Remote Sensing of

Biological Soil Crusts

Jonathan A. KeyM.S. Environmental Science

University of Colorado Denver

Moab, Utah

Small patches of vascular plant growth

Morphology and Structure

Cyanobacterial microfilamentsBiological soil crust macrostructure

Arches NPS Arches NPS

Also known as cryptogamic, microbiotic, and microphytic soils.

Consist of photosynthetic cyanobacteria, lichens, green algae, fungi,

nonvascular plants, and various bacteria.

Geographic Extent

• Occupy a wide range of

climates

• Species composition of

alpine tundra is similar

to that of cool desert

• Constitute up to 75

percent of the living

ground cover

www.ArcheaologySouthWest.org

Selection of Data Sets

Landsat 5 Thematic Mapper

• Multispectral imagery using 7

bands

• Large enough temporal range

to do an analysis spanning

more than ten years

• Decent spatial resolution

• Data acquired was from May

18, 1996 and May 6, 2009

Study SceneColorado Plateau

May 18, 1996

Workflow Process

Image Acquisition User Analysis

• NDVI, Tasseled

Cap, BSCI

• Contrast Adjust

Preprocessing

• Band layer

stacking

• Mosaicking

Unsupervised

Classification

Supervised

Classification

• Training sites

• Max likelihood

• Determination of

# of classes

Error Analysis

• 2nd set of

training sites

• Confusion

matrix

Report Class

Statistics

Class Change

Analysis

Repeat for Later

Image

• USGS

EarthExplorer

• ISODATA

NDVI

Spectral Transformation

BSCI

May 18, 1996

Biological Soil Crust Index

• Analysis of this technique with ground truth data suggests

that BSCs can be detected as long as they cover

approximately one third of the pixel (10 m for Landsat)

(Chen et al. 2005)

Supervised ClassificationDesert Vegetation

Biological Soil Crust

Panchromatic background image

May 18, 1996

Class Change Analysis

• Pixel-based class change analysis indicates that there

was a 124 percent increase in microbiotic soil coverage

from May 1996 to 2009

Class Change Analysis (Percentage)

ClassAlpine

Veg

Biological Soil

CrustSnowcap

Bedrock/Dry

SoilClouds Desert Veg Water Rural Dev Crops

Biological Soil

Crust0.079 72.318 3.981 24.878 0.607 21.889 3.2 0.492 0.362

Desert Veg 8.562 1.248 2.136 3.684 1.097 40.586 0.146 37.235 4.206

Alpine Veg 45.824 0.075 15.212 0.049 2.75 1.305 2.993 1.712 6.347

Water 0.031 0 0.588 0.001 0 0.001 70.224 0 0

Clouds 2.038 1.295 42.073 1.917 73.967 0.893 10.2 2.558 1.285

Snowcap 4.359 0 13.788 0.05 0.468 0.023 0.093 0.01 1.332

Bedrock/Dry Soil 11.967 21.803 16.786 66.11 17.694 18.23 10.259 9.769 3.098

Rural Dev 25.711 2.776 5.104 3.122 3.254 14.351 2.751 41.048 14.082

Class Changes 54.176 27.682 86.212 33.89 26.033 59.414 29.776 58.952 30.712

Image Difference -45.058 124.896 -24.829 20.702 -20.19 -40.162 -27.59 205.334 704.3

Error Matrix (Percent)

Class Alpine VegBiological

Soil CrustSnowcap Clouds Desert Veg Water Crops

Bedrock/Dry

Soil

Rural

DevelopmentTotal

Alpine Veg 96.58 0 7.35 0.01 5.45 0.11 13.06 0.03 18.28 21.3

Biological Soil

Crust0.04 88.88 0 0 0.11 0 0 5.78 0.94 14.67

Snowcap 0.36 0 89.32 12.37 0.02 0.43 0 0 0 3.84

Clouds 0.19 0.01 3.27 87.62 0.23 0.03 0 0.41 0.57 6.61

Desert Veg 1.23 4.24 0.04 0 93.69 0 0.71 0.32 5.71 17.23

Water 0 0 0 0 0 99.36 0 0 0 3.67

Crops 0.34 0 0 0 0.03 0 65.17 0 3.66 0.37

Bedrock/Dry Soil 0 6.83 0.02 0 0.47 0.07 0 93.46 2.97 28.91

Rural

Development1.26 0.04 0 0 0.01 0 21.06 0 67.86 3.39

Error Report and Uncertainties

Potential sources of error

• BSCI was developed while studying Gobi Desert with ETM+

• Landsat 5 has relatively low radiometric resolution

• Overlap of desert vegetation and microbiotic soils and season

variation

• Training site selection not based on ground truth data

Climatic Influence

• Soil stability reduces wind-blown dust

• Dust deposited on snowcapped mountains will decrease

the albedo of the surface

Painter et al. 2007

www.panoramio.com

Closing Statements

• Ground truth data is required for this study to mean

anything

• Based on this analysis there has been a substantial

increase in biological soil crust coverage from 1996 to

2006 in the Colorado Plateau region.

• This technique provides a cost-effective method for

continued monitoring of microbiotic soils

Any thoughts or questions?

ReferencesBelnap, J., & Gardner, J. S. (1993). Soil microstructure in soils of the Colorado Plateau: the role of the cyanobacterium Microcoleus vaginatus.

Great Basin Naturalist, 53(1), 40-47.

Belnap, J., & Eldridge, D. (2003). Disturbance and recovery of biological soil crusts. In Biological soil crusts: structure, function, and

management (pp. 363-383). Springer Berlin Heidelberg.

Chen, J., Yuan Zhang, M., Wang, L., Shimazaki, H., & Tamura, M. (2005). A new index for mapping lichen-dominated biological soil crusts in

desert areas. Remote Sensing of Environment, 96(2), 165-175.

Harper, K. T., & Belnap, J. (2001). The influence of biological soil crusts on mineral uptake by associated vascular plants. Journal of Arid

Environments, 47(3), 347-357.

Karnieli, A., Kidron, G. J., Glaesser, C., & Ben-Dor, E. (1999). Spectral characteristics of cyanobacteria soil crust in semiarid environments.

Remote Sensing of Environment, 69(1), 67-75.

Painter, T. H., Barrett, A. P., Landry, C. C., Neff, J. C., Cassidy, M. P., Lawrence, C. R., & Farmer, G. L. (2007). Impact of disturbed desert soils

on duration of mountain snow cover. Geophysical Research Letters, 34(12).

Peterson, P. (Ed.). (2001). Biological soil crusts: ecology and management. US Department of the Interior, Bureau of Land Management,

National Science and Technology Center, Information and Communications Group.

Van der Meer, F. D., van der Werff, H., van Ruitenbeek, F. J., Hecker, C. A., Bakker, W. H., Noomen, M. F., ... & Woldai, T. (2012). Multi-and

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Weber, B., Olehowski, C., Knerr, T., Hill, J., Deutschewitz, K., Wessels, D. C. J., & Büdel, B. (2008). A new approach for mapping of biological

soil crusts in semidesert areas with hyperspectral imagery. Remote Sensing of Environment, 112(5), 2187-2201.