MINISTRY OF ENVIRONMENT
AND ENERGY SECURITY

asino bianco e piccolo
Asinara
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Asinara Park

Terrestrial flora

The territory of Asinara has undergone intense human use of resources in recent years, which has affected the plant landscape in particular. Especially inland areas are sometimes altered and degraded due to agricultural, forestry and livestock uses exercised over time.

The first comprehensive study of the island’s flora is that of Bocchieri (1988) supplemented and revised by more recent reports that flow into the Portal on the Flora of Asinara National Park (
https://dryades.units.it/asinara/index.php
) and which reports for the island the presence of nearly 700 botanical species and subspecies.

The numerically most represented families are the Asteraceae, Fabaceae, and Poaceae.

Endemic species

There are several plant endemics on the island, i.e., plants whose distribution range is limited to a specific area; their number is 30, about 5 percent of the total flora, with species exclusive to Sardinia, common to Sardinia and Corsica and other islands in the western Mediterranean.

All of them deserve special attention as endemic. Two specifically are protected by the EU Directive 92/43/EEC called “Habitat” which aims to contribute to the preservation of biodiversity. By the Directive they are considered of priority importance for conservation. These are:


Centaurea horrida,
the spiny cornflower, an endemism exclusive to Sardinia found in the coastal garrigue from Punta Salippi to the highest cliffs of Punta dello Scorno. It forms pure stands and lives on various substrates (granite and schist in Asinara, limestone in other areas) as long as special climatic conditions exist.


Anchusa crispa
ssp.
crispa
, the beach bugloss, endemic to Sardinia and Corsica, located in Cala Spalmatore beach.

Other endemics worth mentioning include:


Limonium laetum
, Asinara limonium, exclusive to Sardinia, a rare and localized plant. It is found in the southern coastal ponds of Fornelli, Cala Reale, Campu Perdu, and the small beach of Cala d’Oliva.


Limonium acutifolium
, the acute-leaved limonium, found along the entire coastal coast of the island, is a characteristic species of the first strip of coastal rocky vegetation, which especially from June to September lends an element of color to the arid rocky shores.

Other endemisms that are particularly interesting from a phytogeographic point of view are those that testify to the territorial continuity of the Sardinian-Corso massif, such as:


Astragalus terraccianoi
, Terracciano’s astragalus, which lives in characteristic cushion formations along with
Centaurea horrida
. It has the appearance of a rounded bush with short, thorny branches but a bright green color that differentiates it from the
Centaurea
.


Erodium corsicum
, the crane-beaked geranium of Corsica, which lives all along the coast along with the sharp-leaved limonium, where it enters rocky ravines most exposed to salty winds.


Filago tyrrhenica
, the evax of Gallura, a small herbaceous plant with rosette habit, a littoral species that lives in dry meadows with sandy soils and tends to cover the ground.


Nananthea perpusilla
, the tiny daisy, a dwarf plant among the smallest species in the Italian flora, grows in subsalt depressions at marshes and reefs, always and exclusively by the sea.

Vegetation

The vegetation of the island has been investigated in detail by Pisanu et al. (2014) where they describe the main communities and associations found on Asinara. The landscape is strongly affected by anthropogenic pressure related to the former presence of the prison and health station and land use due to the activities of the agricultural penal colony.

Much of the island is characterized by the dominance of Mediterranean scrub, consisting of evergreen shrubby plants, with color aspects related to the changing seasons. Various types of scrub are identified depending on the prevalent or characteristic species: lentisk (Pistacia lentiscus) and olive (Olea europaea var. sylvestris), to euphorbia (Euphorbia dendroides), thorny broom (Cytisus laniger), to marine cistus (Cistus monspeliensis), with small white flowers and a distinctive fragrance.

In the western coastal areas overhanging the sea there are: a vegetation belt more exposed to the action of marine aerosol, and characterized by the presence of species related to these conditions, such as sea fennel (Crithmum maritimum), the sharp-leaved limonium (Limonium acutifolium) and the Corsican crane beak (Erodium corsicum); and an innermost band, characterized by the association with spiny cornflower (Centaurea horrida) and Terracciano talus (Astragalus terraccianoi) forming vast garigues to which other species such as Thymelaea hirsuta and Euphorbia pithyusa are added.

The east coast alternates between sandy creeks and brackish ponds, and on the beaches live species that with their root systems fix the sands such as

Agropyron junceum, the common grass, and Ammophila litoralis or stinging sparto. Of particular naturalistic interest are the temporary ponds in the southern part of the island, with high salt concentration due to summer drying. Typical vegetation capable of withstanding changes in salinity and water levels has become established in these areas, with extensive saltcedar associations.

As for the forest cover, the situation in past centuries must have been completely different from what it is today, and human action has now reduced the forested area to a few hectares in the Elighe Mannu area, where there is an important ilex grove.

Other species belonging to the genus Quercus present on the island are a few specimens of Quercus congesta in the vicinity of Cala d’Oliva and Quercus suber, cork oak, limited to a few individuals located on the southern slopes.

Other tree species present are pines, including the domestic pine (Pinus pinea), introduced about fifty years ago and still present in the area of Elighe Mannu, Fornelli and Campu Perdu.

Other human-introduced tree species generally found near housing structures include acacia (Acacia cyanophylla), cherry (Prunus avium), plum (Prunus domestica), chestnut (Castanea sativa), white poplar (Populus alba) and eucalyptus (Eucaliptis camaldulensis).

Thorny cornflower

The spiny cornflower, Centaurea horrida, is certainly the plant species of greatest naturalistic importance on the Island, and because of its phytogeographic and scientific interest it attracts many botanists from all over Europe.

The importance of this paleoendemic exclusive to the Sardinian flora lies in its “genetic distance” from other species in the genus, a kind of living fossil.

The scientific name recalls its particularly spiny and bristly morphology, an adaptation to the extreme ecological conditions in which the species lives. The plant forms pulvini with a characteristic ash-gray color that lend an appearance of uniqueness to the Asinara coastal garrigue landscape.

Another frequently associated species of great interest is the astragalus, Astragalus terracianus, which differs from the spiny cornflower in its bright green color.

The area of Asinara where it is easiest to observe this species is along the high and steep coasts near Punta Sa Nave.

Euphorbia

On the Island, the plant landscape is dominated by thermophilic Mediterranean scrub, which takes on different characters depending on the characteristic species. One of the most conspicuous is the tree spurge (Euphorbia dendroides) particularly in the spring months when it takes on distinctive colors, from green to red.

Euphorbia is a species-rich genus located in all parts of the world with warm climates, and the acrid milky juice is characteristic. The flowers are small, green in color and grouped in inflorescences.

E. dendroides is a hardy, woody plant with many branching stems to form large bushes that can exceed 2 m in height. The stem is reddish and scarred by the scars of fallen leaves.

Phoenician juniper

Juniperus phoenicea (Juniperus phoenicea), a member of the Cupressaceae family, occurs as a small evergreen tree or shrub with stout twigs covered with small, scaly leaves.

The globular fruits are arranged near the apex of the twigs, which take on a dark red color when ripe.

It is a very long-lived tree characterized by slow growth; because of the low putrescibility of the trunk and the distinctive scent of the wood, it has always been highly sought after for construction. On Asinara Island, even in recent decades, many specimens of this plant have been cut and harvested to be later processed for floor joists.

Junipers still in an excellent state of preservation are present in Sant’Andrea, near the Campu Perdu Ossuary and, on sand, near Cala Arena, while isolated individuals are present in the Castellaccio area, Cala d’Oliva, Punta Sabina and Punta dello Scorno.

Fauna

The fauna has also undergone profound changes in recent decades. Historical sources report the presence of species important from a naturalistic point of view, such as the mouflon, Sardinian deer, monk seal, and osprey.

More than 80 species of terrestrial vertebrates belonging to the classes of Amphibians, Reptiles, Birds and Mammals are reported on the island today. However, the number does not provide an idea of the island’s international importance for wildlife conservation and reproduction, which includes several rare and endangered species.

Endemic entities may include the luscengola, a curious scaly reptile, the Sardinian hare and the reddish crocidura, small reducers; among the Sardinian-corse species, the small dwarf algiroid lizard, the Sardinian barn owl, the wren, the flycatcher and the black bunting, in the Sardinian subspecies, the quercino and the muflone.

In terms of their conservation status, they can be reported:

– three vulnerable species: stormbird, Corsican gull and common tern;

– Two species with indeterminate status: greater and lesser berta;

– seven rare species: mouflon, dwarf algiroid, Sardinian hare, common tortoise, tarantolin, peregrine falcon, tufted cormorant;

– three insufficiently known: Sardinian discoglossus, Sardinian partridge and magpie.

Invertebrates

To this group belong completely different animals that are little considered due to their small size and yet are of great scientific and biogeographical interest. A review of their knowledge on the island was made during the park’s Second Environmental Education Week at a work shop on the island’s biodiversity; on this occasion, a first check list of insects was presented by the Institute of Entomology of the University of Sassari, with more than 500 species surveyed, including some of relevant scientific interest such as the Sardinian endemics Orthetrum trinacria, Zigaena carsica, Lasiommata tigelius, Halopyga sardoa, Carabus genei, Libelloides carsicus, or even the endemics exclusive to Asinara, Typhloreicheia arganoi, Pseudomeira sinuariae and Trachyphloeus belloi.

Also among the invertebrates, mention should be made of the research on meiofauna conducted by the University of Viterbo, which highlighted several genera and species belonging to the group of Harpaticoids, exclusive to particular environments on the island, such as the sands of Cala Arena, and the studies on Platelminths carried out by the University of Sassari, also with taxonomic entities that are interesting from a biogeographical point of view.

Amphibians and Reptiles

Amphibians include three species belonging to the anuran order: tree frog (Hyla sarda), discoglossus (Discoglossus sardus) and emerald toad (Bufo viridis), found at fountains and water reservoirs.

Among reptiles, 12 species have been reported, including: the common tortoise (Testudo hermanni), the Greek tortoise (Testudo graeca), the Turkish hemidactyl (Hemydactilus turcicus), the tiliguerta lizard (Podaricis tiliguerta), the coluber (Coluber viridiflavus) and the viperine snake (Natrix maura).

A study is currently being conducted by the University of Florence to learn about the distributional status of herpetofauna at Asinara and possible damage due to predators (wild boar, laridae and corvids).

Birds

They are among the best-known animals on the island and have been studied for more than 15 years, with colony censuses and ringing to study migratory flow. Since 1998 Asinara has been included in the project called Small Islands coordinated by the National Institute for Wildlife, whose main purpose is to study the spring migration of trans-Saharan passerines.

About 150 species (half belonging to the passerine order) were observed, of which 52 were found to be breeding.

As many as 80 species are of European conservation interest: 2 are found to be of global concern (kestrel hawk and Corsican gull); 13 are threatened, vulnerable or rare (greater sage-grouse, gannet, queen’s hawk, redshank, nightjar, sea jay, woodlark, redstart, magnanina, grey shrike, red-backed shrike and ortolan); 31 species have strictly European range (e.g. osprey, kestrel, cuckoo hawk, peregrine falcon, Sardinian partridge, barn owl and little owl); 38 a favorable conservation status (e.g., tufted marangon, honey buzzard, robin, Sardinian magnanina, little tern and Sardinian warbler).

An introduced species, not found in Sardinia, is the magpie (Pica pica), brought by some prisoners and bred as a pet. Today it is well adapted to the island’s conditions and its presence is a disturbance to other bird species.

Mammals

As for Mammals, there are 11 species, accounting for about 60 percent of the total Sardinian species: 3 insectivores (hedgehog, reddish crocidura and mustiolus), 1 lagomorph (Sardinian hare), 5 rodents (quercine mouse, wild mouse, black rat, brown rat, house mouse) and 2 ungulates (wild boar and mouflon).

Mouflons were introduced in the 1950s from the Capo Figari colony in Gallura. The lack of predators and some form of protection have allowed the animals to reproduce until they have reached a substantial population that lives mainly in the Fornelli-Tumbarino and Punta Scomunica area and represents a possible reservoir for repopulation in other areas of Sardinia.

The wild boar was reintroduced around the 1960s starting with a pair from the Cossoine area in the province of Sassari. Wild boar has been breeding consistently due to the lack of natural predators and its prolificacy. It is also likely that other introductions were made with animals of non-Sardinian origin and crosses with domestic pigs, raised in the wild and semi-wild state. The impact of these animals is documented on the soil by the characteristic furrows, made in search of food. The Park, in cooperation with the National Wildlife Institute, has initiated actions aimed at controlling the numbers of these ungulates.

Other species with a strong impact on vegetation are domestic species, especially goats. Numerous wild individuals are found throughout the island, including the most inaccessible cliffs on the western side. Cattle, sheep, pigs and horses are also present. During the prison years, the number of heads was far higher than today, fluctuating widely depending on the type of activity within the island but often around 5,000 heads, clearly too many compared to the potential of the soil and vegetation.

Other species include donkeys, the Sardinian gray donkey and the characteristic white Asinara donkey.

The white donkey (Equus asinus var. albina) is characterized by small size, which in an adult individual is about 1 m tall at the withers. It has a quadrangular head with a straight profile, short neck, strong limbs, and a small, white foot. They exhibit marked photophobia and an unsteady gait in bright environments.

The originality of the animal is due to the characteristic phenotype manifested by white coat coloration, pink skin color, and partial pigmentation of the iris, which is perceived to be pinkish-white.

The term albinism is defined as an inherited alteration in melanin metabolism characterized by the decrease or absence of this pigment in areas where it is normally present. This is a genetically determined enzymatic defect that causes a blockage of melanin biosynthesis by melanocytes, which are otherwise present in normal numbers.

During growth, the hairs from a shiny-white color and cottony appearance in the first months of life, tend to a white-opaque color with a bristly texture.

The origin of these animals has not yet been defined with certainty: perhaps they are specimens derived from white donkeys imported from Egypt in the last century by the Marquis of Mores, Duke of Asinara; a more suggestive legend sees them landing on the island following the shipwreck of a vessel bound for France; however, the most probable hypothesis would seem to be that of an autochthonous origin, according to which white donkeys are derived from gray ones by the appearance of the character of albinism.

The number of individuals currently present on the island is estimated at about 120 individuals, divided between the two sexes, to which must be added a few dozen individuals distributed in Sardinia (Foresta Burgos, Le Prigionette, Is Arenas) and the peninsula (Poppi and Collazzone). The recent censuses carried out by the Park Authority represent the highest quantitative data in decades (literature on the subject shows values always between 50 and 70 individuals), and it is very likely that the white donkey population can only grow in the future.

The reduced gene pool and marked inbreeding, however, have consequences for reproduction, with low fertility in broodmares and a general susceptibility to erythema and dermatitis, localized mainly on the neck and ears, especially following fight bites.

The Park, in order to conserve the genetic heritage of this species, has entered into two specific agreements, with the Forestry Authority of Sardinia and with the Faculty of Veterinary Medicine of Sassari, through which constant monitoring of the health status of the animals is guaranteed.