Jackson Hill, at an elevation of feet is its highest point. From to , the government leased San Nicolas Island to private sheep-ranching interests. There are over different plant species which grow on San Nicolas Island, four of which are restricted to San Nicolas: an un-described species of Malacothrix, a member of the sunflower family; a phacelia Phacelia cinerea ; a buckwheat Erigonum grande timorum ; and a box thorn Lycium verrucosum.
The phacelia and the box thorn may now be extinct. There are two native terrestrial mammals found on San Nicolas Island: the endemic subspecies of island fox Urocyon littoralis dickeyi ; and an endemic species of the deer mouse Peromyscus maniculatus exterus. San Nicolas Island is relatively flat-topped with a mesa-like profile. The western end contains large shifting sand dunes, while the eastern end is very precipitous with a large sand spit extending eastward.
The southern or leeward side of the island is a giant excarpment which rises from the sea to feet within a mile of shore. The northern side of the island has cliffs which rise as wave-cut terraces to the mesa at feet above sea level. S ix of the eight islands in the Channel Islands Archipelago are home to a fox subspecies found nowhere else in the world. San Nicolas Island supports a large and healthy population of this island fox. Natural vegetation, once common throughout California, is now restricted to the most remote or protected corners of the state, such as San Nicolas.
Howling winds, extremes of temperature, and torrential storms have created a tough environment, and native life has adapted to these rugged conditions—but not to the presence of non-native, invasive feral cats.
For years, feral cats competed with foxes for food and resources, and directly preyed on seabirds and lizards. In , Island Conservation and our partners relocated feral cats from San Nicolas to a permanent sanctuary on mainland California. Since the island was declared free of feral cats, native plants and animals have recovered and species are thriving. San Nicolas Island is a relatively untouched ecosystem, home to numerous species found exclusively in the Channel Islands, including at least twenty-five invertebrates, sixteen plant species, one reptile, three birds, and two mammals.
San Nicolas supports three rare native vegetation communities and important seabird colonies and is surrounded by a spectacular marine and intertidal environment teeming with Harbor Seals, California Sea Lions, Southern Sea Otters, and Northern Elephant Seals. Island Conservation and our partners employed cutting-edge technology that helped make the project a success. Field staff utilized rugged pocket computers loaded with GPS and GIS capabilities to record data and locations and to track our coverage of the island.
Only eight miles long and about three and a half miles across at its widest point, it is the farthest from the mainland, more than 60 miles offshore. Via charter dive boat, it is reached only after a seven-to eight-hour ride.
San Nic has been owned by the U. Government and under the jurisdiction of the U. Navy since It contains a large Navy base, which includes tennis courts, a racquet ball court, a movie theater, a bowling alley, a recreation center and a 10, foot runway.
The island is off limits to civilians.
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