Category Archives: Standards

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

Victorian Northern Plains Grasslands Protected Area Network: formation and future management

Nathan Wong

Key words: ecosystem decline, conservation planning, grassland restoration, threatened species

Building the network. Since the early 1990s Trust for Nature (Victoria) (TfN) in partnership with State and Federal government agencies and local land owners have been working to protect, restore and improve the condition and extent of Grasslands in the Victorian Riverina. This critically endangered ecosystem has been degraded, fragmented, and cleared over the past 200 years by a range of impacts largely associated with the exploitation of these areas for agricultural production. This use has resulted in the loss of over 95% of the original grassland extent in Victoria and the degradation of all remaining remnants.

The first major achievement of this program occurred in June 1997 when Trust for Nature acquired the 1277 ha ‘Davies’ property following many years of negotiations. This land was transferred to the Crown in April 1999 to form the Grassland section of what is now Terrick Terrick National Park. Since this initial acquisition a significant number of purchases have been added to the public estate with the support of both State and Federal National Reserve Systems Programs. These additions have resulted in Terrick Terrick National Park now covering over 3334ha (Table 1) and the establishment of Bael Bael Grasslands NCR during 2010 and 2011 which now covers 3119ha.

Running concurrently with this increase in the public estate has been a program to build and secure private land under conservation covenant as well as Trust for Nature establishing a number of reserves to build its private reserve network in the Victorian Riverina. These efforts have resulted in the addition of 2804ha owned by Trust for Nature, including Glassons Grassland Reserve (2001), Kinypanial (1999), Korrak Korrak (2001), Wanderers Plain (2009-2010) and 1036ha of private land protected under conservation covenant.

As a result of these efforts the area of grasslands within the Protected Area Network in the Victorian Riverine Plains has grown from virtually nothing in the mid-1990s, to in excess of 10,000ha and continues to expand.

OLYMPUS DIGITAL CAMERA

Fig 1. Very high quality Northern Plains Grasslands in Spring, note the inter-tussock spaces and diversity of flowering herbs (Photo: Nathan Wong).

Table 1. Acquisitions that have resulted in Terrick Terrick National Park, now covering over 3334ha.

Table 1

Current remnant condition. Whilst these grasslands are the best examples of the remaining ecosystem and protected under State and Federal government legislation, all of them have been degraded by past land-use. Therefore the need to not only protect but restore them is critical to the successful management of these systems in-perpetuity. Despite this past loss of a range of grazing-sensitive plant species many still persist in small isolated populations across the reserve network. Management of grazing, when it is applied, to ensure that continued losses do not occur whilst maintaining biodiversity values is one of the key aims of management. As a result of loss of quality, quantity and fragmentation of habitats, a range of important faunal species have also historically declined (Figs 2 & 3).

Need for management and restoration. There is great potential for management regimes to manipulate the composition of grasslands to enhance the likelihood of restoration success. Restoration of a range of grazing sensitive plant species which now either regionally extinct or remain in small isolated population will almost certainly require changes to grazing regimes, reintroduction of fire regimes and species reintroductions to ensure viable populations. Reintroducing faunal species will also require attention to connectivity and habitat availability issues in this context as many are dependent on the existence of large, interconnected territories e.g. Hooded Scaly-foot (Pygopus schraderi).

The Northern Plains Grasslands Protected Area Network: Strategic Operational Plan (SOP) is a landscape-scale strategic operational plan for the conservation management of the Northern Plains Grassland community within Victoria’s Protected Area Network, developed by the Northern Plains Technical Advisory Group in 2011. This Operational Plan now guides TfN and Parks Victoria in the implementation of an adaptive management plan for the landscape. This plan aims to establish and implement a restoration program across the public and private protected areas and is a marked shift from the previous management intent of maintenance of the system.

Fig 2. The area, particularly the Patho Plains and Lower Avoca, provide important habitat for the persistence of the Plains-wanderer (Photo David Baker-Gabb).

Fig 2. The northern plains grasslands, particularly the Patho Plains and Lower Avoca, provide important habitat for the persistence of the Plains-wanderer (Photo David Baker-Gabb).

Strategies for management and restoration. There are two main strategies that are being implemented. The first involves the extension of protected areas through a range of mechanisms; and the second involves active management to restore habitat quality and diversity to the extent possible.

Extent. Expansion of the current approach of reserve acquisition and covenanting that has been undertaken by the range of partners is likely to able to target and establish large areas (20,000+ ha) in the Lower Avoca and Patho Plains landscape. Both these areas are high priorities for Trust for Nature and form significant sections of the Trust for Nature’s Western Riverina Focal Landscape. The Patho Plains is significant as it is an Important Bird Area and a focus of Birdlife Australia to ensure the long term persistence of the Plains-wanderer (Pedionomus torquatus). The Lower Avoca also provides important habitat for the Plains-wanderer (Draft National Recovery Plan) and is one of the main population centres for Hooded Scaly-foot in Victoria.

Diversity. The increase of diversity and quality of these systems requires direct intervention in management as well as the introduction and establishment of the many rare and regionally extinct species from the system.

Plant species: Over the past decade, TfN and others have successfully trialled the reintroduction of a number of threatened and common plant species through hand sowing seed into grasslands. These species include: Hoary Sunray (Leucochrysum molle), Leafless Bluebush (Mairena aphylla), Rohlarch’s Bluebush (Maireana rohlarchii), Bladder Saltbush (Atriplex vesicaria), Plains Everlasting (Chrysocephalum sp. 1), Beauty Buttons (Leptorhynchos tetrachaetus), Small-flower Goodenia (Goodenia pusilliflora), Minnie Daisy (Minuria leptophylla) and a range of Wallaby species (Rytidosperma spp.) and Spear Grasses (Austrostipa spp.).

Animal species: Local habitat variability for a range of fauna has been achieved through the modification of grazing regimes and the introduction of burning regimes at a range of sites. This work aims to maximise niches and thus opportunities for a broad range of species.

Fig 3. Hooded Scaly-foot adult by Geoff BrownCOMP

Fig 3. Hooded Scaly-foot adult, a critically endangered legless lizard that occurs in the Northern Plains Grasslands, preferring habitat much like the Plains-wanderer. Photo: Geoff Brown.

Table 2.  Triggers required for various grazing and other management regimes to maintain appropriate intertussock spaces in Northern Plains Grasslands

Table2

Monitoring. The SOP includes a method for rapid assessment of habitat and functional composition of sites to support decision making and track habitat change over time. This is stratified by soil type as grazing and habitat values and floristic communities vary between soil types within the grassland mosaic. Triggers for action or management bounds have been set based on the structure of inter-tussock spaces on red soils. These have been established using the “Golf ball” method which calculates a golf ball score by randomly dropping 18 golf balls into a 1m x 1m quadrat and then establishing a count based on the visibility of the golf balls (>90% visible = 1, 90%-30% visible = 0.5, <30% visible = 0). For red soil grasslands the aim is to maintain the inter-tussock spacing within a golf ball range of 13-16 using the range of tools identified in Table 2. When a paddock reaches a golf ball score of 16 and it is being grazed, stock are to be removed. When the paddock reaches a score of 13 they are then to be reintroduced, within the bounds of the regime that is to be applied.

Additional to this there has also been collection of data in relation to the functional composition of sites with golf ball quadrats also assessed for the presence of a range of functional groups including Native C4 grasses, Native C3 Grasses, Exotic annual grasses, Exotic Perennial Grasses, Native forbs, Exotic Forbs, Native Shrubs, Moss cover, Other Crytptograms (i.e. Lichen, Algae, Liverworts), Bare Ground and Litter. At all these sites photos are also taken of each quadrat with and without golf balls and a landscape photo is also taken.

The capturing of these data and the region wide approach across both public and private areas will increase our knowledge of how to manage and restore these important sites as well as track progress of management actions and their effectiveness in providing protected areas for a range of threatened species.

Acknowledgements. A wide range of partners and individuals are involved in the protection of the Northern Plains Grassland and the development of the Northern Plains Strategic Operations Plan including Parks Victoria, Department of Environment, Land, Water & Planning (DELWP), La Trobe University, Charles Sturt University, Arthur Rylah Institute for Environmental Research, North Central Catchment Management Authority, Northern Plains Conservation Management Network, Elanus Consulting and Blue Devil Consulting.

Contact: Nathan Wong, Conservation Planning Advisor, Trust for Nature (Level 5, 379 Collins Street, Melbourne VIC 3000, Australia;Tel: +61 (0)3 8631 5888; Freecall: 1800 99 99 33; Mob 0458 965 329;Email: nathanw@tfn.org.au, www.trustfornature.org.au).

 

 

 

Update of landowner and community engagement in Regent Honeyeater Habitat Restoration Project – Lurg Hills, Victoria

Ray Thomas

Key words: community engagement, environmental education, habitat restoration

The Regent Honeyeater Project in the Lurg Hills, near Benalla in Victoria, is a habitat restoration project that emphasises that a key to biodiversity conservation is working well with the people who live in the landscape.  In fact the biodiversity gains in the 21 years of remnant protection, plantings and habitat provision in the Lurg Hills, would not have been possible without the support of landowners (who have given their land, their enthusiasm and time to the project) and the many community groups and individuals who come to help with the plantings.  The latest update on landowner and community engagement quoted from the  March 2016 update is as follows.

Increased social engagement. In the last 6 years we have increased the number of visits to planting days by 50 per cent. There has been a steady growth in the number of new local landholders involved and the total number is now 160 landholders engaged, compared with 115 in 2009. Everyone we come across knows of the project and anyone new to the area hears about it from one of their neighbours. Very few people (you could count them on one hand), say they would rather not be involved. In fact we increasingly get cold calls from new people who have observed what has happened on their neighbour’s place and then phone us to say they want to be involved. It’s a positive indication that the project is part of the spirit of the area. This was further confirmed by the inclusion, of a very detailed Squirrel Glider (Petaurus norfolcensis) mural in a recent street art painting exhibition. The permanent artwork is the size of a house wall, and situated prominently in the heart of the parklands of Benalla.

Much of our work has relied heavily on volunteers, with a total of 10,344 students and 24,121 community volunteers involved over the past 21 years. City folk have fewer opportunities to be in nature, with the bushwalking clubs, university students and scouts in particular, really keen to come and roll up their sleeves.

Typically about 17 to 20 of the local schools, primary and secondary, help us with propagating the seedlings at the start of each year and then planting their own seedlings back out into the field in the winter and spring. And we are increasingly getting interest from metropolitan schools that come to the country for a week-long camp. Some of the schools even have their own permanent camps up here and they want to be involved with our hands on work too. “It’s simply part of our environmental responsibility”, is the way they express it.

Contact: Ray Thomas, Coordinator of the Regent Honeyeater Project Inc (PO Box 124, Benalla, Vic. 3672, Australia; Tel: +61 3 5761 1515. Email: ray@regenthoneater.org.au

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Penrhyn Estuary Habitat Enhancement Plan: Habitat Rehabilitation for Migratory Shorebirds in Botany Bay, NSW

Peggy O’Donnell

Keywords: estuarine, restoration, saltmarsh, seagrass, roosting habitat, feeding habitat

Introduction: The Penrhyn Estuary Habitat Enhancement Plan (PEHEP) is an ambitious rehabilitation project undertaken to compensate for habitat loss due to the expansion of Port Botany. Development in Botany Bay, NSW, has caused substantial biophysical changes since the 1940s. Shorebird habitat has decreased due to airport development and expansion and Foreshore Beach is greatly reduced. Penrhyn Estuary is the only remaining significant shorebird roosting and feeding habitat along the northern shoreline but has legacy pollution. The PEHEP was prepared as part of development approval and implemented from 2012 to 2017.

Figure 1: Penrhyn Estuary 2008, before port expansion.

Figure 1: Penrhyn Estuary 2008, before port expansion.

Figure 2: Penrhyn Estuary 2015, four years after port expansion works.

Figure 2: Penrhyn Estuary 2015, four years after port expansion works.

Broad aims and works: The PEHEP aims to rehabilitate the estuary by expanding roosting and feeding grounds for migratory shorebirds and thereby increase their populations in line with Australia’s international responsibilities for shorebird conservation. Key works included levelling of sand dunes to create saltmarsh habitat and expansion of existing intertidal sand flats by filling deeper parts of the estuary with dune sand. A flushing channel was constructed to ensure adequate tidal exchange and to provide habitat suitable for seagrass beds. Protected seagrass, Strapweed (Posidonia australis) was transplanted prior to works and remaining Eelgrass (Zostera capricorni) and Paddleweed (Halophila ovalis) were protected from damage during construction using silt curtains. Local saltmarsh species planted were optimal for use as roosting habitat and extensive weed removal and maintenance was undertaken. Sound barriers, lighting and fencing around the estuary and port structure were designed to favour shorebirds and deter predators.

Monitoring programs compared baseline and post-rehabilitation conditions to assess rehabilitation efficacy. Surveys were done within the estuary and at appropriate reference locations within a BACI experimental design framework. Indicators included: abundance of key shorebird species, benthic infaunal communities, planted and transplanted saltmarsh, remnant and transplanted seagrasses off Foreshore Beach, and water quality.

Results to date:

Water Quality. Four years after habitat enhancement, physiochemical properties (temperature, pH, dissolved oxygen, salinity, total suspended solids, key nutrients) and a productivity indicator (chlorophyll a) were not significantly different from pre-construction or reference values. The configuration of the flushing channel simulated modelled estuary flushing times No algal blooms have been identified to date, suggesting the absence of eutrophic conditions within the now shallower estuary.

Saltmarsh habitat. After planting propagules the total area of saltmarsh habitat in Penrhyn Estuary exceeds 40,000 m2, a 76% increase post port construction and habitat creation (see Sainty 2016 and Dalby-Ball & Olsen 2016 for details of saltmarsh design and planting methodology). Following the works, saltmarsh species diversity, abundance and condition all improved.

The newly-planted saltmarsh vegetation appeared healthy showing continued growth with variability mainly at the margins of planted beds. The main roosting habitat species Salt Couch (Sporobolus virginicus) increased in all treatments, while Seablight (Suaeda australis) decreased slightly consistent with its removal in strategic locations to maintain plant height favourable for shorebird roosting habitat. The ecological function of planted saltmarsh areas was similar to that at reference locations (including other constructed saltmarsh habitats) and a trend of increasing biodiversity was observed throughout the three post-rehabilitation surveys. Some habitats treatments have not responded as well, including those transplanted prior to enhancement works and areas that were cleared of mangroves and weeds. Overall, the majority of ecological targets set with respect to the saltmarsh vegetation within Penrhyn Estuary were met.

Benthic intertidal habitat. Unvegetated intertidal feeding habitat for migratory shorebirds increased by 307% as a result of filling deeper parts of the estuary with dune sand. To enhance invertebrate abundance and diversity, dune sand was augmented with seagrass wrack and river mud as it was profiled in the estuary. Earthworks were staged such that tidal exchange with Botany Bay was altered and/or restricted but never eliminated during the two year construction period.

Criteria for the success of habitat creation were derived from comparison to target values based on pre-enhancement surveys and reference locations. Physical indicators were median grain size and percentage of fine sediments (% clay and silt fractions). Biological indicators were invertebrate abundance and biomass.

After habitat enhancement targets for invertebrate biomass were exceeded, but were not significantly different to those at reference locations. Invertebrate abundance reached only 61% of the target value and decreases resembled those in reference locations. Median grain size and percentage fines in newly created sand habitats were similar to pre-enhancement levels.

The taxonomic composition of benthic assemblages shifted post enhancement. Polychaete worms were characteristic of the assemblage before enhancement while gastropods and bivalve molluscs drove assemblage patterns after enhancement. Polychaetes declined from 76% of all invertebrates before enhancement to 47% after, while molluscs increased from 16% before to 49% after.

Seagrass habitat. Prior to construction, seagrasses off Foreshore Beach had undergone a significant natural decline. Strapweed patches within the footprint of the new boat ramp were transplanted to southern Botany Bay and are now indistinguishable from local plants. Condition of remaining seagrass patches off Foreshore Beach was monitored as was recolonization in the created flushing channel and lower reaches of the estuary.

Three post–construction monitoring surveys have documented a narrow, large bed of Paddleweed containing small patches of Eelgrass and Strapweed that extends off Foreshore Beach in 2-3 m water depth. Small isolated patches of Eelgrass and Strapweed persist at Foreshore Beach. Post-construction conditions are suitable for their survival and larger seagrass beds may be able to re-establish given normal processes of succession. Although numerous patches of the colonising Paddleweed and Eelgrass have been recorded in the flushing channel and in the inner estuary, typically these have not persisted. Turbidity may be limiting light penetration to the deeper parts of the flushing channel and offshore movement of sediments may be smothering seagrasses in the shallower areas of the flushing channel before they can fully establish.

Shorebird populations. Six key species of shorebirds were selected to indicate the success of the rehabilitation project: Bar-tailed Godwit (Lamosa lapponica), Red-necked Stint (Calidris ruficollis), Double-banded Plover (Charadrius bicinctus), Curlew Sandpiper (Calidris ferruginea), Red Knot (Calidris canutus) and Pacific Golden Plover (Pluvialis fulva). Abundance, diversity, health and habitat usage were monitored for these species and compared to target numbers derived from pre-construction data in 2006, as well as counts at reference sites. The frequency and sources of disturbance and observations on predation were recorded in peak and off-peak seasons.

The population of Pacific Golden Plover appears to be responding positively to the works, with the target exceeded in five consecutive seasons. Mean numbers of Double-banded Plover have increased at Penrhyn Estuary throughout both tidal phases, though is yet to meet its target peak count. Bar-tailed Godwit and Red-necked Stint have declined in this period, and there were no sightings of Red Knot or Curlew Sandpiper in the 2015 peak season surveys.

Disturbances to shorebirds in Penrhyn Estuary have been reduced with the completion of the sound barrier around the port side perimeter and exclusion of the public. Predation was high in the peak 2014 season, emphasising the need to control foxes and cats.

Monitoring reports for the PEHEP are available at:

http://www.sydneyports.com.au/sustainability/penrhyn_estuary_rehabilitation/monitoring_and_reporting2

Lessons learned and future directions:

  • Achievement of the desired profile for the site based on modelling and watering of saltmarsh plants in the initial stages likely set the stage for the success in establishing the large tracts of saltmarsh habitat. The initial removal and subsequent maintenance of a mangrove-free estuary, including a floating trash boom is supporting regular weed removal to improve the chances of long-term sustainability.
  • The relatively poorer response of transplanted saltmarsh areas, and those weeded but otherwise undisturbed suggests that for large habitat creation projects, propagating and planting local saltmarsh species is an efficient, appropriate approach the showed good results in the short term.
  • Earth moving works were staged such that the tidal exchange within the inner estuary was never completely blocked. This is likely to be a factor in the rapid reestablishment of benthic invertebrates, whose pattern of succession and composition differs from those reported for similar projects. Together with the improvement of dune sand by the addition of seagrass wrack and river mud, the fundamentals for a sustainable feeding habitat for shorebirds have been laid.
  • Tidal erosion removed a small portion of saltmarsh habitat along the inner estuary margin which was reshaped and repaired without further habitat damage or disturbance to roosting birds. The lesson: despite careful planning, erosive forces can alter habitats unpredictably as created habitats mature, and timely adaptive management is required to rectify damage and reduce further loss.
  • Shorebird populations and invertebrate abundance in the first two years of post-construction monitoring showed a generally positive correlation and similar trajectories of, suggesting that created intertidal habitat provided sufficient prey items to support increased shorebird populations in the longer term, despite considerable variability and failure of both populations to meet some target indicators. The abundance, biomass and community composition of benthic invertebrates in the most recent sampling (November 2014) fell within the range of variation seen in the five previous sampling events, however overall shorebird abundance fell to a minimum. Shorebird observations for the three months up to March 2015 showed an increasing trend, however targets for all but one species (Pacific Golden Plover) have not been achieved.

Comparisons to data from reference locations suggest that some factors may be operating at a range of spatial scales observable along the east coast of Australia. For all but Bar-tailed Godwit they suggest an overall decrease in key migratory species that is not limited to Penrhyn Estuary. Predation (or displacement due to presence of predators) may reduce the population of some shorebirds at some times, but no observations suggest that habitat quality, including roosting habitat and availability of prey items deter or limit the level of shorebird habitat use in Penrhyn Estuary.

Stakeholders and Funding bodies: Port Authority of NSW (Formerly Sydney Ports Corporation) fund and manage all aspects of the project, beginning with EIS studies and construction through to ongoing maintenance and monitoring. NSW Ports provides funding for ongoing maintenance and monitoring. Shorebird monitoring was done by as subcontract to Cardno (NSW/ACT) by Avifauna Research & Services, Email www.avifaunaresearch.com.au

Contact information: Dr Peggy O’Donnell Practice Lead Ecology, Water & Environment, Cardno (NSW/ACT). Tel: +61 2 9496 7700 Mobile +61 422 858 827. Postal PO Box 19, St Leonards NSW 1590. Email peggy.odonnell@cardno.com.au

WATCH VIDEO: Peggy O’Donnell 2014 pesentation to AABR seminar

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