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Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts

Journal of Arid Environments

By:
, , , and
DOI: 10.1016/j.jaridenv.2008.02.019

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Abstract

Biological soil crusts (BSCs) are an integral part of dryland ecosystems and often included in long-term ecological monitoring programs. Estimating moss and lichen cover is fairly easy and non-destructive, but documenting cyanobacterial level of development (LOD) is more difficult. It requires sample collection for laboratory analysis, which causes soil surface disturbance. Assessing soil surface stability also requires surface disturbance. Here we present a visual technique to assess cyanobacterial LOD and soil surface stability. We define six development levels of cyanobacterially dominated soils based on soil surface darkness. We sampled chlorophyll a concentrations (the most common way of assessing cyanobacterial biomass), exopolysaccharide concentrations, and soil surface aggregate stability from representative areas of each LOD class. We found that, in the laboratory and field, LOD classes were effective at predicting chlorophyll a soil concentrations (R2=68-81%), exopolysaccharide concentrations (R2=71%), and soil aggregate stability (R2=77%). We took representative photos of these classes to construct a field guide. We then tested the ability of field crews to distinguish these classes and found this technique was highly repeatable among observers. We also discuss how to adjust this index for the different types of BSCs found in various dryland regions.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Visually assessing the level of development and soil surface stability of cyanobacterially dominated biological soil crusts
Series title:
Journal of Arid Environments
DOI:
10.1016/j.jaridenv.2008.02.019
Volume
72
Issue:
7
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Arid Environments
First page:
1257
Last page:
1264
Number of Pages:
8