Urban Expansion, Land Cover, and Soil Ecosystem Services
By Ciro Gardi, Scientific Officer, Animal & Plant Health Unit, European Food Safety Authority, Parma, Italy
We are aware, especially the readers of this blog, of the immeasurable value of soil and of its unique and essential role. The focus of the Global Soil Biodiversity Initiative is the variety of living forms that soil can host, and it is clear that in order to have soil biodiversity we need to have soil. In other words, we will not be able to protect soil biodiversity if we are not protecting the soil as whole. Unfortunately, there are several processes leading to soil degradation and the intensity and combination of them vary across the globe.
One of the most irreversible process, often overlooked, is represented by soil sealing, consequent the expansion of urban and industrial areas or the construction of transport infrastructures. The intensity of this process can be extremely high, especially in the countries with fast economic and/or demographic growth, and often it occurs at the expenses of the most valuable and fertile soils. After the soil is sealed, due to the construction of buildings, roads, etc., all the soil ecosystem services are lost or severely compromised. Not only to the capacity of soil to be used for agriculture, but also its capability to infiltrate water, to store carbon, etc.
A newly published book, Urban Expansion, Land Cover and Soil Ecosystem Services, is an accurate overview of the impact of urban expansion processes on the provision of soil ecosystem services. From the analysis of the magnitude and intensity of these processes at global scale, to the assessment of the impact of soil sealing and land take on the capability of soil to produce food and biomass. The role of soil in agricultural production is probably the most obvious: according to FAO, 95% of our food derive directly or indirectly from soil, and by to 2050 we will need to increase the food production by 70%. There are however other soil ecosystem services essential for human wellbeing, and more in general for the protection of life on the Earth. The regulation of water cycle and most terrestrial biogeochemical cycles rely on soil. The existences of the majority of terrestrial ecosystems also depend on soil.
Often new residential, commercial or industrial buildings are realised only for speculative reasons and remain unused for ever. Photo credit: Ciro Gardi
Soil sealing prevents, or strongly compromise all soil ecosystem functions. This is an example of an exception: the vigour of this plant is able to break the asphalt coverage sealing the soil. Photo credit: Ciro Gardi
An example of a construction site. Soil is subject to several types of
degradation processes: compaction,contamination and finally sealing.
Photo credit: Ciro Gardi
It is essential then to have a more responsible use and planning of this strategic and pivotal non-renewable resource, sharing our knowledge of its values and role, with policy makers, land use and urban planners, but also citizens. In Europe, a public campaign has been recently launched (People4Soil - https://www.people4soil.eu/en ) to request the declaration of a soil protection Directive at the EU level. This is an example of the efforts of awareness raising that made possible to spread among citizens the comprehension of the role of soil, as essential element of the natural capital.
Learn more about the book here: