Measuring the effects of road mediated long-range transport on infection risk for Port Orford cedar
Graduation Date
2014
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Environmental Systems: Mathematical Modeling, 2014
Committee Chair Name
Christopher Dugaw
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Humboldt State University -- Theses -- Mathematical Modeling, Survival analysis, Phytophthora lateralis, Biological invasion, Root pathogen
Abstract
Biological invasions are an important topic in today's global economy. Thousands of animals, plants, and pathogens are being transported through human activity into new ecosystems with sometimes disastrous consequences. Phytophthora lateralis is a water-borne invasive root pathogen that is currently affecting Port Orford Cedar in riparian zones. Once a tree near a stream is infected the pathogen spreads rapidly down the stream. Thus it is reasonable to consider the infection of streams as opposed to individual trees. Probability of infection for stream crossings within the study site are hypothesized to depend on environmental factors and logging traffic. Data on infection dates, environmental variables, and logging traffic was collected for 77 stream crossings. The data were then used to parametrize infection probability models using maximum likelihood methods and optimization. The resulting model set was analyzed using AICc. Site characteristics were found to be significant and logging traffic was found to be somewhat significant.
Recommended Citation
O'Kane, Drew E., "Measuring the effects of road mediated long-range transport on infection risk for Port Orford cedar" (2014). Cal Poly Humboldt theses and projects. 1162.
https://digitalcommons.humboldt.edu/etd/1162
https://scholarworks.calstate.edu/concern/theses/9z903215q