The volcanic complex, thanks to its isolated position and the presence of both Mediterranean and continental ecosystems, is an important zoogeographical crossroads. The proximity to the coastal strip, the fact that it is the only relief placed at the centre of the Campania plain, the favourable climatic conditions and the great environmental diversity make it an important resting place and refuge for the migratory fauna and have allowed, in a territory of modest extension, the presence of an interesting fauna community, protagonist, such as plant species, of repeated colonization following the cyclical eruptions of Vesuvius.
Birds are the most represented group in the Park area, with about 150 migratory, wintering or nesting species. The proximity to the coast favours the stopover of species that, coming from the sea, identify in the silhouette of the volcano an important point of reference near the coast and a place where to stop after crossing the Mediterranean. Some species are included in the Habitats Directive, such as the Peregrine (Falco peregrinus), which nests in the inner walls of the Great Cone.
Reptiles find ideal conditions for reproduction on the volcanic complex and Vesuvius is therefore an area of great importance for the conservation of these animals. There are eight species, the most widespread of which is the harmless Biacco (Coluber viridiflavus). The lack of surface water limits the presence of amphibians; the European green toad (Bufotes viridis) is widespread on the eastern, northern and western slopes of the volcanic complex; this species, protected by the “Habitats” Directive, has characteristic emerald green spots on its back and concentrates its reproductive effort in a few days, in spring, exploiting the ephemeral pools of the first rains.
Some species of bats are at risk of extinction and are protected by the Habitats Directive, aimed at the conservation of species and ecosystems considered at risk at European level. The mere presence of these species has determined the establishment, in the area of the volcanic complex, of two Sites of Community Importance (SCI areas) whose extension coincides substantially with the perimeter of the protected area.
Forestry operations over the last century have transformed the communities of mammals present in the Vesuvian area. Today29 species have been found, almost all of which are nocturnal, 11 of which are represented by bats that are extremely important from a conservation point of view.
A recent research has allowed us to census 1229 species of arthropods, many of which have significant fauna and / or biogeographical interest, and some are present only on the volcanic complex. Detailed researches have been carried out on lepidoptera: 44 species of diurnal butterflies have been surveyed, which represent a different population compared to the other mountainous massifs of Campania, due to the particular climatic, geographical and vegetational conditions of the volcanic complex Somma-Vesuvio.