Restoring upland swamps of
Southern Mount Lofty Ranges of
Project profile for the
Society for Ecological Restoration International and Global Restoration
Network
Friends of
1. SUMMARY AND INTRODUCTION
This profile summarises a large remnant-scale ecological
restoration project in the
The project area contains headwater and riparian wetlands that
have been substantially changed through human use and conversion for water
exploitation, livestock grazing, and agriculture. Past removal of native
vegetation, substrate disturbance, and watercourse degradation have resulted in
altered vegetation communities and dense environmental weed invasion. Prior to
restoration work focal sites contained degraded communities with only very
simplified assemblages of indigenous species.
Weed species formed over 80% of vegetation cover, resulting in
displacement of native plant species, depletion of native seed banks and
impairment of regeneration processes. Without active intervention there was no likelihood
of autogenic ecosystem recovery.
Restoration of the tributaries and headwater swamps of
1.1 Conservation Imperative
Around 75% of swamp habitats in the southern
2. GEOGRAPHIC LOCATION
The project is located within the
3. STAKEHOLDERS & BUDGET
The project is a partnership between Friends of Scott Creek
Conservation Park, the Threatened Plant Action Group (TPAG), private
landholders and the Department for Environment and Heritage. Grant funding has
been received from DEH, SA Water, Urban Forests and Biodiversity Program, and
the
4. ECOSYSTEM & IMPACTS
4.1 Previous ecosystems
The few remaining examples in the district suggest that typical
headwater swamp ecosystems consisted of a varying mosaic of plant associations
including tea-tree and wattle shrublands over ferns, sedges, rushes and herbs.
Swamp wattle (Acacia provincialis), Silky tea-tree (Leptospermum
lanigerum), Prickly tea-tree (L. continentale),
Red-fruit cutting-grass (Gahnia sieberiana), Tall sedge (Carex appressa), Square twigrush (Baumea
tetragona), Soft water-fern (Blechnum minus), Hop goodenia (Goodenia ovata), and
4.2 Impacts
Past removal of native vegetation, substrate disturbance, and
watercourse degradation have resulted in altered vegetation communities and
dense environmental weed invasion. Past ecosystem impacts include clearance of
native vegetation, livestock grazing, soil cultivation, fertilisation and
compaction, manipulation of surface water flow and creek channels. Both
non-indigenous plant and animal species (Blackberry,
species,
reduction of native seed banks and impairment of regeneration processes.
4.3 Causes and duration
Prior to 1970 most of the creeklines and swamps in the project
area formed part of small privately owned bush blocks which had been partially
cleared or modified for subsistence horticulture from the early to mid 1900’s.
Following park gazettal the area was abandoned in the early 1970’s. Unchecked
invasion by woody weeds followed and dense Blackberry (Rubus fruticosus aggregate)
stands developed along creek lines in the project area, excluding and
suppressing most indigenous species. Prior to commencing restoration work (c.
1997) almost all of these areas were severely degraded by dense Blackberry,
5. RESTORATION GOALS AND PLANNING
The broad aim of the project is to return targeted ecosystems
(insofar as possible) to pre-1836 composition and species richness and to
improve vegetation structure and condition from virtual weed monocultures (i.e.
Blackberry thickets) to their presumed structurally diverse and species rich
state.
Our goals for ecosystem restoration are to:
• increase native plant abundance
(cover, density);
• increase native species
diversity;
• stabilise and/or augment
threatened plant populations;
• reduce weed biomass
over time as wetlands recover;
• increase the area of
available habitat for indigenous species.
• demonstrate a practical
restoration model for broader application
6. PROJECT IMPLEMENTATION
The general technical strategy for restoring degraded native
vegetation communities is to:
• define priority areas to be
restored;
• assess sites and determine the
presence of indigenous species;
• undertake brush-cutting to
establish access into Blackberry thickets;
• cut and swab shrub weed species,
stem inject tree weed species;
• allow blackberry to regrow and
spray regrowth;
• assess and protect regenerating
indigenous plant species;
• propagate non-regenerating
indigenous species and establish in bare areas to assist recovery of indigenous
vegetation;
• frequently follow-up weed
regrowth by hand pulling and by spot spraying;
• expand intensively managed areas
once recovered and where implementation resources permit; and
• patrol and maintain all
previously worked areas through ongoing weed control.
Implementation standards have been achieved by careful
consideration of the following ecological and management factors.
Selectivity
The adopted weed control methods have reduced herbicide use and
off-target damage and maximised selectivity. Approaching work this way has
allowed a closer examination of regenerating areas. We have tried keeping
disturbance to native vegetation, soils, water, and substrates to a minimum.
Careful hand weeding has reduced disturbance and prevented opening up too much
ground too quickly, an important factor as weed species often establish much
faster on disturbed ground than most natives.
Seasonality & timing
Seasonal factors and plant growth have been considered in
scheduling management tasks. Blackberry spraying has been done in optimum
conditions and not just by a monthly calendar. As conditions
vary each year weeds have been observed and treated during active growth
periods, when under the least stress. Cut and swabbing or stem injection
is more flexible but has been avoided when weeds are heat/water stressed or
during dormant phases.
Regenerative capacity
The regenerative capacity of native vegetation and residual seed
banks has been utilised instead of mass planting to guide natural regeneration.
We have been surprised by the longevity of native seed banks in some areas
where Blackberry has long dominated. We have found it much more important to
wait and observe what regenerates before revegetating with extrinsic material.
Where after time it is obvious that few natives are regenerating or weeds
appear the only germinating plants, augmenting with locally sourced tube-stock
is carried out. With species like Tea-trees seed can be hand broadcast to effectively
increase regeneration. Herbivory by rabbits, deer and kangaroos has also taken
a heavy toll in some regenerating areas.
Gradual, staged implementation
All work implemented over the past twelve years has been in
gradual stages with the rate of natural regeneration utilised to guide the
intensity of required management intervention and expansion of work into new
areas. Invaded areas have opened up slowly as rapid removal of established
habitat will impact on those species which have adapted to it. This is
especially the case with several bird species. We are very conscious of this
and only work on 50-100 meters in one area at any one time. We only continue further
when that section has regenerated to a state where it is providing comparable
vegetation cover to the prior infestation. Harnessing the regenerative capacity
of managed sites has helped build their ecological resilience and aided their
recovery.
Translocations (augmentation plantings) are being considered for
small threatened plant populations. Several small swamp herbs and sedges have
been slashed around to maintain required successional habitats and patch
diversity. A nomination has been prepared for the Directory of Wetlands of
National Importance as part of the project (Jury et al. 2006). Project leaders are
experienced practitioners with advanced botanical and on-ground management
skills. Project volunteers have been well trained in restoration and management
techniques. Careful pre-work surveys and detailed botanical reconnaissance has
been undertaken through regular visits to all sites. Unknown species have been
retained until positive identification by expert field botanists. Only experienced,
specialist contactors with stipulated work briefs have been utilised. Ongoing
monitoring and
7. PROGRESS TO DATE
Restoration work has been implemented for approximately 25
hectares of wetland and 100 hectares of adjoining dry woodlands, open forests
and heaths. Removal of Blackberry thickets and other dense invasion by
environmental weeds (
7.1 Specific project sites
Almanda Creek
A permanent spring-fed creek containing Manna gum over
Silky tea-tree and swamp wattle shrubland, sedges, ferns and rushes. Almanda Creek contains permanent pools inaccessible to non-native
trout and is therefore an important refuge for a local population of Mountain
Galaxias (Galaxias olidus). The state threatened Sickle greenhood (Pterostylis falcata) and
Blue-star (Pratia pedunculata) creeper inhabit creek banks and Lewin’s Rail (SA Vulnerable) was
first sighted here in 2006 (2 adults & 1 young). Blackberry has been
retained along an adjoining roadside to limit recreational impacts.
Mackereth Creek/Fox Bog
A perched fern bog between two waterfalls above small gorges and a
broader creek swamp. Staged removal of Blackberry cover has resulted in
discovery of two new regional plant species records for the southern
Bush Rat Creek
Blackberries previously covered all but the oldest tea-trees
creating a dense, shading thicket unsuitable for indigenous species. The Mount
Lofty Ranges Speedwell was disappearing under blackberry however careful
removal through cutting and swabbing around surviving individuals has resulted
in vigorous shoot production, seeding and the recruitment of several new
seedlings. The SA Threatened Small bent-grass (Deyeuxia minor) and rare Swamp
raspwort (Haloragis brownii), not previously recorded in the park, also appeared following
blackberry removal. Most of the Leptospermum
lanigerum stands were senescing without
recruitment and reasonably intact native vegetation occurred close to the
creekline.
Viminaria Creek
Long dormant seed of Golden spray (Viminaria juncea)
germinated within months of blackberry removal. This species had previously
died out in this creekline as well as Swamp raspwort (Haloragis brownii) which
has also since recolonised along with a suite of shrubs, ferns, sedges and rare
grasses. Only a few senescing Leptospermum
lanigerum and Blechnum minus remained
but the creekline now has stands along its whole length.
Picture 1: Upper Viminaria Creek 1 year after
Picture 2: Upper Viminaria Creek following assisted regeneration,
2009
7.2 Interest in the project
Whilst there has been some interest from government agencies and
other community groups, there is little evidence that our approach is catching
on. Limiting the adoption of our restoration approach at a broader scale are:
• Lack of required botanical
recognition skills and experience working with ecological processes (such as
succession);
• Lack of awareness of weed
invasion threats to biodiversity or at least preparedness to tackle the problem
appropriately;
• Lack of patience and persistence
in gradually implementing restoration work;
• Unwillingness to commit to the
physical work required to restore degraded ecosystems.
• The challenging and
long-term temporal scale of restoration and lack of support to progress such work.
• Human tendencies to merely
intellectualise problems rather than shouldering direct personal responsibility
in addressing them.
• A preoccupation by
government and academia with conservation science, policy and planning at the expense
of on-ground implementation and tangible outcomes.
7.3 Monitoring and research links
Annual monitoring of vegetation structure and species composition is
being undertaken to evaluate the effects of management. Photo-points and
transects (point-line intercept & interval plots) have been established to
monitor changes in vegetation structure and composition. Ongoing population
counts are undertaken for threatened plant species. Updated site species lists
have been compiled by expert field botanists on an ongoing basis. Permanent
vegetation monitoring quadrats using NCSSA Bushland Condition Monitoring
methodology are planned for 2009. Bird Banding has been undertaken near some sites.
7.4 Lessons learned
Our work has demonstrated that a high level of natural
regeneration is still possible on wetland sites after assisted regeneration
treatments, despite the sites having been so degraded that few native species were
evident. Site restoration has been achieved mainly through staged
implementation of selective weed removal. Three methods of Blackberry control
have been adopted.
1. Buffer creation - cut and swabbing of Blackberry to create a
managed ‘buffer’ zone around rare or threatened species or where indigenous
species are well established, before using other methods to expand weeded
areas.
2. Slashing in better sections - Thickets of dense Blackberry are
slashed to just above ground level in winter, allowed to regenerate until
summer then sprayed. This has proven effective for smaller areas and/or where
higher native biomass or species richness is present, as regeneration of
natives is easier to observe from the beginning. Spot spraying of Blackberry
regrowth can then be carried out several times over the following summer.
3. Large dense infestations - Larger, mass infestations have been
sprayed and left for a year. This method leaves dead canes as habitat for some
time before they break down to enable control of regrowth. It can take longer
for native species regeneration but end results are similar. Only 50-100 metres
are done in this way at any one time.
No magic bullets or quick fixes have been found for restoring
these ecosystems. The importance of regular follow-up spot spraying in the
first few years (at least twice per season) is critical in reducing future weed
control demands. After this time most germinating blackberry is from seed and
easily hand
Picture 3: Upper Bushrat Creek following Blackberry slashing, June
2005
Picture 4: Upper Bushrat Creek following assisted regeneration,
November 2006
Picture 5: Upper Bushrat Creek following assisted regeneration,
March 2007
Picture 6: Upper Bushrat Creek following assisted regeneration,
March 2009
8. FURTHER
Bates R (2005) Rare and localised plants in three
sister fern-bogs of Scott Creek CP. Bandicoot
Tails. 97 April-May 2005, Newsletter of the Friends of
Harding CL (2005) Wetland
Inventory for the Fleurieu
Jury T & T Hands (2005) Restoring plant diversity in upland
swamps of the
Australasian Plant Conservation. Vol 13,
Jury T, T Hands, R Bates & D Reid (2006) Nomination of
Littlely, T. (1998). A
Biological Survey of the Fleurieu Peninsula Swamps. Report prepared for the Nature Conservation
Society of South Australia,
Smith K, A Prescott, C Carter & T Berkinshaw (2003) Native Vegetation Management: A needs analysis of regional service
delivery in
SA Water (2000) The State of
Weblink to Friends of
9. CONTACT INFORMATION
For information about this project, contact:
Mr Tom Hands
President, Friends of
Phone: (08) 8388 2150
Email: almanda@bigpond.com.au
ACKNOWLEDGEMENTS
Compiled by Tom Hands and Tim Jury, March 2009 with
input from Tein McDonald. Thanks
to all who
have
participated in or supported the project, particularly members of the Friends
of Scott Creek
Watton and Jenny Dawes.
Citation
Hands T & T Jury (2009) Restoring
upland swamps of
Project profile for the Society for Ecological
Restoration International and Global Restoration Network.
Friends of
