Susan K McIlroy
I am an Ecologist at the USGS Forest and Rangeland Ecosystem Science Center in Boise, Idaho.
My research focuses on vegetation response to fire and other disturbances in forest and rangeland ecosystems across the western United States. I conduct applied research that directly addresses conservation priorities on public lands.
Professional Experience
2010 - Present: Ecologist, U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, Idaho
2009 - 2010: Postdoctoral Researcher, University of California, Berkeley, California
Education and Certifications
Ph.D., Environmental Science, Policy, and Management, University of California, Berkeley
M.S., Land Rehabilitation, Montana State University
B.A., Sociology/Anthropology, Lewis and Clark College
Science and Products
Pinyon-Juniper Disturbance Effects on Wildlife
The Wildfire Trends Tool: A data visualization and analysis tool to meet land management needs and facilitate scientific inquiry
Vulnerability of Lower-Elevation Aspen Forests to Altered Fire and Climate Dynamics: Assessing Risks and Developing Actionable Science
Projecting the Effects of Climate Change on Aspen in the Central and Northern Rocky Mountains
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Cover, density, and biomass data from Sandberg bluegrass (Poa secunda) restoration treatments
Vegetation data from burned and unburned sagebrush communities in eastern Washington (2016)
Northern Nevada aspen (Populus tremuloides) data (2010-2011) (ver. 2.0, January 2024)
Fuels Database for Intact and Invaded Big Sagebrush (Artemisia tridentata) Ecological Sites
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Variable climate-growth relationships of quaking aspen (Populus tremuloides) among Sky Island mountain ranges in the Great Basin, Nevada, USA
Ecological effects of pinyon-juniper removal in the Western United States—A synthesis of scientific research, January 2014–March 2021
Fire frequency impacts soil properties and processes in sagebrush steppe ecosystems of the Columbia Basin
Disentangling the effects of multiple fires on spatially interspersed sagebrush (Artemisia spp.) communities
Post-fire aspen (Populus tremuloides) regeneration varies in response to winter precipitation across a regional climate gradient
Climate and disturbance influence self-sustaining stand dynamics of aspen (Populus tremuloides) near its range margin
Fuels guide and database for intact and invaded big sagebrush (Artemisia tridentata) ecological sites—User manual
Methodological considerations of terrestrial laser scanning for vegetation monitoring in the sagebrush steppe
Lidar aboveground vegetation biomass estimates in shrublands: Prediction, uncertainties and application to coarser scales
Estimating vegetation biomass and cover across large plots in shrub and grass dominated drylands using terrestrial lidar and machine learning
Identifying key climate and environmental factors affecting rates of post-fire big sagebrush (Artemisia tridentata) recovery in the northern Columbia Basin, USA
Landsat 8 and ICESat-2: Performance and potential synergies for quantifying dryland ecosystem vegetation cover and biomass
Non-USGS Publications**
**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.
Science and Products
- Science
Pinyon-Juniper Disturbance Effects on Wildlife
Researchers from the U.S. Geological Survey are reviewing, summarizing, and analyzing what is currently known about changes happening in pinyon-juniper ecosystems in the western U.S. in response to tree removal treatments. Although tree removal can help restore sagebrush ecosystems, these treatments also impact wildlife, wildfire fuels, and invasive plants. This project will help identify key...The Wildfire Trends Tool: A data visualization and analysis tool to meet land management needs and facilitate scientific inquiry
Fighting wildfires and reducing their negative effects on natural resources costs billions of dollars annually in the U.S. We will develop the Wildfire Trends Tool (WTT), a data visualization and analysis tool that will calculate and display wildfire trends and patterns for the western U.S. based on user-defined regions of interest, time periods, and ecosystem types. The WTT will be publicly availVulnerability of Lower-Elevation Aspen Forests to Altered Fire and Climate Dynamics: Assessing Risks and Developing Actionable Science
Aspen forests are considered keystone ecosystems, meaning that loss of aspen habitat would result in negative impacts to numerous plant and animal species. Aspen also provide important economic and social benefits, including drawing tourists, serving as potential fire breaks, improving local economies, and providing forage for wildlife and livestock. Ecologically-valuable aspen forests are consideProjecting the Effects of Climate Change on Aspen in the Central and Northern Rocky Mountains
Aspen is an environmentally, economically, and socially important species in the western U.S. It is typically the most abundant deciduous tree species in mountainous landscapes of the western U.S., providing food and habitat for a variety of wildlife, including black bear, deer, elk, moose, and numerous bird species. Aspen woodlands also provide high quality forage for livestock and draw tourists - Data
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Cover, density, and biomass data from Sandberg bluegrass (Poa secunda) restoration treatments
The dataset includes several measurements collected for two complementary phases of a Sandberg bluegrass restoration project. In the first phase of the project, percentage of vegetation and soil surface cover (e.g. soil, rock) were measured within each of 20 treatment plots (described in the following section) using the Line Point Intercept (LPI) method (Herrick et al. 2005) from 2019-2021. SandbeVegetation data from burned and unburned sagebrush communities in eastern Washington (2016)
The dataset includes several variables sampled across burned and unburned sagebrush communities located in an approximately 30 square kilometer portion of the Columbia Plateau Ecoregion in eastern Washington, USA. The study area is characterized by landforms interspersed at fine-scales, representative of the channeled scabland topography of the region (Baker 2009), including: "mounds," which are dNorthern Nevada aspen (Populus tremuloides) data (2010-2011) (ver. 2.0, January 2024)
This dataset contains two phases of research. The first dataset includes several variables that were sampled across aspen stands in the Santa Rosa, Ruby, and Jarbidge mountain ranges (Great Basin, Northern Nevada, USA) in 2010 and 2011. Across 101 aspen sites, several plot-level attributes were collected (e.g. elevation, slope, aspen stand type). For each plot, data describing live trees (both thoFuels Database for Intact and Invaded Big Sagebrush (Artemisia tridentata) Ecological Sites
The Fuels Guide and Database for Big Sagebrush Ecological Sites was developed as part of the Joint Fire Sciences Program project "Quantifying and predicting fuels and the effects of reduction treatments along successional and invasion gradients in sagebrush habitats" (Shinneman and others, 2015). The research was carried out by the U.S. Geological Survey (USGS) Forest and Rangeland Ecosystem Scien - Publications
If you are unable to access or download a product, email fresc_outreach@usgs.gov a request, including the full citation, or call (541) 750-1030.
Filter Total Items: 13Variable climate-growth relationships of quaking aspen (Populus tremuloides) among Sky Island mountain ranges in the Great Basin, Nevada, USA
The Great Basin is an arid province located in the interior western United States. The region encompasses millions of hectares and quaking aspen (Populus tremuloides Michx.) forests comprise a minor portion of the total area. However, montane aspen forests play a disproportionately large role in providing ecosystem services in the region, including water retention, biodiversity, wildlife habitat,AuthorsMartin Senfeldr, Douglas J. Shinneman, Susan McIlroy, Paul Rogers, R. Justin DeRoseEcological effects of pinyon-juniper removal in the Western United States—A synthesis of scientific research, January 2014–March 2021
Executive SummaryIncreasing density of pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands (hereinafter “pinyon-juniper”), as well as expansion of these woodlands into adjacent shrublands and grasslands, has altered ecosystem function and wildlife habitat across large areas of the interior western United States. Although there are many natural and human-caused drivers of woodland infillingAuthorsDouglas J. Shinneman, Susan K. McIlroy, Sharon A Poessel, Rosemary L. Downing, Tracey N. Johnson, Aaron C. Young, Todd E. KatznerFire frequency impacts soil properties and processes in sagebrush steppe ecosystems of the Columbia Basin
Increased fire frequency in semi-arid ecosystems can alter biochemical soil properties and soil processes that underpin ecosystem structure and functioning, thus threatening native plant communities and the species that rely on them. However, there is much uncertainty about the magnitude of change as soils are exposed to more fires, because soil recovery and changes in fire severity following a fiAuthorsLeslie Nichols, Douglas J. Shinneman, Susan McIlroy, Marie-Anne de GraaffDisentangling the effects of multiple fires on spatially interspersed sagebrush (Artemisia spp.) communities
QuestionsRelative to a landscape with a mosaic of two sagebrush community types and increasing fire frequency, we asked: (a) do vegetation characteristics vary significantly with number of times burned for each sagebrush community; (b) how do vegetation responses to different fire frequencies compare between the two sagebrush communities?LocationColumbia Plateau Ecoregion, Washington, USA.MethodsWAuthorsDouglas J. Shinneman, Susan McIlroy, Marie-Anne de GraaffPost-fire aspen (Populus tremuloides) regeneration varies in response to winter precipitation across a regional climate gradient
Altered climate and changing fire regimes are synergistically impacting forest communities globally, resulting in deviations from historical norms and creation of novel successional dynamics. These changes are particularly important when considering the stability of a keystone species such as quaking aspen (Populus tremuloides Michx.), which contributes critical ecosystem services across its broadAuthorsSusan McIlroy, Douglas J. ShinnemanClimate and disturbance influence self-sustaining stand dynamics of aspen (Populus tremuloides) near its range margin
Species that are primarily seral may form stable (self-sustaining) communities under certain disturbance regimes or environmental conditions, yet such populations may also be particularly vulnerable to ecological change. Aspen (Populus spp.) are generally considered seral throughout the northern hemisphere, including P. tremuloides, the most widely distributed tree species in North America. RecentAuthorsDouglas J. Shinneman, Susan McIlroyFuels guide and database for intact and invaded big sagebrush (Artemisia tridentata) ecological sites—User manual
The Fuels Guide and Database (FGD) is intended to provide fuel loading and vegetation information for big sagebrush (Artemisia tridentata) ecological sites in the Morley Nelson Snake River Birds of Prey National Conservation Area (hereinafter the NCA) in southern Idaho. Sagebrush ecosystems in the NCA and throughout much of the Great Basin are highly influenced by non-native plants that alter succAuthorsDouglas J. Shinneman, Justin L. Welty, Robert S. Arkle, David S. Pilliod, Nancy F. Glenn, Susan K. McIlroy, Anne S. HalfordMethodological considerations of terrestrial laser scanning for vegetation monitoring in the sagebrush steppe
Terrestrial laser scanning (TLS) provides fast collection of high-definition structural information, making it a valuable field instrument to many monitoring applications. A weakness of TLS collections, especially in vegetation, is the occurrence of unsampled regions in point clouds where the sensor’s line-of-sight is blocked by intervening material. This problem, referred to as occlusion, may beAuthorsKyle E. Anderson, Nancy Glenn, Lucas Spaete, Douglas J. Shinneman, David S. Pilliod, Robert Arkle, Susan McIlroy, DeWayne R. DerryberryLidar aboveground vegetation biomass estimates in shrublands: Prediction, uncertainties and application to coarser scales
Our study objectives were to model the aboveground biomass in a xeric shrub-steppe landscape with airborne light detection and ranging (Lidar) and explore the uncertainty associated with the models we created. We incorporated vegetation vertical structure information obtained from Lidar with ground-measured biomass data, allowing us to scale shrub biomass from small field sites (1 m subplots and 1AuthorsAihua Li, Shital Dhakal, Nancy F. Glenn, Luke P. Spaete, Douglas J. Shinneman, David S. Pilliod, Robert Arkle, Susan McIlroyEstimating vegetation biomass and cover across large plots in shrub and grass dominated drylands using terrestrial lidar and machine learning
Terrestrial laser scanning (TLS) has been shown to enable an efficient, precise, and non-destructive inventory of vegetation structure at ranges up to hundreds of meters. We developed a method that leverages TLS collections with machine learning techniques to model and map canopy cover and biomass of several classes of short-stature vegetation across large plots. We collected high-definition TLS sAuthorsKyle E. Anderson, Nancy F. Glenn, Lucas P. Spaete, Douglas J. Shinneman, David S. Pilliod, Robert Arkle, Susan McIlroy, DeWayne R. DerryberryIdentifying key climate and environmental factors affecting rates of post-fire big sagebrush (Artemisia tridentata) recovery in the northern Columbia Basin, USA
Sagebrush steppe of North America is considered highly imperilled, in part owing to increased fire frequency. Sagebrush ecosystems support numerous species, and it is important to understand those factors that affect rates of post-fire sagebrush recovery. We explored recovery of Wyoming big sagebrush (Artemisia tridentata ssp.wyomingensis) and basin big sagebrush (A. tridentata ssp. tridentata) coAuthorsDouglas J. Shinneman, Susan McIlroyLandsat 8 and ICESat-2: Performance and potential synergies for quantifying dryland ecosystem vegetation cover and biomass
The Landsat 8 mission provides new opportunities for quantifying the distribution of above-ground carbon at moderate spatial resolution across the globe, and in particular drylands. Furthermore, coupled with structural information from space-based and airborne laser altimetry, Landsat 8 provides powerful capabilities for large-area, long-term studies that quantify temporal and spatial changes in aAuthorsNancy F. Glenn, Amy Neuenschwander, Lee A. Vierling, Lucas Spaete, Aihua Li, Douglas J. Shinneman, David S. Pilliod, Robert Arkle, Susan McIlroyNon-USGS Publications**
McIlroy, S.K., Montagne, C., Jones, C.A., McGlynn, B.L., 2008, Identifying linkages between land use, geomorphology, and aquatic habitat in a mixed-use watershed: Environmental Management, v. 42, no. 5, p. 867-876, https://doi.org/10.1007/s00267-008-9166-7.McIlroy, S.K., Allen-Diaz, B.H., Berg, A.C., 2011, Using digital photography to examine grazing in montane meadows: Rangeland Ecology and Management, v. 64, no. 2, p. 187-195.McIlroy, S.K., Allen-Diaz, B.H., 2012, Plant community distribution along water table and grazing gradients in montane meadows of the Sierra Nevada Range (California, USA): Wetlands Ecology Management, v. 20, no. 4, p. 287-296, https://doi.org/10.1007/s11273-012-9253-7.McIlroy, S.K., Lind, A.J., Allen-Diaz, B.H., Roche, L.M., Frost, W.E., Grasso, R.L., Tate, K.W., 2013, Determining the effects of cattle grazing treatments on Yosemite toads (Anaxyrus [=Bufo] canorus) in montane meadows: PLOS ONE, v. 8, no. 11, p. e79263, https://doi.org/10.1371/journal.pone.0079263.**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.
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