Contexte environnemental et colonisation végétale des moraines récentes

• Published in: Norois
• Main Author: Moreau, Myrtille
• Format: Article in Journal/Newspaper
• Language: French
• Published: Presses universitaires de Rennes 2008
• Subjects: analyse de données; marge proglaciaire; mésoclimat; data analysis; proglacial area; geo; envir; Arctic; Edithbreen; Svalbard; Arctique*; glacier; Spitsberg
• Online Access: http://journals.openedition.org/norois/647

In relation with the present global climatic change following the Little Ice Age, most of the Arctic Glaciers are retreating. Therefore, larger and larger areas become free for plant colonization. Such processes can be observed on Svalbard where the present study takes place; on the front areas of two glaciers (named Edithbreen and Austre Lovénbreen). Both of them are located on the Brøgger peninsula, (79° N); the first one is South facing whereas the second one is North facing. The sites were sampled and systematic botanical releves have been made, aiming at explaining the relationship between ice melting and plant colonization process. Time is, of course, the main control which determines the vegetation evolution in term of physionomy and floristic composition. The phanerogams start to colonize the moraine 20 years after the glacier has left. Everywhere, the floristic sequence is the same from the early pioneer stages until the mature ones. However, this process is not homogeneous and not only time-dependent. The environment conditions are also important and their effect can be shown at different scales. For instance, the south and north facing positions can be recognized as factors which force variations in the colonization process. Obviously, the local conditions are interfering with the general time dependent colonization process. Sous l’effet du réchauffement climatique qui a suivi le Petit Âge Glaciaire, la fonte des glaciers arctiques a libéré de nouveaux espaces conquis ensuite par la végétation. Le phénomène est bien marqué au Svalbard où la présente étude est conduite. Celle-ci concerne les marges de deux appareils, les glaciers Edithbreen et Austre Lovénbreen le premier est situé en façade sud, l’autre en façade nord de la presqu’île de Brøgger (79° N). Une analyse par relevés floristiques systématiques permet de mettre en relation les phases successives de retrait glaciaire et de colonisation végétale. Le temps est évidemment le facteur déterminant qui gouverne l’évolution de la végétation tant ...