landscape mosaic. patch types desert vegetation

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