Restoration Ecology

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Restoration Ecology

• Sustainable Ecosystems
• Week 12
• 28/10/2009

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Definition of Management Options

• Restoration
• Re-establishment of the communities that were
  present before disturbance. There is consensus
  that this is the most desirable option for land
  managers.
• Rehabilitation
• Reconstruction of habitat.
• Revegetation
• To re-create vegetation cover.

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Restoration

• Restoration is a complex task, requiring the
  restoration of ecological processes, vegetation
  and soil structure, as well as populations of
  animal populations.
• Efforts should benefit the environment by
  improving the quality of the land, habitat,
  biodiversity, landscape amenity and reduce
  salinity.
• Restoration efforts may not be able to match the
  pre-disturbed species composition, but they can
  restore many of ecosystem functions and recover
  many component of the original biodiversity.

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How is restoration best achieved?

• Through the comparison of neighbouring remnant
  ecosystems.
• Remnant remaining intact piece.
• Historical records (inc. traditional ecological
  knowledge TEK) if available.

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Ecosystem communities to be considered in
re-establishment inc.

• Vascular plants
• Biological Soil Crust (BSC)
• Invertebrates
• Higher order fauna i.e. Large mammals and lizards
• Soil microbes and fungi (in particular
  Mycorrhizae)
• Also,
• Soil physical and chemical properties inc. soil
  type, grain size, organic carbon content, pH,
  salinity and levels of macro and micro nutrients
• Note Ecosystem - An environmental unit
  consisting of living and non-living components
  that interact with an interchange of nutrients
  and energy

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Role of Vascular Plants in Restoration Efforts

• Pivotal role in energy capture and carbon
  storage, nutrient and water cycling, landscape
  stability, and in providing habitat for native
  species.
• Roots bind the soil, thereby reducing wind
  generated surface erosion.
• Return a large amount of percolating water to the
  atmosphere through transpiration thus reducing
  water erosion, rising water tables and salinity.
• Canopy cover not only provides shelter but
  reduces the visual scars in a degraded landscape

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Role of BSC in Restoration Efforts

• BSC is a mix of lichens, mosses, liverworts,
  blue-green algae, green algae, fungi and other
  organisms found in upper layer of soil.
• BSC is very slow growing, slow to re-establish
  and easily disturbed which can result in
  desertification of arid lands.
• BSC often remains biologically inactive in arid
  environments due to lack of water, activity only
  commencing when water is made available through
  precipitation or condensation.

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BSC continued...

• BSC is ecologically important.
• BCS component species are essential colonisers of
  bare soils.
• It is strongly related to soil stability due to
  particle binding properties and is a vital
  component in arid ecosystems for the prevention
  of wind and water erosion, a primary goal of
  restoration.

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BSC continued...

• BSC provides a source of food and shelter for
  terrestrial invertebrates.
• Finally, BSC also influences the infiltration of
  water into the soil, the decomposition of
  organisms and the fertility of soil, thus
  improving the soil as a medium for plant growth.

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Role of Invertebrates in Restoration Efforts

• Invertebrates, particularly ants, are excellent
  bio-indicators of ecosystem stress and
  disturbance. This ability is due to a number of
  attributes of invertebrates and their role in the
  ecosystem.
• BIO-INDICATOR - a species used as a proxy for
  measuring aspects of an ecosystem.
• Ants often harvest seeds resulting in their
  dispersal and thus alter abundance and
  distribution of plants.

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Invertebrates continued...

• Invertebrates are the greatest contributors to
  species richness in any ecosystem (excluding
  microbes)
• They are important for ecosystem function,
  playing a key role in nutrient cycling, plant
  growth and reproduction and the establishment of
  the food chain.
• They also pollinate plants, break down organic
  matter and nutrients and are an important food
  source for other fauna.

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Role of Mycorrhizae in Restoration Efforts

• Should be considered in restoration management
  practices to obtain truly diverse ecosystems.
• A mycorrhiza is a symbiotic, non-pathogenic,
  permanent association between a plant root and a
  specialized fungus.
• Mycorrhizal fungi may improve the uptake of both
  macro and micro nutrients from the soil.
• Contributing to plant nutrition and growth.

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Mycorrhizae continued...

• This symbiosis between plant and fungus allows
  each to survive in environments of low
  fertility, periodic drought, diseases, extreme
  temperatures and other natural stresses.
• Evidence to suggest the Mycorrhizal fungi play a
  key role in determining the composition of the
  plant community.
• Thus are a vital part of biodiversity and
  therefore a key measurable indicator of recovery
  of degraded ecosystems in response to restoration
  efforts.

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Role of Soil physical and chemical properties in
Restoration Efforts

• Of particular concern are levels of available
  nitrogen, potassium and phosphorus.
• Nitrogen is essential for photosynthesis, growth
  and reproduction, but, high levels can increase
  weed germination.
• Potassium regulates the opening and closing of
  plant stomata and is used in photosynthesis and
  disease resistance.
• Phosphorus is essential for photosynthesis,
  nitrogen fixation, growth and root development.
• Attempts to restore such nutrient deficient
  ecosystems are less likely to succeed.

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Soil physical and chemical properties continued...

• Changes in hydrology are also a concern.
• Large areas of Australia are at risk of dry-land
  salinity.
• The clearing of deep rooted native trees reduces
  the uptake of water from the soil, increasing the
  amount of water feeding to the water table,
  mobilising salts stored deep within the profile,
  causing wide spread salinisation.

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Indices used to quantify ecosystem communities

• Density the number of individuals per unit area
• Abundance the number of individuals in a given
  area
• Percentage Cover (plants only) the percentage
  area occupied by a species
• Frequency the probability of species occurring
  in a sample
• Species Richness number of species in a
  community
• Species Diversity the combination of the number
  of species and their abundance in a community
  indicating variety of life-forms.
• Percentage of Exotics proportion of introduced
  species

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Restoration Techniques

• Direct seeding - spreading and germination of
  seed in-situ. Has potential to work over large
  areas with relatively low costs.
• Tudestocking - seed germinated and raised in
  containers and then transplanted into site to be
  restored. Expensive and time consuming but can
  have higher success rate.
• seed used should be all local provenance, i.e.
  Collected as close as possible to site to
  maintain genetic integrity and accommodate for
  reproductive viability and local adaption.

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Restoration Techniques continued...

• Also, weed control is standard practice prior to
  direct seeding or tubestocking to decrease
  interactions or competition between sown species
  and non-sown residual species.
• Weed species can dominate, suppress and exclude
  native plant species changing site conditions.
• However, weed species may have some value as
  habitat for some fauna.

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Restoration Techniques continued...

• Once habitat has been re-established higher order
  fauna can be re-introduce either by natural
  succession, perhaps enhanced by the creation of
  bush corridors, or translocation of species.
• Pest species need to be considered and controlled
  for a successful outcome. These ferals include
  rabbits, foxes, cats, even invertebrates such as
  Spanish Snails.

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Case Study 1 Mine-Dump Restoration

• Personal research into the Comparison of seven
  year old topsoiling and seeding treatments for
  arid zone terraced mine-dump restoration, Iron
  Baron, Whyalla, South Australia.
• Mining has a variety of known impacts on the
  natural environment, including wildlife and
  habitat loss. Mined landscapes are susceptible to
  erosion contaminating ecosystems both on the
  mine-dump and off-site.
• Mining industry is becoming increasing aware of
  the importance of restoring exploited mine-dumps
  to a natural state, either through environmental
  and social conscience or enforced by legislation
  and leasing agreements.

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Location of Study Site
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Iron Baron Treatment Site
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Mine-Dump Restoration Continued...

• Thesis compares different mine-dump restoration
  techniques including terracing, topsoiling and
  seeding.
• Topsoiling involves the top layer of soil
  (containing the seed bank) gathered off-site
  before operations and respread in its original
  location after closure of operations.
• reserve of viable seed present within the soil
  and its surface.
• Seeding involves the spreading of locally
  obtained seed onto the surface that is to be
  restored.

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Plot Layout Methodology
20 treatment plots covering area of 5000m2 10m
wide bulldozed terraces separated by 5
m Terraces collect and retain surface
water Treatments include Topsoil Seed, Topsoil
No Seed, No Topsoil Seed, No Topsoil No Seed
(Terraced Only). Each replicated five
times. Compared to 5 neighbouring remnant sites.
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Mine-Dump Restoration Continued...

• The aim of the project was to determine which
  treatment was most successful at restoring the
  site most similar to that of neighbouring remnant
  ecosystems.
• The thesis concluded that for the Iron Baron
  mine-dump terracing alone (using neither topsoil
  nor seed) is sufficient for revegetating the site
  to similar density, percentage cover, species
  richness, species diversity and percentage of
  exotics.

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Revegetation Graphs
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Revegetation Graphs
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Revegetation Graphs
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Revegetation Graphs
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Revegetation Graphs
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Revegetation Graphs
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Mine-Dump Restoration Continued...

• Topsoiling achieved the best results when
  considering macro-invertebrate abundance, species
  richness and species diversity, indicating that
  topsoiling may be advantageous in restoring other
  aspects of the ecosystem.
• None of the tested treatments were successful at
  restoring any aspect of BSC communities.
  Reflection of the slow growth of component lichen
  and moss species.

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Case Study 2 Restoration of Degraded
Agricultural Land

• Personal research in progress into direct seed
  mix and tubestocking treatments for restoration
  of degraded agricultural land, Pt. Wakefield,
  SA.
• Crop cultivation and livestock grazing has
  altered many Australian Ecosystems.
• Effects include soil degradation, changes to
  hydrology and simplification and homogenisation
  of the ecosystem.

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Restoration of Degraded Agricultural Land
continued...

• The thesis is to compare the relative success of
  two treatments (diversity of direct seed mix and
  the use of tubestock to restore dominant
  community types).
• The analysis of the direct seed mix and tubestock
  treatments included the assessment of vascular
  plant species, invertebrate species, native plant
  species with roots infected with mycorrhizal
  fungi and both physical and chemical properties.

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Restoration of Degraded Agricultural Land
continued...

• It has been demonstrated that planting locally
  native species in agricultural areas
  significantly improves biodiversity when compared
  to that of existing cleared paddocks.
• There is also evidence that degraded soils can be
  improved through the planting of carefully
  selected plant species.

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Back FROM THE BRINK

• Peter Andrews Australian Story documentary