Natural Dist-Fire

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Habitat Fragmentation
By Kaushik Mysorekar
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Objective

• To enlighten the causes and consequences of
  habitat fragmentation followed by few
  recommendations to restore biodiversity and
  natural environment/habitat and prevent of
  fragmentation.

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What is habitat fragmentation?

• Breaking up of large continuous habitat into
  smaller and isolated parcels.
• Or transformation of original continuous forest
  landscape into smaller and isolated remnant
  patches of plantation or non-forest habitat.
• Or simply disruption of continuity.

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Natural Disturbance -Fire
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Forest clearcuts contribute to habitat loss
         Photo by Susan Hannon

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Stages of the fragmentation process
Development of small patches within a large area
of continuous forest
Expansion of the developed patches
Ultimately to conversion of the dominant land
cover type from forest to human land use
  (Source http//chesapeake.towson.edu/landscape/
forestfrag/process.asp)
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Consequences of Fragmentation
(Lindenmayer and Franklin 2002)
(Meffe and Carroll 1997)

• Major ecological consequences of habitat
  fragmentation are
• Habitat loss
• Subdivision of habitat
• Patch isolation
• Edge effects
• Others o
• Loss of native plants and animal species
• Invasion of exotic species
• Increased soil erosion
• Decreased water quality

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Species vulnerable to habitat fragmentation



(Meffe and Carroll 1997)

• Rare species
• Species with large home ranges
• Species with limited power of dispersal
• Species with low reproductive potential
• Species with short life cycle
• Species of habitat interior
• Species dependent on resources that are
  unpredictable in time or space
• Ground nesting birds
• Species exploited or persecuted by people.

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Which features of habitat fragmentation matter?

• Edge Effect
• Microclimatic changes
• More light
• More wind
• Low humidity
• Higher temperature

• Alters native plants and animals
• Reduce the survival of the species of the
  original habitat
• Advantageous for invasive species
• Consequentially excluding the native species.

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• Fragment size/area
• Influences the ecological processes occurring
  therein
• Large fragments have
• variety of soil types
• greater topographic
• microclimatic variation
• greater number of habitat types
• Smaller fragments - larger edge habitat and less
  interior
• larger fragments- less edge habitat and larger
  interior
• Species richness decreases with decrease in
  fragment area.

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Fragment shape
Shape can be calculated by perimeter/area
ratio Square - low P/A ratio- greater interior
than rectangle of the same area Surprisingly
US have high P/A ratio for the reserves for
nature protection Fragments with a highly
irregular ,convoluted boundary will have greater
exchange of nutrients,materials and organisms.
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Fragment Connectivity
Fragments are connected by corridors (fencerows,
streams, roads), which does ecological functions
such as Connectivity with riparian corridors is
important to prevent soil erosion and to maintain
high water quality Wide corridors reduce the
edge effects human disturbances Vegetative
corridors facilitate the movement the of animals
and plants and prevents species extinction.
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Fragment heterogeneity
Heterogeneous fragments support greater number
and variety of species Heterogeneous fragments
show greater variation of microclimate Plants
and animals are less susceptible to local
extinction.
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Recommendations
(Meffe and Carroll 1997)
(Collinge 1996)


(Lindenmayer and Franklin 2002)

• Conduct a landscape analysis, determine the
  pattern of habitats and connections
• Avoid any further fragmentation or isolation of
  natural areas and
• Edge effects can be minimized by establishing
  buffer zones

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Recommendations cont.

• Maintain native vegetation along streams,
  fencerows, roadsides, to minimize edge effects
  and human disturbances
• Protect traditional wildlife migration route and
  human activities should be steered away
• Minimize the area dominated by weedy or exotic
  species (roadsides)
• Activities against natural disturbances such as
  fire, windthrows are important for native flora
  and fauna.

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THANK YOU