Midterm impacts of fire severity on headwater stream ecosystems in the Klamath Mountains, California
Graduation Date
2015
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Natural Resources: Environmental Studies, 2015
Committee Chair Name
Alison O’Dowd
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Headwater stream ecosystems, Wildfires, Humboldt State University -- Theses -- Natural Resources, Riparian areas
Abstract
Wildfire disturbances in riparian areas can impact stream chemistry, primary production, and trophic dynamics for years to decades after burning. Previous studies in headwater streams have focused on immediate and short term impacts, while effects during the midterm (1-10y) post-fire period are less understood. To evaluate responses of headwater stream communities 6-8 y post-fire, I compared water chemistry, benthic macroinvertebrate assemblages and periphyton biomass as chlorophyll a concentrations from 19 headwater streams categorized as unburned (n=5), low fire severity (n=5), moderate fire severity (n=4), or high fire severity (n=5). The hypothesized relationship between lower canopy densities and increased periphyton biomass was detected in moderate and high fire severity streams (p=0.008). Comparisons of feeding group ratios representing relative numerical abundances versus relative biomass of algal to detrital consumers indicated elevated biomass of algal consumers in high fire severity streams (p=0.05). Indirect ordination showed major overlap in community composition among severity categories, suggesting a general return to pre-disturbance stable states. These findings inform understanding of post-fire processes of Klamath Mountain aquatic ecosystems during a time when climatic and human-related changes have degraded aquatic habitats and increased the frequency and size of wildfires in the region.
Recommended Citation
Ferrell, Emily K., "Midterm impacts of fire severity on headwater stream ecosystems in the Klamath Mountains, California" (2015). Cal Poly Humboldt theses and projects. 1826.
https://digitalcommons.humboldt.edu/etd/1826
https://scholarworks.calstate.edu/concern/theses/z316q3719