Catalina Mahogany :: Cercocarpus traskiae

Bad at Goodbyes :: Episode 030

On today’s show we learn about the Catalina Mahogany, a critically endangered woody flowering plant native to Santa Catalina Island, near the western Northern American coast of southern California, United States.

• (00:05) Intro
• (02:05) Species Information
• (21:26) Citations
• (24:17) Music
• (33:54) Pledge

If you’d like to learn more about conserving and protecting the Catalina Mahogany, visit the Catalina Island Conservancy at https://catalinaconservancy.org/.  

Research for today’s show was compiled from:

• California Department of Fish and Wildlife – https://wildlife.ca.gov/Conservation/Plants/Endangered/Cercocarpus-traskiae 
• California Native Plants Society – https://calscape.org/Cercocarpus-traskiae-(Catalina-Island-Mountain-Mahogany)
• Catalina Island Conservancy – https://catalinaconservancy.org/stories/catalina-rare-plant-micropropagation/ 
• Center for Plant Conservation – https://saveplants.org/plant-profile/872/Cercocarpus-traskiae/Santa-Catalina-Mountain-mahogany/
• “Catalina Island Mountain Mahogany 5-year Review” US Fish and Wildlife Service. June 22, 2021 – https://www.fws.gov/node/263226 
• IUCN — https://www.iucnredlist.org/species/37562/183451015 
• “Rarest of trees exists in one place: Catalina”. Jessica Boudevin. The Catalina Islander. September 5, 2020 – https://thecatalinaislander.com/rarest-of-trees-exists-in-one-place-catalina/ 
• “VARIATION IN CERCOCARPUS IN SOUTHERN CALIFORNIA”. SEARCY, K.B. (1969), New Phytologist vol. 68: 829-839. – https://doi.org/10.1111/j.1469-8137.1969.tb06482.x 
• Wikipedia – https://en.wikipedia.org/wiki/Cercocarpus_traskiae

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A note on accuracy: I strive for it! These episodes are well-researched and built from scholarly sources, hoping to provide an informed and accurate portrait of these species. That said, I’m an ambient musician! I am not an academic and have limited scientific background. I may get things wrong! If you are using this podcast for scholarship of any kind, please see the cited sources and double-check all information.

Welcome to Bad at Goodbyes.

On today’s show we consider the Catalina Mahogany

The Catalina Mahogany is a critically endangered woody flowering plant native to Santa Catalina Island, near the western Northern American coast of southern California, United States.

The Catalina Mahogany, sometimes also called the Santa Catalina Island Mountain Mahogany typically grows to a height between 20-30 ft. Its trunk is slender and forking, usually less than 1 foot in diameter, and covered in a smooth, gray, red-ish brown, like mahogany-colored bark. It should be noted though that the Catalina Mahogany is not in fact a mahogany at all, it is in the Rose family.

The branches are spreading and often form a dense, rounded crown of evergreen leaves. The leaves are oval-shaped with serrated edges and have a leathery texture. They are a dark green color on the upper surface and the underside is covered in dense, woolly hairs, giving them a whitish or grayish appearance.

The flowers of the Catalina Mahogany are small and totally lack petals. The creamy white flowers have numerous stamens, the male reproductive organ, with prominent yellow anthers, anthers are the pollen producing bits at the tip of stamen giving the flower an appearance a bit like a tangled poof. Um, they’re cool looking and strange and quite beautiful.

The flowers present in clusters and typically bloom between March and May, though the plant does not flower every year.

Catalina Mahogany are wind-pollinated. The lack of flower petals is an adaptation thought to aid in wind dispersal. Following successful pollination, the flowers develop into small, dry green-ish brown fruits, holding a single seed, with a persistent style. The style is the elongated part of the pistil, the female reproductive organ, and in the Catalina Mahogany the style remains attached to the fruit, it’s persistent, it’s a roughly 3 inch, feathery tail, which aids in wind dispersal.

The Catalina Mahogany is slow-growing and it takes several years for new seedlings to reach reproductive maturity. It can live for decades, some estimates suggest even up to 100 years.

The Catalina Mahogany is native to Santa Catalina Island, part of the Channel Islands archipelago, roughly 25 miles off the coast of Southern California, about 50 miles south of Los Angeles.

The island is only 76 square miles with nearly 90% of its land protected for conservation.

The current population of the Catalina Mahogany in the wild is a small group within a single dry arroyo called Wild Boar Gully. An arroyo is a steep-sided canyon formed by the historic action of fast-flowing water that is generally dry, but might temporarily fill after ample rain. Wild Boar Gully is steep and rocky with slopes strewn with boulders and outcrops and covered in coastal sage scrub. The soil is thin, and nutrient-poor.

Santa Catalina has hot, dry summers and mild, wet winters. Summer temperatures crest into the 90s° F, winter temps rarely reach freezing. Rainfall is spare, averaging around 12 inches per year, with most of it falling between November and April.

Though this climate sounds challenging, Santa Catalina hosts a richness of life, a special place with a specific evolutionary history. The following list is all species native solely to the island. The Catalina Mahogany shares its island home with:

Catalina Island Shrew, Santa Catalina Island Manzanita, Catalina Hutton’s Vireo, Catalina Island Fox, Catalina Island Harvest Mouse, Santa Catalina Island Buckwheat, Catalina Walking Stick, Jerusalem Cricket, Santa Catalina Island Popcorn Flower, Catalina Island Dudleya, Bewick’s Wren, Santa Catalina Island Ironwood, Trask’s Yerba Santa, Catalina Orange-Tip Butterfly, Catalina Mountain Snail, Santa Catalina Island Bedstraw, Catalina Island Deer Mouse, Darkling Beetle, Catalina California Quail, Santa Catalina Island Bush-Mallow, Catalina Two Striped Garter Snake, Catalina Ground Squirrel and many many more.

————

In the dream,

I am dressed, well, like a widow, like a Victorian widow. All in black with my face cover, and in the dream, and sometimes too in waking life, this feels right. To hold grief present, but internal, close and intimate. But this next part too feels right. To unveil, to unmask, to open the living face to the world, to broadcast the keening, the furious mourning, to shamelessly present our rage and sadnesses, to speak them, as elegy and incantation. This in the dream, and perhaps too in life, is a beginning, it is in naming loss, that we might begin to imagine repair.

In the dream.

————

The primary historic threat to the Catalina Mahogany was from non-native human-introduced grazing mammals like goat, pig, and mule deer. Today, substantive conservation activity has led to the complete removal of the feral goat and pig populations from the island and the tree's remaining grove is protected from the mule deer by fencing.

And so today the plant’s primary threats are reproductive: low seed viability, very low seedling success, and risk of genetic swamping. Decades of overgrazing resulted in a population that is not only small, it is old. And researchers have found that though the plant is still pollinating, fruiting, and producing seeds, many of the seeds are not viable. Relatedly many of the seeds that do germinate and grow into young seedlings and saplings are not reaching reproductive maturity. We are not sure why this is the case.

Though it may be related to genetic swamping. So let’s unpack genetic swamping. Two closely related plants can pollinate each other, mixing their DNA in the produced seeds. Often this results in not viable seeds, when the two species DNA does not combine successfully. Sometimes though, it works, and the result is a hybrid: Loganberry, Grapefruit, Sweet Corn. Hybrids are a totally normal part of the evolutionary process and over time with continued successful cross-breeding can even become distinct enough to be considered their own new species. Under normal circumstances we see mostly regular reproduction, intraspecies reproduction with very occasional hybridization.

But with the Catalina Mahogany, we’re seeing genetic swamping. The small grove of Catalina Mahogany is surrounded by many many Birch Leaf Mountain Mahogany plants. So many that during the flowering season, the Catalina Mahogany is being overwhelmed by the pollen of the Birch Leaf Mahogany. This is preventing the catalina from reproducing within its own species and resulting in these relatively low success hybrid seed and seedlings.

Conservationists have recently taken the extensive step of moving many of the Birch Leaf Mahogany away from the Catalina Mahogany, in hopes of relieving some of the pollen pressure. It is not yet clear whether that has worked.

Scientists have also found that conventional conservation strategies, like artificial fertilization, transplanting wild seedlings into a protected greenhouse, or cloning the plant by taking cuttings have had limited success.

So they’re working on a really innovative way to help conserve and eventually re-introduce the Catalina Mahogany, called Micropropagation, or Plant Tissue Culture.

Kevin Alison, the rare plant ecologist at the Catalina Island Conservancy is leading and refining this process. He takes very very small cuttings of the wild plant, sterilizes them, places them in test tubes, in a like an idealize gel mix of all the plant nutrients, food, hormones, all the things the plant will need for healthy growth and of course, in the testtube in the lab, the new clone is totally protected from stressors like weather, bacteria, insect and grazers. The result is a small, like pure living specimen, that can then itself be cut and re-propagated. This is one of the big advantages of the process. Many many new clones, that we are confident are viable, can be produced from a small initial cutting, which obviously minimizes harm to the original wild plants.

Alison’s plan is to re-introduce these clones to a different part of the island far from the Birch Leaf Mahogany, so the Catalina Mahogany might begin reproducing normally again.

These micropropagated offspring are also a kind of safeguard, an archive of genetic material. Conventional seedbanking is one way we do this, though time affects seed viability, making for an imperfect archive. Alison’s micropropagation presents the possibility of safe cryogenic freezing of the specimen,which is a potentially more stable genetic repository. This is cool, really pioneering stuff, happening in only a few places right now, including the San Diego Zoo which is developing what they call a “Frozen Zoo”, a kind of cold storage of living genetic materials.

In the case of the Catalina Mahogany, next steps are in process, a kind of preparation for their return to the wild Alison calls it hardening off, acclimatizing. The micropropagated seedlings are slowly weaned from their nutrient gel and transplanted into a greenhouse, then moved to an outdoor protected growing yard, then eventually planted in an appropriate habitat on the island, a site with like less human-caused stressors, and with the hope that will begin reproduce in the wild again.

Information for today’s show about the Catalina Mahogany was compiled from:

California Department of Fish and Wildlife – https://wildlife.ca.gov/Conservation/Plants/Endangered/Cercocarpus-traskiae

California Native Plants Society – https://calscape.org/Cercocarpus-traskiae-(Catalina-Island-Mountain-Mahogany)

Catalina Island Conservancy – https://catalinaconservancy.org/stories/catalina-rare-plant-micropropagation/

Center for Plant Conservation – https://saveplants.org/plant-profile/872/Cercocarpus-traskiae/Santa-Catalina-Mountain-mahogany/

IUCN — https://www.iucnredlist.org/species/37562/183451015

“VARIATION IN CERCOCARPUS IN SOUTHERN CALIFORNIA”. SEARCY, K.B. (1969), New Phytologist vol. 68: 829-839. – https://doi.org/10.1111/j.1469-8137.1969.tb06482.x

Wikipedia – https://en.wikipedia.org/wiki/Cercocarpus_traskiae

If you’d like to learn more about conserving and protecting the Catalina Mahogany, visit the Catalina Island Conservancy at https://catalinaconservancy.org/

I honor the lifeforce of the Catalina Mahogany. I will commit its name to my record. I am grateful to have shared time on our planet with this being. I lament the ways in which I and my species have harmed and diminished this species. I grieve.

And so, in the name of the Catalina Mahogany I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of plant or animal kin or their habitat, by individuals, corporations, and governments.

I pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.