Tölz moor axis

In the environmental atlas you will find a representation of the moors with a legend.

Peatlands in the environmental atlas

Climate protection through the preservation of moors in the district of Bad Tölz-Wolfratshausen

Elisabeth Pleyl, specialist for peatland restoration at the Bad Tölz-Wolfratshausen district office

Bogs are formed when plant growth is deposited due to heavy moisture and preserved as peat. Drainage of peatlands, on the other hand, leads to aeration and subsequently to aerobic decomposition of the peat.

Restoring the water balance to renature raised bogs (felting) saves around 15 tons of CO2 equivalents per hectare per year by preserving the peat substance, and around 30 tons of CO2 equivalents per hectare per year in connection with grassland extensification (DRÖSLER 2009 and 2012). In addition to carbon dioxide, methane and nitrous oxide are the greenhouse gases occurring in peatlands. They are included in the calculation of climate-relevant trace gas flows in accordance with their effectiveness. To represent the sum of the gases, they are referred to as carbon or CO2 equivalents.

Since 2008, the Free State of Bavaria has been providing funding for peatland restoration measures through the Bavaria 2050 - Peatlands climate program.

The district of Bad Tölz - Wolfratshausen is responsible for land acquisition or the registration of easements if owners wish to make their moorland available for renaturation.

Since the first renaturation measures were carried out in the district in 1993 by various organizations (private individuals, nature conservation associations, clubs, the district, Bavarian State Forests, the Free State of Bavaria), around 400 hectares of moorland have been renaturated according to plan, thus enabling effective rewetting on around 280 hectares. In addition, 248 of the 306 raised bog areas in the district of Bad Tölz - Wolfratshausen are still in an ecologically valuable condition and worthy of preservation, making them particularly suitable for renaturation. They cover a total area of over 2,000 ha.

Status: 09/2024

The peatland restoration work carried out in the district on around 372 hectares to date has reduced total annual greenhouse gas emissions by over 6,700 tons of CO2 equivalents. This reduction can be increased fivefold on the 2,000 ha of non-agricultural raised bogs alone.

At the same time, peatland restoration has effects that benefit society as a whole: rare habitats of endangered plant and animal species are preserved, the restoration of the peatland's own water balance has a positive effect on groundwater and surface water, including the capping of flood peaks.

Literature:

DRÖSLER, M. (2009): What do peatlands have to do with the climate? - In: Laufener Spezialbeiträge 2/09: 60 - 68.

Climate protection through peatland restoration

Prof. Dr. rer. nat. Matthias Drösler

Peatland restoration measures can make a relevant contribution to climate protection. However, the scale depends on the emissions reference value on the one hand and on the areas available for renaturation on the other. As part of Klip2050, Bavaria has pioneered a major peatland restoration program for climate protection, which is currently being implemented. Based on the current state of knowledge, the following applies to climate relief through peatland restoration: damming is better than flooding and many small measures that can bring the water level close to the surface are better than a few large measures that flood areas while leaving others dry.

Peatlands are relevant ecosystem types for climate protection. Peatlands store around 550 billion tons of carbon worldwide, which has been removed from the atmosphere as CO2 since the last ice age. This carbon can be released again as CO2 through drainage and climate change. The emissions caused by intensive land use of German peatlands correspond to approx. 4.5 - 5 % of Germany's total fossil emissions. If peatland restoration is specifically geared towards climate protection and water levels are managed sensitively, a significant contribution to climate relief can be achieved. Reduction potentials in rain moors are 15 t CO2-equiv. ha-1 a-1 and in groundwater moors 30 t CO2-equiv. ha-1 a-1.

The functional principle of peatlands is carbon sequestration. Under undisturbed conditions, peatlands are the only type of ecosystem that continuously and permanently absorb significant amounts of carbon. This distinguishes them from both mineral soils and forest ecosystems. Worldwide, the carbon content of peatlands is estimated at 550 Pg C, which corresponds to around 30% of the world's soil carbon on just 3% of the earth's surface. Preserving these carbon reservoirs is preventive climate protection. Drying out leads to a release of the carbon bound in peatlands.

However, it is not the risk posed by mineralization of the C pool that is decisive for climate relevance, but the current balance of the exchange of climate-relevant trace gases: CH4 (methane) is emitted in near-natural peatlands in parallel with the binding of CO2 (carbon dioxide). If the peatlands are drained and used, CO2 and N2O (nitrous oxide) are emitted due to aerobic peat decomposition, whereby the natural CH4 emissions decrease. The ratio of the fluxes together with the GWP (global warming potential) of the individual gases determines the climate impact. Therefore, estimates of the effect of land use measures on climate protection can only be made reliably if the fluxes of all three climate-relevant trace gases (CO2, CH4, N2O) are recorded.

Current state of knowledge on trace gas exchange and peatland restoration

1. effect of different site conditions on trace gas exchange

The dominant controlling factor in peatlands, which affects both the type of vegetation and the exchange of trace gases, is the water level. In near-natural situations with average annual water levels just below the ground surface (approx. -10 cm), the conditions are right for peat-forming vegetation types such as colorful peat moss lawns or cotton grass stadia in raised bogs. Under these near-natural conditions, gross primary production (GPP) outweighs ecosystem respiration (Reco), making the annual balance of net ecosystem exchange (NEE) negative, i.e. uptake into the system takes place. Under these near-natural conditions, CO2-C uptake of over 100 g C m-2 a-1 is achieved in rain moors at the edge of the Alps (see DRÖSLER 2005). At the same time, however, the system loses considerable amounts of CH4. This can be up to approx. 30 g CH4-C in near-natural rain bogs (ibid.). The current carbon balance of near-natural rain bogs thus still shows a significantly higher uptake than the stratigraphically determined long-term average since the formation of the bogs (LORCA: Long term rate of carbon accumulation). If the water level is now moderately lowered or an exceptional drought occurs, the arrow of net ecosystem exchange is reversed, i.e. ecosystem respiration outweighs gross primary production. This occurs because under aerobic conditions the mineralization of the peat is about one power of ten faster than under anaerobic conditions. Methane emissions fall to an insignificant level and their direction is no longer clearly defined. On the other hand, nitrous oxide emissions are increased because the conditions favorable for denitrification (sufficient soil moisture and proximity of aerobic and anaerobic zones) are now beginning to set in. If the sites are renaturalized, they are transferred from more or less stable conditions (near-natural and degraded) to dynamic development. Depending on the type of renaturation, existing vegetation, speed of succession, dynamics of the water table, etc., the material flows change quickly. Reco can be drastically and more or less immediately reduced by raising the water level. On the other hand, the development of an efficient GPP depends on how quickly peat-forming vegetation is established. In the case of sphagnum grasslands in rain bogs, this can be achieved in just a few years. The development of pure calcareous sedge meadows, on the other hand, can take several decades. However, only when the vegetation-dependent GPP is greater than the Reco does the stand act as a CO2-C sink. On the other hand, the CH4 flux increases to a near-natural level, whereas N2O emissions are eliminated. In a waterlogged variant, as in the waterlogged variant, the uptake or release of CO2 depends on the precursor vegetation and the development speed and direction of the succession processes of the vegetation. However, the emissions of CH4 will increase considerably as a result of overdamming and reach more than 300 g CH4-C m-2 a-1 in groundwater bogs, which is far above near-natural conditions.

2. carbon footprint vs. climate effectiveness

The rainforest peatland sites of the exemplary results from the Kendlmühlfilze are structured along a naturalness gradient between the two axes of carbon accumulation (C balance) and climate impact (GWP balance). The meteorological convention that negative numbers represent a loss for the atmosphere and a gain for the ecosystem is adopted. It is striking that the degraded site/vegetation types act both as carbon loss areas and as climate warmers. The near-natural areas, on the other hand, act as carbon sinks on a scale that corresponds to 2-3 times the long-term average carbon sequestration (LORCA) with an average of approx. 100 g C m-2 a-1 (DRÖSLER 2005). On the other hand, these sites are still slight climate warmers. In general, it can be assumed that the near-natural sites are close to climate neutrality. Compared to the degraded sites, the near-natural sites act as a considerable climate relief.

3. determination of the climate relevance of peatland sites using simple indicators

Now that the water level has been identified as the dominant factor for the exchange of climate-relevant trace gases, the question arises as to whether there is also a quantitative relationship between mean water level (MW) and the climatic effectiveness of peatlands. This relationship was examined using the data set from the Kendlmühlfilze. It is noticeable that there is an optimum range at which the climatic effectiveness is lowest: approx. -5 to -10 cm MW. If the water level rises to the top edge of the terrain or is flooded, the climatic effectiveness increases again. Management recommendations for peatland restoration can be derived from this. However, these values only represent one point in time in a dynamic development after renaturation. For this reason, an LfU project is investigating the extent to which the climate balance has changed on exactly the same areas 10 years after damming and a temporal component can be included in the relationship between water level and climate relevance. This is crucial for the prognosis of climate relief through renaturation.

4. how high is the reduction potential through peatland restoration?

If peatland restoration is carried out optimally from a climate protection perspective, reduction potentials of approx. 15 t CO2-equiv. ha-1 a-1 can be achieved for rainwater peatlands and approx. 30 t CO2-equiv. ha-1 a-1 for groundwater peatlands (see FREIBAUER, DRÖSLER et al., 2009). This presupposes that renaturation is started from the most polluted levels (intensive grassland and arable land use) and that target stands can be established with average water levels just below the surface (-10 cm). In contrast, overwatering variants in groundwater bogs can even exacerbate the pollution situation because the considerable methane emissions overcompensate for the reduced carbon dioxide emissions in terms of their climate impact (see AUGUSTIN & CHOJNICKI 2008). According to our own calculations, a maximum reduction potential of 35 million tons of CO2 equivalents was determined for Germany through peatland restoration.

Prof. Dr. rer. nat. Matthias Drösler, Weihenstephan-Triesdorf University of Applied Sciences (HSWT)

Bibliography:

AUGUSTIN, J. & CHOJNICKI, B. (2008): Exchange of climate-relevant trace gases, climate impact and carbon dynamics in the first years after rewetting of degraded fen grassland. In: GELBRECHT, J.; ZAK, D. & AUGUSTIN J. (eds.): Phosphorus and carbon dynamics and vegetation development in rewetted peatlands of the Peene Valley in Mecklenburg-Western Pomerania. Reports of the IGB, Issue 26/2008, pp. 50-67.

BYRNE, K.A.; CHOJNICKI, B; CHRISTENSEN, T.R.; DRÖSLER, M.; FREIBAUER, A. et al. (2004): EU peatlands: Current carbon stocks and trace gas fluxes. CarboEurope-GHG Concerted Action - Synthesis of the European Greenhouse Gas Budget, Report 4/2004, Specific Study, Tipo-Lito Recchioni, Viterbo, October 2004, ISSN 1723-2236.

DRÖSLER, M. (2005): Trace gas exchange and climatic relevance of bog ecosystems, Southern Germany. Dissertation at the Technical University of Munich, 179 p. published online: urn:nbn:de:bvb:91-diss20050901-12494310.

DRÖSLER, M.; FREIBAUER, A.; CHRISTENSEN, T. & FRIBORG, T. (2008): Observation and status of peatland greenhouse gas emission in Europe. In: The Continental-Scale Greenhouse Gas Balance of Europe. DOLMAN, H.; VALENTINI, R. & FREIBAUER, A. (EDS.): Ecological Studies , VOL. 203 2008, 305 P. ISBN: 978-0-387-76568-6.

FREIBAUER, A.; DRÖSLER, M.; GENSIOR, A. & SCHULZE, E.-D. (2009): The potential of forests and peatlands for climate protection in Germany and on a global scale. Nature and Landscape. Issue 1/2009. special issue on biodiversity and climate change. pp. 20-25.

In the Tölzer Land region, many of the wetlands, which are among the best preserved in Central Europe, are nevertheless in a critical ecological condition.

For years, the Benediktbeuern Monastery's Center for Environment and Culture, the Landesbund für Vogelschutz, the Bund Naturschutz, the farmers' association, the district of Bad Tölz-Wolfratshausen, the government of Upper Bavaria and many others have been involved in the renaturation of individual moors.

Rewetting measures in the Spatenbräu and Eglinger felts, in the Höfner Filz and in the Loisach-Kochelsee bogs are enabling a return to their former beauty and allowing cotton grasses and butterflies such as the raised bog yellow butterfly to recolonize their original habitat.

The experience gained over the years led to the idea of renaturalizing the moors on a large scale, systematically and in order of ecological importance.

The founding group Tölzer Moorachse (2003) consisted of (from left to right:)
Manfred Nagler (former District Administrator of Bad Tölz-Wolfratshausen), Father Karl Geißinger (Center for Environment and Culture Benediktbeuern e.V.), Roland Weid (Higher Nature Conservation Authority), Elisabeth Pleyl (Area Manager ZUK), Isidor Fischhaber - not pictured - Alois Schuller (Bavarian Farmers' Association Birgit Weis (Higher Nature Conservation Authority)), Elisabeth Pleyl (Area Manager ZUK), Isidor Fischhaber (not pictured).), Roland Weid (higher nature conservation authority), Elisabeth Pleyl (area manager ZUK), Isidor Fischhaber - not in the picture - Alois Schuller (Bavarian Farmers' Association), Birgit Weis (area manager Landesbund für Vogelschutz), Dr. Klaus Schröder (district chairman LbV), Achim Rücker, Carola Belloni (Bund Naturschutz), Joachim Kaschek (lower nature conservation authority ) and - not in the picture - Alfred Ringler (Dip.biologist)

The Tölzer Moorachse steering group currently includes:

(from right to left.) Josef Niedermaier (District Administrator of Bad Tölz-Wolfratshausen), Father Karl Geißinger (ZUK), Peter Fichtner (District Chairman BBV, now represented by Benedikt Zangl - not in the picture), Walter Wintersberger (Chairman of the LBV District Group Bad Tölz-Wolfratshausen), Achim Rücker (BN Bad Tölz-Wolfratshausen), Elisabeth Pleyl, Birgit Weis (area supervisors of the LBV/ZUK), Franz Steger (lower nature conservation authority at the Bad Tölz-Wolfratshausen district office), Veronika Feichtinger (higher nature conservation authority at the government of Upper Bavaria). Not in the picture: Alfred Ringler (certified biologist)

The two area managers Elisabeth Pleyl and Birgit Weis from the district were honored together with their 41 colleagues on 2 June 2017 by Dr. Christian Barth, Head of Office at the Bavarian State Ministry of the Environment and Consumer Protection. When handing over the certificates, Dr. Barth emphasized that the area managers put their "heart and soul" into nature conservation.

The 'Area management in Bavaria' project looks after selected landscape areas from the high altitudes of the Alps to the hills of the Long Rhön, from the forests of the Bavarian Forest to the shores of Lake Constance.

The area managers in the district look after the moors and the Isar. They are committed to their protection, maintenance and development. With eleven percent moorland area, the district is one of the top performers in Bavaria. Renaturation projects are selected together with the 'Tölzer Moorachse' working group, in which environmental associations, the district administrator, nature conservation authorities and a representative of the farmers discuss the requirements in the area and during implementation. Over the past 30 years, around 800 hectares of moorland have been restored by stakeholders in the district. Around the same amount of moorland, which has been continuously drained by ditches for 100 years or more, is still the focus of renaturation. Moorland restoration helps to protect the climate because wet moors store carbon and can also store high summer precipitation on site and only release it slowly and at a reduced rate. But the rare plants and animals of the raised bogs, such as cotton grass, sundew, dragonflies and many more, also benefit from rewetting.

The area managers also conduct excursions and document selected animal and plant species. These include the German tamarisk - a shrub that is threatened with extinction and only occurs in parts of wild rivers such as the Isar.

Walter Wintersberger, chairman of the LBV district group, and ZUK rector Father Geißinger, both responsible for the area management in the district, are impressed by the award. "I am pleased that we have had good cooperation in the preparation and implementation of peatland restoration in our district for 14 years thanks to the area management. This enables us to make a decisive contribution to the preservation of near-natural moors," says Father Geißinger.

Contact persons:

• Birgit Weis, Area Manager Loisach-Kochelsee-Moore and Isar, Landesbund für Vogelschutz in Bayern e.V., moore.isar.gebietsbetreuung (at) lbv-toel.de
• Elisabeth Pleyl, Area Manager Loisach-Kochelsee-Moore, Center for Environment and Culture Benediktbeuern, elisabeth.pleyl (at) zuk-bb.de

Elisabeth Pleyl
Dipl.-Ing. Landespflege
Area manager Loisach-Kochelsee-Moore
Owner: Center for Environment and Culture (ZUK) Benediktbeuern
Tel. 08857/88705 (Monday, Tuesday)
Email: elisabeth.pleyl [at] zuk-bb.de