Southwest Biological Science Center

Aquatic Ecosystems

Filter Total Items: 36
Date published: December 13, 2016

Using Imagery to Monitor Riparian and Upland Vegetation Along the San Pedro River, Arizona

The Upper San Pedro River is one of the few remaining undammed rivers that maintain a vibrant riparian ecosystem in the southwest. However, its riparian forest is threatened by diminishing groundwater and surface water inputs, due to either changes in watershed characteristics such as changes in riparian and upland vegetation, or human activities such as regional groundwater pumping. We used...

Contacts: Pamela Nagler
Date published: December 12, 2016
Status: Active

Suspended-Sediment Transport Dynamics of the Rio Grande/Rio Bravo

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 caused by the construction and operation of dams and irrigation diversions in upstream reaches of the Rio Grande in the U.S. and the Rio Conchos in Mexico that has reduced mean and peak...

Date published: December 9, 2016
Status: Active

Modeling Colonization of a Population of Chiricahua Leopard Frogs

Managing a species with intensive tools like reintroduction may focus on single sites or entire landscapes.  For mobile species like the federally-threatened Chiricahua leopard frog (Lithobates chiricahuensis [CLF]), both suitable colonization sites and suitable dispersal corridors between sites are needed. Following the eradication of the invasive American bullfrog (Lithobates catesbeianus)...

Date published: December 9, 2016
Status: Active

Insect Drift

All aquatic invertebrates drift downstream at some point in their life cycle. Invertebrates may drift to find more preferable habitats, to leave the water during their transition from aquatic larvae to terrestrial adults, or accidentally such as when swept off the river bed by a flood. Regardless, when they enter the drift, invertebrates become particularly susceptible to predation by several...

Date published: December 8, 2016
Status: Active

Turtle Ecology

Turtles are among the most recognizable and iconic of animals. Any animal with a shell and a backbone is a turtle whether they are called turtles, tortoises, or terrapins. In fact, terrapin is an Algonquian Native American name for turtle. Worldwide there are 356 turtle species on all continents except for Antarctica. The United States has more species than any other country with about 62 ...

Date published: December 8, 2016
Status: Active

Grand Canyon Sandbar Monitoring

Since the completion of Glen Canyon Dam in 1963, the amount of sand supplied to Grand Canyon National Park has been reduced by more than 90 percent. The Paria River, a tributary to the Colorado River 15 miles downstream from the dam, is now the single most important supplier of sand to the Colorado River within the Park. This large reduction in sand supply has resulted in substantial decrease...

Contacts: Paul Grams, Ph.D., Robert Tusso, Keith A Kohl, Joseph E. Hazel, Jr., Daniel Buscombe, Matt Kaplinski
Date published: December 8, 2016
Status: Active

Adaptive Management

In 1996, the Secretary of the Interior signed a formal decision altering the historical flows from Glen Canyon Dam and establishing the Glen Canyon Dam Adaptive Management Program (GCDAMP). In the context of the management of Glen Canyon Dam, adaptive management was selected to create a process whereby “the effects of dam operations on downstream resources would be assessed and the results of...

Date published: December 7, 2016
Status: Active

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...

Date published: December 5, 2016
Status: Active

Amphibian Chytrid Fungus Sampling in Arizona and Mexico

Information on disease presence can be of use to natural resource managers, especially in areas supporting threatened and endangered species that occur coincidentally with species that are suspected vectors for disease. A general sense of pathogen presence (or absence) can inform management directed at threatened and endangered species, especially in regions where disease is suspected to have...

Date published: December 5, 2016
Status: Active

Sediment Storage in the Colorado River

The sandbars exposed along the shoreline of the Colorado River represent only a small fraction of the sand deposits in Grand Canyon, most of which are on the bed of the river in eddies and the channel. Current management practice includes efforts to maintain and build sandbars by releasing high flows from Glen Canyon Dam that are timed to coincide with periods of fine-sediment supply from...

Date published: December 5, 2016
Status: Active

Aquatic Insects

Aquatic insects live in the water as larvae most of their lives, then emerge onto land for a brief period as winged adults. Sampling these emerged adults on land is therefore a useful tool for understanding the condition of the aquatic insect population that is in the water, particularly in large rivers where sampling the larvae on the river bed is impractical. Our group uses a variety of...

Date published: November 1, 2016
Status: Active

SBSC Updates - Catch Up on Our Activities

SBSC monthly updates highlight new published papers and reports, new research projects, media attention on SBSC science, outreach activities, data, and more. Click on the images to download PDFs of the updates. If you would like the montly updates e-mailed to you each month, please contact Todd Wojtowicz (twojtowicz@usgs.gov).