Habitat Conservation

The Western Riverside County Regional Conservation Authority (RCA) was created in 2004 to achieve one of America’s most ambitious environmental efforts, the Riverside County Multiple Species Habitat Conservation Plan (MSHCP).

How Does it Work?

The Habitat Conservation Plan has its own language: core areas, linkages, criteria areas, rough steps, and more. The pioneering qualities of the MSHCP meant inventing a new vocabulary to describe basic concepts.

The lands described by these words form the basic ingredients needed to protect and preserve the 146 species of rare, threatened, and endangered plants, birds, and animals and acquire the land needed for wildlife reserves that will allow the MSHCP to succeed.


Core Areas have the right resources to provide live-in habitat and support the life history requirements of one or more species covered by the MSHCP. Some of the Core Areas were part of the 347,000 acres of public or quasi-public lands that formed initial reserves.

Linkages are like bridges. They connect the core areas. Some linkage areas are big enough to host living areas for protected animals. Linkages described as “constrained” may be hemmed in by existing patterns of development. They may work well as pathways linking core areas, but not as living spaces.

Non-contiguous Habitat Blocks are areas already set aside because specific species live there or because they were established in past conservation efforts. Proposed Non-contiguous Habitat Blocks are usually identified as important for acquisition because of the species found there.

The Criteria Area is at the heart of the MSHCP. This land is habitat adjoining the Core Areas, Non-contiguous Habitat Blocks, and Linkages. Species either live there or travel through when moving from one area of conserved habitat to another. The acres needed to meet the MSHCP’s goal of a half-million acres of reserves comes from this land.

Cells are smaller units within the Criteria Area that allow RCA to more easily organize and keep track of both development and habitat acquisition.

Rough Step Areas are meant to help RCA evaluate whether conservation of specific small habitats is occurring “roughly in step” with development approvals. Each of the nine zones called Rough Step Areas were established according to weather patterns, geography, soils, and geology found there. The 9 Rough Step Areas are home to 37 plant communities.

The MSHCP identified 20 Core Areas, 10 Non-contiguous Habitat Blocks, and 28 Linkages between areas of habitat as the system of conserved lands that would meet the MSHCP goals for habitat preservation and species protection. The MSHCP also established conservation targets within each of the member cities and each of the 16 Area Plans in Western Riverside County covered by the Riverside County General Plan.