Lakeside

The shores of lakes and ponds are one of the environments identified in the Provincial Nature Reserves.

They are among the most important and valuable wetland environments: in addition to their botanical interest, they are also of interest to fauna, as they are irreplaceable breeding sites for fish, amphibians and birds, resting places and refuges for migratory birds, and habitats for a multitude of invertebrate animals.

Moreover, their vegetation acts as a real water purifier, absorbing nutrients, retaining sediments and enriching the water with oxygen.

In spite of all this, the shores of lakes and ponds are among the ecosystems most affected by man's 'land hunger': the banks are often besieged by the extension of cultivation, the construction of dwellings and buildings of various types, the building of roads and perilacual paths, or transformed into improbable beaches, replacing the typical vegetation with earth or, even worse, unsightly white gravel.

Of the various types of plant communities in wetland environments, that of the shores is perhaps the most conspicuous and easily recognisable. This is particularly true with regard to the reed bed, whose appearance is familiar to everyone as, forming a more or less deep and continuous border around the body of water, it represents one of the typical features of the lake landscape. In the dense curtain of marsh reeds(Phragmites australis) grow thelacustrine fishbone(Schoenoplectus lacustris), the cattail(Typha latifolia) and the greater knapweed(Sparganium erectum); where the water is shallow, also the yellow iris(Iris pseudacorus), water mint(Mentha aquatica) and the small marsh scutellaria(Scutellaria galericulata); the areas where the water gives way to dry land are characterised by the showy tufts of Carex elata. These plants, which live in a 'bridge' environment between water and land, frequently show common adaptations. For example, since the roots have difficulty obtaining the oxygen they need for cellular respiration from water, they are often particularly rich in empty spaces that serve to store this indispensable gas. Moreover, in many cases, bank plants are equipped with underground stems (rhizomes) that crawl through the mud for tens of metres, branching out and giving rise year after year to new roots and aerial stems that emerge from the water. This mechanism leads to the formation of a true network of stems that consolidates the mud and creates a stable base for the growth of other plants, and is therefore the main culprit in the process of silting up lakes and ponds.

When the banks are bordered by a belt of marsh plants, the lake environment becomes suitable for water birds. The vegetation on the banks provides a safe place for these animals to take refuge quickly in case of danger, but also a quiet, sheltered space where they can build their nests and raise their young. The tender shoots of aquatic plants and their leaves are much sought-after food for various birds, such as ducks. The richest source of food, however, is the multitude of small invertebrate animals living in the water and on the banks: adult insects and their larvae, snails, worms, etc.

The shores of the lakes can be home to two species of reptiles, which share the name 'water snakes': the collared snake and the taxidermy snake. These snakes are particularly adept at swimming, spend their lives near water and feed mainly on aquatic prey. They are two species that are completely harmless and very fearful of humans. If disturbed, they flee into the tangle of marsh vegetation or quickly dive into the water.

Lake shores are very important environments for amphibians. In fact, there are numerous species, from frogs to toads to newts, that use lake shores as breeding sites in spring. An almost indispensable condition for this to happen is the presence of a strip of marsh vegetation on the shore itself: in this way, the eggs can be laid in the water between the vegetation, remaining safe from fish and other predators; the tadpoles also benefit from this protected situation, being able to carry out their metamorphosis.

In those stretches where the lake shores have retained their natural vegetation, the shallow water is populated by a wide variety of invertebrate species. In fact, there are numerous insects and other small animals that have an aquatic phase in their life cycle; lakeshore water is preferred because it is shallower, richer in nutrients and warmer. For invertebrates, bank vegetation provides a valuable environment in which they can take refuge and find food.

In lakes, the lakeshore belt is certainly the area where the greatest biological richness is observed, and this can also be seen in fish. Many species live in the water along the banks; of course, the composition of the ichthyofauna also changes greatly depending on the characteristics of the water body. Moving from the warm lakes on the valley floor to the Alpine lakes, the change in environmental characteristics causes an almost total change in the fish species present.