The management of an “unusual” coastal nature reserve: the example of Bosco Nordio, an educational laboratory and treasure trove of biodiversity
The apparently arid and selective environment of the coastal dunes is actually rich in plant and animal species. If this is due, along the coasts, to the rapid evolutionary dynamics of the habitats from the foreshore to the habitats behind the dunes, in the Bosco Nordio Nature Reserve the main factors that come into play are the orography of the land and the freshwater aquifer.
In fact, the dune habitats of Bosco Nordio are located on an ancient coastline at least a thousand years old, which is now about three kilometres from the sea. For this reason, the dunes and their vegetation have practically “fossilized”: the dynamics present on the shorelines, mainly influenced by winds and the salinity gradient, are absent in the territorial context surrounding Bosco Nordio, which has been characterized for many centuries by vast extensions of cultivated lowland areas.
From a vegetation point of view, the Holm Oak wood would be the last stage in the natural evolutionary successions of these ancient coastal environments. But over the years in Bosco Nordio man has influenced these dynamics, delaying them with periodic cutting of the woods and planting of stone pines, aimed at their “cultivation” for the production of pine nuts. These practices, by blocking the expansion of the woodland into the clearings, have allowed the survival of relict patches of dune grassland habitats including grey dunes (2130*) and Mediterranean wet meadows (6420*).
In addition, the great biodiversity of the Reserve is determined by the particularly high water table level, which leads it to emerge, during particularly rainy periods, in some of the lowlands. Thus, from the most depressed interdunal areas to the top of the fossil dunes, in a difference in height of a few metres, there is a very high humidity gradient.
This is already evident in the composition of the woodland which, in the most depressed areas, is differentiated into a Holm Oak woodland (Quercus robur) while, as far as fauna is concerned, a symptomatic presence is that of the Lataste’s Frog (Rana latastei), considered typical of woodland formations that tend to be more humid, such as oak-carpinets.
If the previous management of the forest for productive purposes paradoxically allowed, as mentioned, the conservation of a discrete level of biodiversity, the entry into force of Community directives in the naturalistic field (first and foremost Directive 92/43 “Habitat”) has modified the management aims of Veneto Agricoltura, including actions directly aimed at the conservation of biodiversity.
Thus, in addition to actions aimed at differentiating the structure of the forest, actions are implemented to contain expansion in the clearings of the forest itself, and habitats characterised by shrub juniper vegetation are favoured. In the areas of the Reserve used in the past for agricultural practices, some ponds and other wetlands have been recreated, sometimes only temporarily flooded. These environments have undergone spontaneous recolonisation by many water-related species, including rushes (Juncus effusus), algae of the genus Chara and some hydrophytes, such as Utricularia australis. In consideration of the didactic and educational vocation of the reserve, but also of the opportunity offered by these spaces for the conservation of the flora, seedlings produced and supplied by the Plant Biodiversity Centre of Montecchio Precalcino have been planted in the vicinity of the artificially created wetlands, intended to trigger processes of establishment of hygrophilous habitats. Of particular note are Cladium mariscus (structural species of habitat 7210*), but also rather rare species, such as Plantago altissima and Hibiscus pentacarpos. However, not all the available areas have been “filled” with plants: the conservation of bare microspaces allows the spontaneous establishment of annual species typical of temporarily emerged wetlands, such as the primrose Samolus valerandi. In fact, the vocation of the reserve is not only didactic, but also more widely “demonstrative”: in addition to offering interesting fields of research for students and trainees, it is possible to test and verify here the results of active vegetation management, aimed at maintaining, through a balanced set of actions carried out by the operators of the reserve, including cutting plants, limited removal of plant biomass, modest earthworks and planting of species of interest, a high environmental heterogeneity, a prerequisite for greater biodiversity. Considering that active management should be the guiding principle with which to maintain and increase the conservation status of species and habitats in the biodiversity hotspots of our territory, the reserve can therefore play an important role as an open-air “laboratory”.
An interesting aspect of the conservation and recreation of this habitat variability is the consequent enrichment of the reserve from a landscape point of view. Compared to the uniform appearance of a single wooded area, the presence of different openings and vegetation landscapes offers multiple points of interest to visitors to Bosco Nordio, supplemented by wildlife observatories and panoramic viewpoints makes for a particularly enjoyable visiting experience.