4,149 research outputs found

    Nationwide forestry applications program. Ten-Ecosystem Study (TES) site 6, Fort Yukon, Alaska

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    The author has identified the following significant results. Analysis of the processing results has led to the following conclusions: (1) LANDSAT imagery was a reliable resource for the stratification of level 2 forest features (softwood, hardwood, tundra, and water). These features can be classified with an accuracy of 72.4 percent + or - 5.9 percent at the 90 percent confidence level. (2) Training fields selected for signature development from only 10 percent of the area did not adequately and efficiently cover the class variability for the entire area. (3) Derived regression transformations were ineffective in recovering the loss of level 1 forest proportions and level 2 softwood and hardwood proportions

    Shrub expansion in Arctic Alaska: 50 years of change documented using aerial photography

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    Thesis (M.S.) University of Alaska Fairbanks, 2004Evidence from arctic Alaska suggests that the terrestrial landscape is changing in response to warming. Between 1946 and 1951, several thousand low-altitude panchromatic oblique aerial photographs were taken as part of geologic reconnaissance and exploration of Alaska's Arctic Slope and Brooks Range. For this study, 202 of the landscapes in the old photographs were re-photographed. Comparison of the old and new photographs revealed an increase in shrub cover in the last half-century. The changes were observed over a 220,000 km2 tract of arctic tundra, and it is likely that they are more widespread. A quantitative method for comparing the photographs yielded an increase in alder shrub cover from 14 to 20%, with similar increases observed for willow and birch shrubs. This shrub expansion was observed in many landscape positions, including hill slopes, river terraces, and also river floodplains, where the increase in shrub vegetation has resulted in the narrowing and stabilization of floodplains. The regional expansion of shrubs documented in the photographs can only be explained by a perturbation operating on a similarly large scale. In the absence of large-scale disturbances like fire, the increase in shrubs documented here is most likely to be a product of elevated temperatures and other changes in climate favorable to shrub growth

    What is the impact of a UNSECO status due to visitors on the environment of Herschel Island? - A survey of the influence of trampling on vegetation

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    With rising global tourism demand for wilderness and pristine habitats, the evaluation ofanthropogenic impacts on the environment and preservation efforts has become more andmore important. This study focuses on the Territorial Park Herschel Island Qikiqtaruk in the western Canadian Arctic, which has been on the tentative list for becoming a culturaland natural World Heritage Site since 2004. Thee study was conducted to determine thepotential impacts of a designation in terms of visitor development and trampling disturbances. A thorough literature review suggested a likely increase of tourist numbers after the granting of the World Heritage Status. In this thesis several visitor groups to Herschel Island were included, with a special focus on two main groups: cruise ship visitors and researchers, which make the bulk part of visitors to the territorial park. Park rangers and researchers helped to delineate trails commonly used by cruise ship visitors. GPS and DGPS datasets collected by researchers over the 2014-2017 period were used to show areasfrequently visited for research activities. In general, impacts from anthropogenic trampling directly result from the intensity of trampling but also vary substantially depending on the condition of the vegetation composition. The study identified two ecological classes overwhelmingly impacted by cruiseship visitors and where trail development might occur in the future. The paths used by researchers are more dispersed and the resulting light but steady trampling was also shownto result in vegetation alteration. The impact of visitor disturbance on permafrost could not be evaluated directly on site, but a thorough literature review has shown a strong interrelationship between vegetation disturbances, trampling and permafrost thaw. In conclusion, this thesis formulated and discussed several recommendations for Herschel Island Qikiqtaruk Territorial Park to mitigate effects of visitor impacts on vegetation,which are likely to increase with a rising number of visitors

    Studies of Birds and Mammals in the Baird and Schwatka Mountains, Alaska

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    In 1963 a joint University of Alaska-Smithsonian Institution crew worked at five locations in the Baird and Schwatka mountains in northwestern Alaska, conducting an ecological reconnaissance and faunal and floral inventory. Standard methods of observation and collection were used. Camps in the Kobuk drainage were located in the Redstone River valley and at Walker Lake, both on the margin of the taiga. The Noatak valley was represented by one camp each in the lower, middle, and upper reaches of the river, all in tundra. A summary of pre-1963 ornithological work in the region is presented. Significant records of distribution and/or breeding were obtained for the following birds: Podiceps grisegena, Anas platyrhynchos, Aythya valisineria, Histrionicus histrionicus, Melanitta perspicillata, Mergus merganser, Aphrizia virgata, Bartramia longicauda, Actitis macularia, Tringa flavipes, Phalaropus fuficarius, Lobipes lobatus, Larus hyperboreus,Xema sabini, Sayornis saya, Nuttalornis borealis, Eremophilia alpestris, Tachycineta thalassina, Riparia riparia, Petrochelidon pyrrhonota, Phylloscopus borealis, Dendroica petechia, Leucosticte tephrocotis, Zonotrichia atricapilla, Calcarius pictus; and the mammal, Spermophilus undulatus. Good series of Cletihrionomys rutilius (350) and Microtus miurus (147) have been deposited in the University of Alaska Museum. Severe doubt has been raised regarding the validity of the standard three-night trap grid for population estimation under wet conditions in arctic areas

    Relating Biomass and Leaf Area Index to Non-destructive Measurements in Order to Monitor Changes in Arctic Vegetation

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    This paper reports an alternative method for seasonal and long-term monitoring of biomass and the leaf area index (LAI) at Arctic tundra sites. Information related to the historical and projected change in abundance and distribution of biomass and LAI is required to address numerous environmental and resource management issues. Observations of earth from satellites could potentially be used to derive seasonal and long-term changes in biomass and the LAI. To realize this potential, seasonal and long-term ground monitoring data for validation are essential; however, the conventional destructive sampling method for measuring biomass and the LAI does not allow repetitive measurements at the same plots and thus is not suitable for monitoring change over time. Alternative methods, such as sampling nearby similar plots, can be laborious and easily subject to large sampling errors, especially in Arctic tundra sites with low vegetation cover. In this study, we developed a practical method for relating non-destructive measurements (percent cover and mean height) to biomass and the LAI for 13 major Arctic plant groups, or seven plant functional types, on the basis of measurements at 196 plots across Canada’s Arctic tundra ecosystems. Using the method at the plant group level to estimate plot total vascular aboveground biomass, foliage biomass, and LAI, we had r2 = 0.91–0.95 and relative mean absolute error of 25–29%. By this method, one could monitor seasonal and long-term changes in biomass and the LAI through repeated, non-destructive observations of percent cover and mean height at the same permanent plots.Cette communication présente une méthode de rechange en vue de la surveillance saisonnière et à long terme de la biomasse et de l’indice de surface foliaire (LAI) de sites de toundra de l’Arctique. Afin de relever divers enjeux relatifs à la gestion de l’environnement et des ressources, il faut recueillir des données se rapportant au changement historique et projeté en matière d’abondance et de répartition de la biomasse et du LAI. On pourrait éventuellement recourir aux observations de la Terre à partir de satellites afin de déceler les changements saisonniers et à long terme caractérisant la biomasse et le LAI. Pour en arriver là, il est essentiel de disposer de données saisonnières et à long terme au sol à des fins de validation. Cependant, la méthode d’échantillonnage destructeur classique permettant de mesurer la biomasse et le LAI ne permettent pas la prise de mesures répétitives aux mêmes sites et par conséquent, elle ne convient pas à la surveillance du changement qui s’exerce au fil du temps. D’autres méthodes, telles que l’échantillonnage de sites semblables dans les environs, peuvent s’avérer laborieuses et facilement faire l’objet d’importantes erreurs d’échantillonnage, surtout aux sites de toundra de l’Arctique dont la couverture végétale est basse. Dans le cadre de cette étude, nous avons mis au point une méthode pratique pour établir un rapport entre les mesures non destructives (pourcentage de couverture et hauteur moyenne) et la biomasse et le LAI de 13 groupes végétaux importants de l’Arctique, ou sept types végétaux fonctionnels en fonction de la mesure de 196 sites à la grandeur des écosystèmes de toundra de l’Arctique canadien. En nous appuyant sur la méthode des groupes végétaux pour estimer la biomasse vasculaire totale à ciel ouvert des sites, la biomasse foliaire et le LAI, nous avions r2 = 0,91–0,95 et une erreur absolue relative moyenne de 25 à 29%. Au moyen de cette méthode, il serait possible de surveiller les changements saisonniers et à long terme en matière de biomasse et de LAI grâce à des observations répétées et non destructives du pourcentage de la couverture et de la hauteur moyenne aux mêmes sites permanents

    Application of remote sensing data to surveys of the Alaskan environment

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    Coupling of satellite data to resource management problems in Alaska is implemented through feasibility studies of applicability of Landsat data to specific environmental surveys in ecology, agriculture, hydrology, wildlife management, oceanography, geology, etc.; and using the results of these studies to extend the benefits of satellite data applications to the operational needs of mission-oriented agencies of federal, state, and regional governments, as well as private industry. Activities designed to encourage the participation of users in the Landsat program at levels most appropriate to the users' interests are described and include: observation, coordination, and information exchange; training courses and workshops; data exchange; consulting services; data processing services; user participation in University research projects; and university participation in the operational projects of user agencies. Progress in these areas is reported. The effectiveness of this broad-based approach in overcoming the initial apprehensiveness of users is demonstrated

    The Effect of Disturbance on Plant Communities in Tundra Regions of the Soviet Union

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    An Annotated List of Plants Inhabiting Sites of Natural and Anthropogenic Disturbances of Tundra Cover: Southeasternmost Chukchi Peninsula -- B.A. Yurtsev and A.A. Korobkov; An Annotated List of Plants Inhabiting Sites of Natural and Anthropogenic Disturbances of Tundra Cover in Western Taimyr: The Settlement of Kresty -- N.V. Matveyeva; A Study of Plant Communities of Anthropogenic Habitats in the Area of the Vorkuta Industrial Center -- O.A. Druzhinina and Yu. G. Zharkov

    Characterization of muskox habitat in northeastern Alaska

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    Thesis (M.S.) University of Alaska Fairbanks, 1988In northeastern Alaska, muskoxen have been most often found in riparian habitats and proximate uplands. Vegetation was studied in nine adjacent river drainages; six of the drainages are regularly used by muskoxen. Twenty-two vegetation/land cover types were described using aerial photographs, point-intercept sampling, and ocular cover estimates. The proportion of each cover type was estimated for each drainage and compared among drainages by MANOVA. There was no significant difference among non-muskox drainages in the average proportion of cover types. A marginally significant difference was found among muskox drainages. There were no significant differences in the proportions of each vegetation type in non-muskox drainages versus muskox drainages. Five vegetation types associated with high forage quality and availability and low snow accumulation were often used by muskoxen. Four of these five vegetation types typically had <7% cover in the nine drainages and are critical habitat components in northeastern Alaska

    Summit County conservation inventory: volume I, a natural heritage assessment, 1997 final report

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    Prepared for: Summit County Open Space and Trails Dept., Summit County Planning Dept.December 1997.Includes bibliographical references
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