Category Archives: Techniques & methodology

Restoring Sydney’s underwater forests: Crayweed transplant success

Ezequiel M. Marzinelli, Alexandra H. Campbell, Adriana Vergés, Melinda A. Coleman and Peter D. Steinberg

Key words: Seaweeds, coastal biodiversity, kelp ecosystems, Phyllospora comosa, Crayweed

Introduction: Seaweeds are major habitat-forming organisms that support diverse communities and underpin ecosystem functions and services along temperate coastlines globally. Key species of seaweeds are, however, declining and while conservation in a preventative sense is a partial solution to the challenge of habitat degradation, the status of many of the world’s ecosystems clearly demonstrates that conservation, alone, is not sufficient. Crayweed (Phyllospora comosa) is a large habitat-forming seaweed that forms extensive underwater forests on shallow rocky reefs throughout south-eastern Australia, supporting unique diversity and economically important species such as crayfish (Sagmariasus, Jasus) and abalone (Haliotis). However, Crayweed went locally extinct from around 70 km of Sydney’s coastline in the 1980s, coincident with peaks in heavy sewage discharges; and, despite subsequent significant improvements in water quality, it has not reestablished naturally (Coleman et al. 2008).

The overall aim of this ongoing project is to restore Crayweed forests to the Sydney metropolitan coastline. In this case study, our specific aims were to determine (i) whether this species supports different biodiversity than other similar extant habitat-forming seaweeds – thus providing a rationale for restoration – and (ii) whether restoring this species and its associated biodiversity would be feasible; that is, could we achieve levels of survival, recruitment and diversity similar to those in reference locations where this species still occurs.

Works undertaken:

Surveys. We compared biodiversity (densities of abalone, communities of fish and epifauna) associated with crayweed and two major habitat-forming seaweeds in NSW, the kelp Ecklonia radiata and the fucoid Sargassum vestitum, and barren habitats.

Transplanting. We transplanted Crayweed from extant populations north and south of Sydney into three Sydney reefs where Crayweed was once abundant, creating 1 – 4 replicate patches ranging from 5 – 20 m2 in each site, with densities of 15-20 per m2, which are within the range of patch-sizes and densities in natural populations (Fig 1).

Figure 1. A 20m2 Crayweed restoration patch being set up by divers.

Figure 1. A 20m2 Crayweed restoration patch being set up by divers.

Results to date: The surveys of extant Crayweed found that it supported much higher numbers of abalone and different communities of associated epifauna than other similar, extant habitat-forming seaweed species or barren habitats (Marzinelli et al. 2014; Marzinelli et al. 2016).

The Crayweed we transplanted onto Sydney’s reefs generally survived (40-70%), grew (c. 60 cm, total length) and reproduced (5-12 recruits per 0.1 m2 after 1 year) (Fig 2) similarly to those in reference populations (Campbell et al. 2014). In some restored locations, these populations are apparently self-sustaining, with first generation progeny found over 200 m away from the initial transplanted patches.

Figure 2. Recruits growing next to the restoration patch (6 months after transplantation).

Figure 2. Recruits growing next to the restoration patch (6 months after transplantation).

Because the ultimate goal is not only to restore Crayweed but also the biodiversity it supports, we quantified several components of associated biodiversity in replicate ‘restored’, reference and control (non-restored) locations several times before and after the restoration efforts. Initial results on some of these components (e.g. epifauna) suggest that restoring associated biodiversity can indeed be achieved by restoring Crayweed, but to successfully restore all associated species is likely to be a complex and long-term process (Marzinelli et al. 2016).

Lessons learned and future directions: Critical to success are (i) the significant improvement in water quality along the Sydney coastline in recent years, (ii) understanding the ecology and biology of this species, which has male and female adult plants that reproduce synchronously once stressed through the process of outplanting (osmotic stress and drying), and (iii) on a more practical level, minimizing the period between collection and outplanting, which should be done in the same day. In one of the sites, herbivory on the outplanted Crayweed limited restoration success, so we are now identifying the species responsible to guide site selection in future larger-scale restoration efforts.

Stakeholders and Funding bodies. This project is being carried out by researchers at the Sydney Institute of Marine Science & the Centre for Marine Bio-Innovation, University of New South Wales (EMM, AHC, AV, PDS), and NSW Fisheries (Department of Primary Industries; MAC). It is supported by the NSW Recreational Fishing Trust (DPI), the NSW Environmental Trust (OEH) and the Sea Life Trust.

Contact: Dr Ezequiel M. Marzinelli, Senior Research Fellow, Sydney Institute of Marine Science & Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Tel: +61(0)2 93858723; Email: e.marzinelli@unsw.edu.au

Saltmarsh translocation and construction, Penrhyn Estuary, Port Botany, NSW

Mia Dalby-Ball and Andre Olson

From June 2008 to June 2011, ecological restoration work was conducted by Port Authority of NSW in association with the expansion of the port at Port Botany, Sydney, NSW. The purpose was to expand and rehabilitate Penrhyn Estuary.

The saltmarsh works at Penrhyn Estuary involved 2.4 hectares being densely planted with saltmarsh species. In addition to this 3000m2 of saltmarsh was translocated within Penrhyn Estuary. The key driver for the saltmarsh design and plant selection was the requirement for the project to provide habitat for migratory wading birds.

There were many key aspects to the project. Primary among them was the engagement of an expert to undertake a pre-words evaluation and design the wetland construction. It was also important that planning involved representatives from different disciplines including those who would be doing the on-ground work and those monitoring migratory birds. Another key aspect was that approvals and licenses were identified and obtained early.

Saltmarsh construction. Seed collection (from local sources) and plant growing was carried out more than a year before plants were required. (This is because saltmarsh plants are slow to grow, there is a narrow window of time for seed collection and permits are required to collect seed or pieces.)

Implementation works first involved removal of dune weeds (Bitou-Bush, Chrysanthemum monilifera ssp. rotundifolia) and saltmarsh weeds, in particular Spiny Rush (Juncus acutus) of which large plants were hand removed and or cut and painted with herbicide. Germinating seedlings were irrigated with Saltwater. Monthly inspections undertaken with immediate removal of new plants.

This was followed by excavation of land so that it became inundated by monthly high tides. (Monitoring of tidal inundation was carried out to test that levels were appropriate and areas that had water pooling in excess of five days were filled.)

Soil conditioner (organic rich soil) was spread over the sandy substrate and mixed to 100mm, using cultivation equipment. This was followed by planting of over 250,000 saltmarsh plants including of Beaded Glasswort (Sarcocornia quinqueflora) and Salt Couch (Sporobolus virginicus). All saltmarsh plantings were irrigated with fresh water via a sprinkler system.

Fig 1. Translocating Beaded Glasswort via electric boat. (Photo: Dragonfly Environmental)

Fig 1. Translocating Beaded Glasswort via electric boat. (Photo: Dragonfly Environmental)

Translocation of saltmarsh. A 3000m2 area of Beaded Glasswort and Salt Couch was growing on an area that was to be excavated to become mudflats. This area was cut into ~ 20cm x 20cm blocks with 100mm deep soil and lifted by hand (shovels) and put onto wooden sheets (plywood) and transported to the recipient site. Transportation was chiefly by a small boat with electric motor (Fig 1).

The saltmarsh was translocated to the site where the Spiny Rush had been removed. At the recipient site it was planted into the substrate (Fig 2). Spaces between blocks were filled with soil from the donor site. The entire area was irrigated thoroughly with salt water. Irrigation continued for six months while the transplanted material established.

Monitoring. Monitoring existing saltmarsh and proposed saltmarsh creation sites prior to, during and for 2 years post works. Additional monitoring has been conducted for a further 3 years.

Fig 2. Transplanting clumps of Beaded Glasswort and Salt Couch into areas where Spiny Rush had been removed. (Photo: Dragonfly Environmental)

Fig 2. Transplanting clumps of Beaded Glasswort and Salt Couch into areas where Spiny Rush had been removed. (Photo: Dragonfly Environmental)

Fig 3. Sprinkler irrigation during saltmarsh planting. Fresh water irrigation continued for at least 6 months post-planting. (Photo: Dragonfly Environmental)

Fig 3. Sprinkler irrigation during saltmarsh planting. Fresh water irrigation continued for at least 6 months post-planting. (Photo: Dragonfly Environmental)

Lessons learned. At over 230,000 saltmarsh plantings, to our knowledge this is the largest recorded saltmarsh construction project recorded to date. A number of findings have resulted from the project, particularly our trials to arrive at a suitable growing medium for the plantings. We sought a soil that had free drainage good moisture retention properties and contained available nutrients. Fertiliser tablets alone are insufficient in sandy soils. We trialed a range of soil conditioners, with the most successful having high organic content and did not float. Irrigation is required as tidal inundation is not adequate to keep soil moist for seedlings. We found that irrigation was required for at least 6 months

Acknowledgements: Design and pre-works site evaluation was conducted by Geoff Sainty of Sainty and Associates and BioAnalysis.  Implementation and monitoring of saltmarsh during construction and establishment phase (two years monitoring) was carried out by Dragonfly Environmental.  Cardno (NSW/ACT) has been conducting environmental monitoring post establishment phase.

Contact: Mia Dalby-Ball, Ecological Consultants Australia, 30 Palmgrove Road,  Avalon NSW 2107, Australia (Tel: 0488 481 929; Email: ecologicalca@outlook.com) or Andre Olson, Dragonfly Environmental, 1/33 Avalon Parade, Avalon NSW 2107 Australia (andre@dfe.net.au).

Defining reference communities for ecological restoration of Monjebup North Reserve in Gondwana Link

Justin Jonson

Key words: reconstruction; reference ecosystem; planning; ecosystem assemblage; monitoring

Introduction. Bush Heritage Australia’s (BHA) Monjebup North Reserve is a property that directly contributes to the conservation, restoration and connectivity objectives of Gondwana Link – one of Australia’s leading landscape scale restoration initiatives. Building on a solid history of revegetation projects implemented by collaborators from Greening Australia and individual practioners, the BHA management team initiated and funded a $40K Ecological Restoration Planning Project for 400 hectares of marginal farmland in need of restoration.

The specific aim of the Monjebup North Ecological Restoration Project was to 1) plan and 2) implement a ‘five star’ ecological restoration project as defined by the Gondwana Link Restoration Standards. Overarching goals included the re-establishment of vegetation assemblages consistent with the surrounding mosaic of plant communities, with a specific focus on local fauna and the restoration of habitat conditions to support their populations.

Figure 1: Map showing GPS locations of soil auger sampling locations.

Figure 1: Map showing GPS locations of soil auger sampling locations.

Planning and identification of reference communities for restoration of cleared land. The Monjebup North Ecological Restoration Project began with a third party consultancy contract to develop the Monjebup North Ecological Restoration Plan. This work began with the collection of detailed field data, including 120 soil survey pits collected to define the extent and boundaries between different soil-landform units occurring on the site (Fig.1). In the absence of previously defined and/or published information on local plant communities, an additional vegetation survey and report, The Vegetation of Monjebup North, was developed, which included 36 vegetation survey sites widely distributed across the surrounding vegetation (Fig.2). A total of 10 primary vegetation associations were defined within remnant vegetation on and around the site from this work (Fig.3). Additional soil survey pits were established within these defined plant communities to develop relationships between observed vegetation associations and soil-landform units. Cross referencing this information to the 400 hectare area of cleared land resulted in the delineation of seven core reference communities to guide the restoration project. These restoration communities ranged from Banksia media and Eucalyptus pluricaulis Mallee Scrub associations on spongelitic clay soils, to Eucalyptus occidentalis (Yate) Swamp Woodland associations located in low-lying areas where perched ephemeral swamps exist.

Figure 2: Map showing GPS locations of flora survey sampling sites.

Figure 2: Map showing GPS locations of flora survey sampling sites.

Figure 3: Output map of dominant vegetation associations at Monjebup North Reserve.

Figure 3: Output map of dominant vegetation associations at Monjebup North Reserve.

Figure 4: Mosaic of plant communities replanted at Monjebup North in 2012 using direct seeding and hand planted seedlings. A tractor fitted with GPS unit enables real time seeding passes, as shown on the map.

Figure 4: Mosaic of plant communities replanted at Monjebup North in 2012 using direct seeding and hand planted seedlings. A tractor fitted with GPS unit enables real time seeding passes, as shown on the map.

Figure 5: Mosaic of plant communities replanted at Monjebup North in 2013 using direct seeding and hand planted seedlings. A tractor fitted with GPS unit enables real time seeding passes, as shown on the map.

Figure 5: Mosaic of plant communities replanted at Monjebup North in 2013 using direct seeding and hand planted seedlings. A tractor fitted with GPS unit enables real time seeding passes, as shown on the map.

Seed sourcing. Seed from approximately 119 species were collected on and around the site for the restoration works. Seed collections for some species were collected from a number of geographically separate sub-populations, however these were never located further than 10 kilometers from site. Collections were made from at least 20 individuals for each species, and preference was made in collecting from populations which had 200+ individuals.

The primary on-ground works were initiated across four years from 2012 to 2015, starting with a 100 ha project area in 2012 (Fig.4), and a 140 ha area in the following year (Fig.5), both by Threshold Environmental Pty Ltd. A combination of direct seeding and hand planted seedlings treatments were employed, where seed mixes were developed to achieve the bulk of plant recruitment across each of the soil-land form units, and nursery grown seedlings were planted by hand for species found to be difficult to establish from direct seeding or for which stocking densities were to be more closely controlled. This work involved 13 communities and 148 species.

A number of innovative operational treatments were employed. These included grading 5 kilometers of contour banks and spreading chipped vegetation and seed pods, and 180 in situ burning patches where branch and seed material from fire-responsive serotinous species were piled and burned (Fig.6 before, Fig.7 after). Seedlings for rare, high nectar producing plant species were also planted in 203 discrete ‘node’ configurations. Habitat debris piles made of on-site stone and large branch materials were also constructed at 16 locations across the 2012 project areas.

Fig.6 In situ burning of serotinous branch and seed material

Figure 7: Photo of Dryandra nervosa juvenile plants establishing from one of the in situ burn pile locations. Other species used for this technique included Dryandra cirsioides, Dryandra drummondii, Hakea pandanicarpa, Isopogon buxifolius, and Hakea corymbosa.

Figure 7: Photo of Dryandra nervosa juvenile plants establishing from one of the in situ burn pile locations. Other species used for this technique included Dryandra cirsioides, Dryandra drummondii, Hakea pandanicarpa, Isopogon buxifolius, and Hakea corymbosa.

Monitoring. Monitoring plots were established to evaluate the direct seeded revegetation, as presented in the Project Planting and Monitoring Report 2012-2013. Fauna monitoring has also been undertaken by BHA using pit fall traps, LFA soil records, and bird minute surveys.

Results to date. Monitoring collected from post establishment plots in from the 2012 and 2013 areas (2 years after seeding) showed initial establishment of 2.4 million trees and shrubs from the direct seeding (Fig.8 and Fig.9). Results of faunal monitoring are yet to be reported, but monitoring at the site for vegetation and faunal is ongoing.

Figure 8: Graphic representation of monitoring results from 2012 and 2013 operational programs showing scaled up plant counts across the plant community systems targeted for reconstruction.

Figure 8: Graphic representation of monitoring results from 2012 and 2013 operational programs showing scaled up plant counts across the plant community systems targeted for reconstruction.

Figure 9: Photo showing 3 year old establishment and growth of a Banksia media/Eucalyptus falcata Mallee shrub plant community with granitic soil influence from the 2012 Monjebup North restoration project.

Figure 9: Photo showing 3 year old establishment and growth of a Banksia media/Eucalyptus falcata Mallee shrub plant community with granitic soil influence from the 2012 Monjebup North restoration project.

Lessons learned and future directions. The decision to develop a restoration plan in advance of undertaking any on-ground works was a key component contributing to the success of the project to date. Sufficient lead time for contracted restoration practioners to prepare (>12 months) was also a key contributor to the success of the delivery. Direct collaboration with seed collectors with extensive local knowledge also greatly benefited project inputs and outcomes.

Stakeholders and Funding bodies. Major funding for the project was provided by Southcoast Natural Resource Management Inc., via the Federal Government’s National Landcare Program and the Biodiversity Fund. Of note is also Bush Heritage Australia’s significant investment in the initial purchase of the property, without which the project would not have been possible.

Contact information. Justin Jonson, Managing Director, Threshold Environmental, PO BOX 1124, ALBANY WA 6330 +61 427 190 465; jjonson@thresholdenvironmental.com.au

See also EMR summary Peniup

 Watch video: Justin Jonson 2014 AABR presentation

Subtropical rainforest restoration at the Rous Water Rainforest Reserve, Rocky Creek Dam, 1983 – 2016

Key words: Lowland subtropical rainforest, ecosystem reconstruction, drinking water catchment, continual improvement process.

Introduction. Rous Water is actively engaged in ecosystem reconstruction within the drinking water catchment areas it manages on behalf of the community. The aim of these activities is to improve the functioning of essential natural processes that sustain water quality. The methodology used for rainforest restoration by Rous Water has evolved over time through an ‘adaptive management’ process at Rocky Creek Dam. This adaptive management approach has demonstrated that effective large scale sub-tropical regeneration at Rocky Creek Dam is achieved through complete removal of competing plants. The technique has become known as the Woodford Method and is now being applied at other Rous Water restoration sites.

The Rous Water Rainforest Reserve at Rocky Creek Dam is set in the northern headwaters of the Richmond River catchment, on the southern rim of the Tweed shield volcano. Basalt flows from the volcano have produced nutrient rich Red Ferrosol that supported diverse sub-tropical rainforest ecosystems across the region, until the rainforest was largely cleared for agriculture in the late 19th century. The Rocky Creek Dam site is adjacent to the Big Scrub Flora Reserve, the largest remaining remnant subtropical rainforest in the region. This reserve acts as a reference site for the restoration project (Fig 1).

Figure 1. Detail of the regeneration areas at Rocky Creek Dam, showing the areas treated and the year of the initial works

Figure 1. Detail of the regeneration areas at Rocky Creek Dam, showing the areas treated and the year of the initial works

Clearing of land in the vicinity of Rocky Creek Dam by early settlers commenced in the 1890s, with the cleared lands used for the establishment of dairy farms and a sawmill. In 1949, following acquisition of the site by Rous County Council (now Rous Water) for the construction of a water supply dam, this former farmland had reverted to weedy regrowth characterised by a mosaic of native/exotic grass, Lantana (Lantana camara) and Camphor Laurel (Cinnamomum camphora) which supressed any expansion or recovery of scattered rainforest remnants. Transformation of the site commenced in 1983 when Rous Water became actively engaged in ecosystem recovery by systematically removing weeds that suppressed rainforest regeneration, a practice that continues today.

Rainforest restoration methods. The practices and management tools used in rainforest restoration at the site have been previously described by Woodford (2000) and Sanger et al. (2008). The work method typically involves the systematic poisoning and slashing of weeds to promote recruitment of rainforest plants from the soil seed bank and then to facilitate the growth of suppressed rainforest plants, providing a structural framework for further seed dispersal by wind and, particularly, flying frugivores and thus further colonisation by later phase rainforest trees.

Since 1983, an area of approximately 70 ha has been progressively treated in 1-2 ha blocks using this methodology (refer Fig 1), with progressively diminishing amounts of follow-up treatment needing to be conducted in the treated areas over subsequent years to secure successional progression of the rainforest species.

Use of this method means that, due to recruitment from the seed bank and the use of stags (from dead camphor laurel) as perches for seed dispersing birds, very limited planting has been required on the site. This has preserved the genetic integrity of the Big Scrub in this location.

Results. A total of approximately 70 hectares of weed dominated regrowth has been treated at the Rous Water Rainforest Reserve since commencement in 1983 (Figure 1). This is approximately 35 ha since the report previously published in 2000 and represents approximately 30 % of the Rous Water property at Rocky Creek Dam.

This progressive treatment of compartments of weedy regrowth at Rocky Creek Dam has continued to lead to rapid canopy closure by shorter lived pioneer and early secondary tree species, with a gradual progression to higher proportions of later secondary and primary species with increasing time since treatment. All tree species that are listed as occurring in the reference site are not only now present in the restoration area, but informal observations suggest that most, if not all, are increasing in abundance over time (Figs 2-6)

Figure 2. Treated regrowth at the Rous Water Rainforest Reserve, Rocky Creek Dam After 1 year (foreground)

Figure 2. Typical regeneration of rainforest species 1 year after Lantana removal at the Rous Water Rainforest Reserve, Rocky Creek Dam (foreground).

Figure 3. Same photopoint after 6 years

Figure 3. Typical recovery after 6 years

Figure 4. Same photopoint after 12 years

Figure 4. Typical recovery after 12 years

Figure 5. Same scenario after 20 years

Figure 5. typical recovery after 20 years

Figure 6. After 30 years

Figure 6. Typical recovery after 30 years

The structure of the older treated regrowth areas sites appears to be converging on rainforest conditions, as noted by Kanowski & Catterall (2007). Thackway & Specht (2015) depict how 25 ha of systematically treated compartments that were covered almost entirely with lantana are progressing back towards the original Lowland Subtropical Rainforest’s composition, structure and ecological function (Fig 7). Overall the vegetation status in this area was assessed at between 85% and 90% of its pre-clearing status.

This process is, at its oldest 33 years old and in some locations much younger. So it is clear that the development of the subtropical vegetation still has many decades, possibly centuries, to go, before it approaches the composition, structural and habitat characteristics of a primary forest. Notwithstanding the large areas of natural regrowth that are yet to be worked, it is evident that a large proportion of the assisted regeneration areas progressively worked by Rous over the past 33 years now requires only a low level of ongoing maintenance. This shows that these sites are maturing over time and have largely reached a self-organising state, and in the fullness of time will achieve a high degree of similarity to the reference state.  (A recovery wheel for one subsite is shown in Fig 8)

Fig 7, Thackway fig rocky creek dam1

Figure 7. Assessment of change in indicators of vegetation condition in a 25 ha area. This depicts the degree of recoveery of Lowland Subtropical Rainforest found at Rocky Creek Dam, Big Scrub, NSW against a pre-clearing reference. (Graph reproduced with permission. The method used to generate the graph is described in Thackway, R. and Specht, A., (2015). Synthesising the effects of land use on natural and managed landscapes. Science of the Total Environment. 526:136–152 doi:10.1016/j.scitotenv.2015.04.070. ) Condition indices for transition Phase 4 were derived from prior reports including Sanger et al. 2008 and Woodford 2000. Metadata can be viewed at http://portal.tern.org.au/big-scrub-rocky-queensland-brisbane/16908 .

Lessons learned. Using this method of harnessing the natural resilience processes of the rainforest, we have been able to progress the recovery of an important water catchment area, restoring very high biodiversity conservation values in a landscape where rainforest was, and remains, in serious decline., The ability of the high resilience sites at Rocky Creek Dam to respond to the Woodford Method is clearly demonstrated, but there is ample evidence that application of this and similar resilience-based rainforest restoration methods can harnessed resilience at other sites in the Big Scrub that are at greater distances from remnants.

Figure 8. Distribution of management intensity classes across the Rous Water Rainforest Reserve at Rocky Creek Dam.

Figure 8. Distribution of management intensity classes across the Rous Water Rainforest Reserve at Rocky Creek Dam. (Legend for this map is in Appendix 1)

Current work and future directions. Work continues at the site and management is supportive of-site evaluation to assess the extent to which the treated areas are undergoing successional development using a range of available assessment tools.

To assist future planning, and in order to address the issue of how to best estimate and plan for restoration works and associated costs, Rous Water has adapted the methodology developed on the Tweed-Byron Bush Futures Project, where each restoration site/area was assigned a Management Intensity Class (MIC) based on a generalised assessment of site condition, weed composition and cover and other management requirements. (Fig 8) The MIC describes the frequency of restoration work required to restore the site to a minimal maintenance level and how many years this would take to achieve. The MIC aims to describe the extent of management intervention necessary to restore the site to a minimal maintenance level. For this analysis this equates to the establishment of a self sustaining sub-tropical rainforest buffer zone. Each management intensity class is associated with a particular restoration trajectory/cost per hectare, based on visitation frequency by a standard 3 person team and expressed in terms of number of visits required to control / manage weeds. Appendix 1 below shows details of the MIC classification, showing for each class, relevant site criteria, and the estimated level of bush regeneration resources required to bring each class to a low maintenance level.

Contact: Anthony Acret, Catchment Assets Manager,  Rous Water. Tel: +61 (0) 2 6623 3800, Email: anthony.acret@rouswater.nsw.gov.au

Rocky Creek Dam recovery wheel adjacent to Forest Edge

Appendix 1. Legend for Management intensity classes used in Fig 8. (From Tweed-Byron Bush Futures)

Appendix 1. Legend for Management intensity classes used in Fig 8.

Establishment of an assisted natural regeneration model for Big Scrub sub-tropical rainforest: The Woodford Method

The results of long-term restoration at Rocky Creek Dam, have informed the development of an assisted natural regeneration model for sub-tropical rainforest known as The Woodford Method (named after the pioneering restoration work of Ralph Woodford). This method is now commonly applied across the Big Scrub region, particularly on high resilience sites and is more fully explained in Woodford (2000).

Figure 1. Remove Lantana thickets.

Figure 1. Remove Lantana thickets.

1. Winter (July-August) – refer Figure 1. In a typical area of secondary regrowth dominated by weeds such as Camphor Laurel (Cinnamomum camphora), Privet (Ligustrum sinense) and Lantana (Lantana camara), Lantana is the weed that should be killed first. Winter is the best time to do this as it is dry and it won’t reshoot when on the ground. In extensive areas, this can be done effectively by flattening thickets of Lantana with a tractor, then slashing it repeatedly to create a deep mulch, and pulling the Lantana stumps out to disturb the soil. Removing the Lantana thickets also allows access to tree weeds.

Figure 2. Kill Privet and Camphor Laurel.

Figure 2. Kill Privet and Camphor Laurel.

2. Spring (September-October) – refer Figure 2. Tree weeds such as Camphor and Privet have their biggest growth spurt, so this is a good time to give them a shot of herbicide to kill them. (Leaving the Camphor in place rather than cutting them down means that they act as ‘perch trees’ for birds and bats to land on and spread seeds through their droppings). As the Lantana, Camphor and Privet die, their leaves and branches fall to the ground and form a rich mulch on the forest floor. Light is also able to reach the forest floor, where previously it had only reached the canopy.

Spring storms come and wet the mulch, and fungal mycelium (the feeding filaments of fungi) move through the mulch and break it down, fertilising and leaving bare patches of soil where the mulch layer has totally receded.

Figure 3. Remove annual weeds.

Figure 3. Remove annual weeds.

3. Late spring / early summer (November-January) – refer Figure 3. Where you have bare soil, and there is moisture, light and an appropriate temperature, you will get seed germination. The first things to come up are annual weeds such as ‘Farmers Friends’ or ‘Cobblers Pegs’ (Bidens pilosa); ‘Blue Billy Goat Weed’ (Ageratum houstonianum); and ‘Crofton’ or ‘Mistweed’ (Ageratina spp). Annual weeds are always first to appear. They will germinate on the smell of a storm and a slight increase in temperature. Camphor and privet seedlings often come up at the same time.

When the weeds grow, they form a canopy just like the forest but at a height of one metre. In this way, weeds stop light from reaching the forest floor, inhibiting the growth of rainforest seedlings.

Therefore, it is important to remove these annual weeds and not let them go to seed. Depending on time available they are either pulled or sprayed. The experience at this site has been that the seedbank is strong enough to lose some rainforest seedlings in this initial spraying. If using herbicide, two sprays during this season generally removes all the weeds and their seeds.

Figure 4. Weed around rainforest seedlings.

Figure 4. Weed around rainforest seedlings.

4. Late summer / early autumn (February-March) – refer Figure 4.The seeds of rainforest species tend to germinate after the highest summer temperatures (sometimes up to 38 and 40 degrees) have passed. By late February and early March, daytime temperatures don’t generally go over 30 degrees, but the soil temperature and moisture is at its maximum. These conditions can produce a massive germination of rainforest seeds and those seedlings grow up very rapidly. Hand weeding is usually needed around these rainforest ‘pioneers’.

Figure 5. Enjoy the growing rainforest.

Figure 5. Enjoy the growing rainforest.

5. Early winter (May-June) – refer Figure 5. On a good site, with the best seasonal conditions, many of these rainforest seedlings will have grown to saplings above head height and can create a closed canopy within the same year. This means that less light reaches the forest floor, which reduces the amount of weed regrowth in this area – but there is still enough light for later successional rainforest seedlings to germinate, building the rainforest diversity over time.

Note: The process may be slightly different depending on the type of ‘before restoration’ landscape. Refer to Woodford (2000) for more information.

Contact: Anthony Acret,  Catchment Assets Manager, Rous Water, NSW Australia. Tel+62 2 6623 3800; Email: anthony.acret@rouswater.nsw.gov.au

Case Study: Restoring the Lost Shellfish Reefs of Port Phillip Bay

Simon Branigan

Key words: shellfish reefs, native flat oyster, blue mussel, ecological restoration, marine ecosystem

Background. Globally, shellfish reefs are the most threatened marine habitat on earth.  Research published by The Nature Conservancy documented that that over 85% of shellfish reefs have been lost from coastal areas worldwide, with 99% of shellfish reefs ‘functionally extinct’ in Australian coastal waters, including within Port Phillip Bay (Shellfish Reefs at Risk Report).

This dramatic loss of shellfish reef habitat in Port Phillip Bay had occurred by the mid to late 20th century, caused by over-harvesting through destructive dredge fishing, further compounded by pollution, predation and disease in later years.

In an Australian first, The Nature Conservancy Australia (TNC) are part of a research partnership that are trialling different approaches to restoring Port Phillip Bay’s lost shellfish reefs (video link).

Shellfish reefs are intertidal or subtidal three-dimensional habitats formed by oysters and/or mussels at high densities. Shellfish reefs can vary in appearance depending on the dominant reef-forming species. There are many common attributes of shellfish reefs including:

  • They provide habitat and refuge for other species including sessile and mobile organisms, supporting high levels of species diversity and unique assemblages;
  • They can accrete dead shell material such that the reef grows in size and mass over time;
  • They provide food for other organisms, either when consumed directly or through the species assemblages they support.
Figure 1. Clumping native Flat Oysters at 9ft Bank in Port Phillip Bay

Figure 1. Clumping native Flat Oysters at 9ft Bank in Port Phillip Bay

Figure 2. Remnant Oyster Reef in Georges Bay, St Helens, Tasmania. (Photo: Chris Gillies)

Figure 2. Remnant Oyster Reef in Georges Bay, St Helens, Tasmania. (Photo: Chris Gillies)

Restoring the Lost Shellfish Reefs of Port Phillip Bay. A three-year trial was established in late March 2015 to investigate the following research questions:

  • Can the oysters simply grow on the bottom or do they need a rubble base?
  • Can oysters be deployed at a young age and survive, or is it more beneficial for a grow-out on aquaculture leases to gain a ‘headstart’?
  • At what densities do we need to deploy mature mussels? (i.e. Can they create mussel beds naturally on the sediment or require substrate?)

 Reference ecosystem. Historical information and relictual evidence shows that the shellfish reefs of Port Phillip Bay were subtidal with the dominant species being native flat oyster (Ostrea angasi) and Blue Mussel (Mytilus (edulis) galloprovincialis). Healthy reference sites for such reefs are very limited in Southern Australia. Within Port Phillip Bay the only site found so far is a dispersed clumping reef called 9ft Bank (Fig 1). A remnant shellfish reef also occurs in Georges Bay, off St Helens in Tasmania (Fig 2). Further research is planned for the Tasmanian site to complete a biological assessment to inform long-term restoration targets and reef design at Port Phillip Bay and other future sites in the region.

Locations of the restoration trials: The intent is to conduct restoration trials in three locations within Port Phillip Bay, although currently works are occurring at only two sites: Wilson Spit (Outer Geelong Harbour) and Margarets Reef (Hobsons Bay) (Fig 3). These are both old shellfish reefs that are largely dead and covered by sediment (Fig 4). The depth range is between 6 to 8 metres depth with Wilson Spit being a silty mud bottom and Margarets Reef sand.

Figure 3. Port Phillip Bay Shellfish Reef Restoration sites.

Figure 3. Port Phillip Bay Shellfish Reef Restoration sites.

Figure 4. Relictual evidence of previous oyster reef at Wilson Spit restoration site. (Photo: Paul Hamer).

Figure 4. Relictual evidence of previous oyster reef at Wilson Spit restoration site. (Photo: Paul Hamer).

Works Undertaken. As Port Phillip Bay is both reef substrate- and recruitment-limited a reconstruction approach (involving rebuilding substrates and reintroducing oysters and mussels) is a necessary starting point for the restoration, with the longer term expectation of natural colonisation.

The trial has involved the deployment of a total of 6 tonnes of limestone marl substrate in a patchwork of 1m x 1m plots at both sites. Native flat oysters are being raised at the Victorian Shellfish Hatchery and their larvae settled on recycled scallop shells (called cultch) (Fig 5). The larvae are then left for a 3-6 month period on an aquaculture lease before being deployed onto the substrate base (Fig 6). To date over 20,000 live oysters have been deployed to seed the reefs. In addition, over 6 tonnes of blue mussel have also been deployed at different densities and in 3 x 3m plots (Fig 7).

Figure 5. Cultch spat growing out at the Bates Point Aquaculture Lease. (Photo: Ben Cleveland)

Figure 5. Cultch spat growing out at the Bates Point Aquaculture Lease. (Photo: Ben Cleveland)

Figure 6. Limestone rubble base with cultch spat. (Photo: Paul Hamer)

Figure 6. Limestone rubble base with cultch spat. (Photo: Paul Hamer)

Figure 7. Deployed mussel bed at Margarets Reef. (Photo: Paul Hamer)

Figure 7. Deployed mussel bed at Margarets Reef. (Photo: Paul Hamer)

 Monitoring Methodology. The University of Melbourne are contracted to lead the monitoring in Stage 1 of the restoration trial. Baseline sampling was conducted of the trial pre-deployment (trial layout is shown in Fig 8) and subsequent monitoring to be carried out 6 months and 12 months after deployment. Monitoring includes measuring:

  • Oyster survival per shell on the various substrate treatments
  • Oyster growth on the various substrate treatments
  • Mussel survival (inner cores only) and mussel growth as well as shell cover and predator density
  • Baseline community sampling (pre-deployment) of mobile fish, cryptic fish, mobile invertebrates, benthic biota and benthic substrate.
Figure 8. An example of the oyster reef experimental design at the Margaret Reef site.

Figure 8. An example of the oyster reef experimental design at the Margaret Reef site.

Lessons Learned and Future Directions. Early monitoring results from both sites show that oyster spat survival is greater if deployed on a rubble base than directly to the seabed, with cultch loss high on sand, due to burial. Oysters grew on average five times as fast on rubble than sand over winter. We conclude from this that elevation is important for both the survival and growth of oysters.

For the mussels the highest density treatment had the highest mortality at both sites, suggesting that the low density treatment improves survival and may be the most cost effective approach.

The most abundant predator was the native Eleven-arm Seastar (Coscinasterias calamaria).

We consider that scale is important in helping to minimise early losses and this hypothesis will be tested in the second stage of the trail. Planning is in place to scale-up the trial to 20 x 20m plots in late 2016, with a mixed-species approach, combining mussels and oysters rather than having separate treatments. Elevation through large and small limestone rubble will also be tested, integrated with recycled shells sourced from restaurants and wholesalers.

Stakeholders and Funding. The Restoring the Lost Shellfish Reefs of Port Phillip Bay Project is a key element of The Nature Conservancy Australia’s Great Southern Seascapes Program and delivered in partnership with the Victorian Government (Fisheries Victoria) and Albert Park Yachting and Angling Club. All partners have contributed funding towards the project and continue to fundraise.

Contact. Simon Branigan, Estuaries Conservation Coordinator, The Nature Conservancy Australia, Suite 2.01, The 60L Green Building, 60 Leicester Street, Carlton, VIC 3053, Australia. Tel: 0409087278. Email: simon.branigan@tnc.org

WATCH FIRST VIDEO: Shellfish reef restoration in Port Phillip Bay

WATCH SECOND VIDEO: Trialling shellfish reef restoration techiques for potential application across Australia

Brush pack experiment in restoration: How small changes can avoid leakage of resources and underpin larger scale improvements for restoration and rehabilitation

David Tongway and John Ludwig

Key words: Landscape Function Analysis, biological foci, water harvesting, desertification, erosion

The following experiment illustrates how relatively small changes to redirect water flow can capture water and other biological resources at a restoration site. However the process occurs not only at the micro scale but cumulates to site and landscape scales, making it a primary underpinning principles of a method of site analysis, Landscape Function Analysis (LFA) that has been applied across Australia and other countries to assist land managers counter desertification by redesigning processes that regulate the flow of resources, minimise losses and foster cycling. See http://members.iinet.net.au/~lfa_procedures/

The LFA mindset and methodology involve a purposeful change of focus from listing the biota/ species present or absent at a site, to an examination of the degree to which biophysical processes deal with vital resources with respect to stresses arising from management and climatic events.

Fig 1 before

Fig. 1. Before: bare, crusted, low OC soil, erosion, and high water runoff mainitained by low but persistent, set-stock grazing by sheep and kangaroos.

Fig 2. after treatment

Fig. 2. The restoration treatment was simply to build brush-packs across the contour to trap water, soil and plant litter, slowing overland outflow. This also prevented the grazing down to ~1cm. Grass plants were able to maintain about 10cm of photosynthetic tissue.

Fig 4

Fig 3. After 7 years. Clearly the soil properties have improved the ‘habitat quality’ for the target vegetation.

Fig 5 14 years after

Figure 4. After 14 years, native vegetation re-established.

Fig 3. detail of bushpack after 3 years.

Fig 5. Detail of the brushpack after 3 years showing micro-structures capable of slowing water and accumulating resources.

1. tongway table

ANOTHER KEY OBSERVATION RELEVANT TO RESTORATION AND REHABILITATION

Where resources are not captured or leak out of a system, patchiness will become evident as resources self-organise around foci of accumulation – creating ‘patches’ where resources accumulate and ‘interpatches’ from which they ‘leak’.

The Golden Rule for rehabilitation is: “Restore/replace missing or ineffective processes in the landscape in order to improve the soil habitat quality for desired biota.”

Fig 6. Grassy sward healthy

Fig. 6. A grassy sward patch where the grass plants are close enough together that the water run-off is unable to generate enough energy to redistribute the grassy litter, which is evenly distributed. (The slope is from top to bottom in the image.)

There is also no evidence of sediment transport (not visible in this image). This is because of the tortuous path and short inter-grass distance. It would be possible to derive the critical grass plant spacing for “sward” function in any landscape, taking into account slope, aspect and soil texture.

Fig 7. Grassland in patch-interpatch mode, due to exceeding the critical runoff length for erosion initiation. (Slope is from top to bottom.)

Note that litter and sediment have both been washed off the inter-patch and have been arrested by a down-slope grass patch. Note the orientation of the grassy litter strands.

 

 

 

 

 

 

 

 

 

 

 

 

Habitat restoration at Snowy Adit, Kosciuszko National Park

Habitat restoration at Snowy Adit, Kosciuszko National Park

Key words: revegetation, habitat construction, montane, high altitude,fauna.

Introduction. Island Bend Downstream Spoil Dump, known as ‘Snowy Adit’, is one of approximately 30 former-‘Snowy Scheme’ sites in Kosciuszko National Park (KNP) that have undergone rehabilitation and restoration treatments in the last 10 years. The work is part of a program to remediate environmental risks associated with large volumes of rock dumped following underground blasting of tunnels and the cutting of benches for aqueduct pipelines constructed during the former hydro-electric scheme. At Snowy Adit, up to 950,000m3 of rock spoil was excavated and dumped. The footprint of the site is roughly 11 hectares, about 750m long and 150m wide.

Snowy Adit precinct 2008

Fig 1. Snowy Adit precinct 2008

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Fig 2. Snowy Adit precinct 2015

The site sits at an altitude of 1000m on the northern bank of the Snowy River at the junction with the Gungarlin River. The surrounding landscape is relatively intact, providing a reference ecosystem for the project, and occurs in a transitional zone between montane and sub-alpine vegetation. The dominant overstorey species is Ribbon Gum (Eucalyptus viminalis) with the sporadic occurrence of Candlebark (Eucalyptus rubida). The mid layer is dominated by wattle (Acacia species), and the shrub to ground layer includes Narrow-leaf Bitter Pea (Daviesia mimosoides), Burgan (Kunzea ericoides), Bidgee-widgee (Aceana nove-zelandiae), Carex (Carex appressa) and native grass (Poa helmsii). Within the rehabilitation site prior to works, the dominant species were weeds, aside from several shrubs of Burgan and the occasional Ribbon Gum.

Rehabilitation at Snowy Adit aims to restore a level of ecological function and stability by reducing erosion and re-establishing native vegetation. This gives long term protection to adjoining waterways and reduces the risk of weed invasion and habitat loss to the adjoining national park (Figs 1 and 2).

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Fig 3. Earthworks 2008

 

Integrating with natural regeneration on site

Fig 4. Integrating with existing vegetation on site

Works undertaken. The site was split into three management zones, with zones one and two progressively rehabilitated between 2008 and 2010, and zone 3 retained as an ongoing rock resource and storage area with some buffer planting. The rehabilitation techniques employed at each zone included:

  1. Earthworks to reduce steep embankments, provide track and bench access across the site for revegetation works and provide for future potential water flow across the site with a series of shallow swales and pond depressions (Figs 3 and 4);
  2. Ground disturbance to address highly compacted nature of existing surface;
  3. Removal of waste materials where possible – this included the recycling of 260 tonnes of metal that had been buried/dumped across the site;
  4. Addition of Coarse Woody Debris, primarily in windrows to provide wind shelter and thatch to hold straw and create microclimate. This material was sourced from logs and tree crowns removed during local trail clearing;
  5. Addition of compost production and water crystals to individual planting holes
  6. Planting 110,000 tubestock of 11 species from locally collected seed and cuttings in three stages;
  7. Mulching with rice straw;
  8. Weed control prior to pre works;
  9. Spreading of woodchip in weed prone areas such as access tracks and temporary nursery location.

After high initial browsing on planted seedlings by wallabies, deer and rabbits, most planting areas were progressively fenced. The steel 1.8 metre high fence had rabbit-proof netting to 1.05m high with a 300mm skirt pinned/rocked to ground, and hinge joint wire to 1.8m (Photo 4). Once in place, almost 100 percent plant establishment success was achieved.

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Fig 5. Flowering Acacia influencing nutrient status

Results to date. Soils and soil function. Monitoring has shown that three years after revegetation, soil infiltration, nutrient cycling and leaf litter values are still lower than the reference site, but soil stability measures are currently higher, possibly due to the role of young plants in binding the soil. Litter levels have understandably decreased since the original application of mulch and the amount of exposed rock has increased. It is expected that the growth of the revegetation will produce increasing amounts of litter and reverse this trend.

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Fig 6. Development of planted vegetation 6 years on

Vegetation. BioMetric http://www.environment.nsw.gov.au/papers/BioMetricOpManualV3-1.pdf was used to assess the condition of the vegetation along a 30m transect at 4 years after planting. This showed that the plantings had not yet developed to overstorey height but many of the Ribbon Gum had grown to midstorey height, providing a cover of 7.5%. The ground cover was mostly litter (52%) and rock (52%) with 2% bare ground. Native shrub cover of the ground layer was 20%, grasses 2% and forbs 8%. No exotic species were encountered along the transect so the total of 30% plant cover in the ground layer was all native. The number of woody stems was high (990) and similar to the control site. The level of exotic species incursion to the site was very low.

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Fig 7. High levels of coarse woody debris on site

Fauna. Rehabilitation works have greatly improved the habitat values of Snowy Adit, as evidence by increasing fauna recorded at the site. Pre- and post-treatment surveys have shown that, 5 years after revegetation commenced, the site is now used by at least sixty vertebrate species – 36 birds, 17 mammals, four reptiles and three frogs. Thirty-nine species were not recorded in the original 2006 survey, with 19 species (15 birds, two mammals and two frogs) attributed as a direct result of the rehabilitation works undertaken since 2006. Five threatened species were recorded in the rehabilitation area, with one additional listed species, the Powerful Owl (Ninox strenua), located in immediately adjacent forest. These threatened species were the Eastern Pygmy-possum (Cercartetus nanus), Eastern Bent-winged Bat (Miniopterus orianae oceanensis), Eastern False Pipistrelle (Falsistrellus tasmaniensi ), Gang-gang Cockatoo (Callocephalon fimbriatum ) and Flame Robin (Petroica phoenicea). The first three threatened species were not located in the original 2006 survey. The most outstanding discovery was the location of four Eastern Pygmy-possums within the fenced area of the rehabilitation area. Sixteen bird species now appeared to be either resident or regular visitors within the plantings rather than occasionally ranging into the area from adjacent forest; with nests of five species located. Several species were observed feeding flying dependent young juveniles within the planting area – such as the White-browed Scrubwren (Sericornis frontalis) and Rufous Whistler (Pachycephala rufiventris).

It is considered likely that, over time, some 29 species (23 birds, four reptiles and two mammal species) which were only recorded in adjacent forest and control sites in the current or original surveys will recolonise the area as the plantings continue to grow.

Lessons learned and future directions. The attention to detail in site preparation to create soil surface roughness and niches and microclimates in denuded and exposed sites at Snowy Adit is likely to explain the level of success achieved to date in terms of vegetation and habitat development. Constantly revisiting the site has also played an important role as it allowed measures to be taken to address overgrazing by both native and pest species. Taking the time to plan the works but also having flexibility to adapt and seek opportunities reaped benefits. A fortuitous supply of unwanted coarse woody debris and woodchip stockpiled at a nearby work depot also assisted with the establishment and growth of plants, controlled weeds and accelerated the return of native fauna using the for site as habitat.

Stakeholders and Funding bodies. The Rehabilitation of Former Snowy Scheme Sites Program was established from Snowy Hydro Limited funding and is managed by the Landforms and Rehabilitation Team in National Parks and Wildlife Service, NSW. Nicki Taws (Greening Australia Capital Region, Project Manager) conducted the vegetation monitoring. Martin Schulz conducted the fauna surveying and reporting.

Contact. Gabriel Wilks, Environmental Officer, National Parks & Wildlife Service NSW, PO Box 471 Tumut 2729, phone 062 69477070, Gabriel.wilks@environment.nsw.gov.au; Elizabeth MacPhee, Rehabilitation Officer, National Parks & Wildlife Service NSW, PO Box 471 Tumut 2729, Tel: +61 2 69477076, Email: Elizabeth.macphee@environment.nsw.gov.au.

Also read full EMR feature:Rehabilitation of former Snowy Scheme sites in Kosciusko National Park

Watch video short presentation by Liz MacPhee

Watch video short description of planting techniques Liz MacPhee

Watch video rediscovery of Smoky Mouse on rehab site Gabriel Wilks

EMR summary Restoration of Bourke’s Spoil Dump #2: https://site.emrprojectsummaries.org/2013/08/22/bourkes-gorge-spoil-dump-2-restoration-kosciuszko-national-park-2/

EMR summary Jindabyne Valve House Restoration: https://site.emrprojectsummaries.org/2013/08/20/jindabyne-valve-house-kosciuszko-national-park-nsw-2/

EMR summary Yarrangobilly Seed and Straw Production Area: https://site.emrprojectsummaries.org/2013/08/17/yarrangobilly-native-seed-and-straw-farm/

Snowy Adit project recovery wheel (National Standards for the Practice of Ecological Restoration in Australia)>

ATTRIBUTE CATEGORY RECOVERY LEVEL (1-5) EVIDENCE FOR RECOVERY LEVEL (derived from transect data)
ATTRIBUTE 1. Absence of threats
Over-utilization

 

5 Site is no longer utilized and is dedicated to conservation.
Invasive species

 

5 Very low potential for invasion
Pollution

 

5 Nil sources of pollution
ATTRIBUTE 2. Physical conditions
Substrate physical

 

5 Site still very rocky but within range of natural variation compared to reference.  Likely self-organizing.
Substrate chemical 5 Similar to reference.
Water chemo-physical

 

5 soil infiltration, nutrient cycling and leaf litter values still lower than reference, but soil stability higher. Likely self-organizing.
ATTRIBUTE 3. Species composition
Desirable plants

 

5 Greater than 60% of local indigenous trees, shrubs, grasses and forbs establishing. Likely self-organizing.
Desirable animals

 

5 Prior bare site now has > 60 vertebrate species (36 bird, 17 mammal, 4 reptile and 3 frog. (5 Threatened.)
No undesirable species

 

4.5 Very low weed status.
ATTRIBUTE 4. Community structure
All vegetation strata

 

5 Trees at midstorey height (7.5% cover) shrub (20% cov) grasses (2% cov) and forbs (8% cov)
All trophic levels

 

5 Trophic structure evident with very high faunal recolonization including Powerful Owl nearby
Spatial mosaic

 

5 Similar to reference.  Likely self-organizing.
ATTRIBUTE 5. Ecosystem function
Productivity, cycling etc

 

5 High levels of litter (52%) and evidence of decomposition. Likely self-organizing.
Habitat & plant-animal interactions 5 High levels of woody debris, nesting by birds and mammals. Flowering and fruiting evidence of pollination
Resilience, recruitment etc 4.5 Likely seed banks building and some recruitment of shrubs and herbs. Trees old enough for resprouting.
ATTRIBUTE 6. External exchanges
Landscape flows

 

5 Site now fully integrated into extensive, high quality natural area
Gene flows

 

5 Likely restored
Habitat links

 

4.5 Likely restored although fencing yet to be removed

 

 

Stewartdale Nature Refuge koala habitat restoration in South Ripley, south east Queensland

Key Words: reconstruction, assisted regeneration, planning, koalas, conservation

Introduction: The Stewartdale Nature Refuge is located in South Ripley, south east Queensland on private land owned by the Sporting Shooters Association of Australia (SSAA). The 969 ha block contains live shooting ranges, large open areas dominated by pasture grasses, a substantial lagoon frequented by many bird species and extensive natural areas. The area being restored is 211 ha of dry sclerophyll vegetation, containing a number of Regional Ecosystems (REs) being restored through large scale planting (reconstruction) and assisted regeneration approaches. Its conservation value is heightened by the fact that it connects to the Karawatha Flinders Corridor, the largest remaining stretch of open eucalypt forest in south-east Queensland.

Condition ranges from large degraded areas (i.e. pasture) to native vegetation that contains both regrowth and remnant dry sclerophyll. All areas were impacted by varying levels of weed infestation due to previous clearing and ongoing disturbance from cattle grazing. Natural disturbances such as regular fire and periodic floods have also contributed to disturbance at the site. More than 30 weed species impact the project area at varying levels and the species and impacts vary with the condition of the land. Open areas were dominated by pasture grass such as Setaria (Setaria sphacelata) and Rhodes grass (Chloris gayana) in addition to fast growing annuals, although infestations of Leucaena (Leucaena leucocephala), Prickly Pear (Opuntia stricta) and large clumping Bamboo (Bambusa sp.) also required significant control efforts. In more forested areas (and underneath isolated remnant trees) weed species included Lantana (Lantana camara), Creeping Lantana (Lantana montevidensis), Corky Passionfruit (Passiflora suberosa), Easter Cassia (Senna pendula var. glabrata), Siratro (Macroptilium atropurpureum) and exotic grasses, annuals and groundcovers.

The aim of the project is to restore, native plant communities present within the Stewartdale project site to support local koala populations. Our goals are to:

  • Repair native vegetation including the structure, integrity and diversity to support koala populations
  • Strengthen the resilience and regenerative capacity of native vegetation
  • Restore and expand native regrowth vegetation by controlling weeds
  • Maintain the project site so weeds do not negatively impact the development and recovery of native vegetation
  • Protect drainage lines, gullies and slopes from erosion
  • Protect and enhance the water quality of Bundamba Lagoon
  • Construct fauna friendly fencing across the site with the aim of protecting planted trees from herbivory
  • Reduce the risk of fire moving through the site and impacting restoration works by conducting strategic slashing activities to reduce fuel loads.

Planning. A restoration plan was developed after detailed site assessments and negotiations with the landholder, land manager and state government were finalised integrating Nature Refuge conditions and current land use and future management requirements. The site was divided into zones and sub-zones to assist directing works including applying a range of restoration approaches – i.e. assisted regeneration and reconstruction (‘revegetation’) and several planting models and species mosaics to different parts of the site. Detailed maps were produced for each zone and included information such as the location of all tracks, fences, assisted regeneration zones, wildlife corridors, planting areas according to each RE and numbers of species and plants to be installed per zone. The plan also included detailed information on restoration approaches; weed control at all stages of the project; seed collection and propagation; site preparation including the specifications and location of all fencing, tracks, rip lines and areas of concern (i.e. identified hazards across the site); how to carry out all works in each zone; site maintenance requirements for 5-7 years; and monitoring requirements.

PP2b after site preparation.JPG

Fig 2. Preparation for planting  at Stewartdale Nature Refuge.

PP2b after planting Mar 2016

Fig 2. After planting to support local Koala population, Mar 2016.

Works to date. Site preparation commenced with the collection of seed from on and around the wider property and surrounds ensuring that all species to be planted were collected from a minimum of 10 widely spaced parent trees. Primary weed control started with the control of weeds in the 65 ha of assisted regeneration zones and the control of other woody weeds across reconstruction areas in preparation for slashing and other activities. More than 18 km of fauna friendly fencing (i.e. no barbed wire) was installed to protect planted stock from browsing by large herds of macropods and cows. Two large corridors were retained for fauna to reach Bundamba lagoon from different parts of the regional corridor as it is an important resource for many local and migratory fauna. Slashing across open areas was commenced and followed by the installation of rip lines to alleviate soil compaction and assist efficient planting activities. Weeds and pasture grasses were then sprayed out along all rip lines. 114 000 koala food and shelter trees were planted according to the RE for each section and according to the local conditions (i.e. whether it was low lying, on a ridge or near infrastructure). Some additional frost resistant and local Acacia species were also added to particularly frost prone areas to assist the development of a canopy and the protection of developing vegetation.

The 114 000 tubestock were installed over a 7 week period with the last stems being planted in April 2015. All trees were fertilised and watered at the time of planting and where possible, slashed grass spread across the rip lines to assist retaining moisture and slowing weed regrowth. (Follow-up watering was applied to all planted stock between September and October 2015) Nearly 2000 (1 m high) tree mesh guards were installed to protect planted stock in fauna corridors.

Series shot 1.1

Careful spot spraying to reduce weed while protecting natives

Series Shot 1.2

Growth of saplings is improved without competition.

Results to date. As of March 2016, weeds have been significantly reduced across the 65 ha of assisted regeneration areas. Unfortunately a wildfire fire went through approx. a third of the project area after primary and follow up weed control works had been completed. Fortunately the event was prior to planting though the fire did reduce the number of trees regenerating in assisted regeneration patches as many were too young to withstand the fire. New germinations are however occurring and the level of native grasses, groundcovers and other native species have increased due to ongoing weed control efforts.

Despite heavy frosts in winter 2015, a flood event in May 2015 (150 mm of rain fell in 1.5 hours) and now an extended dry period, the planting is developing well with the average height of trees at over a metre tall and mortality under 5%. Weed control is continuing across the project site with efforts currently concentrating on the control of many annual weeds such as Cobbler’s Peg (Bidens pilosa), Balloon Cotton (Gomphocarpus physocarpus) and Stinking Roger (Tagetes minuta) and many exotic grasses such as Setaria (Setaria sphacelata) and Rhodes grass (Chloris gayana) to reduce competition to planted stock. Assisted regeneration areas are being joined up to planting zones wherever possible to further assist the development of the site.

It should also be noted that Birds Australia have recorded 69 bird species on site.

Ongoing works: Regular maintenance continues on the site with the control of weeds particularly along rip lines where weed germination and growth is rapid. Slashing is also regularly done between the rip lines and along tracks and fence lines to assist access around the site and the management of fuel loads and therefore wildfire across the site. It is expected that the time it takes to complete each maintenance rotation will begin to reduce as plants become more established and start to develop a canopy.

Weed control will also continue in all assisted regeneration zones and is also expected to reduce with the development of native vegetation structure and diversity together with the reduction of the weed seed bank. Ongoing slashing, fence maintenance and monitoring will continue for another 3-5 years though the exact time period will be determined by the State government.

Monitoring including soil moisture readings, transects to assist determining survival rates across the site and photographic monitoring is regular and further supports 6 monthly reporting requirements.

Stakeholders and funding bodies: Department of Environment, Heritage and Protection, Queensland State Government; Sporting Shooters Association of Australia (SSAA). Photos: Ecosure.

Contact Information: Jen Ford (Principal Restoration Ecologist, Ecosure TEl: +61 (0)7  3606 1038.

 

Restoration at Numinbah Conservation Area, City of the Gold Coast, Queensland

Key Words: assisted regeneration, restoration planning, conservation

Introduction: Numinbah Conservation Area, located in the hinterland of the Gold Coast in south-east Queensland, is one of many natural areas managed by City of Gold Coast’s Natural Areas Management Unit (NAMU). The 598 ha property contains 12 Regional Ecosystems (REs) ranging from sub-tropical and dry rainforest to dry and wet sclerophyll types; and include riparian zones, steep areas, gullies and rocky outcrops. Its conservation value is heightened by the fact that it connects to other reserves including the World Heritage areas of Springbrook.

Condition ranges from large degraded areas (i.e. pasture) to native vegetation that contains both regrowth and remnant areas. All areas were impacted by weeds due to previous disturbance from logging and subsequent cattle grazing. More than 35 weed species impact the site at varying levels with the most notable species across the site being Lantana (Lantana camara). Edges are impacted by exotic vines such as Glycine (Neonotonia wightii), the understorey by many herbaceous weeds such as Mistflower (Ageratina riparia) and rainforest zones by persistent weeds such as Coral Berry (Rivina humilis) and Passion Vines (Passiflora spp.) to name a few. Approximately 60 hectares of open area are dominated by pasture grasses and other weeds.

The aim of the project is to restore, to the extent possible, the structure, function, dynamics and integrity of the pre-existing vegetation and the sustaining habitat that is provided. Our goals are to:

  • Improve the health of vegetation and habitat types across the site
  • Improve connectivity for flora and fauna
  • Reduce fuel levels in fire prone ecosystems and the risk of hot fires sweeping through the site and wider landscape
  • Increase the resilience of the site
  • Improve water quality
  • Increase the health, populations and distribution of threatened species – flora and fauna
  • Reduce the need for weed control maintenance over time i.e. to a level of minimal maintenance
  • Provide nature based recreational opportunities and environmental education along this section of the Gold Coast Hinterland Great Walk

Planning. An ecological restoration plan was developed after detailed site assessments and the site was divided into precincts, zones and sub-zones to assist directing works. Information in the plan included species lists, weed control information, maps and detail on how to restore each area and progressively link zones. A detailed fire management plan was also developed for the site that took into account wildfire mitigation, restoration zones, the location of threatened species, site objectives, REs including their recommended fire regimes, and the capacity of areas to regenerate.

Works to date. Works over the last 9 years have covered more than 190 ha. The main approach to restoration has been via assisted regeneration consisting mainly of large scale weed control and the fencing of areas to reduce the impact of cattle. Further works have involved planting a section of creek to assist stability and connectivity across a section of the site; and the propagation and translocation of four threatened flora species (details not disclosed for security reasons).

Where low intensity fuel reduction burns were conducted in dry sclerophyll vegetation, timely follow up weed control was applied to ensure re-shooting Lantana, Molasses Grass (Melinis minutiflora) and other weeds did not fill gaps and to support the colonisation and growth of native vegetation. In remnant and regrowth vegetation, systematic weed control using a range of techniques has been applied. E.g. large areas of Lantana were controlled using three techniques: cut, scrape and paint where it was in close proximity to native plants; over-spraying after isolating infestations; and, spot-spraying when it germinated or was re-shooting. Weed species were continually suppressed to ensure native species germinated and grew to a point where most gaps have been filled with native vegetation. As each area developed and maintenance reduced, efforts were put into continually expanding the work fronts.

A propagation and translocation project was also implemented in partnership with Seqwater. More than 1150 individuals (four species) have been propagated, planted into their particular niche and have been monitored and reported on annually. This will continue until all species are considered to be self-sustaining i.e. flowering, fruiting and reproducing.

(a)NCA8n_20080502

(b)NCA8n_20080827

(c) NCA8n_20090716

(d)NCA8n_20100625

(e)NCA8n_20110630

(f)NCA8n_20151130

Figure 1, (a-f) represents an annual sequence of recovery after control of Lantana and subsequent weed at one photopoint from 2008 to 2011, with the last photo taken in 2015. The results reflect accurate and timely weed control to support the recovery of native vegetation. (Photos: City of Gold Coast)

Results to date. As of July 2015, weeds have been significantly reduced across the 190 ha treated area to a point where maintenance is being applied, with some areas requiring little to no maintenance. In a number of areas this reduction of weed has also significantly reduced fuel levels.

Increased abundance and diversity of native vegetation has occurred across a range of ecosystem and habitat types within the reserve. Open areas once dominated by dense Lantana have taken approx. 3 years to naturally regenerate with a range of pioneer, early secondary and later stage rainforest species (Figs 1-3). Many of those areas now include continuing recovery of later stage species and contain a large diversity of seedlings, groundcovers and ferns. More diverse communities have recovered with a large range of species (depending on the ecosystem / ecotone) and support a diversity of fauna species. Works in four of the larger precincts have now joined up and weed control works are continuing to expand all regenerating areas.

More than 7000 plants installed along the open riparian stretch are establishing with native species regenerating amongst the planting. After approx. 7 years the average height of the planted canopy is approx. 5-7m tall.

Ongoing works: All current work zones are being continuously extended ensuring progress made is maintained. The open area (e.g. paddock) is being reduced over time as vegetation is encouraged to expand (i.e. by continuing to control weeds to past the drip lines of all native vegetation). Fences that currently contain cattle (i.e. to assist managing open areas for access, fire management and to ensure funds are spent in more resilient areas) are being moved to continue to reduce the size of highly degraded areas. Fire management, large scale weed control and the monitoring and evaluation of threatened species, together with fauna surveys, is continuing.

Stakeholders and funding bodies: Natural Areas Management Unit (NAMU), City of Gold Coast and Seqwater. Contact Information Paul Cockbain, Team Leader Restorations +61 7 5581 1510