Early Fur-Trapping and the Fate of the Beaver

Adapted from: McNamee, Gregory. 1994. Gila: The Life and Death of an American River. Orion Books, New York.

At the time of European arrival in North America scientists estimate there may have been up to 400 million beaver living on the continent; by 1850 the number stood at only 9 million. Having eliminated the beaver from Europe by 1600, European explorers found in America a rich resource and within 250 years the pattern of extirpation had nearly been repeated. More than any other economic activity, the fur trade opened the West to American expansion. Trappers led the way for many settlers, and their names, including those of Bill Williams, Antoine Leroux, and Kit Carson, are engraved in the region's history

Line drawing courtesy of the US Fish and Wildlife Service.

The demise of the beaver brought about a major alteration of the Western landscape. The beaver is an integral part of riparian ecosystems, felling trees to create reservoirs where it builds its underwater lodges, thereby trapping alluvial sediments, providing opportunities for new plant growth, and increasing the diversity of wildlife habitats. Beaver dams help control seasonal flooding, a common occurrence on many Southwestern rivers and streams, thereby preventing erosion and downcutting of riparian channels. The reservoirs formed by dams also provide wetlands for migratory birds. Eventually these dams may be abandoned, and when they slowly break away and the pools dry up, great meadows of tall grass often grow up along the floodplain. These meadows sustain large populations of deer and elk, while the remnants of felled trees provide shelter for nesting birds and smaller animals.

The wholesale destruction of the beaver in the intermountain West disrupted these ecological relationships, and as a result erosion became a serious problem while the loss of habitat led to declining ungulate and bird populations. Removal of beavers or their dams, together with livestock grazing, has contributed to arroyo cutting and gullying of the landscape. As the channel cuts deeper and the gradient increases, the water table is lowered and surface sediments begin to dry out; gradually, the vegetation becomes composed of plants tolerant of drier conditions.

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