LANDSCAPE ECOLOGY SREM 3011 LECTURE 9 Dr Brendan Mackey Department of Geography The Australian National University
LANDSCAPE ECOLOGY SREM 3011 LECTURE 9 Dr Brendan Mackey Department of Geography The Australian National University
Scale provides concepts and tools for ntegrating the effects of environmental processes on the occupancy of landscapes by plants and animals If we do not think about scale, then we risk being captive of scale imposed by human senses
• Scale provides concepts and tools for integrating the effects of environmental processes on the occupancy of landscapes by plants and animals • If we do not think about scale, then we risk being captive of scale imposed by human senses
Ecology is a matter of primary human experience
Ecology is a matter of primary human experience
Landscape texture horizontal a'verticals Scale at which structures occur in the landscape Structures components of a system At 'landscape to regional"scales", vegetation is a major component of"structure species composition, canopy height, vertical organization, leaf physiognomy particularly important with respect to the occupancy of landscapes by animals Texture= measure of the complexity of landscape structure E complexity in the spatial configuration of vegetation(eg. patches)
• Landscape texture ‘horizontal’ ‘vertical’ Scale at which structures occur in the landscape Structures = components of a system At ‘landscape’ to ‘regional’ “scales”, vegetation is a major component of “structure” : species composition, canopy height, vertical organization, leaf physiognomy : particularly important with respect to the occupancy of landscapes by animals Texture = measure of the complexity of landscape structure = complexity in the spatial configuration of vegetation (eg. ‘patches’)
Fine texture many, small patches with convoluted perimeters Coarse texture a few large patches with simple perimeters Vertical structure of vegetation fine/coarse textured Fractal dimension(Horizontal texture) a measure of landscape complexity OR landscape texture based on measurement of length of boundaries of entities forming patterns (1)Length of measuring unit or ' segment (2) Total length of perimeter
• Fine texture = many, small patches with convoluted perimeters • Coarse texture = a few large patches with simple perimeters • Vertical structure of vegetation fine/coarse textured Fractal dimension (Horizontal texture) - a measure of landscape complexity landscape texture - based on measurement of length of boundaries of entities forming patterns - (1) Length of measuring unit or ‘segment’ (2) Total length of perimeter OR
Maps of Britain capture more detail as the length segments used for the outline are shortened. With the longest straight line segments, Britain appears only as a triangle As the straight segments of the outline are made shorter, more and more detail emerges while the length of the coastline increases. For infinitely small straight line segments, the coastline of Britain is infinitely long
Maps of Britain capture more detail as the length segments used for the outline are shortened. With the longest straight line segments, Britain appears only as a triangle. As the straight segments of the outline are made shorter, more and more detail emerges while the length of the coastline increases. For infinitely small straight line segments, the coastline of Britain is infinitely long
The more complicated is the outline of a shape, the greater the total perimeter will ncrease as the line segments used to outline it are made shorter. The upper shape a is simple and so has a small ratio estimated perimeters with long and short estimator seg ments(1.1041). The lower shape is complicated so revealing a greater increase in peri- meter with short estimator segments to yield a larger ratio(1.1611) A. Ratio 1:1.041 B. Ratio 1:1.611
The more complicated is the outline of a shape, the greater the total perimeter will increase as the line segments used to outline it are made shorter. The upper shape A is simple and so has a small ratio estimated perimeters with long and short estimator segments (1.1041). The lower shape is complicated so revealing a greater increase in perimeter with short estimator segments to yield a larger ratio (1.1611)
If a log-log plot of the length of the estimators and the length of the total perimeter is a straight line, then the structure is fractal Complex Form 岩 瓦 Slope= 1-dimension Log length of estimator segment Simple form Slope =2-dimension Log length of estimator segment
If a log-log plot of the length of the estimators and the length of the total perimeter is a straight line, then the structure is fractal
In the Koch diagram, straight line segments are divided into four segments with a point emerging in the middle of each straight line. Subsequent straight lines of shorter lengths can then be further divided into lines with a point in the middle. This system is self similar, in that successively finer-grained patterns follow smaller scale versions of the original pattern The fractal dimension of a Koch diagram is 4/3 Self-similar pattern and so or
In the Koch diagram, straight line segments are divided into four segments with a point emerging in the middle of each straight line. Subsequent straight lines of shorter lengths can then be further divided into lines with a point in the middle. This system is selfsimilar, in that successively finer-grained patterns follow smaller scale versions of the original pattern. The fractal dimension of a Koch diagram is 4/3. Self-similar pattern
If the degree of complexity of the outline of a form is different at different scales, then the log-log plot of line segment against perimeter will bend at the scale at which the comple- xity of the pattern changes. At that point the fractal dimension itself changes. The outlines are merely to show simple and complex patterns at different scales the differently scaled patterns are so specifically scaled that the shapes are not strictly fractal, but are to illus trate the point that large and small scale patterns can readily exhibit different degrees of complexity Small scale simple Small scale complex large scale complex large scale simple WSfO compiex imple compler E△≌8 6D Log estimator segments Log estimator segments
If the degree of complexity of the outline of a form is different at different scales, then the log-log plot of line segment against perimeter will bend at the scale at which the complexity of the pattern changes. At that point the fractal dimension itself changes. The outlines are merely to show simple and complex patterns at different scales; the differently scaled patterns are so specifically scaled that the shapes are not strictly fractal, but are to illustrate the point that large and small scale patterns can readily exhibit different degrees of complexity