Researchers, including Jonathan Friedman (pictured here) planted cottonwoods in this Common Garden plot in 2005, and since have monitored the growth and phenology of these trees. Every year since 2017, they cut back the trees to remove the confounding effect of age.
Janet Prevéy, PhD
Janet Prevéy is a Biologist at the Fort Collins Science Center, whose research focuses on how environmental changes affect vegetation dynamics and phenology across different spatial and temporal scales.
Janet Prevéy's research examines how disturbances such as wildfire interact with invasive species to influence ecosystem structure and function. She conducts large-scale data syntheses and develops predictive models to help land managers identify the optimal timing for invasive species control and prioritize limited resources for areas at greatest risk of invasion. Her research ultimately aims to develop spatial decision-support tools that protect native ecosystems from invasive species while helping streamline land management decisions.
Science and Products
Scaling-up phenological date matching for invasive species mapping: a free opensource workflow
Matching imagery dates to phenological events across large geographic regions for invasive species mapping.
FORT Cottonwood Common Garden
FORT scientists established a Common Garden at the Colorado State Forest Service Nursery in Fort Collins, Colorado in 2005 to study the phenology of riparian cottonwood in relation to annual variation in temperature. Phenology is the seasonal timing of life history events including leaf opening, flowering, seed release, bud formation and leaf senescence.
INHABIT: A web tool for invasive plant management across the contiguous United States
INHABIT is a desktop-optimized web application and decision support tool with mapped and tabular summaries of habitat suitability models for over two hundred fifty terrestrial invasive plant species of management concern across the contiguous United States. It is the product of a scientist-practitioner partnership and is designed to facilitate enhanced invasive species management actions...
Predicting risk of annual grass invasion following fire in sagebrush steppe and rangeland ecosystems
This project analyzes on-the-ground plant monitoring data across sagebrush and rangeland ecosystems to examine how fire, climate, topography, and plant communities influence the success of invasive annual grasses after fires.
Predicting the phenology of invasive grasses under a changing climate to inform mapping and management
Cheatgrass, an invasive annual grass, reduces ecosystem productivity, negatively impacts biodiversity, and is increasingly problematic in higher elevation ecosystems with climate change. Cheatgrass phenology (that is, the timing of yearly growth and lifespan) varies greatly with elevation, climate, and weather from year to year, which can make management planning difficult and reduce the ability...
Climate Impacts on the Locations and Availability of Traditional Food Sources from Native Northwestern Shrubs
Fruit-producing shrubs such as huckleberries, salal, and hazelnut are an important component of social history and traditional tribal diets in the Pacific Northwest. The fruits of these shrubs are also an important food source for foraging wildlife and pollinators, and serve as the basis for both non-tribal harvesting and small-scale commercial operations. Among land managers and tribes...
The Cottonwood Common Garden in 2025
Researchers, including Jonathan Friedman (pictured here) planted cottonwoods in this Common Garden plot in 2005, and since have monitored the growth and phenology of these trees. Every year since 2017, they cut back the trees to remove the confounding effect of age.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.In 2022, researchers set up a timelapse camera to take daily photographs of cheatgrass growth in Wyoming. In this slideshow, photos from every few weeks show how much faster cheatgrass completes its annual life cycle, compared to its native counterparts.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.In 2022, researchers set up a timelapse camera to take daily photographs of cheatgrass growth in Wyoming. In this slideshow, photos from every few weeks show how much faster cheatgrass completes its annual life cycle, compared to its native counterparts.
Cheatgrass
Photograph of cheatgrass by Fort Collins Science Center biologist Janet Prevéy (USGS).
Photograph of cheatgrass by Fort Collins Science Center biologist Janet Prevéy (USGS).
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenology
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenologyWe are deploying timelapse cameras across elevational and latitudinal gradients to capture variation in cheatgrass phenology.
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenology
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenologyWe are deploying timelapse cameras across elevational and latitudinal gradients to capture variation in cheatgrass phenology.
Timelapse camera imagery of cheatgrass growing over time
Timelapse camera imagery of cheatgrass growing over timeTimelapse camera imagery of cheatgrass growing over time after the Mullen fire in southern Wyoming. These images provide precise dates of green-up, flowering, and senescence of cheatgrass which can be paired with local climate data to create phenological predictions.
Timelapse camera imagery of cheatgrass growing over time
Timelapse camera imagery of cheatgrass growing over timeTimelapse camera imagery of cheatgrass growing over time after the Mullen fire in southern Wyoming. These images provide precise dates of green-up, flowering, and senescence of cheatgrass which can be paired with local climate data to create phenological predictions.
Landscape after a fire
Burned area following the Mullen fire in 2020 in southern Wyoming. Invasive annual grasses may be becoming more abundant at higher elevations after disturbances like fire, and tools are needed to accurately map potential invasions across topographic gradients. Photo by Janet Prevéy (USGS).
Burned area following the Mullen fire in 2020 in southern Wyoming. Invasive annual grasses may be becoming more abundant at higher elevations after disturbances like fire, and tools are needed to accurately map potential invasions across topographic gradients. Photo by Janet Prevéy (USGS).
Science and Products
Scaling-up phenological date matching for invasive species mapping: a free opensource workflow
Matching imagery dates to phenological events across large geographic regions for invasive species mapping.
FORT Cottonwood Common Garden
FORT scientists established a Common Garden at the Colorado State Forest Service Nursery in Fort Collins, Colorado in 2005 to study the phenology of riparian cottonwood in relation to annual variation in temperature. Phenology is the seasonal timing of life history events including leaf opening, flowering, seed release, bud formation and leaf senescence.
INHABIT: A web tool for invasive plant management across the contiguous United States
INHABIT is a desktop-optimized web application and decision support tool with mapped and tabular summaries of habitat suitability models for over two hundred fifty terrestrial invasive plant species of management concern across the contiguous United States. It is the product of a scientist-practitioner partnership and is designed to facilitate enhanced invasive species management actions...
Predicting risk of annual grass invasion following fire in sagebrush steppe and rangeland ecosystems
This project analyzes on-the-ground plant monitoring data across sagebrush and rangeland ecosystems to examine how fire, climate, topography, and plant communities influence the success of invasive annual grasses after fires.
Predicting the phenology of invasive grasses under a changing climate to inform mapping and management
Cheatgrass, an invasive annual grass, reduces ecosystem productivity, negatively impacts biodiversity, and is increasingly problematic in higher elevation ecosystems with climate change. Cheatgrass phenology (that is, the timing of yearly growth and lifespan) varies greatly with elevation, climate, and weather from year to year, which can make management planning difficult and reduce the ability...
Climate Impacts on the Locations and Availability of Traditional Food Sources from Native Northwestern Shrubs
Fruit-producing shrubs such as huckleberries, salal, and hazelnut are an important component of social history and traditional tribal diets in the Pacific Northwest. The fruits of these shrubs are also an important food source for foraging wildlife and pollinators, and serve as the basis for both non-tribal harvesting and small-scale commercial operations. Among land managers and tribes...
The Cottonwood Common Garden in 2025
Researchers, including Jonathan Friedman (pictured here) planted cottonwoods in this Common Garden plot in 2005, and since have monitored the growth and phenology of these trees. Every year since 2017, they cut back the trees to remove the confounding effect of age.
Researchers, including Jonathan Friedman (pictured here) planted cottonwoods in this Common Garden plot in 2005, and since have monitored the growth and phenology of these trees. Every year since 2017, they cut back the trees to remove the confounding effect of age.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.In 2022, researchers set up a timelapse camera to take daily photographs of cheatgrass growth in Wyoming. In this slideshow, photos from every few weeks show how much faster cheatgrass completes its annual life cycle, compared to its native counterparts.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.
Timelapse photography of a mixed landscape of cheatgrass and native grasses.In 2022, researchers set up a timelapse camera to take daily photographs of cheatgrass growth in Wyoming. In this slideshow, photos from every few weeks show how much faster cheatgrass completes its annual life cycle, compared to its native counterparts.
Cheatgrass
Photograph of cheatgrass by Fort Collins Science Center biologist Janet Prevéy (USGS).
Photograph of cheatgrass by Fort Collins Science Center biologist Janet Prevéy (USGS).
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenology
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenologyWe are deploying timelapse cameras across elevational and latitudinal gradients to capture variation in cheatgrass phenology.
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenology
USGS researcher Janet Prevey deploys timelapse camera to capture cheatgrass phenologyWe are deploying timelapse cameras across elevational and latitudinal gradients to capture variation in cheatgrass phenology.
Timelapse camera imagery of cheatgrass growing over time
Timelapse camera imagery of cheatgrass growing over timeTimelapse camera imagery of cheatgrass growing over time after the Mullen fire in southern Wyoming. These images provide precise dates of green-up, flowering, and senescence of cheatgrass which can be paired with local climate data to create phenological predictions.
Timelapse camera imagery of cheatgrass growing over time
Timelapse camera imagery of cheatgrass growing over timeTimelapse camera imagery of cheatgrass growing over time after the Mullen fire in southern Wyoming. These images provide precise dates of green-up, flowering, and senescence of cheatgrass which can be paired with local climate data to create phenological predictions.
Landscape after a fire
Burned area following the Mullen fire in 2020 in southern Wyoming. Invasive annual grasses may be becoming more abundant at higher elevations after disturbances like fire, and tools are needed to accurately map potential invasions across topographic gradients. Photo by Janet Prevéy (USGS).
Burned area following the Mullen fire in 2020 in southern Wyoming. Invasive annual grasses may be becoming more abundant at higher elevations after disturbances like fire, and tools are needed to accurately map potential invasions across topographic gradients. Photo by Janet Prevéy (USGS).