Overview of Riparian Vegetation in Grand Canyon Active
Stretch of the Colorado River in 1923 (E.C. La Rue) and in 2017 (H.C. Fairley & A.H. Fairley)
Riparian areas are conspicuous belts of dense, green vegetation along streams and rivers, and can be considered “ribbons of life”. Despite covering less than 2 percent of the land area in the southwestern U.S., riparian areas tend to have high species diversity and population density, making them valuable to managers, scientists, and the public. These unique ecosystems act as a link between dry, terrestrial uplands and aquatic ecosystems. Wildlife depend on riparian areas for foraging, nesting, and cover throughout their lives. Riparian vegetation can impact native and non-native fish populations by providing food and cover and influencing water temperature by shading. Also, more than 50 percent of 166 breeding bird species in the lowlands of the southwest are completely dependent on these habitats. Knowing the status of riparian vegetation along the Colorado River and how Glen Canyon Dam operations influences that vegetation is important because changes in riparian plant communities impact wildlife, the transport and deposition of sediment, the stability of sandbars, recreational camping and wilderness experiences, and provides metrics that inform management goals.
Background and Importance: How Glen Canyon Dam has Impacted Riparian Vegetation Communities
Riparian plant research in Grand Canyon began in the early 1900s in the form of plant inventories and collections. Plant collections and research since then have varied in duration and intent, and USGS Grand Canyon Monitoring and Research Center scientists and their cooperators currently document the amount and types of vegetation found along the river corridor and how they may respond to changes in dam operations. In addition to long-term field-based monitoring, GCMRC uses remote sensing of very high resolution multispectral imagery and lidar acquired from fixed-wind airplanes and helicopters to monitor and research the short- and long-term dynamics of riparian vegetation. The long-term goal for monitoring riparian vegetation in the Colorado River is to use annual data on plant cover, species richness, and diversity in concert with semi-decadal vegetation mapping data to distinguish between the effects of dam operations and other environmental- or human-caused changes on riparian vegetation. Trend detection at the reach or regional scale will provide information about gains or losses in vegetated area and about the vegetation classes that change the most.
Prior to the establishment of the Glen Canyon Dam in 1963, the Colorado River through the Grand Canyon would seasonally flood with annual high flows of 85,000 cubic feet per second (f3/s) to the highest ever recorded of 210,000 cubic feet per second (f3/s). These flood events, typically from springtime snowmelt in the Rocky Mountains, would presumably scour the Colorado River corridor of plants, leaving sandy beaches and sparse patches of greenery. Without the scouring floods that came through the river before the Glen Canyon Dam, vegetation abundance has increased and is continually changing in response to varying flow regimes.
The floristic communities downstream along the Colorado River corridor have and continue to change in response to the Glen Canyon Dam’s regulated flow regimes that began in 1963. Operating criteria associated with the Environmental Impact Statement for Glen Canyon Dam completed in 1996 resulted in daily flows that fluctuate by 8,000 f3/s in a day and up to 25,000 f3/s in volume. These dam operations create distinct belts of vegetation that are botanically diverse.
As illustrated in the diagram above, the area of riverbank where plants might be inundated on a daily basis is the active channel (flows up to 25,000 f3/s). High steady releases, also associated with High Flow Experiments (HFEs) implemented since 1996 (1996, 2004, 2008, 2012, 2013, 2016, 2017) have created an active floodplain that extends to elevations where discharges of 45,000 f3/s reach. Plants in the active floodplain have less frequent access to water. Finally, without massive high flows from spring runoff, there is an inactive floodplain - a relic of a time before the dam when plants would receive once or twice yearly inundation above 45,000 f3/s. These three hydrologic zones created by the Glen Canyon Dam have distinct botanical differences. With the changes to riparian hydrologic zones brought about by the Glen Canyon Dam, riparian plant composition has subsequently changed throughout time.
Below are other science projects associated with this project.
Below are data releases associated with this project.
Below are publications associated with this project.
Case studies of riparian and watershed restoration in the southwestern United States—Principles, challenges, and successes
Variation in species-level plant functional traits over wetland indicator status categories
Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon
Functional traits and ecological affinities of riparian plants along the Colorado River in Grand Canyon
Four-band image mosaic of the Colorado River corridor downstream of Glen Canyon Dam in Arizona, derived from the May 2013 airborne image acquisition
Remote sensing of tamarisk biomass, insect herbivory, and defoliation: Novel methods in the Grand Canyon Region, Arizona
Riparian vegetation, Colorado River, and climate: five decades of spatiotemporal dynamics in the Grand Canyon with river regulation
Riparian vegetation response to the March 2008 short-duration, High-Flow Experiment— Implications of timing and frequency of flood disturbance on nonnative plant establishment along the Colorado River below Glen Canyon Dam
A Vegetation Database for the Colorado River Ecosystem from Glen Canyon Dam to the Western Boundary of Grand Canyon National Park, Arizona
Do beavers promote the invasion of non-native Tamarix in the Grand Canyon riparian zone
Below are partners associated with this project.
- Overview
Riparian areas are conspicuous belts of dense, green vegetation along streams and rivers, and can be considered “ribbons of life”. Despite covering less than 2 percent of the land area in the southwestern U.S., riparian areas tend to have high species diversity and population density, making them valuable to managers, scientists, and the public. These unique ecosystems act as a link between dry, terrestrial uplands and aquatic ecosystems. Wildlife depend on riparian areas for foraging, nesting, and cover throughout their lives. Riparian vegetation can impact native and non-native fish populations by providing food and cover and influencing water temperature by shading. Also, more than 50 percent of 166 breeding bird species in the lowlands of the southwest are completely dependent on these habitats. Knowing the status of riparian vegetation along the Colorado River and how Glen Canyon Dam operations influences that vegetation is important because changes in riparian plant communities impact wildlife, the transport and deposition of sediment, the stability of sandbars, recreational camping and wilderness experiences, and provides metrics that inform management goals.
Background and Importance: How Glen Canyon Dam has Impacted Riparian Vegetation Communities
Riparian plant research in Grand Canyon began in the early 1900s in the form of plant inventories and collections. Plant collections and research since then have varied in duration and intent, and USGS Grand Canyon Monitoring and Research Center scientists and their cooperators currently document the amount and types of vegetation found along the river corridor and how they may respond to changes in dam operations. In addition to long-term field-based monitoring, GCMRC uses remote sensing of very high resolution multispectral imagery and lidar acquired from fixed-wind airplanes and helicopters to monitor and research the short- and long-term dynamics of riparian vegetation. The long-term goal for monitoring riparian vegetation in the Colorado River is to use annual data on plant cover, species richness, and diversity in concert with semi-decadal vegetation mapping data to distinguish between the effects of dam operations and other environmental- or human-caused changes on riparian vegetation. Trend detection at the reach or regional scale will provide information about gains or losses in vegetated area and about the vegetation classes that change the most.
Prior to the establishment of the Glen Canyon Dam in 1963, the Colorado River through the Grand Canyon would seasonally flood with annual high flows of 85,000 cubic feet per second (f3/s) to the highest ever recorded of 210,000 cubic feet per second (f3/s). These flood events, typically from springtime snowmelt in the Rocky Mountains, would presumably scour the Colorado River corridor of plants, leaving sandy beaches and sparse patches of greenery. Without the scouring floods that came through the river before the Glen Canyon Dam, vegetation abundance has increased and is continually changing in response to varying flow regimes.
The floristic communities downstream along the Colorado River corridor have and continue to change in response to the Glen Canyon Dam’s regulated flow regimes that began in 1963. Operating criteria associated with the Environmental Impact Statement for Glen Canyon Dam completed in 1996 resulted in daily flows that fluctuate by 8,000 f3/s in a day and up to 25,000 f3/s in volume. These dam operations create distinct belts of vegetation that are botanically diverse.
Sources/Usage: Public Domain. View Media DetailsAs illustrated in the diagram above, the area of riverbank where plants might be inundated on a daily basis is the active channel (flows up to 25,000 f3/s). High steady releases, also associated with High Flow Experiments (HFEs) implemented since 1996 (1996, 2004, 2008, 2012, 2013, 2016, 2017) have created an active floodplain that extends to elevations where discharges of 45,000 f3/s reach. Plants in the active floodplain have less frequent access to water. Finally, without massive high flows from spring runoff, there is an inactive floodplain - a relic of a time before the dam when plants would receive once or twice yearly inundation above 45,000 f3/s. These three hydrologic zones created by the Glen Canyon Dam have distinct botanical differences. With the changes to riparian hydrologic zones brought about by the Glen Canyon Dam, riparian plant composition has subsequently changed throughout time.
- Science
Below are other science projects associated with this project.
- Data
Below are data releases associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 22Case studies of riparian and watershed restoration in the southwestern United States—Principles, challenges, and successes
Globally, rivers and streams are highly altered by impoundments, diversions, and stream channelization associated with agricultural and water delivery needs. Climate change imposes additional challenges by further reducing discharge, introducing variability in seasonal precipitation patterns, and increasing temperatures. Collectively, these changes in a river or stream’s annual hydrology affects sAuthorsBarbara E. Ralston, Daniel A. SarrVariation in species-level plant functional traits over wetland indicator status categories
Wetland indicator status (WIS) describes the habitat affinity of plant species and is used in wetland delineations and resource inventories. Understanding how species-level functional traits vary across WIS categories may improve designations, elucidate mechanisms of adaptation, and explain habitat optima and niche. We investigated differences in species-level traits of riparian flora across WIS cAuthorsMiles E. McCoy-Sulentic, Thomas E. Kolb, David M. Merritt, Emily C. Palmquist, Barbara E. Ralston, Daniel A. SarrChanges in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon
Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over hyAuthorsMiles McCoy-Sulentic, Thomas Kolb, David Merritt, Emily C. Palmquist, Barbara E. Ralston, Daniel Sarr, Patrick B. ShafrothFunctional traits and ecological affinities of riparian plants along the Colorado River in Grand Canyon
Trait-based approaches to vegetation analyses are becoming more prevalent in studies of riparian vegetation dynamics, including responses to flow regulation, groundwater pumping, and climate change. These analyses require species trait data compiled from the literature and floras or original field measurements. Gathering such data makes trait-based research time intensive at best and impracticableAuthorsEmily C. Palmquist, Barbara E. Ralston, Sarr. Daniel, David Merritt, Patrick B Shafroth, Julian ScottFour-band image mosaic of the Colorado River corridor downstream of Glen Canyon Dam in Arizona, derived from the May 2013 airborne image acquisition
In May 2013, the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center acquired airborne multispectral high-resolution data for the Colorado River in the Grand Canyon, Arizona. The image data, which consist of four color bands (blue, green, red, and near-infrared) with a ground resolution of 20 centimeters, are available to the public as 16-bit geotiff files at http://dx.doi.org/10.AuthorsLaura E. Durning, Joel B. Sankey, Philip A. Davis, Temuulen T. SankeyRemote sensing of tamarisk biomass, insect herbivory, and defoliation: Novel methods in the Grand Canyon Region, Arizona
Tamarisk is an invasive, riparian shrub species in the southwestern USA. The northern tamarisk beetle (Diorhabda carinulata) has been introduced to several states to control tamarisk. We classified tamarisk distribution in the Glen Canyon National Recreation Area, Arizona using a 0.2 m resolution, airborne multispectral data and estimated tamarisk beetle effects (overall accuracy of 86 percent) leAuthorsTemuulen T. Sankey, Joel B. Sankey, Rene Horne, Ashton BedfordRiparian vegetation, Colorado River, and climate: five decades of spatiotemporal dynamics in the Grand Canyon with river regulation
Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen CanyonAuthorsJoel B. Sankey, Barbara E. Ralston, Paul E. Grams, John C. Schmidt, Laura E. CagneyRiparian vegetation response to the March 2008 short-duration, High-Flow Experiment— Implications of timing and frequency of flood disturbance on nonnative plant establishment along the Colorado River below Glen Canyon Dam
Riparian plant communities exhibit various levels of diversity and richness. These communities are affected by flooding and are vulnerable to colonization by nonnative species. Since 1996, a series of three high-flow experiments (HFE), or water releases designed to mimic natural seasonal flooding, have been conducted at Glen Canyon Dam, Ariz., primarily to determine the effectiveness of using highAuthorsBarbara E. RalstonA Vegetation Database for the Colorado River Ecosystem from Glen Canyon Dam to the Western Boundary of Grand Canyon National Park, Arizona
A vegetation database of the riparian vegetation located within the Colorado River ecosystem (CRE), a subsection of the Colorado River between Glen Canyon Dam and the western boundary of Grand Canyon National Park, was constructed using four-band image mosaics acquired in May 2002. A digital line scanner was flown over the Colorado River corridor in Arizona by ISTAR Americas, using a Leica ADS-40AuthorsBarbara E. Ralston, Philip A. Davis, Robert M. Weber, Jill M. RundallDo beavers promote the invasion of non-native Tamarix in the Grand Canyon riparian zone
Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding's willow) and Salix exigua Nutt. (coyote willow) are a staple food of beavers. Because Salix competes with the invasivAuthorsS.G. Mortenson, P.J. Weisberg, B.E. Ralston - Partners
Below are partners associated with this project.