Slope aspect effects microclimate in desert environments


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Slope aspect effects microclimate in desert environments (Monger and Bestelmeyer 2006)

  • Slope aspect effects microclimate in desert environments (Monger and Bestelmeyer 2006)

  • Vegetation composition changes as hill slope position changes (Bridge and Johnson 2000)



Do soil characteristics change as hill slope position changes?

  • Do soil characteristics change as hill slope position changes?

  • Does soil creep behave as predicted in a semi-arid climate? And what effect does vegetation community have on soil creep?

  • How does vegetation community and soil formation interact at different hill slope positions?





34 22’ 6.78"N 106 32’ 11.83"W

  • 34 22’ 6.78"N 106 32’ 11.83"W

  • Slope sequences followed transects previously setup by Esteban Muldavin

  • Bedrock

    • schist
    • gneiss
    • vein Quartz
    • quartzite


Hill Slope

  • Hill Slope

  • Soil Characteristics

  • Vegetation Community



Slope Sequences

  • Slope Sequences

    • 5 different north and south facing slopes
    • 4 soil pits dug on each slope
    • Total of 40 pits
    • Aspect of each slope was measured




Line Transects

  • Line Transects

    • 40 transects completed
    • 11 m transects
    • Parallel to slope position
    • Basal area and Canopy measured


Graphed as a function of hill slope position:

  • Graphed as a function of hill slope position:

    • Soil depth
    • Soil Texture
    • Soil Color
  • Compared soil depth and slope aspect to:















Two different soil types

  • Two different soil types

    • Both North- and South-facing slopes
    • Slope Sequences 2 and 4
    • Slope Sequences 3 and 6 (and possibly 1)
  • Fine soil material from wind (eolian) source



Primarily A horizons



Both North- and South-facing slopes

  • Both North- and South-facing slopes

  • Soil very deep (>25 cm)

    • Well developed soil column
    • Thin A horizon
    • Thick B horizon
    • Strong CaCO3 film and filament development
  • Soil likely much older than soil on Slope sequences 2 and 4



“Soil horizon development as determined by landform age…” (McAuliffe 1994).

  • “Soil horizon development as determined by landform age…” (McAuliffe 1994).

  • Different soil horizons and types

    • Landform same age over Los Piños
    • How are there such distinctly different soil types?
      • Change in climate
      • Change in depositional regime
      • Effect of grazing










The vegetation community may have an effect on the soil of both north and south facing slopes.

  • The vegetation community may have an effect on the soil of both north and south facing slopes.

  • % Grass Basal Area vs. Soil Depth

  • % Canopy of trees vs. Soil Depth

  • % Grass Basal Area vs. Aspect

    • Grass prefer to live on shallower slopes




Soil characteristics changed with respect to hill slope position

  • Soil characteristics changed with respect to hill slope position

  • Soil depth and aspect are likely linked to vegetation community

  • Vegetation may have an effect on soil transport

  • North and South facing slopes appear to behave differently, likely due to the differences in vegetation community, slope aspect, and microclimate.



Les McFadden, Esteban Muldavin

  • Les McFadden, Esteban Muldavin

  • Jennifer Johnson

  • Amaris Swann

  • Summer REUs: Shayla Burnett, Harmony Lu, Rick Duran, Mitch Nakai, Cynthia Malone, Natasha Ribiero, Melissa Shaginoff, Antonio Nevarez, Amanda Labrado, Elida Iniguez

  • Summer Interns: Brenda Nieto

  • National Science Foundation



McAuliffe RJ. (1994). Landscape Evolution, Soil Formation, and Ecological Patterns and Processes in Sonoran Desert Bajadas. Ecological Monographs, Vol. 64, No. 2: 111-148.

  • McAuliffe RJ. (1994). Landscape Evolution, Soil Formation, and Ecological Patterns and Processes in Sonoran Desert Bajadas. Ecological Monographs, Vol. 64, No. 2: 111-148.

  • Monger HC and Bestelmeyer BT. (2006). The soil-geomorphic template and biotic change in arid and semi-arid ecosystems. Journal of Arid Environments. 65: 207-218.

  • Daniels RB and Hammer RD. Soil Geomorphology. Wiley (1992): New York.

  • Bridge SRJ and Johnson EA. (2000). Principles of Terrain Organization and Vegetation Gradients. Journal of Vegetation Science, Vol. 11, No. 1: pp. 57-70

  • Francis CF. Plants on Desert Hillslopes. Edited by: Athol D. Abrahams and Anthony J. Parsons. Geomorphology of Desert Environments. Chapman and Hall (1994): London.






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