Cattle Increase Occurrence of Ravens That Prey on Sage Grouse plus 1 more |
|
|
Cattle Increase Occurrence of Ravens That Prey on Sage Grouse Posted: 02 Mar 2016 06:00 AM PST
Summary: DIXON, Calif. – Ravens are almost fifty percent more likely to inhabit areas in sagebrush landscapes if cattle are present, and preferentially select sites near greater sage-grouse breeding grounds.
Contact Information: Catherine Puckett ( Phone: 352-377-2469 ); DIXON, Calif. – Ravens are almost fifty percent more likely to inhabit areas in sagebrush landscapes if cattle are present, and preferentially select sites near greater sage-grouse breeding grounds. These findings have implications for greater sage-grouse management practices aimed at reducing raven predation on sage-grouse nests, according to research published in Ecosphere. Raven abundance in the sagebrush-steppe of the American West has increased three-fold during the last four decades, mostly as a result of unintended food and water subsidies from human land-use practices. Predation is the primary source of sage-grouse nest failure, and reducing ravens access to food and water subsidies could assist with conservation efforts. While removal of ravens may reduce their local abundance in the short term, removing subsidies that promote ravens will likely be more effective for long-term control of raven predation. U.S. Geological Survey and Idaho State University scientists examined the influence of livestock on common ravens in about 400 square miles of sagebrush-steppe ecosystem in southeastern Idaho. Grazing by livestock in these systems is common practice on many public lands, but potential influences of livestock on ravens are poorly understood. “Common ravens are a known predator of numerous species including the greater sage-grouse,” said lead author and USGS scientist Peter Coates. “This study provides information to help rangeland resource managers develop conservation actions that focus on increasing the reproductive success of greater sage-grouse. For example, limiting raven access to livestock resources, such as water troughs, and adjusting the timing of livestock access to sage-grouse breeding areas during the spring, would likely reduce raven predation on sage-grouse eggs.” Research findings include:
The study was a partnership of the USGS, Idaho State University, and Idaho Department of Fish and Game. The journal article is available here. Additional project information can be found at the USGS Western Ecological Research Center website. About Greater Sage-Grouse and the Great Basin The Great Basin comprises more than 72.7 million hectares (more than 179 million acres) across five states: Nevada, Utah, Idaho, Oregon and California. Wildfire has been identified as a primary disturbance in the Great Basin. Greater sage-grouse occur in parts of 11 U.S. states and 2 Canadian provinces in western North America. Implementation of effective management actions for the benefit of sage-grouse continues to be a focus of Department of the Interior agencies following the decision by the U.S. Fish and Wildlife Service that the species is not warranted for listing under the Endangered Species Act. |
||||||
|
Snake Fungal Disease Found in Louisiana Posted: 01 Mar 2016 05:36 PM PST
Summary: Snake fungal disease, or SFD, a disease causing high mortality rates in some species of snakes, has been found in Louisiana for the first time, according to a new study by U.S. Geological Survey scientists. SFD now has been confirmed in at least 16 states in the Eastern and Midwestern United States.
Disease now confirmed in at least 16 statesContact Information: Brad Glorioso ( Phone: 337-266-8836 ); Gabrielle Bodin ( Phone: 337-266-8655 ); Snake fungal disease, or SFD, a disease causing high mortality rates in some species of snakes, has been found in Louisiana for the first time, according to a new study by U.S. Geological Survey scientists. SFD now has been confirmed in at least 16 states in the Eastern and Midwestern United States. Wild snakes play important roles in ecosystems as both predator and prey. They provide direct benefits to humans such as consuming crop-destroying pests. Snakes are efficient predators upon various rodents, which may damage property, ruin crops and spread disease. In addition, snake venom research has provided several medicines that are used to halt heart attacks and prevent blood clots and continues to show promise in other areas of medicine. “Snakes may not be everyone’s favorite animal, but they are undeniably important in a well-balanced ecosystem,” said USGS Ecologist Brad “Bones” Glorioso, lead author of the study. “They deserve our respect and understanding.” SFD is characterized by scabs or crusty scales, nodules below the skin, cloudy eyes, abnormal molting, and areas of thickened skin. Snakes infected with SFD, besides being lethargic and lacking an appetite, will attempt to bask in the sun to raise their body temperatures despite unsuitable conditions. This behavior, in addition to the fact that infected snakes are often in poor body condition, makes them more vulnerable to predators. “SFD is an emerging threat to wild snake populations particularly in the eastern United States,” Glorioso added. “We don’t know yet how the disease affects various species, but in at least one species, an estimated 80 to 90 percent of infected snakes die from the disease.” In Louisiana, the first confirmed case of the disease was in a juvenile snake from the Cypress Island Preserve near Lafayette. It is one of the few documented cases in the US of the disease in a juvenile snake. “Finding the disease in a juvenile snake is of particular concern. If younger snakes die from the disease before reaching reproductive age, it could have devastating effects on snake populations,” said Glorioso. Since completing the initial study, the researchers have confirmed the presence of the disease in snakes from other locations in the state. In the last two decades, fungal and fungal-like diseases, including chytridiomycosis in amphibians, white-nose syndrome in bats, and colony collapse disorder in bees, have caused some of the most severe die-offs and extinctions ever observed in wild species. USGS scientists recently identified the specific fungus responsible for causing snake fungal disease. The disease was implicated in recent die-offs and declines in populations of two protected species of pit viper in the Midwest and Northeast. In Midwest populations of the massasauga, a candidate for federal listing under the Endangered Species Act, infected snakes have an estimated 80 percent to 90 percent mortality rate. Mortality rates of infected timber rattlesnakes in the Northeast are estimated between 30 percent and 70 percent. To date, the disease has been confirmed in at least 14 snake species including the northern water snake; racer; rat snake; timber rattlesnake; massasauga; pygmy rattlesnake; milk snake; plains garter snake; mud snake and southern water snake. It is believed to be more widespread than is currently documented as snakes showing signs of infection have been reported in other states and in other species. The authors have begun a more detailed capture-mark-recapture study on snakes at Palmetto Island State Park that includes taking swabs of all snakes, including those that appear healthy, to be tested for the presence of the fungus that causes SFD. This protocol will allow them to model survival probability based on whether the snake was positive or negative for the fungus, and to determine population trends. The study, “First Documented Case of Snake Fungal Disease in a Free-ranging Wild Snake in Louisiana,” was published in Southeastern Naturalist.
|
||||||
- Prev by Date: Airborne Sensor Shows Promise for Monitoring Water Quality
- Next by Date: Snake Fungal Disease Found in Louisiana
- Previous by thread: Airborne Sensor Shows Promise for Monitoring Water Quality
- Next by thread: Snake Fungal Disease Found in Louisiana
- Index(es):
 |