In the midst of the last forests: the need for an ecosystem approach
The native forests and the anthropic land uses are determining factors in the availability of water that flows through rivers, lakes, lagoons and other wetlands, and that finally run into the sea. Land-use changes such as deforestation and forest degradation generate negative impacts on the quality and quantity of water, so the protection of native vegetation is essential for the care of water in this scenario of climate and biodiversity crisis.
The close relationship between native forest cover and water is reflected in the environmental degradation suffered by the basins of Chile’s northern Patagonian lakes. For example, the Villarrica lake is undergoing an accelerated process of nutrient enrichment (eutrophication by the overabundance of nitrogen and phosphorus in water) that is caused mainly by human activities carried out in the basin. For example: discharge of nutrient wastes from fish farming, domestic sewage discharges, diffuse pollution generated by deforestation and degradation of native forests and shrublands, and the qualification of land for forestry and agricultural purposes, all of which generate an increase in the available nutrients in the waterways that drain into the lake.
This process, together with the prevailing weather conditions –increased solar radiation, high temperatures and the decrease in wind speed– has made green-blue algae blooms more frequent, affecting people’s health. The population and local authorities are on alert and are monitoring the toxicity of these waters due to the risk they imply for bathers and pets.
The native forests of the southern Chile (temperate rainforests) are part of the biodiversity hotspot known as “Chilean Winter Rainfall-Valdivian Forests” that correspond to relevant conservation areas at the planetary level, because they have a high degree of endemism (with species of restricted distribution found here and nowhere else on Earth), but are highly threatened, having experienced exceptional habitat loss in recent decades.
These fragile and dynamic forests, due to their exuberant cover and structural complexity, act like giant sponges that absorb rain during the wet season and slowly release water during the drier seasons. This is because forests allow rainfall to fall through the canopy and trunks and infiltrate into the soil in a better way, since roots, organic matter and leaf litter create conditions that facilitate infiltration into groundwater, providing a constant water supply. In addition, forests act by filtering contaminants, because their roots slow down stormwater runoff preventing soil erosion, landslides, and floods.
According to the Food and Agriculture Organization of the United Nations (FAO), since 1990, 420 million hectares of forests have been lost in the world, and the World Wide Fund for Nature (WWF) estimates that 47% of the forests that still exist face a high risk of degradation or deforestation by 2030.
In Chile, between 2000 and 2016, more than 206,000 hectares of native forest were lost between the regions of Valparaíso and Aysén (almost four times the area of Santiago), according to a study by the University of La Frontera. These forests were replaced mainly by scrub, bare land or grassland, and a significant proportion were finally converted to agricultural land or exotic forest plantations. To these historical causes are currently added: megafires, increasingly frequent due to the effect of climate change; selective forest logging practices, extracting the best trees to use them as wood or firewood ; and, more recently, the conversion of forest and agricultural land to residential areas in peri-urban and rural areas, amongst others.
Despite the strong pressures to which the forests in the south of the country are subjected, these natural ecosystems contribute to the well-being of millions of people on the planet, which makes their long-term protection even more urgent. These forests deliver a diversity of ecosystem services. This concept refers to the capacity of nature to deliver material and immaterial benefits to people, and advocates for a better understanding of the value of ecosystems for human well-being, making visible the link between ecosystem structure and processes and how this link generates changes on the well-being of people.
Among the services provided by these forests are those of provision such as the production of wood, the availability of foliage for medicinal use and the provision of water for human consumption; regulating ecosystem services such as: erosion control, flooding, maintenance of local microclimates; and cultural services such as opportunities for recreation, inspiration, education in nature, among others. A degraded forest stops providing these services or will provide them in less quantity and quality. For example, the experience of walking in a degraded, dry and hot forest is very different from walking in a forest with shade, lower temperatures, humid leaves and a greater diversity of fungi, plants and animals.
We are still in time to advance in solutions that allow us to protect and restore natural ecosystems and watersheds of which we are a part. Some of these solutions come from nature itself, and have been called “Nature-based solutions”. This concept proposes a comprehensive approach that includes actions to protect, sustainably manage, and restore natural or modified ecosystems, making it possible to effectively and adaptively address important societal challenges such as climate change, food and water security, or disaster risks.
Thus arises the need to promote both public and private actions that allow: (i) the protection of native forests that still exist, through the creation of public and privately protected areas, in ecosystems scarcely represented in the National System of State-Protected Wildlife Areas (SNASPE) and those that make it possible to generate ecological and hydrological connectivity between protected areas, and (ii) the social-ecological restoration of natural ecosystems, which consists of a recovery process, together with the local community, of the composition, structure, and functionality of an ecosystem that was disturbed, giving an initial impulse for that ecosystem to begin to recover and return to providing the ecosystem services it originally provided.
State initiatives such as the National Landscape Restoration Plan 2021-2030, developed by the Ministries of the Environment and Agriculture, have established as a national goal the restoration of 1,000,000 hectares of landscapes by 2030, considering the restoration of forests, riparian vegetation, coastal-marine habitats, peatlands and other wetlands. However, in addition to these concrete actions for the protection and restoration of ecosystems, it is necessary to promote a new approach for the integrated water management and water-related ecosystems, which considers the current water scarcity, the overexploitation of aquifers and surface waters and the growing challenges posed by the climate and biodiversity crisis.
Given the magnitude of these challenges, they must be addressed by society as a whole. For the state this means the design, implementation and inspections of public policies that are up to the current crises and that consider the available scientific evidence. And, on the other hand, civil society and non-governmental organizations, where our role is to promote sustainable and innovative practices that promote the protection and sustainable use of watersheds, and strengthen collaboration and dialogue between communities considering principles of good governance. In this way, we will be able to move decisively towards a regenerative development that integrates scientific and traditional knowledge to build more just, equitable and environmentally responsible societies.