prof. dr. gerhard wiegleb btu cottbus, germany restoration … · btu cottbus, germany restoration...
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Prof. Dr. Gerhard Wiegleb
BTU Cottbus, Germany
Restoration of heavily disturbed
landscapes – the lignite post mining
landscape around Cottbus
Vilm, July 2012
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Contents
Principles of ecological restoration
• Goal functions and reference states, aim conflicts, types of
landscapes to be restored
Case study: Open cast lignite mining landscape in Lower Lusatia,
East Germany
• Legal and economic framework
• Own research results
Conclusions
• General principles of restoration, the human factor, the role of
scientists, necessity for information exchange
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Principles of ecological restoration
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Definition of Ecological Restoration
• Ecological Restoration is an attempt to guide damaged ecosystems to a previous, healthier, more natural, or any other desired condition (adapted from SER Primer on Ecological Restoration*).
• The prefix “Re-“ does not necessarily imply a historic state.
• “Attempt“ indicates that restoration can fail because of many uncertainties in the restoration process.
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* http://www.ser.org/content/ecological_restoration_primer.asp
Examples of ecological restoration
Ecosystems are embedded in landscapes: mosaics of two or more ecosystems that exchange organisms, energy, water and nutrients (on a large-scale)
• Rehabilitation of river courses and flood plains
• Restoration of soil degradation caused by desertification, salinization etc.
• Reclamation of degradation and devastation caused by mining
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http://www.cpre.org.uk/what-we-do/energy-and-waste/quarrying-
and-mining/the-issues
http://rainbowfish.angfaqld.org.au/Habit
at.htm
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0
“Landscaping”
Regional planning
EIA/SEA Directive
Landscape and urban planning
Agricultural and forest
planning
Precautionary
approach
Protective
Approach
Restorative
approach Ecological restoration
Instruments
Habitats Directive
Conservation law
- Species protection
- Habitat protection
- Protected areas
Indicators
- Macrophytes
- EU birds
- Area size
- etc.
Sustainable use
Conservation
Strategies
Environmental Liability Directive
Habitats Directive
“EIA”
Red = EU legislation
Ecological restoration (textbook approach)
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Renaturalization (incl.
“extensification”)
Restoration (“restitution”,
“sanitation“, “regeneration”)
Rehabilitation
(“revitalization“)
Self-sustaining
rehabilitation
Reclamation
(“remediation“)
Reconstruction
Reintroduction
What else? Creation?
Species composition
Biomass/nutrient
content
No action
natural
Increasing
ecological
integrity?
Source: modified from A.D.Bradshaw, www.beloit.edu
Ecological restoration (refined approach)
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Biotic integrity (species, habitats)
Abiotic integrity
(functions, processes)
Original state
(natural or
cultural)
Disturbed state
Ecological trajectory: Developmental pathway of an ecosystem e.g.
from an unrestored to a desired state of recovery
Ecological restoration - a dynamic model
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Time
Desired ecological functions
Ecosystem of natural
or cultural landscape
More or less
degraded system
Damage,
degradation
Restoration
Further
degradation
Unsuccessful
restoration
Threshold for success
Ecological restoration in Europe
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Type Ecosystem type Aim
Restoration of
natural landscapes
Rivers, lakes, bogs
and fens, salt
marshes, forests
Reduction or
minimization of
land-use
Restoration of
cultural landscapes
Wet grassland,
heathland, arid
grassland,
hedgerows, also
some forest types
Continuation or
reintroduction of
historic land-use or
its simulation
Restoration of
heavily disturbed
landscapes
Mining areas,
military areas,
quarries, urban and
industrial waste
land
Obvious damage
has to be repaired.
Desired states are
being initialized or
reconstructed
Aim conflicts within ecological restoration
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• Examples: natural beech forest vs. urban areas
Close-to-naturalness Biodiversity
Some natural habitats in Central Europe originally
have been less diverse than anthropogenically
disturbed ones
Conflict
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Biodiversity and Naturalness
Species no.
Taxon
In Central
Europe
In beech
forests
In cities
Mammals
98
27
22
Birds
400
70
200
Reptils
14
5
4
Amphibia
19
7
10
Snails and
slugs
490
70
55
Spiders
2,280
560
680
Crayfish
900
26
8
Myriapods
200
60
25
Beetles
6,800
1,500
1,190
Butterflies /
moths
3,000
1,300
1,880
Hymen-
opterans
10,000
700
1,110
Dipterans
6,000
1,080
240
Other insects
3,000
580
800
The assumed price of
biodiversity gain?!
The sustainability triangle
14
Economic
dimension Social
dimension
Ecological
dimension
Willingness-to-pay
Reference
states
Ecosystem
services
Human
population
Restoration is often falsely regarded as a technical process only. However,
the human dimension has to be taken into account as well.
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Naturalness and Wildness
Naturalness can be decomposed into two concepts:
• Wildness – freedom from human control and
manipulation (actualistic)
• Naturalness s. str. – native species, patterns, and
processes (historic)
Source: http://leopold.wilderness.net
Restoration of lignite post mining
landscapes in Lower Lusatia
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Brandenburg University of Technology Cottbus (BTU)
Map of Germany
Medium mountains
Alps
Glacial lowland
Luckau
Berlin
Germany
Cottbus
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Overview of the landscape
Military training area
Lignite mine After Pilarski
Distribution of mining areas
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• 800 km2 devastated
• 2500 km affected by
lowering of ground
water
• 18 mines closed
down (yellow)
• 5 mines active
(brownish)
• 2 mines to be
extended and 3
mines to be opend
up (red)
History of lignite mining in Lusatia
• Mining started around 1789, below ground mining in the 19th century.
• Since 1900 open cast mining was favoured, both for economic reasons and
for avoiding casualties. Shafts often collapsed because of the loose sandy
substrate.
• In 1924 the first conveyor belt bridge was introduced in the mine site
Plessa (55 km southwest of Cottbus). Conveyor belt bridges were combined
with shovel excavators since 1934, later also with bucket-wheel excavators.
• First attempts for restoration were made around 1930 (afforestation with
Scots Pine).
• Since 1960 mining was intensified because of the energy shortage in East
Germany. Since 1973 60-m conveyor belt bridges were used.
• A legal obligation for reclamation existed but could not follow the excavation.
After 1989 and the closing down of many mines the German state became
the owner of many unreclaimed mines and had to carry the financial burden
of reclamation.
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Mining technology and obvious damage
21 http://www.lausitzer-braunkohle.de/feld_welzow_1.php
Active mines Cottbus-Nord
(above) and Nochten (below)
Damage in the adjacent areas because
of groundwater lowering
http://de.wikipedia.org/w/index.php?title=Datei:Tagebau_Nochten,_K
W_Boxberg.jpg&filetimestamp=20080920182845
The environmental impact of open cast mining
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The main impacts are
- Destruction of land (= devastation) including fauna
and flora
- Lowering of groundwater level up to 100 m, creating
completely new hydrological conditions
- Creatings dangers in former of landslides or
solifluction of lose sediments
- Changing the mesoclimate of the region (already the
dryest region in Germany)
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Seeding of grasses for erosion
control
Starting conditions
Afforestations with Red Oak
Standard reclamation measures
Natural succession in terrestrial habitats (from open
land to forest)
P. Denkinger
25
http://www.schlabendorfer-
felder.de/sammeln/lokale_akteure/vegetation/vegetation_einfuehr
ung.htm
From dryland to wetland
Upwelling ground water after wet summers since 2009
Process of Ecological Restoration
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Restoration Goal possible, sustainable, local needs, reasonable cost
Restoration Objectives Ecosystem attributes, priorities
Measurable Success Criteria What criteria over what time scale?
Topsoil Retained (e.g. strip mining):
• Clearing Existing Vegatation • Topsoil Handling • Earthworks
Re-vegetation
Nutrient accumulation and cycling
Indigenous volunteer species
Topsoil Lost/Buried (e.g. tailings dams)
• Assessment of Wastes/Sites • Site Preparation
Adaptive Management Replanting, fire/pest management
Monitoring
Assessment of Success Criteria
Measurement, feedback to proceding stage
Aims of mining restoration
Reclamation aims according to German mining legislation are simple and
legally binding.
• Restoration of the previous state with respect to landuse, usually
forestry and agriculture
• Danger prevention, in particular prevention of land slides and
solifluction of the lose sediments, avoiding disturbance by wind erosion
• Reintegration of the mining areas into the regional water household,
with respect to water quality and ground water level
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Comparison of restoration of different ecosystem types
River Peat land Mining area
Legal obligations Direct, EU Water
Framework
Directive
Indirect, EU
Habitats and
Birds Directive
Direct, national
mining law
Economic need Obvious because
of damage to
cities and cultural
goods
Remote, benefit
of ecosystem
services not
quantified
Unclear on the
long term
Goals Clearly defined to
be specified on a
case-based basis
Simple: peat
depths, water
level, no
eutrophication
Set by mining law
but in contrast to
nature
conservation law
Instruments Multiple, from EIA
to EU programs
Multiple, mostly
from agricultural
planning
Classical
reclamation
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Own research
29
Habitat types
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Analysis of change
based on remote
sensing data Antwi 2007
M. Pilarski U. Nocker
1995 2000
Total Land Area 5598,81 5619,91
Number of patches 4938,00 10472,00
Mean Patch Size 1,13 0,54
Edge Density 308,76 451,82
Mean Shape Index 1,38 1,31
Shannon Diversity Index 1,79 2,18
Shannon Eveness Index 0,75 0,81
Development of landscape
heterogeneity 1995 and 2000
31 Landscape is getting more heterogenous
Antwi 2007
Landscape characteristics - time lag effects
32
Shannon Diversity Index
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
1888 1991 1995 1998 2000 2003
Year
Nu
mb
er
Nord (SDI) Süd (SDI)
Peak 18 years after closing
Still increasing 15
years after closing
despite all
reclamation effort!
Antwi 2007
Chronosequence of Plant Species In Open Areas
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Chronosequence of Arthropod Species No.
34
age (years)
Invertebrate animals come very fast as well
Ln S
Capture of diaspores
Diaspores come very fast
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Highly acidic?
Possible obstacles?
Production limitation due to sediment inhomogeneity
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pH > 4 pH > 4 pH < 4 pH < 4
Planted Scots Pines do not grow (filter effect of low pH):
good or bad depends on the viewpoint
Acid mining lakes
38 pH = 2.0, leading to die back of trees after upwelling of acid groundwater
Sooner or later later the free sulfuric acid appears in the surface waters
Avifauna of mining lakes
39
Habitat type Site characterisation Bird species
Large rest-holes Deep water, steep slopes, sparse aquatic and riparian vegetation, mostly acidic, pH 2.1–4.5, rarely neutral
Black-headed Gull (Larus ridibundus) Mediterranean Gull (Larus melanocephalus)
Herring Gull (Larus argentatus) Eastern Yellow-legged Gull (Larus cachinnans)
Western Yellow-legged Gull (Larus michahellis) Common Gull (Larus canus) Common Tern (Sterna hirundo)
Small water
bodies
Shallow water, partly temporary, with aquatic vegetation and reed belts, mostly neutral, pH 5-7
Marsh Harrier (Circus aeruginosus) Great Reed Warbler (Acrocephalus arundinaceus)
European Crane (Grus grus)
Streams Often only temporary, partly filled with iron-rich, acidic mining water
No specialized avifauna
From Blaschke et al. 2000
Characteristics of mining water
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Mining waters are
- Acid
- Turbid
- Iron-rich
Before they are released into the surface water system, they
must be purified by artifical wetlands (= former rest lakes
which are used as natural sewage plants)
- Turbidity and iron can be removed by sedimentation
- Acidity can be removed by neutralization with limestone or
organic waste (!)
- But not for „ecological reasons“ (see the „defense of the
plume moth“, J. Dahl)
Outlook and conclusions
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Types of restoration projects
• Top-down activities, government induced, run by experts only (the bog landscape project, at least in the beginning)
• Top-down approach including participation of various groups such as local administration, people, NGOs, private sector etc. (the ordinary post mining case)
• Model projects proposed by scientists
• Bottom-up activities triggered by the local community (mostly small-scale, but see following example)
42
A positive example: “Kolonisten gesucht“ (“Colonists
wanted“)
43 http://www.schlabendorfer-
felder.de/auswerten/download/subicon_steckbriefe_2010_ebook.pdf
Landscape workshop Schlabendorfer Felder
• Knowledge transfer between science and practice
• Embedding biodiversity discourses into discourses about regional development
• Environmental education by ecological research
• By exhibitions
Wiegleb - Anders - Rißmann
www.schlabendorfer-felder.de
Transparenz, Systematik,
Dokumentation
Sammeln: Werkstattausstellung Auswerten: Workshops und
Pleinaire Verknüpfen:
Abschlussausstellung 19.6.10
… and publications
Nature conservation: fixed guiding principles vs. „look,
what is possible“
Natural dynamics vs. management to keep areas open
Natural dynamics is related to social dynamics
Ecologists must accept a new role: from expert judgment to service and
partnership
Wiegleb - Anders - Rißmann
Critical dialogue between
scientists and practitioneers
Forestry: New forest images, new chances
• Flexibility is also required from
all landusers
• Foresters in Central Europe are
used to strict separation of
forest and open areas since
1850
• The new situations allows
succession forest which grow
without interference by
foresters.
Wiegleb - Anders - Rißmann
Conclusion from the mining example
• Still, after 20 years restoration aims remain controversial.
• The focus on restoring agriculture areas and forests is unbroken. It
took a long time until the local population recognized the potential
of their new landscapes. The process of decision making is now
more relaxed (see Landscape Workshop, www.schlabendorfer-
felder.de )
• Around 25 % of the reclaimed land is now reserved for nature
conservation (Natura 2000 areas according to EU Habitats
Directive, Specially Protected Aareas according to EU Birds
Directive, protected areas according to national legislation)
• Rethinking was triggered by external actors with a lot of money,
who bought “waste land“ and started to implement nature
conservation projects (Heinz Sielmann Foundation, NABU)
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Personal statements
48
The role of scientists in restoration
• We must consider the fundamental roles of actors, stakeholders, public vs. experts, half-experts, laymen etc.
Scientists may take different roles in the restoration process:
• As advisors (experts on the political level)
• As party involved (in regional model projects, as participant in discussion on restoration aims)
• As scientists only (carrying out research on an interesting object)
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Summary
• Restoration may be driven by many motives, e.g.
legal, cultural, ethical, and economic ones.
• Still, there would be no restoration without non-
scientific motives, but the will be no successful
restoration without scientific knowledge
• Our credo is that good ecological science will
eventually lead to good ecological restoration.
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Thank you for your attention!
• I thank Dr. U. Bröring (Cottbus), P. Denkinger (Hamburg), Dr. M. Pilarski
(Potsdam), Dr. K. Anders (Müncheberg), Dr. E. Antwi (Tokyo) and Dr. T.
Peschel (Berlin) for valuable contributions to the work.
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