Threatened and Endangered Species
Threatened and Endangered Species
Filter Total Items: 22
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 response...
Status of Northern Leopard Frogs in the Southwest
Although it is not listed on the Federal Endangered Species list, there is considerable concern over northern leopard frog declines in western North America. It is listed as a “special concern” species by some state wildlife agencies (e.g., Arizona Game and Fish Department 1996) and declines have been reported in Arizona, Colorado, New Mexico, and other areas across the west. Leopard frogs have...
Monitoring the Rare Island Night Lizard on San Nicolas Island
The Island Night Lizard was removed from the Federal list of "Threatened" species in May 2014. This rare and unique species represents an ancient lineage whose members are now sparsely distributed across parts of the Southwest North America, south through Mexico to the New World Tropics. The Island Night Lizard has a very small world range, occurring only on three of the southern California...
Endangered Cacti in Arizona
Arizona is the home to at least 10 cacti that are listed as endangered, threatened, or under conservation agreement. Land use and management activities that occur on federal, and to some extent state, lands on which the cacti occur require consultation among the U.S. Fish and Wildlife Service (USFWS), the agency managing the land on which the cacti is growing, and the party proposing an activity...
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) from...
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...
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...
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...
Big Sagebrush Ecosystem Response to Climate & Disturbance
Big sagebrush ecosystems are a major component of landscapes in the western U.S. and provide vital habitat to a wide array of wildlife species. However, big sagebrush ecosystems have been dramatically impacted by disturbances in the past several decades. This collaborative research between USGS and the University of Wyoming focuses on understanding how climatic and soil conditions influence big...
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...