Green Screen

The green screen is a concept which in the French-speaking countries dates from the years 1980-1990. For the years 1990 to 2005 this expression covers various realities, according to the time, the country, or the field considered (Urbanisme, Paysage, Environnement, projects of local government agencies…).

One can classify the green screens in 2 categories:

  1. . .un network more or less physically connected green areas, without strong ecological requirement or coherence, often structured around ways of walks or excursions.
  2. . .un ecological, local or regional grid, whose design and follow-up are based on an approach scientific and generally accompanied by a cartography SIG as well as indicators of results. This last category is often the fact of cities, or great agglomerations of Northern Europe.

Definition in the form of metaphor

To facilitate the exchanges between actors concerned, the District council of the Nord-Pas-de-Calais and the DIREN of this area have in March 2000 enriched their definition by green screen by both Métaphore S: We understand intuitively that the green screen is a biogeographic concept which, by analogy with the screen of a fabric, evokes at the same time a state and fonctions.
As image, the wire of mesh and weft threads confer its quality on a fabric: more the wire are weakened, or missing, more the fabric threatens of déchirer.
In a metaphorical way, in the image opposite, one can imagine that each bit represents a species, that each wire is a group of species or an ecosystem, and to consider that beyond certain threshold of degradation, it is all the fabric (the biodiversity, or biosphere with more large scales) which is menacée.
Metaphor such a simple, but in conformity with the complexity of reality, would be to compare the green screen with the grid of the blood, nervous, lymphatic networks which must be not only in good state, but correctly connected between them, like with our cells and our bodies, to ensure our survival .

Tally: the Sustainable development

In the theoretical and practical fields of the Biogeography, Ecology of the landscape, and pursuant to the principles of the bearable development such as defines in Rio with the Sommet of the Earth, the concept of green screen returns to the more precise concepts of ecological Maillage, of natural Infrastructure (or Réseau X of biological Corridors).

When certain actors of the Town and country planning started to integrate these concepts, the expression weaves green then could indicate the regional or local variation ecological Réseau paneuropéen or network EECONET (for European ECOlogical NETwork) proposed by the the Council of Europe.

A concept which evolved/moved with time

For example in the North of France, whereas the District council since 1993 within the framework of a project known as Projet Ecotone launched, with DIREN a dynamics of study and restoration of an ecological grid (regional screen ecological), being pressed on an experimental tool said Contrat of corridor , the General advice of North, with CAUE of North published a sorter entitled green Trame , which placed at the disposal of the elected officials and inhabitants of the Department the first classification of the landscape entities, but without the concept of biological Connectivité or écopaysagère. Whereas the urban community of Dunkirk produced a “green land register”, an work group associated in Eurorégion Kent, Wallonia, Brussels capital and the Nord-Pas-de-Calais in a common reflection on the biodiversity. Brussels-capital set up a Regional plan of development aiming at “improving the framework of life” (chapter 9 - page 15), which recommends a “grid green and blue”, which, being given the urban context does not give priority to the Biodiversity, also consisting in “connecting the green areas between them in order to create green continuities and to offer thus to the citizen, where who it is downtown, of spaces of life and displacement which combine at the same time user-friendliness and safety”.

In France, pursuant to the Law Voynet, the country started to decline in its National right the Stratégie paneuropéenne for the protection of biological diversity and landscape. DIREN S of the French areas then drew up each one a regional environmental Profil, within the framework of the Schéma of collective services Natural spaces and Ruraux. The district council Nord/Pas-de-Calais then installed with ADEME a tool allowing the agglomerations also to draw up a local environmental Profil.

Then, a green and blue Trame (or TVB) was prepared, defined then installation by the district council with many actors (scientific, associations, communities…). In this same area Nord/Pas-de-Calais, the concept of grid ecological also has and for the first time included in a regional Atlas of the landscape. Thus during time, one passed from a project directed towards the landscape to a project aiming at the restoration, protection and management of the mediums and an ecological defragmentation of the territory.

Contributions of the ecology of the landscape

After the innovating concept of natural Infrastructure used officially for the first time in France in 1994 by the prefect Paul Bernard for his report/ratio on the Wetlands (September 1994), and with the concept of network of biological Corridors, cores and zone-plug, the concept of green screen was preceded then introduced into the field of Town and country planning via them and the regional environmental Profil that the DIREN have to produce. In parallel, a certain number of universities or universities developed certain aspects of the Écologie of the landscape (with Rennes, Montpellier, Besancon, Nantes in France, for example).

But the ecologists lately trained with these concepts did not arrive immediately in the administrations and local government agencies. It is only in years 2000 that the communes and Agglomération S truly seized these questions to concretely decline them in their management of the territories. Thus in France, the urban community of Dunkirk had it as of end of the year 1990 set up a registers green , thus - with CNFPT - that a formation on differentiated management. In the same area, the Mission field produced a " Green screen of the Basin minier" , the urban community of Lille bought spaces in particular to rehabilitate them with the Parc of Deûle, aiming at an ecological reconnexion with the peripheral Belgium and green screens (of which that of the field), whereas many other cities integrated little by little whole or part of the concept of screen ecological, sometimes by associating with it the inhabitants within the framework of a Agenda 21 or Community gardens for example.

Scientific aspects

In term of ecology of the landscape a green screen is the sum of the zones of biological connection and of the connected natural habitat S.
, in other words: the network of the elements of territory and mediums which constitute or connect between them:
them natural habitats of the flora and fauna savages and spontaneous,
them sites of reproduction,
them sites of nourrissage,
them sites of rest and shelter,
them “corridors” (corridors) of displacement (of which migrations) of the wildlife,
them “corridors” (corridors) of dispersion of the flora.

The state and the quality of the Screen are measured in the quality and the quantity of the natural habitats and biological connections between these habitats. The habitats are to some extent the nodes of the grid, and they play the part of reserve of genes, species, communities for the biodiversity.

The components of the green screen are often in fact of the biological or physical continuums.

  • They can be continuous or in " pointillé" (one speaks then sometimes about structures in ford).
  • They can be permanent or not (cf migration of the birds, fish, Amphibians, insects), different according to the species or groups from species.
  • They can be " immatériels" (migratory axes of the birds, marine fish).

As example, are regarded as elements of green screen: certain forests, the wetlands, the slopes limestones, dune zones, cliffs, hedges, insofar as they constitute mediums more saved by the impacts of the human activities or infrastructures (Perturbation S, Pollution S, Bruit, luminous Pollution, Engrais and Pesticide S or direct destruction).

Perfectly functional biological corridors for a great number of species can also result from human installations which did not have vocation to create them. Examples:

- Networks of the woodlands, slopes limestones and ripisylves, moors, forsaken.
- road Slopes, edges of channels, Drainage works S, networks of ditches, railways,
gardens,
- Careers
- industrial Waste lands…

Multi-scale

the green screen appreciates on all the space scales ; for example:
- on a corridor scale large of migration for the birds,
- on landscape scale (for the terrestrial mammals),
- or on more local scale (bank of river, ditch).
- on various scales administrative (country, area, (town and country planning) Country (within the meaning of the Law Voynet), Department, Regional natural park, Agglomeration, city, etc;

It is also appreciated in time :
certains corridors fulfills their function only at certain times of the year (ex: corridors of migration for the Amphibian migrating S, fish, birds or butterflies), or punctually during migrations imposed by climatic risks or of fires type…

Thus, as example the green screen of agglomeration of the SCOT of Dunkirk holds it account at the same time of the regional green screen and the projects and potentials of the communes.

What is not the green screen

- All habitats abnormally ecologically fragmented,
- All mediums which would make difficult even impossible the normal circulation of fauna and the flora savages (by ex: cultivated fields in an intensive way (cf Pesticide S Biocide S), urbanization, and all infrastructures splitting up the continuums écopaysagers (ex: an axis TGV weeded, drained and provided with its double fence insuperable for the majority of the species, except at rare the point is provided with a passage to fauna or écoduc) whereas an infrastructure in tunnel maintains continuity landscape and possibly écopaysagère).

Contrary to certain generally accepted ideas:

- the green screen is not landscape installation with the current direction of the term, even if it “produces” Paysage and Aménité S.
- the required objective is not firstly esthetic, nor economic, but quite patrimonial, even if it brings also very many benefit (cf the ecological services " gratuitement" returned by the biodiversity).
- the green screen is not systematically végétalisée: sea, water surface or certain underground rivers, sand, cliffs, rollers, caves and underground mediums, are elements.
- Its structure is not fixed: it is about an alive mosaic which must be able to evolve/move, assembling the varied stages of development of habitats having dynamic evolutionary clean and interdependent ones; these dynamic being affected more and more by the influence of the Man in time and space.
La total function of ecological connection which founds this screen, must, it, on the other hand to be durable…

Objectives

A green screen generally has a objective triple : to restore, protect and manage in situ the biodiversity, by supporting some car-maintenance, by the maintenance of the minimal conditions of life and circulation necessary to the survival of the species. This step is with opposite this that of the Zoo, but can integrate a network of natural reserves like zone-refuge or cores of biodiversity and swarming.

The creation of a green Screen theoretically aims a “appreciation” for the ecosystem and the Biodiversity, overall, and thus in favor of the vegetable kingdoms, animal and fungic, and of the micro-organisms. It should never be carried out with the detriment and/or in substitution of a natural heritage of value. Nevertheless, at local scales, it arrives, temporarily, that for scientifically justified reasons part of the green screen (certain types of biological corridors, buffer zones or cores.) are conceived to support one or more species threatened, or considered to be priority (ex: species pionnières or secondaries to heal a degraded landscape, or remarkable and vulnerable species or whose conservation is considered to be priority in the context of the moment).

For example, the plantation of a Peupleraie in a Wetland, even if it can provide the function of ecological corridors for some species, is to be proscribed, because it replaces an element of green screen existing (the wetland), rarer, richer than the aforementioned poplar plantation would make disappear.

The concept of patrimonial hierarchisation , permitted by an initial state of quality is thus the essential precondition to any decision of installation of green screen.

Functions generally allotted to the green screens

One allots to them two ecological functions principal :

  • Restoration and maintenance of the “habitat S” rich person in biodiversity, “ habitat ” given that here within the meaning of natural habitat, and in Europe, has minimum within the meaning of the Directive " Habitat" European.
  • biological Connectivity; it is a question of offering optimum conditions “normal” or for displacement for the species (and thus the Biocénose S, the Gène S…) who should normally circulate on a territory given in the absence of marked human print.

Legal aspects

Certain countries (ex Germany; regional or urban laws) protect in the law a network indexed from ecological infrastructures

In France, the screen, as a coherent natural network, as under consideration by the Diagram of Collective “Natural spaces and rural Services (SC ENR)”, is a requirement with the durable maintenance of the dynamism of the biodiversity. The EU and her Member States were committed stabilizing the regression of the biodiversity before 2010. France committed itself declining on its territory the Stratégie paneuropéenne for the protection of biological diversity and landscape.

The DTA (Directive territorial of installation) or the local documents of town plannings, the regional charters of natural reserve, the payments of natural parks, the SRADT (regional diagram of town and country planning), agrienvironnementales measurements, etc can contribute to the protection of the green screens and the ecological networks.

In theory, the new CAP should in the European Union encourage a durable Agriculture, and thus in the agricultural landscape the protection of a ecological network useful by many aspects for agriculture itself. (Protection of the grounds, the animals, the auxiliaries of agriculture, fights against the Sécheresse, the Inondation S and the erosion and the impoverishment of the soil, protection of water against the Nitrate S, Phosphate S and Pesticide S, etc). In France and in some countries, in certain contexts of the enherbées Bandes is obligatory.

Remarks

The developers forget often certain important dimensions, of which:
  • need for integrating, as far as possible, whole or part of the year:
    • of the corridors of “ calm silence ” or “ ” to answer respectively the problems of fragmentation by the noise and the disturbance possibly related to the surfrequentation.
    • of the corridors of “black”, where the effects splitting up of the luminous Pollution absent or are at least mitigated.
  • a necessary partnership, with many actors, of which for example in France:
DIREN, DDE, DDAF, CETE, area S, department S, Agglomeration S and all communities, structures inter-commune, owners, private individuals, consular Rooms, developers, farmers, users of the territories, Academies, ONF, SANEF, the SNCF, VNF, SRPV, ONCFS, SAFER, etc

The landscape designers start to seize these concepts; the topic of IIes sitted European of the landscape (May-June 2006 in Lille, France) was: landscape, a project for the planet .

Example

Many countries of Northern Europe have a work in progress on an ecological network.
  • Belgium: all the areas applied the concept, including in urban area with the policy of the “green grid” and the “blue grid” of the Area Brussels-capital.
  • France: Was tested since 1996 in the Northern area - Pas-de-Calais some “ Biological Contrats of Corridors ”, which prepared and preceded a more ambitious regional policy by green and blue Screen, scientifically supported, with for object Co-building an ecological network with the local actors, and the Belgian and English neighbors, for a coherent and relevant ecological mending of meshes of the territory. Within the framework of the Diagram of collective service “Natural spaces and rural”, it was the occasion to try out and implement on the scale of the area the concept of network ecological and biological corridors. With more large scales, it is the local application of the ecological network paneuropéen which is concerned. At the end of March 2007, a plenary session of the district council validated this project, after a working session shared with the CESR. The synthetic cartography and the method are placed at the disposal of the public on Internet site of the regional SIG.
The area Alsace and the Département of Isere are also pioneers. The regional natural parks work there much since the years 2000, with a number 53 of the review of the parks devoted to the biological corridors in 2005.

See too

Related articles

External bonds

  • downloadable multi-media Assembly/Northern Area/Pas-de-Calais
  • Access to the charts (interactive) and explanations of the '' green and blue Trame '' of the Nord/Pas-de-Calais Area area
  • Call to project/European transnational co-operation

References

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