The grid’s relationship with the surrounding natural environment and its impact on biodiversity assume different characteristics during the construction and of new lines and the operation of existing ones. During the construction stage, the impact on biodiversity is connected with the activities on the work site: the opening of passageways in order to erect the towers, excavation of the earth, and the removal of left-over materials. The construction of new lines and stations requires special attention if it takes place in the vicinity of or inside protected areas. 

Once the line has been constructed, it has a two-fold relationship with biodiversity. On the one hand, the route of the line can be a factor of growth for biodiversity and protection for several species. For example, when lines cross large open areas or extensive areas of grain monoculture, the towers and their bases constitute “islands” of concentrated biodiversity. Tower bases – especially the larger ones that support high-voltage lines – are the only zones spared from intensive agriculture, with its working and transformation of the land. These are places where spontaneous grasses and brambles flourish in which wild rodents find shelter, because their den systems are not periodically destroyed by plowing. They are also places with concentrations of predators of the rodents, i.e. birds of prey. In effect, birds, especially rapacious ones, commonly use electric lines and their towers as both posts for observing the surrounding area and structures for nesting. 

On the other hand, lines have potentially negative effects on biodiversity that regard birds in particular. The risk of electrocution should not concern Terna’s lines, because it is connected with the narrow space between the typical wires of low- and medium-voltage lines, which can electrocute birds – especially large ones – that cross their route. However, high-voltage lines can entail the risk of collision. The actual occurrence of collisions depends on the density of the birdlife and the frequency with birds of transit fly in the vicinity. The important factors in this regard are the routes of migratory bird – which are especially important in Italy, a bridge between Europe and Africa – the location of wetlands in the area, and the presence of protected areas, reserves, and parks.