …