Rare Plant Treasure Hunt

Map of rare plant occurrences documented throughout California in the frsti 3 years of the project. Click to view larger.

Project Background and Results

CNPS and the California Department of Fish and Wildlife (DFW) 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 focused time and energy on forests with high concentrations of plants in need of current data in 2012.

Rare plant occurrence type by year, for the first 3 years of the project.

The CNPS Rare Plant Treasure Hunt has harnessed the efforts of over 200 volunteers that have spent over 8500 hours on the project, and we've already gathered data on over 1,450 rare plant occurrences. We updated 477 occurrences statewide in the 2012 field season. 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 40% of the occurrences found in 2012 were previously unknown! About 60% of the plants documented so far are CNPS Rank 1B plants, which are the rarest plants in California. See our full results from 2012 in the figure above.

Some highlights from the 2012 field season

From the desert:

• Desert explorers re-located the type locality of the Panamint daisy (Enceliopsis covillei), the flower that adorns the CNPS logo. After a long hike in the hot desert (95 degrees in the morning!), when they had nearly given up on their quest, RPTHers caught a glimpse of the daisy's bright yellow flowers. The population had not been seen in 121 years, and, except for some insects that had been chewing on the petals, the plants were doing just fine!
• Rare Plant Treasure Hunters made three trips to this Sonoran Desert mountain range, and were treated with some amazing discoveries. Every stop they made and every canyon they explored yielded more rare plant information, and they came away with data on more than 50 rare plant populations. At the base of the mountains, Duncan Bell recognized an undescribed subspecies of Linanthus!
• Range extension for common plants - Rare Plant Treasure Hunters in the desert gathered important information not only on rare plants, but on some common plants as well. Seven species were recorded for the first time in Imperial County, including Calycoseris parryi, Penstemon spectabilis, Eriodictyon crassifolium, Trifolium wildenovii, Plagiobothrys tenellus, Eriogonum nudum, and Claytonia perfoliata. This is great example of how RPTHers can fill in the gaps in our knowledge of the California Desert beyond just the rare plants!
  

From the National Forests:

• Discovery of a new occurrence of Jack's wild buckwheat (Eriogonum luteolum var. saltuarium) in the Stanislaus National Forest. This plant was previously only known from three populations, and two of those populations may be extirpated already.
• RPTHers found three populations of Tulare rockcress (Boechera tularensis), a difficult-to-ID rare plant that was first described in 2007, with only one recent occurrence before our surveys. Other RPTHers will continue to search for it in 2013!
• Volunteers re-located and mapped the only known occurrence of Shevock's rockcress (Boechera shevockii) from The Needles in the Sequoia National Forest. There was concern that the only population could have been damaged in a recent fire, but fortunately it was not harmed.