Bad at Goodbyes

Rough Transcript

Intro 00:05

Welcome to Bad at Goodbyes.

On today’s show we consider the Caroline’s Pink.

Species Information 02:05

The Caroline’s Pink is a critically endangered flowering herbaceous perennial plant native to North Caicos and Middle Caicos, islands in the Turks and Caicos archipelago, a British Overseas Territory in the Caribbean region, though in the Atlantic Ocean. Its scientific name is Stenandrium carolinae and it was first described in 1960.

 

Description

Caroline’s Pink is small and low-growing; they are acaulescent. Meaning that they have an extremely short stem, not visible above the soil, so the leaves often lay flat against the ground. The leaves are elliptic, oval shaped, tapering at the tip and at the base where the leaf emerges from the soil. The leaves are roughly 1 inch long and half an inch wide with entire margins, that is smooth edges. Both the upper and lower surface of the leaves are covered in a dense pubescence, tiny hairs, trichomes, an adaptation to prevent water loss, in their hot windy Caribbean habitat.

 

Water loss, that is transpiration, is the evaporation of water from like the above ground parts of a plant, generally the leaves and stem. This is a key mechanism in the plant’s internal nutrient transport system, kind of like its circulatory system. So, the plant’s leaves release water vapor from tiny pores called stomata. That release creates an internal suction pressure which draws water and nutrients up through the plant, from the roots, to the leaves.

 

This process, the transpiration rate, is partially regulated by the humidity at the leaves’ surface. Humidity describes how dense the atmosphere is with water, how much water vapor is in the air. So, the leaves release water vapor, from the stomata, the tiny pores, some evaporates and some accumulates in what’s called a boundary layer, a thin layer of high humidity at the leaf’s surface. Water vapor evaporating vs accumulating affects the plants transpiration rate.

 

So, on a hot windy day, the heat will increase evaporation, and the wind will interrupt the leaves’ boundary layer, dissipating the humid air on its surface, both of which significantly increase the rate of transpiration. The rate of water loss.

 

And so the Caroline’s Pink leaves are covered in these tiny hairs, these trichomes that serve to help block the wind and sun. The hairs help to hold in water vapor, trapping it against the leaves’ surface and they also reflect sunlight, reducing evaporation, decreasing the rate of the transpiration, preventing water loss.

 

So Caroline’s Pink is adapted to its dry tropical habitat, the low-growing form, the tricomes. But when they flower they grow a relatively tall flower stalk, up to 5 inches in height to rise above the undergrowth, to be conspicuous to potential pollinators. At the top of the stalk grows an inflorescence, a flower cluster of violetty-pink 5 petaled blooms.

 

Reproduction

The Caroline’s Pink is a perennial, meaning they live for multiple years, flowering and reproducing multiple times. They generally bloom in the spring. And are likely pollinated by bee and butterfly.

 

Once pollinated, they produce small dry dehiscent capsular fruit. So, a hardened dry fruit, less than a half inch in diameter, a capsule that contains the seeds, which later splits open to release them. The seeds are dispersed by ballochory, expelled by force, like “shot” away from the plant. So the capsule fruit splits open and the seeds are flung away from the parent plant, distributed so the new seedlings are not in direct competition with the parent for soil nutrients.

 

Habitat

This is a vital adaptation to the Caroline’s Pink’s relatively resource poor native habitat. The Caroline’s Pink is native to two islands in the Turks and Caicos archipelago, North Caicos and Middle Caicos. Located in the Caribbean region, in the Atlantic Ocean, roughly equidistant from both mainland North and South America, roughly 600 miles from each.

 

These islands are small, together only about 100 sq miles. The Caroline’s Pink is found just inland from the coast in a pine rockland ecosystem, a rocky landscape of weathered, crevassed, and jagged limestone, with thin soils, and an open canopy dominated by Caicos Pine with an understory of sparse low growth fire-adapted vegetation. 

 

Historically, this area would see wildfire, ignited by lightning, every 3-10 years. These low-intensity burns clear out undergrowth and consume fallen pine needles returning nutrients to the soil. Fire adapted conifers, like the Caicos Pine would survive. As would low-growing acaulescent perennials, like our Caroline’s Pink, whose root systems survive underground, regrowing in newly resourced soils, in a landscape cleared of competition for light and nutrients.

 

The Caroline’s Pink’s range in these pineyards, is very small, only about 5 square miles total.

 

This is a tropical savanna climate with summer high temperatures that can reach into the mid-90s°F; winter lows only dipping into the 60s°F. Annual rainfall is low, averaging roughly 30 inches per year and is highly seasonal, most of which falls between June and November.

 

The Caroline’s Pink shares its island home with:

Caicos Skink, Caicos Barking Gecko, Turks and Caicos Rock Iguana, West Indian Osprey, Turks and Caicos Curly-Tail Lizard, Bahama Woodstar Hummingbird, Buffy Flower Bat, Caicos Encyclia Orchid, Caicos Pygmy Boa, Turks Island Leaf Butterfly, North Caicos Milkweed Vine, Thick-Billed Vireo, Capillary Buttonbush, Hatpin Sedge, Britton’s Buttonbush, Greater Antillean Bullfinch, Drury’s Hairstreak Butterfly, Blue Land Crab, Turks and Caicos Heather, Caicos Pine, and many, many more.

In the Dream

————

In the dream,

 

To live on the outskirts of paradise,

In the wind-swept bits, in the forgotten bits,

In the parched cracks between glittering coasts,

 

Among the towering pines,

Aching for fire, aching for rain,

Peeking out from low cover

to blossom.

 

A tiny cluster of pink

On the dusty backroad to Elysium.

 

In the dream.

————

Threats

Historically, human activity has resulted in significant habitat destruction on North Caicos and Middle Caicos. Land cleared for construction, development, and infrastructure expansion, generally to cater to tourism, has profoundly reduced the available habitat for the Caroline’s Pink.

 

Human intervention has also disrupted the pineyards natural fire cycles, resulting in a buildup of overgrowth, which compete for light and nutrients.

 

But today, the most pressing threat to the Caroline’s Pink is in fact a threat to the Caicos Pine. The human introduced invasive Pine Tortoise Scale insect has devastated the Caicos Pine. First recorded in 2005, the scale insect has since wiped out 95 percent of the Caicos Pine population, a catastrophic loss in general, and a catastrophic loss of a keystone species in the Caroline’s Pink’s habitat. As the scale insect feeds on the pine it excretes a sticky substance that fosters the growth of black sooty mold. This mold covers the leaves of understory plants, including the Caroline’s Pink, blocking sunlight, impeding photosynthesis. Additionally, as the Caicos Pines die, the ecosystem is shifting from an open savannah to a more densely foliaged overstory, also shading out low growing vegetation. The conservation and protection of the Caicos Pine is likely critical to the longterm survival of the Caroline’s Pink.

 

Additionally human induced climate change, global warming due to persistent over-reliance on fossil fuel burning, is an oncoming threat. Areas of the Caroline’s Pink’s range are only a few feet above sea level. And so, as a warmer climate results in melting icecaps, our oceans rise. The coasts and immediate inland, of low lying islands, like North Caicos and Middle Caicos, are threatened by sea-level rise, initially by saltwater intrusion, which would kill freshwater vegetation.

 

Relatedly, the Caribbean region is seeing an increase in the frequency and severity of extreme weather, again the result of human-induced climate change, specifically hurricanes. More intense hurricanes means larger storm surges, which inundate the low elevation pineyards with saltwater, again causing mortality to both the pines and to understory vegetation like the Caroline’s Pink.

 

Conservation

Fortunately, the Caroline’s Pink is legally protected in Turks and Caicos, law which now requires consideration of the species prior to new construction and development. 

 

Their seeds have been collected and stored safely off-site at the Kew Royal Botanic Gardens’ Millennium Seed Bank.

 

And conservation interest in the Caicos Pine has brought attention to this habitat which will likely have positive repercussions for the Caroline’s Pink.

 

Nevertheless the Caroline’s Pink has been considered critically endangered on the IUCN Red List since 2012 and their population is currently in decline.

 

Our most recent counts estimate that less than 975 Caroline’s Pink remain in the wild.

Citations 20:16

Information for today’s show about the Caroline’s Pink was compiled from:

 

Earle-Mundil, H., Manco, B., Hamilton, M. & Clubbe, C. 2012. Stenandrium carolinae. The IUCN Red List of Threatened Species 2012: e.T16726348A16727210. –  https://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T16726348A16727210.en

 

Franck, Alan R., and Thomas F. Daniel. 2015. “Taxonomic and Nomenclatural Notes on Six Genera of Acanthaceae in the West Indies.” Proceedings of the California Academy of Sciences, Series 4, 62 (10): 309–29. – https://www.researchgate.net/publication/285235613_Taxonomic_and_Nomenclatural_Notes_on_Six_Genera_of_Acanthaceae_in_the_West_Indies

 

Institute for Regional Conservation. n.d. “Stenandrium carolinae.” Plants of the Bahama Archipelago. – https://regionalconservation.org/ircs/database/plants/PlantPageBAH.asp?TXCODE=Stencaro

 

Leonard, Emery C. 1960. “Acanthaceae Americanae Novae vel Criticae.” Wrightia 2: 75–82. – https://www.biodiversitylibrary.org/page/766031

 

Long,  Robert W. 1970. “The Genera of Acanthaceae in the Southeastern United States.” Journal of the Arnold Arboretum 51 (3): 257—309. – https://doi.org/10.5962/bhl.part.7043.

 

May, Christopher, Samuel Pike, Katie Medcalf, B. Naqqi Manco, Dodly Prosper, and Junel Blaise. 2024. “Conservation and Resilience.” Times of the Islands, Spring 2024. – https://www.timespub.tc/2024/03/conservation-and-resilience/

 

Pelembe, T., and G. Cooper, eds. UK Overseas Territories and Crown Dependencies: 2011 Biodiversity Snapshot. Peterborough, UK: Joint Nature Conservation Committee, 2011. – https://jncc.gov.uk/resources/e5d8c245-e94d-4043-b1b8-f353c27cd9b4#ot-biodiversity2011-turks-caicos-appendices.pdf 

 

Pienkowski, Mike, ed. 2002. Plan for Biodiversity Management and Sustainable Development around Turks & Caicos Ramsar Site. Version 1.00. Turks & Caicos National Trust and UK Overseas Territories Conservation Forum. – https://www.ukotcf.org.uk/wp-content/uploads/2020/04/TCIRamsarSiteManPlan.pdf

 

UK Overseas Territories Conservation Forum. n.d. “Turks and Caicos Islands.” – https://www.ukotcf.org.uk/wider-caribbean/turks-and-caicos-islands/

 

Sanchez, Michele Dani, Bryan Naqqi Manco, Junel Blaise, Marcella Corcoran, Martin Allen Hamilton. 2019. “Conserving and Restoring the Caicos Pine Forests: The First Decade.” Plant Diversity 41 (2): 75–83. https://doi.org/10.1016/j.pld.2018.05.002

 

For more information about conservation on the Turks and Caicos islands please see the UK Overseas Territories Conservation Forum at https://www.ukotcf.org.

Music 22:18

Pledge 28:28

I honor the lifeforce of the Caroline’s Pink. 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 Caroline’s Pink 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 and animal kin and their habitat, by individuals, corporations, and governments.

 

I forever 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.