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.
Science and Products
Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET): A USGS-facilitated Decision-support Tool for Sagebrush Ecosystem Conservation and Restoration Actions
Invasive Annual Grass (IAG) Spatial Dataset Compilation and Synthesis
Optimization of Management Actions for Restoration Success and Wildlife Populations
Contributions to the development of the Western Association of Fish and Wildlife Agencies Sagebrush Conservation Strategy
Genomic Scans for Local Adaptation in Greater Sage-Grouse
Incorporating Genetic Information Into Population Monitoring and Assessment Tools
Informing the Habitat Assessment Framework Process—An Assessment to Understand Habitat Patch Composition and Configuration Requirements for Range-Wide Sage-Grouse Persistence
Economic Implications of Sagebrush Treatment and Restoration Practices Across the Great Basin and Wyoming
Modeling Habitat-Relationships of Pinyon-Juniper and Sagebrush Associated Bird Species to Inform Conifer Removal
Forecasting the Spatiotemporal Dynamics of Sagebrush in Wyoming Under a Changing Climate
Defining Multi-Scaled Functional Landscape Connectivity for the Sagebrush Biome to Support Management and Conservation Planning of Multiple Species
Greater Sage-Grouse and Mule Deer Population Viability Analysis Across Scales
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 (1960-2021)
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
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
Predicted (1989-2015) and forecasted (2015-2114) estimates for rate of change and recovery of sagebrush (Artemisia spp.) following energy development in southwestern Wyoming, USA (ver. 2.0, January 2021)
Sample collection information and SNP data for Gunnison Sage-grouse across the species range generated in the Molecular Ecology Lab during 2015-2018
Sample collection information and microsatellite data for Gunnison sage-grouse pre and post translocation
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
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
Compendium to invasive annual grass spatial products for the western United States, January 2010-February 2021
A user guide to selecting invasive annual grass spatial products for the western United States
popcluster: hierarchical population monitoring frameworks, Version 2.0.0
Spatial scale selection for greater sage-grouse population trends, Version 1.0.0
grsg_lekdb: Compiling and standardizing greater sage-grouse lek databases, version 1.1.0
lcp_centrality: Defining least-cost paths and graph theory centrality measures
grsg_lekdb: Compiling and standardizing greater sage-grouse lek databases
popcluster: Developing Hierarchical Population Monitoring Frameworks for mobile species with high site fidelity
Science and Products
- Science
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Prioritizing Restoration of Sagebrush Ecosystems Tool (PReSET): A USGS-facilitated Decision-support Tool for Sagebrush Ecosystem Conservation and Restoration Actions
Sagebrush ecosystems, one of the most imperiled in North America, face continued and widespread degradation due to multiple factors, including climate change, invasive species, and increased human development. Effective sagebrush management must consider how to best conserve and restore habitats to stem the decline of species that rely on them, especially given limited conservation resources. To...Invasive Annual Grass (IAG) Spatial Dataset Compilation and Synthesis
USGS is working closely with partners in the Bureau of Land Management (BLM), U.S. Fish and Wildlife Service (USFWS), and the Intermountain West Joint Venture (IMJV) to collect and summarize spatial datasets that describe measurable aspects of invasive annual grasses (e.g., biomass or presence) across the western United Stated and beyond. The products developed through this project provide...Optimization of Management Actions for Restoration Success and Wildlife Populations
USGS researchers, in collaboration with the Wyoming Landscape Conservation Initiative and other partners, are developing a statistically based prioritization tool that will aid agencies in their management decisions.Contributions to the development of the Western Association of Fish and Wildlife Agencies Sagebrush Conservation Strategy
USGS scientists are contributing to the development of the Western Association of Fish and Wildlife Agencies Sagebrush Conservation Strategy, a strategy intended to provide guidance so that efforts to conserve the iconic greater sage-grouse can be expanded to the entire sagebrush biome to benefit the people and wildlife that depend on it.Genomic Scans for Local Adaptation in Greater Sage-Grouse
USGS scientists are identifying local adaptation in sage-grouse by modeling allelic variation at large numbers of single-nucleotide polymorphisms (SNPs) in relation to environmental and climate variables.Incorporating Genetic Information Into Population Monitoring and Assessment Tools
To better inform and prioritize management decisions for greater sage-grouse, USGS scientists are leading a range-wide population trend assessment for sage-grouse.Informing the Habitat Assessment Framework Process—An Assessment to Understand Habitat Patch Composition and Configuration Requirements for Range-Wide Sage-Grouse Persistence
USGS scientists are developing multiple products to directly inform the Bureau of Land Management's Sage-grouse Habitat Assessment Framework process.Economic Implications of Sagebrush Treatment and Restoration Practices Across the Great Basin and Wyoming
USGS and Colorado State University researchers are conducting analyses and predictions of sagebrush recovery in the Great Basin and Wyoming and assess the role of weather, soils, and reseeding treatments.Modeling Habitat-Relationships of Pinyon-Juniper and Sagebrush Associated Bird Species to Inform Conifer Removal
Management agencies are increasingly restoring sagebrush systems by removing conifers. These treatments likely result in mixed effects for wildlife species, and wildlife response may vary across the landscape. Declining sagebrush and pinyon-juniper associated bird populations highlight a clear need for tools that can help guide conifer management across the sagebrush ecosystem.Forecasting the Spatiotemporal Dynamics of Sagebrush in Wyoming Under a Changing Climate
Prioritizing landscapes for sage-grouse habitat conservation is complicated by long-term changes in climate.Defining Multi-Scaled Functional Landscape Connectivity for the Sagebrush Biome to Support Management and Conservation Planning of Multiple Species
USGS and Colorado State University scientists are modelling multispecies connectivity through intact and disturbed areas of the sagebrush landscape.Greater Sage-Grouse and Mule Deer Population Viability Analysis Across Scales
USGS and Colorado State University scientists will use data about sage-grouse and mule deer population data across Wyoming to evaluate the effectiveness of disturbance thresholds and investigate the efficacy of other disturbance metrics. - Data
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Sagebrush (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 (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. 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 hierarchicGreater 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 meaningfuPredicted (1989-2015) and forecasted (2015-2114) estimates for rate of change and recovery of sagebrush (Artemisia spp.) following energy development in southwestern Wyoming, USA (ver. 2.0, January 2021)
In 'Predicted (1989-2015) and forecasted (2015-2114) rate of change and recovery of sagebrush (Artemisia spp.) following energy development in southwestern Wyoming, USA (ver. 2.0, January 2021)', we provide spatially- and temporally-explicit maps of predictions for the rate of change and time to recovery and percent recovery of sagebrush cover after 100 years (Monroe et al. 2020). The rasters begiSample collection information and SNP data for Gunnison Sage-grouse across the species range generated in the Molecular Ecology Lab during 2015-2018
This dataset contains sample collection information and SNP genotypes for populations of Gunnison Sage-grouse across the species' range. This data was collected in order to examine patterns of adaptive genetic variation in Gunnison Sage-grouse. The data is archived in GenBank at the following URL https://www.ncbi.nlm.nih.gov/bioproject/517770.Sample collection information and microsatellite data for Gunnison sage-grouse pre and post translocation
Maintenance of genetic diversity is important for conserving species, especially those with fragmented habitats and/or ranges. In the absence of natural dispersal, translocation can be used to achieve this goal. However, the long-term impacts from translocation can be expensive and difficult to evaluate. This dataset is used to evaluate genetic change as a result of translocation and represents sa - Multimedia
- Publications
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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 aiSpatial 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 respDefining 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 sPotential 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 develoDefining 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 (mulPrairie 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 noTargeting 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 distScale-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 statistiBalancing 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 modelBridging 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 funcCompendium to invasive annual grass spatial products for the western United States, January 2010-February 2021
Invasive annual grasses (IAGs) degrade native plant communities, alter fire cycles, impact ecosystem processes, and threaten the persistence of some species. Therefore, controlling the spread of IAGs has become a land management priority in the western United States. A wide array of geospatial data has been developed in the last decade to help land managers combat the invasion and expansion of nonA user guide to selecting invasive annual grass spatial products for the western United States
Invasive annual grasses (IAGs)—including Bromus tectorum (cheatgrass), Taeniatherum caput-medusae (medusahead), and Ventenata dubia (ventenata) species—present significant challenges for rangeland management by altering plant communities, impacting ecosystem function, reducing forage for wildlife and livestock, and increasing fire risk. Numerous spatial data products are used to map IAGs, and unde - Software
popcluster: hierarchical population monitoring frameworks, Version 2.0.0
We developed a method to construct hierarchically nested and biologically relevant groupings of similar habitats associated with field surveys while considering structure/connectedness (movements between habitats). This approach can support mobile species using high fidelity sites where monitoring during surveys occurs, such as birthing grounds, breeding grounds, or stopovers/seasonal habitats forSpatial scale selection for greater sage-grouse population trends, Version 1.0.0
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 (Artemisia spp.) cover from a remote sensing product (Rigge et al., 2021; Monroe et al.,grsg_lekdb: Compiling and standardizing greater sage-grouse lek databases, version 1.1.0
Greater sage-grouse (Centrocercus urophasianus) are landscape-scale sagebrush obligate species and an important gamebird and iconic species of the western United States. They occupy the sagebrush biome in western North America, extending east of the Sierra Nevada/Cascade Mountain ranges to the western regions of the Great Plains of the United States. Sage-grouse are one of the most closely monitorlcp_centrality: Defining least-cost paths and graph theory centrality measures
We present software that creates least-cost path spanning trees, a least-cost path minimum spanning tree, and graph theory centrality measures. The software was developed to support identification of population structures--specifically, greater sage-grouse (Centrocercus urophasianus), but also support other species or graph theory applications where least-cost paths are desired. We used habitat pagrsg_lekdb: Compiling and standardizing greater sage-grouse lek databases
Greater sage-grouse (Centrocercus urophasianus) are landscape-scale sagebrush obligate species and an important gamebird and iconic species of the western United States. They occupy the sagebrush biome in western North America, extending east of the Sierra Nevada/Cascade Mountain ranges to the western regions of the Great Plains of the United States. Sage-grouse are one of the most closely monitorpopcluster: Developing Hierarchical Population Monitoring Frameworks for mobile species with high site fidelity
The software "popcluster" constructs hierarchically nested groupings of similar habitats associated with field surveys while considering biological structure/connectedness (movements between habitats). This approach can support mobile species with high site fidelity where monitoring during surveys occurs on birthing grounds, breeding grounds, or stopovers/seasonal habitat for migratory s - News