Thesis
Silene spaldingii (Spalding's catchfly) population vigor and community characteristics in Asotin County, Southeastern Washington
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/103553
Abstract
Silene spaldingii (Spalding’s catchfly) is a perennial forb, endemic to the inland Pacific Northwest and listed as threatened by the U.S. Fish and Wildlife Service. The plant inhabits landscapes subject to historical land-use change and degradation, including bunchgrass, sagebrush-steppe, and ponderosa pine communities. In a recently discovered population in southeastern Washington bunchgrass habitat, we compared sites that contained Silene spaldingii to sites without the plant to determine its growth within suitable habitats on northerly aspects. Silene spaldingii was found between aspects of 285 – 75 °, on slopes up to 45 °, and was associated with lower elevations with higher percent ground cover of litter than sites without it. Silene spaldingii was more likely to be absent in sites with higher percent canopy cover of native annual forbs, total exotic species, and exotic annual grasses and forbs. Silene spaldingii was more likely to be absent from sites with higher species richness of exotic annual grasses and forbs, exotic perennial grasses, and total species richness. Canopy cover of exotic annual forbs and species richness were the best predictors of the absence of Silene spaldingii. My research v suggests that competition for resources by exotic species invasions seems to be a factor explaining the absence of Silene spaldingii from otherwise suitable habitat. Recruitment of new plants by Silene spaldingii is most likely the limiting factor in population growth. Silene spaldingii inhabits mid to late seral native perennial bunchgrass communities with few exotic species, and that appear to be resistant to exotic invasions when undisturbed. Silene spaldingii is an indicator of high quality steppe habitat. The amount of insect herbivory, yellowing of plants in June, and non-reproductive stems were different between pastures, but the reasons were not clear. Monitoring for weed invasions and active management to reduce weed infestations are important steps towards protecting the Silene spaldingii population. Yearly, long-term monitoring of patterns in population, community, and vigor characteristics could help us understand the status of the Smoothing Iron population.
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Details
- Title
- Silene spaldingii (Spalding's catchfly) population vigor and community characteristics in Asotin County, Southeastern Washington
- Creators
- Taryn Beth. Clark
- Contributors
- Linda H. Hardesty (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Agricultural, Human, and Natural Resource Sciences, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525102801842
- Language
- English
- Resource Type
- Thesis