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Institution

Alberta Environment

GovernmentEdmonton, Alberta, Canada
About: Alberta Environment is a government organization based out in Edmonton, Alberta, Canada. It is known for research contribution in the topics: Oil sands & Population. The organization has 345 authors who have published 441 publications receiving 9510 citations.


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Journal ArticleDOI
01 Jun 1994-Ecology
TL;DR: The measurement of gross rates of N transfor- mations in soil provides a powerful tool for assessing C and N cycling relationships in forests, and the utilization of lower quality substrates as C availability declined during incubation is suggested.
Abstract: We conducted a 456-d laboratory incubation of an old-growth coniferous forest soil to aid in the elucidation of C controls on N cycling processes in forest soils. Gross rates of N mineralization, immobilization, and nitrification were measured by 'IN isotope dilution, and net rates of N mineralization and nitrification were calculated from changes in KCl-extractable inorganic N and NOE-EN pool sizes, respectively. Changes in the availability of C were assessed by monitoring rates of CO, evolution and the sizes of extractable organic C and microbial biomass pools. Net and gross rates of N mineralization (r2 = 0.038, P =.676) and nitrification (r2 = 0.403, P = .125) were not significantly correlated over the course of the incubation, suggesting that the factors controlling N consumptive and productive processes do not equally affect these processes. A significant increase in the NO, pool size (net nitrification) only occurred after 140 d, when the NO3- pool size increased suddenly and massively. However, gross nitrification rates were substantial throughout the entire incubation and were poorly correlated with these changes in NO3 pool sizes. Concurrent decreases in the microbial biomass suggest that large increases in NO3 pool sizes after prolonged incubation of coniferous forest soil may arise from re- ductions in the rate of microbial immobilization of NO3, rather than from one of the mechanisms proposed previously (e.g., sequestering of NH,+ by microbial heterotrophs, the deactivation of allelopathic compounds, or large increases in autotrophic nitrifier pop- ulations). Strong correlations were found between rates of CO2 evolution and gross N mineralization (r2 = 0.974, P < .0001) and immobilization (r2 = 0.980, P < .0001), but not between CO, evolution and net N mineralization rates. Microbial growth efficiency, determined by combining estimates of gross N immobilization, CO2 evolution, and micro- bial biomass C and N pool sizes, declined exponentially over the incubation. These results suggest the utilization of lower quality substrates as C availability declined during incu- bation. Results from this research indicate the measurement of gross rates of N transfor- mations in soil provides a powerful tool for assessing C and N cycling relationships in forests.

716 citations

Journal ArticleDOI
TL;DR: The boreal woodlands and forests cover approximately 3.09 × 106 km2 in Canada and are characterized by cool summers and long cold winters as discussed by the authors, and have been warm since the 1850s.
Abstract: Canadian boreal woodlands and forests cover approximately 3.09 × 106 km2, located within a larger boreal zone characterized by cool summers and long cold winters. Warming since the 1850s, increases...

429 citations

Journal ArticleDOI
TL;DR: In this paper, the Recruitment Box Model is used to predict the flow regime of a river during high flow years to encourage the recruitment of cottonwoods and willows along previously impoverished reaches.
Abstract: River damming has dramatic environmental impacts and while changes due to reservoir flooding are immediate, downstream impacts are more spatially extensive. Downstream environments are influenced by the pattern of flow regulation, which also provides an opportunity for mitigation. We discuss impacts downstream from dams and recent case studies where collaborative efforts with dam operators have led to the recovery of more natural flow regimes. These restoration programs, in Nevada, USA, and Alberta, Canada, focused on the recovery of flow patterns during high flow years, because these are critical for riparian vegetation and sufficient water is available for both economic commitments and environmental needs. The restoration flows were developed using the “Recruitment Box Model”, which recommends high spring flows and then gradual flow decline for seedling survival. These flow regimes enabled extensive recruitment of cottonwoods and willows along previously impoverished reaches, and resulted in improvements to river and floodplain environments. Such restoration successes demonstrate how instream flow management can act as a broadly applicable tool for the restoration of floodplain forests.

307 citations

Journal ArticleDOI
TL;DR: An overview of current research in isotope hydrology focusing on recent Canadian contributions is discussed under the headings: precipitation networks, hydrograph separation and groundwater studies, river basin hydrology, lake and catchment water balance, and isotope palaeohydrology from lake sediment records as discussed by the authors.
Abstract: An overview of current research in isotope hydrology, focusing on recent Canadian contributions, is discussed under the headings: precipitation networks, hydrograph separation and groundwater studies, river basin hydrology, lake and catchment water balance, and isotope palaeohydrology from lake sediment records. Tracer-based techniques, relying primarily on the naturally occurring environmental isotopes, have been integrated into a range of hydrological and biogeochemical research programmes, as they effectively complement physical and chemical techniques. A significant geographic focus of Canadian isotope hydrology research has been on the Mackenzie River basin, forming contributions to programmes such as the Global Energy and Water Cycle Experiment. Canadian research has also directly supported international efforts such as the International Atomic Energy Agency’s (IAEA) Global Network for Isotopes in Precipitation and IAEAs Coordinated Research Project on Large River Basins. One significant trend in Canadian research is toward sustained long-term monitoring of precipitation and river discharge to enable better characterization of spatial and temporal variability in isotope signatures and their underlying causes. One fundamental conclusion drawn from previous studies in Canada is that combined use of υ 18 O and υ 2 H enables the distinction of precipitation variability from evaporation effects, which offers significant advantages over use of the individual tracers alone. The study of hydrological controls on water chemistry is one emerging research trend that stems from the unique ability to integrate isotope sampling within both water quality and water quantity surveys. Copyright  2005 John Wiley & Sons, Ltd.

304 citations

Journal ArticleDOI
TL;DR: Both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations.
Abstract: Agricultural intensification is a leading cause of global biodiversity loss, which can reduce the provisioning of ecosystem services in managed ecosystems. Organic farming and plant diversification are farm management schemes that may mitigate potential ecological harm by increasing species richness and boosting related ecosystem services to agroecosystems. What remains unclear is the extent to which farm management schemes affect biodiversity components other than species richness, and whether impacts differ across spatial scales and landscape contexts. Using a global metadataset, we quantified the effects of organic farming and plant diversification on abundance, local diversity (communities within fields), and regional diversity (communities across fields) of arthropod pollinators, predators, herbivores, and detritivores. Both organic farming and higher in-field plant diversity enhanced arthropod abundance, particularly for rare taxa. This resulted in increased richness but decreased evenness. While these responses were stronger at local relative to regional scales, richness and abundance increased at both scales, and richness on farms embedded in complex relative to simple landscapes. Overall, both organic farming and in-field plant diversification exerted the strongest effects on pollinators and predators, suggesting these management schemes can facilitate ecosystem service providers without augmenting herbivore (pest) populations. Our results suggest that organic farming and plant diversification promote diverse arthropod metacommunities that may provide temporal and spatial stability of ecosystem service provisioning. Conserving diverse plant and arthropod communities in farming systems therefore requires sustainable practices that operate both within fields and across landscapes.

235 citations


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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20221
202155
202051
201963
201849
201732