
Now is the Time to Do Rare Plant Surveys
With the record-setting storms throughout California in January 2023, now is the time to conduct rare plant surveys, as many species are likely to bloom this year Plant growth and its relationship to climate is very nuanced, but in general the higher the rainfall, the more likely it is that rare plants will grow and bloom making them detectable during surveys. Dudek Botanist Megan Enright said, “We often receive comments from the public, resource agencies, and non-governmental organizations, about weather patterns and rare plant surveys, stating that rare plant surveys need to be re-done because the weather at the time wasn’t appropriate for obtaining adequate data.” If you are considering doing a rare plant survey on your project site in the next few years, consider doing it this year to maximize detectability. Botanist Megan Enright gives the following tips to ensure you get the most from your surveys.
Plan for an Effective Rare Plant Survey

1. Determine whether a spring, summer, fall, or winter rare plant survey is needed. If a survey is needed in the next couple of years, it may be better to complete it this year to take advantage of the rainfall and reduce the potential for negative comments from the public during CEQA/NEPA public review or permitting.
2. Plan ahead and contact a biologist to determine what rare plant resources may be present on or within a 10-mile buffer of your project site. A biologist can provide an initial assessment of the potential rare plants that might affect the project and help devise a plan for conducting the appropriate studies to get you through the regulatory process.
3. Determine which surveys are required. Specific vegetation communities and other factors may necessitate different rare plant surveys, each with its own timing and protocol. Missing one of these survey windows can adversely affect agency coordination and project roll-out, or lead to additional surveys down the road.
4. Check reference populations because rare plant species bloom at slightly different times each year depending on temperature, rainfall patterns, elevation, and other environmental factors. Reference population checks involve locating known populations of rare plant species during a time frame when they are known to be blooming or exhibit other characteristics that enable species identification. Observing reference populations during these key time periods can provide assurance to the lead agencies and resource agencies that these species are accurately identifiable.
5. Check to see if your property is located within a habitat conservation plan (HCP) area. Across San Diego, Orange, Riverside, Contra Costa, and Sacramento counties, for example, there are numerous conservation planning efforts in place designed to streamline protection efforts for a number of sensitive plant species.
Communicate Often throughout the Process
6. Communicate often with your biologist to keep rare plant surveys moving forward. Sharing property information such as any previously attained reports can provide some insight into previous survey results and habitat constraints, which can save time and money.
Execute your Rare Plant Survey
7. Ask for a floristic survey. Resource agencies and non-governmental organizations prefer floristic surveys, which require the identification of individual species and assessment of the abundance of species. This type of survey requires additional skill and experience as a botanist.
8. Ensure rare plants are mapped using sub-meter accuracy GPS units and obtain population extent and abundance. Mapping the extent of the rare plant allows you to avoid them, if possible. Mapping the abundance allows you to assess the magnitude of the impact to determine significance for non-listed species and “take” for state- and federally listed species.
Dudek biologists conduct floristic surveys, collecting data on all plant species located on your property so that they can be accurately and thoroughly mapped. We understand the relevant local policies, permitting policies, and habitat conservation planning efforts taking place in your region. Our biologists regularly attend workshops and seminars, as well as consult state and federal resource databases to stay current on the latest scientific information regarding species distribution, species life history, and survey protocols.
Contact us for more information on efficiently managing your rare plant survey this year!