Stop Spread of Noxious Weeds, Sheldon National Wildlife Refuge, Northern Nevada : 無料・フリー素材/写真
Stop Spread of Noxious Weeds, Sheldon National Wildlife Refuge, Northern Nevada / Ken Lund
| ライセンス | クリエイティブ・コモンズ 表示-継承 2.1 |
|---|---|
| 説明 | The Sheldon National Wildlife Refuge is a 57,304-acre (23,190 ha) national wildlife refuge located on the northern border of the U.S. state of Nevada. A very small part extends northward into Oregon. It is managed by the United States Fish and Wildlife Service as the Nevada component of the Sheldon-Hart Mountain National Wildlife Refuge Complex, which is headquartered in Lakeview, Oregon. The Sheldon Refuge is noted for its population of wild horses. In 1931, the refuge was established under executive order to carry out three central goals: First, the refuge was to provide a habitat for the "antelope" (more properly called the pronghorn), an animal whose population was in decline during the early 1900s. Second, conservation efforts were put forth to protect native fish, wildlife and plants. Finally, the refuge was to serve as an inviolate migratory bird sanctuary. Advocates characterize Sheldon as one of the few intact sagebrush steppe ecosystems in the Great Basin, one that hosts a variety of wildlife endemic to the unique environment. Desert fishes, greater sage-grouse, migratory birds, mule deer and the pygmy rabbit are all residents of the refuge.The Sheldon National Wildlife Refuge occupies an arid zone of volcanic terrain. Rockhounds search for semiprecious stones such as fire opals. Geothermal hot springs provide some water. The dominant ecosystem plant life consists of drought-tolerant species such as sagebrush, juniper, mountain mahogany, bitterbrush, and aspen. The elevation ranges from 4,100 feet (1,200 m) to 7,200 feet (2,200 m) above sea level. In this forbidding landscape lives a large population of free-range fauna, with the American mustang, the so-called "wild horse" of the American West, being the best known. There are also large herds of mule deer, an estimated 3,500 pronghorn, and a small but self-sustaining population of bighorn sheep. The bighorn are not strictly native to the Sheldon Refuge, having been extirpated there during the frontier era and successfully reintroduced about 1930. The pronghorn "antelope" played a key role in the history of the Refuge, as approximately 94 percent of the current protected land area was originally set aside as the Charles Sheldon Antelope Range in 1936. The Refuge is the home of an endemic fish species of limited geographic distribution, the Alvord chub. The nearest community of any size is Denio, Nevada, 14 miles from the Refuge's eastern boundary. The nearest divided highway is Interstate 80 in Winnemucca, Nevada, approximately 100 miles to the south.en.wikipedia.org/wiki/Sheldon_National_Wildlife_Refugeen.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_... |
| 撮影日 | 2015-10-10 13:15:42 |
| 撮影者 | Ken Lund , Reno, Nevada, USA |
| 撮影地 | Nevada, United States 地図 |
| カメラ | Canon PowerShot SX280 HS , Canon |
| 露出 | 0.001 sec (1/1000) |
| 開放F値 | f/5.0 |
| 焦点距離 | 16393.44262 dpi |