Understanding the controls on water movement on forested uplands is critical in predicting the potential effects of disturbance on the sustainability of water resources. I examined the controls on vertical and lateral water movement on forested uplands on a range of landforms (coarse textured outwash, fine textured moraine) and time periods (individual events, during snowmelt, through the growing season, annually, and long-term) at the Utikuma Region Study Area (URSA) on the sub-humid Boreal Plains of Alberta, Canada. To quantify vertical and lateral water movement, hydrometric and tracer measurements were made under natural and experimental conditions at plot and hillslope scales. Vertical flow and unsaturated zone storage dominated hydrologic response to snowmelt and rainfall at the plot and hillslope scales. Plot-scale snowmelt infiltration was greater than near-surface runoff, and when runoff occurred it was limited to south-facing outwash hillslopes underlain by concrete frost. Rainfall simulation studies showed that even under the extreme conditions tested, vertical flow and storage dominated the hydrologic response. Soils at field capacity and precipitation inputs of 15-20 mm or greater at high intensities were required to generate lateral flow via the transmissivity feedback mechanism. The threshold soil moisture and precipitation conditions are such that lateral flow will occur infrequently under natural conditions. Seasonal vertical water movement under natural conditions was greater on outwash than moraine uplands. The maximum downward vertical movement occurred in response to snowmelt, with little subsequent movement over the growing season. Recharge following snowmelt was similar for outwash and moraine sites and was followed by declining water tables through the growing season. Tracer estimates of long-term root zone drainage were low, while estimates of recharge for the moraine were high, raising questions about the appropriateness of this method for these sites. These results emphasize the dominance of vertical relative to lateral water flow on Boreal Plain uplands. Detailed understanding of the controls on water movement can be used to predict the potential effects of disturbance on hydrology and water resources. / Ecology

主催：JST/CREST，Vrije University, ALTERRA, IBPC

No description available.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2005. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 6 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

Thesis (M.S.)--Brigham Young University. Dept. of Integrative Biology, 2006. / Includes bibliographical references (p. 27-34).

Recent studies applying innovative technologies, such as genetic analysis and carbon dating, contradict the palynological based assumption that Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) vanished from Fennoscandia during the Last Glacial Maximum (c. 20.000 yrs BP) and re-colonized after the cold Younger Dryas (c. 12.000 yrs BP). Instead, those studies indicate glacial survival of boreal trees in ‘cryptic’ refugia within Scandinavia, which is still heavily debated. In this report, I try to get a better grip on the discussion if Norway spruce and Scots pine survived Weichselian glacial periods in isolated ‘cryptic’ refugia within Scandinavia, or either re-colonized Fennoscandia by post-glacial migration from eastern areas such as Russia. To this aim, climatic settings are described and an overview is given on what is already known on the distribution of boreal trees during the Weichselian glaciations and the post-glacial landscape. Several records are important to detect ancient boreal trees: pollen, macrofossils and currently DNA. Macrofossils indicate early post-glacial tree growth in the central Scandes just after the Younger Dryas, aDNA indicates the existence of a ‘cryptic’ refugium on Andøya during the Last Glacial Maximum and modern DNA analysis possibly indicates isolation of spruce in western Norway, which are all contradicted by the current interpretation of low pollen percentages. Altogether, alternative hypotheses supporting glacial survival of plants might have been overlooked and pollen interpretations need revision, which could turn the exclusion from the past into supporting evidence for the glacial survival of P. abies and P. sylvestris in Scandinavia.

The aim of this study was to determine if the occurrence, thalli length and cover of the epiphytic lichens Alectoria sarmentosa, Bryoria capillaris and Usnea dasypogea differ between sites with inland and coastal climate in Norrbotten county, Sweden. The trunk and branch diameter of the Picea abies trees, on which the lichens were inventoried, were measured as well. B. capillaris was the most common lichen species in both habitats. B. capillaris and A. sarmentosa had significant higher percentage occurrence in inland sites, while the occurrence of U. dasypogea was higher in the coastal sites. For B. capillaris, the percentage cover per branch was also higher in inland than in coastal sites. No significant difference in thallus lengths were found for any species. Obtained climate data suggest that humidity is higher inland, which is favourable for B. capillaris. Litterateur suggest that of all studied species, B. capillaris is the most common species in colder climates while A. sarmentosa is an intermediate and U.dasypogea is a lichen species normally occurring in warmer climates, which might explain their observed occurrence pattern outcome of the study. Linear regression was executed as well where only A.sarmentosa had significant and positive relationships to branch diameter. Other studies support the correlation with branch diameter but not with trunk diameter.

Peatland ecosystems are important as natural climate regulators for their capacity to store carbon over long-time scales. Carbon cycling in peatlands in the boreal ecozone of Canada has been more widely studied than the boreal shield of Ontario, where peat depths are thinner and peatlands spatially smaller. The reliance on fill and spill hydrologic connectivity makes the water table dynamics of peatlands in Ontario’s Eastern Georgian Bay (EGB) region of the Ontario shield ecozone sensitive to rain and drought periods. The drying of wetlands in the EGB region decreases moss productivity and increases the ecosystem’s vulnerability to wildfire through an increase in the water table depth. In an effort to understand how peatlands respond to interannual climate variability and wildfire, we examined the role of regional climate patterns on growing season CO2 exchange from an Ontario shield peatland and completed a post-wildfire assessment of CO2 exchange patterns in a recently burned peatland for the first and second year post-wildfire. Using the eddy covariance technique, we analyzed 5-years of growing season CO2 exchange data from 2016 to 2020 from an unburned peatland and 2-years of growing season CO2 exchange data from a burned peatland (2019-2020) in EGB. Plot-scale CO2 exchange measurements were also completed within the burned peatland jointly with abiotic variables and vegetation community surveys. Water table depth was identified as an important variable to explain total summer CO2 uptake (GPP) and net ecosystem exchange (NEE), where years of considerable rainfall maintained a water table near the peat surface and perpetuated high vegetation productivity. Summer total ecosystem respiration (ER) was greatly influenced by preceding winter and spring air temperature, with warmer winter air temperatures leading to summers of increased total ER. Warmer winter air temperatures also initiated water flow across the landscape, thus reviving plant and microbial activity following snow cover. These findings have important implications for the function of these shallow Ontario shield peatlands in a warming climate, where decreased water availability with projected increased temperatures and evapotranspiration leaves peatlands at risk of a net loss of C over the summer with lower water table. In the burned landscape, there was lower GPP in the summer (2019) compared to the wet summer of 2020, however the burned landscape continued to act as a net CO2 sink for the summer season of both years. The rapid recovery of vegetation across the wildfire-disturbed landscape has important implications for the function of these peatlands over time, with the ability for continued carbon uptake and reinstating peat accumulation processes. / Thesis / Master of Science (MSc)