772 research outputs found

    Bioregions and future state visioning: a visually integrative approach to the presentation of information for environmental policy and management.

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    This thesis explores the comparatively new philosophy of bioregionalism to see what it might have to offer the environmental management process. The foundations of bioregional philosophy stretch back into the early part of last century with roots in the thinking of the early 'anarchist geographers' such as Peter Kropotkin. Input also comes from contemporaneous regionalist planners such as Patrick Geddes and Lewis Mumford. However, it was not until the early 1970s that Alan van Newkirk coined the phrase 'Bioregion'. Since then there has been steady growth in bioregional literature that clearly aligns it to ecocentric philosophies that are embraced by social movements like Deep Ecology. However, the most important part of bioregionalism is the bioregions construct. Whatever the philosophical inclinations of bioregionalist authors, the bioregion is presented as an identifiable entity, which is suited to be the basis for the formulation of strategy and planning and it is this that is of interest to this thesis. The basis for the study is the hypothesis that the need for a holistic approach to environmental management and planning requires more than the incremental approaches currently used, if tragedies like Easter Island are not to be repeated on a larger scale. The idea of future state visioning is taken from industry and commerce and given an environmental perspective to provide the visionary dimension required by such a holistic process. However, a visionary process is best served by a visualization tool, particularly where non-expert, community participation is deemed essential. The process of mapping bioregions is just such a tool. The proposal that bioregional mapping is suitable as a tool requires that bioregions, as a construct, are demonstrable entities, as claimed by the literature. Tberefore, a mapping exercise that allowed the testing of this principle was undertaken for Scotland as the test area. A methodology was developed, using a Geographical Information System to assist in the mapping and analysis. Statistical analysis of the resultant theoretical bioregional model showed that the bioregions had good agreement with other methods of dividing Scotland into regions. They also showed better agreement with these other regionalisations than politically defined regions. The notion that watersheds can be substituted for bioregions was rejected. Therefore, it was shown that bioregions are demonstrable entities,albeit sensitive to scale. The bioregions produced from first principles were compared to an independent qualitatively developed model, The results of this comparison reinforces a suggestion that a 'science of quantities' needs to be tempered by a 'science of qualities' when stakeholder participation and interpretation is important. The dramatic story of the social and environmental collapse of Easter Island is a metaphor for the situation facing the Earth, as a whole on the one hand, and to introduce the arguments of sustainability and regionality on the other. Easter Island is isolated, with almost no external inputs, like the Earth, but on a different scale. However, it is also a part of the Earth. From many sources, there is agreement that the natural environment of the Earth is under threat, not just on the local scale but on a global scale as well. Bioregions are proposed as a holistic way of mapping the environment to inform the future state visioning process, which is offered as a tool at the level of strategic management. Bioregional mapping and environmental future state visioning were proposed as vehicles for stakeholder participation and the recognition of cultural factors in environmental management and planning. Future work should include investigating future state visioning solutions to more localised and community focused environmental management problems. Scotland, as the subject for analysis, provides a manageable compromise between the extreme isolation and singularity of Easter Island and the multiplicity of the regions of the world. Scotland is an area that has good data on its various forms of regionality, including cultural and biogeographic regions

    High resolution spatial variability in spring snowmelt for an Arctic shrub-tundra watershed

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    Arctic tundra environments are characterized by spatially heterogeneous end-of-winter snow cover because of high winds that erode, transport and deposit snow over the winter. This spatially variable end-of-winter snow cover subsequently influences the spatial and temporal variability of snowmelt and results in a patchy snowcover over the melt period. Documenting changes in both snow cover area (SCA) and snow water equivalent (SWE) during the spring melt is essential for understanding hydrological systems, but the lack of high-resolution SCA and SWE datasets that accurately capture micro-scale changes are not commonly available, and do not exist for the Canadian Arctic. This study applies high-resolution remote sensing measurements of SCA and SWE using a fixed-wing Unmanned Aerial System (UAS) to document snowcover changes over the snowmelt period for an Arctic tundra headwater catchment. Repeat measurements of SWE and SCA were obtained for four dominant land cover types (tundra, short shrub, tall shrub, and topographic drift) to provide observations of spatially distributed snowmelt patterns and basin-wide declines in SWE. High-resolution analysis of snowcover conditions over the melt reveal a strong relationship between land cover type, snow distribution, and snow ablation rates whereby shallow snowpacks found in tundra and short shrub regions feature rapid declines in SWE and SCA and became snow-free approximately 10 days earlier than deeper snowpacks. In contrast, tall shrub patches and topographic drift regions were characterized by large initial SWE values and featured a slow decline in SCA. Analysis of basin-wide declines in SCA and SWE reveal three distinct melt phases characterized by 1) low melt rates across a large area resulting in a minor change in SCA, but a very large decline in SWE with, 2) high melt rates resulting in drastic declines in both SCA and SWE, and 3) low melt rates over a small portion of the basin, resulting in little change to either SCA or SWE. The ability to capture high-resolution spatio-temporal changes to tundra snow cover furthers our understanding of the relative importance of various land cover types on the snowmelt timing and amount of runoff available to the hydrological system during the spring freshet

    A graph-based mathematical morphology reader

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    This survey paper aims at providing a "literary" anthology of mathematical morphology on graphs. It describes in the English language many ideas stemming from a large number of different papers, hence providing a unified view of an active and diverse field of research

    Analyses of the Watershed Transform

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    International audienceIn the framework of mathematical morphology, watershed transform (WT) represents a key step in image segmentation procedure. In this paper, we present a thorough analysis of some existing watershed approaches in the discrete case: WT based on flooding, WT based on path-cost minimization, watershed based on topology preservation, WT based on local condition and WT based on minimum spanning forest. For each approach, we present detailed description of processing procedure followed by mathematical foundations and algorithm of reference. Recent publications based on some approaches are also presented and discussed. Our study concludes with a classification of different watershed transform algorithms according to solution uniqueness, topology preservation, prerequisites minima computing and linearity

    Fire effects on aquatic ecosystems: an assessment of the current state of science

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    Fire is a prevalent feature of many landscapes and has numerous and complex effects on geological, hydrological, ecological, and economic systems. In some regions, the frequency and intensity of wildfire have increased in recent years and are projected to escalate with predicted climatic and landuse changes. In addition, prescribed burns continue to be used in many parts of the world to clear vegetation for development projects, encourage desired vegetation, and reduce fuel loads. Given the prevalence of fire on the landscape, authors of papers in this special series examine the complexities of fire as a disturbance shaping freshwater ecosystems and highlight the state of the science. These papers cover key aspects of fire effects that range from vegetation loss and recovery in watersheds to effects on hydrology and water quality with consequences for communities (from algae to fish), food webs, and ecosystem processes (e.g., organic matter subsidies, nutrient cycling) across a range of scales. The results presented in this special series of articles expand our knowledge of fire effects in different biomes, water bodies, and geographic regions, encompassing aquatic population, community, and ecosystem responses. In this overview, we summarize each paper and emphasize its contributions to knowledge on fire ecology and freshwater ecosystems. This overview concludes with a list of 7 research foci that are needed to further our knowledge of fire effects on aquatic ecosystems, including research on: 1) additional biomes and geographic regions; 2) additional habitats, including wetlands and lacustrine ecosystems; 3) different fire severities, sizes, and spatial configurations; and 4) additional response variables (e.g., ecosystem processes) 5) over long (>5 y) time scales 6) with more rigorous study designs and data analyses, and 7) consideration of the effects of fire management practices and policies on aquatic ecosystems

    An open and extensible framework for spatially explicit land use change modelling in R: the lulccR package (0.1.0)

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    Land use change has important consequences for biodiversity and the sustainability of ecosystem services, as well as for global environmental change. Spatially explicit land use change models improve our understanding of the processes driving change and make predictions about the quantity and location of future and past change. Here we present the lulccR package, an object-oriented framework for land use change modelling written in the R programming language. The contribution of the work is to resolve the following limitations associated with the current land use change modelling paradigm: (1) the source code for model implementations is frequently unavailable, severely compromising the reproducibility of scientific results and making it impossible for members of the community to improve or adapt models for their own purposes; (2) ensemble experiments to capture model structural uncertainty are difficult because of fundamental differences between implementations of different models; (3) different aspects of the modelling procedure must be performed in different environments because existing applications usually only perform the spatial allocation of change. The package includes a stochastic ordered allocation procedure as well as an implementation of the widely used CLUE-S algorithm. We demonstrate its functionality by simulating land use change at the Plum Island Ecosystems site, using a dataset included with the package. It is envisaged that lulccR will enable future model development and comparison within an open environment

    Sustainable intensification of agriculture for human prosperity and global sustainability

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    There is an ongoing debate on what constitutes sustainable intensification of agriculture (SIA). In this paper, we propose that a paradigm for sustainable intensification can be defined and translated into an operational framework for agricultural development. We argue that this paradigm must now be defined—at all scales—in the context of rapidly rising global environmental changes in the Anthropocene, while focusing on eradicating poverty and hunger and contributing to human wellbeing. The criteria and approach we propose, for a paradigm shift towards sustainable intensification of agriculture, integrates the dual and interdependent goals of using sustainable practices to meet rising human needs while contributing to resilience and sustainability of landscapes, the biosphere, and the Earth system. Both of these, in turn, are required to sustain the future viability of agriculture. This paradigm shift aims at repositioning world agriculture from its current role as the world’s single largest driver of global environmental change, to becoming a key contributor of a global transition to a sustainable world within a safe operating space on Earth

    Control by Vegetation Disturbance on Gully Rejuvenation Following Wildfire

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    Gully rejuvenation (GR) following wildfire influences landform evolution and generates flooding and debris that alters aquatic habitat and threatens human activities. Fire severity, defined as the degree of vegetation loss by wildfire, is a hypothesized control on this erosion response. I investigated three related aspects of the relationship between fire severity and GR: The capacity of vegetation disturbance to explain the occurrence or non-occurrence of GR; the spatial structure of burn mosaics relative to post-fire erosion; and the relationship between fire severity and threshold conditions required for channel initiation. I surveyed 269 burned catchments and mapped 111 cases of GR across sites in Montana and Idaho. I created the Vegetation Disturbance Index (VDI) derived from LANDSAT images to quantify fire severity and implemented geospatial and statistical analysis to quantify relationships between VDI and post-fire erosion response. Vegetation disturbance strongly explained GR with additional influences from upslope geometry and pre-fire shrub cover. As fire severity increased, the percent of the catchment area covered by continuous patches of high severity burn increased non-linearly. Trends in patch structure defined a threshold of fire severity after which the probability of GR was strongly correlated with the development of large, continuous severely burned patches. Fire severity systematically influenced the relationship between source area and steepness. Threshold conditions for channel initiation, specifically source area steepness and curvature, decreased as vegetation disturbance increased. These results provide inferential evidence that vegetation disturbance exerts first-order controls over post-fire erosion processes. The results of the patch-pattern analysis suggest that progressive loss of vegetation due to wildfire leads to critical thresholds of hydrologic connectivity after which runoff and erosion accelerate. The source area analysis suggests that forces of convergent flow are not fully expressed until a significant proportion of vegetation has been consumed such that flow resistance is minimized. The VDI as a continuous metric of vegetation disturbance may contribute to improved quantitative analysis of landform evolution relative to vegetation disturbance, ecological effects of fire, and ecosystem response to climate change. The assessment methodology outlined herein provides a first step towards a systematic quantification of the potential for GR following wildfire
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