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.
A mature male, member of the genus Sympetrum, found in a dry grassland, close to the coast of Marlera, on a beautiful summer day (29th of August). The temperature was close to 29°C, while the average for this period is around 26°C.
It was a slightly cloudy day in mid-May when I decided to visit the northern part of Istria (Croatia), between Mount Ucka (Fig. 1) and the mountainous plateau of Cicaria, which is an extension of the Dinaric Alps. The area is mostly uninhabited, wild and largely untouched. Flower-rich wheat meadows are dominant here; in the past they were (most probably) pastures. Today they provide habitats for bees, butterflies, grasshoppers, spiders, mammals, reptilians and so on. Among flowers, I recognized Polygala nicaensis, members of the genera Ajuga and Ranunculus, various orchid species and, of course, grasses. Among orchids, I found Orchis puprpurea (Fig. 1 and 2), Orchis tridentata (Fig. 3), the very common and widespread Orchis morio, the delicate Cephalanthera longifolia and the non-photosynthetic Neottia nidus-avis, which prefers shady places along the nearby deciduous woodland.
Given the altitude and the higher soil moisture level, the plant communities present here are the typical sub-mediterranean ones. Therefore, I had the pleasure to meet some butterfly species for the first time, one of those meriting a special attention: Everes alcetas (Fig. 4) or the Provencal short-tailed blue. It is a member of the Lycaenidae family which, although occuring sporadically, it is common across the central Europe.
In general, they feed on plants of the genus Medicago, Coronilla varia and Galega officinalis where they lay their eggs. They prefer bushy and sunny places but in Istria are very local and spotted by me only in this location.
One butterfly species that I encountered in the same area is the marsh fritillary (Euphydryas aurinia), a member of the Nymphalidae family (FIg. 5 and 6). This species is in decline in Europe, and is protected under law in the United Kingdom. However I managed to see them quite abundantly in many sites around Istria; perhaps because their habitat – the damp heathy grasslands – is still pretty intact in this region.
This is a widespread species, present in the central and southern Europe. However, it is very local and in Istria I found it only here. Larvae feed on members of the Aristolochia genus and in some areas, for instance in Hungary, it is restricted to only one Aristolochia species: the Birthwort (Aristolochia clematitis). The wings are yellow, a bit paler in females, covered with a gaudy pattern of several black bands and spots, with a distinctive black sinuous line at the margin. On the edge of the hindwings there are several blue and red warning spots. The body is black, with red warning spots at the side.
A very common species of this region, and easily found hidden between flower petals:Thomisus onustus (Fig. 1) is a crab spider known also as the flower spider. In fact, this species and other members of theThomisidae family don’t build a web – instead they wait hidden and camouflaged on flowers for a prey to come. When a flower-visiting prey arrives, they grab it with the long front pairs of legs and paralyse it with a venomous bite.
Females can change their colours according to the surroundings. They can be white, yellow or pink and the colour can change in couple of days so that it perfectly mimics the colour of the host flower (Fig. 2). Males are always brownish and never change their colour (Fig. 3).
Another member of the Thomisidae family, Synema globosum (Fig. 4), is also called Napoleon spider because of the black drawing that resembles the silhouette of Napoleon. Found on dry grasslands or forest edges in warm areas, often on red and yellow flowering plants (mostly members of the Apiaceae or Asteraceae family).
Light green hairy spider that can be found on hairy vegetation. This picture (Fig. 5) enables only to determine the genus, Heriaeus. To discern the species it is necessary to look at the dorsal drawings of the opisthosoma and sometimes even the genitals.
Spring days in the Mediterranean region in May are ideal for observing butterflies and other insects, because during this period most of the plants are in full blossom. Therefore, I try not to miss any potential day for wandering with my dog in search of opportunities for a good picture. During one of these sunny and warm days of May, while trekking on Marlera, I spotted a beautiful sample of Glaucopsyche alexis or, Green-underside Blue, a member of the Lycaenidae family. It was resting on a herbaceous plant, most probably of the Linum genus. However, their life history is accomplished on several members of the Fabaceae family and the larvae are attended by various ant species, as typical for this family of butterflies. This species is widespread and common in many European regions, and it can be easily recognised by the metallic greenish-blue flush on the light-grey hind underside wing. In the specimen on the picture (Photo 1 and 2) it is extended to the edge but in some populations it can be reduced.
Eggs are laid on a flower which will later be eaten by the larvae. The colour of the larvae is variable and depends on the colour of the flower they feed on. It can be greenish, dusky-pink or even bright yellow if they consumed the yellow flowers of Spartium junceum.
Larvae is whitish prior the pupation and at this stage it is attended by various ant species (Lasius, Formica, Myrmica, Camponotus etc.).