Around the world, natural ecosystems provide seemingly endless goods and services we depend upon to survive. Healthy ecosystems are responsible for the production of oxygen, food, clean water, construction materials, medicines and much more besides. They also store carbon from the atmosphere, regulate the climate, protect our shorelines, purify air and water, provide aesthetic beauty and a wide array of recreational activities. In a world overwhelmed by human disturbances, degradation of nature is more and more widespread. The decline of biodiversity along with the loss of ecosystem functions and services is a threat to nature and human life. However, the growing awareness of the value of nature has given rise to an increasing interest to restore these precious natural ecosystems and the services they provide.
We live in the anthropocene, an era marked by drastic transformations caused by humans to the natural environment. Since then, nature is increasingly subjected to many pressures and disturbances. Human activities such as urbanisation, globalisation, water use, energy consumption and land transformation have brought serious consequences, including increased greenhouse gas levels, deforestation, climate change, ocean acidification, biodiversity loss and decreased water, soil and air quality. Many of the health challenges that we face today, including infectious diseases, non-communicable diseases and malnutrition are related to these changes to the natural environment. We observe a dramatic increase in non-communicable diseases such as autoimmune conditions, allergic diseases, cancer, neuropsychiatric disorders, obesity and cardiovascular disease to name a few. Air pollution is killing 7 million people worldwide every year and harming billions more. The rise in infectious diseases such as Ebola, HIV, SARS and COVID 19 are likely directly connected to deforestation and wildlife trade. Additionally, an increased frequency of droughts, floods and stormy events as a result of climate change is exposing entire populations at great risks. Consequently, there is an urgent need to minimize our impact on nature, not only by preserving what is left but by restoring the damage already done..
One of the earliest well-documented restoration effort took place in Brazil in 1862, when major Manoel Archer had for mission the restoration of the Tijuca Forest, which had been converted to sugar and coffee plantations. Over 100,000 seedlings were planted as deforestation endangered the supply of drinking water to the city of Rio de Janeiro. In the United States, the practice of restoring degraded areas started in the 1930’s, when Aldo Leopold restored meadow vegetation and planted pines to reduce soil erosion on his land. Since then restoration efforts increased globally and so did the science.
Restoration ecology as a science is a rather new discipline, which was developed over the past decades. It aims at facilitating and speeding-up the recovery of lands and waters after their degradation or destruction by humans. Restoration ecologists seek to re-create the structure and dynamics of altered ecosystems and re-establish authentic plant and animal communities. Restoration ecology integrates many disciplines such as ecosystem ecology, botany, zoology, sociology and economy but also hydrology, oceanography and geomorphology. However, even with all scientific advances in several knowledge areas, the complexity of nature brings many challenges to restoration actions. Indeed, natural ecosystems are the result of a long evolution over millions of years, while we intend to restore or re-create such ecological systems in a short amount of time. Restoration efforts are therefore not always successful due to the many filters preventing recovery.
Despite all the challenges, nature seems to be willing to help us in this arduous mission to restore degraded ecosystems. A traditional way of restoring land vegetation, such as forests or grasslands, consists of an active re-introduction of desired species either by planting or sowing, while taking biotic and abiotic filters in consideration as these factors can hinder the success of establishment and survival of the introduced species. Interestingly, researchers have found new tools for ecological restoration of such ecosystems. Some animals have been identified as ecological engineers due to the strong influence that they have on their environment. Indeed, some animals can modify their surrounding, positively affecting other species by creating new habitats. For instance, animals eating fruits, called frugivores, unintentionally disperse the seeds away from the mother plant. These frugivores, mainly birds and mammals, transport the fruit, feed on it and leave the seed, which facilitate recolonisation of native vegetation in degraded lands and increases plant and habitat diversity. In France, scientists are using ants for restoration of grassland species. Some ant species feed almost exclusively on seeds, transporting them to their nest. Some of the seeds may be lost, or discarded during transportation causing their dispersal away from the mother plant and favouring new colonisation. Another famous example of ecological engineer is the beaver, used for restoration of wetlands. Beavers are capable of changing terrestrial habitat into submerged aquatic habitat through the construction of dams. A study showed that they could transform an agricultural land into a species-rich and heterogeneous wetland environment. The restoration of a wolf population in Yellowstone national park, following 70 years of absence due to extermination, has had a tremendous effect on the entire ecosystem, modifying the vegetation and bringing many animal species back to life.
Nature degradation has a price we cannot afford if we want a peaceful and healthy future. It is now very clear that damaging the Earth is damaging ourselves, as we are a part of nature. In 2019, the United Nations declared the UN decade of ecosystem restoration, placing ecological restoration at the forefront of national agendas. The critical role of ecosystem restoration was recognized by the United Nations as the way for improving human well-being around the world and for reconnecting people to nature. The recent advances in ecological restoration shows that nature itself can be used as a tool for its own recovery. The use of ecological engineers is a recent and promising discovery. However, restoration should never be used as an argument to justify activities giving rise to environmental degradation. Businesses cannot continue as usual, and the world should stop expecting scientists to clean up the mess. Our civilisation needs to adopt new practices, less destructive and favouring a healthy and biodiverse environment. The time has come for us to stop working against nature, but with nature.
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World Health Organization https://www.who.int
Food and Agriculture Organization of the United Nations http://www.fao.org