San Benito evening primrose. Photo courtesy of the Bureau of Land Management.
San Benito evening primrose. Photo courtesy of the Bureau of Land Management.

On Feb. 2, the U.S. Fish and Wildlife Service announced the San Benito evening primrose (Camissonia benitensis), a small flowering plant native to San Benito and surrounding counties, is being removed from the federal list of endangered and threatened wildlife and plants. 

The service had listed the plant as threatened under the Endangered Species Act (ESA) in 1985 because of ongoing threats from motorized recreation activities and commercial mining operations. 

At that time, the species was documented in nine locations in a small area of San Benito County. Annual surveys have confirmed that the plant is now found in more than 100 areas across multiple watersheds in portions of San Benito, Monterey and Fresno counties. 

The service said in its release that “understanding the plant’s ecology and habitat has improved due to the diligent efforts of the Bureau of Land Management [BLM] to survey, study, and conserve habitat for the San Benito evening primrose over the last three decades.”

A post-delisting monitoring plan has been developed to monitor the plant’s status over the next five years to verify that the species remains safe from the risk of extinction. 

In their release the service said, “working with others is essential to protecting ecosystems that benefit society as a whole. The service uses the best available science to make ESA determinations and regularly engages conservation partners, the public, landowners, government agencies and other stakeholders in its ongoing effort to identify innovative strategies for conserving and recovering protected wildlife, plants and their habitats.” 

BenitoLink asked Todd Lemein, botanist with the U.S. Fish and Wildlife Service in Ventura, the following questions regarding the species. 


What was the historic range of the plant? 

San Benito primrose historically occurred in serpentine soils of San Benito County, in areas that are now part of the Clear Creek Management Area managed by the Bureau of Land Management. The current range of San Benito evening primrose is from the southeastern portion of San Benito County, the western edge of Fresno County, and the northeastern edge of Monterey County. 

How does the service define “native” in biological terms? 

The term native in biological terms typically describes plants and animals that were present on the landscape prior to European colonization. In other words, they were not introduced to the landscape following European colonization. San Benito evening primrose was first described in the 1960s and is known to occur only in San Benito, Fresno and Monterey Counties.

Has the plant been planted/propagated to help its recovery? 

To support recovery efforts for the plant, San Benito evening primrose seeds were planted at six locations in the early 1990s in areas where it was known to occur in the Clear Creek Management Area. Again in 2008 and 2012, seeds were sown in areas with serpentine soils where the plant could re-establish. These reintroduction efforts resulted in establishment of colonies of San Benito evening primrose. In 2010, an additional two acres of habitat was restored near stream terraces that had been degraded from former off-highway vehicule use and mining operations. Restored areas now support San Benito evening primrose. The restoration efforts included restoring vegetation, decreasing soil compaction, removing debris and erosion control measures. 

Does the plant exist on private lands as well? 

The plant exists on both public and private land. The Bureau of Land Management worked with private landowners to survey for San Benito evening primrose, which helped scientists understand the plant’s ecology and habitat needs. For more details on BLM’s survey efforts, a good point of contact would be Serena Baker with the Bureau of Land Management’s Central Coast office. Her email is

How are populations doing? 

The majority of San Benito primrose plants are found in San Benito County, with smaller populations in Fresno and Monterey counties. Annual surveys across the species range confirm that the plant now resides in more than 100 areas across multiple watersheds in portions of San Benito, Monterey and Fresno counties. Since 1998, BLM surveys indicate a mean of approximately 9,690 individual plants from data collected across a subset of populations. Surveys indicate the population has remained generally stable from 1998 to 2020. 

What were the nine locations in which the plant found when it made the endangered list? Can you cover the 100 areas where the plant is found now?

The nine locations were within the Clear Creek Management Area within the Serpentine Area of Critical Environmental Concern [see figure below].

San Benito evening primrose range map. Courtesy of U.S, Fish and Wildlife Service.
San Benito evening primrose range map. Courtesy of U.S, Fish and Wildlife Service.

Can you explain the post-delisting monitoring plan?

The post delisting monitoring plan is a commitment to continue monitoring the status of the plant over the next five years, to ensure the population trends continue to show stability. Monitoring by BLM will include an annual census of abundance of a selection of occurrences on public lands in all habitat types, annual disturbance monitoring, seed bank quantification, and evaluation of woody vegetation. 

Will monitoring plants on private land look different than monitoring it on public land? 

Monitoring will be conducted on public lands managed by the BLM. 

Do you see changes such as ongoing drought or climate change disrupting the continued recovery of this species? 

We can never be certain how a species will respond to climate change since often the tolerance to climate change is unknown. Similarly, how climate change will manifest (e.g. the amount and timing of precipitation, daily temperatures, first freeze, etc.) can be modeled but is not a known quantity. Closely related species occupy a range of climatic conditions and we concluded that climate change is not a threat to the species’ persistence in the foreseeable future. Through disturbance monitoring in the post-delisting monitoring plan, we will continue to monitor potential anthropogenic disturbances.

The Fish and Wildlife Service accepted public comments on the proposal to delist the San Benito evening primrose from June 1 to July 31, 2020. The final ruling, which is effective March 7, and the post-delisting monitoring plan are here


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Carmel has a BA in Natural Sciences/Biodiversity Stewardship from San Jose State University and an AA in Communications Studies from West Valley Community College and she reports on science and the environment....