Species that Indicate an Ecosystem's Health

Actualizado: 2 ene

Indicator species are those whose presence or absence speak of the health of an ecosystem: they are the basis for ecological restoration in deforested areas because they show the way forward.

However, restoration and reforestation are not simple tasks; it's not just a matter of planting many trees: there are many factors to consider.

Some species need a lot of light, while others need shade; some require very moist —even flooded— soil, while others need dry soil; some tolerate growing very close together, while others need more space; some are naturally very resistant to pests, while others require a lot of attention and care.

In addition, it's necessary to study and analyze why each species should or should not be planted in any given deforested area, since each one has a different and specific function in the ecosystem’s balance.

The species that we are featuring in this article are particularly important in the tropical rainforest, as their presence lets us know that the forest is healthy.

Finally, when reforesting, people cannot be left out of the equation, as we are the ones who have indiscriminately cut down trees.

Community members must be actively involved in the reforestation process and must be fully convinced of how important it is to replant the indicator species in the forest.

If the local communities are not included and recognized in this process, not only will these species be lost, but also many others that depend on these, as well as part of the ancestral culture of the indigenous people.

The community of Mushullakta, in the province of Napo, where we have begun to restore the ecosystem, is right next to an old-growth forest; the indicator species that will guide the restoration process grow there.

According to Dr. Selene Escobar and her team of scientists, some of the indicator species are ‘copal’, dragon's blood, cedar, balsa tree, and ‘mascarey’. In addition to being keystone species for the environment, they are also of ancestral importance for the local Kichwa culture.

The Copal Tree

The 'copal' tree (Dacryodes olivifera) has been extensively logged in the Amazon rainforest, because its wood has been used in the construction and furniture industry.

However, its traditional uses are different. A few insect species make incisions in the trunk to lay their larvae; to 'defend' itself, the tree releases a resin, with which the larvae is covered; as they grow, the tree continues to release resin.

This process continues until a ball of resin about two or three centimeters in diameter is formed, after about four years.

At this point, the resin can be harvested; traditionally, the Kichwas used it to heal wounds and as a light source.

Nowadays, it's also used to make incense and, in general, for spiritual and religious purposes.

Resin from the copal tree

Dragon's blood from the Croton Tree

Dragon's blood is a red latex extracted from the croton tree (Croton lechleri). It can grow to be up to 25 meters high, and its trunk can be up to 40 to 50 cm wide.

Among the Kichwa people, it's known as 'yawar wiki' (yawar = blood, wiki = tear, that is, tear of blood), and has been traditionally used by the indigenous people of the Amazon to cure coughs, colds, lung problems, diarrhea, stomach ulcers and wounds.

There are two harvesting methods: the first consists of extracting all the latex and then cutting down the tree; the second consists of bleeding the tree constantly, (similar to the process for extracting rubber).

Due to the extensive use of the first method, this tree is at risk of extinction.

From left to right: latex extraction process; dragon's blood oil and resin;

drop of dragon's blood on the bark of a croton tree

The Cedar Tree

The cedar tree (Cedrela odorata) can grow to be up to 30 to 40 meters high. It has a very strong and characteristic aroma.

Since colonial times, it has been widely cut down due to its commercially valuable timber, which has been used to make canoes, furniture, handicrafts, musical instruments, among others.

Traditionally, indigenous people have used the bark as an astringent tonic and for bringing down fevers; the leaves also have medicinal uses.

It's considered a vulnerable and protected species in Ecuador; however, it continues to be illegally traded.

From left to right: Omar, one of our restorers, is collecting cedar seeds; in the second photo, you can see that the seeds have begun to sprout in the fertile soil of his restored forest.