Cameron L Aldridge, PhD
Dr. Cameron Aldridge is a research ecologist at the Fort Collins Science Center. Dr. Aldridge's work focuses on the conservation and management of sage-grouse and their habitats.
Dr. Cameron Aldridge is a Research Ecologist with the US Geological Survey, based at the Fort Collins Science Center, who works in collaboration with the Natural Resource Ecology Lab at Colorado State University. He is also an Affiliate Research Scientist at NREL and an Affiliate Professor with ESS and GDPE.
His research is diverse, but he is best recognized as one of the foremost sage-grouse ecologists in the world. He has a large research program focused on understanding the conservation and management of Greater and Gunnison Sage-grouse and their habitats. His research team includes both undergraduate and graduate students, research associates, post-doctoral fellows, and research scientists, all of which collaborate to understand why sage-grouse populations have declined, what major factors affect resource conditions and quality for sage-grouse, what drives population dynamics. The Aldridge Lab works closely on these issues with state and federal partners, as well as NGOs, conservation groups and industry.
More broadly, research in the Aldridge Lab involves understanding animal-habitat relationships, with an emphasis on conservation ecology and population demography. Researchers in the lab are addressing the effects of energy development, land-use change, and climate change on conserving wildlife populations, their habitats, and the ecosystems they inhabit. Species that we are currently studying include songbirds and small mammals, snakes and lizards, and grouse, such as white-tailed ptarmigan and sage-grouse. We also work with plant communities and exotic invasive plants, understanding how external drivers such as climate, grazing and energy development affect plant communities. We work across spatial scales, and use statistical and empirical modeling to answer these research and conservation questions, most of which have direct applications for conservation and management of the species and their habitats. Most of the research has direct applications for conservation and management of the species, most notably sage-grouse, and their habitats.
Professional Experience
August 2023-Present Branch Chief, and Research Supervisory Ecologist, Ecosystem and Landscape Dynamic Research Branch, US Geological Survey, Fort Collins Science Center, Fort Collins, Colorado.
March 2022-Present Acting Branch Chief, Ecosystem and Landscape Dynamic Research Branch, US Geological Survey, Fort Collins Science Center, Fort Collins, Colorado
Feb. 2020-Present Research Ecologist, US Geological Survey, Fort Collins Science Center, Fort Collins, Colorado
Feb. 2020-Present Affiliate Research Scientist, Natural Resource Ecology Laboratory, Colorado State University
Feb. 2020-Present Affiliate Professor, Department of Ecosystem Science and Sustainability and Graduate Degree Program in Ecology, Colorado State University
Jan. 2017-20 Finance Committee Member for the Natural Resource Ecology Laboratory, Colorado State University
July 2015-20 Associate Professor with Tenure, Department of Ecosystem Science and Sustainability, Colorado State University
July 2015-Present Research Scientist III, Natural Resource Ecology Laboratory, Colorado State University & U.S. Geological Survey, FORT Science Center, Fort Collins, Colorado
Aug. 2014-16 Executive Committee Member, Graduate Degree Program in Ecology, Colorado State University
Jan. 2012-18 Graduate Program Advisor for the Department of Ecosystem Science and Sustainability, Natural Resource Ecology Laboratory, Colorado State University.
Aug. 2010 Assistant Professor, Department of Ecosystem Science and Sustainability, Colorado State University.
July 2009 Research Scientist II, Natural Resource Ecology Laboratory, Colorado State University & U.S. Geological Survey, FORT Science Center, Fort Collins, Colorado.
Feb. 2007-Present Faculty Member, Graduate Degree Program in Ecology (GDPE), Colorado State University
Feb. 2007-11 Joint Faculty Member, Department of Fish, Wildlife, and Conservation Biology, Colorado State University
Oct. 2006 Research Scientist, Natural Resource Ecology Laboratory, Colorado State University & U.S. Geological Survey, FORT Science Center, Fort Collins, Colorado.
Education and Certifications
2005 - 2006 Post Doctoral Research Fellow, Natural Resource Ecology Laboratory, Colorado State University & U.S. Geological Survey, FORT Science Center, Fort Collins, CO.
2000 - 2005 Doctorate of Philosophy in Ecology, Department of Biological Sciences, University of Alberta, Edmonton, Alberta.
1998 - 2000 Master of Science in Biology, Department of Biology, University of Regina, Regina, Saskatchewan.
1991 - 1996 Bachelor of Science double major in Ecology and Zoology, Department of Biological Sciences, University of Calgary, Calgary, Alberta.
Science and Products
Prioritizing restoration and conservation of sagebrush ecosystems in northwestern Colorado
Assessing the Proliferation, Connectivity, and Consequences of Invasive Fine Fuels on the Sagebrush Biome
Prioritizing sagebrush protection and restoration within the upper Colorado River Basin
Prioritizing conifer removal for multi-species outcomes
Prioritizing restoration and conservation of Wyoming’s sagebrush ecosystems for wildlife and sagebrush connectivity
Assessing invasive annual grass treatment efficacy across the sagebrush biome
Creating range-wide predictive maps of Greater Sage-Grouse seasonal habitats
Understanding Population Trends for the Gunnison Sage-Grouse to Inform Adaptive Management
Predicting Recovery of Sagebrush Ecosystems Across the Sage-grouse Range from Remotely Sensed Vegetation Data
Wild horse and livestock influences on vegetation and wildlife in sagebrush ecosystems: Implications for refining and validating Appropriate Management Level (AML)
Using simulation models to project and evaluate post-fire success in restoring sage-grouse habitat over large landscapes
Simulating the influence of sagebrush restoration on post-fire sage-grouse population recovery
Greater sage-grouse genetic warning system, western United States (ver 1.1, January 2023)
Predicted Pinyon Jay (Gymnorhinus cyanocephalus) densities across the western United States, 2008-2020
Sagebrush (Artemisia spp.) scale of effect for Greater Sage-grouse (Centrocercus urophasianus) population trends in southwest Wyoming, USA 2003-2019
Trends and a Targeted Annual Warning System for Greater Sage-Grouse in the Western United States (ver. 3.0, February 2024)
U.S. range-wide spatial prediction layers of lek persistence probabilities for greater sage-grouse
Hierarchically nested and biologically relevant range-wide monitoring frameworks for greater sage-grouse, western United States
Sagebrush Restoration Following Fire Disturbance in the Virginia Mountains, Nevada (2018)
Greater sage-grouse population structure and connectivity data to inform the development of hierarchical population units (western United States)
Gunnison sage-grouse habitat suitability of six satellite populations in southwestern Colorado: San Miguel, Crawford, Pinon Mesa, Dove Creek, Cerro Summit-Cimarron-Sims, and Poncha Pass
Database of invasive annual grass spatial products for the western United States January 2010 to February 2021
Sagebrush recovery analyzed with a dynamic reference approach in southwestern Wyoming, USA 1985-2018
Spatial layers generated by the Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET) applied in Southern Wyoming
Range-wide population trend analysis for greater sage-grouse (Centrocercus urophasianus)—Updated 1960–2021
Spatial scale selection for informing species conservation in a changing landscape
A genetic warning system for a hierarchically structured wildlife monitoring framework
A regionally varying habitat model to inform management for greater sage-grouse persistence across their range
Defining biologically relevant and hierarchically nested population units to inform wildlife management
Potential cheatgrass abundance within lightly invaded areas of the Great Basin
Defining fine-scaled population structure among continuously distributed populations
Prairie grouse and wind energy: The state of the science and implications for risk assessment
Targeting sagebrush (Artemisia spp.) restoration following wildfire with Greater Sage-Grouse (Centrocercus urophasianus) nest selection and survival models
Scale-dependent influence of the sagebrush community on genetic connectivity of the sagebrush obligate Gunnison sage-grouse
Balancing model generality and specificity in management-focused habitat selection models for Gunnison sage-grouse
Bridging the gap between spatial modeling and management of invasive annual grasses in the imperiled sagebrush biome
Science and Products
- Science
Filter Total Items: 58
Prioritizing restoration and conservation of sagebrush ecosystems in northwestern Colorado
We are working with Colorado Parks and Wildlife (CPW) to pilot an expansion of the Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET; Duchardt et al. 2021) across northwestern Colorado. We are in the initial phase of a two-phase project where we are leveraging existing data resources to provide customized scenarios that directly guide landscape-scale conservation delivery by CPW. This...Assessing the Proliferation, Connectivity, and Consequences of Invasive Fine Fuels on the Sagebrush Biome
Invasive annual grasses can replace native vegetation and alter fire behavior, impacting a range of habitats and species. A team of researchers from the U.S. Geological Survey, Colorado State University, the Bureau of Land Management, and the U.S. Fish and Wildlife Service are working to identify factors that influence changes in the distribution and abundance of invasive annual grasses (IAGs)...Prioritizing sagebrush protection and restoration within the upper Colorado River Basin
Arid shrublands of western North America face growing threats from disturbances such as wildfire, drought, and invasive species. These threats are increasingly altering the sagebrush ( Artemisia species) biome and degrading habitat for species of conservation concern such as greater sage-grouse ( Centrocercus urophasianus ). Effective management and restoration are needed to slow or reverse these...Prioritizing conifer removal for multi-species outcomes
Wildlife management is frequently conducted to benefit a single species, despite evidence that suggests such an approach often fails to adequately address the needs of other species within a region. Managing for multiple species’ habitat requirements is even more critical when large scale habitat management efforts change vegetation conditions at the landscape scale, or when management occurs at...Prioritizing restoration and conservation of Wyoming’s sagebrush ecosystems for wildlife and sagebrush connectivity
To support strategic ecosystem management across the imperiled sagebrush steppe in Wyoming, USA, we developed an extension of the Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET). Our expanded tool leverages emerging spatial data resources to provide a structured but customizable set of scenarios that can guide landscape-scale planning efforts by prioritizing conservation and...Assessing invasive annual grass treatment efficacy across the sagebrush biome
We are using existing datasets that span broad spatial and temporal extents to model the efficacy of invasive annual grass treatments across the sagebrush biome and the influence of environmental factors on their success. The models we develop will be used to generate maps of predicted treatment efficacy across the biome, which will be integrated into the Land Treatment Exploration Tool for land...Creating range-wide predictive maps of Greater Sage-Grouse seasonal habitats
Through a collaborative effort with multiple state and federal agencies, university researchers, and individual stakeholders, we are producing a set of predictive seasonal habitat maps for greater sage-grouse ( Centrocercus urophasianus ) spanning the entirety of the species’ U.S. distribution. This is the largest habitat modeling effort of its kind for the species and uses a large, compiled...Understanding Population Trends for the Gunnison Sage-Grouse to Inform Adaptive Management
In partnership with the Bureau of Land Management and Colorado Parks and Wildlife, scientists from USGS Fort Collins Science Center and Western Ecological Research Center are applying a hierarchical monitoring framework to Gunnison sage-grouse ( Centrocercus minimus ) to evaluate population trends and inform adaptive management.Predicting Recovery of Sagebrush Ecosystems Across the Sage-grouse Range from Remotely Sensed Vegetation Data
USGS researchers are using remote-sensing and other broadscale datasets to study and predict recovery of sagebrush across the sage-grouse range, assessing influence of disturbance, restoration treatments, soil moisture, and other ecological conditions on trends in sagebrush cover. The results will be used to inform conservation prioritization models, economic analyses, climate change projections...Wild horse and livestock influences on vegetation and wildlife in sagebrush ecosystems: Implications for refining and validating Appropriate Management Level (AML)
USGS researchers are conducting a comprehensive study of wild horse and livestock records across the greater sage-grouse range to investigate impacts on vegetation and wildlife (specifically, sage-grouse and songbirds). Researchers will use these results to evaluate Appropriate Management Levels for wild horse and burros, and projections of vegetation productivity under a changing climate.Using simulation models to project and evaluate post-fire success in restoring sage-grouse habitat over large landscapes
Wildfires are increasingly destroying wildlife habitat in sagebrush ( Artemisia species) ecosystems, and managers need approaches to scope the pace and degree to which post-fire restoration actions can re-create habitat in dynamic landscapes. Sagebrush recovery takes a long time, and it can be difficult to anticipate restoration outcomes over large, diverse landscapes that have experienced decades...Simulating the influence of sagebrush restoration on post-fire sage-grouse population recovery
Increased wildfire-induced loss of sagebrush in North American shrublands are outpacing natural recovery and leading to substantial habitat loss for sagebrush-obligate species like sage-grouse. Transplanting sagebrush ( Artemisia species) is a possible strategy for revegetating burned areas, but little is known about sage-grouse or other wildlife responses to restoration strategies. - Data
Filter Total Items: 32
Greater sage-grouse genetic warning system, western United States (ver 1.1, January 2023)
Genetic variation is a well-known indicator of population fitness yet is not typically included in monitoring programs for sensitive species. Additionally, most programs monitor populations at one scale, which can lead to potential mismatches with ecological processes critical to species’ conservation. Recently developed methods generating hierarchically nested population units (i.e., clusters ofPredicted Pinyon Jay (Gymnorhinus cyanocephalus) densities across the western United States, 2008-2020
Management intended to benefit a target species may also affect non-target species that co-occur over space and time. Pinyon jay (Gymnorhinus cyanocephalus) populations experienced long-term declines and rely on habitat that could be lost to conifer removal programs for greater sage-grouse (Centrocercus urophasianus). Using 13 years of point count data (2008-2020) collected across the western UnitSagebrush (Artemisia spp.) scale of effect for Greater Sage-grouse (Centrocercus urophasianus) population trends in southwest Wyoming, USA 2003-2019
The distance within which populations respond to features in a landscape (scale of effect) can indicate how disturbance and management may affect wildlife. Using annual counts of male Greater Sage-grouse (Centrocercus urophasianus) attending 584 leks in southwest Wyoming (2003-2019) and estimates of sagebrush cover from the Rangeland Condition Monitoring Assessment and Projection (RCMAP), we usedTrends and a Targeted Annual Warning System for Greater Sage-Grouse in the Western United States (ver. 3.0, February 2024)
Greater sage-grouse (Centrocercus urophasianus) are at the center of state and national land use policies largely because of their unique life-history traits as an ecological indicator for health of sagebrush ecosystems. These data represent an updated population trend analysis and Targeted Annual Warning System (TAWS) for state and federal land and wildlife managers to use best-available scienceU.S. range-wide spatial prediction layers of lek persistence probabilities for greater sage-grouse
This dataset contains two predictive lek (breeding site) persistence raster layers covering the U.S. greater sage-grouse distribution. In the United States, locations where males display and breed with females (i.e., leks) are often monitored annually by state wildlife agencies, providing valuable information on the persistence of birds in the surrounding areas. A U.S. range-wide lek database wasHierarchically nested and biologically relevant range-wide monitoring frameworks for greater sage-grouse, western United States
We produced 13 hierarchically nested cluster levels that reflect the results from developing a hierarchical monitoring framework for greater sage-grouse across the western United States. Polygons (clusters) within each cluster level group a population of sage-grouse leks (sage-grouse breeding grounds) and each level increasingly groups lek clusters from previous levels. We developed the hierarchicSagebrush Restoration Following Fire Disturbance in the Virginia Mountains, Nevada (2018)
We developed a framework that strategically targets burned areas for restoration actions (e.g., seeding or planting sagebrush) that have the greatest potential to positively benefit Greater Sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) populations through time. Specifically, we estimated sagebrush (Artemisia Spp.) recovery following wildfire and risk of non-native annual grass invGreater sage-grouse population structure and connectivity data to inform the development of hierarchical population units (western United States)
We present five hierarchical demarcations of greater sage-grouse population structure, representing the spatial structure of populations which can exist due to differences in dispersal abilities, landscape configurations, and mating behavior. These demarcations represent Thiessen polygons of graph constructs (least-cost path [LCP] minimum spanning trees [MST; LCP-MST]) representing greater sage-grGunnison sage-grouse habitat suitability of six satellite populations in southwestern Colorado: San Miguel, Crawford, Pinon Mesa, Dove Creek, Cerro Summit-Cimarron-Sims, and Poncha Pass
We developed habitat selection models for Gunnison sage-grouse (Centrocercus minimus), a threatened species under the U.S. Endangered Species Act. We followed a management-centric modeling approach that sought to balance the need to evaluate the consistency of key habitat conditions and improvement actions across multiple, distinct populations, while allowing context-specific environmental variablDatabase of invasive annual grass spatial products for the western United States January 2010 to February 2021
Invasive annual grasses (IAGs) present a persistent challenge for the ecological management of rangelands, particularly the imperiled sagebrush biome in western North America. Cheatgrass (Bromus tectorum), medusahead (Taeniatherum caput-medusae), and Ventenata spp. are spreading across sagebrush rangelands and already occupy at least 200,000 kilometers squared (km sq.) of the intermountain west. TSagebrush recovery analyzed with a dynamic reference approach in southwestern Wyoming, USA 1985-2018
Identifying ecologically relevant reference sites is important for evaluating ecosystem recovery, but the relevance of references that are temporally static is unclear in the context of vast landscapes with disturbance and environmental contexts varying over space and time. This question is pertinent for landscapes dominated by sagebrush (Artemisia spp.) which face a suite of threats from disturbaSpatial layers generated by the Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET) applied in Southern Wyoming
All data layers included in this data release were created using the Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET) tool, which relies on spatial inputs on species distributions and likelihood of restoration success to select parcels for sagebrush restoration. The PReSET is a workflow that relies on the prioritizr package in program R to identify parcels for effective and meaningfu - Multimedia
- Publications
Filter Total Items: 120
Range-wide population trend analysis for greater sage-grouse (Centrocercus urophasianus)—Updated 1960–2021
Greater sage-grouse (Centrocercus urophasianus) are at the center of state and national land use policies largely because of their unique life-history traits as an ecological indicator for health of sagebrush ecosystems. This updated population trend analysis provides state and federal land and wildlife managers with best-available science to help guide current management and conservation plans aiAuthorsPeter S. Coates, Brian G. Prochazka, Cameron L. Aldridge, Michael S. O'Donnell, David R. Edmunds, Adrian P. Monroe, Steve E. Hanser, Lief A. Wiechman, Michael P. ChenailleSpatial scale selection for informing species conservation in a changing landscape
Identifying the relevant spatial scale at which species respond to features in a landscape (scale of effect) is a pressing research need as managers work to reduce biodiversity loss amid a variety of environmental challenges. Until recently, researchers often evaluated a subset of potential scales of effect inferred from previous studies in other locations, often based on different biological respAuthorsAdrian P. Monroe, Julie A. Heinrichs, Ashley Lorraine Whipple, Michael O'Donnell, David R. Edmunds, Cameron L. AldridgeA genetic warning system for a hierarchically structured wildlife monitoring framework
Genetic variation is a well-known indicator of population fitness yet is not typically included in monitoring programs for sensitive species. Additionally, most programs monitor populations at one scale, which can lead to potential mismatches with ecological processes critical to species' conservation. Recently developed methods generating hierarchically nested population units (i.e., clusters ofAuthorsShawna J Zimmerman, Cameron L. Aldridge, Michael O'Donnell, David R. Edmunds, Peter S. Coates, Brian G. Prochazka, Jennifer A. Fike, Todd B. Cross, Bradley C. Fedy, Sara J. Oyler-McCanceA regionally varying habitat model to inform management for greater sage-grouse persistence across their range
Identifying habitat needs for species with large distributions is challenging because species-habitat associations may vary across scales and regions (spatial nonstationarity). Furthermore, management efforts often cross jurisdictional boundaries, complicating the development of cohesive conservation strategies among management entities. The greater sage-grouse (Centrocercus urophasianus) is a rapAuthorsGregory T. Wann, Nathan D. Van Schmidt, Jessica E. Shyvers, Bryan C. Tarbox, Megan M. McLachlan, Michael O'Donnell, Anthony J Titolo, Peter S. Coates, David R. Edmunds, Julie A. Heinrichs, Adrian P. Monroe, Cameron L. AldridgeDefining biologically relevant and hierarchically nested population units to inform wildlife management
Wildlife populations are increasingly affected by natural and anthropogenic changes that negatively alter biotic and abiotic processes at multiple spatiotemporal scales and therefore require increased wildlife management and conservation efforts. However, wildlife management boundaries frequently lack biological context and mechanisms to assess demographic data across the multiple spatiotemporal sAuthorsMichael O'Donnell, David R. Edmunds, Cameron L. Aldridge, Julie A. Heinrichs, Adrian P. Monroe, Peter S. Coates, Brian G. Prochazka, Steve E. Hanser, Lief A. WiechmanPotential cheatgrass abundance within lightly invaded areas of the Great Basin
ContextAnticipating where an invasive species could become abundant can help guide prevention and control efforts aimed at reducing invasion impacts. Information on potential abundance can be combined with information on the current status of an invasion to guide management towards currently uninvaded locations where the threat of invasion is high.ObjectivesWe aimed to support management by develoAuthorsHelen Sofaer, Catherine S. Jarnevich, Erin K. Buchholtz, Brian S. Cade, John T. Abatzoglou, Cameron L. Aldridge, Patrick Comer, Daniel Manier, Lauren E. Parker, Julie A. HeinrichsDefining fine-scaled population structure among continuously distributed populations
Understanding wildlife population structure and connectivity can help managers identify conservation strategies, as structure can facilitate the study of population changes and habitat connectivity can provide information on dispersal and biodiversity. To facilitate the use of wildlife monitoring data for improved adaptive management, we developed a novel approach to define hierarchical tiers (mulAuthorsMichael O'Donnell, David R. Edmunds, Cameron L. Aldridge, Julie A. Heinrichs, Adrian P. Monroe, Peter S. Coates, Brian G. Prochazka, Steve E. Hanser, Lief A. WiechmanPrairie grouse and wind energy: The state of the science and implications for risk assessment
How to shape the anticipated build-out of industrial-scale renewable energy in a way that minimizes risk to wildlife remains contentious. This challenge is well-illustrated in the grasslands and shrub-steppe of North America. Here, several endemic species of grouse are the focus of intensive, long-term conservation action by a host of governmental and non-governmental entities, many of whom are noAuthorsJohn D. Lloyd, Cameron L. Aldridge, Taber D. Allison, Chad W. LeBeau, Lance B. McNew, Virginia L. WinderTargeting sagebrush (Artemisia spp.) restoration following wildfire with Greater Sage-Grouse (Centrocercus urophasianus) nest selection and survival models
Unprecedented conservation efforts for sagebrush (Artemisia spp.) ecosystems across the western United States have been catalyzed by risks from escalated wildfire activity that reduces habitat for sagebrush-obligate species such as Greater Sage-Grouse (Centrocercus urophasianus). However, post-fire restoration is challenged by spatial variation in ecosystem processes influencing resilience to distAuthorsCali L. Roth, Shawn T. O'Neil, Peter S. Coates, Mark A. Ricca, David A. Pyke, Cameron L. Aldridge, Julie A. Heinrichs, Shawn P. Espinosa, David J. DelehantyScale-dependent influence of the sagebrush community on genetic connectivity of the sagebrush obligate Gunnison sage-grouse
Habitat fragmentation and degradation impacts an organism's ability to navigate the landscape, ultimately resulting in decreased gene flow and increased extinction risk. Understanding how landscape composition impacts gene flow (i.e., connectivity) and interacts with scale is essential to conservation decision-making. We used a landscape genetics approach implementing a recently developed statistiAuthorsShawna J Zimmerman, Cameron L. Aldridge, Mevin B. Hooten, Sara J. Oyler-McCanceBalancing model generality and specificity in management-focused habitat selection models for Gunnison sage-grouse
Identifying, protecting, and restoring habitats for declining wildlife populations is foundational to conservation and recovery planning for any species at risk of decline. Resource selection analysis is a key tool to assess habitat and prescribe management actions. Yet, it can be challenging to map suitable resource conditions across a wide range of ecological contexts and use the resulting modelAuthorsDorothy Saher, Michael O'Donnell, Cameron L. Aldridge, Julie A. HeinrichsBridging the gap between spatial modeling and management of invasive annual grasses in the imperiled sagebrush biome
Invasions of native plant communities by non-native species present major challenges for ecosystem management and conservation. Invasive annual grasses such as cheatgrass, medusahead, and ventenata are pervasive and continue to expand their distributions across imperiled sagebrush-steppe communities of the western United States. These invasive grasses alter native plant communities, ecosystem funcAuthorsBryan C. Tarbox, Nathan D. Van Schmidt, Jessica E. Shyvers, D. Joanne Saher, Julie A. Heinrichs, Cameron L. Aldridge - Software
- News