Locally Rare Plants

Preserving genetic diversity

Credit

Protection is needed

CNPS has tracked and secured legal protection for California’s rare plants since the late 1960s. Today, more than 2,000 taxa are currently listed as rare in the CNPS Inventory of Rare Plants. However due to the large size of our state, many plant taxa that are too common from a statewide perspective to include in the CNPS Inventory are nonetheless declining rapidly in the wake of the rapid alteration and loss of natural habitats. These locally rare species are critical to the preservation of regional and local scales of genetic diversity.

Locally rare plants play an important role in helping to preserve the diversity of the species, as well as the gene pool of local flora.

These plants also preserve the potential for the species to undergo speciation events and are often of scientific or historical importance.

What are locally rare species?

The scientific community considers these plants to be sensitive, unique, or occurring at the limits of their natural range within a specific region (also called peripheral populations). Species-specific characteristics, available suitable habitat, as well as land use activities and practices, all play a role in determining whether a species that is relatively common in one part of its range is rare in another part of its range.

Peripheral populations as refugia

Many plant populations are considered locally rare because they occur on the geographic edge of the species range. These peripheral populations are important because they often show morphological and ecological divergence and can be genetically distinct from the main population of the species — character traits that help them contribute to the long-term survival of a species. Even when widespread taxa have been brought to near extinction, peripheral populations can act as refugia for species.

Legal protection

Because many laws, including the California Environmental Quality Act (CEQA), are implemented at the local level (county or city), CNPS encourages botanists and volunteers to look at locally rare plants as well as statewide. Article 9 of CEQA states that “special emphasis should be placed on environmental resources that are rare or unique to that region.”

Clarkia tembloriensis ssp. tembloriensis
Clarkia tembloriensis ssp. tembloriensis is a locally rare plant in Alameda County known only from Corral Hollow near the Lawrence Livermore Lab. However, this species is known from at least 5 other counties in California and would therefore be considered a locally rare species but would not be considered a California rare species.

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It's a fact

Locally rare plants play an important role in helping to preserve the diversity of the species, as well as the gene pool of local flora. Locally rare plants also preserve the potential for the species to undergo speciation events and are often of scientific or historical importance.

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Learn about becoming a member of the CNPS Locally Rare Working Group.

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Act locally

Here’s how to start a local rare plant program for your chapter.

Local Program Guide

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