Projects

Mire renaturation Münsinger Filz

At 73 ha, the Münsinger Filz is the largest felt in the surrounding area. Further to the north, only the Allmanshauser and Bachhauser Filz are located in the Würmmoräne moorland band, while further to the northeast the Deininger Filz completes the moorland before the beginning of the Munich gravel plain. The Münsinger Filz was therefore selected as a project area by the 'Tölzer Moorachse' steering group due to its size and representation, site and species diversity.

Just over ¾ of the owners have made their land available for moorland restoration. The measures were very well received by the vast majority of owners, as well as by representatives of the municipality and farmers.

Between 1830 and 1860 there was a shortage of wood for many people, so they began to cut peat.

An elderly gentleman can still remember the drainage work in 1922; he also still has an invoice from the cooperative that was founded for the purpose of drainage and which, with the help of prisoners of war, dug long drainage ditches to enable a better peat yield. Nevertheless, the peat trenches and ditches were soon left to themselves again, as the drainage did not bring the desired success.

In the 1960s, peat was still cut, and later the sparse growth was used as bedding in stables, after which the land was abandoned.

Even today, the ditches left to their own devices still draw water from the moor and, contrary to what is often assumed, they do not grow over completely on their own. As a result, the burning of the peat continues more or less unnoticed in the form of 'cold burning'. The peat - the mass of plants that has grown in the bog over thousands of years, originally preserved by moisture and only partially decomposed - is becoming less and less. Soil organisms consume the now dry peat, which accounts for up to 98% of the dry mass in raised bogs, and break it down completely into carbon dioxide. The moor therefore loses 1 decimeter in height in 10 years.

The water retention in the peat ponds and ditches creates habitats for dragonflies and amphibians, the conditions for reptiles and butterflies are also improved, peat mosses can grow, and typical species of raised bogs such as the white cottongrass with its shining white seed heads or the rosemary heather are preserved and can spread.

E. Pleyl

Königsdorfer Weidfilz renaturation project

Fig. 1: Königsdorf pasture felt (B. Weis)

Area description

Before the large-scale extraction and cultivation activities, the moors around Königsdorf were among the largest raised bog complexes on the entire Swabian-Bavarian plateau. At around 250 hectares, the Weidfilz is the largest remaining raised bog. Due to the size of this area, it is classified as a moorland area of state-wide importance (StMUGV 1997). Apart from Article § 30 BNatSchG, it is not subject to any other protection status.

Fig. 2: The pasture felt is located approx. 500 m west of the village of Königsdorf on the state road 2064

Source: ATKIS® DTK200-V, © Federal Agency for Cartography and Geodesy 2003

Fig. 3: Extent of the moors around Königsdorf, Bay. Royal Surveying Office 1812

The pasture felt was used intensively. Industrial peat extraction took place for a few years after the First World War (peat coke production) and again for a few years after the Second World War. Peat was then extracted by hand until around 1970. Three large excavator trenches (up to 50 m wide) and an extensive system of slit trenches run through the raised bog today. In some areas, woodland cover has increased considerably due to drying out and mineralization. The peat body has shrunk by about 1 meter in 50 years. Despite these impairments, the Königsdorfer Weidfilz still has large open raised bog areas and very good conditions for renaturation.

In 1909, a sword from the Bronze Age was found in the pasture felt during peat cutting, which can now be seen in the Museum of Prehistory and Early History in Munich.

Significant animal and plant species

Birds: whinchat, stonechat, woodcock, snipe (migration)

Insects: Dragonflies, e.g. damselflies, Siberian damselfly, Arctic emerald dragonfly and butterflies, e.g. marsh meadow butterfly and edge-ringed damselfly

Reptiles: Adder

Plants: sundew, rosemary heather, bell heather, flowering rush

Nature conservation goals

The Weidfilz was selected by the Tölzer Moorachse steering group as a reference moor for renaturation in the district. After extensive persuasion of the 11 owners, including the municipality of Königsdorf, an area of around 20 hectares was rewetted. The district was responsible for the project and the Landesbund für Vogelschutz in Bayern e.V., Kreisgruppe Bad Tölz-Wolfratshausen (LBV) was entrusted with the technical implementation. A total of around 300 peat walls were made to close the slit trench system. The work was completed after just 3 weeks and peace returned to the area.

Fig. 4: Partial trench damming by peat walls, Maxl construction company, Eurasburg

In 2008, a litter meadow on the edge of the raised bog was acquired by the LBV, which was cleared of bushes by active members and now serves as a habitat for rare butterflies again.

In order to continue the project, it was necessary to obtain precise knowledge of the area. A comprehensive renaturation plan was drawn up by the LBV on behalf of the State Office for the Environment. The implementation of the proposed measures depends on the willingness of the private landowners. For this reason, the LBV area manager and the moorland protection officer at the Lower Nature Conservation Authority are carrying out extensive persuasion work. As part of the StMUGV's 2020 climate protection program, around 15 hectares of moorland have been secured (purchase by the district and easement).

A continuation of the renaturation under the supervision of the Tölzer Moorachse steering group and with financial support from the NABU Moorschutzfonds Deutschland is to be carried out soon on around 60 hectares.

Birgit Weis,
Dipl.Ing. Forstwirtschaft (FH)
Area manager Loisach-Kochelsee-Moore and Isar
Landesbund für Vogelschutz in Bayern e.V.

The second renaturation project of the Tölzer Moorachse

Due to its high nature conservation value and the ownership structure - most of it is owned by the city of Munich - the Auer Filz was selected as the second project of the 'Tölzer Moorachse' steering group. The 'Tölzer Moorachse' steering group and the area management for the moors in the district of Bad Tölz-Wolfratshausen jointly prepare projects for moor restoration. The areas of application and the procedure for developing the district's extensive moorland landscapes, which are significant throughout Europe, are coordinated with each other from the outset.

The aim of the measure is to safeguard and improve the near-natural raised bog habitat with its diverse functions for the ecosystem - material sink, retention area, preservation of the rare, highly specialized flora and fauna of the raised bog.

Only a few marginal ditches impaired the near-natural state of the Auer Filz. These disturbances had to be remedied in order to counteract the encroachment of Scots pine, spruce and birch from these areas. The measures thus ensure that the purpose of the NATURA 2000 designation, which aims to preserve the extensive moorland areas, is achieved.

Implementation of measures / result:

• Between mid-November 2006 and mid-February 2007, 42 dams were built from undecomposed peat to retain the water. The pure construction time was 7.5 weeks. The peat was removed a few meters from the dam at the level of the headwater. In a few narrow places, where there was no other way of extracting the peat due to the direction of work down the ditch and the complete closure of the navigable terrain, the peat was extracted in the area of the tailwater if necessary. This resulted in artificial 'scours'. For safety reasons, however, they were only made up to 1 m deep so that no traps were created. In any case, there is no risk of erosion due to water run-off:
• To relieve the weirs from flooding, a trough was created by applying pressure or, in the case of large dams, by removing peat with an excavator shovel, which leads around the weir at a large distance.
• The previously removed sphagnums or sods were placed on the dams.

The dams were planned and constructed according to the size of the respective terrain situation.

Photos: Dora Schulze (Weilheim Water Management Office), Elisabeth Pleyl

Renaturation of the Kirchsee felts

The Kirchseefilze are a moorland area located northwest of the municipality of Sachsenkam/Upper Bavaria in the district of Bad Tölz - Wolfratshausen. They are part of the approx. 800 ha Ellbach- und Kirchseemoor nature reserve, which is one of the five most valuable upland and transitional moor areas in the Bavarian Alpine foothills (Arten- und Biotopschutzprogramm Bayern, Bayer. StMLU 1997). The word "felt" is used synonymously with "raised bog" in Bavaria.

In September and October 2012, measures were carried out in the area of the former Kirchseemoor peat works with the aim of renaturalizing the moor and increasing its CO2 absorption capacity. Funding was provided by the Bavarian Climate Program Bavaria 2020 - Moors of the Free State of Bavaria. The district was responsible for securing the land (90% funding was provided through the climate program). The costs for securing the land, planning and implementing the measure amounted to around €376,600.

Support and advice was provided by members of the Tölzer Moorachse. This was the working group's third project after the Königsdorfer Weidfilz (2005) and the Auer Filz (2007).

Fig. 1: Location and extent of the Kirchseemoors (red), the renaturation area is marked in blue (Map: Bayerische Vermessungsverwaltung 2009, modified)

The area

The Kirchseefilze are located in the northern part of the Ellbach and Kirchseemoor nature reserve. As an area of raised bog, they have a special nature conservation value and are of great importance for flora and fauna. As a partially almost untouched and largely wood-free area, heather and moor grass with transitions to rough grassland predominate here, as well as a dense carpet of peat moss on up to 8 m thick raised bog peat.

Fig. 2: The Kirchsee felts (E. Pleyl)

Measures

To restore the moor's own water balance and natural drainage conditions, 378 ditch closures were carried out on an area of around 23 ha. To this end, 37 hectares were made available, including through leasing and sale to the district.

The old slit ditches created for pre-drainage had to be closed by an excavator and large ditches and peat trenches had to be dammed so that peat growth and CO2 storage were possible again in the pre-drained raised bog body.

Fig. 3: Excavator at work closing the trenches in the felt (A. Rücker)

Goals

The endangered animal and plant species of the raised bog benefit from the renaturation of the Kirchseefilze.

The release of water to adjacent bodies of water becomes more even.

The growth of the peat layers is also an important concern:

The release of CO2 from the drained raised bog body is stopped and the bog becomes a CO2 sink again through peat moss growth. The area of 23 ha, which was immediately rewetted, has a carbon sink effect of around 12 t CO2-C or 36 t CO2 per year as a result of the renaturation. In addition, emissions of around 115 t CO2 - C or 345 t CO2 per year are avoided, which would otherwise result from peat decomposition.

First successes

An increase in the water level was observed just two days after the trenches were closed. Dragonflies and amphibians were soon spotted in the newly created damming areas!

Fig. 4: The formerly dry raised bog was successfully rewetted (A. Rücker)

Client for planning: Government of Upper Bavaria
Client for implementation measures: Bad Tölz-Wolfratshausen District Office
Mire expert: Elisabeth Pleyl
Planning, site management: Dipl.-Biol. Achim Rücker
Construction company: Terratop Hobmaier GmbH & Co.KG

The spade brewing felts - and how they were created

The Spatenbräufilze are a raised bog complex influenced by peat extraction and drainage with surrounding litter meadows. They are located in a large depression southeast of Egling in the "Mooshamer Weiher" landscape conservation area. It was once named after the Spaten brewery, which owned the site until 1886. However, it was not until subsequent owners that peat cutting began. Until around 1960, peat was still extracted in peat pits by hand, which was used as fuel peat and also as bedding in stables.

The project

As in many other raised bogs, peat was mined in the Spatenbräufilzen for many years. Drainage was a prerequisite for peat extraction. This drained the water from the typical biocoenoses of the felts. The peat dries out, is better aerated and decomposes.

Drought-tolerant plants, such as heather, spread and bushes and trees settle. Slowly but surely, the once largely open moor becomes a dense forest. As a result, the habitat of the typical raised bog species is becoming increasingly restricted. Without suitable countermeasures, it would eventually be lost altogether.

The species and biocoenoses typical of raised bogs were also in danger of slowly disappearing in the Spatenbräufilzen. Something had to be done.

Renaturation began in 1994. The most important measures were the clearing and rewetting of the heavily drained raised bog core and the networking of open raised bog areas and surrounding litter meadows by removing wooded barriers. The resumption of the use of fallow litter meadows to create flower-rich areas was also a central goal of the project.

The initiative for the project came from the municipality of Egling. Even in the initial phase, private landowners took on the clearing of their land. In the following winters, the Landesbund für Vogelschutz (LBV) continued these measures with numerous volunteers on the land owned by the municipality of Egling: wood barriers between the raised bog and litter meadows were removed and ditches were dammed on the areas that had been cleared of bushes. Work is carried out in winter because snow and frost protect the sensitive moorland soil from major damage. In the summer of 1998, the measures in this part of the Spatenbräufilzen were completed. Work has continued on other areas, for example on the land purchased from the LBV in 1997.

The successes are clear to see: Typical upland moor plants such as the crested cottongrass, cranberry, round-leaved sundew and rosemary heather have spread again.

Financing and organization

Many institutions and individuals contribute to the success of the project: the municipality of Egling as the owner of around a third of the raised bog area, the district of Bad Tölz-Wolfratshausen, the government of Upper Bavaria and the Landesbund für Vogelschutz (LBV). It took over sponsorship of the project in 1995.

Almost all private landowners were persuaded to participate. Technical support also came from Hubert Anwander and Cornelia Siuda. In 1997, the LBV was able to purchase a six-hectare plot of land with financial support from the Bavarian Nature Conservation Fund, the district of Upper Bavaria and the district of Bad Tölz-Wolfratshausen.

Renaturation of the Sonnenhofer Filze

The Sonnenhofer Filze is located south-east of Königsdorf in the district of Bad Tölz - Wolfratshausen. This moor is part of the Königsdorfer Moränen- und Moorplatte, which lies in the southern former Wolfratshauser Seebecken. Due to its size, it is one of the most important moor areas in the Bavarian Alpine foothills.

(Sonnenhofer Filz, southern part)

(Sonnenhofer Filz, northern part)

(Predominance of heather indicates excessive drying out of the raised bog)

Measures

To restore the peatland's own water balance and natural drainage conditions, 34 dams were built in the Sonnenhofer Filz between mid-October and mid-November 2014, covering an area of 14 hectares. Along a deep main ditch up to 2.5 m deep and in eight peat trenches, the ditch closures were installed by a bog excavator. 31 hectares of moorland were made available for this purpose. These areas were leased by the district with the help of funds from the Climate Program 2050 - Moors. The majority of the land was made available free of charge by the owners.

Improving the mowing of the litter meadows in the adjacent fen was also an important part of the renaturation measure. How the raised bog and fen habitats interact is best demonstrated by the rare butterflies, whose caterpillars develop on the plants of the raised bog, while the developed butterfly seeks out the flowers of the litter meadows to find nectar.

(Crawler excavator installing a dam)

Goals

The relatively natural raised bog area of the Sonnenhofer Filz was criss-crossed by several deep drainage ditches and marginal peat trenches as a result of peat extraction and use around 100 years ago. These have mineralized and degraded the peat to this day and the habitat has become increasingly dominated by drought-loving species compared to the near-natural raised bog.

The renaturation promotes the habitat of the rare species of the raised bog. Large brushwood piles were created as habitats for the adder as part of the measure. Trees that die in the future backwater of the ditches are left standing (except for the spruce trees endangered by bark beetles). They will develop into a rare, valuable habitat for a variety of species that only occur in standing deadwood. Surface waters and groundwater recharge benefit from water retention. Above all, the soil and climate are protected by improving the protection of the peat. The release of CO2 from the raised bog body is stopped and the bog becomes a CO2 sink again through peat moss growth. The measures achieve a climate relief of approx. CO2 equivalents/ha x a, thus saving around 69 t CO2 equivalents per year on the approx. 4.6 ha effective area. The bog plants absorb the climate-impacting gas. In the wet environment, the plants are only partially decomposed. The maintenance-free carbon storage 'moor', provided free of charge by nature, starts up again and ensures the permanent storage of carbon without any risks.

First successes

All dams are effective and the water level along the ditches, which previously had the effect of drying out, has now risen to the top of the terrain. The development of the water level is monitored by a series of gauges.

(Dam immediately after construction)

Organization

Support and advice were provided by the members of the 'Tölzer Moorachse' - after a section of the Königsdorfer Weidfilz (2005) and the renaturation of the Auer Filz (2007) and the Kirchseefilz (2012), this is the fourth project of the 'Tölzer Moorachse'.

The district administration of Bad Tölz - Wolfratshausen is responsible for the implementation. Funding was provided by the Bavarian Climate Program Bavaria 2020 - Moors of the Free State of Bavaria. The costs for securing the land, planning and implementing the measure amounted to around €39,000. In addition, extensive preparatory work was carried out by Dipl.-Biol. Achim Rücker of the Bund Naturschutz and by Elisabeth Pleyl, moor specialist at the district office and Loisach-Kochelsee-Moore area manager of the Center for Environment and Culture Benediktbeuern.

A renaturation project of the Bad Tölz-Wolfratshausen district group of the Landesbund für Vogelschutz in Bayern e.V.

Area description:

The glacial moraine landscape in southern Bavaria was once characterized by extensive moorland areas, which were often drained for peat extraction. Raised bogs such as the Eglinger Filz are fed exclusively by rainwater. In Bavaria, they are usually referred to as felts.

With an area of more than 200 hectares, the Eglinger Moors depression is the largest contiguous moor complex in the northern district. Due to the many species that occur and the enormous size of the area, the Eglinger Filz is one of the most important moorland areas in the country.

This moor was not spared from drainage either. From 1960 to 1977, peat was mechanically extracted from the Eglinger Filz. The consequences are still clearly visible today: an approx. 400 meter long peat cut runs through the raised bog area and its southern part has been completely destroyed. Despite these heavy interventions and the gradual drying out, the conditions for rewetting were good, as there was still a thick raised bog body of up to six meters.

The LBV established good contacts with municipalities, authorities and owners during the renaturation of the neighboring Spatenbräufilz. The Schäftlarn Monastery, the largest owner in the Eglinger Filz, was also won over for renaturation.

Biotic communities and habitats worthy of protection:

- Raised bog

- Transition bog

- Litter meadows

- Wet and damp meadows

- Mooshamer Weiherbach

Significant animal and plant species:

Birds: tree pipit, snipe

Insects: Dragonflies such as the large moss dragonfly, small moss dragonfly, small blue darter and butterflies such as the reed devil and meadowsweet fritillary

Plants: shrub birch, rosemary heather, beak reed, sundew, marsh glitterwort

Location of the area:

The Eglinger Filz is located approx. 1 km south of the village of Egling in the district of Bad Tölz-Wolfratshausen.

Status:

partly FFH area 8135-371 "Moore zwischen Dietramszell und Deining" and landscape conservation area "Eglinger und Ascholdinger Filze"

Size of the raised bog:

approx. 55 ha

Nature conservation goals of the LBV:

In 2002, the LBV drew up a comprehensive renaturation plan on behalf of the government of Upper Bavaria and in the fall of 2003, implementation began on almost 40 hectares. The main objective was to restore the natural moor water level by rewetting the approximately six-kilometer-long ditch system. Around 110 peat walls and ten weirs made of logs and peat were created by a moor excavator. The logs were felled at the edge of the moor. In the large peat trench, three massive peat walls (up to 30 meters long) were constructed with precise excavation work to retain the water.

Just a few weeks after rewetting, the ditches were already full of rainwater. The water level has risen significantly since then and the typical raised bog vegetation, such as peat moss, has started to grow again over the years. Experts regard the Eglinger Filz as an outstanding example of successful raised bog restoration in Bavaria.

Two former litter meadows adjacent to the raised bog have been extensively deforested. They are now mowed again annually in the fall and the mown material is used as bedding in stables.

Fescue grassland vegetation has developed in the large peat cut, where the existing dragonfly fauna has been able to spread further.

Further information and links:

LBV district group Bad Tölz: www.lbv-toel.de/Eglingerfilz.htm

LBV lecture on raised bog renaturation in Bavaria: http://ecosurvey.de/Vortraege/Weis_Praktische%20Hochmoorrenaturierungsbeispiele%20BY.pdf

Status: September 2012

Eglinger felt renaturation 2016

The northern part of the Eglinger Filz is characterized by the large open moor landscape, in which there is a peat cut of around 4 hectares, which is rich in standing dead wood. As a result of renaturation measures carried out in 2003, the bog birch trees that had grown up in the peat cut were dammed up and died off. Today they are a valuable habitat for deadwood-dwelling insects, bird species for which they serve as breeding and feeding grounds and many other animals and plants.

In 2003, the dam, which held back the water in the peat pond, was built using only peat according to the state of the art at the time. After a few years, leaks began to appear due to muskrat activity. LBV activists maintained the dam over a period of around 10 years by repairing it by hand.

Through the 'Climate Program Bavaria 2050 - Peatlands' (KliP), the district office prepared the permanent protection of the permeable dam in 2015 by means of a 73 m long sheet pile wall and the construction of six further dams in a neighboring peat trench.

In February 2016, the construction company 'ABE Landschaftspflege' used a tracked excavator weighing just 5 tons and several dumpers to carry out the work on the difficult subsoil without damaging the soil.

Renaturation of the Schemer felt

The Bavarian State Forests are responsible for over 12,000 ha of moorland in Bavaria, which is 9% of all moorland in Bavaria (145,000 ha). Many moor areas have already disappeared forever due to drainage measures in the past. A large proportion of the remaining moors are now more or less disturbed due to drainage.

The restoration of degraded moors is a declared goal of the Bavarian State Forests. The focus is on protecting endangered habitats and endangered species, as well as climate protection by preserving moors as carbon reservoirs.

The Bad Tölz forestry operation has approx. 600 ha of moors (open moors and moorland forests). Since 2005, the company has renaturalized the Mühleckerfilz near Sindelsdorf, the Schemerfilz in the Jachenau, the Schellenbergmoor near Eurasburg and the Gurnmoos on the Benediktenwand. The renaturation of the Schemerfilz was carried out as a compensatory measure specified by the Bad Tölz LRA for various road constructions.

Restoration of the Schemer felt in the Jachenau in January 2009

The 22.6 ha raised bog is located at 725 m above sea level in the LSG 'Hochmoor bei der Schemeralm' and in the FFH area 'Jachenau und Extensivwiesen bei Fleck'. In the species and biotope protection program of 1997, it is listed as an upland moor of national importance and is one of the most striking valley upland moors in the Bavarian Alps. The 2 m - 5 m high raised bog lies on a plateau-like valley terrace above glacial lake clays of the former Jachen reservoir and is bordered to the north by the Jachen and to the south by a deeply incised mountain-side stream. The eastern half of the moor lies on state forest land, the western half is private property. The moor is characterized by a largely undisturbed zonation with a narrow spruce moor edge forest, a mountain pine spruce belt and an open Bult-Schlenken complex.

A drainage system in the form of 9 ditches running west-east over a width of around 125 m was created in the area of the state land: 20 - 350 m long, each 25 m apart. They all led to the east into a main drainage ditch running north and south.

As a result, the open raised bog areas decreased by approx. 1 ha. In 1956 this area still covered 1.4 ha, in 2006 it was only 0.33 ha.

Comparison of the unstocked raised bog area in 1956 (shaded red) compared to today (yellow) (Elisabeth Pleyl 2008)

Documentation of the condition before renaturation

View across the open part of the raised bog from the western property boundary to the east before restoration

Refurbishment planning

In 2008, the Bad Tölz forestry company commissioned Ms. Elisabeth Pleyl from the Centre for Environment and Culture in Benediktbeuern to draw up a hydrological report and a plan for the restoration of around 5 hectares of moorland as the basis for the water law permit procedure and the restoration work.

After recording the ditches and the drainage behavior as well as a height levelling on site, the location of 74 dams within the ditch system was determined with the aim of retaining the water in the moor and permanently raising the water level in the moor (+/-10 cm below the ground surface). 44 dams were planned as timber dams due to the expected higher water pollution. The remaining dams were planned as simple peat dams. The design of the dams was determined in the terrain according to height and length using stakes. The distribution of the dams in the terrain is shown in the following plan. The blue arrows show the direction of flow of the moor water:

Execution:

In January 2009, the work was carried out by the Bad Tölz forestry company following approval under water law.

The moor was opened up for access to the construction site by creating a main track at the southern edge of the moor as well as smaller tracks along the ditches. This resulted in around 800 cubic meters of spruce wood, of which around 150 cubic meters were required for the construction of the weirs.

The dams were installed by a local excavator company commissioned by the forestry company.

Species that benefit from the measure:

Rewetting preserves the habitat for many rare plant and animal species, such as the adder and several butterfly and dragonfly species that are dependent on the raised bog habitat. The bell heather also grows there, presumably due to human intervention, as it is a characteristic species of the Atlantic moors.

Text: Klaus Huschik, Nature Conservation Officer for Southern Bavaria, Bavarian State Forests

As this photo from September 25, 2012 shows, the preservation and expansion of the open raised bog core appears to be assured: