Searching for Extinction in Western Ecuador

Searching for Extinction in Western Ecuador

Words and photos by Riley Fortier

November 12, 2022 - Almost exactly one year after the rediscovery

Hidden for almost 40 years, a mysterious little herb made its reappearance in the dark and dense understory of an Ecuadorian cloud forest. Botanists were elated when they finally found the critically endangered plant, which had only been documented four times before. The rediscovery marked an important chapter in the story of the Centinela ridge, a site famed for its unique biodiversity and a poster child for extinction in the Anthropocene. 

The story of our plant starts nearly five decades ago, when botanists Alwyn Gentry and Calaway Dodson were drawn to an outlying ridge on the western side of the Ecuadorian Andes. The isolated ridge traps clouds and creates its own climate, producing a unique cloud forest “island” surrounded by lowlands. For these reasons, Gentry and Dodson speculated that the ridge, which they called “Centinela”, had generated a diverse assemblage of endemic species found nowhere else. After years of collecting plants, their speculations held true when they found 10% of the flora to be restricted to the small ridge. Over the following years, however, Centinela experienced massive deforestation to make way for pasture, banana, cacao, and coffee. By 1985, Gentry and Dodson were “alarmed” at the state of the ridge’s forests, knowing that the extinction of many rare and endemic species was on the horizon. This sentiment was echoed by the late E. O. Wilson who, in 1992, coined the term “Centinelan extinction” to describe species that go extinct before they can even be discovered by scientists. This idea inspired botanists in 2000 to apply a rather dramatic and bleak name to a newly described species, Gasteranthus extinctus, which was known only from Centinela. They were certain that the plant had already been driven to extinction. Not much additional work ever took place on Centinela, and it seemed as if its saga had reached an end. Its forests were gone and its unique plant species eradicated, without much hope of return. 

We thought otherwise. Our team of botanists - five from Ecuador, three from the US, and two from France - set out to see if the forests on Centinela really were lost, with a prominent goal of finding G. extinctus, a plant whose name kept us up at night. Prior to starting the expedition, our team scoured maps and satellite imagery to try and identify remnant patches of forest on Centinela. This task was easier said than done, as a matrix of Balsa (Ochroma pyramidale) and Melina (Gmelina arborea) plantations across the landscape give the illusion of good forest, but in reality, these tree farms harbor little biodiversity and have replaced what was once primary forest. Once we trained our eyes, we began to distinguish the homogenous, even canopy of tree plantations from the complex, diverse canopy of primary forest. Our efforts were fruitful when our boots hit the ground and we stepped into patches of beautiful, primary cloud forest still hanging on to Centinela. 

Our search for an “extinct” plant was successful almost immediately. G. extinctus flowers are bright orange signals begging to be seen among a sea of green, so locating the understory herb was rather straightforward once we knew what to look for. On the very first day of the search, we found the plant growing healthily in two different forest patches. On day two we found another population, and on day three, in a forest completely separated from Centinela, another population! As it turns out, G. extinctus isn’t extinct, nor is it endemic to Centinela at all. In three days, we had documented more populations of the notorious little plant than in the previous 40 years combined. Its rediscovery heralds a change in thought about Centinelan extinction and about the value of targeted, field-based searches in general. 

Was it premature to call Centinela a lost cause? We believe so. Despite previous narratives of complete deforestation on Centinela and the extirpation of many of its plant species, our searches uncovered healthy, intact forest fragments and the presence of a species presumed to be extinct. Patches of primary forest and rare plants still exist on Centinela, albeit in a tiny fraction of their former abundance. Unfortunately, it may not be long before these patches and their flora are, indeed, lost forever as deforestation continues in the region. Before this happens, it is imperative that we further explore Centinela’s remaining forest fragments and protect what is left. The sun hasn’t completely set on Centinela, and now is the time to conserve the imperiled plants and animals that call this unique place home. 

Conserving the forests of Centinela cannot be done without the collaboration and involvement of local landowners. Conservation can only succeed when every actor is on board. After all, the residents of Centinela know the region’s history better than anyone, know who owns which patches of forests, and have tended to the land for years. We wouldn’t have been able to access the remaining patches of forest without the help of many locals. For this reason, they are in our gratitude. The best thing we can do now is to convince these landowners to keep remaining forest patches intact and push for their formal protection. Maybe someday, we can appreciate the unique beauty of these forests like Gentry and Dodson did decades ago, and like everybody before them.

Read about our discovery in the published paper: 

Pitman NCA, White DM, Guevara Andino JE, Couvreur TLP, Fortier RP, Zapata JN, Cornejo X, Clark JL, Feeley KJ, Johnston MK, Lozinguez A, Rivas-Torres G (2022) Rediscovery of Gasteranthus extinctus L.E.Skog & L.P.Kvist (Gesneriaceae) at multiple sites in western Ecuador. PhytoKeys 194: 33–46. https://doi.org/10.3897/phytokeys.194.79638

Explore more Centinelan discoveries and conservation initiatives at the Centinela website here: https://sites.google.com/view/vivacentinela/home

Some important notes about Centinela:

It’s worth mentioning that of the many plant species believed to be endemic to Centinela, the vast majority have been recorded elsewhere through the years. In other words, endemic plants aren’t nearly as abundant on Centinela than previously thought. This is not to say that Centinela isn’t special, but instead, that we have so much more to learn about its flora. In fact, we have a lot more to learn about South American flora in general.

The name “Centinela” was used by Gentry and Dodson to describe the prominent ridge discussed in this blog post. However, the name is hardly used by locals, except to describe a town named “Centinela del Pichincha” which was probably the origin of Gentry and Dodson’s usage of the name. Locals in the region instead refer to the ridges as “Montañas de Ila”, or “Bijagual”, among other names. 

References:

Dodson, C. H., & A. H. Gentry. 1991. Biological extinction in western Ecuador. Ann. Mo. Bot. Gard. 78(2): 273–295.

Skog, L. E. & L. P. Kvist. 2000. Revision of Gasteranthus (Gesneriaceae). Syst. Bot. Monogr. 59. 118 pp.

Wilson, E. O. 1992. The diversity of life (Harvard University Press, Cambridge, MA).

Tags: botany, Centinela, conservation, endemism, Gasteranthus extinctus, habitat fragmentation