Life In a Place Where a River Flows Over the Sea he beauty of the Krka River was recognized a long time ago, so now the entire course environment have led to the disappearance of the river is under protection. Apart from the middle reaches, which belong to the of large areas of the climazonal evergreen T Krka National Park, the Public Institution Nature of the Šibenik-Knin County protects community of the holm oak (Quercus ilex). the upper and lower reaches of the.The upper reaches, starting from the source, are protected Holm oak forests have been cleared for as the Significant Landscape ,,Krka River Upper Course’’, and the lower reaches, the widest arable land for centuries and as the main and most peaceful as the Significant Landscape ,,Krka River Lower Course’’ Here, the Krka expands into Prukljan Lake, the second-largest lake in Croatia. At the place where the Krka source of building material.This type of wood River ends its journey and flows over the sea, there is the Significant landscape “Channel - was used for the construction of houses Port”, from the Šibenik Bridge to the end of the St Anthony’s Channel, more precisely to St and other buildings, as well as the famous Nicholas’ Fortress along with the surrounding coastal area. The “Channel - Port” area was Venetian fleet of merchant and military declared protected in 1974 due to its exceptional landscape values as well as for the Aleppo ships, and it was used as an energy source pine forests and to a lesser extent for the holm oak forests. The unique landscape consists for heating, cooking, ceramics, metallurgy, of the submerged estuary of the Krka River with the prominent St Anthony’s Channel, whose etc. Deforestation affected the ecological shores towards the open sea turn into sheltered bays, and towards the mainland they open into a unique panoramic view of the city of Šibenik. This area is also part of the ecological conditions of the area. In order to stop the network Natura 2000 Krka Estuary, due to the presence of various significant habitats: sandy intensive processes of erosion in the 19th bottoms permanently covered by the sea, estuaries, caves and pits closed to the public and century, foresters began the afforestation with flooded or partially flooded sea caves. the Aleppo pine, a pioneer species that can Apart from its aesthetic value and uniqueness, this area is also valuable for its biodiversity (a withstand the most extreme environmental large number of fish, invertebrates, algae and flowering plants) so this relatively small area conditions prevailing in karst areas. Today, reminds us of a living laboratory due to the almost inexhaustible possibilities for interdisciplinary the Aleppo pine forests on the coast are very research, measurements and monitoring. The underwater world of this wonderful landscape is often used for tourism purposes, while in the rich in colors and shapes. It is significant because of the many species of phyto and zooplankton, hinterland afforestation aims to encourage periwinkle and mussel mollusks, wolf and barrel snails, endemic fish such as black-headed soil regeneration on rocky terrains and the shrike and because of sea turtles and dolphins that also like visiting this marine area. return of indigenous climazonal vegetation of On the other side, on land, we are surrounded by a vegetation belt of evergreen holm oak forests the holm oak. The Aleppo pine and other pine (plant community Orno-Quercetum ilicis) in developmental forms from maquis to garrigue and species are traditionally used in the treatment barren rocky ground, the Aleppo pine (Pinus halepensis) and juniper (Juniperus oxycedrus L.). of the respiratory system. Pine essential oil The Aleppo pine is a Mediterranean species of pine of the Latin name Pinus halepensis, which has long been used in lung treatment, and is indigenous to the warmest part of the Adriatic, i.e the southern Adriatic, and it is named its beneficial effects on respiratory organs after the city of Aleppo in Syria. The millennium-old human effects on the Mediterranean have been scientifically proven.
2 3 THE INVISIBLE UNDERWATER WORLD - PLANKTON
The invisible world of the underwater is made up of tiny plant and animal organisms that float freely in the water. Diatoms, dinoflagellates, coccolithophores, ciliates and copepods are just some of the unusual names of this invisible world that form the basis of life in the sea. In addition to being extremely important in the food chain, they are a good indicator of the state of an ecosystem over time because they quickly react to changes in nutrient intake and pollutants in the water. Copepod, Diatom, In addition to unusual names and shapes, these creatures are adorned with some “superpowers” Acartia clausi Amphora sp. such as bioluminescence, flowering and the ability to create biotoxins or switch to “sleep mode” during adverse environmental conditions, and then “turn on” again when favorable conditions return. Along with diatoms, dinoflagellates are the most important representatives of microphytoplankton and occupy an important place in evolution because there are assumptions that they are one of the transitional stages of the plant world to the animal world. In many dinophytes we encounter bioluminescence, so this group is often called luminescent flagellates. The highest number of phytoplankton was recorded in the first 5 meters of depth. There is a zone in the estuary at a depth of 2 to 5 meters where there is a significant difference in salinity. Above this zone, which we call halocline, freshwater planktonic species predominate, whose populations develop in Visovac Lake and enter into the estuary, sinking slightly and accumulating in the same zone. Below this zone, high concentrations of dissolved organic matter were measured, which indicates the death of freshwater plankton in contact with seawater, which points to the fact that the organic matter in this layer originates from phytoplankton. Due to a large amount of plankton in the ecosystem, the amount of filtrates is high - sponges, shellfish, bryozoa, ascidians, etc. Due to its particularity and pronounced stratification of nutrient-rich water, this area is biologically a very productive ecosystem and an important spawning grounds, nurseries and feeding ground Coccolithophore, Diatom, for many organisms. Calciosolenia brasiliensis Biddulphia titiana
4 5 SNAILS AND SHELLFISH
Date shell, Mussels, Noble pen shell, Banded dye-murex, Hexaplex trunculus Lithophaga lithophaga Mytilus galloprovincialis Pinna nobilis
Shellfish Bivalvia( ) and snails (Gastropoda) belong to the Mollusk (Mollusca) phylum, one of the shellfish and snails, requires systematic research, as shellfish habitats and populations in Krka estuary largest, most diverse and extremely important groups of marine organisms. It is estimated that are under increasing anthropogenic pressure. there are about 20,000 species of shellfish in the world. About 360 species of shellfish have been The noble pen shell or fan mussel (Pinna nobilis) is a strictly protected species in Croatia and Europe. found in the Mediterranean Sea, while about 220 species of shellfish live in the eastern part of the It is endemic to the Mediterranean Sea and the largest shellfish in the Mediterranean. Adriatic Sea (Turk, 2011). During the autumn of 2016, a mass extinction of the noble pen shell was recorded on the coast of Spain When we talk about snails (Gastropoda), the banded dye-murex (Hexaplex trunculus), the turbinate (the west coast of the Mediterranean Sea), and since then the same has been recorded in numerous monodont (Phorcus turbinatus) and the common cerithe (Cerithium vulgatum) dominate the area. localities throughout the Mediterranean Sea, including the Adriatic Sea. The exact pathogenesis Estuary of the Krka River is an area of large primary production and is therefore a suitable habitat for of noble pen shell deaths has not been determined. Currently, the progression of deaths is being many shellfish species. The fact that this area is suitable for their growth is evident by the numerous monitored, the causes and extent of deaths are being confirmed, as well as the exclusion of healthy mussel farms (Mytilus galloprovincialis). individuals of periscopes and their genetic material for ex-situ protection, as well as the preparation of possible conservation measures. As an ex-situ conservation measure, separation of healthy pen The most numerous species of the rocky bottom are mussels (Mytilus galloprovincialis) and oysters shells from several populations in the Croatian part of the Adriatic is being carried out, and they are (Ostrea edulis), while the movable, muddy and scaly bottoms are adorned with Noah’s ark shells (Arca kept within enclosed systems of aquariums. Another measure being employed is the cryopreservation noae), Mediterranean scallops (Pecten jacobeus), grooved carpet shells (Tapes decussatus), warty of their genetic material, i.e. using larvae collectors to repopulate or recolonize them in the worst- venuses (Venus verrucosa) and lagoon cockles (Cerastoderma glaucum). The protected bivalves that case scenario - mass extinction and disappearance of the noble pen shell from its natural habitats. inhabit this area are the date shell (Lithophaga lithophaga) and the noble pen shell (Pinna nobilis). Due to the density of mussel settlements (Mytilus galloprovincialis), it has become somewhat of a symbol of Šibenik Bay and the channel. Sustainable management of marine resources, such as
6 7 Turtles are the only reptiles that inhabit the Adriatic Sea as it is one of the stops of their long journeys, which are possible due to extremely effective respiratory MARINE MAMMALS adaptations. All turtles, including sea turtles, breathe LOGGERHEAD with lungs, but unlike their land cousins, they spend only 3-6% of their time breathing air. In other words, SEA TURTLE they can stay underwater between 4 and 7 hours as part of their daily routine without ever depleting all Caretta caretta of their oxygen supply. There are many interesting physiological changes that enable turtles to turn to land exclusively for reproduction. As they are cold-blooded organisms, their body temperature depends on the outside temperature, which makes them difficult to be seen in the winter months. They respond to a drop in temperature by diving down to the seabed, where they hibernate until Bottlenose dolphin, Tursiops truncatus the next period of warm weather. The underwater camera in Martinska Cove often records their arrival and by clicking on the link https://www.sibenik-meteo.com/podvodna-kamera we can at The Mediterranean monk seal (Monachus monachus) and the common dolphin (Delphinus delphis) least virtually socialize with this fascinating animal through real-time images. became extinct from the Adriatic Sea. They are mammals that once inhabited this area, while today the only resident marine mammal of the Adriatic Sea is the bottlenose dolphin (Tursiops truncatus). So far 220-250 bottlenose dolphins have been recorded in the Croatian part of the Adriatic Sea, with about 50 of them in the Šibenik-Knin County area. Scientists are studying percentages of certain age and gender categories in the population. Interestingly, these proportions remain constant within a population and depend upon the species. Changes indicate the presence of a factor that disturbs the balance. People who research marine biology are not the only ones who find the observation of dolphins in the sea pleasurable. The sight of a dolphin leaves no one indifferent, which is why we find ourselves with a smile on our faces, trying to point to where we saw it in order to share the moment with those around us. Today, we can share those moments with a lot more people through the Cro Dolphin smartphone app, which serves to report marine mammal sightings with a map of the exact location. This information is shared with academic institutions that research and protect marine mammals, and in this way you can contribute as well. The bottlenose dolphin got its English name because of the similarity of the shape of its head and an old-fashioned gin bottle. Although it is not its natural habitat, the dolphin often comes to visit to greet all visitors and enjoy with them the natural Loggerhead sea turtle, beauties making part of the channel. Caretta caretta
8 9 PLANTS THAT LOVE SALT
Meadows of glasswort and Sea fennel, Sea lavender, saltwort plants Crithmum maritimum L. Limonium serotinum
On the coastal sea line, we can find specific habitats influenced by the seawater. Some of these habitats (Triglochin barrelieri), endemic marsh garlic (Allium telmatum), long-bracted sedge (Carex extensa) and are in the tidal zone, exposed to constant periodic flooding, and others are beyond the reach of seawater, vulnerable taxa (VU) herbaceous seepweed (Suaeda maritima) and opposite-leaf saltwort (Salsola but exposed to occasional splashing of the waves and air salinity. Apart from the direct influence of soda). The best- preserved part with halophytes is the coast belt along the Jezerina Cove, south of seawater and salinization, the type of substrate also has a decisive influence on the composition and the wooden bridge towards Školjić and all the way to Braničevo Promontory. distribution of coastal plant communities. Along our shores, rocky coastline is the most common, Crithmum maritimum - sea fennel - is one of the most famous halophytes. It is a plant that is also known and in the area of the Šibenik-Knin County, localities with vegetation of muddy marine habitats have by other names as: crithmum, sea dill, St. Peter’s grass, samphire, rock samphire (local names: motar, been recorded. Halophytic vegetation of the muddy coastline is represented in an uninterrupted belt from Škar Cove, across Jezerina Cove and all the way to Braničevo Promontory. While the average salt matar, motrika, šćulac, tušć, obalac). content in the world’s seas is about 3.5%, saltwater plants live with salt concentrations of up to 10%. Halophyte plants can cope with the stress of high levels of salt through a series of adaptations (and To live in such conditions, halophytes had to develop special adaptations. Some halophytes “fight” thus managed to survive), the most interesting being the phenomenon of salt glands, but they cannot against excessive salt concentrations by collecting larger amounts of water (succulence), some get adapt to the stress caused by human hand. rid of their own parts, and some have special salt glands with which they excrete excess salt. Towards the mainland, the halophyte vegetation alternates with terrestrial vegetation, the Aleppo pine forest with mastics (As. Pistacio-Pinetum halepensis). The largest part of the halophytic belt encompasses MAIN MESSAGE a community of glasswort and saltwort (As. Puccinelio festuciformis-Sarcocornietum fruticosae), a much smaller area is occupied by a community of sea lavender and blue wormwood (As. Limonio-Artemisietum Observe the living world around you, do not disturb it, in nature, leave only coerulescentis), while other communities are represented only fragmentarily and cover small surfaces. The mentioned habitats are on the list of endangered habitat types. In Jezerina Cove there are several your footprints behind and take all the wonderful memories with you. valuable species, the most important of which are critically endangered (CR) Barrelieri’s arrowgrass
10 11 PUBLIC INSTITUTION NATURE OF ŠIBENIK-KNIN COUNTY Prilaz tvornici 39 • HR-22000 Šibenik • +385 22 218 462 • [email protected] www.zpv-sibenik.hr • www.kanal-svetog-ante.com