Declining bighorn sheep populations may be vulnerable to some of the fatal diseases, including chronic wasting disease (CWD), that are found in their western U.S. habitats, according to a new U.S. Geological Survey study.
USGS National Wildlife Health Center (NWHC) research showed that bighorn sheep are likely susceptible to the deadly neurological diseases scrapie and CWD, which are occurring in or near natural bighorn sheep environments. These fatal diseases are caused by mysterious proteins called prions, and are known to infect domestic sheep (scrapie) and non-domestic deer, elk, and moose (CWD). The USGS study is published in the journal BMC Veterinary Research, and is available online.
"Bighorn sheep are economically and culturally important to the western U.S.," said Dr. Christopher Johnson, USGS scientist and senior author of the report. "Understanding future risks to the health of bighorn sheep is key to proper management of the species."
USGS laboratory tests found evidence that bighorn sheep could be vulnerable to CWD from either white-tailed deer or elk, and to a domestic sheep prion disease known as scrapie. However, none of a small number of bighorn sheep sampled in the study showed evidence of infection.
"Our results do not mean that bighorns get, or will eventually get, prion diseases," Johnson said. "However, wildlife species like bighorn sheep are increasingly exposed to areas where CWD occurs as the disease expands to new geographical areas and increases in prevalence."
The laboratory test results could be useful to wildlife managers because bighorn sheep habitats overlap with farms and ranches with scrapie-infected sheep and regions where CWD is common in deer, elk, and moose.
Bighorn sheep populations in western North America have declined from habitat loss and, more recently, epidemics of fatal pneumonia thought to be transmitted to them from domestic sheep. Prion diseases are another possible threat to this valuable species.
For more information on prion diseases such as CWD, please visit the USGS NWHC website.
Hurricane Sandy Eroded Half of Fire Island's Beaches and Dunes: New Report Quantifies Coastal Change
ST. PETERSBURG, Fla. – Beaches and dunes on Fire Island, New York, lost more than half of their pre-storm volume during Hurricane Sandy, leaving the area more vulnerable to future storms.
While the damage and destruction on Fire Island was immediately evident after the storm, a new U.S. Geological Survey study released today is the first to quantify the actual changes to the coast caused by the storm.
"The beaches and dunes of the island were severely eroded during Sandy," said Cheryl Hapke, a USGS research geologist and lead author of the study. "The island was breached in three locations, and there was widespread damage and destruction of coastal infrastructure, including private residences. The report shows that the beaches and dunes lost 54.4 percent of their pre-storm volume, and the dunes experienced overwash along 46.6 percent of the island, dramatically changing the island’s shape."
Field surveys conducted immediately after Sandy documented low, flat beaches and extensive dune erosion. Assessment of overwash deposits -- the material that was carried to the interior of the island -- indicates that most of the sand lost from the beaches and dunes during Hurricane Sandy was moved offshore, carried by waves and storm surge. Of the volume of sand that was lost from the beaches and dunes, 14 percent was deposited inland.
"The impact from Sandy was unprecedented in recent times," said Hapke. "It is important that efforts to rebuild on the island be guided by the science, which shows that Sandy profoundly altered the shape and position of the barrier island, shifting it landward and redistributing large amounts of sand. Storms like Sandy are part of the natural evolution of barrier islands, which ultimately result in islands that are more resilient to sea level rise."
The extreme erosion of the beach and loss of dunes made the island more vulnerable to subsequent winter storms. In the course of the following winter months, the shoreline position shifted as much as 57.5 meters (189 feet) inland. Although several areas begin to experience some recovery in the early spring, at the end of the survey period only a small fraction, 18 percent, of the pre-Sandy beach volume had returned.
"Barrier islands provide natural protection against storms, shielding coastlines from rising waves and tides," said Hapke. "The loss of so much sand increases the vulnerability of this area of coastline to future storms."
Fire Island is the longest of the barrier islands that lie along the south shore of Long Island, New York. The majority of the island is part of Fire Island National Seashore and not only provides the first line of defense against storms, but is a unique and important recreational and ecosystem resource. USGS research on Fire Island focuses understanding the evolution of the form and structure of the barrier system on a variety of time scales, including storm driven change in the region.
Scientists have detected magmatic water — water that originates from deep within the Moon's interior — on the surface of the Moon. These findings, published in the August 25 issue of Nature Geoscience, represent the first such remote detection of this type of lunar water, and were arrived at using data from NASA's Moon Mineralogy Mapper (M3).
The discovery represents an exciting contribution to the rapidly changing understanding of lunar water, said Rachel Klima, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and lead author of the paper, "Remote detection of magmatic water in Bullialdus Crater on the Moon."
"For many years, researchers believed that the rocks from the Moon were 'bone dry' and that any water detected in the Apollo samples had to be contamination from Earth," said Klima, a member of the NASA Lunar Science Institute's (NLSI) Scientific and Exploration Potential of the Lunar Poles team. "About five years ago, new laboratory techniques used to investigate lunar samples revealed that the interior of the Moon is not as dry as we previously thought. Around the same time, data from orbital spacecraft detected water on the lunar surface, which is thought to be a thin layer formed from solar wind hitting the lunar surface."
"This surficial water unfortunately did not give us any information about the magmatic water that