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  1. Climatic and anthropogenic effects on atmospheric mercury accumulation rates in ombrotrophic bogs from Southern Ontario [Download]

    Title: Climatic and anthropogenic effects on atmospheric mercury accumulation rates in ombrotrophic bogs from Southern Ontario
    Creator: Givelet, N.
    Subjects: Atmospheric elements, Peat bogs, Mercury
    Date Created: 2003
  2. Analytical procedures for the determination of selected trace elements in age dated peat profiles [Download]

    Title: Analytical procedures for the determination of selected trace elements in age dated peat profiles
    Creator: Krachler, M.
    Subjects: Peat bogs, Age-dated profiles, Trace elements
    Date Created: 2003
  3. Managing fire for woodland caribou in Jasper and Banff National Parks [Download]

    Title: Managing fire for woodland caribou in Jasper and Banff National Parks
    Creator: Shepherd, L.
    Description: Abstract: Woodland caribou (Rangifer tarandus caribou) populations in Jasper (JNP) and Banff National Parks (BNP) have declined since the 1970s, coincident with reduced fire activity in both parks, relative to historic levels. Some researchers have suggested that long periods without fire may cause habitat deterioration for woodland caribou, primarily by reducing available lichen forage. We examined winter habitat selection by woodland caribou at coarse and fine scales based on GPS-derived telemetry data and used models that included stand origin (decade), topography, and several stand structure variables that are related to time since fire, to explore relationships among caribou, lichen, and fire history. Based on the relationships illustrated by the models, we assessed how fire management could be applied to caribou conservation in JNP and BNP. At a coarse scale, caribou selected old forest (> 75 years) in landscapes that have likely experienced less frequent wildfire. While the abundance of Cladonia spp. influenced caribou use at fine scales, a preference for areas with older trees within stands was also significant. We conclude that short-term habitat protection for woodland caribou in JNP and BNP likely requires fire exclusion from caribou range.
    Subjects: Rangifer tarandus caribou, Fire management, Resource selection functions, Lichen, Forage, Multi-scale models, Habitat, Cladonia, Generalized linear models
    Date Created: 2007
  4. Evaluation of carabid beetles as indicators of forest change in Canada [Download]

    Title: Evaluation of carabid beetles as indicators of forest change in Canada
    Creator: Work, T.T.
    Description: Our objective was to assess the potential of carabid beetles (Coleoptera: Carabidae) as effective bioindicators of the effects of forest management at a Canadian national scale. We present a comparison of carabid beetle assemblages reported from large-scale Studies across Canada. Based on the initial response following disturbance treatment, we found that carabid assemblages consistently responded to disturbance, but responses of individual species and changes in species composition were nested within the context of regional geography and finer scale differences among forest ecosystems. We also explored the relationship between rare and dominant taxa and species characteristics as they relate to dispersal capacity and use of within-stand habitat features such as coarse woody debris. We found no relationship between life-history characteristics (such as body size, wing morphology, or reported associations with downed wood) and the relative abundance Or frequency Of occurence of species. Our results suggest that carabids are better suited to finer scale evaluations of the effects of forest management than to regional or national monitoring programs. We also discuss several knowledge gaps that currently limit the full potential of using carabids as bioindicators.
    Subjects: Habitat fragmentation, Pitfall traps, Ground beetles, Patterns, Coleoptera, Boreal forest, Abundance, Management, Assemblages, Quebec
    Date Created: 2008
  5. A 6,000 year record of atmospheric mercury accumulation in the high Arctic from peat deposits on Bathurst Island, Nunavut, Canada [Download]

    Title: A 6,000 year record of atmospheric mercury accumulation in the high Arctic from peat deposits on Bathurst Island, Nunavut, Canada
    Creator: Givelet, N.
    Subjects: Atmospheric elements, Mercury, Peat bogs
    Date Created: 2003
  6. High-resolution AMS 14C dating of post bomb peat archives of atmospheric pollutants [Download]

    Title: High-resolution AMS 14C dating of post bomb peat archives of atmospheric pollutants
    Creator: Goodsite, M. E.
    Description: ABSTRACT. Peat deposits in Greenland and Denmark were investigated to show that high-resolution dating of these archives of atmospheric deposition can be provided for the last 50 years by radiocarbon dating using the atmospheric bomb pulse. 14C was determined in macrofossils from sequential one cm slices using accelerator mass spectrometry (AMS). Values were calibrated with a general-purpose curve derived from annually averaged atmospheric 14CO2 values in the northernmost northern hemisphere (NNH, 30°–90°N). We present a thorough review of 14C bomb-pulse data from the NNH including our own measurements made in tree rings and seeds from Arizona as well as other previously published data. We show that our general-purpose calibration curve is valid for the whole NNH producing accurate dates within 1–2 years. In consequence, 14C AMS can precisely date individual points in recent peat deposits within the range of the bomb-pulse (from the mid-1950s on). Comparing the 14C AMS results with the customary dating method for recent peat profiles by 210Pb, we show that the use of 137Cs to validate and correct 210Pb dates proves to be more problematic than previously supposed. As a unique example of our technique, we show how this chronometer can be applied to identify temporal changes in Hg concentrations from Danish and Greenland peat cores.
    Subjects: Radiocarbon dating, Peat
    Date Created: 2002
  7. Effects of crop rotation and genetically modified herbicide-tolerant corn on ground beetle diversity, community structure and activity density [Download]

    Title: Effects of crop rotation and genetically modified herbicide-tolerant corn on ground beetle diversity, community structure and activity density
    Creator: Bourassa, S.
    Description: Ground beetles (Coleoptera. Carabidae) were sampled in conventional and genetically modified herbicide-tolerant (GM HT) corn, Zea mays L. (Poaceae), planted under rotation with canola, Brassica L. (Brassicaceae), or continuously cropped corn to investigate the influence of corn variety and rotation on the structure of carabid assemblages Corn variety, cultivation regime, and their interaction all influenced overall carabid activity density. Weed management associated with corn variety influenced the activity density of a few carabid species and this was attributed to changes in vegetation. Some smaller bodied carabids such as Bembidion quadrimaculatum L. were less abundant in GM HT plots, probably because weed density was higher in midseason, but the opposite was observed for larger bodied carabids such as Pterostichus melanarius (Illiger). Overall, rotating corn with canola had a stronger effect on carabid community structure than did corn variety. We suggest that GM HT corn has little impact on the overall carabid fauna but may influence the activity of certain species through effects on the weed community.
    Subjects: Predation, Populations, Assemblages coleoptera, Arthropods, Farm scale evaluations, Weeds, Strip-management, Cereal fields, Carabid beetles, Invertebrate responses
    Date Created: 2010
  8. Wing-dimorphism and population expansion of Pterostichus melanarius (Illiger, 1798) at small and large scales in central Alberta, Canada (Coleoptera, Carabidae, Pterostichini) [Download]

    Title: Wing-dimorphism and population expansion of Pterostichus melanarius (Illiger, 1798) at small and large scales in central Alberta, Canada (Coleoptera, Carabidae, Pterostichini)
    Creator: Bourassa, S.
    Description: Abstract: A study spanning ten years revealed changes in wing-morph ratios corroborating the hypothesis that the wing-dimorphic introduced carabid, Pterostichus melanarius Ill., is spreading through flight, from the city of Edmonton, Canada and establishing populations in natural aspen forest of more rural areas 45-50 km to the East. Comparison of wing-morph ratios between P melanarius and the native wing dimorphic species Agonum retractum LeConte suggests that the spatial variation in ratios for P. melanarius does not reflect underlying environmental variation, but instead the action of selective forces on this wing-dimorphic species. About ten years after its earliest detection in some rural sites the frequency of macropterous individuals in P. melanarius has decreased c. five-fold, but it is still above the level seen in European populations in which the two wing-morphs are thought to exist in equilibrium. P. melanarius is expanding its range in native aspen forest much faster than three other introduced species Clivina fossor L.), Carabus granulatus O.F. Muller and Clivina fossor L also encountered in this study. The two Carabus species are flightless, but C. fossor can be dimorphic. Although these four non-native ground beetle species comprise >85% of the carabids collected at sites in urban Edmonton, activity-density of native carabids was similar across the urban-rural gradient, suggesting little direct impact of introduced species on the local abundance of native species. In a second study conducted at a smaller scale near George Lake, Alberta, macropterous individuals of P. melanarius have penetrated furthest and most rapidly into native aspen forest. Furthermore, the percentage of micropterous individuals has increased markedly in areas first colonized a decade previously. Overall, these studies support the idea that macropterous beetles in wing-d dimorphic species are important vanguards for early colonization of unexploited territory, but that flightless individuals replace the flying morph relatively rapidly once populations are established.
    Subjects: Pterostichus melanarius, Wing-dimorphism
    Date Created: 2011
  9. Saproxylic insect assemblages in Canadian forests: diversity, ecology and conservation [Download]

    Title: Saproxylic insect assemblages in Canadian forests: diversity, ecology and conservation
    Creator: Langor, D. W.
    Description: Saproxylic insect assemblages inhabiting dead wood in Canadian forests are highly diverse and variable but quite poorly understood. Adequate assessment of these assemblages poses significant challenges with respect to sampling, taxonomy, and analysis. Their assessment is nonetheless critical to attaining the broad goals of sustainable forest management because Such species are disproportionately threatened elsewhere by the reductions in dead wood generally associated with commercial exploitation of northern forests. The composition of the saproxylic fauna is influenced by many factors, including tree species, degree of decay, stand age, and cause of tree death. Wildfire and forest harvesting have differential impacts on saproxylic insect assemblages and on their recovery in postdisturbance stands. Exploration of saproxylic insect responses to variable retention harvesting and experimental burns is contributing to the development of prescriptions for conserving saproxylic insects in boreal forests. Understanding of processes that determine diversity patterns and responses of saproxylic insects Would benefit front increased attention to natural history. Such work Should aim to provide a habitat-classification system for dead wood to better identify habitats (and associated species) at risk its a result of forest management. This tool Could also be used to improve strategies to better maintain saproxylic organisms and their central nutrient-cycling functions in managed forests.
    Subjects: Dead wood, Growth boreal forests, Species richness, Beetles coleoptera, Decaying wood, Coarse woody debris, Community composition, Natural-disturbance, Spruce forests, Southeastern Ontario
    Date Created: 2008
  10. Conservation of forest-dwelling arthropod species: simultaneous management of many small and heterogeneous risks [Download]

    Title: Conservation of forest-dwelling arthropod species: simultaneous management of many small and heterogeneous risks
    Creator: Spence, J. R.
    Description: The Canadian insect fauna is too inadequately Understood to support well-informed assessments about its conservation status: however, the foregoing collection of synthetic papers illustrates potential threats front industrial forestry. Loss of forest species and dramatic changes in forest insect assemblages driven by forestry activities are well illustrated by studies front places where industrial forest management has been more intensive or of longer duration. Improved Understanding of how arthropod species are coupled to habitats, especially microhabitats. appears to be central to progress toward their conservation. Studies of arthropods conducted at the species level are most relevant for applied conservation purposes. because only species-level work that is well documented with voucher specimens provides adequate comparative data to document faunal change. Although taxonomic infrastructure required to support such work is seriously under-resourced in Canada, entomologists can help themselves by producing useful modern resources for species identification, by Undertaking collaborative biodiversity work that minimizes the split between taxonomists and ecologists. and by supporting incentives for work at the species level. Securing the future of arthropod diversity ill Canadian forests through effective policy will require Sound regionally defined bases for whole-fauna conservation that mesh with broader land-Use planning. Building, these will require a practical Understanding of how \"ecosite-classification systems relate to arthropod diversity, accurate inventories of the predisturbance forest fauna in all regions, and development of sound monitoring plans designed to both detect faunal change efficiently and identify its drivers. such monitoring plans should include both baseline inventories and monitoring, of designated control areas. In addition, ef fective biomonitoring efforts will facilitate the development of suites of arthropod indicators, accommodate both seasonal (especially phenological) and annual variation, clarify the relationship between cost-effective samples and reality, and ensure adequate consideration of \"rare\" species. Return oil investment in monitoring, will depend Oil effective preplanned linkage to policy development that call respond to drivels of faunal change in a way that effectively addresses undesired changes.
    Subjects: Carabid beetles, Boreal forests, Beetle assemblages coleoptera, Extinction debt, Habitat fragmentation, Natural disturbance, Western Canada, Fire residuals, Indicators, Integrating biodiversity
    Date Created: 2008