Conditions of rangelands before 1905
Contribution to Book
Volume II: Assessment of scientific basis for managment options
University of California, Davis, Centers for Water and Wildland Resources
Paleoecological sources indicate that the location and extent of Si- erra Nevada rangelands have varied significantly during the last 20,000 years. Modern vegetative associations are recent, with mon- tane wet meadows appearing during the last 3,000 years. A late Pleis- tocene sagebrush grassland existed where montane and subalpine forests occur today. In the central Sierra a pattern of deglaciation and vegetative response was repeated at different times depending on location, from alpine grassland to a diverse mixture of conifer and shrub species in an open forest structure. The Holocene began with a decline in mesic species and increased charcoal and oak pollen, indicating a warming trend. A cooler, wetter climate followed as mesic conifers reappeared and evidence of fire decreased.
Historical accounts indicate that highly productive rangelands ex- isted when Europeans arrived. Large ungulate populations were present, and perennial grasses dominated foothill rangelands. Nu- merous observers reported severe overgrazing by livestock in the late 1800s, due in part to a lack of regulation of the common range- lands. Livestock management contributed to annual grassland con- version on the west side and to juniper woodland expansion on the east side of the range.
The abundance of a diverse assemblage of large grazing mam- mals at the end of the Pleistocene indicates that Sierra Nevada range- lands were highly adapted to intense grazing pressure and that animal disturbance was an integral part of this highly productive system. This evidence argues for a recognition that well-managed animal dis- turbance is as vital as well-managed fire to ecosystem health and sustainability.
Kinney, William, "Conditions of rangelands before 1905" (1996). Aspen Bibliography. Paper 1734.