Analyzing the evolution of the Earth from its “birth” to the present day involves understanding how living (biotic) components have interacted over time with non-living (abiotic) ones through increasing levels of structural and functional complexity. This process has led to the expression of organized life as we know it, beginning with single individuals, progressing to different specific populations and communities, and ultimately encompassing the various environments as a whole.
Ecological studies have led to the view that ecosystems are not static but dynamic entities, composed of communities that can change over time due to factors external to the ecosystem itself, such as climate or geology. The resulting interaction between mutated communities within the same ecosystem determines further steps toward other changes. This implies that environmental protection cannot be conceived as exclusively conservative. However, human actions have significantly accelerated ecosystem transformations, often towards configurations that are detrimental to biodiversity and the use of natural resources by human society. In other words, biodiversity does not simply provide aesthetic value to an ecosystem, but makes it more stable and resistant to disturbance and better able to provide goods and services (Galassi, Ferrari, Viaroli, 2014).
The idea of “ecosystem goods and services” arises from the observation of how nature, in its various components, represents a value for our species. This concept also stems from environmental economics, which considers natural goods as positive values that can be accounted for in the market system.
In September 2000, the 55th UN General Assembly identified priority goals for global development in the new millennium. The final document, the Millennium Ecosystem Assessment (MA), explicitly stated that achieving these goals depended on the conservation of diverse ecosystems. In this context, the following year, a UN project was launched to identify and assess changes in ecosystems and their effects on human well-being. Specifically, Goal 7 of the MA aims to ensure environmental sustainability by integrating into national policies all measures capable of halting and reversing the loss of environmental resources. We can therefore affirm that humanity’s dependence on natural resources and ecosystem services becomes a paradigm centered on two pillars: ecosystems and biodiversity.
But what exactly do we mean when we refer to these “services”? The MA has produced summary documents that classify and evaluate the main ecosystem services in relation to human well-being. These services are grouped into four categories: provisioning, regulating, cultural, and supporting services (see table).
It’s easy to understand what provisioning services are, given that humanity has relied on them daily since prehistoric times. Let’s first consider the food nature provides us directly through fishing, hunting, and gathering, as well as the food we have learned to cultivate thanks to fertile soil. Let’s also consider the textile fibers we obtain from plants like cotton, linen, or jute, and from animals like wool.
Plant biomass stores energy absorbed from CO2, which can be released through the combustion of cultivated biomass, hydrocarbons, or fossil fuels. However, using fossil and non-fossil biomass releases the stored CO2 back into the atmosphere, further accelerating climate change.
We must also remember the large number of molecules present in plants that have healing properties.
But the most important service is the supply of fresh water, especially drinking water. Finally, we must emphasize that all living organisms are “containers” of genetic resources, only partially explored, that can provide solutions to problems not yet identified or exploited. Genetic heritage has great intrinsic value because it contains the evolutionary history of life on Earth.
Most of these regulatory services are provided by plants. We all know how essential oxygen production and CO2 reduction are for the survival of all animals on the planet and for climate regulation. Locally, plant cover, land use, and the presence of water determine the characteristics of the microclimate by regulating temperature and precipitation. On a global scale, ecosystem processes influence the release of greenhouse gases (carbon dioxide, methane, and nitrous oxide) and the planet’s climate. Vegetation regulates temperature not only through soil shading but also through canopy evapotranspiration.
The established vegetation found in temperate zones in ponds and coastal wetlands, and the mangroves that border the marine waters of tropical areas, effectively prevent and reduce damage caused by extreme weather and climate events.
It should also be noted that ecosystem structure and processes control the hydrological cycle, from evapotranspiration to the regulation of surface and groundwater. Therefore, it is never advisable to implement significant changes in land use or the hydromorphology of areas (such as extensive construction) to avoid altering both the quantity and quality of water resources.
Interactions between different ecosystem elements develop systems that control human pathogens (fecal bacteria, etc.) and pathogen vectors (ticks, mosquitoes, etc.). Examples include the ciliated protozoa found in wastewater treatment plants that prey on fecal bacteria, and Gambusia, small fish that feed on mosquito larvae.
However, the plant species so important to the ecosystem’s animal life also require the help of pollinating animals, primarily insects, to produce fruit and seeds.
The diversity of human cultures is shaped by the unique characteristics of each ecosystem. In this way, the cultural services provided by ecosystems depend on the features of each habitat. From building materials to aesthetic values, these can influence the spirituality and even the religion of the community living in that particular environment. In this context, the relationship with nature supports the educational process and the development of skills, becoming a source of inspiration for art, folklore, and architecture. These elements, along with the aesthetic values expressed by landscapes and captivating natural sites, can be assigned market values that promote eco-friendly tourism.
The three categories of services we have briefly discussed depend on processes occurring within the ecosystem, while support services involve all components of the different types of ecosystems simultaneously: we are talking about primary production, material cycles, and habitat maintenance. Primary production is the fundamental engine that sustains life on Earth, forming the basis of all food chains: it is the process through which autotrophic organisms (plants, some animals, and certain bacteria) convert inorganic matter into organic matter using solar energy. In terrestrial ecosystems, the organisms responsible for primary production are plants, while in aquatic environments this role is primarily played by algae.
Primary production in terrestrial ecosystems is influenced by the quantity and quality of water, which, through the changes in physical state that characterize its cycle (evaporation, condensation, precipitation), also determines the type of climate in different ecosystems (see the following diagram).
Among the material cycles, the carbon cycle is very important. It is centered on photosynthesis and mainly affects vegetation and surface soil, where biomass and the residues of living organisms (roots, fungi, microfauna, microorganisms), dead organisms, and organic matter at various stages of decomposition predominate (see the following diagram).
Nitrogen, despite being the most abundant gas on Earth, is an inert gas that makes up much of the Earth’s atmosphere. However, if nitrogen existed only in gaseous form, life on Earth would not be possible because no organism can produce amino acids or nucleic acids—compounds essential for life—without nitrogen bonded to hydrogen. Therefore, it is necessary to obtain nitrogen in assimilable forms. Nitrogen fixation is the process by which molecular nitrogen (N2) is incorporated into organic compounds by bacteria found in the soil or living in symbiosis with the roots of legumes and other plants. Below, we provide a diagram from Wikipedia that summarizes the cycle of this vital element.
Finally, we would like to highlight two other elements that play significant roles in life on Earth: phosphorus and sulfur. Phosphorus is essential for energy metabolism, while sulfur is mainly found in marine waters and in the uppermost layers of the Earth’s crust (lithosphere).
Finally, habitat maintenance is the practice of conserving, protecting, and restoring natural ecosystems to safeguard biodiversity. In Europe, the primary framework is defined by the Habitats Directive and the Natura 2000 network. Operational strategies for habitat maintenance include the establishment of protected areas; the restoration of degraded environments; sustainable forest management; and the adoption of low-impact agricultural and urban practices, such as reducing pesticide use and decreasing the frequency of grass mowing to preserve essential microhabitats for insects and pollinators.
Credits
Author: Anna Lacci is a science communicator and expert in environmental education, sustainability, and place-based teaching. She is the author of documentaries, nature books, workbooks, interdisciplinary teaching resources, and multimedia informational materials.
Translated by Maria Antonietta Sessa
