Rare Plant Stories

Heather Schneider, Santa Barbara Botanic Gardens

There are times when drying and storing seeds is not an option for the conservation of a plant species. This might be because the seeds cannot survive the freezing process, or maybe because the species no longer produces seeds in the wild. Researchers at the Santa Barbara Botanic Garden have been working with one such species, the Federally endangered Island Barberry, which no longer reproduces well naturally. While once found on several different channel islands, this species now occurs in a single location. 

Santa Barbara BG has established an ex-situ population of this rare species, allowing them to both conserve the genetic diveristy in a controlled environment, and use these plants to perform experiments without adversely effecting the small wild population. In 2019 these researchers began a propagation study using this ex-situ collection of island barberry to determine the best propagation methods for the species. Their experimental design had 4 variables. They planted cuttings in both the winter and the spring, they took cuttings from source material of different ages, they tested the use of a heating pad in propagation, and they tested different rooting hormone concentrations. Their results clearly defined the best practices for propagating the species. Cuttings should be made from old growth source material, and should be planted in the winter rather than the spring without the use of a heating pad. Rooting hormone is effective at both a 1:10 and 1:15 dilution. With this information, researchers have been very successful in propagating cuttings from the wild population for reintroductions.

This project is a great example of the value of living collections and horticultural expertise in rare plant conservation. An ex situ population was used to curate best practice recommendations for use by everyone involved in saving this species. From the boots on the ground on Santa Cruz Island to the dedicated staff and volunteers at SBBG, these efforts have ensured the Island Barberry a fighting chance at survival.

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Wednesday, September 16, 2020

Melissa K. McCormick, Dennis F. Whigham, Rachel Rock-Blake, Hope E.A. Brooks

North American Orchid Conservation Center (NAOCC) and Smithsonian Environmental Research Center (SERC)

Orchids are widely threatened and endangered worldwide, but efforts to conserve and restore them has been limited by not knowing about the pollinators and fungi they need to grow and reproduce. The absence of appropriate mycorrhizal fungi can limit where orchids grow, but little is known about how the abundance and diversity of appropriate mycorrhizal fungi can affect orchid growth and population dynamics. Light availability is also expected to affect population dynamics, but with orchid life stages occurring predominantly above- or below-ground it seems reasonable to hypothesize that different life stages would be driven by above- or below-ground factors. In particular, emergent, green, above-ground stages would be most impacted by light, while seed, protocorm, and dormant stages would be most affected by mycorrhizal fungi. We hypothesized that the distribution, abundance, and emergence of the globally rare temperate, terrestrial orchid, Isotria medeoloides, would be driven at least partly by their mycorrhizal fungi. We combined the use of specific PCR primers, quantitative real-time PCR, and spatially nested soil samples to measure the distribution and abundance of mycorrhizal fungi that associate with I. medeoloides and measurement of light availability and orchid growth in three distinct studies. We found that I. medeoloides distribution and emergence were affected by the distribution and abundance of their mycorrhizal fungi in the soil. In contrast, plant growth during the growing season and the likelihood of flowering the subsequent year were more affected by light availability. We conclude that orchid conservation and studies of the drivers of orchid population dynamics need to consider both the mycorrhizal fungi and light resources they require.

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Wednesday, March 4, 2020

James Lange and Jennifer Possley, Fairchild Tropical Botanic Garden

In the event of a hurricane, low elevation and proximity to the coast place Fairchild at high risk, and thus contingency plans must be in place to preserve our ex situ collections. Anticipating severe damage and extended power loss from Hurricane Irma, we took several measures to protect our conservation collections. We will discuss actions taken by conservation staff and lessons learned from this unique storm.

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Thursday, May 3, 2018

Sula Vanderplank, San Diego Zoo Global

The cross-border seedbanking initiative affectionately known as ‘Baja Rare’ targets around 65 taxa that are documented to be rare, threatened or endangered both sides of the MX/US border.  Many of these plants are far better-known in the US than in Mexico and as a result, our program has had to start with significant reconnaissance and surveys to find the populations historically documented.  In four cases (Streptanthus campestris, Navarrettia peinsularis, Erythranthe purpurea and Acmispon haydonii), expert botanical participation has revealed mis-identifications which make each of these three plants significantly rarer than previously assumed.  This project has also revealed at least one new highly restricted endemic taxon and multiple taxa worth of further study.  The role of the expert botanist is essential.

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Friday, October 9, 2020

Heather E. Schneider, Sean A. Carson, Santa Barbara Botanic Garden

Documenting the abundance and distribution of rare plants is a critical first step in the the conservation of wild populations. The methods used to map plants on the landscape have changed dramatically over time. Biologists have progressed from providing locality descriptions and marking plant locations on maps by hand, to using handheld GPS units, to the modern-day use of tablets and smart phones. Depending on the goals of a project, plants may be mapped using points, polygons and lines, or sometimes a combination of features, with varying degrees of accuracy. All of these variables can make it difficult to compare population dynamics over time. How can we determine wither a population really expanded or contracted, versus when it appears that way based on discrepancies in mapping technique or GPS accuracy? In an attempt to standardize rare plant mapping efforts on the Channel Islands, the Santa Barbara Botanic Garden worked with a group of collaborators to adapt and implement mapping protocols developed by Wildlands Conservation Science using ESRI’s Collector Application and a static spatial grid system. In 2019, we mapped the endangered Santa Cruz Island Dudleya (Dudleya nesiotica) using the protocols that we developed. Our results suggest that the abundance and extent of Santa Cruz Island Dudleya has increased since the last mapping effort in 2006, but we also laid the groundwork for more accurate comparisons in the future. The data generated using this method allow surveyors to map rare plants using consistent protocols that will improve the accuracy of comparisons of spatial distribution and abundance over time. While we are still fine-tuning our protocols and perfecting our methodology, this represents a significant step in improving data collection and analysis for rare plant surveys and monitoring.

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Thursday, October 8, 2020

Cheryl Peterson, Bok Tower Gardens

Dicerandra immaculata var. immaculata (Lakela’s Mint) (Lamiaceae) is a short-lived perennial endemic to the Atlantic Coastal Ridge. It has only a three-mile historical range and few remaining populations. Population modeling predicts near complete loss of plants within eight years unless habitat is improved enough to support large enough populations to withstand stressful events such as drought. Prescribed fire has not been implemented as a habitat-maintenance tool because of the dense urban interface. Regular volunteer workdays have instead been used to eliminate the biggest threats to the persistence of Lakela’s Mint by hand-pulling love vine, thinning the dense overgrowth, and herbicide-treating invasive grasses. A positive response of the mint population, tracked through bi-annual monitoring, is evident. Within one year, plants in an improved area increase in size and reproductive output by ~30%, and seedling recruitment has been observed in long-unoccupied plots. This project shows that regular workdays can be an effective strategy to rebuild Lakela’s Mint populations that are rapidly declining due to loss of quality habitat where implementing fire is not possible.

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Friday, October 9, 2020

Sheila Murray, The Arboretum At Flagstaff

Despite our best laid plans, conserving rare plants in their natural context produces many unforeseen challenges. This session shares the challenges associated with three rare plant reintroduction efforts in drastically different ecosystems: Florida, Arizona, and coastal California. 

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Friday, October 9, 2020

Tony Gurnoe, San Diego Botanic Garden

Baccharis vanessae, Encinitas baccharis, was originally described from a small population in Encinitas, California, just a couple of miles from the San Diego Botanic Garden (SDBG). The last individual to live within the garden was documented in 1997 and has not been observed since. The nearby type locality has also dwindled to just over two dozen individuals. Last year the team from the SDBG joined the efforts to conserve Encinitas baccharis by monitoring this population and collecting seeds from the few maternal lines available. Most of these seeds went into seed banks as part of the California Biodiversity Initiative and California Plant Rescue programs, but a cohort were also grown in SDBG’s nursery. This fall Baccharis vanessae will be reintroduced to the botanical garden with the goal of gaining a better understanding of how the species behaves in varying soil types and exposure scenarios. Meanwhile, SDBG staff continue to work with other populations, other institutions, and various other agencies toward the culmination of major in situ reinforcement and establishment of long-term management plans for Baccharis vanessae.

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Friday, October 9, 2020

Nina Rønsted, National Tropical Botanical Garden

Climate can play a critical role in plant physiological processes at all life stages, but investigations into climate effects often focus on only adult life stages. However, climate can influence seed development and germination, which can in turn strongly affect community dynamics. Native Hawaiian Metrosideros spp. (Myrtaceae; ʻōhi‘a,; 13 taxa) are the most dominant and ecologically important trees in mesic and wet rainforest ecosystems of Hawaiʻi. Aditionally, ʻōhi‘a are the most bioculturally important native plant in Hawai‘i. Recently, new fungal pathogens are causing rapid ʻōhi‘a death (ROD). As ʻōhi‘a are foundational species, ROD threatens the native forests that compose the majority of intact Hawaiian ecosystems. Making the most of Covid19 disruptions of our daily work, we used initial seed viability data from germination experiments routinely conducted by National Tropical Botanical Garden’s Seed Laboratory to explore if seed viability is correlated with collection locality and environmental variables. We included seed viability data of the most widespread and common taxon, M. polymorpha var. glaberrima, from 86 collection sites across Kauaʻi Island. Correlation of seed viability with environmental data from the Online Climate Atlas of Hawaiʻi was explored using linear models in R and suggest initial seed viability is correlated with mean temperature of coldest quarter and to a lesser extent with precipitation of warmest quarter reflecting the complex topology of Kauaʻi. As ROD threatens ʻōhi‘a across the islands, knowledge of these climatic effects on seed germination can be used as a proxy for understanding the health of populations across the distribution range and at its extremes. Linking seed viability information with environmental variables and locality can further help inform conservation priority planning as well as guide seed collection for safeguarding in seed banks.

Date Recorded: 
Friday, October 9, 2020

Sabine Wintergerst, Fairchild Tropical Botanic Garden

The only known remaining populations of the Keys partridge pea (Chamaecrista lineata var. keyensis) are found within the imperiled pine rockland habitat on two islands of the Florida Keys. Like other low-lying islands, the Florida Keys are especially threatened by sea level rise. As a consequence, soil salinity levels will likely rise as well, first in areas closer to the coast but eventually salinization will also reach areas further inland. Additionally, more frequent and higher storm surges are also predicted which will temporarily inundate part of the islands in saltwater. Previous research has shown that the impact of 2005’s Hurricane Wilma negatively affected populations of the Keys partridge pea. However, the effect of increased salinity on seed germination and seedling establishment has not been investigated. We established an ex situ collection through which seed bulking provided enough seeds to use for experimental trials which were conducted with the help of high school students as part of Fairchild’s BioTECH internship program. The results show that seed germination remains high at low levels of salinity (<10ppm) but decreases substantially when salinity becomes more similar to ocean water (~30ppm). Although seedling survivorship is also high at low levels of salinity (<10ppm) it is important to note that even at 5ppm, 20% of seedlings died within 2 months of exposure. Above 20ppm, seedling survivorship declined rapidly revealing how even short exposures to ocean water could have detrimental effects on juvenile plants. Our results show how seedlings are especially threatened by storm surges, but further research is needed to investigate how well seeds and seedlings can recover as soil salinity is alleviated by precipitation. Knowing how these critical life stages of the Keys partridge pea are affected by an increase in salinity can inform the future population trajectory and help with management and/or restoration planning.

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Date Recorded: 
Friday, October 9, 2020