Study area

The cliffs of Duino, and in particular the spectacular path dedicated to the German poet Reiner Maria Rilke, who composed here the famous 'Duineser Elegien', is not only one of the most visited sites in the Trieste Karst, but also a protected area of great naturalistic value. The Regional Nature Reserve of the Falesie di Duino, established by the Regional Law 30.09.1996 n. 42, and managed by the Municipality of Duino Aurisina - Občina Devin Nabrežina, includes a high and steep limestone cliff, a small portion of the Karst plateau, and a marine area for a total surface of 107 hectares. The area, placed at the transition from the Central European to the Mediterranean biogeographical domains, is home to Central European, Illyrian-Balkan and Mediterranean plant and animal species, with a particularly high biodiversity. The Cliffs of Duino are the only station of the endemic Centaurea kartschiana, a plant that grows on the part of the cliffs closest to the sea, and the surrounding areas are home to one of the northernmost relics of Mediterranean scrubland in Europe.
The list of species for this guide largely derives from the floristic database of L. Poldini (0247.II.c quadrant, Fig. 1), plus a selection of the exotic woody species most frequently cultivated in parks and gardens.

The environment of the Reserve
The Reserve has two main areas: the cliffs with rocky walls and scree, and the flat part on the Karst plateau. The two habitats are different both for the climate and for soil conditions. The part of the Reserve on the plateau is colder, as it is exposed to the Bora-wind which blows from east to northeast. The part of the cliffs is instead warmer, as it is exposed to the south towards the sea, and is located downwind. As a result, in the two areas we find different types of vegetation. On the warmer cliffs there is Mediterranean vegetation, while in the flat area there is a pine wood of artificial origin with species of Illyrian-Balkan vegetation which are widespread over the entire Karst Plateau. The transition from one environment to another takes place along the crest of the cliffs, where the Rilke trail has been created. From the trail it is thus possible to observe both types of vegetation, their meeting and mixing. The two habitats are also distinguished by the type of soil. The area of the cliffs is characterized by vertical or inclined rock walls, rocky towers and scree. The soils are poor in water, and suffer a strong summer insolation. The flat part, on the contrary, has more evolved soils that retain more moisture, thanks to the protective action of the black pine leaves. As a consequence, a woodland vegetation has developed here, while on the cliffs there are only a few shrubs alternating with screes scarcely covered by herbaceous vegetation.

The vegetation of the cliffs
The cliffs host a Mediterranean type of wood dominated by the holm oak (Quercus ilex), an evergreen oak of Mediterranean origin, mixed with black hornbeam (Ostrya carpinifolia), a thermophilous deciduous species of Illyrian-Balkan origin. Therefore, this plant association is called holm oak-hornbeam community, and includes both Mediterranean and Illyrian - Balkan plants. It is present on the eastern Adriatic coast, from Greece to the Leme Channel in Istria. From the Leme Channel to the Gulf of Trieste this type of vegetation is missing, and reappears just along the coast of Trieste, from Grignano, near the Castle of Miramare, up to Duino, where it finds the northern limit. The wood present between Grignano and Duino is isolated from the main contingent of this widespread vegetation and is considered a kind of relic island, which has been preserved due to favourable local climatic conditions.
The species of Mediterranean origin grow on the cliffs up to the ridge and, apart from some single holm oaks, do not spread on the plateau, where the climate is too harsh. Besides the holm oak (Quercus ilex), another small tree present on the cliffs is the Phyllirea latifolia, while the shrubs include the terebinth (Pistacia terebinthus) and Paliurus spina-christi. Along the Rilke trail it is easy to encounter Smilax aspera, a climbing Mediterranean plant. Among the Illyrian-Balkan thermophilous species that live in this plant association and which, besides the plateau, also grow on the cliffs are the flowering ash (Fraxinus ornus), the tri-lobed maple (Acer monspessulanum) and the dog cherry (Prunus mahaleb).
Next to the edges of the holm-oak and black hornbeam wood there is a type of vegetation typical of cliffs and scree. The calcareous soil is poor in water and soil, and the strong summer insolation leads to high temperatures. The plants of this habitat have developed adaptations that allow them to survive in these harsh ecological conditions: the leaves are covered with wax or are hairy to protect themselves from high temperatures and insolation, while some plants have succulent leaves to conserve water. Among these plants we mention the kitchen sage (Salvia officinalis), some succulent species of Sedum and Teucrium flavum. A plant that can be seen along the Rilke trail at the end of summer/autumn is the pyramidal bellflower (Campanula pyramidalis), an Illyrian - Balkan species widespread along the eastern coast of the Adriatic Sea, whose stems can even exceed 2 meters. The endemic plant of the Duino Cliffs, the Centaurea kartschiana, is also linked to this environment. A plant is endemic when it is spontaneous only in a given area. Centaurea kartschiana occurs exclusively along a limited stretch of the coast of Trieste. Along the Karst ridge, at he transition from the Mediterranean to the Illyrian-Balkan vegetation, there are some gravelly sites colonised by the hornbeam, the flowering ash, Cotinus coggygria, the dog cherry and some Mediterranean species such as terebinth.

Centaurea kartschiana
Centaurea kartschiana, whose Italian name means “Cornflower of the Karst” has been described for the first time from the coastal stretch between Sistiana and Duino by Giovanni Antonio Scopoli in his Flora Carniolica, published in 1772. It belongs to the Asteraceae family, characterized by small flowers gathered in a flower head. The individual flowers are all tubular. The plant is to 40-50 cm tall, the stem is woody at the base, erect and branched and the pink-purple flowers bloom from June to August. It lives both on the cliffs near the sea, exposed to marine splashes, and in the cracks of the highest limestone rocks above the sea.

The pinewood
The flat part of the Reserve located between the crest of the cliffs and the road nr. 14 is occupied by an extensive artificial pinewood which was planted at the beginning of the 20th century. The pine forest consists mainly of black austrian pine (Pinus nigra), with a few specimens of Aleppo pine (Pinus halepensis). The pine forest is now undergoing ripeness, and some plants are already too old. As the pine trees die, their place is occupied by local tree species, especially holm oak (Quercus ilex) and flowering ash (Fraxinus ornus), which in the meantime have been able to settle and develop thanks to the covering of the pine trees.

The fauna
The fauna of the Reserve is also of considerable interest, due to the presence of ecologically very different environment types. Reptiles, like lizards and snakes, are preferably present in the rocky sites. Terrestrial mammals, such as the squirrel and other rodents, prefer the brushwood and the pinewood, while cetaceans (aquatic mammals) such as the bottlenose dolphin (Tursiops truncatus) or the stenella (Stenella coeruleoalba), have been observed in the sea in front of the Reserve. Birds are present in all areas of the Reserve. More than 150 species have been observed, most of which migrate, which stop in the Reserve to rest and feed. The species of sedentary birds nest on the rocks and in the wood. The most famous species that has successfully nested in the Reserve is the peregrine falcon (Falco peregrinus), included in the Red List of endangered animals and considered vulnerable. The peregrine falcon has nested on the cliffs from 1987 until the mid-nineties. The cliffs are the ideal environment for reptiles, which on the rocks find ample space to warm themselves on the sun, but also many cracks where they can take refuge in case of need. Among the snakes, there are Elaphe longissima, Coluber viridiflavus, and the horn viper (Vipera ammodytes). Among the lizards we can find the wall lizard (Podarcis muralis) and the sicilian lizard (Podarcis sicula). The most common and also most easily observable reptile on the cliffs is the magnificent Algyroides nigropunctatus, a dark brown lizard with small black spots. In the spring, the males have a black back, a turquoise throat and an orange belly. The magnificent algiroid feeds on various invertebrates, especially insects. This species lives only on the coasts of the eastern Adriatic, from NW Greece and the Ionian islands to the river Isonzo and Mt. Sabotino above Gorizia, the western limit of its distribution area.
The warm rocky walls are suitable for the nesting of some species of birds related to the Mediterranean environment. Among these, the solitary sparrow (Monticola solitarius) nests on the cliffs, a bird the size of a blackbird, with a bluish plumage. The song of the male, characteristic and melodic, can be heard in the early morning and late afternoon, when the heat is attenuated. There are other species of birds that nest on the cliffs, but they are less easily observed. Among these are Phoenicurus ochruros and Sylvia melanocephala, a Mediterranean species found here at the northern limit of its distribution range. In the cavities of the rocks the imperial crow (Corvus corax) nests, a bird of bigger size and completely black. In the pine forest there is also the squirrel (Sciurus vulgaris), which feeds the seeds of pine cones of black pine. You do not see it frequently, as it prefers the quieter areas within the Reserve, as evidenced by the remains of pine cones with which it feeds.

The sea
The depth of the sea of the rocky coast of the Reserve is of a few meters. At this modest depth there is a good penetration of sunlight, which allows the growth of many plant species, both algae and higher plants, adapted to life in the sea. There are many benthic animals (that live attached or tied to the seabed) such as sponges, actinias, and molluscs, and many species of benthic fishes, such as those fo the family Blennidae, Gobiidae, and Labridae, and Serranus scriba. The coastal rocky areas are usually visited by good swimmers such as the various species of Sparidae and the sea bass (Dicentrarchus labrax). From the cliffs it is possible to observe some species of birds on the surface of the sea. Among these the most common are the gulls (Larus cachinnans and Larus ridibundus). From autumn to spring we can observe the wintering species, among whom the small Podiceps nigricollis is frequent.

The interactive guide to the flora
One of the initiatives promoted by the Municipal Administration to enhance the Reserve is the creation of an IT tool that allows visitors to walk inside the Reserve, and in particular along the Rilke trail, being able to easily identify plants and flowers by simply holding a tablet or a mobile phone in their hands. This guide is available in different versions: on the web (with two interfaces, one dichotomous, one with a multi-entry query interface), for CD-Rom, in a printable version, and in a version for mobile phones, the latter downloadable through the free application KeyToNature (for both iOS and and Android devices). Thanks to this innovative approach, the guide will allow many to reach the 'true' knowledge of biodiversity, which often arouses curiosity, respect and interest, using an effective and powerful means for the dissemination of the environmental gems of one of the most important biotopes of the Region . The initiative also allows the creation of educational projects for schools of all levels. The guide, which includes 583 between species and subspecies (including some of the woody plants most often cultivated in gardens) is currently available in Italian (including notes to species) and English (without notes).