Sečovlje salt-pans are best known for their birds which, however, are far from being the only salina inhabitants.
Sečovlje salt-pans are home to several small animals that are not known to occur anywhere else in our country. The shallow salty water is inhabited by numerous bristleworms, crustaceans, bivalves, larvae of certain fly species and a whole array of beings that happen to be inviting food for birds. The area of the pans is also home to few bee species that cannot be found elsewhere in Slovenia. The halophilous plants in the pans host several species of plant-eating bugs. Reeds are inhabited by the extraordinary Spider Cicadas (Caliscelis wallengreni) and Short-winged Slender Bugs (Dimorphopterus blissoides). On the wet salina mud, Shore Bugs (Halosalda lateralis) can often be seen running to and fro.
For permanent inhabitants that spend the greater part of their lives on more or less bare and salty ground, the Sečovlje salt-pans are not a particularly hospitable place. Here, the small mammals, in contrast to their bigger relatives, cannot avoid a whole series of troubles. The pans are home to the Lesser White-toothed Shrew
(Crocidura suaveolens), East European Hedgehog (Erinaceus concolor), Wood Mouse (Apodemus sylvaticus), House Mouse (Mus domesticus), Harvest Mouse (Micromys minutus), Black Rat (Rattus rattus) and Etruscan Shrew (Suncus etruscus), and some rare bat species have also been recorded in them. Traces in the soft salina mud speak that wild boars, deer, badgers and foxes live here, too. In the Sečovlje pans, reptile species are scarce. Best represented among lizards is the Italian Wall Lizard (Podarcis sicula campestris), which can be found on the levees and among the ruins of the former salt-pan houses. Quite common here, as far as snakes are concerned, are merely the Whip Snake (Hierophis viridiflavus carbonarius), Aesculapian Snake (Elaphe longissima) and Dice Snake (Natrix tesselata), although the rare Four-lined Snake (Elaphe quatuorlineata) has been found here as well.
On the banks of Dragonja River and in the freshwater marsh along the area of Rudnik at Sečovlje, the European Pond Terrapin (Emys orbicularis) can be observed.
In actual fact, there are no amphibians in the salt-pans, this very unfavourable living environment as far as these smooth-skinned vertebrates are concerned. Individual Common Toads (Bufo bufo), Agile Frogs (Rana dalmatina) and European Tree Frogs (Hyla arborea) can be found only at the salt-pans' margins – along the airport and at Stojbe, where Smooth Newt (Triturus vulgaris) lives as well.
The characteristic species of the salt-pan fields is the Brine Shrimp (Artemia parthenogenetica), no more than a centimetre large bright red type of plankton. Well adapted to the high salinity of water in the basins is also the Tooth Carp (Aphanius fasciatus). Quite common in these waters are the Littoral Crab (Carcinus aestuarii) and the Mediterranean Mud Shrimp (Upogebia pusilla). The numerous channels, which are linked with the sea and therefore good food suppliers, host hundreds of European Seabass and Gilthead Bream which, however, are far from being the only fish species here. The Sečovlje salt-pans' water basins and channels are also rich with molluscs and other invertebrates.
In the summer months, the natural salt lakes, salt-pan basins in which salt is made from seawater, and other salty environments often bathe in bright red-orange colours created by the numerous microorganisms that have adapted to the life in very salty environments. They are an important part of the ecosystem of these environments, as they are the basis of the food chain in them. The diverse world of microorganisms that is revealed to us only when looking at it through a microscope is composed of the simple single-celled archaea bacteria of the family Halobacteriaceae and halophilous eubacteria Salinibacter ruber, single-celled algae such as Dunaliella salina, and multicelled trichal cyanobacteria with predominating Microcoleus chthonoplastes. In spite of the data from literature according to which the environment of Sečovlje salt-pans is too salty for fungi to subsist in it, we can still find them there.