Biological soil crusts effects on surficial processes in sandy soils of a pinyon-juniper woodland

Authors: PHELPS, ERIN - University Of Arizona; Williams, Christopher; Polyakov, Viktor; RUTHERFORD, WILLIAM - Bureau Of Land Management; Heilman, Philip; HU, JIA - Oregon State University; JOHNSON, JUSTIN - N3b Los Alamos; CHAVEZ, RAVEN - Bureau Of Land Management; MITCHELL, RACHEL - University Of Arizona; AL-HAMDAN, OSAMA - Texas A&M University, Kingsville; Pierson Jr, Frederick; SPAETH, KENNETH - Retired ARS Employee; WEI, HAIYAN - University Of Arizona

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/28/2026
Publication Date: 9/10/2026
Citation: Phelps, E.L., Williams, C.J., Polyakov, V.O., Rutherford, W.A., Heilman, P., Hu, J., Johnson, J.C., Chavez, R., Mitchell, R., Al-Hamdan, O.Z., Pierson Jr, F.B., Spaeth, K., Wei, H. 2026. Biological soil crusts effects on surficial processes in sandy soils of a pinyon-juniper woodland. Rangeland Ecology and Management. 109:115-127. https://doi.org/10.1016/j.rama.2026.07.008.
DOI: https://doi.org/10.1016/j.rama.2026.07.008

Interpretive Summary: Biological soil crusts (biocrusts) are a broadly occurring living and ecologically important ground cover on rangelands and woodlands around the world. The role biocrusts play in regulating ecosystem processes is complex and determining their influence on surface hydrology and soil erosion remains a key challenge for scientists and land managers. This study aimed to inform land managers in the Colorado Plateau, USA, and similar domains regarding the influence of intact biocrusts on ground surface conditions and surface hydrology and erosion processes and thus provide a basis for forecasting potential short-term hydrologic and erosion impacts of their disturbance. Rainfall simulation experiments were conducted in well-established and developing biocrust areas at a single pinyon (Pinus spp.) and juniper (Juniperus spp.) woodland site in Utah, USA. Areas with well-established, undisturbed biocrusts dominated by dark cyanobacteria exhibited greater soil aggregate stability and ground surface roughness and less hydrologic vulnerability and soil erosion potential than areas in earlier stages of development (similar to post-disturbance conditions) and dominated by light cyanobacteria. However, the study results in context with observed residual natural erosion features at the site suggest that surface protection against water driven erosion afforded by well-developed biocrusts may be limited to low intensity or short duration events under dry soil conditions. The study area is subject to frequent high intensity rainfall events on moist soils during the summer monsoon season. The study results provide quantitative data on the effects of biocrusts on surface conditions and hydrology and erosion processes. Further, the results suggest management actions (such as woody plant removal) that temporarily disturb biocrusts should consider the potential short-term hydrologic and erosion impacts in context with projected longer-term benefits of re-establishing the necessary vegetation and/or ground cover structure and attributes needed to limit hydrologic and soil loss vulnerabilities. Such management actions targeting long-term vegetation enhancements and/or improved hydrologic function should expect short-term increases in runoff and erosion where well-established biocrusts are disturbed.

Technical Abstract: Biological soil crusts (biocrusts) are a broadly occurring and ecologically important ground cover on water-limited lands around the world. The variable cover and developmental stages of biocrusts can modify soil properties and ground surface conditions and thereby influence hillslope infiltration, runoff, and erosion rates. However, biocrust effects on runoff and erosion are complex and highly variable. Although many studies have investigated these relationships, findings remain conflicting, particularly for coarse-textured soils. We applied a suite of soil, ground surface, hydrology, and erosion experiments at the point and plot (0.5 m2) scales on coarse-textured soils to quantify effects of Early versus Late biocrust succession on ground surface conditions and infiltration, runoff, and erosion processes. Soil aggregate stability and ground surface roughness were greatest in later successional stages of biocrust development and, across all plots, were positively correlated with the percentage cover of dark cyanobacteria (R2=0.49-0.60). Runoff and erosion rates from rainfall simulation experiments (100 mm · h-1, 45 min) on dry antecedent moisture conditions were 2- and 6-fold greater for Early succession plots (25 mm · h-1 and 153 g · m-2) than Late succession plots (11 mm · h-1 and 24 g · m-2). Runoff responses across Early and Late succession plots were primarily controlled by and negatively related to the percentage cover of dark cyanobacteria, soil aggregate stability, and ground surface roughness. Sediment yield was regulated by the amount of runoff and negatively related to cover of dark cyanobacteria, soil aggregate stability, and ground surface roughness due to respective influences on runoff generation. Our study results offer land managers, producers, researchers, and model developers valuable insights into the ecohydrologic role of biocrusts on drylands and provide context for forecasting ecosystem responses to biocrust perturbations from natural disturbances and management actions.