The Galapagos Islands are world-famous for the large number of endemic species found only there. This applies not only to the fauna, but also to the flora of the archipelago, which has fortunately remained virtually intact. Only three endemic plant species are currently considered extinct.
But the islands' flora is also under threat. Invasive species, changes in land use, and climate change mean that more than half of the Galapagos' endemic plant species are now considered endangered. Some of these plants are even listed in the Red Book of Galapagos Endemic Plants as threatened with extinction.
Many of these plants are pioneers and are therefore a fundamental element of the Galapagos archipelago today. It is their presence that has allowed life to continue on the volcanic islands. They provide shelter, diverse habitats, and food through flowers that attract insects, fruits, or the plant itself. These ecosystem services have played a fundamental role in the evolution of the islands into the paradises we've been fortunate enough to experience.
Because of the close relationship between flora and fauna, the loss of certain plant species in this specialized ecosystem can have far-reaching consequences. Tree scales, an important habitat for many small songbird species, are a case in point. They disappeared after the introduction of blackberries (as we reported in the fall of 2022).
To combat the loss of biodiversity, the "Galápagos Verde 2050" project has begun to cultivate endangered plant species and replant them in their natural habitat. These include the following four species Galvezia leucantha subsp. leucantha, Lecocarpus lecocarpoides, Scalesia retroflexa and Scalesia affinis.
It sounds easier than it is
For most of us, growing a plant seems trivial: just put the seed in the ground, give it enough light, water and heat, and wait. But it's not so easy for the archipelago's highly specialized plants. Either because there aren't enough seeds, or because the seeds germinate only on special carriers, and then poorly or not at all. Similarly, young plants often have very specific needs that researchers have to discover through various, often unsuccessful, experiments.
Plants successfully grown in the laboratory are then replanted in their original habitat. But even that requires planning. Water is not available everywhere in the archipelago. However, a plant that grows under the protection of humans is used to receiving water on a regular basis. Long-term irrigation is therefore essential, even in the wild. The plants are therefore planted in biodegradable containers with water reservoirs or with hydrogel, a water-retaining material mixed with soil. It is also important to protect the plants from predators with wire mesh or fencing.
First breeding successes
Galvezia leucantha subspecies leucantha is an endemic subspecies of wolf's mouth. Introduced goats and rats have drastically reduced plant populations. By August 2017, only four of these plants remained on Isabela Island. By the end of 2022, researchers were able to grow 24 healthy Galvezia leucantha plants from the seeds of the five remaining plants and replant them in their natural habitat on Isabela. The problem was that many of the seeds from the last five plants failed to germinate.
Leocarpus leocarpoides is an endemic plant of the Asteraceae family found on the island of Española. It used to be found in Punta Manzanillo. However, it has not been seen since 2014. It is feared to be extinct. Leocarpus leocarpoides had also fallen victim to the voracity of the introduced goats. Despite the eradication of the goats on Española, the plant populations had not recovered. That's why we started growing seedlings from seeds preserved in the Charles Darwin Station's herbarium. The new plants have already produced over 6,000 seeds, which should make it possible to replant Leocarpus leocarpoides in Punta Manzanillo.
Scalesia
Like Galvezia leucantha subsp. leucantha, the plants endemic to the Galapagos Islands belong to the Asteraceae family, which also includes daisies, marigolds, chamomile, and various salad plants. Because of their adaptation to the different habitats of the Galapagos, Scalesia are also known as "Darwin's finches of the plant world". There are 15 species of shrub or tree Scalesia in the archipelago. Scalesia retroflexa is found only on the island of Santa Cruz and is threatened with extinction. Currently, only 23 of these plants have been found on the island. Fences have been erected around these plants to protect them from animal predation.
Scalesia affinis is found on the eastern and central islands of the archipelago, with a massive decline in populations on Santa Cruz and Floreana. In this context, the significant growth of Puerto Ayora on Santa Cruz Island has largely contributed to the loss of Scalesia affinis. Reproduction of these plants is difficult due to the limited germination capacity of their seeds. To date, more than 400 of these plants have been planted on Santa Cruz, representing 45% of the total population of this species of Scalesia on the island.
You can help
Much research is needed to extend these initial successes to other endangered endemic plants of the archipelago, and to ensure the long-term biodiversity of the Galapagos. Both in the laboratory and in natural habitats. To achieve this, it is not enough to have complete long-term seed banks, but it is also important to discover how to ensure the growth and survival of young plants and to develop sustainable cultivation methods.
The extinction of a species is final and often causes damage and problems in an ecosystem that are only realized in hindsight. Every species has a role to play in its habitat. And it can't just be replaced by another species.
Help us preserve the unique biodiversity of the Galapagos flora.