SEČOVLJE SALINA NATURE PARK
With its surface area of approximately 700 ha, the Sečovlje Salina Nature Park is situated in the south-westernmost part of Slovenia, along the border with the Republic of Croatia in the southern part of the Municipality of Piran. The northern part of the Park with the still active salt production is called Lera. From the southern part of the Park, called Fontanigge, it is separated by the Grande Canal.
The salt pans of Sečovlje are part of the Nature Park. In the north, they border on the St. Bartholomew Canal. In the east, the majority of the border runs alongside the former narrow-gauge railway, while in the south it is bordered by the St. Odoric Canal, through which the River Dragonja flows today after having been redirected into the canal years ago. In the west, the pans are protected by the levees in the Bay of Piran.
The Lera area is divided into the crystallization area and the seawater condensation area. Lera features typical habitats of animal and plant species limited to the salt fields with various salinity levels, salt-pan canals, and levees.
Fontanigge is located between the Grande Canal and the River Dragonja. In the west, it is bordered by a high-water levee, and by farmland in the east. Fontanigge features a network of canals that used to serve as a seawater inflow for individual salt fields as well as an outflow for wastewater and precipitation water, and as transport waterways.
In SSNP, three key aspects of the usage of space are intertwined: environmental protection, culture and economy with its three industries: salt panning, visiting, recreation, and other supplementary activities. The Government of the Republic of Slovenia has adopted the Decree on the Sečovlje Salina Nature Park in order to protect the natural area and biodiversity of the typical salt pan ecosystem.
Flora and fauna of the salt pans
The salt pans of Sečovlje were created on the alluvial sediments of the River Dragonja and are man-made. With hundreds of years of altering the former mouth of the River Dragonja and converting the surface into salt fields, which also meant the beginning of salt panning, the living conditions here were pretty similar; however, they started changing after the salt making activities ceased. The once vast water surface areas have completely dried out in some places, numerous halophytes started growing in the semi-dry and dry pools, and the species composition of organisms, including birds, started to change.
Salt pans with high salinity level are characterized by salt-loving plants or halophytes. Typically, they are found in the vicinity of river mouths into the sea and in salt pans, but also directly along the coast in the area sprayed by the seawater. Numerous halophytes feature fleshy leaves, they are succulent and their salt content is very high compared to other plants. In autumn, many halophytes acquire red-purple shades of colours.
The salt pans of Sečovlje are particularly famous for their birds. So far, more than 300 different species have been registered, which comes as no surprise since the salt pans represent a large body of water that is used as a feeding and rest area, or wintering grounds during the migration period. Some of them also breed in the salt pans. However, birds are not the only inhabitants of the salt pans. Numerous smaller animals also live in the Sečovlje salt pans’ habitats and many of them cannot be found anywhere else in Slovenia. The shallow saltwater features bristle worms, small crabs, shellfish, fish, larvae of some fly species, and numerous other creatures that often find themselves on the menu of the birds. Also some bee species that can only be found here in Slovenia live in the Sečovlje salt pans.
Salt panning heritage
The cultural heritage of the salt pans of Piran reflects the hundreds of years of the salt workers' life and work on the Adriatic Sea’s northeastern coast. From the many salt pan areas that once existed in the Gulf of Trieste, only those at Sečovlje and Strunjan have survived till this very day, making their importance even greater. It puts them on the level of ethnological, technical, historical, urban, and natural heritage of utmost importance. Salt fields, canals, banks with stone walls, steps and sluice gates, salt workers’ houses with their surroundings, footpaths and transport routes, bridges, pumps, etc. belong to the immobile cultural heritage.
In the 14th century, the cultivation of petola, an artificially cultivated crust comprised of cyanobacteria and other bacteria types, gypsum, carbonate minerals and also clay to a lesser extent, began in the crystallization ponds of the salt fields. Petola prevents salt to be mixed with the mud, but it also acts as a biological filter. At Lera, salt is produced in accordance with the medieval traditions, however, the salt making process was substantially modernized by the Austrians in 1904, when they modified the area by combining several crystallization fields in the centre of the salt pans into a single unit surrounded by ponds of various condensation levels.
In the Fontanigge area, salt production was abandoned in the 1960s, however, within the framework of the activities carried out by the Salt-making Museum, salt making in accordance with the medieval methods is still being demonstrated. Each saline field used to represent a separate salt-pan with its own ponds for seawater condensation and crystallization. The Museum encompasses a group of buildings that used to serve as the residences of the salt workers’ families and as salt warehouses.
BIRDS
So far, 309 bird species have been established at the Sečovlje salt-pans. And why can we find so many different birds here? The salt-pans constitute a large water body, which the birds use as their roosting site or wintering grounds.
When water bodies began to be cleared due to the ever-increasing urbanisation in Slovene Istria as well as in the Mediterranean in general, the Sečovlje salt-pans began to gain, through years, on their significance as a bird sanctuary. A great role in this respect has also been played by the abandoned salt-making in the southern half of the pans. The salters indeed stopped gathering salt there, but they still maintained the levees, regulated the water level in salt basins and thus conserved the different natural living environments. An important role has also been played by the processes of natural forces, which formed a series of similar but different enough environments, which have been eventually inhabited by birds with different dietary and breeding demands. Seawater, which runs deep into the pans through salt-pan channels, brings to the basins large amounts of food that can be easily reached by birds in the shallow basins of the abandoned part of the pans. These are primarily planktonic organisms, tiny invertebrates, and fry. In springtime the pans, which are a widened boundary between the land and the sea as far as birds are concerned, become an important nest-site for numerous birds.
For at least two bird species this is their only nest-site in Slovenia, but there are also several local breeders, which are otherwise known to nest only at a couple of other sites within the country.
The Sečovlje salt-pans play, however, even more important role in the wintering and migration of birds. As they are situated on the Mediterranean coast with its characteristic sub-Mediterranean climate and mild winters, they are highly inviting for numerous winter residents from northerly regions and at the same time constitute the natural habitat, which is truly unique at the national level. The overwintering and migrating bird species are here most numerous as far as the Slovene coast and Slovenia in general are concerned.
The data on breeding distribution, abundance and phenology of birds occurring in the area of Sečovlje Salina (1878-2009) have been contributed by a large number of ornithologists and observers. All published data as well as numerous still unpublished records from personal ornithological notebooks have been gathered. Some of the data, however, have not been accessible, in spite of doing our best to obtain them.
From the area under consideration, a multitude of data from the wintering period (from November to March), spring migration period (March-May), breeding period (May-July), post-breeding period (July and August) and autumn migration period (September-November) was gathered for the wider 1973-2009 period. Data covering the 1983-2002 period have been collected more or less systematically, while those concerning the 2004-2009 period are the result of a regular weekly bird monitoring carried out in the area within the framework of Sečovlje Salina Nature Park's management.
In the 1983-2009 period, a total of more than 1,500 fieldwork days were conducted. 16,800 faunistic data were collected (datum = record on a certain species in a certain place at a certain time), which speak of 751,102 observed individuals. In this contribution, we are dealing with 292 species, which were registered at least once in the area of Sečovlje Salina during the 1870-2009 period. 39 of them are random species, with the data for 9 of them originating from the end of the 19th century (historical records); for 7 species among the latter, a very little chance exists that they would ever occur here again. One species is a wild domestic bird (domestic pigeon).
The most often observed species in the area of Sečovlje Salina was Little Egret (1,133 observations), followed by the Yellow-legged Gull (1,131 observations) and Mallard (928 observations). The Yellow-legged Gull was the most abundant species (390,608 individuals), followed by the Coot (40,054 individuals) and Barn Swallow (38,207 individuals).
In the area of Sečovlje Salina, a total of 53 species have bred so far, only 24 of them in the salt-pans themselves. 39 species are known to breed regularly, with further 6 species breeding only occasionally.
11 species (Falco tinnunculus, Fulica atra, Actitis hypoleucos*, Otus scops, Athene noctua, Anthus campestris, Phoenicurus ochruros, Saxicola rubetra, Saxicola torquatus, Acrocephalus palustris, Corvus monedula) have ceased to breed in the last 10 years in the area under consideration, while 3 totally new species began to breed here regularly in the same period (Tadorna tadorna, Recurvirostra avosetta, Tringa totanus). The Bee-eater Merops apiaster bred here only in 2005.
We have not succeeded to confirm the breeder status for 4 species (Anas querquedula, Anas clypeata, Ixobrychus minutus, Dryocopus martius). 5 species are nonindigenous (Dendrocygna bicolor, Cygnus atratus, Aix galericulata**, Colinus virginianus, Psittacula krameri).
153 recorded species were overwintering in the area, 123 of them in December and 126 in January. 70 species regularly overwinter in the area of Sečovlje Salina, 30 species do not spend the winter there each year, while 53 species are winter visitors.
Spring passage in the area of Sečovlje Salina takes place predominantly between the end of February and beginning of June. In the 1983-2009 period, 213 species were recorded, while during the autumn migration (which takes place between August and November) in this same period 211 species were registered. Many species stop here both during migration and in the overwintering period. 134 species occur regularly during the migration period.
10 of all registered breeders are species of national significance. These are species that in the area of Sečovlje Salina Nature Park hold 10% or more of the entire national population. i.e.: Shelduck Tadorna tadorna, Black-winged Stilt Himantopus himantopus, Avocet Recurvirostra avosetta, Kentish Plover Charadrius alexandrinus, Redshank Tringa totanus, Yellow-legged Gull Larus michahellis, Little Tern Sternula albifrons, Common Tern Sterna hirundo, Fan-tailed Warbler Cisticola juncidis and Cetti's Warbler Cettia cetti.
No less than 87 of all registered species have been inscribed on the list of birds from Annex I of the Bird Directive and migrating species from Article 4. No less than 30 of them are triggering (qualifying) species, for which SPA sites are stipulated. 29 species can be found on the Red List of Breeding Species.
* It was already Gregori (1976) who referred to the Common Sandpiper as a possible breeder, given that he had observed separate individuals in the breeding season. Škornik et al. (1990) and Makovec et al. (1998), too, cite the Common Sandpiper as a breeder owing to their observations of this species in the breeding season, but they never managed to find its nest. The more recent observations, however indicate that in all likelihood we can delete Common Sandpiper from the list of Sečovlje Salina breeders.
** Although the Mandarin Duck was introduced to Europe as early as in 1740, some sources still refer to it as a nonindigenous species, while others have included it on their lists as a species that occurs in Europe as a visitor and even breeds in places (BirdLife, 2010).