A écotone is a ecological zone of transition between two ecosystem S. For example, the passage of savanna to the forest, or the passage of an alluvial plain at a noneasily flooded zone. As in the case of the biomes, the vegetation plays a big role in the characterization of a écotone, because of dominating physiognomical mark which it prints with the landscape.
History of the concept
It is a recent concept, going against the over-simplification inevitable of classifications, and carrying many reflections on relativity space and time, and on the great variability of the phenomena observed according to the scale of the observation (local or regional).
Spatiotemporelles scales
The scale to which a écotone can be considered, varies according to the biomes, of the ecosystems observed, but also of sound not of time. The littoral écotone is for example mobile in time (cf erosion of the feature of coast, silting or aggradation thanks to the Mangrove). it can have a certain dimension Fractale, and a écotone can contain others of them. One can say that the concept basically underlies the idea that the natural environments cannot, in the majority of the situations, being delimited in a clear way, but which there exist always zones of transition where one finds in mixture of the characteristics of the two separate and linked mediums at the same time, by the écotone.A écotone can be moving in space and time, horizontally and vertically, for example with the liking of the tides on the intertidal zone, and with the liking of the seasons (of the rains, or winter) for the shores of Fleuve S and lakes and the coast S navy. In nature, when water is withdrawn slowly winter at the summer (of the rain season at the drier season), the plants can germinate, grow, flower and bear fruit during one longer period in the year, offering a more durable food resource to the animals, and increasing their chances to remain. In a basin (of public garden or private for example) artificially maintained on constant level, this characteristic disappears. So moreover its bank is high and tight, this écotone becomes an edge which makes obstacle with the circulation of water and the biological movements between outside and the basin him even. (In ecology of the landscape, such a basin can be regarded as a “spot” , more or less isolated in a “matrix” (its environment); its form and its size will influence over the linear length of bank, the articifialisation of this bank will influence its écopaysagères qualities and its functions “écotoniales” .
The forest edges all and the natural écotones evolve/move in time, on periods or cycles (tides) more or less long, secular at millenia in the case of the natural forest.
Edge and écotone
The concept of edge is rather used for a geographical or landscape description of the mediums, whereas that of écotone is to describe the ecological operation of complex edges (and normally often moving) in space and time. In ecology of the landscape, one says that the edge is a écotone. A biological Corridor linear making the interface between two mediums can be qualified of “ écotonial ”. As regards Cartography of the biological corridors, for example in a project of green Screen, a zone of écotone can also be regarded as “zone-plug” , to protect the “heart from habitat” (Zone-Core) and to make a soft transition with the “matrix écopaysagère” .See also: Edge
Related articles
References and Bibliography
- Dangerfield, J.M., A.J. Pik, D.Britton, A. Holmes, Mr. Gillings, I. Oliver, D. Briscoe, and A.J. Beattie. 2003. Patterns off invertebrate biodiversity across has natural edge. Southern Ecology , 28:227 - 236.
- Gilles Clement, Proclamation of the third landscape . Little book in particular treating écotones as ecological systems and also landscapes.
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