Please give me a simplified answer.
I know that the ecotone is the transition zone between 2 ecosystems characterized by its species richness (Exp. Between an agricultural land and a forest). Is this the same thing for a sampling quadrat, where we must avoid the boundaries? I have read that the edge effect for a circular quadrat is less important than for a square quadrat? I did not understand very well.
Thanks.
There in no any term 'border effect' in ecology. 'Edge effect' is term which refer to changes in population or community structures that occurs at the boundaries of two communities.
Thank you Mr. Singh,
In French , we use "Effet-lisière" or "Effet- bordure" = Edge effect.
In experimental design it has been shown that the border areas respond different than the center portion of the same plot. Experimenters will use a 6 row plant harvesting plot by using the 4 center rows for harvest to eliminate this effect of border rows. Since transition areas can be more productive farming systems featuring small fields can take advantage of the edges to increase overall productivity. A windbreak with reduce the flow of wind some ten height distances from the wind break. This effect can improve productivity when wind damage is mitigated and loss of water from evapotransition is reduced. When plants are favored by shade a big edge effect can also be used to advantage. In terms of biological control which is a function of beneficial habitat is often associated with the diversity of habitat and food resource the edges provide. Because small fields take more farmer effort modern industrial farming has worked to eliminate this important edge effects much to detriment of the overall environment.
Dear sir,
Thank you for your answer.
What I would like to understand is that sometimes the boundary between a forest and another ecosystem (For example an orchard ou a lake) is just a line. How to delimit this line and see the edge effect?
In the literature, it is said that it is the ecotone, which is rich in species. Is it possible that this line separating the two ecosystems is richer than the forest and the orchard?
Thanks.
Hello,
You may find some useful details in this poster where I explained that there are indeed several "edge effects".
Hello Souad Neffar,
during my research I found that "edge effect" is a rather vague term. I don't like it as most things we are dealing with are gradients. I tried to summarise several definitions in my paper. I'll attach it.
Besides that, there you can find that there is more on edge effects than species...
Cheers,
Martin
Hello,
I agree with Martin that "edge effect" is a very vague term used for many very differents ecological phenomenons. However, what is behind that is that when you have a discontinuity of any variable (especially land cover), many ecological processes are influenced by the distance to the discontinuity. You may want to avoid this influence by sampling far from the discontinuity (boundary between 2 land cover), or you may want to study it, or you may want to take it into account.
Cheers
I will read it and give you my opinion .
Thank you Marc,
Thank you Martin.
Cher Marc,
Souvent, sur térrain, la limite entre 2 parcelles, par exemple, une parcelle cultivée et autre boisée est de quelques cm. Par définition , cette zone de transition ( une ligne) est théoriquement caractérisée par de brusques variations des conditions abiotiques et une richesse spécifique, sous l'influence de "l'effet -lisière". Est ce possible qu'au niveau d'une ligne ou une bande de quelques cm qui sépare deux habitats différents, les conditions abiotiques diffèrent et la richesse specifique soit elevée? Ou bien est ce que, c'est en rapport avec la largeur de la zone qui sépare les 2 types d'habitat?
Merci.
Bonjour,
Cette ligne est la "bordure", elle sert de point de référence arbitraire pour mesurer des distances. L'effet de lisière, c'est que certaines variables varient en fonction de la distance à cette bordure, alors qu'à l'intérieur des parcelles, assez loin de la bordure, les mêmes variables varient mais de façon indépendante de cette distance. La zone de lisière est la bande dans laquelle on a cette relation à la distance à la bordure. Par exemple: la végétation peut être de moins en moins dense au fur et mesure qu'on entre dans un bois depuis sa bordure externe. Lorsque la densité se stabilise, on est sortit de la zone de lisière. La thèse d'Audrey Alignier explique cela très bien.
Cordialement
Article Distribution des communautés végétales sous l'influence des ...
Bonjour,
Profondément, merci. J'ai bien saisi à présent, n’empêche que je vais lire la thèse.
Cordialement.
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