Reclaimed areas

Before reclaimed areas…
The realisation of reclaimed areas
“A” reclaimed area: flora and fauna
“B” reclaimed area: flora and fauna
“D-E” reclaimed area: flora and fauna
Zonation of reclaimed areas

Before reclaimed areas...

After the Second World War the second industrial area of Porto Marghera began to be built. Since then a period of expansion started, which led, in 1960, to the realisation of new structures: the first was the excavation of the canal that links the port of Malamocco to the area of S. Leonardo in Marghera, which allowed oil tankers to enter the industrial area (from Rallo G., “Guida alla natura nella laguna di Venezia – Itinerari, storia e informazioni naturalistiche” ”, 1996).
The realisation of Oil tanker canal caused the cancellation of several important historical traces as San Marco's old embankment, a massive work built between 1534 and 1543 to defend the city from the flooding of the Piave (from Caniato G., “L’organismo delicato: il governo idraulico e ambientale” in “La laguna di Venezia”, 1995).
The building of the first part of this embankment had already begun in 1327 between San Marco in Bocca Lama and Campalto with the aim of diverting the fresh waters of the Bottenigo and of the Muson from the central lagoon.
One more evidence of the Venetian history disappeared because of the realisation of the Oil tanker canal (from Zanetto G., Calzavara A., “La laguna tra residualità e modernizzazione”, in “La laguna di Venezia”, 1995) is represented by the island of San Marco in Bocca Lama where an old church built in 960, later substituted by San Marco's church in 1320, was located. After diverting the Brenta, which threatened the surviving of the island, the activity started again and the island began to represent an important point of reference for those who, after the closing of the inlet of Fusina, were forced to sail through that area of the lagoon.
During the plague of 1348 the island was used as a cemetery for the great number of victims of the epidemic (from “Relitti dalla laguna di Venezia”, articolo reperibile nel sito internet di Assonet, Archeologia Subacquea Speleologia Organizzazione Network; from Masiero F.,“Le isole delle lagune venete – Natura, storia, arte, turismo”, 1981).
Before the Oil tanker canal was realised in the zones where the reclaimed areas are now located there were once saltmarshes and shallows marked by a network of canals.

The "A" reclaimed area: flora and fauna

The "A" reclaimed area is located west of the mainland, near Malcontenta, and it covers a surface of 155 hectares. As it is not linked neither to the lagoon canals nor to other water courses, only rainwater can be found there.
Within this reclaimed area, because of the embankment, a part of the lagoon canal named the Taglio dell'Aversa has been completely isolated by the Lagoon.
The part of the reclaimed area facing the mainland is flat and has a half-submerged vegetation, also influenced by the presence of two rainwater chiari.
The banks are covered with common reed (Phragmites australis), sea rush (Juncus maritimus), and with narrow leaf cattail (Typha angustifolia).
In the internal border there are the tick quackgrass (Thinopyrum pycnanthum), the orchardgrass (Dactylis glomerata) and the french tamarisk (Tamarix gallica).
There are several species of nesting, migratory and wintering water birds distributed in the three main biotopes of the reclaimed area:
· gently sloping surface with more elevated slimy-sandy relieves: kentish plover (Charadrius alexandrinus), little riged plover (Charadrius dubius), greater short-toed lark (Calandrella brachydactyla);
· half-submerged tracts and marginal zones: spotted crake (Porzana porzana), common moorhen (Gallinula chloropus), stilt (Himantopus himantopus);
· embankments and banks of the closed internal canal: little grebe (Podiceps ruficollis ruficollis), little bittern (Ixobrychus minutus), mallard (Anas platyrhynchos), common coot (Fulica atra), cuckoo (Cuculus canorus) (from Rallo G., “Guida alla natura nella laguna di Venezia – Itinerari, storia e informazioni naturalistiche”, 1996; from Calzavara D., “Le casse di colmata della laguna media, a sud di Venezia – VII. Ipotesi per lo studio fitosociologico della cassa D-E”, 1980).

The "B" reclaimed area: flora and fauna

The "B" reclaimed area is located in the middle of the central Lagoon and it can be reached only by boat. It has a surface of 385 hectares.
It is completely covered with re-colonising vegetation: above all with white poplar (Populus alba), the Lombardy poplar (Populus nigra), several species of willows (Salix spp.) and with french tamarisk.
As in the other reclaimed areas, here one can find the glasswort (Salicornia fruticosa), sand couch, common reed and narrow leaf cattail, the last two especially where temporary water ponds and freshwater "chiari" of meteoric origin are present.
Towards the Teneri Lake the stilt, the Montagu's Harrier (Circus pygargus) and the great reed warbler (Acrocephalus arundinaceus) are present among others.
In the wooded area the red-backed shrike (Lanius collurio) and the eurasian penduline-tit (Remiz pendulinus) find the right habitat for nesting (from Rallo G., “Guida alla natura nella laguna di Venezia – Itinerari, storia e informazioni naturalistiche”, 1996; from Calzavara D., “Le casse di colmata della laguna media, a sud di Venezia – VII. Ipotesi per lo studio fitosociologico della cassa D-E”, 1980).

The "D-E" reclaimed area: flora and fauna

The "D-E" is the widest (752 hectares) of all the reclaimed areas and it is characterised by several ecological niches.
Inside of it there are numerous backmarshes made up mainly of rainwater, even if with high tide they can be made of brackish waters too.
It is located in the middle of the central Lagoon.
Its vegetation has evolved towards a less and less halophilous kind of inland flora.
Vegetal groupings are still evolving and cannot be assimilated to associations.
In this reclaimed area too, one can find the narrow leaf cattail, the common reed, the sea rush, the glasswort, the puccinellia (Puccinellia palustris), poplars, french tamarisk and the wigeongrass (Ruppia maritima).
As far as the avifauna is concerned, here, besides the species found in the other environments, some rare species can be seen as the purple heron (Ardea purpurea), which nests in the bed of reeds (from Rallo G., “Guida alla natura nella laguna di Venezia – Itinerari, storia e informazioni naturalistiche”, 1996; from Calzavara D., “Le casse di colmata della laguna media, a sud di Venezia – VII. Ipotesi per lo studio fitosociologico della cassa D-E”, 1980).
In the reclaimed areas the highest salinity is found in the lowest soils, while it decreases at upper levels and it can even disappear in the mesophyll grasslands.
Vegetation is continuously evolving towards less and less halophilous characteristics and this process, slower in the lower parts, has almost come to its conclusion in the upper zones even if in the last few years this trend has been reversed because of the expansion of the lagoon due to the lowering of the coast (positive bradyseism) (from Pignatti S., “La vegetazione alofila della laguna di Venezia”, 1966).

In the "B" and "D-E" reclaimed areas, besides the presence of the avifauna, other animals have been noticed: the grass snake (Natrix natrix) and the nutria (Myocastor coypus), even if not in an elevated number, are present.

Zonation of the reclaimed areas

Depending on the characteristics of the vegetation, each of the reclaimed areas can be divided into three areas:
a) areas scantily involved in the land reclamation works and that have therefore kept their original features, represented by halophilous vegetation and by the presence of "chiari" made of brackish water;
b) wooded areas, in which specimens of poplar, willow-tree, birch are present: these are the most internal and elevated zones;
c) the remaining areas represent the widest zone: the vegetation in these areas is of mesophyll kind (for example Agropyron pungens), while in the most low-lying zones the rush (Juncus sp.) and the common reed (Phragmites australis). Here the "chiari" are characterised by low salinity (< 10%) which allows the development of the bed of reeds.

The reclaimed areas, for their abundance of ornithological species, are considered nationally important biotopes; some specimens of bittern and several individuals of Airone rosso included in the Annex 1 of the EEC directive 79/409 (“Birds Directive ”)live there.