Biodiversity

One of the characteristic traits that make the “Assisi-Spoleto Olive Belt” totally unique, also in terms of biodiversity, is the climate. Umbria is a continental region, not Mediterranean like the zones of origin of the olive tree, with very rigid winters. For this reason, the olive fly is rare, and the dimensions of the tree and olives are smaller. In addition, every thirty years or so a frost occurs that kills most of the plants, which have to be felled. The new shoots, sprouting up from the tree base, are selected and only after four years the new olive trees take the place of the old ones.
These factors, which might appear to be misfortunes or catastrophes, are in reality the key to success, because the end product is guaranteed a quality of the utmost excellence. In addition, there is another element having to do with geology and exposure. The mountains of the piedmont belt of the pre-Apennine chain shield the “Spoleto valley” from the cold winds, and intercept the rains coming from the west. Lastly, the calcareous nature of the soil provides an ideal drainage for the trees, together with the availability of water that permeates the subsoil even during the summer season

The distribution of the olive groves in Umbria is not random, but closely tied to the ecological conditions of the territories, as is the case with the vegetation and fauna. For this reason the olive trees along the “Assisi-Spoleto Olive Belt” are examples of a specificity that is impossible to find elsewhere. The biodiversity of its flora and vegetation is typical of the landscape of the downy oak. From the vegetation standpoint, specifically speaking, the communities that develop within the olive groves of the Belt belong to the order Brometalia rubenti-tectorum. These are annual herbaceous communities characterized by the presence of segetal species (weeds). We thus find a perennial vegetation of chasmophytes and sometimes chomophytes, which develop in the crevices of rocks and walls, and is characterized by the presence of small ferns and small Crassulaceae.

In some cases, the south-southwest exposure of the mountain belt ensures the existence of particular temperate microclimates which, in localities such as Pale, shielded by the crag towering over it, or Trevi, see the proliferation of exotic plants such as agaves and prickly pears. But among the unique species of the Olive Belt, worthy of mention are certainly the orchids, species which have a particular importance from the conservation standpoint. If an olive grove is abandoned, within ten years’ time its area becomes colonized by species such as the downy oak and the hornbeam, which are much more suitable to the “continental” climate of Umbria than the olive trees is. Lastly, the southern exposure of the piedmont belt is conducive to the presence of native and primitive tree species such as the strawberry tree and, in particular, the holm oak.

The fauna is also rich and characteristic. The “Assisi-Spoleto Olive Belt” is home to numerous large mammals that find abundant food resources here, like the common hare, the porcupine, the roe deer, and the boar. The olive grove offers shelter to many tetrapods. These species include micromammals such as the wild mouse and the squirrel. Among the reptiles there is a large presence of members of the Lacertidae family, i.e. the wall lizard, field lizard, and green lizard. There are also numerous birds, for example the black bird, the great tit, the Eurasian blue tit, the Eurasian blackcap, the hoopoe, and the pheasant. The presence of so many animals also means that the olive grove is also inhabited by the so-called “secondary consumers” or “alpha predators” which feed on them. Among the reptiles, such predators are the green whip snake and the Aesculapian snake, which hide among the rocks of dry walls to await their prey. Among the birds, there are diurnal species such as the common buzzard and the kestrel, and nocturnal ones such as the little owl and the barn owl. Among the mammals we find the fox and the beech marten, and in the “wilder” areas the wildcat, the pine marten, and even the wolf.

To safeguard the natural treasures of these lands, the Region has set up the “Regional Observatory for Biodiversity, Rural Landscape, and Sustainable Planning” at Villa Fabri in Trevi. It is a research center where the Universities of Perugia, Camerino, and L’Aquila work, as participating members of the Villa Fabri Foundation. The fundamental objective of the Observatory is to collect and make available, in a single information system open to the public, the regional data on biodiversity in its broadest and most complete sense, with particular emphasis on the rural landscape.

The Observatory also has other objectives, such as: studying, monitoring, and assessing the transformations of the rural landscape, of the natural elements present in the landscape mosaics, of the general processes of the sector policies, and of the cumulative effects on the landscape, formulating corrective actions to remedy any problems that may be found. The observations and studies have, as their common theme and constant perspective, the strategy of sustainability. In addition, the Observatory provides the information necessary for permitting an economic assessment of the biodiversity, at the basis of a sustainable use of this resource.