ENWC201 Lecture Notes - Lecture 12: Phragmites, Habitat Fragmentation, Insular Biogeography
Lecture 12: Habitat Loss
• Habitat: the physical and biological resources required by an organism for its survival
and reproduction
• Conversion of agriculture and urbanization are big threats
• Habitat loss, degradation and fragmentation
o The largest threat to biodiversity and the leading case of animals extinctions in
the world
• Habitat degradation
o Can have many causes
▪ prime examples
• livestock grazing
o rangelands about 25% of terrestrial land
• invasive species
o phragmites
• Habitat fragmentation: reduction in the area covered by habitat, change in
configuration
o The division of large habitat area into smaller patches
o Reflected in landscape
▪ Small patches and big patches
o Smaller patches will have less population stability and less biodiversity
o Island biogeography theory
▪
o edge effects (patch of forest ex)
▪ air and soil temperature, moisture and light
• sunlight does not go far in to support the brush
▪ vegetation density
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