Resilvestration (Rewilding): what it is, what it is for and how it works

The human being increasingly increases the consumption of natural resources, which translates into environmental changes at the ecosystem and global level. The damage we are causing to the planet is quantifiable, because according to the International Union for Conservation of Nature (IUCN), 32,000 species of living beings are, right now, in danger.

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

As all these data indicate, it is time to take action on the matter. Sometimes anthropic modifications are completely irreversible and it only remains to try not to repeat sizes crimes against the ecosystem, but at other times, conservation biology has certain tools under the sleeve.

This is the case of resilience or rewilding, through which human beings try to restore the balance it deserves to the environment.

. Here we tell you everything about this conception of large-scale conservation. Stay with us, because in terms of environmental restoration, there is still a light at the end of the tunnel.

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Resilvestration or rewilding: giving back to the planet what is yours

Resilience is defined as a conception of large-scale conservation, aimed at restoring and protecting natural areas by reintroducing key species and promoting connectivity between areas broken up by anthropic activities.

In the beginning, the term rewilding was coined to implement certain strategies focused on reintroduce key super-predatory species into an ecosystem, thus seeking to restore balance trophic of the same. A clear “book” 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 the year 1926.

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

The foundations of resilience

Resilience is based on analysis and action on three essential ecosystem pillars: trophic complexity, natural disturbances and connectivity. Next, we break down each of these bases in detail.

1. Trophic complexity

This is the closest approach to the original rewilding concept. Large herbivorous animals generate various influences on the ecosystem in which they are found, since, with their activity of browsing and consumption of vegetables, directly affect other taxa such as small birds, micro mammals, insects and plants. Natural ecosystems are in absolute balance, because the super predators keep these large living beings at bay so that their activity does not get out of control and basically any environment becomes a dry land.

When the human being puts his hand where it does not belong, this balance can be drastically upset. Either due to lack of prey, destruction of feeding places or direct hunting, in many cases these super predators and other key species end up suffering the effects of anthropic modifications, which translates into a drastic reduction in 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, as it can also be addressed under a passive approach and preventive. The coexistence of the human being with the species of the ecosystem can be promoted or legislate in order to limit or prohibit the hunting of threatened living beings, and this is known as passive rewilding.

In case the species of interest has completely disappeared reintroduction or ecological replacement can be contemplated (change a species for another more suitable in the ecosystem that has lost the balance with the same function), although the effects of this last technique can be very dangerous in the long term. Of course, when altering ecosystems, it is necessary to tread lightly, as the effects can be irreversible.

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2. Natural disturbances

Although it may not seem so at first glance, not all natural disasters are negative at the ecosystem level. For example, the emergence of biological pests, small-scale fires or floods produced by a climate regime normal can promote the reconfiguration of ecosystems and their species, which translates into greater heterogeneity biological.

In anthropized environments, natural disturbances are usually suppressed or controlled deterministically, a fact that can lead to catastrophes on a much larger scale (for example, several small fires can prevent a massive one from occurring in a future). This pillar of rewilding seeks to recover the stochasticity of natural events: it is not about everything being controlled by the human being, but about the ecosystem to regulate itself in the most logical way possible.

3. Connectivity

Connectivity is essential between populations of living beings, since gene flow prevents the effects of genetic drift from ending up being deleterious to species in the wild. Without going into genetic terms that escape this opportunity, we can summarize this entire process in the following concept: a new visiting individual in 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 ones generations.

Unfortunately, many man-made structures directly limit or cut off connectivity between populations. Something as simple as a road can be an insurmountable barrier for many living beings, a fact that prevents the interaction between different population centers of the same species.

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

• You may be interested in: "Genetic drift: what is it and how does it affect biological evolution?"

Some examples

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

Many of these projects go beyond the reintroduction of predators. For example, in the Côa Valley of northern Portugal, exploration the reintroduction of domesticated and semi-free herbivorous species, in order to increase grazing activity and thus avoid the presence of bushes and large areas susceptible to fires.

Another of the cases sounded today is the resilvestration of the central Apennines of Italy. In this case, the creation of the aforementioned ecological corridors is being promoted, conservation measures to increase bear population numbers Ursus arctos marsicanus and the promotion of ecological tourism.

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 necessary.

Resume

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

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

Bibliographic references:

• Making Europe a wilder place, rewildingeurope.com. Picked up on November 8 in https://rewildingeurope.com/
• More than 32,000 species are threatened with extinction, IUCNredlist.org. Picked up on November 8 in 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).