Biotic soil crusts in relation to topography, cheatgrass, and fire in the Columbia Basin, Washington

Bryologist
By: , and 

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Abstract

We studied lichen and bryophyte soil crust communities in a large public grazing allotment within a sagebrush steppe ecosystem in which the biotic soil crusts are largely intact. The allotment had been rested from grazing for 12 years, but experienced an extensive series of wildfires. In the 350, 4 x 0.5 m plots, stratified by topographic position, we found 60 species or species groups that can be distinguished in the field with a hand lens, averaging 11.5 species groups per plot. Lichen and bryophyte soil crust communities differed among topographic positions. Draws were the most disturbed, apparently from water erosion in a narrow channel and mass wasting from the steepened sides. Presumably because of this disturbance, draws had the lowest average species richness of all the topographic strata we examined. Biotic crust species richness and cover were inversely related to cover of the invasive annual, cheatgrass (Bromus tectorum), and positively related to cover of native bunchgrasses. Integrity of the biotic crust was more strongly related to cheatgrass than to fire. In general, we observed good recovery of crusts following fire, but only in those areas dominated by perennial bunchgrasses. We interpret the resilience of the biotic crust, in this case, to the low abundance of cheatgrass, low amounts of soil disturbance and high moss cover. These fires have not resulted in an explosion of the cheatgrass population, perhaps because of the historically low levels of livestock grazing.

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Publication type Article
Publication Subtype Journal Article
Title Biotic soil crusts in relation to topography, cheatgrass, and fire in the Columbia Basin, Washington
Series title Bryologist
DOI 10.1639/0007-2745(2007)110[706:BSCIRT]2.0.CO;2
Volume 110
Issue 4
Year Published 2007
Language English
Publisher BioOne
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 18 p.
First page 706
Last page 722
Country United States
State Washington
Other Geospatial Columbia Basin
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