Nonnative Species

In the Upper Colorado River Basin, smallmouth bass (Micropterus dolomieu) are considered the greatest threat to native fishes and have been linked to declines in federally protected humpback chub (Gila cypha), including one population that was rapidly extirpated in the past. Long-term management efforts have been underway to remove smallmouth bass from rivers in the Upper Basin, but smallmouth...

The federally-listed threatened humpback chub is a native fish of the Colorado River. Despite the environmental changes to the river following the construction of Glen Canyon Dam, humpback chub persists alongside nonnative species, including rainbow trout. The pre-dam Colorado River experienced seasonal variation in temperature and discharge. Seasonal flooding resulted in sediments carried...

The Grand Canyon Monitoring and Research Center currently functions under a Triennial Work Plan (TWP) which is thoroughly reviewed and vetted both internally within the Center and through the GCDAMP Technical Work Group (TWG) and the Adaptive Management Work Group (AMWG). These advisory panels have been a part of the Glen Canyon Dam adaptive management process since the inception of the GCDAMP...

Glen Canyon Dam has altered ecological processes of the Colorado River in Grand Canyon. Before the dam was built, the Colorado River experienced seasonable variable flow rates, including springtime flooding events. These spring floods scoured the river bottom and enhanced natural processes that sustained the Colorado River ecosystem. Since the dam’s construction in 1963, springtime floods have...

Reclamation on lands impacted by energy development is complicated and extremely challenging in arid environments due to unstable soils, exotic species, and low and variable precipitation. The reclamation tactics employed by energy operators vary widely and outcomes can differ across plant communities and soil types. In order to address the knowledge gaps regarding how to successfully and...

Southern Arizona’s semi-desert grasslands provides habitat for flora and fauna, regulates rainfall infiltration and overland flow, mitigates surface erosion and dust production, and sequesters carbon. Sustainable management is important to maintain these ecological services and is of concern for the managers, ranchers, and other people associated with the grassland. The Buenos Aires National...

The Grand Canyon Monitoring and Research Center maintains an enterprise GIS platform built upon ESRI ArcGIS Server and Portal applications. This enterprise system allows for spatial data, maps and analytical tools to be served through online applications. The Geospatial Science and Technology project provides access to this content through different avenues. Online maps can be accessed through...

The goal of Grand Canyon Monitoring and Research Center’s (part of the Southwest Biological Science Center) riparian vegetation monitoring program is to assess changes and trends in plant species composition and cover and relate those changes to Glen Canyon Dam operations, river hydrology, climate, and geomorphology. Monitoring is done by annual field-data collection on plant cover and diversity...

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...

Starting in 2017, U.S. Geological Survey (USGS) researchers and land managers are co-producing a network of restoration field trial sites on Department of Interior (DOI) and surrounding lands in the southwestern U.S. The network systematically tests restoration treatments across a broad range of landscape, soil, and climate conditions. Each site in the network is used to test suitable seed mixes...

Just below Glen Canyon Dam on the Colorado River is a very popular Blue Ribbon trout fishery known for its rainbow trout. However, approximately 78 miles downstream, near were the Little Colorado River flows into the Colorado River, is a population of endangered humpback chub. The introduced rainbow trout can negatively affect native humpback chub by competing with them for food (immature black...

Although most introduced insects are relatively benign, some become high-impact pests causing widespread ecological and economic damage. Introduced insects that are specialists and feed on a single genus of plants can be high-impact as they can potentially eliminate an entire native plant genus over large areas. Luckily, most introduced insects with this feeding behavior do not become high-impact...