Fire in Landscape Management in Germany: The Kaiserstuhl Area in Baden Württemberg State
A research and development project of the Fire Ecology Research Group, Max Planck Institute for Chemistry, Biogeochemistry Department, c/o University of Freiburg, supported by the Ministry for Rural Space (Ministerium Ländlicher Raum) Baden-Württemberg State, Germany. Phase I (1997-2000).
Background and the problem
The majority of protected areas in Germany are not of pristine nature. They are embedded in landscapes that have been shaped by land-use systems over centuries. These systems historically involved processes such as burning, grazing, mowing and cutting which transformed natural landscapes to unique ecosystems. These ecosystems provide habitats for many plant and animal species which are under protection today, including many endangered (red list) species. The recent socio-economic developments, however, resulted in structural changes of the rural space. Many agricultural sites are treated less intensively or are abandoned because farming is no longer profitable. As a result human-made open ecosystems are lost. Without disturbance secondary succession leads to a tree- and shrub-dominated vegetation form which is the potential natural vegetation type in most parts of central Europe. As a result, many plant and animal species adapted to or found in these ecosystems will face the threat of extinction.
If the maintenance of these abandoned ecosystems is desired, it is necessary to introduce substitute-disturbance processes into these areas to maintain the dynamics of processes which have shaped these landscapes historically.
To ameliorate the problem, several options can be taken into consideration. These options include traditional mowing, grazing, cutting practices, and the use of fire as a vegetation management tool. Mowing, grazing and cutting are already being practiced in nature conservation in Germany. But the lack of financial and personnel resources, including the loss of skill and expertise, limits the use of these practices. Thus, alternative approaches are needed. Prescribed burning could offer a potentially efficient and relatively cheap tool to achieve the land management objectives of the areas in question.
This aim of the research project is the investigation of the application of prescribed burning for maintaining the traditional open meadow-type vegetation structure on slope sites which are threatened by secondary succession.
The study area
The study is currently conducted in the Kaiserstuhl area, an old volcano fragment dating back to the Tertiary located in the Rhine valley in southwest Germany. Most of the lower parts are covered by an up to 16 m-deep loess layer. The history of wine cultivation in the area dates back to the 8th century. Since then farmers grew wine on terraces built on the hilly terrain. The traditional vegetation cover on the slopes between the terraces was of a meadow-like grassland.
The problem: Changing of the treatment of the slopes
Altough the natural vegetation cover in the area is of a bush- and tree-dominated forest type, vineyard slopes have a distinct vegetation cover dominated by grass. These ecosystems were maintained by mowing and occasional burning until World War II. After the war the area experienced a dramatic increase in wine growing and sharp decrease of animal husbandry with its associated mowing and cutting practices. As the farmers no longer needed the hay as the winter food for their cattle, they began to burn the slopes in winter so as to suppress the growth of bush and tree species in order to maintain open vegetation structure:
In 1975, following the Federal German nature conservation law, the State of Baden Württemberg imposed a ban of the free burning (broadcast burning) of vegetation. Since then the slopes were cultivated only in some exceptions. The consequence was the ever increasing expansion of bush and trees into these areas due to secondary succession. This has resulted in the decrease or loss of habitats for many plant and animal species that are adapted to or found in these ecosystems, and require more light and higher ground temperatures, conditions that prevail in open ecosystems:
The slopes in the old historical vineyards were only up to 8m high. But with the consolidation and restructuring of farmland property in the 1960s and 80s, bigger slopes of up to 40 m high and with over 100% inclination were constructed. Except for the initial grass layer establishment on the slopes, no human intervention has taken place in the area. Today, both the new and the historical slopes serve as a medium for secondary succession to run its course. Given the extent of the area (4 km2 only in the central part of the Kaiserstuhl area), a great amount of time and money is required to maintain the traditional grass-dominated open structures by cutting and/or mowing. As an alternative, this project proposes the use of prescribed burning to achieve the objectives set for the area:
The project was undertaken to determine whether prescribed burning of small plots in late winter could be used to maintain and promote the traditional open vegetation structure, the habitats and occurrences of typical and characteristic animal and plant species on the slopes of the vineyards of the Kaiserstuhl area. Three project studies are conducted:
Effects of different fire types on the composition, structure and distribution of the vegetation types of the open, meadow-like ecosystems; response of some typical species which immigrate and extend since the beginning of the succsession-period 20 years ago; and temperature and soil moisture regimes on burned and unburned plots.
Earlier investigations conducted in the 1980s on the slopes of the Kaiserstuhl area indicate that animals (mainly arthropoda) in the grass-layer are killed by fire in the wintertime. Individuals which are in or on the ground survive normally. However, since the burned plots are relatively small and surrounded by unburned plots the immigration rate after the fire is very high and takes place very rapidly. Therefore it is just a temporary shift of populations, but no sustainable change in the species composition (Lunau and Rupp 1988). In this project, the direct and indirect effects of fires on snails is investigated. The snails populations serve as indicators for the rate of spread of the reconolisation of the area after fire.
The socio-economic part of the research aims for a comparison of the costs of different management strategies (burning, mowing, other mechanical treatment such as mulching, succession), the developement of for a slope management plan, an public relations for the public acceptance of prescribed burning
Fig. 1. On this test site the vegetation response to different fire types and fire frequencies is investigated on eight permanent plots (1 m2 each). The recording is done by a frequence-frame which is subdivided in 16 sub-squares. Furthermore the spread of Clematis vitalba and Rubus caesius is documented. Photograph taken in July 1997.
Fig. 2. Burning of the same slope in January 1998 by an uphill-running headfire. The red-white sticks are used to detemine the rate of fire spread.
Fig. 3. The same slope immediately after burning. The typical mosaic of burned and unburned patches produced by prescribed burning is clearly seen. Unburned patches are important for the recolonisation by animals.
Fig. 4. Burned (left) and unburned (right) portions of the test site in early spring 1998 which can easyly be distinguished: Burned parts appear in a light green. This is the result of the combustion of the dead grass lcover which acts as an efficient temperature-insulating layer and delays the vegetation period for about two or three weeks.
Fig. 5. In July 1998 no significant difference in the grass-layer vegetation could be observed in the burned and unburned plots. Neither the species composition nor the structure showed a significant difference. The inventory of tree and shrub species shows that only young shoots (diameters <3cm and lengths up to 30 cm) are killed by fire. Species and individuals that are older than 3 to 5 years and able to resprout (coppice) survive the fire.
Lunau, K. and Rupp, L. (1988): Auswirkungen des Abflämmens von Weinbergsböschungen im Kaiserstuhl auf die Fauna. – Veröff. Naturschutz Landschaftspflege Bad.-Württ. 63; 69-116.
Mr. Hans Page Project Leader, Fire in Nature Conservation and Landscape Management Fire Ecology Research Group / The Global Fire Monitoring Center c/o Freiburg University PO Box D-79085 Freiburg GERMANY e-mail: firstname.lastname@example.org