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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of mathematical biology 59 (1997), S. 1013-1028 
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1572-9761
    Keywords: index ; dominance ; contagion ; fractal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Landscape ecology deals with the patterning of ecosystems in space. Methods are needed to quantify aspects of spatial pattern that can be correlated with ecological processes. The present paper develops three indices of pattern derived from information theory and fractal geometry. Using digitized maps, the indices are calculated for 94 quadrangles covering most of the eastern United States. The indices are shown to be reasonably independent of each other and to capture major features of landscape pattern. One of the indices, the fractal dimension, is shown to be correlated with the degree of human manipulation of the landscape.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-9761
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fifty-five metrics of landscape pattern and structure were calculated for 85 maps of land use and land cover. A multivariate factor analysis was used to identify the common axes (or dimensions) of pattern and structure which were measured by a reduced set of 26 metrics. The first six factors explained about 87% of the variation in the 26 landscape metrics. These factors were interpreted as composite measures of average patch compaction, overall image texture, average patch shape, patch perimeter-area scaling, number of attribute classes, and large-patch density-area scaling. We suggest that these factors can be represented in a simpler way by six univariate metrics - average perimeter-area ratio, contagion, standardized patch shape, patch perimeter-area scaling, number of attribute classes, and large-patch density-area scaling.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9761
    Keywords: Yellowstone National Park ; foraging ecology ; foraging hierarchy ; snow ; landscape ecology ; ungulates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between fine-scale spatial patterns of forage abundance and the feeding patterns of large ungulates is not well known. We compared these patterns for areas grazed in winter by elk and bison in a sagebrush-grassland landscape in northern Yellowstone National Park. At a fine scale, the spatial distribution of mapped feeding stations in 30 m × 30 m sites was found to be random where there were no large patches devoid of vegetation. In areas similar to the mapped sites, the underlying spatial distribution pattern of biomass was also determined to be random. At a broad scale, forage biomass differed among communities across the northern range but forage quality did not. These results suggest that ungulates are feeding randomly within forage patches (fine scale) but may select feeding sites based upon forage abundance at broader, landscape scales. Contrary to what has been suggested in other systems, ungulates were not ‘overmatching’ at finer scales.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Landscape ecology 2 (1988), S. 63-69 
    ISSN: 1572-9761
    Keywords: percolation theory ; probability theory ; landscape ecology ; scale ; pattern
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial patterning of resources constrains the movement of consumers on the landscape. Percolation theory predicts that an organism can move freely if its critical resource or habitat occupies 59.28% of the landscape. Sparse resources require an organism to operate on larger resource utilization scales. Multiple critical resources necessitate larger scales, while substitutable resources ease the scale requirements. Contagious spatial patterns require larger scales to permit movement between resource clusters. The study indicates a strong link between spatial pattern and ecological processes on a landscape.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-9761
    Keywords: scale ; landscape ; critical threshold ; extrapolate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A simple model of animal movement on random and patterned landscapes was used to explore the problems of extrapolating information across a range of spatial scales. Simulation results indicate that simple relation- ships between pattern and process will produce a variety of scale-dependent effects. These theoretical studies can be used to design experiments for determining the nature of scale-dependent processes and to estimate parameters for extrapolating information across scales.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Landscape ecology 3 (1989), S. 193-205 
    ISSN: 1572-9761
    Keywords: hierarchy theory ; nonequilibrium ; thermodynamics ; catastrophe theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Landscapes are complex ecological systems that operate over broad spatiotemporal scales. Hierarchy theory conceptualizes such systems as composed of relatively isolated levels, each operating at a distinct time and space scale. This paper explores some basic properties of scaled systems with a view toward taking advantage of the scaled structure in predicting system dynamics. Three basic properties are explored: (1) hierarchical structuring, (2) disequilibrium, and (3) metastability. These three properties lead to three conclusions about complex ecological systems. First, predictions about landscape dynamics can often be based on constraints that directly result from scaled structure. Biotic potential and environmental limits form a constraint envelope, analogous to a niche hypervolume, within which the landscape system must operate. Second, within the constraint envelope, thermodynamic and other limiting factors may produce attractors toward which individual landscapes will tend to move. Third, because of changes in biotic potential and environmental conditions, both the constraint envelope and the local attractors change through time. Changes in the constraint structure may involve critical thresholds that result in radical changes in the state of the system. An attempt is made to define measurements to predict whether a specific landscape is approaching a critical threshold.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1572-9761
    Keywords: hierarchy ; scale ; vegetation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Vegetation transect data from three locations were analyzed to determine if multiple scales of pattern could be detected. The sites included a semiarid grassland in New Mexico, a series of calcareous openings in a deciduous forest in Tennessee, and a shrub-steppe system in Washington. The data were explored with four statistical techniques. A scale of pattern was accepted if detected by more than one analytical method or located by a single method in multiple taxa. The analyses indicated 3–5 scales of pattern on all three sites, as predicted by Hierarchy Theory.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1572-9761
    Keywords: grain ; extent ; index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Remotely sensed data for Southeastern United States (Standard Federal Region 4) are used to examine the scale problems involved in reporting landscape pattern for a large, heterogeneous region. Frequency distributions of landscape indices illustrate problems associated with the grain or resolution of the data. Grain should be 2 to 5 times smaller than the spatial features of interest. The analyses also reveal that the indices are sensitive to the calculation scale,i.e., the unit area or extent over which the index is computed. This “sample area” must be 2 to 5 times larger than landscape patches to avoid bias in calculating the indices.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1009
    Keywords: KEY WORDS: Cluster analysis; Cumulative impact; Geographic information systems; Landscape ecology; Remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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