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Why Our Living Collection Matters
By: Christina Varnava, Living Collection Curator
The towering bigcone Douglas fir (Pseudotsuga macrocarpa) in the Manzanita Section. The colorful irises (Iris spp.) surrounding the Meadow Section. The elusive California peony (Paeonia californica) on the Porter Trail. The appearance of these plants is very different, but they are all part of the Living Collection at Santa Barbara Botanic Garden. The Living Collection is one of the Garden’s three American Alliance of Museums accredited collections, along with the Blaksley Library and the Clifton Smith Herbarium. But what exactly is a living collection?
A Record of Every Plant
Living collections are distinguished from ordinary gardens by the practice of keeping and maintaining detailed records on their specimens. These accession records include information about where and when a plant was collected, which is also known as its provenance. Provenance data is critical, since without it, there is no way to trace the origins of a plant.
A great example of the value of provenance is the accession record for our great yellow pond-lily (Nuphar polysepala), which is located in the Arroyo Section. The great yellow pond-lily is not a rare species; it is found in wetlands throughout western North America and is quite common in Northern California. However, it no longer grows in Southern California. When our specimen in the Arroyo bloomed last year for the first time in years, I looked at the accession record for additional information that we could share with our visitors. What I found surprised me. Our specimen was collected in 1956 from Santa Barbara County from a place that was once a wetland but is now a golf course. Now that its habitat is gone, this plant is no longer found in the wild there — or in other places it historically existed in Santa Barbara and San Luis Obispo counties. Our specimen, therefore, represents a part of the genetic diversity of this species that would have otherwise been lost. It may have a part to play in helping with restoration efforts someday in the future, but in the meantime, it will be cared for here at the Garden to ensure its continued existence (figure 1).
In addition to harboring genetic diversity, living collections are used in a variety of ways. Researchers have used the plants in our Living Collection for projects on pollination biology, documenting hidden patterns of UV colors on flowers (figure 2), understanding gall ecology, measuring live fuel moisture to learn more about how fires spread, and more. Living collections are excellent tools for research since they can house a broad array of species in a relatively small space. Plants in a collection also respond to stimuli from their environment in ways similar to how they would in the wild.
Conserving California’s Biodiversity
We have been keeping accession records of our wild collected plants for nearly 100 years. The Garden was founded by people who understood the value of California’s native plants and habitats. Living collections with accurate provenance data such as ours are vital tools in the fight to counter the biodiversity crisis. According to Kew’s Plant Assessment Unit of global plant diversity, two in five plants globally are threatened with extinction in their native habitats. Critically, the areas with the most threatened plants are also areas with the highest biodiversity (places like California) since there are simply more unique species to lose. To help address this dramatic potential loss, the Global Strategy for Plant Conservation recommends that threatened plant species should be preserved in “ex situ” collections or collections outside of their native habitats. These ex situ collections are generally seed banks and living collections like the ones we have here at the Garden.
One rare species in our Living Collection that illustrates this is Franciscan manzanita (Arctostaphylos franciscana), a manzanita that is now extinct in the wild. This species once grew on a few outcrops of serpentine rock around San Francisco, including the Laurel Hill Cemetery where the species was first described. As the city expanded, these rugged spaces were bulldozed, taking the Franciscan manzanita with them. Fortunately, some cuttings were rescued before the species was totally eliminated, and these were sent away to botanic gardens for safekeeping. One of our accessions of this plant dates to 1938 where it was collected from Laurel Hill Cemetery by Lester Rowntree. Rowntree was a pioneering California field botanist and horticulturalist who spent months-long stretches camping and living among native plants throughout the state. Our specimen represents a piece of genetic diversity that would have been completely lost without the living collections of botanic gardens. Over the years, we have propagated cuttings from this plant for safekeeping, and it now grows in many locations throughout the Garden.
The Islands of the Californias
Our proximity to the biodiverse and beautiful California Channel Islands has inspired researchers and horticulturists here at the Garden for decades. Our Living Collection now contains 57 species found only on the Channel Islands. Many of these endemic species were once highly threatened by the introduction of grazing animals like cattle, elk, and sheep, putting them at risk of extinction. In fact, some of our specimens were collected from species with only a handful of plants left in the wild, such as the island barberry (Berberis pinnata ssp. insularis). Island barberry historically grew on a few of the Channel Islands, but the population has been reduced to a handful of individuals on Santa Cruz Island. This plant grows in shady riparian habitats, which were severely degraded by erosion caused by feral pigs and other grazing animals. By the time the last of these animals were removed in 1984 only a handful of island barberry plants remained. Even worse, these plants were separated from each other and growing on different parts of the island. This isolation appears to have made it difficult for them to reproduce since opportunities for cross-pollination are limited, and they produce little viable seed.
Cuttings from a large island barberry plant on Santa Cruz were brought into cultivation at the Garden in 1958. Plants grown from this specimen have been thriving here since. Recently, scientists at the Garden have begun researching pollination in this species using our specimen from 1958, hoping to help explain the low seed viability of this species in the wild (figure 3).
Our Collection Is Always Growing
This year, we added new specimens of the federally endangered Santa Cruz Island bush mallow (Malacothamnus fasciculatus var. nesioticus) to the Garden’s Living Collection. Bush mallows thrive in open spaces with lots of room to spread, but on Santa Cruz Island their habitat was destroyed by introduced herbivores, which had also helped the spread of invasive plants such as fennel (Foeniculum vulgare). This left only a small handful of plants in the wild. Heather Schneider, Ph.D., the Garden’s rare plant biologist, along with other staff from our Rare Plant Conservation Team collected cuttings from two previously uncollected populations on Santa Cruz Island. The goals of the project were to install these plants into our Living Collection to safeguard them from further decline and to produce material for future restoration on Santa Cruz Island. This fall our conservation and horticulture staff worked together to plant this species into areas of the Garden where they can thrive. We also paid close attention to where we added these plants since they tend to spread very far and wide — we needed to be sure that they would not grow near the other closely related bush mallow species (Malacothamnus spp.) in our Collection. Our goal is to preserve the genetic integrity of Santa Cruz Island bush mallow. Once these plants are large enough to take cuttings, we will share plants with other botanic gardens so that this species can be preserved in more ex situ conservation collections (figure 4).
Preserving Native Traditions
Our Living Collection also offers the original stewards of local lands access to native plants important to their traditions. Members of the Barbareño Band of Chumash Indians have utilized plants in the collection that they may not be able to attain freely from wild places, such as Baltic rush (Juncus balticus), white sage (Salvia apiana), Santa Cruz Island ironwood (Lyonothamnus floribundus ssp. apleniifolius), and dogbane (Apocynum cannabinum).
Building Connection With Visitors
Finally, these plants have incredible value as ambassadors of their species. When people see plants at the Garden they have an opportunity to learn more and to make a connection with a plant that they may never see in the wild. Seeing a photo of coast redwood (Sequoia sempervirens) and standing among them are two utterly different experiences. The Living Collection has been fostering these kinds of connections with California’s native plants for nearly a century now, along with providing a platform for research and conservation. As the curator of this wonderful Living Collection, I look forward to seeing the impact our Garden will have over the next century.
