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Landscape mosaic
Patch types
Desert vegetation
Desert vegetation
Esker 1
Esker 2
Kettle
Mesa Verde fire map
Mesa Verde satellite
Compare
Fire patch
Animals trampling
Wind patterns
mudslides
Alluvial fan
Alluvial Fan
Strip mining
Human pattern
plantation
Orchards
Logging
Logging
PATCH SHAPE
Patch shape determines the distance between the patch’s
edge and the patch’s habitat interior, and the core area
• Compact forms are effective in protecting their internal
resources against negative effects of the surroundings
• Convoluted forms are effective in enhancing
interactions with the surroundings. A long common
boundary provides a greater probability of movements
across
• A compact patch contains higher species richness than
an elongated patch that has fewer interior species
• Interior area adds species at a greater rate than
increasing edge area
Convoluted patches have a long perimeter and abundant exchanges with
the matrix. A convoluted patch causes complex patterns of turbulence in
water and wind flow. Most turbulence will be on the outside of a-remnant
patch, and the inside of a disturbance patch
The turbulence may create considerable microheterogeneity in
soil,water,vegetation, and fauna surrounding a remnant patch
BOUNDARIES AND ECOTONES
Sharp boundaries from human activities
Gradual ecotones in natural landscapes
Edge habitat and species
• Large patches contain interior conditions that foster
interior species absent in small patches
• Edge width varies according to wind direction, sun
direction, and internal edge structure
Edge width
Edge abruptness | Edge as filter
PATCH CONFIGURATION AND CONTEXT
The distance between patches and the characteristics of the context
influence species
Consider the contribution of patches to the landscape structure
• The orientation of the long axis of the patch is key to
several ecological processes
From Forman 1995
• Population Viability Analysis PVA is used to determine
the size of populations needed for long term survival. It
takes into account environmental, demographic and
genetic variables that determine extintion probabilities for
each species
• Minimum patch area is the smallest patch needed to
sustain specific species or ecosystem functions
Appendix B in the ELI document
ex. Bear 900ha, grizzly 2800, cougar 220.000
rodents, rabbits 1 to 10ha
Protection of habitat patches of 55ha appears to capture
75% of species requirement in the ELI survey.
This will not capture particularly area-sensitive species