Ammann Brigitta
Palaeoecological investigations of pasture woodland in Combe des Amburnex, Swiss Jura Mountains
Project Number: CH-4963
| Project Type: |
Dissertation |
| Project Duration: |
09/01/2002 - 07/31/2005 project completed |
| Funding Source: |
other , |
| Leading Institution: |
Institut für Planzenwissenschaften, Universität Bern |
| Project Leader: |
Prof. em. Brigitta Ammann
Phone: +41 (0) 31 631 49 21
e-Mail: brigitta.ammann(at)ips.unibe.ch
|
Research Areas:
Disciplines:
Abstract:
The Jura Mountains are situated along the border between Switzerland and France. In the high western part of the mountain chain the vegetation consists of a patchwork of forests, open pastures and wooded pastures, a mosaic that in all makes up a pasture woodland. The trees are dominated by spruce (Picea), with fir (Abies), beech (Fagus) and a few scattered maples (Acer) growing in less grazed areas. This special landscape has been created by centuries of summer grazing and forestry practices. It is thus a cultural landscape, to a large degree dependent on human activities and management decisions.
The mix of pastures and forests gives the landscape special values apart from the purely economic. Historically the landscape can be seen as a reminiscence of an earlier much more widespread occurrence, thus giving it a cultural-heritage value not only for the region but for large parts of Europe. The variation and moderate disturbance of the vegetation favours biodiversity and may create a special habitat for some rare species (e.g. Lobaria pulmonaria and Saxifraga hirculus). The open pastures with scattered spruce trees trimmed by grazing cattle also creates a park-like appearance beloved by hikers, cross-country skiers and Sunday picnickers.
Within the framework of NCCR Plant Survival sub-project 6 (Pattern and long-term changes in pasture-woodlands: Complex plant-herbivore interactions in a traditional type of agro-forestry) the thesis project was launched as part of an effort to gain a better understanding of the processes that create and maintain pasture woodlands, with the practical goal of improving future management plans in a changing economic and natural environment. The specific goal for the thesis project was the long-time development and the vegetation history of pasture woodland as recorded in natural archives like peat deposits. The results are of independent value but are primarily planned for the larger project.
The small mountain valley Combe des Amburnex (1300 m a.s.l.), 12 km NW of Lake Geneva, was chosen as the investigation area. Three peat profiles 1 km apart were extracted in 2002, two from a large mire in the valley bottom (Sèche de Gimel) and one from a small mire up the valley side (Les Amburnex, 1370 m a.s.l.). The pollen content and other properties of the peat were stratigraphically analysed, allowing an estimation of past vegetation cover and its changes. The short distance between the peat profiles allowed better spatial resolution than would otherwise be possible. The lowland pollen transported from a long distance were similar for all three peat profiles and could be used for internal correlation. Other sites from the Alps have been included for comparison and establishment of general trends.
Several pasture expansion and forest regeneration phases have occurred in Combe des Amburnex during the past 2000 years. The central part of the valley gained its modern open appearance c. AD 1200, while the pasture woodland in the landscape as a whole came into being c. AD 1700. The creation of pasture woodland is clearly associated with fire activities, and charcoal production or similar activities may have played a major role in the opening of the landscape. The forest in the first millennium AD was made up of equal parts spruce, fir and beech. From the end of the same millennium spruce started to become more dominant, possibly an effect of long-time forest grazing and creation of wooded pastures. The large deforestations around AD 1700 increased the groundwater table and re-initiated peat growth in some of the mires. The mires have also been severely affected by grazing, a phenomenon that can be seen across the Alps.
The landscape structure has thus been rather stable during the past 300 years and remains so under the current land-use regime, but changes in nutrients, grazing–pressure and climate during the 20th century have had an increasing effect on the species composition.
Publications:
Sjögren P, Lamentowicz M. 2008. Human and climatic ipact on mires: a case study of Les Ambrunex mire, Swiss Jura Mountains. Vegetation History and Archaeobotany 17:185-197
Sjögren Per. 2006. The development of pasture woodland in southwest Swiss Jura Mountains over 2000 years, based on three adjacent peat proviles. The Holocene 16:210-223.
Sjögren, Per J.E. 2005. Palaeoecological investigations of pasture woodland in Combe des Amburnex, Swiss Jura Mountains. Dissertation Universität Bern.
pdf Thesis
Last update: 5/18/18
Source of data: ProClim- Research InfoSystem (1993-2024)
Update the data of project: CH-4963
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