riparian woody plant diversity and forest structure along an urban-rural gradient

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riparian woody plant diversity and forest
structure along an urban-rural gradient

• Wanghui
• 2005.11.4

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background knowledge

• A component of a multidisciplinary research
• serve important role in maintaining water
  quality and biodiversity
• objective forest structure and woody vegtation
  diversity indices of riparian communities in
  response to an urbanization gradient in west
  Georgia ,USA

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• urban uses
• 1992 8.1 million hectares
• 2020 22.3 million hectares
• 2040 32.8 million hectares (wear,2002)
• human influences history
• 17-19th century agriculture exploitural
  exploitation
• 20th century timber exploitation
• 1964 forest recovery and renewal
• trends(1945-1992) urban area increase ,
  agricultural uses declinde , forestland not
  decline

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• Urbanization ,imperious surface indirectly
  influnce modify hydrologic , nutrient ,
  disturbance cycles , introducing invasive species
  ,change of microclimate condition
• studies plant , animal , insect , assemblages ,
  soil , water quality along urban gradient ,
  further, etc.

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Method

• Study area Muscogee and Harris ( table 1)
• Fundamental units watershed
• Aerial photographs (1-m) ( table 2 )
• Sampling procedures six riparian community ,
  six transects ( 35-m) in each one , 100-m apart
  from the stream , 10- m long for each plots ,
  15-m apart , two on each side of the stream

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Sampling procedures

• Forest stand woody plants gt 2.5cmDBH (1.6m
  height )
• Regeneration layer (1m1m , 5, random ) woody
  stems lt 2.5cmDBH
• Forest cover LAI(1m from the ground ,20 along
  each transects ) ,averaged by transect and by
  site .

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Statistical analysis

• Woody vegetation diversity indices importance
  values , total number of species , shannon
  diversity index , evenness index (forest stand
  ,regeneration layer )
• Native and non-native
• table 3

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Results and discussion

• Forest stand 61(5 non - native )
• Regeneration layer 52(5 non - native )
• Common 38
• Lsl (non-native) dominant in closest to the urban
  center .
• Proportion of on-natives , Hr , basal area
  demonstrate significant relationship with
  urbanization parameter
• table4

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Urbanization
Percent forest cover decrease
Change in water table and soil moisture
Forest productivity decreace
Productivity ,stability, resistance
Competitive advantage for Invasive species
Ecosystem stability and Complexity decrease
Diversity presence of Non-native species
increase
Uncertain potential effect On eco functinon and
structure
Riparian communities Diversity decrease
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Next work

• How change in water flow
• Hydrologic drought
• Hydrology and riparian plant composition
• Integrate with other facets of the overall west
  Georgia project

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Q A!