Resilvestración (Rewilding): what is it, what is it for and how does it work

Human beings are increasingly increasing their consumption of natural resources, resulting in environmental changes at the ecosystem level and globally. The damage we cause to the planet is quantifiable, because according to the International Union for the Conservation of Nature (IUCN), 32,000 species of living things are currently in danger.

The picture is hardly more encouraging if we move to more precise figures. For example, scientists hypothesize that by reading these lines, 150 to 200 species are disappearing every day. Many of them will never be discovered or classified, a daunting reality for any biologist or nature lover.

As all of this data indicates, it’s time to take action. Sometimes the anthropogenic changes are completely irreversible and it remains only to try not to repeat such crimes against the ecosystem, but other times conservation biology has certain tools up its sleeve.

This is the case with resilvestración or rewilding, by means of which human beings try to restore the atmosphere to the balance it deserves.. Here we tell you all 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.

    Resilvestración or rewilding: returning to the planet what belongs to it

    Resilvestración is defined as a conception of large-scale conservation, intended to restore and protect natural areas by reintroducing key species and promoting connectivity between areas disaggregated by human activities.

    Initially, the term rewilding was coined to implement certain strategies aimed at reintroducing key superpredatory species into an ecosystem, thus seeking to restore its trophic balance. The wolves of Yellowstone, which were released into the park after the massive timber growth that led to this hunter’s demise in 1926, are a clear example of this.

    The truth is that today resilvestración covers a much more multidisciplinary terminological umbrella. It is not just a matter of reintroducing species, but of restoring the ecological integrity of the environment and reducing human impact. pretty much the same. The goal is clear and concise: we are seeking ecological restoration to the point where the ecosystem is able to self-regulate – naturally again.

    The basics of resilvestment

    Resilvestración is based on the analysis and action on three essential pillars of the ecosystem: trophic complexity, natural alterations and connectivity. We then dissect each of these bases in detail.

    1. Trophic complexity

    This is the most similar approach to the original reforestation concept. Large herbivorous animals generate various influences on the ecosystem in which they are found, because, with their weeding and plant-consuming activity, they directly affect other taxa such as small birds, small mammals, insects and plants. plants. Natural ecosystems are in absolute balanceAs super predators, keep these large living things at bay so that their activity does not get out of hand and any environment becomes a drought.

    When the human being puts his hand where it does not correspond, this balance can be drastically upset. Whether for lack of prey, destruction of feeding sites or direct hunting, in many cases, these and other key predators end up feeling the effects of anthropogenic changes, Which results in a drastic reduction in their population and even a subsequent complete disappearance.

    Trophic regeneration is not only aimed at reintroducing species that were previously in the ecosystem and were essential for their maintenance, as it can also be treated as part of a passive and preventive approach. Human coexistence with species in the ecosystem can be encouraged or legislated behind limiting or banning the hunting of endangered living things, and this is called passive reforestation.

    In the event that the species of interest has completely disappeared its reintroduction or ecological replacement can be considered (Changing a species for a more suitable species in the ecosystem which has lost its equilibrium with the same function), although the effects of the latter technique can be very dangerous in the long run. Of course, when modifying ecosystems, you have to use the lead feet, as the effects can be irreversible.

      2. Natural alterations

      While it may not seem like it 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 caused by a normal climatic regime can lead to encourage the reconfiguration of ecosystems and their species, resulting in greater biological heterogeneity.

      In anthropogenic environments, natural alterations are usually suppressed or controlled deterministically, which can lead to disasters on a much larger scale (for example, several small fires can prevent a massive fire in the future). This pillar of rebuilding seeks to rediscover the stochasticity of natural events: it is not a question of controlling everything by human beings, but of that the ecosystem regulates itself in the most logical way possible.

      3. Connectivity

      Connectivity is essential between living populations because gene flow prevents the effects of genetic drift from being detrimental to species in nature. Without wanting to go into genetic terms that escape this opportunity, we can summarize this whole process in the following concept: a new individual visiting a population is a breath of fresh air, because he can bring new variations in their genes that will be transmitted, by reproduction, to future generations.

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

      This branch of reforestation solves this problem through the creation of ecological corridors (Structures that allow animals to move despite human constructions) or simply by avoiding the construction of these structures at first. Population connectivity measures are manifold, but the general objective is to try to restore the gene flow that has occurred naturally in the ecosystem.

        some examples

        Everything does not remain in theory, because resilvestración has been put into practice on several occasions. There are portals like this that bring together various events in which an attempt has been made to restore the balance of many ecosystems strongly influenced by human action, either by basing efforts on one of the pillars presented or by using a multidisciplinary approach.

        Many of these projects go beyond reintroducing predators. For example, in the Côa valley in northern Portugal, it is being explored the reintroduction of domesticated and semi-free herbivorous species, in order to increase grazing activity and thus avoid the presence of shrubs and vast lands susceptible to fires.

        Another of the cases resounded at the moment is the resilvestración of the central Apennines of Italy. In this case, the creation of the ecological corridors mentioned above is encouraged, conservation measures to increase the population of the bear Ursus arctos marsicanus and promotion of ecological tourism.

        As we can see, not all rewilding events are based solely on the introduction of live specimens of key species: in most cases a multidisciplinary approach is necessary.


        As we have gathered in this sense, the concept of reforestation has undergone an evolutionary process over the last decades, where the integration of multiple parameters is sought: restore trophic complexity, give way to natural alterations and promote the connectivity of populations. Beyond that, it also seeks to legislate in favor of the protection of vulnerable ecosystems and their species, to encourage the interest of populations for the natural elements that surround us and promote coexistence between the environment and human activities.

        Reforestation has a specific goal: 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.

        Bibliographical references:

        • Please make Europe a wilder one, Retrieved November 8, from
        • More than 32,000 species are threatened with extinction, Retrieved November 8 from
        • Perino, A., Pereira, HM, Navarro, LM, Fernández, N., Bullock, JM, Ceaușu, S., … and Pe’er, G. (2019). Strengthen complex ecosystems. Science, 364 (6438).

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