Lea A Condon, PhD
Dr. Lea Condon is studying how we can maintain and restore native plant communities with an emphasis on biological soil crusts in the presence of land management and disturbance with the U.S. Geological Survey’s Western Ecological Research Center.
Lea sees disturbances such as fire, floods, and human manipulations of the environment as opportunities to test our understanding of ecosystem function and plant community dynamics. She works closely with land managers, providing science to support their management questions and needs. Having a diverse background of employment, from private consultant for industry to federal research ecologist, she is well-equipped to execute advanced tools for ecosystem restoration, as well as identify and create new analytical and survey tools moving forward.
Lea has recent research filling the knowledge gap related to biological soil crusts (biocrusts) in the Great Basin ecoregion. This region has been prone towards increasing fire and invasion by non-native annual grasses that provide the fuel for those fires. The negative association between the abundance of biocrusts and non-native annual invasive grasses is one of the most consistent tools that we have in understanding how to minimize these grasses, which are threatening the existence of sagebrush ecosystems. This work encompasses related topics such as the successful restoration of biocrusts, the identification of land management practices that allow for the maintenance of biocrusts, the response of various morphogroups of biocrusts to disturbances as well identifying the associations between morphogroups and plant communities.
Professional Experience
Biologist, U.S. Geological Survey, 2020-present
Research Ecologist (post-doctoral fellow), U.S. Geological Survey, 2016-2020
Graduate Research Assistantship, Oregon State University, 2012-2016
Sabbatical Replacement, Topics in Wildland Fire, 2015
Teaching Assistant, Oregon State University, 2011-2012
Senior Plant Ecologist, Otis Bay Ecological Consultants, 2007-2011
Graduate Research Assistant, University of Nevada Reno 2005-2007
Contracted Botanist, Bureau of Land Management, 2003-2005
Biological Science Technician, U.S. Geological Survey, 2001-2003
Education and Certifications
Ph.D., Botany, Oregon State University 2016
M.S., Natural Resources and Environmental Science, University of Nevada Reno 2007
A.B. and B.A. in Plant Biology and Nature and Culture, University of California Davis 2001
Affiliations and Memberships*
American Bryological and Lichenological Society
Nevada Native Plant Society
Society for Ecological Restoration
Society for Range Management
Honors and Awards
Star Award, Department of the Interior, 2020
Science and Products
Season of grazing interacts with soil texture, selecting for associations of biocrust morphogroups
Livestock grazing, a widespread land use in semi-arid systems, is often placed in opposition to the perpetuation of biological soil crusts (“biocrusts”: lichens, mosses, and algal crusts including cyanobacteria) that live on the soil surface and provide ecosystem functions. The composition of biocrusts and vascular plants varies with climate, soils, and disturbance. In general, ruderal mosses and
Authors
Lea A. Condon, Roger Rosentreter, Kari E. Veblen, Peter S. Coates
Biological soil crusts are more prevalent in warmer and drier environments within the Great Basin ecoregion: Implications for managing annual grass invasion
Biological soil crusts (biocrusts) can thrive under environmental conditions that are stressful for vascular plants such as high temperatures and/or extremely low moisture availability. In these settings, and in the absence of disturbance, cover of biocrusts commonly exceeds cover of vascular plants. Arid landscapes are also typically slow to recover from disturbance and prone to altered vegetatio
Authors
Lea A. Condon, John B. Bradford, Peter S. Coates
Biocrusts indicators of livestock grazing effects on soil stability in sagebrush steppe: A case study from a long-term experiment in the northern Great Basin
Biocrusts are sensitive to changes in livestock grazing intensity in arid rangelands and may be useful indicators of ecosystem functions, particularly soil properties like soil stability, which may suggest the potential for soil erosion. We compared biocrust community composition and surface soil stability in a big sagebrush (Artemisia tridentata) steppe rangeland in the northwestern Great Basin i
Authors
Stella M. Copeland, Lea A. Condon, Roger Rosentreter, Jesse E.D. Miller, Maya Kahn-Abrams
Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?
No abstract available.
Authors
Lea A. Condon, Douglas J. Shinneman, Roger Rosentreter, Peter S. Coates
Biological soil crusts in ecological restoration: Emerging research and perspectives
Drylands encompass over 40% of terrestrial ecosystems and face significant anthropogenic degradation causing a loss of ecosystem integrity, services, and deterioration of social‐ecological systems. To combat this degradation, some dryland restoration efforts have focused on the use of biological soil crusts (biocrusts): complex communities of cyanobacteria, algae, lichens, bryophytes, and other or
Authors
Anita Antoninka, Akasha M. Faist, Emilio Rodriguez-Caballero, Kristina E Young, V Bala Chaudhary, Lea A. Condon, David A. Pyke
Components and predictors of biological soil crusts vary at the regional vs. plant community scales
Although biological soil crusts (biocrusts) occur globally in arid and semi-arid environments, most of our knowledge of biocrust cover and ecology is from a relatively small number of locations worldwide. Some plant communities are known to have high cover of biocrusts, but the abundance of biocrusts is largely undocumented in most plant communities. Using a data driven approach, we identified 16
Authors
Lea A. Condon, David A. Pyke
Not all fuel‐reduction treatments degrade biocrusts: Herbicides cause mostly neutral to positive effects on cover of biocrusts
In response to increasing fire, fuel‐reduction treatments are being used to minimize large fire risk. Although biocrusts are associated with reduced cover of fire‐promoting, invasive grasses, the impact of fuel‐reduction treatments on biocrusts is poorly understood. We use data from a long‐term experiment, the Sagebrush Steppe Treatment Evaluation Project, testing the following fuel‐reduction trea
Authors
Lea A. Condon, Margaret L Gray
Passive restoration of vegetation and biological soil crusts following 80 years of exclusion from grazing across the Great Basin
Restoration targets for biological soil crusts are largely unknown. We surveyed seven 80‐year‐old grazing exclosures across northern Nevada for biocrusts to quantify reference conditions at relatively undisturbed sites. Exclosures were associated with the following plant communities: Wyoming big sagebrush, black sagebrush, and areas co‐dominated by winterfat and Wyoming big sagebrush. Cover of bio
Authors
Lea A. Condon, Nicole Pietrasiak, Roger Rosentreter, David A. Pyke
Hydroseeding tackifiers and dryland moss restoration potential
Tackifiers are long‐chain carbon compounds used for soil stabilization and hydroseeding and could provide a vehicle for biological soil crust restoration. We examined the sensitivity of two dryland mosses, Bryum argenteum and Syntrichia ruralis, to three common tackifiers ‐ guar, psyllium, and polyacrylamide (PAM) ‐ at 0.5x, 1.0x, and 2.0x of recommended (x) concentrations for erosion control and
Authors
W. Dillon Blankenship, Lea A. Condon, David A. Pyke
Resiliency of biological soil crusts and vascular plants varies among morphogroups with disturbance intensity
Background and aimsDisturbance affects the ability of organisms to persist on a site, and disturbance history acts as a filter of community composition. This is true for vascular plants and morphological groups of biocrusts, which respond differently to disturbance. Although functioning arid ecosystems include both groups, filtering of morphological groups of biocrusts has not previously been comp
Authors
Lea A. Condon, David A. Pyke
Fire and grazing influence site resistance to Bromus tectorum through their effects on shrub, bunchgrass and biocrust communities in the Great Basin (USA)
Shrubs, bunchgrasses and biological soil crusts (biocrusts) are believed to contribute to site resistance to plant invasions in the presence of cattle grazing. Although fire is a concomitant disturbance with grazing, little is known regarding their combined impacts on invasion resistance. We are the first to date to test the idea that biotic communities mediate the effects of disturbance on site r
Authors
Lea A. Condon, David A. Pyke
Filling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success
Biological soil crusts contribute to ecosystem functions and occupy space that could be available to invasive annual grasses. Given disturbances in the semiarid shrub steppe communities, we embarked on a set of studies to investigate restoration potential of mosses in sagebrush steppe ecosystems. We examined establishment and growth of two moss species common to the Great Basin, USA: Bryum argente
Authors
Lea Condon, David A. Pyke
Non-USGS Publications**
Condon, L.A., Weisberg, P., 2016, Topographic Context of the Burn Edge Influences Postfire Recruitment of Arid Land Shrubs: Rangeland Ecology and Management, v. 69, no. 2, p. 129-133, https://doi.org/10.1016/j.rama.2015.09.002.
Dilts, T.E., Weisberg, P., Yang, J., Olson, T.J., Turner, P., Condon, L.A., 2012, Using Historical General Land Office Survey Notes to Quantify the Effects of Irrigated Agriculture on Land Cover Change in an Arid Lands Watershed: Annals of the Association of American Geographers, v. 102, no. 3, p. 531-548, https://doi.org/10.1080/00045608.2011.641479.
Condon, L.A., Weisberg, P., Chambers, J.C., 2011, Abiotic and biotic influences on Bromus tectorum invasion and Artemisia tridentata recovery after fire: International Journal of Wildland Fire, v. 20, p. 597-604, https://doi.org/10.1071/WF09082.
Yang, J., Dilts, T.E., Condon, L.A., Turner, P., Weisberg, P., 2011, Longitudinal- and transverse-scale environmental influences on riparian vegetation across multiple levels of ecological organization: Landscape Ecology, v. 26, p. 381-395, https://doi.org/10.1007/s10980-010-9565-z.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Can ruderal components of biocrust (mosses and cyanobacteria) be maintained under increasing threats of drought, grazing and feral horses?
Biological soil crusts (biocrusts) are a community of living organisms, like moss, lichen, and algae, covering soils in arid and semi-arid ecosystems, providing important ecological functions like carbon cycling and soil stabilization. Analyses show that biocrusts are negatively associated with the abundance of invasive annual grasses that are responsible for increasing fire across the Great Basin...
Morphogroups of Biocrusts Following Seasons of Grazing Near Boise, Idaho
The data were collected at Morley Nelson, Birds of Prey National Conservation Area (NCA) where known grazing regimes, including the season of grazing, have been in practice for the last 30 years. Surveyed plots were placed to account for intensity of grazing and to avoid confounding disturbances. Data were collected on the morphogroups of biological soil crusts (biocrusts) found within the NCA, an
Fire Response Effects, Biocrust, and Vascular Plant Abundance Following Wildfire near Boise, Idaho (October 2021)
Twenty quadrats within the burn perimeter of a September 2021 wildfire outside of Boise, Idaho were surveyed for the abundance of fire effects, biocrusts and vascular plants immediately post-fire. The fire was too small to be named. Char was measured as a proxy for fire intensity. Biocrusts were surveyed by morphogroup (crustose lichens, cup lichens, fruticose lichens, gelatinous lichens, short mo
10 Year Data for biocrust cover after fire management treatments
The data reflect surveys from 10-year sampling frames established as part of the Sagebrush Steppe Treatment Evaluation Project. The project tests fuel reduction treatments on the lichen and moss components of biocrusts across the sagebrush steppe.
Biological soil crust cover from the Taylor Grazing Act exclosures
Seven exclosures that were part of the original 28 Taylor Grazing Act exclosures across northern Nevada were surveyed for cover of biological soil crusts in May 2018. Surveys consisted of 15 quadrats both inside and outside of the exclosures. Quadrats were used to measure biocrust cover via point-intercept at 39 vertices within each quadrat. Cattle grazing outside of the exclosures was characteriz
Disturbance characteristics, vegetation and biocrust cover from the northern Great Basin (USA) 2012-2013
Fifteen fires from the Chronosequence dataset (see Knutson et al. 2014) were visited in 2012 and 2013 and surveyed for cover of lichens and mosses. Fires were selected to cover the range of average precipitation for each of three water years following fire, fire severity, time since fire, season of ignition, total acres burned and grazing intensity. Cattle grazing was characterized by distance fro
Science and Products
Season of grazing interacts with soil texture, selecting for associations of biocrust morphogroups
Livestock grazing, a widespread land use in semi-arid systems, is often placed in opposition to the perpetuation of biological soil crusts (“biocrusts”: lichens, mosses, and algal crusts including cyanobacteria) that live on the soil surface and provide ecosystem functions. The composition of biocrusts and vascular plants varies with climate, soils, and disturbance. In general, ruderal mosses and
Authors
Lea A. Condon, Roger Rosentreter, Kari E. Veblen, Peter S. Coates
Biological soil crusts are more prevalent in warmer and drier environments within the Great Basin ecoregion: Implications for managing annual grass invasion
Biological soil crusts (biocrusts) can thrive under environmental conditions that are stressful for vascular plants such as high temperatures and/or extremely low moisture availability. In these settings, and in the absence of disturbance, cover of biocrusts commonly exceeds cover of vascular plants. Arid landscapes are also typically slow to recover from disturbance and prone to altered vegetatio
Authors
Lea A. Condon, John B. Bradford, Peter S. Coates
Biocrusts indicators of livestock grazing effects on soil stability in sagebrush steppe: A case study from a long-term experiment in the northern Great Basin
Biocrusts are sensitive to changes in livestock grazing intensity in arid rangelands and may be useful indicators of ecosystem functions, particularly soil properties like soil stability, which may suggest the potential for soil erosion. We compared biocrust community composition and surface soil stability in a big sagebrush (Artemisia tridentata) steppe rangeland in the northwestern Great Basin i
Authors
Stella M. Copeland, Lea A. Condon, Roger Rosentreter, Jesse E.D. Miller, Maya Kahn-Abrams
Could biological soil crusts act as natural fire fuel breaks in the sagebrush steppe?
No abstract available.
Authors
Lea A. Condon, Douglas J. Shinneman, Roger Rosentreter, Peter S. Coates
Biological soil crusts in ecological restoration: Emerging research and perspectives
Drylands encompass over 40% of terrestrial ecosystems and face significant anthropogenic degradation causing a loss of ecosystem integrity, services, and deterioration of social‐ecological systems. To combat this degradation, some dryland restoration efforts have focused on the use of biological soil crusts (biocrusts): complex communities of cyanobacteria, algae, lichens, bryophytes, and other or
Authors
Anita Antoninka, Akasha M. Faist, Emilio Rodriguez-Caballero, Kristina E Young, V Bala Chaudhary, Lea A. Condon, David A. Pyke
Components and predictors of biological soil crusts vary at the regional vs. plant community scales
Although biological soil crusts (biocrusts) occur globally in arid and semi-arid environments, most of our knowledge of biocrust cover and ecology is from a relatively small number of locations worldwide. Some plant communities are known to have high cover of biocrusts, but the abundance of biocrusts is largely undocumented in most plant communities. Using a data driven approach, we identified 16
Authors
Lea A. Condon, David A. Pyke
Not all fuel‐reduction treatments degrade biocrusts: Herbicides cause mostly neutral to positive effects on cover of biocrusts
In response to increasing fire, fuel‐reduction treatments are being used to minimize large fire risk. Although biocrusts are associated with reduced cover of fire‐promoting, invasive grasses, the impact of fuel‐reduction treatments on biocrusts is poorly understood. We use data from a long‐term experiment, the Sagebrush Steppe Treatment Evaluation Project, testing the following fuel‐reduction trea
Authors
Lea A. Condon, Margaret L Gray
Passive restoration of vegetation and biological soil crusts following 80 years of exclusion from grazing across the Great Basin
Restoration targets for biological soil crusts are largely unknown. We surveyed seven 80‐year‐old grazing exclosures across northern Nevada for biocrusts to quantify reference conditions at relatively undisturbed sites. Exclosures were associated with the following plant communities: Wyoming big sagebrush, black sagebrush, and areas co‐dominated by winterfat and Wyoming big sagebrush. Cover of bio
Authors
Lea A. Condon, Nicole Pietrasiak, Roger Rosentreter, David A. Pyke
Hydroseeding tackifiers and dryland moss restoration potential
Tackifiers are long‐chain carbon compounds used for soil stabilization and hydroseeding and could provide a vehicle for biological soil crust restoration. We examined the sensitivity of two dryland mosses, Bryum argenteum and Syntrichia ruralis, to three common tackifiers ‐ guar, psyllium, and polyacrylamide (PAM) ‐ at 0.5x, 1.0x, and 2.0x of recommended (x) concentrations for erosion control and
Authors
W. Dillon Blankenship, Lea A. Condon, David A. Pyke
Resiliency of biological soil crusts and vascular plants varies among morphogroups with disturbance intensity
Background and aimsDisturbance affects the ability of organisms to persist on a site, and disturbance history acts as a filter of community composition. This is true for vascular plants and morphological groups of biocrusts, which respond differently to disturbance. Although functioning arid ecosystems include both groups, filtering of morphological groups of biocrusts has not previously been comp
Authors
Lea A. Condon, David A. Pyke
Fire and grazing influence site resistance to Bromus tectorum through their effects on shrub, bunchgrass and biocrust communities in the Great Basin (USA)
Shrubs, bunchgrasses and biological soil crusts (biocrusts) are believed to contribute to site resistance to plant invasions in the presence of cattle grazing. Although fire is a concomitant disturbance with grazing, little is known regarding their combined impacts on invasion resistance. We are the first to date to test the idea that biotic communities mediate the effects of disturbance on site r
Authors
Lea A. Condon, David A. Pyke
Filling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success
Biological soil crusts contribute to ecosystem functions and occupy space that could be available to invasive annual grasses. Given disturbances in the semiarid shrub steppe communities, we embarked on a set of studies to investigate restoration potential of mosses in sagebrush steppe ecosystems. We examined establishment and growth of two moss species common to the Great Basin, USA: Bryum argente
Authors
Lea Condon, David A. Pyke
Non-USGS Publications**
Condon, L.A., Weisberg, P., 2016, Topographic Context of the Burn Edge Influences Postfire Recruitment of Arid Land Shrubs: Rangeland Ecology and Management, v. 69, no. 2, p. 129-133, https://doi.org/10.1016/j.rama.2015.09.002.
Dilts, T.E., Weisberg, P., Yang, J., Olson, T.J., Turner, P., Condon, L.A., 2012, Using Historical General Land Office Survey Notes to Quantify the Effects of Irrigated Agriculture on Land Cover Change in an Arid Lands Watershed: Annals of the Association of American Geographers, v. 102, no. 3, p. 531-548, https://doi.org/10.1080/00045608.2011.641479.
Condon, L.A., Weisberg, P., Chambers, J.C., 2011, Abiotic and biotic influences on Bromus tectorum invasion and Artemisia tridentata recovery after fire: International Journal of Wildland Fire, v. 20, p. 597-604, https://doi.org/10.1071/WF09082.
Yang, J., Dilts, T.E., Condon, L.A., Turner, P., Weisberg, P., 2011, Longitudinal- and transverse-scale environmental influences on riparian vegetation across multiple levels of ecological organization: Landscape Ecology, v. 26, p. 381-395, https://doi.org/10.1007/s10980-010-9565-z.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Can ruderal components of biocrust (mosses and cyanobacteria) be maintained under increasing threats of drought, grazing and feral horses?
Biological soil crusts (biocrusts) are a community of living organisms, like moss, lichen, and algae, covering soils in arid and semi-arid ecosystems, providing important ecological functions like carbon cycling and soil stabilization. Analyses show that biocrusts are negatively associated with the abundance of invasive annual grasses that are responsible for increasing fire across the Great Basin...
Morphogroups of Biocrusts Following Seasons of Grazing Near Boise, Idaho
The data were collected at Morley Nelson, Birds of Prey National Conservation Area (NCA) where known grazing regimes, including the season of grazing, have been in practice for the last 30 years. Surveyed plots were placed to account for intensity of grazing and to avoid confounding disturbances. Data were collected on the morphogroups of biological soil crusts (biocrusts) found within the NCA, an
Fire Response Effects, Biocrust, and Vascular Plant Abundance Following Wildfire near Boise, Idaho (October 2021)
Twenty quadrats within the burn perimeter of a September 2021 wildfire outside of Boise, Idaho were surveyed for the abundance of fire effects, biocrusts and vascular plants immediately post-fire. The fire was too small to be named. Char was measured as a proxy for fire intensity. Biocrusts were surveyed by morphogroup (crustose lichens, cup lichens, fruticose lichens, gelatinous lichens, short mo
10 Year Data for biocrust cover after fire management treatments
The data reflect surveys from 10-year sampling frames established as part of the Sagebrush Steppe Treatment Evaluation Project. The project tests fuel reduction treatments on the lichen and moss components of biocrusts across the sagebrush steppe.
Biological soil crust cover from the Taylor Grazing Act exclosures
Seven exclosures that were part of the original 28 Taylor Grazing Act exclosures across northern Nevada were surveyed for cover of biological soil crusts in May 2018. Surveys consisted of 15 quadrats both inside and outside of the exclosures. Quadrats were used to measure biocrust cover via point-intercept at 39 vertices within each quadrat. Cattle grazing outside of the exclosures was characteriz
Disturbance characteristics, vegetation and biocrust cover from the northern Great Basin (USA) 2012-2013
Fifteen fires from the Chronosequence dataset (see Knutson et al. 2014) were visited in 2012 and 2013 and surveyed for cover of lichens and mosses. Fires were selected to cover the range of average precipitation for each of three water years following fire, fire severity, time since fire, season of ignition, total acres burned and grazing intensity. Cattle grazing was characterized by distance fro
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government