Natural Habitat

The habitat is a concept used in the field of ecology to describe the place - or more precisely the characteristics of the - in which a population of individuals of a species (or group of species symbionts or living guild ...) can live and grow normally;

Posidonia meadow ( Posidonia oceanica ) in the Mediterranean. This herbarium is a habitat for many animal species and some are subservient. It is itself part of a larger habitat. Different habitats and can be "nested" into each other, forming ecosystems, and it evolves dynamically

Some species have specific ecological preferences and limited, unlike the ubiquitous species at large " ecological envelope. They are the most susceptible to degradation, fragmentation and destruction of their habitat (here, a sea slug curled (Elysia crispata) a species of tectibranche locally common, but in the Caribbean )

It would normally talk about the habitat of a population rather than a species or an "agency" as it is for example possible to accurately describe the habitat of a single bear in the Pyrenees, the species should consist of a into many groups of people (subpopulations) living in habitats more varied than those in which the last individuals of this species trying to survive, the species was once common in throughout Europe, the coastal lowland mountains. In terms of habitats , the Pyrenees are in no way representative of their optimal habitat. They are their last refuge, the one where they were hounded and hunted the least.

The habitat is an element or combination of elements of the landscape that provides sufficient resources to enable a population of a species live and reproduce normally on that territory; Some authors suggest that habitat (for it evolves) does not imply a long-term viability for the species living there, but at least short-term viability ^{, ,} .
Destruction, alteration and fragmentation of habitats by humans are major causes of species loss and decline in biodiversity. Meffe & Carroll (1997) estimate that these are the main threats to biodiversity;

Reality more complex and nuanced

This ruin has offered an alternative habitat for bats ( protected species ) and other cavity nesting organismmes. It was protected (with grid) for this reason ( Frankfurt / Oder , Germany)

Besides semi-natural habitats, we construct some alternative habitats totally artificial, as this cottage for bats at the University of Florida (USA)

In reality the boundaries of a habitat may be a bit fuzzy, with soft passages one habitat to another habitat, or more often a patchwork of all positive (or neutral) with respect to the species.

Within a habitat ( forest , for example), there are various sub-assembly (or "micro-habitats), which change over time and which are each more or less" optimal "for the tree species considered.

Habitat or microhabitat is "optimal" if this element in the mosaic copaysagre, reproductive success (fitness) of the species and optimal . We will discuss sub-optimal habitat, if it is a middle alternative (natural or artificial) where the species survives, but with difficulty and with abnormally low reproductive success. Anthropogenic landscape changes have imposed many species live in habitats known as "suboptimal" in which they can survive for some time, and with a reproduction rate or a reduced lifetime.

It was thus shown in the years 1980 an Australian threatened species , the Lord Howe Rail ( Tricholimnas sylvestris ) following the introduction of the boar by the man on the island where the bird lived, was the refuge for survival in a suboptimal habitat (at the top of the island). The species had survived, but regressing and relict populations, with a reproduction rate decreased.
Eradication of wild boar on the island has actually been quickly followed by the return of the bird in its habitat optimum, with a restored reproductive success.
In this case, the habitat was physically present and seemingly always optimal, but it had been rendered inaccessible to the species by the introduction of another species, the wild boar.

How to define a habitat?

A habitat is usually defined in relation to a species (eg habitat Black Woodpecker , which implies the presence of dead trees or colonized with boring ) or relative to a coherent and balanced community of species ( guild , ecosystems ), primarily because the dominant species often shape their habitat, as they are forced by him, then because many of them contribute to the construction or modify it for them (eg Sphagnum more resistant than most other plants to acidic, acidify strongly settings where they live, allowing the persistence of peat bogs for thousands of years).
The habitat may well be defined in relation to species that are specific.
Unless otherwise stated, it generally includes the habitats of substitution as well as breeding or artificial substrates in the habitat of a species.
For some species calm conditions ( silence , absence of fault ) or quality of the night ( nocturnal environment protected from light pollution , in addition to that of the physical and ecological).

For species that are very ubiquitous , migratory or operator of large areas or volumes of the environment, limitations and characteristics of a habitat are sometimes blurred (or stop habitat gray whale ? habitat of the house martin it includes its migration corridors and feeding areas all?)

For these reasons, it is often the plant habitat characteristics that are selected to define and describe it (more often using the phytosociological and Europe codes " Corine Biotope ", based on the fact that plants somehow reflect the nature and evolution of the medium, substrate and ecosystems. In these classifications, habitat (eg Lande) is subdivided into habitat types ('acidic heath Heather "," moor paratourbeuse "," wet heath "or" dry "...)

A habitat can be a body , a super-organism (eg, coral ) or organ (eg, our gut has a set of symbiotic microorganisms or not weighing up to several kilograms, said " microbiota ". Many species highly specialized ( exoparasite , endoparasite , some symbionts are housing an organ or body of another species)

Issues of nature conservation

Habitat conservation is the central issue of the Nature Conservancy and must remain in sufficient number and size, and with ecological connectivity sufficient and relevant in the case of mosaic or habitat networks. Their ecological integrity is also important, as they are increasingly fragmented , which is why in the world and construction of various strategies remeshing ecological habitats by biological corridors are tested and / or implemented until scales below those habitats.

Ecology and habitat protection

In the twentieth ^century, conservation has evolved from the concept of protection of species than protecting populations and ecological networks of habitat, including the conservation biology based on conservation Joint habitats and species that live and build and maintain ..

The World Wildlife Fund has sought to represent the Earth's surface ecoregions , areas, terrestrial, marine or freshwater. To make this determination, WWF has divided these three areas (terrestrial, marine and freshwater) in "major habitat type, which can describe the different geographical areas sharing similar environmental conditions, habitat structures and comparable a beta diversity. These habitats are generally comparable to the major biomes. WWF has identified 14 major habitat types in terrestrial, freshwater and 7 in 9 in sea area.

In Europe

Europe and its member states have to share their habitats defined as "terrestrial or aquatic areas distinguished by their geographic, abiotic and biotic features, whether entirely natural or semi-natural." A directive specifies that certain habitats are of Community interest. These are the habitats that the territory covered by the Directive;

• are endangered (in their natural range) or
• have a small natural range, following their regression or by reason of their intrinsically restricted area or
• are outstanding examples of typical characteristics of one or more of the seven biogeographical regions of the Euro (Alpine, Atlantic, Boreal, Continental, Macaronesian, Mediterranean and Pannonian).

In the twentieth ^century the trend has been a sharp deterioration in the quality and surface habitats. In 2010, significant gaps still exist in the quantitative and qualitative knowledge of marine habitats; In the balance sheet (2010) Assessment of natural habitats of Europe, the percentage of states "unknown" is much higher for habitats and species in marine regions (57% of species whose status is classified as unknown in 2010) than for those terrestrial areas (27%). Moreover, the quality of available data is considered bad for the marine populations (nearly 60% of cases in 2010) twice as often as for terrestrial species (35% of cases) .

The Habitats Directive Fauna Flora "

This Directive European, 21 May 1992 on the premise that it is illusory to seek to protect species and their ecological functions if you do not protect and also their first home.
It aims to promote good conservation status of priority habitats for the maintenance of biodiversity in Europe, taking account of economic, social, cultural and regional recognition in the European context of the twentieth ^century, maintaining biodiversity may "in certain cases require the maintenance or even encouragement, of human activities." It relies on the protection of natural habitats of wild fauna and flora in 6 major bio-geographical zones of the territory of the European Community: Atlantic, Boreal, Macaronesian, Continental, Alpine and Mediterranean. It complements the Birds Directive and Special Protection Areas ( SPAs ), incorporating the commitments of the Berne Convention (1979). This is one element of the constitution of the European Ecological Network , which relies on special areas of conservation ( SACs ), called " Natura 2000 "(Article 3) forming an ecological network coherent European.

Classification as an SAC does not necessarily stop or even changes in economic activity but requires the establishment of a document of the target of sustainability or restoration of biological processes and elements necessary for the conservation habitat types or species called "European interest" for which they were designated. Member States propose to the zonation of Europe and implement the documents of objectives. National and European funding can help farmers, foresters, etc.. implement management actions restauratoire or conservatory. This directive is a goal that is a condition of sustainable development , sustainable conservation of a minimum amount of functional habitats.

Management has provided a timetable, and asked for programs to improve scientific and technical knowledge, as well as education and general information regarding the objectives of the Directive, some countries, including France, have applied with considerable delay and with gaps. For reasons of subsidiarity , the directive was exclusive in the Natura 2000 network sites of European interest. It is up to member state to decline further action at their level. Local authorities are contributing more or less according to the laws of the country. Member States shall take appropriate measures to avoid, in special areas of conservation (SACs) disturbance of the species for which the areas have been designated, since these disturbances can have a significant effect to the objectives of the Directive. The "deliberate disruption" of a species protected by the Directive, particularly during the period of breeding, rearing, hibernation and migration is prohibited. The definition of the concept of disruption and inconvenience has led to lengthy and difficult discussions, particularly in France concerning the disturbance by activities of nature, fishing or hunting. It is still subject to interpretation.

mapping of natural habitats

At the end of the twentieth ^century, the need emerged to map more precisely the habitat, and ecological networks for the needs of managers of natural sites and for homogenize the map data acquired by local actors, to 'allow aggregation at the national level and pan.
In Europe for various purposes including for the Birds "and" Natura 2000 ", and to map the Special Areas of Conservation (SACs) for habitats books (see Habitats Directive , EUNIS , etc.. of means of maps and codes were invented and shared by member states, later for underwater habitats. These cards (systems CORINE CORINE Biotopes ..) are essentially based on benchmarks, criteria and classifications phytosociological .
In France, at the request of the Ministry in charge of Ecology, a guide for a standardization of maps was published in 2005 by the National Museum of Natural History and the Federation of National Botanical Conservatories. Corine Biotopes a repository has been updated to France in 2003

This mapping happens today by 4 steps

1. Characterization of habitats and species identification (using available data, including field surveys, necessary to validate data from any already aerial and satellite images, atlases, etc.).. At this point a classification of habitat is established and validated. Choice of mapping scales (which should be fairly thin because of ground level condition of those refunds regional and national, knowing that over a scale is finer, the mapping will be asked to work and time). The finest scale is often 1 / 2, ⁰⁰⁰ (for example, used for management of natural environments), the 1 / 25 000 is often used for regional or national syntheses.
2. Surveys and Mapping, according to the typology. The data, georeferenced, are plotted on base maps from d ' orthophotos Digital (sold by the IGN in France), or additionally from beyond BD Topographic or "Scan25 IGN. The minimum scale used in France to map habitats and sites of plant species is the 1 / 10 000 ^th (map, 1 cm represents 100 m on the ground) .
3. Creating a geographic information system, enabling to organize, view, and use these data (provided by E00, MIF / MID or. Shp. And made in. Xls,. Mdb, or. Txt with tabs).
4. Restitution in the form of maps, writing descriptive notes habitats ... This requires going through a geographical projection system. To prevent excessive deformations, France was divided into 4 zones (north to south) with corresponding projections Lambert I, II, III and IV. The national overview maps are made by a special screening (known as "Lambert II extended"). Lambert II carto system enables extended stack the various layers of GIS information in a local or national same projection system ..

Scientific validation of data is done at each stage, by the National Botanical conservatories (known as validating the national green and blue (TVB) by Bill Grenelle II , and final nationally by the National Museum of Natural History. Regular updates are planned for the monitoring of habitat changes.

There is also an observatory in France and IFREMER coastal and other more specialized in the marine realm.

Repositories

They are many. For example for France:

• Prodrome of vegetation of France,
• bryosociologique synopsis for France
• Corine Biotope ,
• habitat classification of Palearctic ,
• EUNIS Habitats
• Natura 2000 ,
• Cahiers d'habitats

France

The Grenelle of the environment , the law Grenelle I and II Grenelle law and the work of preparation or implementation of the green and blue , have accelerated work on habitats. There is now talk of habitats that are critical habitats of species known as (the list varies by region). These habitats must be sufficiently functionally linked together to allow the ecological connectivity in the species.

References

See also

Related articles

• Biota , biota , ecological niche
• Ecological integrity
• Environmental engineering , conservation biology , management differentiated
• Habitats Directive
• Naturalness
• Nature Protection
• Reintroduction
• EA

External Links

• Illustrated examples of habitats and features of great interest for biodiversity in France
• Repositories Habitats (the site of the National Inventory of natural heritage , for France)
• Conservation status of species and natural habitats of the European Union , Luxembourg: Office for Official Publications of the European Union, 2010.

Bibliography

Regarding the inclusion of habitats in the green and blue:

• TVB Guide COMOP 1 (Operating Committee green and blue), Writing and coordinated by Cemagref MEEDDM, 2010, "Strategic choices likely to contribute to the preservation and the restoration of good ecological continuity. First document to support the implementation of the green and blue in France, 73p.
• TVB Guide COMOP 2, Drafting coordinated by Cemagref and MEEDDM, 2010; "Methodological guide identifying issues and national borders for the preservation and restoration of good ecological continuity and having a component for the development of regional plans of ecological coherence. 2nd document to support the implementation of the green and blue in France, 127 p.
• TVB Guide COMOP 3, Drafting coordinated by Cemagref and MEEDDM, 2010; "Taking into account national guidelines for the preservation and restoration of good ecological continuity by major line infrastructure of the state and its public institutions. The third document in support of the implementation of the green and blue in France, 120p.
• TVB submitted by officials at the TVB conference COMOP green and blue, organized by NEF in Lille in 2009 (11 pages, pdf, accessed 2010 03 08)
• Marie Bonnin. (2006), corridors, sustainable management of vector space in favor of protecting species, Natures Sciences Socits, 14: S67-S69.
• Marie Bonnin, Ecological Corridors, Toward Third Law of the Conservation Collection Law Cultural and Natural Heritage, L'Harmattan, 270 pages, 2008.
• ALSACE NATURE - October 2008 - "Infrastructure and ecological continuity. Methodological study and application testing in Alsace, "Study Report to the Minister of State Jean-Louis Borloo, 134 p.

• Ecology portal

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