Southwest Biological Science Center

Aquatic Ecosystems

Filter Total Items: 29
Date published: May 14, 2017

Rainbow Trout Abundance and Movement in the Colorado River in Grand Canyon

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...

Contacts: Charles Yackulic, Josh Korman
Date published: February 28, 2017
Status: Active

Amazon Dams Network: Advancing Integrative Research and Adaptive Management of Social-Ecological Systems Transformed by Hydroelectric Dams

The overall goal of this project is to advance inter- and trans-disciplinary research coordination, focusing on the transformation of social-ecological systems by hydroelectric dam construction in the Amazon and the United States. The experience gained by Southwest Biological Science Center researchers working on the...

Contacts: Theodore Melis, Simone Athyade, Bette Loiselle, David Kaplan, Stephanie Bohlmann
Date published: February 9, 2017

Invertebrate Drift Downstream of Colorado River Basin Dams

Aquatic invertebrates are critical food for fish and other species that inhabit large rivers. In the Colorado River Basin, invertebrates that get transported down the river (“in the drift”) are particularly important to rainbow trout and other species of interest to recreational users. This research seeks to compare rivers downstream of large dams throughout the Colorado River Basin in order...

Date published: January 18, 2017
Status: Active

Citizen Science Light Trapping in Grand Canyon

Aquatic insects are commonly used to gauge the health of stream and river ecosystems, yet collecting enough samples to adequately characterize a river segment as long as the Colorado River through Grand Canyon (> 250 miles) would be essentially impossible using traditional sampling methods. Since 2012, our group has been collaborating with river guides, private boaters, and educational...

Date published: January 18, 2017

Uncovering the Base of the Food Web: Primary Production Dynamics in the Colorado River

Algae, phytoplankton, and rooted macrophytes represent the base of many aquatic food webs and are known as primary producers. Through photosynthesis, these organisms convert sunlight energy into chemical energy (i.e., carbon) that in turn fuels the growth of animals such as macroinvertebrates and fish. This project uses high frequency measurements of dissolved oxygen, which is a by-product of...

Date published: December 30, 2016
Status: Active

River Sediment Dynamics

Sediment controls the physical habitat of river ecosystems.  Changes in the amount and areal distribution of different sediment types cause changes in river-channel form and river habitat.  The amount and type of sediment suspended in the water column determines water clarity.  Understanding sediment transport and the conditions under which sediment is deposited or eroded from the various...

Date published: December 30, 2016

Southwestern Riparian Zones, Tamarisk Plants, and the Tamarisk Beetle

Introductions of bio-control beetles (genus Diorhabda) are causing defoliation and dieback of exotic Tamarix spp. in riparian zones across the western U.S., yet the factors that determine the plant communities that follow Tamarix decline are poorly understood. In particular, Tamarix-dominated soils are often higher in nutrients, organic matter, and salts than nearby soils, and these soil...

Date published: December 23, 2016

Population Dynamics of Endangered Humpback Chub in Grand Canyon

Construction of Glen Canyon Dam has led to large changes in environmental conditions of the downriver Colorado River. Whereas the pre-dam Colorado River experienced large seasonal variation in temperature and discharge and was highly turbid, the post-dam Colorado River is far less variable in terms of temperature and discharge and is frequently clear. Many nonnative fish species had already...

Date published: December 23, 2016

Understanding Factors Influencing Rainbow Trout Growth in the Colorado River

Rainbow trout is a desirable sport fish that has been introduced in many locations around the world. Although introductions of rainbow trout and other nonnative fishes provide recreational fishing opportunities, they also pose threats to native fish populations. The Glen Canyon Dam Adaptive Management Program has tasked scientists and managers with identifying management options that allow...

Date published: December 22, 2016
Status: Active

SBSC Scientist Directory

Click on "Science" to go to the SBSC scientist directory. When you click on a scientist's name (you may need to scroll down to see all the names), you will be taken to that scientist's professional page and contact information. 

Date published: December 22, 2016

Connectivity of Sand Resources Along the Colorado River in Grand Canyon

We study the links among different geomorphic processes that affect river valley landscapes in the Colorado River downstream from Glen Canyon Dam, Arizona. Dam-released flows affect the deposition and retention of sandbars that serve as sources for other sand resources, such as windblown sand dunes, throughout the Colorado River ecosystem. The degree to which the landscapes are differentially...

Date published: December 21, 2016

Effects of Water Clarity on Survival of Endangered Humpback Chub

Introduced rainbow trout and brown trout are considered a threat to the endangered humpback chub in the Colorado River in Grand Canyon. These introduced species eat native fish, but impacts are difficult to assess because predation vulnerability depends on the physical conditions under which predation takes place. We studied how predation vulnerability of juvenile humpback chub changes in...

Contacts: David Ward