WRA Botanists Go Above and Beyond In Search of Rare Plants

Spring 2016 wildflower bloom in the Caliente Range, Carrizo Plains National Monument. Photo Credit: Scott Yarger

Spring 2016 wildflower bloom in the Caliente Range, Carrizo Plains National Monument. Photo Credit: Scott Yarger

WRA botanists are often tasked with determining what, if any, rare plant species have potential to occur on a project site. To do this, we start by searching databases for known rare plant occurrences in the vicinity and then compare the habitat requirements of each species to the conditions found on the project site. In some cases, data on the habitat requirements for rare species are vague and may include only broad habitat descriptions such as “cismontane woodland” or “valley and foothill grassland”. This is where personal experience and expert knowledge prove invaluable. When it comes to making these challenging calls about a species’ potential to occur and detecting sometimes elusive and inconspicuous species during a rare plant survey, there is no substitute for having previously observed the target species in their native habitats.

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WRA has a strong contingent of botanists with extensive experience throughout California. WRA botanists have collectively observed more than 400 plant species listed as rare or endangered by the California Native Plant Society (CNPS), and the list is constantly growing. Our current individual leader is Aaron Arthur, a prolific Calphotos photographer, whose life list is approaching 200 rare plant species, and we have several other staff who have reached or are approaching triple digits (including Scott Batiuk, Cara Scott, Chris Gurney, Scott Yarger).

Inaugural Botany Hike Series

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While many of these species were observed during project work, WRA botanists are passionate about their work and go out of their way to find and observe rare plant species in their free time. Small groups of WRA botanists have been meeting on weekends to go botanizing for many years, but 2016 marked the first year of our official “Botanical Hike Series.” Throughout the spring and summer months, WRA botanists, along with other staff, family, and friends have been meeting every couple of weeks to visit botanical hot spots around the San Francisco Bay Area and beyond. This year we visited Mt. Tamalpais (Marin County), the Carrizo Plain (San Luis Obispo County), Point Reyes (Marin County), Jepson Prairie/Elsie Gridley Mitigation Bank (Solano County), Bohemian Ecological Preserve (Sonoma County), Walker Ridge (Lake County), Bear Valley (Colusa County), Mt. Diablo (Contra Costa County), Antioch Dunes (Contra Costa County), and the Springtown Preserve (Alameda County).

WRA’s Botanical Hike Series builds on our already strong expertise in botany. Many rare plant species have unique microhabitat requirements that are not well documented and can be difficult to describe. By visiting these unique habitats and observing rare plants in the wild, WRA botanists are able to learn the subtle microhabitat requirements of rare species and hone their search image for these species. After observing multiple occurrences of a rare plant species, one begins to recognize the suite of other species that are commonly associated, as well as unique soil characteristics and other indicators of habitat suitability. Once this expert knowledge is developed, it is often possible to “sense” that a certain rare plant species is likely present before seeing it, only to find it minutes later.

Education and Public Outreach

WRA’s botanical experts frequently share this knowledge with the general public through leading wildflower hikes and hosting workshops. For the past decade, Aaron Arthur has participated and led wildflower hikes for the CNPS Milo Baker Chapter (Sonoma County), LandPaths, and others at Ranchero Mark West, Annadel State Park, Willow Creek State Park, Cooley Ranch, North Bay Mitigation and Conservation Bank, Pepperwood Preserve, and Bohemia Ecological Preserve. Recently, recognized serpentine ecologist Tanner Harris teamed with Aaron Arthur to develop and host a workshop focusing on serpentine habitats using Bohemia Ecological Preserve as their outdoor classroom. Participants were primarily docents for LandPaths who learned about the formation of ultramafic rock, soil formation, plant physiology and ecology, and vegetation and floristics of serpentine habitats. These docents now share what they have learned with the frequent visitors to the Preserve. Read more about the workshop here. 

WRA’s Tanner Harris (left) and Aaron Arthur (right) leading a serpentine ecology workshop at LandPaths’ Bohemia Ecological Preserve.

WRA’s Tanner Harris (left) and Aaron Arthur (right) leading a serpentine ecology workshop at LandPaths’ Bohemia Ecological Preserve.

In 2017, WRA botanists will continue and expand on this tradition of public outreach. We hope to host additional publicly available hikes and workshops, as well partner with the CNPS Rare Plant Treasure Hunt Program to collect and share additional data. Stay tuned for more information on how you can join our team of passionate botanical experts in the wilder parts of the Bay Area and beyond!