Rare Plant Treasure Hunt

Population of Johnson's pineapple cactus (Sclerocactus johnsonii, Rank 2.2) that was re-discovered by Treasure Hunters had not been documented since 1941! © Amber Swanson and CNPS

Project Background and Results

CNPS and the California Department of Fish and Game (DFG) track California’s rare plants in the California Natural Diversity Database (CNDDB), which has now provided us with a map of more than 32,000 rare plant occurrences across the state.  Right now, nearly half of those occurrences are historical, meaning that they have had no documentation in at least 20 years.  Getting up-to-date information on our rare plants is critical to understanding which populations are still present and which species need our closest attention in order to ensure their long-term conservation.

In addition to the need for more recent data, this project focuses on the California deserts because of the imminent threats facing these biodiversity hotspots.  Many solar energy projects have been proposed throughout the desert, often in areas where few botanists have stepped foot, and un-described species could even be present! 

Because nearly 50% of California Rank 1B and 2 plants occur on USDA Forest Service lands we will focus time and energy on forests with high concentrations of plants in need of current data in 2012.

That’s where the Rare Plant Treasure Hunt comes in.  Over 200 volunteers have spent over 6000 hours on the project, and we’ve already gathered data on nearly 1,000 rare plant occurrences.  With more participants, we can work toward updating the approximately 15,000 historical occurrences in the CNDDB.  Not only have our volunteers documented many historical occurrences, they’ve also made important new botanical finds – about 36% of the occurrences found in 2011 were previously unknown!  About 70% of the plants documented so far are CNPS Rank 1B plants, which are the rarest plants in California.  See our full results from 2011 in the figure above.

Some highlights from the 2011 field season

From the desert:

• Rediscovery of the westernmost naturally occurring Saguaro, Carnegiea gigantea, rank 2.2, in the United States. In 1986 this cactus had been spotted by airplane in Imperial County and a general location had been recorded. We found the single 25 foot tall, five armed plant while surveying on the ground this year and took GPS coordinates of the site.
• Finding six new populations of Linanthus maculatus, Little San Bernardino Mountains linanthus, rank 1B.2. This tiny plant, a member of the Phlox family, is just an inch or less tall! We barely caught the plants at the very end of their blooming and fruiting season; in another week they would have been gone. We also made the first collection of seed ever taken from this rare plant, which will be preserved at the Rancho Santa Ana Botanic Garden seed bank.
• Locating the first known population of the little Liveforever, Dudleya abramsii var. affinis on BLM land. There were only 12 populations known of this plant and all were found only on the north side of the San Bernardino National Forest.

From around the state:

• Discovery of what will likely be the second known occurrence of Botrychium paradoxum, paradox moonwort, in California. This plant is not yet ranked by CNPS, but it is sure to make its way into the Rare Plant Inventory in the coming months. We are still awaiting genetic testing by a moonwort expert to confirm the identity of this very unusual fern.
• The Rare Plant Treasure Hunt took a survey out on the water for the first time. At the Cosumnes River Preserve in Sacramento County, volunteers paddled through the Delta in nine different canoes and kayaks, mapping twenty-five colonies of Sagitarria sanfordii, Sanford’s arrowhead, and two populations of Hibiscus lasiocarpos var. occidentalis, woolly rose-mallow, both Rank 1B.2.
• Volunteers from the North Coast Chapter of CNPS found populations of Cuscuta pacifica var. papillata, Mendocino dodder, a parasitic plant that was just added to rank 1B.2. Previously, this California endemic had only been known from six populations, none of which had been documented more recently than the 1980s.