11 resultados para Nahuel Huapi National Park

em Digital Commons - Michigan Tech


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A post classification change detection technique based on a hybrid classification approach (unsupervised and supervised) was applied to Landsat Thematic Mapper (TM), Landsat Enhanced Thematic Plus (ETM+), and ASTER images acquired in 1987, 2000 and 2004 respectively to map land use/cover changes in the Pic Macaya National Park in the southern region of Haiti. Each image was classified individually into six land use/cover classes: built-up, agriculture, herbaceous, open pine forest, mixed forest, and barren land using unsupervised ISODATA and maximum likelihood supervised classifiers with the aid of field collected ground truth data collected in the field. Ground truth information, collected in the field in December 2007, and including equalized stratified random points which were visual interpreted were used to assess the accuracy of the classification results. The overall accuracy of the land classification for each image was respectively: 1987 (82%), 2000 (82%), 2004 (87%). A post classification change detection technique was used to produce change images for 1987 to 2000, 1987 to 2004, and 2000 to 2004. It was found that significant changes in the land use/cover occurred over the 17- year period. The results showed increases in built up (from 10% to 17%) and herbaceous (from 5% to 14%) areas between 1987 and 2004. The increase of herbaceous was mostly caused by the abandonment of exhausted agriculture lands. At the same time, open pine forest and mixed forest areas lost (75%) and (83%) of their area to other land use/cover types. Open pine forest (from 20% to 14%) and mixed forest (from18 to 12%) were transformed into agriculture area or barren land. This study illustrated the continuing deforestation, land degradation and soil erosion in the region, which in turn is leading to decrease in vegetative cover. The study also showed the importance of Remote Sensing (RS) and Geographic Information System (GIS) technologies to estimate timely changes in the land use/cover, and to evaluate their causes in order to design an ecological based management plan for the park.

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Landscape structure and heterogeneity play a potentially important, but little understood role in predator-prey interactions and behaviourally-mediated habitat selection. For example, habitat complexity may either reduce or enhance the efficiency of a predator's efforts to search, track, capture, kill and consume prey. For prey, structural heterogeneity may affect predator detection, avoidance and defense, escape tactics, and the ability to exploit refuges. This study, investigates whether and how vegetation and topographic structure influence the spatial patterns and distribution of moose (Alces alces) mortality due to predation and malnutrition at the local and landscape levels on Isle Royale National Park. 230 locations where wolves (Canis lupus) killed moose during the winters between 2002 and 2010, and 182 moose starvation death sites for the period 1996-2010, were selected from the extensive Isle Royale Wolf-Moose Project carcass database. A variety of LiDAR-derived metrics were generated and used in an algorithm model (Random Forest) to identify, characterize, and classify three-dimensional variables significant to each of the mortality classes. Furthermore, spatial models to predict and assess the likelihood at the landscape scale of moose mortality were developed. This research found that the patterns of moose mortality by predation and malnutrition across the landscape are non-random, have a high degree of spatial variability, and that both mechanisms operate in contexts of comparable physiographic and vegetation structure. Wolf winter hunting locations on Isle Royale are more likely to be a result of its prey habitat selection, although they seem to prioritize the overall areas with higher moose density in the winter. Furthermore, the findings suggest that the distribution of moose mortality by predation is habitat-specific to moose, and not to wolves. In addition, moose sex, age, and health condition also affect mortality site selection, as revealed by subtle differences between sites in vegetation heights, vegetation density, and topography. Vegetation density in particular appears to differentiate mortality locations for distinct classes of moose. The results also emphasize the significance of fine-scale landscape and habitat features when addressing predator-prey interactions. These finer scale findings would be easily missed if analyses were limited to the broader landscape scale alone.

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This dissertation examines the genesis and development of Keweenaw National Historical Park in Michigan's Upper Peninsula. After the decline of a once-thriving copper mining industry, local residents pursued the creation of a national park as a way to encourage economic development, revitalize their community, and preserve their historic resources. Although they were ultimately successful in creating a national park, the park that was established was not the park that they envisioned. Over the next twenty years, the National Park Service, the park's federal Advisory Commission, and the communities on the Keweenaw Peninsula struggled to align unrealistic expectations with the actual capabilities and limitations of the park. The first chapter of this dissertation includes a short history of the decline of the copper industry in and around the village of Calumet, Michigan. This chapter also includes a discussion about the techniques and challenges of preserving and interpreting industrial heritage. Chapters 2 and 3 cover the events from the initial park proposal, to the expansion of the original idea, to the establishment of the park. Chapter 4 includes an examination of the enabling legislation and a discussion about the opportunities and challenges it provided. Chapters 5 through 8 cover the tenure of each of the four NPS superintendents as they navigated the complexities presented by a park model that was part partnership park and part traditional national park. Chapter 9 includes some key lessons, an assessment of the park's success, and some considerations for the future. In particular, Chapter 9 argues for an increased focus on the partnership aspects of the park, a reduction in the perceived scope of responsibilities, and a renewed effort to rally the existing partners in pursuing additional philanthropic support for the overall park.

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The Finnish American Heritage Center at Finlandia University recently installed three exhibits. They include a photographic exhibit titled “Rural Reflections: Finnish American Buildings and Landscapes in Michigan’s Copper Country”; a historic photography exhibit named “People, Place and Time: Michigan’s Copper Country Through the Lens of J.W. Nara”; and a pair of lithographs acquired by the National Park Service which were on either side of the Italian Hall stage the night of the infamous Christmas Eve tragedy 100 years ago. The “Rural Reflections” exhibit documents the built environment that Finnish immigrants and their descendants created in Michigan's Copper Country from the 1880s through the 1930s. Although much of this heritage has been lost with the passage of time, the district yet holds one of the largest concentrations of rural Finnish buildings and cultural landscapes in North America. The Nara exhibit, funded in part by descendants Robert and Ruth Nara of Bootjack Michigan, works from historical photographs held at the Michigan Tech Archives. Interpretive panels highlight the people, places, and times that J.W. Nara experienced during his lifetime and include material on urban life, farming, and the 1913 Michigan copper miners’ strike. The lithographs are a recent and unique acquisition for the Keweenaw National Historical Park, and will be on protected display at the FAHC. One of the panels shows the Italian royal family and was produced in 1908, while the other, produced in 1905, is of the five founders of the modern Italian state. For more information about the exhibits at the Finnish American Heritage Center, call (906) 487-7302.

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The Finnish American Heritage Center at Finlandia University recently installed three exhibits. They include a photographic exhibit titled “Rural Reflections: Finnish American Buildings and Landscapes in Michigan’s Copper Country”; a historic photography exhibit named “People, Place and Time: Michigan’s Copper Country Through the Lens of J.W. Nara”; and a pair of lithographs acquired by the National Park Service which were on either side of the Italian Hall stage the night of the infamous Christmas Eve tragedy 100 years ago. The “Rural Reflections” exhibit documents the built environment that Finnish immigrants and their descendants created in Michigan's Copper Country from the 1880s through the 1930s. Although much of this heritage has been lost with the passage of time, the district yet holds one of the largest concentrations of rural Finnish buildings and cultural landscapes in North America. The Nara exhibit, funded in part by descendants Robert and Ruth Nara of Bootjack Michigan, works from historical photographs held at the Michigan Tech Archives. Interpretive panels highlight the people, places, and times that J.W. Nara experienced during his lifetime and include material on urban life, farming, and the 1913 Michigan copper miners’ strike. The lithographs are a recent and unique acquisition for the Keweenaw National Historical Park, and will be on protected display at the FAHC. One of the panels shows the Italian royal family and was produced in 1908, while the other, produced in 1905, is of the five founders of the modern Italian state. For more information about the exhibits at the Finnish American Heritage Center, call (906) 487-7302.

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The Finnish American Heritage Center at Finlandia University recently installed three exhibits. They include a photographic exhibit titled “Rural Reflections: Finnish American Buildings and Landscapes in Michigan’s Copper Country”; a historic photography exhibit named “People, Place and Time: Michigan’s Copper Country Through the Lens of J.W. Nara”; and a pair of lithographs acquired by the National Park Service which were on either side of the Italian Hall stage the night of the infamous Christmas Eve tragedy 100 years ago. The “Rural Reflections” exhibit documents the built environment that Finnish immigrants and their descendants created in Michigan's Copper Country from the 1880s through the 1930s. Although much of this heritage has been lost with the passage of time, the district yet holds one of the largest concentrations of rural Finnish buildings and cultural landscapes in North America. The Nara exhibit, funded in part by descendants Robert and Ruth Nara of Bootjack Michigan, works from historical photographs held at the Michigan Tech Archives. Interpretive panels highlight the people, places, and times that J.W. Nara experienced during his lifetime and include material on urban life, farming, and the 1913 Michigan copper miners’ strike. The lithographs are a recent and unique acquisition for the Keweenaw National Historical Park, and will be on protected display at the FAHC. One of the panels shows the Italian royal family and was produced in 1908, while the other, produced in 1905, is of the five founders of the modern Italian state. For more information about the exhibits at the Finnish American Heritage Center, call (906) 487-7302.

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Habitat selection has been one of the main research topics in ecology for decades. Nevertheless, many aspects of habitat selection still need to be explored. In particular, previous studies have overlooked the importance of temporal variation in habitat selection and the value of including data on reproductive success in order to describe the best quality habitat for a species. We used data collected from radiocollared wolves in Yellowstone National Park (USA), between 1996 and 2008, to describe wolf habitat selection. In particular, we aimed to identify i) seasonal differences in wolf habitat selection, ii) factors influencing interannual variation in habitat selection, and iii) the effect of habitat selection on wolf reproductive success. We used probability density functions to describe wolf habitat use and habitat coverages to represent the habitat available to wolves. We used regression analysis to connect habitat use with habitat characteristics and habitat selection with reproductive success. Our most relevant result was discovering strong interannual variability in wolf habitat selection. This variability was in part explained by pack identity and differences in litter size and leadership of a pack between two years (summer) and in pack size and precipitation (winter). We also detected some seasonal differences. Wolves selected open habitats, intermediate elevations, intermediate distances from roads, and avoided steep slopes in late winter. They selected areas close to roads and avoided steep slopes in summer. In early winter, wolves selected wetlands, herbaceous and shrub vegetation types, and areas at intermediate elevation and distance from roads. Surprisingly, the habitat characteristics selected by wolves were not useful in predicting reproductive success. We hypothesize that interannual variability in wolf habitat selection may be too strong to detect effects on reproductive success. Moreover, prey availability and competitor pressure may also have an influence on wolf reproductive success, which we did not assess. This project demonstrated how important temporal variation is in shaping patterns of habitat selection. We still believe in the value of running long-term studies, but the effect of temporal variation should always be taken into account.

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Invasive exotic plants have altered natural ecosystems across much of North America. In the Midwest, the presence of invasive plants is increasing rapidly, causing changes in ecosystem patterns and processes. Early detection has become a key component in invasive plant management and in the detection of ecosystem change. Risk assessment through predictive modeling has been a useful resource for monitoring and assisting with treatment decisions for invasive plants. Predictive models were developed to assist with early detection of ten target invasive plants in the Great Lakes Network of the National Park Service and for garlic mustard throughout the Upper Peninsula of Michigan. These multi-criteria risk models utilize geographic information system (GIS) data to predict the areas at highest risk for three phases of invasion: introduction, establishment, and spread. An accuracy assessment of the models for the ten target plants in the Great Lakes Network showed an average overall accuracy of 86.3%. The model developed for garlic mustard in the Upper Peninsula resulted in an accuracy of 99.0%. Used as one of many resources, the risk maps created from the model outputs will assist with the detection of ecosystem change, the monitoring of plant invasions, and the management of invasive plants through prioritized control efforts.

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Herbivory requires animals to manage intake of toxic phytochemicals. Detoxification and excretion of these chemicals prevents toxicity, but is energetically expensive. I investigated the relationship between investment in detoxification and nutritional condition for moose on Isle Royale National Park (Alces alces) during winter, using urinary indices from urine samples collected in snow. The ratio of urinary urea nitrogen:creatinine is an indicator of nutritional condition, and the ratio of glucuronic acid:creatinine is an indicator of investment in detoxification. Nutritional condition declined with greater investment in detoxification. An alternative means of managing defensive chemical intake is to diversify the diet. Microhistological analysis of fecal pellets determined diet composition. Diet diversity was weakly associated with improved nutritional condition. However, the strongest predictors of nutritional condition were winter severity and proportion of balsam fir in the diet (a dominant food for moose in this ecosystem).

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Ungulates are important components of a variety of ecosystems worldwide. This dissertation integrates aspects of ungulate and forest ecology to increase our understanding of how they work together in ways that are of interest to natural resource managers, educators, and those who are simply curious about nature. Although animal ecology and ecosystem ecology are often studied separately, one of the general goals of this dissertation is to examine how they interact across spatial and temporal scales. Forest ecosystems are heterogeneous across a range of scales. Spatial and temporal habitat use patterns of forest ungulates tend to be congregated in patches where food and/or cover are readily available. Ungulates interact with ecosystem processes by selectively foraging on plants and excreting waste products in concentrated patches. Positive feedbacks may develop where these activities increase the value of habitat through soil fertilization or the alteration of plant chemistry and architecture. Heterogeneity in ecosystem processes and plant community structure, observed at both stand and local scales, may be the integrated outcome of feedbacks between ungulate behavior and abiotic resource gradients. The first chapter of this dissertation briefly discusses pertinent background information on ungulate ecology, with a focus on white-tailed deer (Odocoileus virginianus) in the Upper Great Lakes region and moose (Alces acles) in Isle Royale National Park, Michigan, USA. The second chapter demonstrates why ecological context is important for studying ungulate ecology in forest ecosystems. Excluding deer from eastern hemlock (Tsuga canadensis) stands, which deer use primarily as winter cover, resulted in less spatial complexity in soil reactive nitrogen and greater complexity in diffuse light compared to unfenced stands. The spatial patterning of herbaceous-layer cover was more similar to nitrogen where deer were present, and was a combination of nitrogen and light within deer exclosures. This relationship depends on the seasonal timing of deer habitat use because deer fertilize the soil during winter, but leave during the growing season. The third chapter draws upon an eight-year, 39-stand data set of deer fecal pellet counts in hemlock stands to estimate the amount of nitrogen that deer are depositing in hemlock stands each winter. In stands of high winter deer use, deer-excreted nitrogen inputs consistently exceeded those of atmospheric deposition at the stand scale. At the neighborhood scale, deer-excreted nitrogen was often in excess of atmospheric deposition due to the patchy distribution of deer habitat use. Spatial patterns in habitat use were consistent over the eight-year study at both stand and neighborhood scales. The fourth chapter explores how foraging selectivity by moose interacts with an abiotic resource gradient to influence forest structure and composition. Soil depth on Isle Royale varies from east to west according to glacial history. Fir saplings growing in deeper soils on the west side are generally more palatable forage for moose (lower foliar C:N) than those growing in shallower soils on the east side. Therefore, saplings growing in better conditions are less likely to reach the canopy due to moose browsing, and fir is a smaller overstory component on the west side. Lastly, chapter five focuses on issues surrounding eastern hemlock regeneration failure, which is a habitat type that is important to many wildlife species. Increasing hemlock on the landscape is complicated by several factors including disturbance regime and climate change, in addition to the influence of deer.

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Within the Yellowstone National Park, Wyoming, the silicic Yellowstone volcanic field is one of the most active volcanic systems all over the world. Although the last rhyolite eruption occurred around 70,000 years ago, Yellowstone is still believed to be volcanically active, due to high hydrothermal and seismic activity. The earthquake data used in this study cover the period of time between 1988 and 2010. Earthquake relocations and a set of 369 well-constrained, double-couple, focal mechanism solutions were computed. Events were grouped according to location and time to investigate trends in faulting. The majority of the events has oblique, normal-faulting solutions. The overall direction of extension throughout the 0.64 Ma Yellowstone caldera looks nearly ENE, consistently with the direction of alignments of volcanic vents within the caldera, but detailed study revealed spatial and temporal variations. Stress-field solutions for different areas and time periods were calculated from earthquake focal mechanism inversion. A well-resolved rotation of σ3 was found, from NNE-SSW near the Hebgen Lake fault zone, to ENE-WSW near Norris Junction. In particular, the σ3 direction changed throughout the years in the Norris Junction area, from being ENE-WSW, as calculated in the study by Waite and Smith (2004), to NNE-SSW, while the other σ3 directions are mostly unchanged over time. The Yellowstone caldera was subject to periods of net uplift and subsidence over the past century, explained in previous studies as caused by expanding or contracting sills, at different depths. Based on the models used to explain these deformation periods, we investigated the relationship between variability in aseismic deformation and seismic activity and faulting styles. Focal mechanisms and P and T axes were divided into temporal and depth intervals, in order to identify spatial or temporal trends in deformation. The presence of “chocolate tablet” structures, with composite dilational faults, was identified in many stages of the deformation history both in the Norris Geyser Basin area and inside the caldera. Strike-slip component movement was found in a depth interval below a contracting sill, indicating the movement of magma towards the caldera.