Description
The place-name 'Grave', with all its local variants, nowadays indicates a gravel, a heap of gravel or a place where gravel or stones are dumped. The portion of Doss Le Grave included in the Biotope is precisely made up of a large amount of porphyry 'gravel', which gives the area a very suggestive 'semi-desert' appearance.
The origin of this particular environment is linked to human activity: the imposing accumulation of gravel and stones is in fact made up of waste material from the silver mining activity that, in the years from around 1000 to 1500, affected the entire Calisio-Argentario plateau.
The environment of the 'grava' presents pronounced arid conditions of the soil and this strictly conditions plant life.
Species typical of arid places grow there, such as the globularia (Globularia cordifolia) and the raven pear (Amelanchier ovalis). The vegetation is macroscopically characterised by a large number of Scots pine (Pinus sylvestris) specimens, which, due to the poverty of the soil, grow very slowly and stuntedly and have systematically taken on the appearance and shape of genuine natural bonsai trees, no more than one and a half metres high. Some have such beautiful forms that they would appear well in manuals that teach the art of bonsai, giving the landscape a vaguely oriental appearance or, if you prefer, that of certain Mediterranean thickets where the Phoenician juniper is present.
The arid portion of the biotope makes immediate contact with the wetland below. This is a peat bog that originated by the filling in, by aquatic vegetation, of a small lake basin. Small pools of free water still remain in the centre of this basin (these pools are called 'peat bog eyes').
The vegetation consists partly of sedges (with several Carex) and partly of dense stands of sedge (Cladium mariscus), another rather rare Cyperaceae. The peat bog is home to some authentic botanical rarities, including some marsh orchids and the splendid marsh gladiolus (Gladiolus palustris); the presence of the water lily (Nymphaea alba) and the utricularia (Utricularia minor), an insectivorous plant that lives completely submerged, in the ponds should also be noted.
The faunal aspects of this biotope are also very interesting, because, like all wetlands, it is a refuge for environmentally demanding animals such as amphibians and water birds.
In addition, many other birds can take advantage of the environmental richness offered by the aquatic ecosystem; here, the availability of resources is greatly amplified by the extreme and unusual proximity of the wetland and arid environment.