Landscape patterns and ecosystem processes

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Landscape patterns and ecosystem processes

• ESM 215
• March 3, 2003

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Pattern and process in ecology

• Agents of pattern formation
• environmental heterogeneity
• biological pattern process
• disturbance processes

Biophysical Patterns and Processes
Population community patterns and processes
Disturbance Pattern and Processes
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Topics

• Landscape pattern and regional climate processes
• Edge effects on microclimate and ecosystem
  processes
• Fragmentation patterns and ecosystem processes

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Downtown Sacramento in visible and thermal imagery
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Climates of vegetated surfaces

• 1. Surface Energy balance
• Q QH QE dQS dQP
• (H-sensible heat, E-latent heat, S-soil heat,
  P-photosynthesis)
• 2. Physical surface variables
• albedo (.1- .9)
• emissivity (0.7 - 0.99)
• aerodynamic roughness (0.00001-10m)
• soil thermal parameters
• thermal conductivity (0.1-5 W/m/K)
• heat capacity (800-4200 J/kg/K)
• thermal diffusivity (0.1-20 m2/s)
• soil moisture (f(texture))

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Climate of vegetated surfaces (2)

• 3. Biological surface variables
• BRDF
• canopy reflectance, transmittance,
  absorption
• leaf area index (0.1-9)
• canopy resistance (20-400 s/m)
• canopy height/roughness length
• production/respiration
• 4. Local energy and water balance regimes
• Bowen Ratio

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Patterns in land surface Bowen Ratio and
temperature
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South Florida average maximum temperature (C)
during the 2-month period for the (a) 1900, (b)
1973, and (c) 1993 landscapes. The average
maximum over land for the two-month period
increased by about 0.4C for the 1973 landscape,
and by 0.7C for the 1993 landscape, compared to
the model run when the 1900 landscape was used
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The change in JuneJuly total convective rainfall
for (a) 19731900, and (b) 19931900.
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Key points

• Strong atmosphere land surface interaction in
  regional and local climates
• Landscape factors such as land use and topography
  can affect regional temperature and precipitation
  means and variances
• Downwind effects of land use can persist for km
  to 10s of km

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Edge effects on microclimate and ecosystem
processes

• What is an edge?
• Physical
• Chemical
• Biological
• Behavioral
• Spatial and temporal scale-dependence
• Typically based on structural and physical
  features, human scale
• Vegetation type, landuse, dominant land features,
  and topography

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Boundary Abruptness and Magnitude
Abrupt, high magnitude
Abrupt, low magnitude
Gradual transition
Johnson et al. 1992
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Point Edge Effect Model

• Total edge effect of a point y within the patch
  is the sum of the point edge effects along the
  edge

Malcolm 1994
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Malcolm, JR Ecology 1994
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Chen et al Ecol. Appl. 1995
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Chen et al Ecol. Appl. 1995
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Chen et al Ecol. Appl. 1995
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Abiotic Observations
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Mesquita et al. 1999 Biological Conservation
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Didham. Oecologia 1998.
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Laurance et al. Conservation Biology 2002.
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Laurance et al. Conservation Biology 2002.
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Edge effects in tropical rainforests
Laurance et al. Conservation Biology 2002.
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Hyderdynamics in fragmented landscapes?
Laurance, W. Journal of Vegetation Science 2002.
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Fragmentation patterns and ecosystem processes

• Wind Regime
• Hydrology and water quality
• Nutrient Cycling

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http//asuwlink.uwyo.edu/hiemstra/Overview.html
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Jones et al. Landscape Ecology 2001
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• 86 var explained
• road crossings
• agricultural land
• urban
• riparian agriculture
• slope gradient variance

58 var explained riparian forest nitrate
deposition
65 var explained road density - riparian forest
Jones et al. Landscape Ecology 2001
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Hunsaker. Bioscience 1995