Last year in this period, while walking on a rocky pasture near Ustrine, a small village of the Cres island that faces the western side of the island, in search for the Mediterranean black widow spider (Latrodectus tredecimguttatus), the entomologist Nediljko Landeka and the botanist Slavko Brana spotted here for the first time the endemic species Iris adriatica (Fig.1).
Described for the first time in 1980 by Trinjastic & al. but, it has been validly published only in 2002, with the scientific name Trinajstić ex Mitić. Since then, this endemic species has been found only in the Dalmatian region around the cities of Zadar, Sibenik, Split, Drnis and Unesic and on the islands of Ciovo, Brac, Kornati and Vir.
Iris adriatica´s flowers can be found in early spring (March-April) in mediterranean and sub-mediterranean meadows, within the “Stipo-Salvietum officinals” (a mixture of Stipa grasses and Salvia officinalis) and the “Festuco-Koelerietum splendentis” (a mixture of Festucaand Koeleria splendens grasses) associations as well as in rocky pastures.
Description: Dwarf, rhizomatous plant, perennial but usually leafless in winter. The stem is short (3-5 cm) and the leaves narrow, straight, sometimes sickle shaped, up to 10 cm long, and 0.5-1 cm wide. The flowers, solitary and large at the top of the stem, can be yellow, purple or violet.
Conservation status: Listed as near threatened in the Flora Croatica Red Book. The wild population is decreasing due to succession of the vegetation – the overgrowth of more dominant species (shrubs) due to the reduced utilisation.
The island of Cres (Fig. 1) lies in the Kvarner Gulf, at the Croatian side of the Adriatic sea. Along with Krk, it is the largest Croatian island – both have an area of about 406 km2 . Rich in biodiversity, it hosts about 1300 plant species, many bird and reptilian species, among them various endangered and protected, of which many endemisms.
Tramuntana is the name given to the northern half of Cres; it is also known as the “head of the island” (or, in Latin, “Caput Insulae”). Situated just slightly above the 45th parallel, Tramuntana is widely covered by a dense forest of deciduous trees such as oaks (Quercus pubescens, Qurcus cerris), ashes, hornbeams, elks and chestnuts. Such abundance of trees is favoured by the peculiar climatic conditions, a mixture of continental and Mediterranean – known also as the submediterranean climate.
This area was once mainly used as a pasture and this activity had an important impact in the architecture of the landscape and in the creation of new components of the ecosystem with peculiar microclimates that enriched the primary biodiversity. The inhabitants of Tramuntana practiced agriculture, raised olive trees and forest harvesting in a sustainable way, which ensured an adequate balance between plant and animal species. Sheep (Fig. 2) were important members of the ecosystem because they ensured the maintenance of the grassland in a natural way, and their carcasses were an important food source for the griffon vulture (Gyps fulvus), which inhabits the nearby cliffs. In the last few decades, the amount of sheep drastically decreased, and this led to the decrease of the number of griffon vultures in the island, since sheep are a crucial component of their food chain.
In the same time, the abandonment of the practice of sheep breeding has caused many changes in the vegetation landscape, since the absence of the grazers has allowed the regrowth of the underbrush, made prevalently of Juniperus oxycedrus, Paliurus spina-christi and Crataegus monogyna.
The interior of Tramuntana is mainly covered by forests, however it is possible to see many scattered open patches with small ponds that are an important source of water for the wildlife; there are also many small areas delimited by dry walls where olive trees and old fruit trees still grow; these are excellent pastures for sheep (Fig. 3 and 4).
What caugt my attention is the strong scent that in the whole island begins to spread starting from March, that is released by a big euphorbian species which starts to flower in this period, the Euphorbia characias subsp. Wulfenii (Fig. 5). Typical of the Mediterranean vegetation, this plant can grow up to 180 cm in height. Even though their flowers attract various insect species (Fig. 6 and 7), like all the members of the Euphorbia species, they produce a toxic white sticky sap, which has been used for treating skin excrescences since ancient times.
The following pictures (Fig. 8, 9, and 11) are just an example of the rich biodiversity of Tramuntana. Starting from early spring, a rich bird concert makes a journey in the area particulary pleasent. The forest is espeically rich in song bird species, owls, the hoopoe, the european nightjar, swifts etc. According to curren estimates, of the 136 bird species present in the island of Cres, 65 of them nest in this area. In the whole island there are 32 autochtonous amphibian and reptilian species, among them the common toad (Bufo bufo), the blue-throated keeled lizard (Algyroides nigropunctatus), the common newt (Triturus vulgaris meridionalis), the yellow-bellied toad (Bombina variegata), the agile frog (Rana dalmatina) and the slow worm (Anguis fragilis). One curios thing is that, in the island of Cres and Losinj there are no venomous snakes and still nobody knows the exact reason.