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Quick Review: Scale Theories

Quick Review: Scale Theories. Characteristic Scales: Example. Hierarchy theory: example. Objective: predict forest stand dynamics over 100 years. Constraints/ boundaries. physiography soil parent materal landscape position. Landscape. Mechanisms. Temporal scale. Stand Dynamics:

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Quick Review: Scale Theories

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  1. Quick Review: Scale Theories

  2. Characteristic Scales: Example

  3. Hierarchy theory: example Objective: predict forest stand dynamics over 100 years Constraints/ boundaries physiography soil parent materal landscape position Landscape Mechanisms Temporal scale Stand Dynamics: Tree diameters Spp Composition Stand Stand Stand Spatial scale Gap Gap Gap Gap Gap tree physiology root respiration annual productivity Gap Gap Gap Gap Gap

  4. Hierarchy Theory: Example CLIMATE and GEOLOGY Disturbances Living and Dead Biomass succession productivity decomposition soil nutrients competi-tion

  5. Hierarchy Theory: Assignment • For Tuesday, February 1 • Create your own diagram of a system based on hiearchy theory. • Email your diagrams to me by monday, January 31 @ NOON. Send as either a PowerPoint file or as a *.jpg file. • I will randomly choose diagrams to discuss. Be prepared to describe your system and your diagram. If you are not randomly chosen, you will be next time! • Be creative! Feel free to diagram political, social, aquatic, terrestrial, systems. Don’t copy my examples.

  6. Abiotic constraints to landscape pattern and processes Lecture 4January 27, 2005

  7. scale landscape pattern non-spatial processes landscape processes Pattern and Process

  8. If a process is NOT a function of pattern, then it is a non-spatial process. If a process is a function of pattern, then it is a spatial, or landscape process. = ≠ Pattern and Process

  9. Landscape Processes Landscape Processes are sensitive to landscape pattern because they include the lateral transfer of information, energy, or matter. Information Matter Energy

  10. Landscape Processes If there are no landscape/spatial processes, landscape configuration DOES NOT MATTER. Other examples of Landscape Processes?

  11. Pattern and Process Abiotic Constraints Level of Focus for this class landscape pattern landscape processes non-spatial processes What are the components (explanation)? - Biology - Human activity - Disturbance

  12. Characteristic Scales of Abiotic Constraints Pedogenisis Climate Landform From Urban et al. 1987

  13. Abiotic Constraints on Landscape Pattern and Function • Climate = long term or prevailing • weather affecting the distribution • of energy and water in a region • Temperature • Moisture Landform = geomorphic features affecting physical relief and soil development

  14. Abiotic Constraints: Climate Climate Definitions Climate Regime: composite, long-term weather patterns of a region. Weather: Finer temporal scale changes in temperature, precip, e.g., daily fluctuations Microclimate: Finer spatial scale differences in temperature and precip, e.g., N and S sides of hill

  15. Climate controls several large scale processes:Hydrologic cycleLandforms and erosion cyclesPlant/animal life cycles and distributionsFire and wind disturbance regimes From Bailey 1998

  16. Climate and the Hydrologic Cycle Actual Evapotranspiration (AET) is the quantity of water that is actually removed from a surface due to evaporation and transpiration. Potential Evapotranspiration (AET)is the maximum water removal possible (w/o control). PET >> AET.

  17. Climate and the Biota Curtis 1959: Climate and the Wisconsin tension zone

  18. Climate and the Biota Long-term climate change and species distributions • Distributions of biota have • changed due to Milankovich cycles • – which appear to be related to • glacial/interglacial periods. • In response, biota may evolve and speciate, migrate, or go extinct. • Ecotones have shifted drastically in response to long-term climate change, but species respond individualistically, • not as communities.

  19. Climate and Disturbance Direct (Weather): Wind Speed Wind Duration Lightening Strikes Overland flow Flood magnitude Flood duration Indirect: Fuel Quantity Fuel Moisture

  20. Abiotic Constraints: Landform • Next level down in hierarchy of constraints. • Modifies and is modified by climate. • Provide the template for disturbance and biotic responses. Landform

  21. Landforms and Geomorphology • Landforms affect water movement and concentration, and soil development differences. • Topography and gravitational movement of water, and evapotranspiration create a toposequence or catena of soils. Erosion rates vary with rock type and climate: enough moisture for soil development and vegetative cover?

  22. Abiotic Constraints: Landform and Climate Interactions Landform and climate interact at all scales (continental to landscape to site). Elevation, aspect, and surface texture interrupt air masses and influence energy input from sunlight, and precipitation and nutrient inputs.

  23. Landform and Climate Interactions Example: Greater insolation on south slopes causes warmer sites, greater evapotranspiration. From Bailey 1998

  24. Landform, Climate, and Biota Example • Robert Whittaker (1952, 1953) sampled vegetation across a range of montane habitats, spanning elevation and aspect differences. • Found that species responded individualistically to changing environment. • But communities could be discerned within environmental space defined by elevational and aspect gradients.

  25. From Whittaker 1956

  26. Abiotic Constraints: Landscape Position An extension of landform and climate interactions Below large scale geomorphology or landform levels. Landscape position has been shown to be important in causing pattern in many different systems, including systems with relatively little relief. climate and landform landscape position

  27. Northern Lakes, Wisconsin (Kratz et al. 1991) Specific Conductance Low (Landscape Position) High Landscape Position and Hydrology Example: Position of lakes in the northern Wisconsin

  28. Landscape Position and Disturbance • Examples: • Hill slopes may shelter or expose forests to windthrow. • The greater vulnerability of ridges to fire ignition. • Wetlands and lakes in the Boundary Waters Canoe Area that serve as barriers to fire spread. Landforms interact with climate and increase or decrease susceptibility to disturbance.

  29. Landforms Glacial Climate Temporal scale Decadal Climate Weather Microclimate Short Fine Coarse Long Spatial scale Abiotic Confounding Factors Direct inferences between the abiotic template and landscape patterns are not always obvious! • Environmental gradients are correlated and do not always change in concert. For example, temperature and precipitation may be inversely correlated in mountains. • Physical factors all vary across scales and have their own unique variability across scales.

  30. Abiotic Confounding Factors Direct inferences between the abiotic template and landscape patterns are not always obvious! • Biotic responses to physical factors are not always predictable due to differential rates of establishment, growth, mortality. • Interactions such as competition may confound the relationships. • Disturbance may alter biotic composition.

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