Plant biodiversity and adaptation to the environment on coastal dunes

Beaches and sand dunes impose extreme conditions on plants that are at the limit of their survival: the constant wind carries salt droplets that encrust them and sand that continually grinds and submerges them, the substrate does not retain moisture and can reach temperatures of 60 °C. Only psammophytes, or sand plants, can survive in these conditions, thanks to special adaptations.

Only psammophytes, or sand plants, can survive in these conditions, thanks to special adaptations.

To protect themselves from the wind, many species are small or grow on the ground, such as fumana (Fumana procumbens). To find and store what little water is available, the maritime vilucchio (Convolvulus soldanella) and the ravastile (Cakile maritima) have deep roots and fleshy leaves where they store water, like desert cacti. To protect itself from the high temperatures, marine alfalfa (Medicago marina) covers itself with a felt of hairs. Species such as sea holly (Eryngium maritimum), juniper (Juniperus communis) and holm oak (Quercus ilex) have stiff, leathery leaves covered with waxes to limit water loss.

Other plants have adapted to being submerged in sand: the prickly sparto (Ammophila arenaria) develops underground stems (rhizomes) whose growth is stimulated by submergence. Thanks to its rhizomes, this species traps grains of sand and allows dunes to form: it is the true "dune engineer".

It is the true "dune engineer";

Beaches and dunes generate and evolve thanks to the balance between the sea currents, which deposit the sand on the beach, the sun, which dries the sand, the wind, which carries it inland, and the plants, which trap it.

The plants that grow on the dune, as well as actively contributing to its construction, as the dune grows, form different communities arranged in bands (zones) parallel to the coastline, along the strong environmental gradients, to form the so-called coastal zoning.

The community closest to the sea is called Cakileto, named after the guide species Cakile maritima. Although small, the plants of the Cakileto dampen the action of the wind and allow the formation of the first accumulations of sand, the 'embryonic dunes'. It is here that the first perennial plants, such as Elymus farctus, grow, triggering the process of dune formation. Behind the Elymus farctus, the "mobile dunes" develop, colonised by Ammophila arenaria, a species that is very resistant to wind and silting up, whose tufts favour the accumulation of sand and react to silting up by growing in height, thus allowing the dune to grow. Behind the Ammofileto there is a protected zone, the "grey dunes".

The protection from the wind and saltiness allows the presence of more species and the formation of a prairie with flowering species, mosses and lichens, the Tortulo-Scabioseto.

The vegetation of the sandy shores reaches its most complex form in the 'fixed dunes'. The more sheltered conditions allow the development of shrub communities, often dominated by the common juniper (Juniperus communis). The Juniper wood consolidates the dune and creates the conditions for the development of the coastal wood, the Lecceta, dominated by Quercus ilex. The coastal woodland has become rare and has often been replaced by reforestation with Mediterranean pines (Pinus pinea, P. pinaster).

 

 


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.


Biodiversity threatened by alien species today

The problem of exotic or alien species is very broad and complex, touching strings that go beyond biology and ecology. But it is the laws of biology and ecology that must guide us in reading this phenomenon.

There are some major differences between the Gardens of Babylon and the invasion processes we have been witnessing in recent decades.

The introduction of species from one continent to another has always existed. Just think of our oldest Italian botanical gardens whose directors travelled the world in search of 'strange' species to cultivate and show; or the orchid or succulent plant collectors willing to pay astronomical amounts of money to own a certain species (often leading to their extinction in their country of origin!).

What has changed profoundly is the scale of the phenomenon, which has grown with the growth of trade between countries, leading to an exponential increase especially in involuntary, uncontrolled introductions. In its century-long history, the Botanical Garden of Padua has introduced perhaps twenty species from other continents. There are currently more than 3,000 alien species in Italy, an increase of 96% over the last 30 years.

The other aspect, profoundly and dramatically changed, is the state of our ecosystems, impoverished and damaged to the limit of survival, by unprecedented anthropic land use. Our natural and semi-natural habitats are often fragmented and reduced to small clusters in a modified landscape that puts great pressure on habitats and their native species.

Many of the species that are introduced do not survive, but others successfully establish themselves in the area where they are introduced, and spread too rapidly, causing serious damage to the original species and ecosystems. These species are referred to as invasive alien species. From an ecological point of view, the arrival of a new species, which has a different evolutionary history from the native species, is potentially a disruptive process for an ecosystem, which can upset all its internal balances. Especially if this occurs in already damaged ecosystems. It has often been shown that the arrival of an alien species leads to the disappearance (extinction) of native species, which in turn leads to a different (often worse) functioning of the ecosystem and the loss of services that a healthy, functioning ecosystem is able to provide.

The phenomenon of alien species introductions represents one of the greatest global threats to biodiversity, with an increasingly significant economic and social impact: in the European Union alone, it is estimated that the impacts caused by these species result in losses of over €12 billion.

It is therefore a phenomenon that must be seen in its entirety and complexity and certainly cannot be assimilated with other migratory processes that involve spheres that are not the domain of biology and ecology.


The effectiveness of mobile dune restoration work at the Vallevecchia site

Dune ecosystems are increasingly threatened by human disturbance and pressure. This causes an alteration of the plant communities and of the balances that regulate the formation of coastal dunes.

The plant component of coastal ecosystems ensures the growth and continuous development of the dune; however, it is the component of dune ecosystems that is most affected by human disturbance. The lack of vegetation caused by disturbance triggers erosion processes that impoverish the structure and functionality of the entire ecosystem.

 

In view of the increasing loss of surface area and the degradation of the remaining areas, ecological restoration measures are an ideal solution for safeguarding the biodiversity of coastal ecosystems. Restoration measures are generally concentrated where anthropogenic pressure has been excessive and the conservation status of the ecosystem is compromised.

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The research work that led to the thesis entitled "Restoration of dune ecosystems using naturalistic engineering techniques - the case of Vallevecchia" made it possible to assess the effectiveness of the restoration work carried out by the LIFE REDUNE project at the Vallevecchia (Caorle) site.

 

In particular, the restoration of the mobile dunes, as an essential component of coastal ecosystems, was carried out in 5 phases: physical reconstruction of the dune profile, stabilization, planting of nuclei of vegetation proper to the habitat, creation of new accesses to the beach with restrictions and signs, monitoring.

Transplanting took place in November 2018; afterwards, the plantings were monitored using the permanent plot technique. Squares of vegetation of 1m by 1m are monitored periodically to assess the survival of the transplanted species and the evolution of the habitat.

Initial analyses identified two distinct groups of plots: plots located in undisturbed neo-dunes and plots located in disturbed neo-dunes (despite the precautionary measures taken at the beginning of the project). The disturbance, due to the large number of tourists at this site and the lack of respect for the rules, has caused plants to fail to take root in some areas of the restoration, with the consequent loss of biodiversity. On the contrary, in the undisturbed areas most of the transplanted species took root, demonstrating strong vitality, given by a remarkable growth of the individuals in terms of height, new shoots or leaves and cover..

Moreover, following the restoration work, and in the absence of disturbance, it was possible to observe the appearance of other species which in turn developed considerably. At the beginning of the project, only four species were recorded, but by the end of the project, 12 species had been monitored. This demonstrates the effectiveness of the restoration work. However, it is very important that the work is not affected by disturbance events, which would nullify the whole goodness of the project and the survival of the ecosystem.

 

Dune ecosystems are among the most ecologically and scenically important in the world and therefore need to be safeguarded..

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References:

"Restoration of dune ecosystems with naturalistic engineering techniques - the case of Vallevecchia" Enrico De Pellegrini, Master thesis in Environmental Sciences, University Cà Foscari Venice

 

 


Reconstructing the Dutch dunes with the European bison

The Zuid-Kennemerland National Park is now the coastal dune area that is home to the bison in the north of the Netherlands..

Until a few years ago, the Zuid-Kennemerland National Park was largely open to the public, with the exception of an area to the south that was kept closed. The closed area was a dynamic dune system, but in the absence of large herbivores and people, the dunes were becoming increasingly vegetated. The vegetation prevented the sand from moving and the dynamic dunes were made sedentary. This triggered the idea of bringing in large herbivores to remove the vegetation and allow the dunes to move freely again.
The European Bison in a Dutch Dune System project (https://rewildingeurope.com/rew-project/european-bison-in-a-dutch-dune-system/) started in 2007 as part of the Rewilding Europe projects (https: // rewildingeurope.com), a pan-European initiative working at the forefront of recreating natural habitats on a European scale.

The pilot project consisted of returning the European bison to an area in Western Europe where it could live naturally (i.e. without additional food supply), together with Konik horses, Highland cattle, fallow deer, roe deer and rabbits, which were already species of animals used for natural grazing throughout the Netherlands.
The project was carried out in an area of coastal dunes where forested areas are intertwined with open grassland and shrubland. The habitat types are semi-open grassland, shrubland, broadleaf and coniferous forests.

 

But why bison?
The rewilding initiative aims to rehabilitate nature: restoring ecosystems and their food chains. European bison are known as keystone species of habitats that engineer great biodiversity.

Noting the invasion of non-native vegetation, the decline of a common food source has been blamed: specialised insects that need patches of open sand to survive. Bison clean the area, scrub the ground, and with this behaviour, throughout the year, create several local sand patches where native pioneer vegetation and insects once again have a chance to proliferate. Dune birds such as the eagle owl, golden oriole and red-backed shrike that were heading for local extinction have now returned.
Since they also bark shrubs and trees and encourage the dispersal of native grasses through their manure, the bison are essentially bringing back the original biodiversity.

 

The area of the Zuid-Kennemerland National Park where the bison now live is the 330 hectare area that was closed to the public in the past. Now, the area is open to the public, with a footpath that runs through the bison enclosure and is open in the winter months, so tourists can walk and hopefully catch a glimpse of these majestic creatures among the rolling hills and dunes.

 

The European bison is one of two living species of bison, the other being the North American bison. Established in the wild in the 1920s, the European bison has returned thanks to conservation programmes across the continent, from a herd of 12 animals kept in captivity. The European bison is one of the two living species of bison.

The European bison in a Dutch dune system project, which officially ended in 2012, provided valuable practical and scientific knowledge on the ecological aspects of bison such as diet composition and habitat use, including in comparison to cattle and horses. It also attracted the attention of the press, which in turn informed the public about the species and promoted the Zuid-Kennemerland National Park as a tourist attraction for nature tourists.

 

Particularly important for European bison conservation programmes is the expansion of the bison area and the natural growth of the herd.
A series of research articles from the Dutch study of a herd of 22 bison living in Kraansvlak, in the 330 hectares of natural dunes and ponds that are part of the Zuid-Kennemerland National Park, further casts doubt on the belief that European bison are forest-dwelling creatures, now offering a more optimistic assessment of the bison's chances of survival in new European environments.
In 2016, two more Dutch bison introduction sites followed the project, after gaining experience in Kraansvlak.
Nature organisations in Sweden, Switzerland and the UK are watching with interest and the knowledge gained is being shared with established projects in Spain, France and Germany.

E se il prossimo passo per la riqualificazione auto-sostenibile dei siti dunali di LIFE REDUNE contemplasse anche la creazione di parchi naturali popolati dai bisonti Europei?

 

Riferimenti:

PROGETTO Bisonti europei in un sistema dunale olandese: https://rewildingeurope.com/rew-project/european-bison-in-a-dutch-dune-system/

https://forpeoplefornature.com/2015/08/07/introducing-bison-in-the-dutch-dunes/

https://www.theguardian.com/environment/2018/may/28/return-of-the-bison-herd-makes-surprising-comeback-on-dutch-coast

https://www.dutchnews.nl/features/2018/02/the-bison-are-back-rewilding-the-dutch-dunes-brings-back-a-mega-beast/

 

 


The delicate balance between tourism and coastal dune pollination networks

The integrity of ecosystems and their ability to withstand future environmental changes worldwide are threatened by human-induced disturbance. Coastal dunes, including beaches, dune cordons
and interdunal wetlands, are considered among the most threatened ecosystems globally. The intense concentration of human activities and mass tourism are leading to the loss and fragmentation of coastal dunes.

 

In addition to this, mass tourism is also considered one of the most important factors in threatening the integrity of the last natural areas. Indeed, the effects of human disturbance have been widely recognised in local changes in species richness, with terrestrial plants and insects being the most affected groups of organisms. In order to prevent the degradation of natural areas, it is essential to understand whether, and under what conditions, tourism can be permitted.

 

In coastal dune ecosystems, animal-mediated pollination has a marked influence on the dynamics and diversity of plant communities. In addition, coastal dunes are a hotspot for a number of pollinator species that are highly specialised for dune habitats (particularly hymenoptera), many of which find sandy sediments a suitable substrate for nesting.

Understanding the relationship between species from two different trophic levels, which influence each other, is of great importance for the conservation of their populations and for maintaining the resilience of ecosystems over time.
Nowadays, the pollination process is increasingly threatened by human-induced extinction of plant and animal species due to the same factors that threaten the conservation of coastal dune ecosystems: land-use change, habitat loss and fragmentation, and invasions of non-native plants and animals.

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Pollination networks represent the structure of the ecological community and describe the interactions between species, offering the opportunity for a holistic assessment of ecosystem structure and functioning. .

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Dr. Edy Fantinato of the University of Venice Cà Foscari, coordinating partner of the Life Redune project, addressed the issue of assessing the impact of tourism on the structure and resilience of pollination networks in coastal ecosystems (1). The study was conducted on the North Adriatic coast, in seven sampling sites freely accessible to tourists and with different levels of tourist pressure: three at Vallevecchia, two at Laguna del Mort and two at the Cavallino Peninsula.

Pollination interactions were recorded and analysed in correlation with human disturbance descriptors along transects from sea to inland. In total, 1173 interactions between 29 plant species and 173 pollinator species were recorded and three of the most informative descriptors of human disturbance on coastal dune ecosystems were measured: path density, range connectivity of land cover types intercepted by each transect based on the detailed habitat map (produced within the Life Redune project) and the relative abundance of alien floral displays.

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The study revealed that in addition to species richness, human disturbance also affects the structure and resilience of coastal dune pollination networks.

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Focusing on pollination interactions, the study showed that intense human disturbance can significantly influence both the structure and functioning of coastal dune ecosystems, causing local extinctions of plant and pollinator species and simplifying pollination networks.

 

However, the results indicate that moderate human disturbance could have positive effects on coastal dune pollination networks. A moderate level of human disturbance was positively correlated with plant and pollinator species richness. This result is not surprising, as it is not the human disturbance itself that is positive, but the rejuvenating effect it could have on local communities.
rejuvenating effect it could have on local communities. Indeed, moderate disturbance could help to increase the diversity of microsites and create suitable habitats for soil-nesting pollinators.
In addition to species richness, the resilience of pollination networks was also found to be highest at moderate disturbance.

 

In conclusion, evidence emerges that moderate disturbance and long-term conservation of coastal dune pollination networks can coexist.

 

However, in order to achieve this goal, tourism should be regulated and visitor access to coastal sites managed, so as to prevent human disturbance from compromising both the structure and functionality of coastal dune ecosystems.


Drones and GIS database to monitor anthropogenic threats to dunes

The general objectives of the LIFE REDUNE project are the ecological restoration of the natural coastal zone, the reduction of negative human impacts on habitats and species and the integration of tourism with the conservation of the natural heritage, in an area - the northern Adriatic coast - where tourism represents one of the main economic activities and sources of income.

The dune systems involved in the LIFE REDUNE project are located in a tourist area, close to well-known seaside resorts that are very popular during the summer season.

For example, in the municipality of San Michele al Tagliamento in 2017 the tourist flow was 5,722,191 overnight stays. Despite the innate value of dune ecosystems for both human well-being and biodiversity, the relevant habitats have been subject to a long history of unsustainable exploitation and mismanagement.

While on the one hand tourism represents one of the most important elements of the regional economic system, on the other hand it represents the main threat to the conservation of dune systems. This is mainly due to a general lack of awareness of the environmental problems associated with coastal dunes, which include habitat loss, the spread of invasive alien species and habitat degradation due to tourism and recreational activities, as major threats. As a result, both the biodiversity of dunes and the related ecosystem services they provide are negatively affected, with the result that native species are threatened and habitat resilience is reduced.

Intense anthropogenic pressure, coupled with a lack of ecological awareness, is compromising not only the natural and ecological value, but above all the distinctive and identifying elements of the landscape that constitute one of the factors for tourist attraction..

Two and a half years ago, an initial series of monitoring and inspections was carried out to explore the existing ecological systems and draw up an initial list of habitats present in the four project sites, with particular reference to xerophilous habitats. Since then, the project partner European Project Consulting (EPC) has made several visits to all the sites, acquiring aerial images using a drone, a remotely piloted aircraft.

The processing of the data allowed the creation of a three-dimensional digital model of the terrain(DTM) with a resolution of 25 cm and updated photomaps of the working areas with a pixel resolution of 5 cm on the ground. From these printouts, a vector rendering of surveys, digital orthophotoplans and digital terrain models was produced. Subsequently, photo interpretation and video digitisation of the perimeters of the individual habitat polygons were created. This first draft of the map made it possible to identify the spatial discontinuities between the habitat types and to define the network of access routes to the sea resulting from uncontrolled trampling.

The attribution to the various habitat types was carried out by the University of Venice Cà Foscari through further on-site inspections and field surveys and the integration of information from vegetation surveys.

The analysis of the digital orthophotoplans led to the production of:

  1. a) an initial mapping of routes, walkways, tracks and areas with the highest tourist load;
  2. b) location of the discontinuity of the mobile dunes that should protect against marine ingress
  3. c) Habitat maps, with specific reference to the project and surrounding areas.

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All maps were produced at a scale of 1: 500. This information was included in a GIS (Geographic Information System) geodatabase, which is an integral part of the LIFE REDUNE project and is periodically updated. GIS is a computer system for acquiring, storing, controlling and displaying data related to positions on the Earth's surface. By linking seemingly unrelated data, GIS can help to better understand spatial patterns and relationships.

In the first phase of the LIFE REDUNE project, this high-resolution mapping enabled the identification of the complex micro-mosaic in which the same habitat is present in the same polygon at different conservation levels, proportional to the level of disturbance. This led to the definition of the fine location and quantitative composition of the native species to be included and the location of prohibited areas.

In the final phase of the LIFE REDUNE project, this system will make it possible to monitor and measure the effectiveness of the interventions carried out by the project.


A NURSERY FOR THE DUNE FLORA

The LIFE REDUNE project envisages the reconnection and restoration of 92,000 square metres of mobile dunes and the requalification and/or expansion of 823,000 square metres of transitional and fixed dune habitats, variously altered by disturbances caused by human action.

The restoration of the valuable coastal habitats can be achieved on the one hand by acting on the containment of the impact due to tourism and erosion and on the other hand by recreating the dune habitats through the implantation of native plants that accelerate the reconstruction of the vegetation cover.

LIFE REDUNE is "reconstituting" the dune habitats, with 151,000 native plants, germinated and grown in greenhouses, divided as follows:

  • habitats of the mobile dunes 2110 and 2120 (Ammophila arenaria, Elymus farctus, Echinophora spinosa,Medicago marina, Eryngium maritimum, Euphorbia paralias, Calystegia soldanella and others): 35,000
  • .

  • habitat 2130* (Teucrium polium, Fumana procumbens, Sanguisorba minor, Lomelosia argentea, Centaurea tommasinii, Globularia bisnagarica, Koeleria macrantha, Heliantemum nummularium ssp. obscurum and others): 45,000
  • .

  • habitat 2250* (Juniperus communis, Crataegus monogyna Berberis vulgaris, Viburnum lantana, Phillyrea angustifolia and others): 55,000
  • .

  • Habitat 2270* (Phllyrea angustifolia, Asparagus acutifolius, Rubia peregrina, Smilax aspera and others): 15,000
  • .

  • Stipa veneta*: 1,000
  • .

Native seedlings speed up the reconstruction of the plant cover where it has been damaged, at the same time subtracting land from harmful invasive alien species. According to studies conducted by the Cà Foscari University, for example, the invasive alien species Oenothera stuchii seems to be adversely affected by a high level of soil coverage by native species, while on the other hand it proliferates in areas most degraded by trampling and erosion which, by stripping the soil of its natural turf, makes it subject to invasion by this and other undesirable plants.

Stipa veneta is a priority species at high risk of extinction, of which fewer than 300 mature individuals remain in the wild.

Some of the most prickly plants in habitats 2250* and 2270* are used for the creation of living interdiction systems, in synergy with walkways, fences and information signs, to promote the use of only the permitted passages to reach the beach.

Ahead of the reconstruction work, therefore, there is a demanding nursery project conducted by Veneto Agricoltura's Plant Biodiversity Centre in Montecchio Precalcino (Vicenza). A regional structure specialising in the multiplication of native plants, the Centre actually transforms seeds collected in the wild into seedlings that can be used in the restoration work in the area.

A sequence of actions that begins with the search, in the wild, for populations of wild plants suitable for providing seed in sufficient quantity and quality to guarantee the "production" of the number of seedlings required by the project. This first, fundamental phase involves inspecting the area and requires botanical skills, a trained eye and experience. Once the most suitable wild stands have been identified, usually those with a high number of individuals, the seed is collected, taking great care to organise the collection days at the right time. If the seed is not yet ripe, in fact, harvesting has to be postponed and we have therefore made an "empty" trip: a waste of time and the unnecessary travelling of hundreds of kilometres. If, on the contrary, you arrive too late, the seed has already fallen and is no longer available. Nature seldom allows for a repeat performance, and arriving even a week late can sometimes force the production of seedlings to be postponed for a very long time.

For many of these species, it can take almost a year and a half from the day the seed is collected until the seedling obtained from it reaches the appropriate stage of development. This is why the best harvesting period, which is anything but constant over the years as it is subject to the direct influence of the climate and its unpredictable variability, is evaluated with great care by operators and often a few early harvests are preferred to a much more disastrous late harvest. It is interesting to note that, for most species in these environments, seed maturation is in summer. Harvesting therefore takes place on hot summer mornings: amidst the curious gazes of tourists in costume, strange men in yellow waistcoats move about, armed with bags, gloves and scissors.

Once the seeds have been collected, they are transferred to the nursery where they are treated differently according to the requirements of the different species. Seeds often show various forms of 'dormancy', i.e. they do not germinate as soon as they are sown. These are evolutionary adaptations of plants, which are not misled by conditions favourable to germination which, in nature, can be ephemeral: water and mild temperatures can be followed by drought, heat or frost.

Seed therefore germinates when the nursery can simulate the fulfilment of a series of requirements, varying between species. Sowing is done in alveolar containers: these are usually plastic or polystyrene containers with 32 or 45 holes, filled with a suitable substrate, corresponding to as many "pots" in which the individual plant will grow for the time necessary for its development. the assiduous effort, during all the months of cultivation in the nursery, is above all that of satisfying their water requirements so as to make them strong and resilient to the always possible biotic attacks. The batches of plants are therefore under constant monitoring, aimed at maintaining a delicate water balance and avoiding desiccation as well as over-hydration of the "loaves of earth" in which the young plants sink their roots.

The seeds, once collected, and the resulting seedlings will spend part of the summer, autumn, winter, spring and the whole of the following summer in the nursery: the latter season is decisive for the complete development of the stems and leaves. Their genetic patrimony, selected by evolution and adapted to respond to the inclemency of the pedoclimatic conditions thanks to the fact that the harvesting of the seed was carried out a short distance away, is the best guarantee of success for this difficult mission..


Never before have we "RE-DUNIATED"

On 12 November 2019, an exceptional meteorological event caused extensive damage to the entire Veneto coastline. Municipalities and trade associations are once again asking for interventions and structural defence works to mitigate the damage caused by storm surges. We are no longer thinking only of rigid structures in the sea, or of beach nourishment, which have already shown all their limits.

Now they are calling for the introduction of a new effective and eco-sustainable element of protection: dunes..

For years the European and global scientific community has been demonstrating the extraordinary importance of dunes as a natural mitigation element of coastal risk, be it erosion or, as in this case, flooding. Beaches and dunes are very dynamic environments with a high resilience. They are the result of slow processes of sand accumulation by wind and plants, the real engineers of the dunes. Plants slow down the wind and trap the sand with their stems and roots, triggering the physical process of dune formation. It is precisely this dynamic balance between sand, wind and plants that makes the dunes the "sacrificial elements" of the coastal systems: in the event of strong sea storms, they are partially eroded, but in this way they dampen the force of the sea, protecting the hinterland, and give the sand back to the beach.

The first two years of experimentation, in various points along the Veneto coastline, have allowed the Life Redune team, and all the stakeholders closely following the project, to verify and confirm the aspects that condition the correct functioning of the dunes.

The first aspect is time. The time needed for the plants to grow and effectively exercise their function as builders and consolidators of the dunes. If we analyse the historical data on storm surges, we can observe a certain time cyclicity of the most important events, but the cycles are getting shorter. We have little time, we have to start now!

The second is proper planning. Not only of how and where to build new dunes or reinforce existing ones, but also of their maintenance over time.

It is necessary to plan beach cleaning. Beached plants, algae and logs are not waste. Besides being an economic burden, the total mechanical removal of biological material takes a vital element away from the beach and the dunes. The removal of plants, algae and logs causes real physical and biological damage to the beach and dunes, removing a nutrient reserve for plants and exposing the coastline to a greater risk of erosion and desertification.

The third aspect, perhaps the most important, is the need to launch a pathway to integrate environmental sustainability and the value of natural ecosystems into local spatial planning and development processes.

The best time to intervene is from autumn to spring, and the REDUNE team has never stopped putting all its skills and strengths into both the design and execution of interventions, in order to have new dunes for next summer. At the same time, the team continues to train and share its knowledge with the local authorities in charge of coastal design and management.


Aliens in the dunes

Alien species are animal and plant species introduced by humans into areas outside their original range. In many cases, the new species are unable to adapt to the new environment and disappear after a short period. In other cases, they not only adapt but also spread very quickly to become invasive alien species.

 

The alien flora of coastal habitats

Despite their naturalistic value and ecological functionality, dune ecosystems share a long history of exploitation and mismanagement. The resulting environmental problems include habitat loss, impoverishment of the natural landscape pattern, a reduction in the resilience of plant communities and the spread of alien species, which have become increasing threats to native species.

Below we describe two of the most invasive alien species present among the flora of the coastal dunes of the Northern Adriatic.

 

Oenothera stuchii.

Oenothera stuchii is a hybrid originating in northern Italy from naturalised populations of Oenothera biennis L. and O. jamesii. The first report of O. stucchii along the Veneto coast dates back to 1952 and, after a period of pause, it now seems to be in the expansion phase.

The high success in spreading demonstrated by the species of the genus Oenothera is related to their ecology. Their two-year life cycle ensures their resilience and tolerance to disturbance: in the first season the seedlings sprout and the growth of the vegetative organs begins, while the generative phase is reached only the following year with the production of the epigeal portion. This two-phase germination can be blocked for years while waiting for favourable vegetative conditions. Seeds have a strong affinity for light and can go through a very long dormancy period in the sand, creating a "seed bank", while human activities (trampling, collection of materials, removal of sand...) bring them back to the surface, facilitating germination. The strong tendency to grow in the light, the rapid growth and the high number of seeds (5,000 - 12,000 seeds per plant) determine Oenothera stucchii's strong tendency towards invasiveness.

This plant also prefers habitats with wide open spaces, lots of light and a sandy substratum, conditions that make it more competitive in environments disturbed by human action, unlike endemic species that do not survive trampling.

 

The Life Redune project contains the propagation of Oenothera stucchii with an activity of emanual eradication within 150,000 square metres. Weeding takes place at the beginning of the growing season, around May, to prevent the production of new seeds and fruit..

 

 

Rosa rugosa

Rosa rugosa (or Rosa canina) is native to the Far East, where it is considered a wild plant. It has also spread to Europe and North America where it is especially cultivated for ornamental and decorative purposes. It is a perennial, very robust plant that tolerates frost and heat, drought and sandy soil.

Rosa rugosa is an upright, bushy species that can grow to one metre in height. The reason why it is called 'wrinkled' is because of its leaves, which have characteristic veins that turn very attractive colours in autumn. It blooms throughout the summer season, the flowers are quite large and can appear alone or in groups and have a very delicate scent.

The individuals that colonise beaches come from plants grown in gardens, but Rosa rugosa, due to its rusticity, is also often used in flowerbeds and along roads.

Rosa rugosa has a strong negative impact on native species richness due to its shading effect which reduces light on the ground. It also has a negative social and recreational impact on beaches as the invaded dunes become impenetrable due to the numerous thorns on the stems and branches.

 

The Life Redune project constantly monitors Rosa rugosa populations in the project's habitats to assess their rate of expansion and colonisation. In order to contain the spread of Rosa rugosa, Life Redune, together with voluntary environmental associations, organises bioblitzes to eradicate Rosa rugosa plants.

 

Invasive alien species represent one of the main environmental emergencies and are considered by the international scientific community as the second most important cause of biodiversity loss on a global scale. Their expansion threatens biodiversity, but often also has major socio-economic impacts, with direct damage to health or human activities.

Often the introduction of alien species is unintentional. However, many of the most widespread and dangerous invasive alien species have been imported into our country voluntarily. It is therefore important that everyone develops an awareness of the problem, thus transforming themselves from a potential vector of introduction to a sentinel against the further spread of invasive alien species.

 

For further information, see the website of the Istituto Superiore per la Protezione e la Ricerca Ambientale : https://www.specieinvasive.it/index.php/it/

In addition to the framework of the problems related to the introduction and spread of invasive alien species, the site contains the reference legislation, documents and technical guidelines useful for the correct application of the rule and the files of all the species included in the list of EU relevance for which a series of obligations and prohibitions are in force.