Rewilding: what is it, what is it for and how does it work?

Let's take a look at what rewilding is and how it helps maintain the natural balance.

Human beings are increasingly consuming more and more natural resources, which translates into environmental changes at the ecosystemic and global level. The damage we are causing to the planet is quantifiable, since according to the International Union for Conservation of Nature (IUCN), 32,000 species of living beings are currently endangered.

The picture is not much more encouraging if we look at more specific figures. For example, scientists theorize that, as you read these lines, 150 to 200 species are becoming extinct every day. Many of them will never be discovered or classified, a disheartening reality for any biologist or nature lover.

As all this data indicates, it is time to take action. Sometimes anthropic modifications are completely irreversible and the only thing left to do is to try not to repeat such crimes against the ecosystem, but on other occasions, conservation biology has certain tools up its sleeve.

This is the case of resilvestration or rewilding, through which human beings try to give back to the environment the balance it deserves.. Here we tell you all about this concept of large-scale conservation. Stay with us, because in terms of environmental restoration, there is still a light at the end of the tunnel.

Resilviculture or rewilding: giving back to the planet what is its own

Resilviculture is defined as a concept of conservation on a large scale, aimed at restoring and protecting natural areas by reintroducing keystone species and promoting connectivity between areas degraded by human activities.

Initially, the term rewilding was coined to implement certain strategies focused on reintroducing keystone predator species into an ecosystem, thus seeking to restore the trophic balance of the ecosystem. A clear "textbook" example of this is the Yellowstone wolves, which were released in the park after the massive growth of elk that had led to the disappearance of this hunter in 1926.

The truth is that, today, restocking encompasses a much more multidisciplinary terminological umbrella. It is not only about reintroducing species, but also about restoring the ecological integrity of the environment and reducing human impact on it. on the environment. The objective is clear and concise: we seek ecological restoration to the point where the ecosystem is able to naturally self-regulate again.

The foundations of resilvesting

Resilviculture is based on the analysis and action on three essential ecosystem pillars: trophic complexity, natural disturbances and connectivity. Each of these bases is described in detail below.

1. Trophic complexity

This is the approach most similar to the original rewilding concept. Large herbivorous animals generate diverse influences on the ecosystem in which they are found, since, with their browsing activity and consumption of plants, they directly affect other taxa such as small birds, micromammals, insects and plants. Natural ecosystems are in an absolute equilibrium.The super-predators keep these large living creatures in check so that their activity does not get out of control and basically any environment becomes a wasteland.

When humans get their hands where they don't belong, this balance can be drastically upset. Whether due to lack of prey, destruction of feeding grounds or direct hunting, in many cases, these top predators and other keystone species end up suffering the effects of anthropogenic modifications, resulting in a dramatic shift in the balance of the species.This results in a drastic reduction of their population numbers and even a subsequent complete disappearance.

Trophic rewilding not only contemplates reintroducing species that were previously in the ecosystem and were key to its maintenance, but can also be addressed under a passive and preventive approach. The coexistence of humans with the species in the ecosystem can be encouraged or legislation can be passed to limit or prohibit the hunting of endangered species, and this is known as passive rewilding.

In the event that the species of interest has completely disappeared, reintroduction can be considered. reintroduction or ecological replacement (replacing one species with a more suitable (replacing a species with a more suitable species in the ecosystem that has lost its equilibrium with the same function), although the effects of the latter technique can be very dangerous in the long term. Of course, when altering ecosystems, one must be cautious, as the effects can be irreversible.

2. Natural alterations

Although it may not seem so at first glance, not all natural catastrophes are negative at the ecosystemic level. For example, the emergence of Biological pests, small-scale fires or floods produced by a normal climatic regime can promote the reconfiguration of ecosystems and their species, resulting in greater biological heterogeneity.

In anthropized environments, natural disturbances are usually suppressed or controlled in a deterministic manner, which can lead to catastrophes on a much larger scale (e.g., several small fires can prevent a massive fire from occurring in the future). This pillar of rewilding seeks to recover the stochasticity of natural events: it is not a matter of everything being controlled by humans, but of the ecosystem being self-regulating. the ecosystem to regulate itself in the most logical way possible..

3. Connectivity

Connectivity is essential between populations of living beings, because gene flow prevents the effects of genetic drift from becoming deleterious to species in nature.. Without going into genetic terms that are beyond the scope of this opportunity, we can summarize this whole process in the following concept: a new visitor to a population is a breath of fresh air, as it can bring with it new variations in its genes that will be transmitted, through reproduction, to future generations.

Unfortunately, many structures of human origin limit or directly cut off connectivity between populations. Something as simple as a road can be an impassable barrier for many living beings, preventing interaction between different populations of the same species.

This branch of rewilding tackles this problem by means of the creation of ecological corridors (structures that allow animals to move in spite of human constructions) or simply by avoiding the construction of these structures in the first place. The measures for population connectivity are multiple, but the general aim is to try to restore the gene flow that occurred naturally in the ecosystem.

Some examples

Not everything remains in theory, as resilvesting has been put into practice on multiple occasions. There are portals such as this one that collect various events in which they have tried to restore the balance of many ecosystems highly influenced by human action, either basing efforts on one of the pillars shown or using a multidisciplinary approach.

Many of these projects go beyond the reintroduction of predators. For example, in the Côa valley of northern Portugal, the reintroduction of domesticated and semi-free-ranging herbivore species is being explored in order to increase grazing activity. reintroduction of domesticated and semi-free-ranging herbivore species is being explored to increase grazing activity and thus avoid the presence of shrubs and large areas susceptible to fire. and thus avoid the presence of shrubs and large areas susceptible to fires.

Another of today's high-profile cases is the restocking of the central Apennines in Italy. In this case, the creation of the ecological corridors mentioned above is being promoted, conservation measures to increase the population numbers of the bear Ursus arctos marsican. Ursus arctos marsicanus and the promotion of ecotourism.

As we can see, not all rewilding events are based solely on introducing live specimens of keystone species: in most cases, a multidisciplinary approach is needed.

Summary

As we have mentioned in these lines, the concept of rewilding has undergone a process of evolution in recent decades, where the integration of multiple parameters is sought: restoring trophic complexity, giving way to natural disturbances and promoting population connectivity. Beyond this, it also seeks to legislate in favor of the protection of vulnerable ecosystems and their species, encourage population interest in the natural elements that surround us and promote coexistence between the environment and human activities.

Rewilding has a concrete goal: to recover as much as possible the self-regulation that once characterized the damaged ecosystem.. This is achieved through strategies that generally go far beyond the reintroduction of a predatory species. As in most cases, in the variety of tools lies the key to success.

Bibliographical references:

• Making Europe a wilder place, rewildingeurope.com. Recogido a 8 de noviembre en https://rewildingeurope.com/
• More than 32,000 speciesare threatened with extinction, IUCNredlist.org. Recogido a 8 de noviembre en https://www.iucnredlist.org/
• Perino, A., Pereira, H. M., Navarro, L. M., Fernández, N., Bullock, J. M., Ceaușu, S., ... & Pe’er, G. (2019). Rewilding complex ecosystems. Science, 364(6438).