Seed Banking Rare Plants
Saving endangered plants–one seed at a time
Curator and Conservation Officer Clare Loughran
Behind the scenes, the Garden is involved in a major collaborative study in the field of conservation science! In 2023, the Center for Plant Conservation (CPC) received an Institute of Museum and Library Services (IMLS) grant from the federal government to develop protocols for maintaining the genetic diversity of seed collections across generations and climatic regions. The goal of the study is to measure how selection in the nursery over two generations may affect genetic diversity, compared to wild-collected lines, and to develop research-based protocols for augmenting seed in the nursery for conservation purposes, such as re-banking and reintroduction.
A Unique Collaboration for Plant Conservation
The CPC has partnered with California Plant Rescue (CaPR), a coalition of botanical institutions in the state that includes the UC Botanical Garden (UCBG), to grow thousands of rare plants native to California. Fifteen different species of rare native plants were selected for the study, with the goal of growing five plants from each of 50 maternal lines per species. Each species is being grown at both inland and coastal locations to facilitate comparisons between different climatic variables.
Seed collections Play a Crucial Role in Conservation Efforts
By storing seeds in seed banks, we can safeguard the genetic diversity of plant species, especially those that are rare or threatened. However, some collections are small and contain fewer seeds than the recommended amount for long-term conservation and restoration. When collections are too small, they may lack sufficient genetic diversity, which can affect their long-term viability.
The preservation of genetic diversity is a fundamental aspect of plant conservation. In the wild, plants rely on natural processes such as pollination and seed dispersal to maintain their genetic integrity. However, in a controlled nursery environment, these processes can be influenced by factors like limited space, changes in pollinators, and a further reduced gene pool. By collaborating with our partner institutions, we can provide a broader range of genetic material for study and make comparisons across many species.
Focusing on Two Species: Contra Costa Goldfields and Santiago Peak Phacelia
For this study, UCBG is working with California Botanic Garden in Claremont to grow Contra Costa goldfields (Lasthenia conjugens) from the daisy family (Asteraceae) and Santiago Peak phacelia (Phacelia keckii) from the waterleaf family (Hydrophyllaceae). Both species are extremely rare and found only in California. The Contra Costa goldfields is a vernal pool species from Northern California that have been eliminated from many of its historical populations and is under threat from development and habitat alteration. The Santiago Peak phacelia grows in chaparral and closed-cone coniferous forests and is known only from the Santa Ana and Aqua Tibia Mountains in Southern California. Propagation for the study began in late 2023 and will continue for two years, allowing two generations of each species to be grown in the nursery.
Propagator Susan Malisch with the Contra Costa goldfields in the UCBG nursery
Our expert plant Propagator on staff, Susan Malisch, leads the effort in the nursery, with support from a team of students and volunteers. Nursery conditions are carefully controlled to provide the plants the best chance of thriving. The study requires us to ensure that our propagation techniques closely match those used by California Botanic Garden. Through this collaboration, we’ve not only refined our methods but also strengthened our relationship with this key Southern California garden.
Meticulous Data Collection and Monitoring is Required
Many aspects of the production phase are being meticulously tracked, from weather and watering schedules to germination, transplant dates, and counts of stems, flowers, and seed production. Our Assistant Curator, Sophia Warsh, plays a vital role in data collection and monitoring the plants’ progress, recording both phenological and morphological data, with the assistance of dedicated students and volunteers. At the end of each growing season, seeds from each species are collected by maternal line, cleaned, quantified, and stored in our seed bank. Data collected throughout the study will be shared with our partners and analyzed, leading to a scientific publication that may influence methods and guidelines related to seed bulking for conservation practitioners.
Assistant Curator Sophia Warsh recording data for the Contra Costa goldfields growing in the UCBG nursery
Collaborative scientific studies like this are essential for ensuring that California’s native plants are preserved and can thrive in the face of environmental changes. UCBG is proud to work with partners across the state and beyond to further our mission of plant conservation. The Contra Costa goldfields grown for this study will be on display for public viewing later this spring at the Garden’s front entrance.
We thank all the students and volunteers who devoted countless hours of their time and contributed to the success of the project!
Seed banking at the Garden
Seed banking is an important conservation method used to preserve seeds for research or reintroduction efforts. Seed banking is a painstaking effort that includes cleaning, drying, and storing seeds, using methods that preserve seed viability, so they can be used in the future.
Banner: Contra Costa goldfields (Lasthenia conjugens)