Date of Graduation
5-2016
Document Type
Thesis
Degree Name
Bachelor of Science
Degree Level
Undergraduate
Department
Biological Sciences
Advisor/Mentor
Evans-White, Michelle
Committee Member/Reader
Alverson, Andrew
Committee Member/Second Reader
Thallapuranam, Suresh
Abstract
Unconventional natural gas (UNG) is harvested using a unique fossil fuel extraction method that uses horizontal drilling and hydraulic fracturing techniques. The combined methods have expanded the industry both nationally and globally, and development has the ability to transform landscapes and impact freshwater resources. Natural gas wells are often near streams, yet substantial knowledge gaps remain as to how and the extent to which development affects surface waters. Stream algal biomass can respond positively to anthropogenic stressors associated with different types of land use, including agriculture. Benthic algal biomass can also positively correlate with UNG well density and proximity to streams in the Fayetteville shale, but wells are often associated with agricultural land that may confound the relationship.
The first objective of the present study was to determine if stream benthic algal biomass related to previously developed metrics of sensitivity, exposure, and vulnerability to land use change. These metrics incorporated landscape measures of UNG development, an emerging human land use change that may affect stream ecosystems. The second objective was to determine if the relationships among algal biomass and the metrics differed in streams draining lands with and without the presence of UNG wells. Forty stream reaches in the Fayetteville shale were sampled that represented a gradient of vulnerability scores (hereafter, Vulnerability), and analysis of covariance was used to determine if algal biomass, measured as Chlorophyll a, differed based on land use type across a covariate score. The results indicated no relationship between Chlorophyll a and Vulnerability or its two individual metrics, Sensitivity and Exposure (p>0.50 for all scores). There was no difference in Chlorophyll a between sites with and without UNG wells present. I suggest modifications to the vulnerability index that might yield an overall Vulnerability effect as well as additional considerations for choosing a response metric.
Citation
Verkamp, H. J. (2016). Stream benthic algal relationships with multi-metric indices of sensitivity, exposure, and vulnerability to watershed land use change, with an emphasis on unconventional natural gas development. Biological Sciences Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/biscuht/15