Category Archives: Techniques & methodology

Integrating conservation management and sheep grazing at Barrabool, NSW

Martin Driver

Key words: semi-arid, grazing management, conservation management, rehabilitation, ecological restoration

Introduction. Barrabool is a 5000 ha dryland all-Merino sheep property between Conargo and Carrathool in the Western Riverina, NSW. Native pastures are the mainstay of Barrabool, as they are of other grazing properties in the arid and semi-arid rangelands of New South Wales that generally lie to the west of the 500 mm average rainfall limit.

Indigenous ecosystems at Barrabool occur as native grassland, mixed acacia and callitris woodlands and shrublands. The main grass species in the grasslands are Curly Windmill (Enteropogon sp.), White Top (Rytidosperma sp.), Box Grass (Paspalidium sp.), Speargrass (Austrostipa spp.), and Windmill Grass (Chloris sp.). Broad-leaved species include Thorny Saltbush (Rhagodia sp.), Cotton Bush (Maireana sp.) and a diverse annual forb layer in Spring..

The majority of the property has belonged to the Driver family for over 100 years. Like many of the surrounding stations a gradual but noticeable increase in exotic species occurred during the mid-to-late 20th Century, and a decline in native species. This transition has occurred because of species being transferred by livestock movements and because sheep graze not only on grass, but also saltbush shrubs and sub-shrubs as well as seedlings of native trees such as Boree (Acacia pendula) and White Cypress Pine (Callitris glaucophylla). It is well known, for example, that the preferential and continuous grazing of Boree by sheep can turn a Boree woodland into a grassland .within a manager’s lifetime unless rest and regeneration are allowed.

In recent decades – because of the Driver family’s interest in conservation and our exposure to advances in grazing management, paddock subdivision and stock water relocation – we have developed in recent decades a managed grazing system based on feed availability, regeneration capability and seasonal response to rainfall. It was our hope that this system could improve the condition of native vegetation while also improving feed availability.

Figure 1. Boree (Acacia pendula) and Thorny Saltbush (Rhagodia spinescens) in grazed paddocks at the Driver’s 5000 ha sheep property, Barabool, in the western Riverina. (Photo M. Driver).

Figure 1. Boree (Acacia pendula) and Thorny Saltbush (Rhagodia spinescens) in grazed paddocks at the Driver’s 5000 ha sheep property, Barabool, in the western Riverina. (Photo M. Driver).

Works undertaken. Over the last 35 years we have progressively fenced the property so that it is subdivided by soil type and grazing sensitivity, with watering systems reticulated through poly pipe to all those paddocks. This enables us to control grazing to take advantage of where the best feed is and move stock from areas that we are trying to regenerate at any one time; and it gives us a great deal more control than we would have had previously.

Using our grazing system, we can exclude grazing from areas that are responding with regeneration on, say Boree country, for periods of time until Boree are less susceptible to grazing; at which time we bring stock back in. We take a similar approach to the saltbush and grasses, moving sheep in when grazing is suitable and moving them off a paddock to allow the necessary rest periods for regeneration. In this way we operate a type of adaptive grazing management. We also have areas of complete domestic grazing exclusion of very diverse and sensitive vegetation which are essentially now conservation areas.

Figure 2. Mixed White Cypress Pine Woodland grazing exclosure on Barrabool with regeneration of Pine, Needlewood, Sandalwood, Rosewood, Butterbush, Native Jasmine, mixed saltbushes and shrubs. (Photo M. Driver)

Figure 2. Mixed White Cypress Pine Woodland grazing exclosure on Barrabool with regeneration of Pine, Needlewood, Sandalwood, Rosewood, Butterbush, Native Jasmine, mixed saltbushes and shrubs. (Photo M. Driver)

Results. The native vegetation at Barrabool has noticeably improved in quality terms of biodiversity conservation and production outcomes over the last 35 years, although droughts have occurred, and in fact been more frequent during this time.

In terms of conservation goals Boree regeneration and Thorny Saltbush understory restoration has been both the most extensive and effective strategy. Areas of mixed White Cypress Pine woodland have proven to be the most species diverse but also offer the greatest challenges in exotic weed invasion and management. The Pines themselves are also the most reluctant to regenerate and suffer many threats in reaching maturity while many of the secondary tree species are both more opportunistic and show greater resilience to drought and other environmental pressures. The increase in perenniality of grass and shrub components of the property have been significant, with subsequent increase in autumn feed and reduced dependence on external feed supplies.

In terms of production outcomes, after the millennium drought the property experienced three seasons in a row in which there was much less rainfall than the long term average rainfall. At the beginning of that period we had the equivalent of more than the annual rainfall in one night’s fall and then went for 12 months from shearing to shearing with no rain recorded at all. Yet the livestock and the country, however, did very well compared to other properties in the district, which we consider was due to the stronger native vegetation and its ability of the native vegetation to withstand long periods without rain.

Lessons learned and future directions. While many other sheep properties in the wider area are more intent on set stockingin their grazing practices, the results at Barrabool have demonstrated to many people who have visited the property what is possible. I am sure we are also are having some effect on the management systems of other properties in the district especially in the area of conservation areas excluded from grazing.

What we plan for the future is to explore funding options to fence out or split ephemeral creeks and wetlands and encourage Inland River Red Gum and Nitre Goosefoot regeneration.Our long term goal is to maintain the full range of management zones (including restoration zones earmarked for conservation, rehabilitation zones in which we seek to improve and maintain biodiversity values in a grazing context, and fully converted zones around infrastructure where we reduce impacts on the other zones.

Contact:   Martin Driver Barrabool, Conargo, NSW 2710 Email: barrabool@bigpond.com

Project Eden: Fauna reintroductions, Francois Peron National Park, Western Australia

Per Christensen, Colleen Sims and Bruce G. Ward

Key words. Ecological restoration, pest fauna control, captive breeding, foxes, cats.

Figure 1. The Peron Peninsula divides the two major bays of the Shark Bay World Heritage Area, Western Australia.

Figure 1. The Peron Peninsula divides the two major bays of the Shark Bay World Heritage Area, Western Australia.

Introduction. In 1801, 23 species of native mammals were present in what is now Francois Peron National Park. By 1990 fewer than half that number remained (Fig 1.). Predation by introduced foxes and cats, habitat destruction by stock and rabbits had driven many native animals to local extinction.

Project Eden was a bold conservation project launched by the WA government’s Department of Conservation and Land Management (CALM -now Dept of Parks and Wildlife) that aimed to reverse extinction and ecological destruction in the Shark Bay World Heritage Area.

The site and program. Works commenced in Peron Peninsula – an approx. 80 km long and 20 km wide peninsula on the semi-arid mid-west coast of Western Australia (25° 50′S 113°33′E) (Fig 1). In the early 1990s, removal of pest animals commenced with the removal of sheep, cattle and goats and continued with the control of feral predators. A fence was erected across the 3km ‘bottleneck’ at the bottom of the peninsula where it joins the rest of Australia (Fig 2) to create an area where pest predators were reduced to very low numbers.

Figure 2. The feral proof fence was erected at the narrow point where Peron Peninsula joins the mainland.

Figure 2. The feral proof fence was erected at the narrow point where Peron Peninsula joins the mainland.

Once European Red Fox (Vulpes vulpes) (estimated at 2500 animals) was controlled and feral Cat (Felis catus) reduced to about 1 cat per 100 km of monitored track, sequential reintroductions of five locally extinct native animals were undertaken (Figs 3 and 4).  These included: Woylie (Bettongia penicillata – first introduced in 1997), Malleefowl (Leipoa ocellata – 1997), Bilby (Macrotis lagotis – 2000), Rufous Hare-wallaby (Lagorchestes hirsutus – 2001), Banded Hare-wallaby (Lagostrophus fasciatus -2001), Southern Brown Bandicoot (Isoodon obesulus – 2006) and Chuditch (Dasyurus geoffroi geoffroi -2011?)

Methods. Cat baiting involved Eradicat® cat baits, which were applied annually during March–April at a density of 10 to 50 baits/km2. Cat baiting continued for over 10 years, supplemented with a trapping program, carried out year round over a 8 -year period. Cat trapping involved rolling 10 day sessions of leghold trapping along all track systems within the area, using Victor Softcatch No. 3 traps and a variety of lures (predominantly olfactory and auditory).Tens of thousands of trap nights resulted in the trapping of up to 3456 animals. Fox baiting involved dispersal of dried meat baits containing 1080 poison by hand or dropped from aircraft across the whole peninsula. Baiting of the peninsula continues to occur annually, and removes any new foxes that may migrate into the protected area and is likely to regularly impact young inexperienced cats in the population, with occasional significant reductions in the mature cat population when environmental conditions are favourable.

Malleefowl were raised at the Peron Captive Breeding Centre from eggs collected from active mounds in the midwest of Western Australia. Woylies were reintroduced from animals caught in the wild from sites in the southwest of Western Australia, with Bilbies sourced from the Peron Captive Breeding Centre, established by CALM in 1996 to provide sufficient animals for the reintroductions. The centre has since bred more than 300 animals from five species

Monitoring for native mammals involved radio-tracking of Bilbies, Woylies, Banded Hare Wallabies, Rufous Hare-Wallabies, Southern Brown Bandicoots, Chuditch and Malleefowl at release, cage trapping with medium Sheffield cage traps and medium Eliots, as well as pitfall trapping of small mammals. The survey method for cats utilized a passive track count survey technique along an 80 km transect through the long axis of the peninsula. The gut contents of all trapped cats were examined.

Fig. 3. Woylies were first introduced in 1997 from animals caught in the wild at sites in southwest Western Australia.

Figure 3. Once foxes were controlled and cats reduced to about 1 cat per 100 km of monitored track, sequential reintroductions of five locally extinct native animals were undertaken. Woylies were first introduced in 1997 from animals caught in the wild at sites in southwest Western Australia.

Once European Red Fox (Vulpes vulpes) (estimated at 2500 animals) was controlled and feral Cat (Felis catus) reduced to about 1 cat per 100 km of monitored track, sequential reintroductions of five locally extinct native animals were undertaken.

Figure 4. Tail tag being fitted to a Bilby. (Bilbies were re-introduced to the Peron Peninsula in 2000, from animals bred in the Peron Captive Breeding Centre.)

Results. Monitoring has shown that two of the reintroduced species – the Malleefowl and Bilby – have now been successfully established. These species are still quite rare but they have been breeding on the peninsula for several years The Woylie population may still be present in very low numbers, but despite initial success and recruitment for six or seven years, has gradually declined due to prolonged drought and low level predation on a small population. Although the released Rufous Hare-wallabies and the Banded Hare-wallabies survived for 10 months and were surviving and breeding well, they disappeared because of a high susceptibility to cat predation and other natural predators like wedge-tailed eagles. Although some predation of Southern Brown Bandicoot has occurred and the reintroduction is still in the early stages, this species has been breeding and persisting and it is hoped that they will establish themselves in the thicker scrub of the peninsula.

Lessons learned. We found that the susceptibility to predation by cats and foxes varies considerably between species. Malleefowl are very susceptible to fox predation because the foxes will find their mound nests, dig up their eggs up and eat them – consequently wiping them out over a period of time. As cats can’t dig, Malleefowl can actually exist with a fairly high level of cats. Bilbies live in their burrows and are very alert so they can persist despite a certain level of cats. But the Rufous Hare-wallaby and the Banded Hare-wallaby are very susceptible to cat predation and fox predation due to their size and habits.

Examination of the period of time when species disappeared from the Australian mainland showed that there was a sequence of extirpations, reflecting the degree to which the species were vulnerable to pest predators. The ones that survived longest are those that are less vulnerable. This suggests that if complete control of predators is not possible (considering cat control is extremely difficult), it is preferable to focus on those animals that are least vulnerable. While it could be argued that reintroductions should be delayed until such time as all the cats and foxes have been removed, such a delay (which might take us 10, 20 or even 100 years) is likely to exceed the period of time many of these species will survive without some sort of assistance. It is likely to be preferable to proceed with reintroductions although we might be losing some animals.

Future directions. As with the majority of mainland reintroduction projects, level of predator control is the key to successful establishment of reintroduced fauna. The Project is currently under a maintenance strategy and future releases, which included the Western Barred Bandicoot (Perameles bougainville), Shark Bay Mouse (Pseudomys fieldi), geoffroi), Greater Stick-nest Rat (Leporillus conditor) and Red-tailed Phascogale (Phascogale calura) are on hold until improved cat control techniques are available. Despite the uncertain future for reintroductions of these smaller species, ongoing feral animal control activities and previous reintroductions have resulted in improved conditions and recovery for remnant small native vertebrates (including thick billed grass wrens, woma pythons and native mice), and new populations of several of the area’s threatened species which are once again flourishing in their original habitats.

Acknowledgements: the program was carried out by Western Australia’s Department of Parks and Wildlife and we thank the many Departmental employees, including District and Regional officers for their assistance over the years, and the many, many other people that have volunteered their time and been a part of the Project over the years, for which we are very grateful.

Contact: Colleen Sims, Research Scientist, Department of Parks and Wildlife (Science and Conservation Division, Wildlife Research, Wildlife Place, Woodvale, WA 6026, Australia, Tel: +61 8 94055100; Email: colleen.sims@dpaw.wa.gov.au). Also visit: http://www.sharkbay.org.au/project-eden-introduction.aspx

Further detail and other work in WA:

Per E. S. Christensen, Bruce G. Ward and Colleen Sims (2013) Predicting bait uptake by feral cats, Felis catus, in semi-arid environments. Ecological Management & Restoration 14:1, 47-53.

Per Christensen and Tein McDonald (2013) Reintroductions and controlling feral predators: Interview with Per Christensen. Ecological Management & Restoration, 14:2 93–100.

 

Long Swamp, Discovery Bay Coastal Park, Victoria

Mark Bachmann

Key words: wetland restoration, Ramsar, hydrology, Glenelg River, drainage

Long Swamp is a 15 km long coastal freshwater wetland complex situated in Discovery Bay Coastal Park, approximately 50 km north-west from Portland in south-western Victoria. The wetland system supports a diverse suite of nationally threatened species and is currently undergoing a Ramsar nomination process. Despite its size, reserved status and impressive biodiversity values, including recognition on the Directory of Important Wetlands in Australia, the local community in Nelson had expressed concern for over a decade about the impact that two artificial outlets to the ocean were having on wetland condition. The outlets were cut during an era when the swamp was grazed, many decades before being dedicated as a conservation reserve in the 1970s.

The wetland originally discharged into the ocean via Oxbow Lake and the Glenelg River mouth at Nelson. These changes to hydrology caused an interruption of flows, contributing to a long-term drying trend within the wetland complex.    This was not immediately obvious to many as the gradual drying of wetlands in a natural area is often less noticeable than in a cleared agricultural area, driven by a seamless and gradual shift towards more terrestrial species within the composition of native vegetation (Fig. 1).

Figure 1. Shrub (Leptospermum lanigerum) encroachment into sedgeland underway in Long Swamp.

In 2012, Nature Glenelg Trust (NGT) became actively involved in Long Swamp, working closely with Parks Victoria, the Nelson Coast Care Group, and the Glenelg Hopkins CMA. The initial involvement was to undertake a scientific review of the aquatic ecological values that might be impacted by the ecological shifts anecdotally observed to be underway. This early work identified that the more remote artificial outlet to the sea (White Sands) had in fact naturally closed, with a dune forming in front of the former channel several years earlier during the Millennium Drought (c. 2005). This formed an area of aquatic habitat immediately upstream of the former outlet that is now home to a diverse native freshwater fish community, including two nationally threatened fish species, the Yarra Pygmy Perch (Nannoperca obscura) and Dwarf Galaxias (Galaxiella pusilla). This observation and other investigations led to the planning of a restoration trial aimed at regulating or possibly blocking the second and final artificial outlet at Nobles Rocks to increase the availability, diversity and connectivity of aquatic habitats throughout Long Swamp, in order to benefit a wide range of wetland dependant species.

As well as undertaking basic monitoring across a broad range of taxonomic groups (birds, vegetation, frogs), the project has a particular emphasis on native freshwater fish populations as a primary indicator of project success.

Figure 2 – Aerial view of Nobles Rocks artificial outlet, detailing the location of the three trial sandbag structures.

Figure 2 . Aerial view of Nobles Rocks artificial outlet, detailing the location of the three trial sandbag structures.

Figure 3 - NGT staff members celebrate the completion of the third and final sandbag structure with some of the many dedicated volunteers from the local community.

Figure 3. Nature Glenelg Trust staff members celebrate the completion of the third and final sandbag structure with some of the many dedicated volunteers from the local community.

Reversal of artificial outlet impact over three phases.

The first two stages of the restoration trial in May and July 2014 involved 56 volunteers from the community working together to construct low-level temporary sandbag structures, initially at the most accessible and technically feasible sections of drain under flowing conditions. Tackling the project in stages enabled us to learn sufficient information about the hydrological conditions at the site in 2014, before commencing the third and final stage of the trial in March 2015. On the 27th April 2015, the main structure was completed, following two days of preparation and nine days of sandbagging (using about 6,600 sandbags), which were put in place with the dedicated help of over 30 volunteers (see Figs 3 and 4). To achieve our target operating height, the structure was raised by a further 30 cm in August 2015.

A series of gauge boards with water depth data loggers were also placed at key locations in the outlet channel and upstream into Long Swamp proper, to monitor the change in water levels throughout each stage of restoration and into the future.

Fig 4a. Long swamp

Figure 4a. View of the Phase 3 Restoration Trial Structure location prior to construction in March 2015.

Fig 4b. Long swamp

Figure 4b. Same location in June 2015, after construction of the Restoration Trial Structure.

Results to date.

Water levels in the swamp immediately upstream of the final structure increased, in the deepest portion of Long Swamp, from 34 cm (in April 2015) to 116 cm (in early September 2015). Further upstream, in a shallower area more representative of the impact on Long Swamp in the adjacent wider area, levels increased from being dry in April 2015, 14 cm deep in May, through to 43 cm deep in early September 2015, as shown in Figure 5. This is a zone where the shrub invasion is typical of the drying trend being observed in Long Swamp, and hence will be an important long-term monitoring location.

To evaluate the response of habitat to short and longer-term hydrological change, we also undertook longer-term landscape change analysis through GIS-based interpretation of aerial photography. This showed that we have currently recovered approximately 60 hectares of total surface water at Nobles Rocks, not including larger gains across downstream habitats as a result of groundwater mounding, sub-surface seepage and redirected surface flows that have also been observed.  These initial results and longer-term outcomes for targets species of native plants and animals will be detailed fully in future reports.

Fig 5a. Long swamp

Figure 5a. Further inland in the swamp after the Phase 3 structure was complete, shown here in May 2015. Depth – 14 cm.

Fig 5b. Long swamp

Figure 5b. Same photopoint 4 months later in September 2015. Depth – 43 cm.

Lessons learned and future directions.Meaningful community participation has been one of the most critical ingredients in the success of this project so far, leading to a strong sense of shared achievement for all involved. Monitoring will continue to guide the next steps of the project, with the ultimate aim of informing a consensus view (among those with shared interest in the park) for eventually converting the trial structure to a permanent solution.

Acknowledgements. Project partners include Parks Victoria, Nelson Coast Care Group, the Glenelg Hopkins CMA and the Friends of the Great South West Walk. Volunteers from several other groups have also assisted with the trials. Grant funding was generously provided by the Victorian Government.

Contact. Mark Bachmann, Nature Glenelg Trust, PO Box 2177, MT GAMBIER, SA 5290 Australia, Tel +61 8 8797 8181, Mob 0421 97 8181, Email: mark.bachmann@natureglenelg.org.au  Web: www.natureglenelg.org.au

See also:

Video conference presentation

NGH newsletter – including a link to a video on the project

Bradys Swamp EMR short summary

Picanninnie Ponds EMR short summary

 

Brady Swamp wetland complex, Grampians National Park, Victoria

Mark Bachmann

Key words: wetland restoration, Wannon River, hydrology, drainage, Gooseneck Swamp

A series of wetlands associated with the floodplain of the Wannon River (Walker, Gooseneck, and Brady Swamps), situated approximately 12 km north east of Dunkeld in western Victoria, were partially drained from the 1950s onwards for grazing purposes (Fig 1). A portion of these wetlands was later acquired and incorporated into the Grampians National Park (and other peripheral reserves) in the mid-1980s, managed by Parks Victoria. However, the balance of the wider wetland and floodplain area remained under private ownership, creating a degree of uncertainty surrounding reinstatement of water regime – an issue that was left unresolved for over two decades.

Many years of planning work, including modelling studies and biological investigations by a range of organisations, never quite managed to adequately resolve the best way to design and progress wetland restoration work in this area. To address the impasse, at the request of the Glenelg Hopkins CMA in early 2013, Nature Glenelg Trust proposed a staged restoration trial process which was subsequently agreed to by landowners, neighbours, government agencies, and local community groups.

Figure 1. Image from the present day: showing artificial drains (red lines/arrows) constructed to drain Walker, Gooseneck and Brady Swamps, as it operated from the 1950s–2013.

Figure 1. Image from the present day: showing artificial drains (red lines/arrows) constructed to drain Walker, Gooseneck and Brady Swamps, as it operated from the 1950s–2013.

Trials and permanent works undertaken.

Initial trials. The restoration process began in August 2013 with the installation of the first trial sandbag weir structure to regulate the artificial drain at Gooseneck Swamp. Its immediate success in reinstating wetland levels led to similar trials being initiated at Brady Swamp and Walker Swamp (Fig. 2) in 2014.

Figure 2. The volunteer sandbagging crew at the artificial drainage outlet from Walker Swamp - August 2014.

Figure 2. The volunteer sandbagging crew at the artificial drainage outlet from Walker Swamp – August 2014.

Permanent works were ultimately undertaken to reinstate the breached natural earthen banks at Brady and Gooseneck Swamps (Figure 3), implemented by Nature Glenelg Trust in early 2015.

Figure 3a. Trial Structure on the Brady Swamp outlet drain in 2014

Figure 3b. The same view shown in Figure 3a, after the completion of permanent works in 2015

Results. The works have permanently reinstated the alternative, original watercourse and floodplain of the Wannon River, which now activates when the water levels in these wetlands reach their natural sill level. This is predicted to have a positive impact on a wide range of flora and fauna species.

Monitoring is in place to measure changes to vegetation and the distribution and status of key fauna species, such as waterbirds, fish and frogs. Due to drought conditions experienced in 2015, to is too early to describe the full ecological impact of the works at this time.

4. Gooseneck Swamp in Sept 2014: the second season of the restoration trial, just prior to the implementation of permanent restoration works

Figure 4. Gooseneck Swamp in Sept 2014: the second season of the restoration trial, just prior to the implementation of permanent restoration works

Lessons learned. The success of these trials has been based on their tangible ability to demonstrate, to all parties involved, the potential wetland restoration outcome for the sites; made possible by using simple, low-cost, impermanent methods. To ensure the integrity of the trial structures, the sandbags used for this purpose are made of geotextile fabric, with a minimum field service life of approximately 5 years.

The trials were critical for building community confidence and collecting real operational data for informing the development of longer-term measures to increase the depth and duration of inundation.

A vital aspect of the trials has been the level of community participation, not only at the sandbagging “events”, but also the subsequent commitment to ecological monitoring, for helping evaluate the biological impacts of hydrological reinstatement. For example, the Hamilton Field Naturalists Club has been undertaking monthly bird monitoring counts that are helping Nature Glenelg Trust to develop a picture of the ecological value of these wetlands and their role in the wider landscape, including the detection of international migratory species.

Acknowledgements. Project partners include Parks Victoria, Hamilton Field Naturalists Club, the Glenelg Hopkins CMA, Macquarie Forestry and other private landholders. Volunteers from several other groups have also assisted with the trials. Grant funding was generously provided by the Victorian Government.

Contact. Mark Bachmann, Nature Glenelg Trust, PO Box 2177, MT GAMBIER, SA 5290 Australia. Tel +61 8 8797 8181, Mob 0421 97 8181; Email mark.bachmann@natureglenelg.org.au. Web| www.natureglenelg.org.au

See also:

Long Swamp EMR short summary

Picanninnie Ponds EMR short summary

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