Hydrological processes as function of vegetation type in six vegetation communities in a maritime raised bog
department or school: Arts, Faculty of
department or school: Geography, Department of
data provider: DSpace
degree campus: UBCV
creator: Exler, Johannes
issued: 2023-08-17T18:48:39Z
issued: 2023
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Climate change and widespread drainage of peatlands are two main drivers behind shifts in peatland vegetation composition. Peatlands rely on shallow water levels that reduce peat oxidation rates to levels less than carbon accumulation. However, climatic warming and drainage enable non-native vegetation to encroach in areas of lowered groundwater levels where increased water loss due to plant activity cause groundwater levels to drop further. This research aimed at improving the understanding of how drainage and projected climatic change in the Pacific Northwest of North America may affect the hydrology of ombrotrophic raised bogs in the region through associated vegetation community shifts. Research was conducted in a raised bog in southwestern British Columbia, which has a history of drainage that enabled vegetation communities of different structure and species composition to establish. Multi-year energy and water flux and storage observations at an open site near the bog's center identified available energy and atmospheric demand, expressed as vapour pressure deficit (VPD), to be the main drivers of evapotranspiration loss (ET) at a daily time scale, and groundwater level was a secondary control. Interannual variability of growing season ET was driven by differences in VPD. The dominant water loss process shifted from ET in summer to lateral near-surface and surface flow in winter, which was controlled by two groundwater level thresholds. Vertical water exchange fluxes between the peat surface and the atmosphere were a function of vegetation type. A reduction in net precipitation was primarily associated with shrub interception loss, which was higher than interception loss from trees on a per unit ground area basis. At the tree level, transpiration loss was a function of tree size and species; groundwater level was a secondary species-specific control in the short term. Differences in root development between sites that affected stand transpiration were likely a …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/85505
note: Hydrological processes as function of vegetation type in sixvegetation communities in a maritime raised bogbyJohannes ExlerA DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THEREQUIREMENTS FOR THE DEGREE OFDOCTOR OF PHILOSOPHYinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Geography)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)August 2023© Johannes Exler, 2023The following individuals certify that they have read, and recommend to the Faculty ofGraduate and Postdoctoral Studies for acceptance, the dissertation entitled:Hydrological processes as function of vegetation type in six vegetationcommunities in a maritime raised bogsubmitted by Johannes Exler in partial fulfillment of the requirements for the degree of Doctor of Philosophyin GeographyExamining Committee:Robert Daniel Moore, Professor, Geography, UBCSupervisorSara Knox, Associate Professor, Geography, UBCSupervisory Committee MemberIan McKendry, Professor, Geography, UBCUniversity ExaminerAndrew Black, Professor, Land and Food Systems, UBCUniversity ExaminerAdditional Supervisory Committee Members:Roger Beckie, Professor, Earth, Ocean and Atmospheric Sciences, UBCSupervisory Committee MemberMark Johnson, Professor, Institute for Resources, Environment and Sustainability, UBCSupervisory Committee MemberiiAbstractClimate change and widespread drainage of peatlands are two main drivers behind shiftsin peatland vegetation composition. Peatlands rely on shallow water levels that reducepeat oxidation rates to levels less than carbon accumulation. However, climatic warmingand drainage enable non-native vegetation to encroach in areas of lowered groundwaterlevels where increased water loss due to plant activity cause groundwater levels to dropfurther. This research aimed at improving the understanding of how drainage and projectedclimatic change in the Pacific Northwest of North America may affect the hydrology ofombrotrophic raised bogs in the region through associated vegetation community shifts.Research was co…
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0435263
language: eng
degree discipline: Geography
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Moore, R. Daniel
type: Text
identifier URI: http://hdl.handle.net/2429/85505