The insularity of Sardinia has determined the evolution of a very specific and occasionally original plant life, i.e. endemisms. Endemisms or native plant species can be living relicts of ancient, now extinct flowers (palaeoendemisms) or of more recent genesis (neoendemisms) resulting from climatic, ecosystematical and genetic events or environmental conditions.
a) Plants which are known only in Sardinia;
b) Plants which are common in Sardinia and Corsica;
c) Plants which can be found in Sardinia, in Corsica and in the Balearic Islands;
d) Plants which can be found in Sardinia, in Sicily and in other places of the Mediterranean Sea.
The vegetation of the target area is mainly composed of the typical species of the Mediterranean habitat, where the climate is warm and humid with two rainy seasons and the absence of frost in winter. Plant life revives from the end of autumn up to the late springtime. In the summertime, when the plants must go through periods of drought, they slow down their activities or even rest.
We can distinguish several “climax” (final stage of the evolution of the plants in a certain habitat):
1) Climax of the coastal thermo-Mediterranean xerophiles (from the sealevel up to an altitude of 400 metres, nearly always on the sunny south-south-eastern slope): the most common species is the juniper tree (Juniperus phoenicea L.), whose coastal variety is predominant. It grows from the foot of the cliffs up to 400/500 metres where holm oaks (Quercus ilex) and junipers (Juniperus oxycedrus L.) begin to prevail.
2) Climax of the sclerophyllus evergreen thermo-Mediterranean xerophiles (from 400 to 500 metres): their most typical species are: the mastic tree (pistacia lentiscus L.), the olive (Olea europea L. variety sylvestris Miller-Brot), the spiny broom (Calicotome villosa Pouret) and the mock privet (Phillyrea angustifolia L.); we can find the following combinations: oleo-lentiscetum, oleo-euphorbietum dendroidis.
The forest.
In the north, the spread of the forest plants called “Mediterranean sclerophyllus evergreens” is limited by the low winter temperatures. The dominant species of trees in the Mediterranean regions are evergreen oaks and pine trees (Pinus sp) - absent in the target area-, evergreen trees like junipers (Juniperus sp), heathers (Erica sp) and cists (Cistus sp).
During the last centuries, man’s activities, like deforesting and the creation of pasture etc., have decisively influenced the vegetation of the area of Cala Gonone: the Quercus ilex (holm oak) has been substituted by a pseudo climax of junipers (Juniperus phoenicea). Today, man doesn’t influence the natural environment any more; a fact that stabilizes the actual situation of the vegetation that is composed of junipers (70-75%) and some tree spurges (Euphorbia dendroides), turpentine trees (Pistacia therebintus), olive trees (Olea europaea), mock privets (Phyllirrea latifolia) etc. in between.
On the eastern slope of the area, in the deepest little valleys, the forest has got a typical look: in dry and arid zones the strawberry tree (Arbutus unedo L.) and even rarer types of heathers (Erica arborea L.) have substituted the holm oak (Quercus ilex L.) and form a high vegetation of shrubs. If there are no further negative factors that could worsen the quality of the soil, it will be possible to make the authentic forest revive with the help of some sporadic pollen of the holm oak. One can find not only the jumble of sclerophyllus evergreens but also some types of deciduous trees like the ash-tree (Fraxinus ornus L.).
The holm oak forest is less common in the coastal areas – except for some sporadic spots; single, very old specimen can be found on the “gariga” of the steep coast where the rock face is nearly vertical. Single groups of holm oaks (Quercus ilex) and junipers of remarkable dimensions stand where karstic hollows guarantee their water-supply. Often they don’t exceed the height of bushes and have got thick trunks: this is a sign of their extreme physiological situation due to the lack of water and good soil.
The shrubs (“macchia”)
The natural shrubs and low trees that don’t exceed 4 metres in height (F.A.O. 1982) are called “macchia”. Here it is nearly superseded by juniper woods. It is an area thickly covered with low sclerophyllus evergreens that reach a height of 1 or 2 metres; far apart from another there are some sporadic holm oaks, whereas other species like the Phoenician Juniper (Juniperus phoenicea L.), the mock privet (Phillyrea latifolia) and the strawberry tree (Arbutus unedo) – extremely rare because of the alkaline quality of the soil – usually cover the limestone rocks. In the interior of the fossil canyon of Fuili, a vegetation has come into being whose dominant species is the oleander shrub (Nerium oleander) and – of secondary importance – the mastic tree (Pistacia lentiscus) with enormous and very old specimen.
The gariga
The gariga is the result of man’s intense activities: tree-felling, fire and the following intense use of the soil as pasture land. The impoverishment of the macchia, the absence of the strawberry tree (Arbutus unedo L.) and the sporadic presence of mock privets (Phillyrea s.l.) and mastic trees (Pistacia lentiscus L.) have created a partly open vegetation of herbs and shrubs which can be defined irregular because of the protuding rocks. The elimination of the sclerophyllus plants has favoured the development of a rich, heliophile (sun-seeking) and non-seasonal vegetation of herbs which makes the reafforestation more difficult.
