The design strategy of surrounding one’s residence with a sunken area – and wherever possible maintaining a permanent body of water there – is a common characteristic of building in the history of human communities.

In many floodplains, and especially in certain regions, the construction of specific sites with these features (in Italy usually named motte, literally “mottes”) saw widespread organisational and cultural development, particularly with reference to territorial protection. Still today, the image of a medieval castle’s moat is the quintessential symbol of a fortification built to defend a given place.

Much like humans, many species of fauna live or spend long periods of the year in large groups to guarantee better protection against possible disturbances and/or risk factors. This is the case with many types of herons, which breed in large multi-species colonies (or heronries). Their typical nesting habitat consists of wet forest environments, which are isolated thanks to the presence of water all around. Until recent times, such landscapes were rather common in the vicinity of large watercourses and marshes.

Due to extensive artificial regulation works that have altered natural rivers all over the country in recent decades, these environments have all but disappeared. The lack of these habitats is now considered the most important factor limiting the presence of heron colonies, and therefore the possibility for these birds to reproduce in particular areas. As a result, building new wet forest habitats suitable for herons is a priority from a wildlife conservation perspective, as well as from the point of view of regenerating these important landscapes.

With this artwork, an old, abandoned quarry basin was redesigned to create large islands in the central area that are completely surrounded by deep water. On these isolated patches, wet forest environments have grown year by year. The fact of being isolated is precisely what has guaranteed the success of this intervention, with the establishment, after some years, of a new breeding colony where various species of herons now breed.

Category

Work-site

Area of intervention

Lake Casanuova (11.5 hectares), Renai di Signa (Florence).

The area is located within the Site of Community Importance (SCI), Special Area of Conservation (SAC) and Special Protection Area (SPA) of the Stagni della Piana Fiorentina e Pratese (Natura 2000 code IT5140011).

Status before intervention

Lake in an abandoned gravel pit near the confluence of the River Bisenzio into the River Arno.

Type of intervention

Construction of large canals with mechanical equipment to isolate large portions of land that would become islands. Plantation of aquatic and riparian species to form extensive bands of wet forest environments. Creation of marshes and ponds around the lake.

Work status

Completed (September 2006).
Further interventions carried out and completed in July and August 2022.

Authorities/agencies involved

- L’Isola dei Renai S.p.A.
- Committee for the WWF Oases of the Florence area
- Municipality of Signa

Main bioindicators used to monitor the ecological functionality of the work-site

Herons, with particular reference to cattle egrets (Bubulcus ibis), little egrets (Egretta garzetta), squacco herons (Ardeola ralloides), night herons (Nycticorax nycticorax) and great white egrets (Casmerodius albus).