Comment on: Grazing disturbance promotes exotic annual grasses by degrading soil biocrust communities

Authors: O'Connor, Rory; GERMINO, MATTHEW - U.S. GEOLOGICAL SURVEY (USGS)

Submitted to: Ecological Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2020
Publication Date: 12/15/2020
Citation: O'Connor, R.C., Germino, M.J. 2020. Comment on: Grazing disturbance promotes exotic annual grasses by degrading soil biocrust communities. Ecological Applications. 31(7). Article e02277. https://doi.org/10.1002/eap.2277.
DOI: https://doi.org/10.1002/eap.2277

Interpretive Summary: Biological soil crusts are a part of rangelands in the western United States of America and are highly sensitive to disturbances (e.g., livestock grazing, fire, erosion, animal movement). In this article we explain that evaluations of the relationships between biological soil crusts, invasive annual grasses and livestock grazing also need to account for land-use history, for example the number of times the site was burned from wildfires. Additionally, it is important to recognize that livestock grazing cannot be considered merely grazed or not grazed. Grazing is determined by the number of animals, their duration on the site and the types of forage available. We provide examples from the literature describing how wildfire disturbance damages biological soil crusts and the time that it takes to restore the biological soil crust, which spans several decades to centuries. The literature also shows how entangled fire, grazing and invasive annual grass abundance is in western rangelands. By ignoring the complex interactions of grazing and fire disturbance on the plant communities and biological soil crusts our ability to effectively manage rangelands is limited. This article is of interest to natural resource managers and scientists.

Technical Abstract: Biological soil crusts are a part of rangelands in the western United States of America and are highly sensitive to disturbances (e.g., livestock grazing, fire, erosion, animal movement). In this article we explain that evaluations of the relationships between biological soil crusts, invasive annual grasses and livestock grazing also need to account for land-use history, for example the number of times the site was burned from wildfires. Additionally, it is important to recognize that livestock grazing cannot be considered merely grazed or not grazed. Grazing is determined by the number of animals, their duration on the site and the types of forage available. We provide examples from the literature describing how wildfire disturbance damages biological soil crusts and the time that it takes to restore the biological soil crust, which spans several decades to centuries. The literature also shows how entangled fire, grazing and invasive annual grass abundance is in western rangelands. By ignoring the complex interactions of grazing and fire disturbance on the plant communities and biological soil crusts our ability to effectively manage rangelands is limited. This article is of interest to natural resource managers and scientists.