For more than a decade, USGS scientists have been leaders in understanding saltcedar invasion on riparian ecosystems in the southwest including effects on plant communities, water loss, erosion, wildlife use and human recreational resources. Models have been developed that quantify the extent of saltcedar distribution and inform management actions. In addition, USGS is studying the effectiveness of biological control to reduce saltcedar populations, and subsequent changes in riparian vegetation.
Saltcedar Research
Ecological Drought in Riparian Ecosystems
Effects of Nonnative Vegetation Management
Ecology and Management of Invasive Riparian Plants
Erosion and Invasive Saltcedar
Riparian Ecology
Biological Invasions of Riparian Ecosystems
Explore our science using the data below.
Northern tamarisk beetle impact and classification maps, Grand Canyon National Park, Arizona
Riparian vegetation, topography, and ground cover constituents along the Upper Colorado River near Moab, UT (2010-2017) (ver. 1.1, Jan 2023)
Riparian vegetation, topography, sediment quality and river corridor geomorphology in the Lower Virgin River 2010-2017
Woody riparian invasive plant presence, stem density, and rank dominance and environmental conditions in 2012 at 238 bridge crossings in the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas, and South Platte River Basins, USA
Remote sensing derived maps of tamarisk (2009) and beetle impacts (2013) along 412 km of the Colorado River in the Grand Canyon, Arizona
Recent publications (2018-2022) related to USGS saltcedar research are listed below. A complete listing of USGS saltcedar publications is available from the button below.
Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon
The transformation of dryland rivers: The future of introduced tamarisk in the U.S.
The transformation of dryland rivers: The future of introduced tamarisk in the U.S.
Monitoring Tamarix changes using WorldView-2 satellite imagery in Grand Canyon National Park, Arizona
Future regulated flows of the Colorado River in Grand Canyon foretell decreased areal extent of sediment and increases in riparian vegetation
Flow‐ecology modelling to inform reservoir releases for riparian restoration and management
Vegetation‐groundwater dynamics at a former uranium mill site following invasion of a biocontrol agent: A time series analysis of Landsat normalized difference vegetation index data
Effect of an environmental flow on vegetation growth and health using ground and remote sensing metrics
Population dynamics of the northern tamarisk beetle (Diorhabda carinulata) in the Colorado River Basin
Population genomic analysis suggests strong influence of river network on spatial distribution of genetic variation in invasive saltcedar across the southwestern United States
Fire and nonnative invasive plants in the central bioregion
- Overview
For more than a decade, USGS scientists have been leaders in understanding saltcedar invasion on riparian ecosystems in the southwest including effects on plant communities, water loss, erosion, wildlife use and human recreational resources. Models have been developed that quantify the extent of saltcedar distribution and inform management actions. In addition, USGS is studying the effectiveness of biological control to reduce saltcedar populations, and subsequent changes in riparian vegetation.
Saltcedar ResearchEcological Drought in Riparian Ecosystems
Drought is killing riparian trees along many rivers in the western United States. The cause can be increasing temperature or decreasing precipitation, flow or water-table elevation. At multiple locations we are relating water availability to physiological measurements of tree survival and water stress, such as ring width, carbon stable isotope ratio and branch hydraulic conductivity. These...Effects of Nonnative Vegetation Management
The Rio Grande/Rio Bravo (hereafter referred to as the Rio Grande) in the Big Bend region of Texas, USA, and Chihuahua, and Coahuila, MX has substantially narrowed since the early 1900s. This narrowing has been exacerbated by the widespread establishment of non-native giant cane (Arundo donax) and tamarisk (Tamarix spp.), both of which help trap sediment and protect banks from natural erosional...Ecology and Management of Invasive Riparian Plants
Due to high rates of disturbance and human activity, streamside or “riparian” areas are prone to colonization and spread of invasive plants. In the western United States, hundreds of thousands of riparian acres are occupied by the invasive shrubs/trees tamarisk and Russian olive, as well as numerous exotic herbaceous plants. Our work focuses on understanding the factors driving the distribution...Erosion and Invasive Saltcedar
Formation of arroyos in the late 1800s greatly increased erosion across the southwestern United States. Since the 1930s, however, this erosion has decreased, partly because of bank stabilization by introduced saltcedar. With Isleta Pueblo Indian Nation, the Aquatic Systems Branch developed a new sediment dating method using saltcedar tree rings. We applied the method in a landmark study of arroyo...Riparian Ecology
Riparian ecologists at the Fort Collins Science Center study interactions among flow, channel change, and vegetation along rivers across the western United States and worldwide. Our work focuses on issues relevant to the management of water and public lands, including dam operation, climate change, invasive species, and ecological restoration. Investigations take place on a range of scales. For...Biological Invasions of Riparian Ecosystems
Beginning in the early twentieth century, non-native trees and shrubs, including tamarisk (also commonly known as saltcedar) and Russian-olive, were introduced to the United States for use as ornamental plants and in erosion-control plantings. These plants spread extensively, becoming the third and fourth most frequently occurring woody riparian plants in the American West. - Data
Explore our science using the data below.
Northern tamarisk beetle impact and classification maps, Grand Canyon National Park, Arizona
These data are satellite image-derived, classification maps of tamarisk (Tamarisk spp.) along the Colorado River in Grand Canyon National Park from river km 315 to 363, approximately from Parashant Canyon to Diamond Creek tributaries. The classification maps are published in TIF raster format. Two maps are published: 1) a classification of healthy, defoliated, and tamarisk canopy dieback from theRiparian vegetation, topography, and ground cover constituents along the Upper Colorado River near Moab, UT (2010-2017) (ver. 1.1, Jan 2023)
The data release presents observations of riparian vegetation, topography, and ground cover in two river reaches of the Upper Colorado River within a river segment extending 208 river kilometers (rkm), from near the Colorado/Utah border to the confluence of the Green River. Methods included field observations and analysis of the plant community five times over eight years in the fall of 2010, 2012Riparian vegetation, topography, sediment quality and river corridor geomorphology in the Lower Virgin River 2010-2017
Plant composition, geomorphic conditions and sediment properties before (2010-2012) and after (2015-2017) the arrival of a biocontrol agent (defoliating beetle in the Diorhabda genus) of invasive Tamarix spp. The data contains four csv files: localization (UTM coordinates of the transects), vegetation and geomorphology, species codes and sediment qualityWoody riparian invasive plant presence, stem density, and rank dominance and environmental conditions in 2012 at 238 bridge crossings in the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas, and South Platte River Basins, USA
This dataset presents observations and measurements of riparian plant invasion, community composition, and environmental conditions at 238 bridge crossings in four western USA river basins: the Colorado Headwaters, upper/middle Rio Grande, upper Arkansas River, and South Platte River (281,946 square kilometers). The 238 sites are a stratified random sample of all bridge crossings in the river basiRemote sensing derived maps of tamarisk (2009) and beetle impacts (2013) along 412 km of the Colorado River in the Grand Canyon, Arizona
These data were compiled for quantifying the area of tamarisks (Tamarix spp.) in May 2009 and to quantify the area of beetle-impacted tamarisk in May 2013 within the 2009 tamarisk classification from Glen Canyon Dam to Separation Canyon, a total distance of 412 km along the Colorado River using the 2009 and 2013 0.2 m high-resolution airborne imagery datasets. We classified tamarisk presence in 20 - Publications
Recent publications (2018-2022) related to USGS saltcedar research are listed below. A complete listing of USGS saltcedar publications is available from the button below.
Hydrologic and geomorphic effects on riparian plant species occurrence and encroachment: Remote sensing of 360 km of the Colorado River in Grand Canyon
A common impact on riparian ecosystem function following river regulation is the expansion and encroachment of riparian plant species in the active river channels and floodplain, which reduces flow of water and suspended sediment between the river, riparian area, and upland ecosystems. We characterized riparian plant species occurrence and quantified encroachment within the dam-regulated ColoradoAuthorsLaura E. Durning, Joel B. Sankey, Charles Yackulic, Paul Grams, Bradley J. Butterfield, Temuulen T. SankeyThe transformation of dryland rivers: The future of introduced tamarisk in the U.S.
Tamarix spp. (tamarisk or saltcedar), a shrub-like tree, was intentionally introduced to the U.S. from Asia in the mid-1800s. Tamarisk thrives in today’s human-altered streamside (riparian) habitats and can be found along wetlands, rivers, lakes, and streams across the western U.S. In 2001, a biological control agent, Diorhabda spp. (tamarisk leaf beetle), was released in six states, and has sinceAuthorsPamela L. Nagler, Julia B. Hull, Charles van Riper, Patrick B. Shafroth, Charles B. YackulicThe transformation of dryland rivers: The future of introduced tamarisk in the U.S.
Tamarix spp. (tamarisk or saltcedar), a shrub-like tree, was intentionally introduced to the U.S. from Asia in the mid-1800s. Tamarisk thrives in today’s human-altered streamside (riparian) habitats and can be found along wetlands, rivers, lakes, and streams across the western U.S. In 2001, a biological control agent, Diorhabda spp. (tamarisk leaf beetle), was released in six states, and has sinceAuthorsPamela L. Nagler, Julia B. Hull, Charles van Riper, Patrick B. Shafroth, Charles B. YackulicMonitoring Tamarix changes using WorldView-2 satellite imagery in Grand Canyon National Park, Arizona
Remote sensing methods are commonly used to monitor the invasive riparian shrub tamarisk (Tamarix spp.) and its response to the northern tamarisk beetle (D. carinulata), a specialized herbivore introduced as a biocontrol agent to control tamarisk in the Southwest USA in 2001. We use a Spectral Angle Mapper (SAM) supervised classification method with WorldView-2 (2 m spatial resolution) multispectrAuthorsNathaniel D. Bransky, Temuulen T. Sankey, Joel B. Sankey, Matthew D. Johnson, Levi R. JamisonFuture regulated flows of the Colorado River in Grand Canyon foretell decreased areal extent of sediment and increases in riparian vegetation
Sediment transfer, or connectivity, by aeolian processes between channel-proximal and upland deposits in river valleys is important for the maintenance of river corridor biophysical characteristics. In regulated river systems, dams control the magnitude and duration of discharge. Alterations to the flow regime driven by dams that increase the inundation duration of sediment, or which drive the encAuthorsAlan Kasprak, Joel B. Sankey, Bradley J. ButterfieldFlow‐ecology modelling to inform reservoir releases for riparian restoration and management
Linked hydrologic, hydraulic, and ecological models can facilitate planning and implementing water releases from reservoirs to achieve ecological objectives along rivers. We applied a flow‐ecology model, the Ecosystem Functions Model (HEC‐EFM), to the Bill Williams River in southwestern USA to estimate areas suitable for recruitment of riparian tree seedlings in the context of managing flow releasAuthorsJohn T Hickey, Patrick B. Shafroth, Woodrow L FieldsVegetation‐groundwater dynamics at a former uranium mill site following invasion of a biocontrol agent: A time series analysis of Landsat normalized difference vegetation index data
Because groundwater recharge in dry regions is generally low, arid and semiarid environments have been considered well‐suited for long‐term isolation of hazardous materials (e.g., radioactive waste). In these dry regions, water lost (transpired) by plants and evaporated from the soil surface, collectively termed evapotranspiration (ET), is usually the primary discharge component in the water balanAuthorsChristopher J. Jarchow, William J. Waugh, Kamel Didan, Armando Barreto-Munoz, Stefanie M. Herrmann, Pamela L. NaglerEffect of an environmental flow on vegetation growth and health using ground and remote sensing metrics
Understanding the effectiveness of environmental flow deliveries along rivers requires monitoring vegetation. Monitoring data are often collected at multiple spatial scales. For riparian vegetation, optical remote sensing methods can estimate growth responses at the riparian corridor scale, and field‐based measures can quantify species composition; however, the extent to which these different measAuthorsMartha M. Gomez-Sapiens, Christopher Jarchow, Karl W. Flessa, Patrick B. Shafroth, Edward P. Glenn, Pamela L. NaglerPopulation dynamics of the northern tamarisk beetle (Diorhabda carinulata) in the Colorado River Basin
Throughout the Southwestern United States, riparian systems contain narrow belts of vegetation along streams and rivers. Although only a small percentage of the total land cover, this ecosystem is important for maintaining high species diversity and population densities of birds. Anthropogenic changes to Western riverine systems have enhanced their susceptibility to invasion by introduced plant spAuthorsLevi R. Jamison, Charles van RiperPopulation genomic analysis suggests strong influence of river network on spatial distribution of genetic variation in invasive saltcedar across the southwestern United States
Understanding the complex influences of landscape and anthropogenic elements that shape the population genetic structure of invasive species provides insight into patterns of colonization and spread. The application of landscape genomics techniques to these questions may offer detailed, previously undocumented insights into factors influencing species invasions. We investigated the spatial patternAuthorsSoo-Rang Lee, Yeong-Seok Jo, Chan-Ho Park, Jonathan M. Friedman, Matthew S. OlsonFire and nonnative invasive plants in the central bioregion
The Central bioregion is a vast area, stretching from Canada to Mexico and from the eastern forests to the Rocky Mountains, dominated by grasslands and shrublands, but inclusive of riparian and other forests. This bioregion has been impacted by many human induced changes, particularly relating to agricultural practices, over the past 150 years. Also changed are fire regimes, first by native peopleAuthorsJames B. Grace, Kristin Zouhar