Origins and antiquity of the island fox (Urocyon littoralis) on California’s Channel Islands
Torben C. Rick, Jon M. Erlandson, René L. Vellanoweth, Todd J. Braje, Paul W. Collins, Daniel A. Guthrie, and Thomas W. Stafford Jr. 2009. Origins and antiquity of the island fox (Urocyon littoralis) on California’s Channel Islands. Quaternary Research 71 (2009) 93–98.
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Abstract
The island fox (Urocyon littoralis) is one of few reportedly endemic terrestrial mammals on California’s Channel Islands. Questions remain about how and when foxes first colonized the islands, with researchers speculating on a natural, human-assisted, or combined dispersal during the late Pleistocene and/or Holocene. A natural dispersal of foxes to the northern Channel Islands has been supported by reports of a few fox bones from late Pleistocene paleontological localities. Direct AMS 14C dating of these “fossil” fox bones produced dates ranging from ~6400 to 200 cal yr BP, however, postdating human colonization of the islands by several millennia. Although one of these specimens is the earliest securely dated fox from the islands, these new data support the hypothesis that Native Americans introduced foxes to all the Channel Islands in the early to middle Holocene. However, a natural dispersal for the original island colonization cannot be ruled out until further paleontological, archaeological, and genetic studies (especially aDNA [ancient DNA]) are conducted.
Introduction
The endangered island fox (Urocyon littoralis), a diminutive relative of the gray fox (U. cinereoargenteus), has been an important apex predator on California’s Channel Islands for millennia (Collins, 1993; Moore and Collins, 1995; Roemer et al., 2004). While a great deal is known about island fox ecology, biogeography, and conservation, questions remain about when and how these animals first colonized the Channel Islands (Johnson, 1975, 1983;Wenner and Johnson, 1980; Collins, 1991a; Vellanoweth, 1998; Agenbroad, 2002a). Most researchers agree that Native Americans introduced the island fox to the southern Channel Islands, probably during the middle to late Holocene (Collins, 1991a,b; Vellanoweth, 1998; Shelley, 2001). Based partly on reports of fox remains from late Pleistocene sediments of the Upper Tecolote Formation on Santa Rosa Island, however, foxes were thought to have reached the northern Channel Islands naturally during the late Pleistocene by rafting across a Santa Barbara Channel narrowed by lower sea levels (Wenner and Johnson, 1980; Collins, 1991a,b, 1993).
Sea otters, shellfish, and humans: 10,000 years of ecological interaction on San Miguel Island, California
Erlandson, Jon M., Torben C. Rick, Michael Graham, James Estes, Todd Braje, and René Vellanoweth. 2005. Sea otters, shellfish, and humans: 10,000 years of ecological interaction on San Miguel Island, California. Proceedings of the Sixth California Islands Symposium, edited by D.K. Garcelon and C.A. Schwemm, pp. 58-69. Arcata: Institute for Wildlife Studies and National Park Service.
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Abstract
We use data from San Miguel Island shell middens spanning much of the past 10,000 years in a preliminary exploration of long-term ecological relationships between humans, sea otters (Enhydra lutris), shellfish, and kelp forests. At Daisy Cave, human use of marine habitats begins almost 11,500 years ago, with the earliest evidence for shellfish harvesting (11,500 cal BP), intensive kelp bed fishing (ca. 10,000-8500 cal BP), and Sea Otter hunting (ca. 8900 cal BP) from the Pacific Coast of North America. On San Miguel Island, Native Americans appear to have coexisted with sea otters and productive shellfish populations for over 9,000 years, but the emphasis of shellfish harvesting changed over time. Knowledge of modern sea otter behavior and ecology suggests that shell middens dominated by large red abalone shells-relatively common on San Miguel between about 7,300 and 3,300 years ago-are only likely to have formed in areas where sea otter populations had been reduced by Native hunting or other causes. Preliminary analysis of sea urchin lenses, in which the remains of urchins are unusually abundant, may also signal an increasing impact of Island Chumash populations on kelp forest and other near shore habitats during the late Holocene. Such impacts were probably relatively limited, however, when compared to the rapid and severe disruption caused by commercial exploitation under the Spanish, Mexican, and American regimes of historic times.
Introduction
In recent decades, the expansion of sea otter (Enhydra lutris) populations along the central California Coast has devastated once productive abalone and sea urchin fisheries that developed in this predator’s absence, creating tensions between resource managers, fishermen, and environmentalists over the protection and management of sea otter populations. Archaeological data from San Miguel Island suggest, however, that Native Americans, sea otters, and productive shellfish populations coexisted on the northern Channel Islands for thousands of years (Walker 1982). These apparently contradictory data sets raise fundamental questions about the nature of “pristine” prehistoric sea otter and shellfish populations, how Native American harvests were sustained over the millennia, the possible ecological effects of sea otter hunting prior to European contact, and the management of modern sea otter populations and healthy marine ecosystems along the California Coast. …
