The plants need our help

The Galápagos Islands are known worldwide for the large number of endemic species that occur exclusively there.  This applies not only to the fauna, but also to the flora of the archipelago, which fortunately is still almost intact. Only three endemic plant species are currently considered extinct.  

However, the islands' flora is also under threat. Invasive species, changes in land use and climate change are contributing to the fact that more than half of the Galápagos Islands' endemic plant species are now classified as endangered. Some of these plants are even classified as endangered by the Red Book of Galápagos Endemic Plants.    

Many of the plants are pioneer plants and thus a basic building block of today's Galápagos archipelago. Only their presence has made further life on the volcanic islands possible. They offer protection, different habitats and provide food through flowers that attract insects, fruits or through the plant itself. These ecosystem services have made a fundamental contribution to the development of the islands into the paradise we have come to know.  

Because there is a close connection between flora and fauna, the loss of individual plant species in this specialized ecosystem can have far-reaching consequences.  One example of this is the tree scales, which provide an important habitat for many small songbird species. They have become extinct as a result of the introduced blackberry plants (we reported on this in the fall of 2022).  

In order to counteract the loss of biodiversity, the "Galápagos Verde 2050" project has started to cultivate plant species that are threatened with extinction and replant them in their natural habitat. These include the following four plant species: Galvezia leucantha subsp. leucantha, Lecocarpus lecocarpoides, Scalesia retroflexa and Scalesia affinis.  

For most of us, growing a plant sounds trivial; you put the seed in the soil, provide sufficient light, water and warmth and wait. But it's not quite that simple with the very specialized plants on the archipelago. It may be that there are too few seeds, that the seeds only germinate on special substrates and then poorly or not at all. The young plants also often have very specific needs, which the researchers have to find out through various, often unsuccessful experiments.  

The plants successfully grown in the laboratory are then released in their original habitat. But this also requires planning. Water is not available in sufficient quantities everywhere on the archipelago. However, a plant that grows up in human care is used to regular watering. It is therefore essential to ensure long-term irrigation in nature as well. The seedlings are therefore planted out in biodegradable containers with water tanks or using hydrogel, a water-retaining material that is mixed into the soil. It is also important to protect the plants from being eaten by animals using grids or fences.  

First successes with offspring  

Galvezia leucantha subspecies leucantha is an endemic subspecies of snapdragon. The plants were drastically reduced by introduced goats and rats. In August 2017, there were only four of these plants left on the island of Isabela. By the end of 2022, the researchers succeeded in growing 24 healthy Galvezia leucantha plants from the seeds of the remaining five plants and planting them in their natural habitat on Isabela. One problem, however, was that a large proportion of the seeds from the last five plants failed to germinate.  

Scalesia 

The plants endemic to the Galápaogos Islands, like Galvezia leucantha subsp. leucantha, belong to the Asteraceae family, which also includes daisies, marigolds, chamomile and various salad plants. Due to their adaptation to the different habitats on the Galápagos Islands, the scalesias are also known as the "Darwinian finches of the plant world". There are 15 species of shrub or tree scalesia on the archipelago. Scalesia retroflexa is found exclusively on Santa Cruz Island and is threatened with extinction. Currently, only 23 of these plants have been found on the island. Fences have therefore been erected around the plants to protect them from possible animal predation.  

Scalesia affinis can be found on the eastern and central islands of the archipelago, although the populations on Santa Cruz and Floreana are in massive decline. The considerable growth of Puerto Ayora on the island of Santa Cruz has contributed significantly to the loss of Scalesia affinis. Reproduction of the plants is difficult as their seeds only have limited germination capacity. To date, over 400 of these plants have been planted on Santa Cruz, accounting for 45 % of the total population of this Scalesia species on the island. 

A great deal of research is still needed to transfer these initial successes to other endangered endemic plants of the archipelago and thus ensure the long-term biodiversity of the Galápagos Islands.  Both in the laboratory and in the natural habitats. In the long term, this will not only require comprehensive seed banks. It is also important to find out how the growth and survival chances of the seedlings can be ensured and how sustainable breeding methods can be developed. 

The extinction of a species is final and often leads to damage and problems in an ecosystem that only becomes apparent in retrospect. Every species has its task in its habitat. And it cannot simply be replaced by another species.