Mother Lode Field Office

Ione Manzanita ACEC

General Information

The Ione manzanita is an endemic plant of the central Sierra Nevada foothills mostly limited in distribution to soils derived from the unique Ione Formation near the community of Ione in Amador County.

The Ione Formation is comprised of fluvial , estuarine, and shallow marine deposits of Eocene age. Soils of the Ione Formation are characterized by low fertility and pH levels and high aluminum concentrations. Recent reserch suggests a correlation between some edaphic factors, primarily soil development and acidity, and the distribution of the Ione manzanita.

The Ione manzanita has declined in recent years due primarily to mining of the valuable clays and sands associated with the Ione Formation, and to other land developments. These activities have resulted in the reduction and fragmentation of the species' habitat. In addition, recent severe die-offs of the plant have occurred throughout its restricted range, possibly contributing to further declines of the species.

The Ione manzanita is an obligate seeder. Unlike other manzanitas, it can be killed outright by fire and is entirely dependent on seeds stored in the soil or dispersed to the site for stand regeneration.

The Ione manzanita is currently classified by the U.S. Fish and Wildlife Service as a candidate for listing under the 1973 Endangered Species Act (as amended). This is the Services's highest priority classification for listing a species under the Act. It is also listed by the California Native Plant Society (CNPS) under List 1B, including those plants which are rare, threatened, or endangered in California or elsewhere.

Because of the species' recent decline and highly localized range, the Bureau designated the subject area as an Area of Critical Environmental Concern (ACEC) in 1988. The Ione Manzanita ACEC is one of only two designated areas where the plant is under protective management by public agencies. A second area, the Apricum Hill Ecological Preserve, located 3 miles south of Ione, is managed by the California Department of Fish and Game (DFG).

For additional information on the Ione Formation, see the BLM  Ione Soil ACEC.