Dry stone walls and small structures

A mosaic of small structures such as dry stone walls, piles of branches, wood, or boulders, tall trees with cavities, natural hedges, or dry meadows contribute fundamentally to promote biodiversity. So many reptiles, insects, mammals and birds depend on varied environments for feeding, nesting, hiding, etc. What kinds of structures can you find in the biodiversity garden?

For centuries, dry stone walls have been built without the use of lime or cement, as support for terracing or as demarcation of meadows and pastures, a job that requires specific skills.

The living conditions for flora and fauna are very difficult in a drywall, so only species that can withstand large temperature variations live in it. The dry stone walls are also home to a variety of plants that have adapted to life among the stones with very little water and soil available.

A typical dry stone wall plant is the Borracine (
Sedum album
). Its name recalls the word “water bottle,” because of the leaves’ peculiarity of retaining water. It is precisely because of this characteristic that it can survive on stones and rocks exposed to high temperatures. It is an evergreen that grows creeping and perennial, turning brown in winter. Instead, the stems with the little white flowers grow only in summer.

Asplenium trichomanes
is a fern that prefers rocks and walls, settling in the small cavities between stones. It is often seen in drywall. Ferns reproduce through the spores they produce and without flowers and seeds. This lack of flowers has often made people fantasize, leaving them puzzled. People’s disbelief went so far that ferns were attributed magical powers.

Butterfly Apollo
Parnassius apollo
Prefers dry biotopes with lean, stony soil. He willingly feeds on the nectar from the scabious and thistles on which he also willingly spends the night there. The caterpillar Instead, it feeds mainly on borracine. In our region it is present from June to September. To maintain this beautiful butterfly, the host plant must be safeguarded. of the caterpillar and ensure sufficient numbers of thistles, scabious and ambrette. A shortage of appropriate nectariferous plants may be a limiting factor.

The Ramarre
Lacerta bilineata
It lives on sunny slopes with rich vegetation of shrubs and dense grasses. It also needs stony structures such as dry stone walls or boulders where to shelter and enjoy the heat accumulated by the stone. In Switzerland it is found mainly in Ticino and Valais, but in inhabited areas it is threatened mainly by cats hunting it. Adult specimens reach an average of 30 cm in length, but can reach up to 40 cm. Its diet consists of insects, spiders and snails.