The Etiwanda Fan

The Etiwanda Fan is located in the southwest corner of San Bernardino County California in the foothills of the San Gabriel Mountains and north of the City of Rancho Cucamonga. Although much of the fan has been altered by flood control practices, sand mining, and urban development, large areas of the Etiwanda Fan are minimally disturbed by human activities.

A large portion of the Etiwanda Fan is protected by the North Etiwanda Preserve (see map below). The North Etiwanda Preserve was established on 24 February 1998 as mitigation for the State Route 30 improvements project by cooperative agreement among San Bernardino Area Governments, San Bernardino County Special Districts, California Transportation Services, California Department of Fish and Game, and the U. S. Fish and Wildlife Service. The core preserve area consists of a 763 acre parcel of land located on the Etiwanda Fan in the foothills of the San Gabriel Mountains, north of Rancho Cucamonga and adjacent communities. Since 1998, significant amounts of acreages that surround the Preserve have also been set aside for permanent natural habitat conservation. The Etiwanda Preserve Management Commission and San Bernardino County Special Districts manage the Preserve and surrounding conservation lands. The Preserve Commission and County Special Districts continue to seek opportunities for expansion of the Preserve and the surrounding habitat on the Etiwanda Fan.

Habitats on the Etiwanda Fan are composed of Oak Woodland, Chaparral, Coastal Sage Scrub, Alluvial Fan Sage Scrub, White Alder/Willow Riparian, Sycamore/Oak Riparian, and non-native grassland. Most imperiled of these is the Coastal Sage Scrub habitat and is sub-association of Alluvial Fan Sage Scrub, which are state threatened and rare natural communities. It is estimated that 75% to 90% of all Coastal Sage Scrub habitats have been extirpated from Southern California and the Etiwanda Fan is one of three remaining expanses of Alluvial Fan Sage Scrub. In addition, the Preserve and surrounding lands also contain significant amounts of other rare and threatened habitats that include Sycamore Alluvial Woodland, California Walnut Woodland, and Fresh Water Marsh.

The Etiwanda Fan also encompasses significant historical and cultural resources related to the local area history. The land within and adjacent to the Preserve has important historic and contemporary religious significance to the Gabrielino-Shoshoni Nation.

The Etiwanda Fan is home to a number of endangered, threatened, and sensitive species that include, but are not limited to, the Coastal California Gnatcatcher, Southwestern Willow Flycatcher, Least Bell’s Vireo, San Bernardino Kangaroo Rat, Bell’s Sage Sparrow, Rufous-crowned Sparrow, San Diego Horned Lizard, Los Angeles Pocket Mouse, Plummer’s Lily, and Mariposa Lily.

From 1990 through 2002, the Biological Sciences Division of the San Bernardino County Museum conducted wildlife surveys within a portion of the intact habitat, primarily within the boundaries of the North Etiwanda Preserve (see map below). The most intensive field studies were conducted from mid March 1998 through mid March 2002. The pages within this site provide an overview of the North Etiwanda Preserve, an overview of the plant communities found within the Preserve, and a list of species known to be present within the last ten years, with additional information for a selected subset of those species.