Ecology of the landscape
“Ecology of the landscape” is an expression which would go back to 1939. It echoed a unifying theory then emerging ( Landscape Ecology for English, Landschaftsökologie or Geoökologie (Géoecologie for German, landschapecology for Dutch…), near to the Biogeography, but more specifically being interested on scales known as “landscape” (or “éco-landscape” ).
It started to be conceptualized in the texts in the Années 1940 -1950 and continues to develop. Wiens (in 1997) distinguished three historical currents born from them in Europe and North America:
- a synthetic ecology and holist, where the man holds an important place,
- a traditional ecology, where the level of organization or the scale of study becomes broader (scale of the landscape),
- a rather space ecology, studying how the structure and the dynamics of the heterogeneous landscapes influence the ecological phenomena, and reciprocally (Turner, 1989).
The ecology of the landscape is interested in space-time dynamics of the biological, physical and social components of the humanized and/or natural landscapes. It associates for that of the disciplines such as the Géomorphologie and the study of the architecture of the landscape, ecology, the geography and social sciences. The centers of interests cover fields as varied as the study of the impacts of human development and ecological risks, the biodiversity and its evolution, without forgetting exploratory studies or the development of strategies of management, possibly restauratoire, and of fitting-out and territories, which can be socially acceptable. It is also a question of observing and of including/understanding the attitude of various actors with respect to the changes of the landscape. The ecology of the landscape seeks to identify the human factors, and ecological in return, which influence the organization of space, its heterogeneity on various scales, by combining the space approach of the geography and the functional approach of ecology
If the Écologie is interested in dynamics of the Biodiversité, in all the space and temporal scales, the Écologie of the landscape is interested particularly on an integrating scale of the landscape, the continents and planet, and in the evolution of the landscapes under the effect of the complex interactions between ecological processes and the organization of the space structures (that it is of natural or anthropic origin). Sometimes, the ecologist of the landscape acts on these structures (known as éco-landscape), either to study them, or within the framework of measurements of ecological rehabilitation.
To describe these structures ecology of the landscape had to develop new concepts, of which those presented below. It is possible that the air imagery which started to be diffused at that time, then the satellite imagery encouraged these new approaches, by allowing a better apprehension of the structures écopaysagères and by offering a new retreat compared to the landscapes and to their evolution. They are tardily only the mediums underwater or watery of fresh water were the subject of first approaches écopaysagères.
Principle-sourcesScientific observation of ground, as modeling let think that biogeographic heterogeneity (of spaces and the mediums) could have a function or an organizing virtue of the ecosystems, and conversely, that the ecosystems themselves strongly contributed to hétérogénéiser the mediums, in favor of a Biodiversité more developed. This heterogeneity is not - in nature - contradictory with the integrity écopaysagère or continuity écopaysagère which has a major functional importance for this discipline based on the fact that, to live, the individuals, and the communities of individuals of a species or several species require at one time or the other for their life and their evolution to move to reach their Ressource S, and that they are themselves often resources for other species or the ecosystem.
The ecology of the landscape recognizes that éco-landscape structures ( cf biological networks of corridors, of nodal zones, but also the “owner” and the “grain” of the landscape, its texture , its pedogeomorphologic roughness , and its characteristics… ) conditions the possibilities of access to the resources for these individuals and communities, in whole or part of a landscape, and in the case of the individuals at a stage or other of their life. The scales and degree of connectivity of the “spots” of the landscape also condition the access to the resources. This relates to as well fauna, the flora as the fonge or the microbes or that the communities which the species form within the ecosystems, agro-ecosystems, systems urban, etc
Complexity of the ecosystems seem to emerge from the tension fields and the structures visible or scientifically perceptible on a landscape scale. The ecology of the landscape tries to include/understand them and find the means of protecting them.
This discipline helps in particular with better including/understanding, attenuating and to compensate for the impacts of the fragmentation of the ecosystems by the infrastructures and human actions. It opens new prospects concerning the impacts of the climatic modifications and the ecoepidemiology.
- Matrix écopaysagère,
- ecological corridor (biological),
- Buffer zone,
- Spot, mosaic,
- Owner (pattern), grain, etc
Theory-mothersTo study and act on its subject (landscape like expression and condition of Alive evolving/moving in time and space), the ecology of the Landscape is based on the classical theories of Ecology.
It also developed a theoretical corpus adapted to its needs, of which:
Théorie of the hierarchy (which locates any phenomenon in its own spatiotemporelle scale, on the basis of the principle which there exists a correlation between scale of space and scale of times, and that they are speeds of operation of the phenomena which define the levels, the landscape being a level of organization of the ecological systems, which can be subdivided in lower levels (until the micro landscape, while passing by the ecosystem) and integrated in a succession of levels such as area, biome, continent, planet, each one of these levels being characterized by a clean heterogeneity, patterns (owners) and a dynamics that the Man generally does not perceive but which seems now especially directed by its activities.
- biogeographic Theory of the insularisation . It is one of the bases of the ecology of the landscape. In a very simplified way, it makes it possible to envisage the diversity of the species according to the distance which separates the island from a continent like certain qualities of the individuals (of which cuts and weight) according to the size of the island compared to the continent.
- Dependence of scale and space Resolution (grain)
- Theory of the Disturbance S allowing to model and quantify the disturbances at the origin of the heterogeneity of the mediums and/or of their fragmentation.
- Theory of the percolation (of gene flows, matter, individuals through a landscape) allowing to describe in geometrical terms the concepts of connection and threshold of percolation in space and time.
Of these theories results from this from others:
- * the éco-landscape fragmentation of the forms and structures (cf spots, volumes, edges, écotones.). One also speaks about parcelling out.
- * the connectivity écopaysagère,
- * the spatiotemporelle heterogeneity of morphologies, the facies and the association of species, the ecosystems, the ages, etc each one of these items being likely to influence the others)
- * the connectivity écopaysagère,
Applied researchSince the Years 1970 -1980 especially, the ecology of the landscape developed an important shutter “ Applied research ” through actions sometimes qualified of “ ecological Génie ” and via an offer of tools (model, indicating, cartographies) which aim for example to improve and evaluate the relevance and the effectiveness of the compensatory measures or academies. These last are developed (voluntarily, or more often pursuant to legal requirements) to reduce the environmental impacts of the great projects of infrastructures or planning and town and country planning, or at the time of ecological operation of rehabilitation of sites or degraded grounds.
Places and fields of applicationThe ecology of the landscape is a young discipline and in evolution. It is especially and initially applied to spaces terrestrial, natural, forest, agricultural and sometimes urban, but it starts to be interested in oceanic volumes where one discovers complexes networks of biological corridors and where concepts of zone-cores, buffer zones and corridors could contribute to a better management and protection of the fishing resources which are degraded quickly. After having ground these concepts and methods on the continuums which are the rivers, the network of the woodlands, the wooded bands or networks of trees… like on the physical and quite visible barriers such as the channels, roads and highways, railways, ends obvious factors of cut of the landscape, the ecologists started to study the barrier effect of a setting in agriculture or sylviculture of a natural environment, then they refine their knowledge on effect-barrier more subtle such as, for example, those create by;
- the disturbance;
- changes of odor of the environment (For certain species with the very developed, landscape, night olfactive direction in particular seems to be initially a landscape of odor);
- rupture of a thermo-hygrometrical continuum;
- the presence of Pesticide S in the air and the rains, fogs or dew, etc
Another new field of investigation is that which one can by convenience call the night Environnement for which the luminous Pollution, phenomenon into full expansion (+ 5% per annum approximately), seems to be a powerful factor of ecological fragmentation.
Elements of ecology of the landscape start to be taught in the schools of landscape and certain agronomic or forestry formations.
The Man and the ecology of the landscapeBy associating a biogeographic and sometimes social approach and history with traditional ecology, the concepts of the ecology of the landscape make it possible to better study the impacts of the human activities, which seem become the major factor of evolution of the landscapes, at the planetary level.
HistoryAfter one long period devoted by the naturalists to inventory and classify the species, appeared a functional approach which was specified in ecology, for example with the importance of the relations predatory preys, within ecological niches; an ecology of the systems and ecosystems, very mathematics and modélisatrice integrating stocks, transfers and flow of energy on biogeographic scales, with a certain difficulty of integrating the increasing impacts of the human activities, as if there were ecology, theory of nature without the man and the geography and the social sciences which would be other thing.
CriticismsHis beginnings one reproached ecology landscape:
- its complexity, a mathematisation or excessive modeling,
- lack of argumentation of its theories and in particular lack of reasonable evidence of the reality of the concept of corridor biological or percolation écopaysagère.
- production of a new definition of the Paysage other than that of the geographers or landscape designers, (déf. of Augustin Berque or Alain Roger)… as if there were two different landscapes, that of the ecologist where the beautiful one would not have anything to make and that of the esthète where the value écopaysagère would not have a direction.
- It not taken into account of ladders and standards of the Geography (of INSEE in France) or of the Atlas of landscapes when they existed…
- an insufficient taking into account of the history of the landscapes (it is the case of certain studies), but by principle the temporal approach implies the taking into account of nonlinear complexity of the transmissions, and until the sociocultural appropriations of spaces
- an excessive focusing on the isolates and insufficient on the matrix…
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