Category Archives: Coastal & marine

Seagrass rehabilitation and restoration, Cockburn Sound, WA

Key words. Coastal ecosystems, transplanting trials, compensatory restoration, Posidonia

Introduction. Seagrasses are flowering plants that form extensive underwater meadows, transforming bare sandy areas into complex 3-dimensional habitats for a diverse faunal community. They provide a wide range of ecosystem services including nutrient cycling, carbon sequestration, and coastal stabilization. Once impacted, seagrass meadows can take decades to recover.

The need for seagrass restoration is mainly driven by loss of seagrass due to human activities including ocean discharges and coastal developments, although changing ocean conditions (warming temperatures and increasing acidity) and sea-level rise now provide additional challenges.

 Posidonia australis, from planting unit to spreading and merging shoots.

Figure 1. Posidonia australis showing spreading and merging shoots from what were initially only single planting units (see inset).

Cockburn Sound project. In 2003, the Seagrass Research and Rehabilitation Plan (SRRP) was established to meet stringent environmental management conditions for two separate industrial development projects in Cockburn Sound, Western Australia. Both projects, Cockburn Cement Ltd and the state Department of Commerce, impacted upon seagrass ecosystems.

The SRRP was aimed at developing and implementing seagrass restoration procedures that are economically feasible and environmentally sustainable. The collaborative project team was coordinated by BMT Oceanica and included researchers from Murdoch University, The University of Western Australia, Edith Cowan University, the Botanic Gardens and Parks Authority, environmental consultants and a marine engineering firm.

Works and their results. Implementing the SRRP involved a range of experimental transplantings of the seagrass Posidonia australis (a slow-growing meadow-forming species).

The transplant trials resulted in good health and high survival rates of transplanted shoots. This showed that meadows can be restored and thus are likely to develop and return to the same ecological functions as natural meadows.

In this case, donor material was harvested from a site that was to be destroyed as part of the permitted development. In other cases, donor material has been harvested from meadows that have demonstrated varying levels of recovery, with a number of years required for recovery depending on the intensity of harvesting. The project resulted in site-specific solutions as well as generic technical guidelines for manual transplantation to restoration sites from donor sites.

Lessons and limitations. The main lessons for practice to date are:

  • While the results of this project are encouraging, the challenge of achieving biological diversity in seagrass meadows, particularly to the equivalence of a natural seagrass meadow, has not yet been demonstrated.
  • The scale of this particular project is still small (3.2 Ha) relative to the amount of restoration required. Focus needs to be on research into how such projects can be scaled-up. Seed-based restoration may be more appropriate for some species (including Posidonia).
  • Selection of a restoration site is a strong factor contributing to the success of transplanted material (i.e. the likelihood of success if higher where seagrass was present before).

Contact. Dr Jennifer Verduin, lecturer, Murdoch University , Tel: +61 8 93606412/0404489385; Email: j.verduin@murdoch.edu.au

Also see:

EMR project summary – report on the seagrass transplanting trials:

Full EMR feature article

 

East Trinity remediation and rehabilitation after Acid Sulfate Soil contamination, north Queensland

Hanabeth Luke

Key words. Mangroves, estuarine habitat, migratory waders, ecological conversion

Introduction. The East Trinity case study describes the remediation of a severely degraded coastal acid sulfate soil site adjacent to the Cairns township in Queensland, Australia (Fig 1). The project involved extensive collaborative research into geochemistry, soil properties, groundwater and tidal behaviour, terrain modelling and flood modelling by a range of institutions. An innovative strategy known as lime-assisted tidal exchange (LATE) was used to reverse the acidification of the wetland, leading to improved water quality and health of coastal and estuarine ecosystems.

Acid sulfate soils are formed through a natural process that occurred when coastal lowlands were flooded in periods of high sea-level, leading to a slow build-up of metal sulfides such as pyrite. When these soils, normally protected by natural wetlands, are drained for farming or other development and exposed to oxygen, rapid oxidation of the pyrite occurred. This leads to a build-up of acidity in the soil as oxidation processes produce sulfuric acid, releasing toxic metals and noxious gases creating hostile conditions for plant growth. The acid also affects the availability of nutrients in the soil, creating another challenge for plant life. Rainfall events cause the acid, metals and nutrients to drain into waterways, impacting on aquatic ecosystems, infrastructure, fisheries and potentially, human health.

Figure 1. Aerial photo of he location of the East Trinity coastal and acid sulfate soil rehabilitation site (Source: Landsat 1999).

Figure 1. Aerial photo of he location of the East Trinity coastal and acid sulfate soil rehabilitation site (Source: Landsat 1999).

Prior condition and the degradation phase. East Trinity is a 940 ha coastal wetland situated between important estuarine habitats and a World Heritage listed wet tropical rainforest. Prior to clearing for farming, it was a mixture of paperbark woodland, tidal mangrove and salt marsh and had high ecological value for both marine and terrestrial faunal species. The area formed part of the traditional territory of the local Indigenous Mandingalbay Yidinji people.

The site was developed for sugar cane farming in the 1970s, with a bund-wall built to halt tidal inundation of the site. This drainage led to the oxidation of soil materials and a build-up of sulfuric acid in the sediments. A range of CSIRO and other reports showed that this affected 720 ha of the 940ha site. Between 1976 and 2004, it was estimated that at least 72,000 tonnes of sulfuric acid was released from the site, as well as soluble aluminium, iron, heavy metals and arsenic. Water bodies on site were routinely found to have a pH of 3.5 or lower. Aluminium levels were of particular concern, exceeding ANZECC guideline levels by as much as 6,000 times.

The discharge of acid and heavy metals led to death and dieback of vegetation (Figs 2 and 3) and had severe implications for aquatic life. These impacts were of particular concern due to the proximity of the site to the Great Barrier Reef Marine Park, with substantial evidence that acid sulfate soil runoff was discharging into reef receiving waters.

Figure 2a: Aerial view of Firewood Creek area from the 1980s showing extensive grasslands and Melaleuca leucadendra woodlands to the left of the bund wall roadway

Figure 2a: Aerial view of Firewood Creek area from the 1980s showing extensive grasslands and Melaleuca leucadendra woodlands to the left of the bund wall roadway.

Figure 2b: Aerial view of Firewood Creek area in 2013 with extensive flooded areas, Melaleuca woodland die-back and mangrove development.

Figure 2b: Aerial view of Firewood Creek area in 2013 with extensive flooded areas, Melaleuca woodland die-back and mangrove development.

Fig 3. Iron accumulation in oxidised sediments at the East Trinity site.

Fig 3. Iron accumulation in oxidised sediments at the East Trinity site.

Remediation, rehabilitation and restoration phase. The land was purchased by the QLD government in the year 2000, with the ‘Acid Sulfate Soil Remediation Action Plan’ commencing shortly thereafter. This involved a range of engineering solutions to achieved the desired hydrology and apply the lime-assisted tidal exchange remediation strategy, at first on a trial basis. Positive results during the trial period led to the long-term adoption of lime assisted tidal exchange (LATE) at East Trinity.

The LATE remediation strategy. Management strategies for acid sulfate soils are based on the principles of dilution, containment or neutralisation, with each bringing different benefits and challenges. Containment can lead to substantial acid build up and inhibit the movement of aquatic life, whilst the addition of agricultural lime can be costly. The LATE strategy (Fig. 4) was designed to support natural processes by reintroducing tidal flows, encouraging natural systems to restore the wetlands, hence greatly reducing the costs of lime and infrastructure, as well as hands-on management requirements. Flooding the soil stimulated reducing geochemical conditions whilst diluting the acidity. The bicarbonate in seawater provided a large source of alkalinity, whilst the organic matter present provided energy for microbial reactions to take place in the soil, thereby stimulating the in-situ production of alkalinity. Agricultural lime was added to the incoming tide to support the process, and also added to the out-going exit waters to prevent acid-flush into estuarine waters.

Fig 4. The image above shows some of the key parameters improved by the LATE bioremediation strategy.

Fig 4. The image above shows some of the key parameters improved by the LATE bioremediation strategy.

Results of the remediation project. The East Trinity site now has sediments at a spectrum of stages of remediation, with large areas fully remediated. Tidal inundation has ultimately led to a binding-up of heavy metals in the sediments and the neutralisation of acidity to a pH of 6.5, a typical pH for a subtropical estuarine environment. Following six years of gradually increasing tidal inundation, it was found that in-situ microbial and tidal exchange processes accounted for 99% of the change, whilst the addition of agricultural lime contributed less than 1%.

This greatly reduced the release of heavy metals to the estuarine environment and allowed for the re-establishment of mangrove and intertidal ecosystems (Fig. 2b).

Vegetation. Some ecological communities associated with the incursion of seawater and expansion of the tidal zones within the site have reduced while others have expanded. Mangrove communities have expanded and Acrostichum aureum (mangrove fern) fernlands have particularly increased, although some previous fernland transitioned to mangrove. Pasture areas have been largely replaced by Paperbark (Melaleuca leucadendra) shrublands and low woodlands and by the native grass Phragmites (Phragmites karka). The dieback of open forests of Paperbark impacted by the tidal areas continues, with some stands that were healthy in 2008 now in decline. Decline of low Clerodendrum inerme closed vinelands also continues in proximity to the tidal zone, though in other areas this community appears to be recovering.

Birds. A total of 136 species of birds have been observed at East Trinity since the rehabilitation began. Reports suggest that the expansion of mangrove and other higher elevation wetlands associated with the rehabilitation are likely to have benefited a number of bird species, including some internationally important shorebird species listed in agreements with China (CAMBA), Japan (JAMBA) and the Republic of Korea (ROKAMBA). Recently a new wader roosting site has emerged in mangroves on the northern boundary of the East Trinity area and it seems this may be significant in the regional context.

Future directions. The remediation of the East Trinity site has led to the area now having sufficiently high ecological function to be transferred back to Indigneous ownership and management.

The LATE remediation strategy’s regular tidal inundation will remain in place to ensure the acid sulfate soils remain protected from further oxidation; and monitoring and further research will continue into geochemical pathways to avoid degradation re-occurring.

Acknowledgements. The remediation of the East Trinity site and subsequent research has occurred due to the long-term efforts and collaborations between the Queensland Department of Science, Information Technology and Innovation (DSITI), CSIRO, the CRC for Contamination Assessment and Remediation of the Environment (CRC CARE) and Southern Cross University. Figures and data cited in this summary are derived from reports from these organisations available on request.

Contact. Prof Richard Bush, University of Newcastle (University Drive, Callaghan NSW 2308, Australia Tel: +61 (0)2 49215000; Email: richard.bush@newcastle.edu.au) .  Hanabeth Luke is an Associate Lecturer, Southern Cross University (Lismore, NSW 2480, Australia. Tel: +61 (0) 430092071; Email: Hanabeth.luke@scu.edu.au).

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).

Conserving and restoring biodiversity of the Great Barrier Reef through the Representative Areas Program (RAP)

Key words: Coral reef, no take zones,

The Great Barrier Reef is the world’s largest coral reef ecosystem (344,400 square km) and a World Heritage Area on the north-east coast of Australia. It contains a high diversity of endemic plants, animals and habitats. It is a multiple-use area with different zones in which a wide range of activities and uses are allowed, including tourism, fishing, recreation, traditional use, research, defence, shipping and ports. Components of the ecosystem have been progressively showing symptoms of decline.

TroutBarra3

Coral Trout is one of more than 1625 fish found on the Great Barrier Reef

Existing ecosystems. Coral reefs are like the building blocks of the Great Barrier Reef, and comprise about seven per cent of the ecosystem. The balance is an extraordinary variety of other marine habitats and communities ranging from shallow inshore areas to deep oceanic areas over 250 kilometres offshore and deeper than 1000 metres, along with their associated ecological processes. The abundant biodiversity in the Great Barrier Reef includes:

  • Some 3000 coral reefs built from more than 400 species of hard coral
  • Over one-third of all the world’s soft coral and sea pen species (150 species)
  • Six of the world’s seven species of marine turtle
  • The largest aggregation of nesting green turtles in the world
  • A globally significant population of dugongs
  • An estimated 35,000 square kilometres of seagrass meadows
  • A breeding area for humpback whales and other whale species
  • More than 130 species of sharks and rays
  • More than 2500 species of sponges
  • 3000 species of molluscs
  • 630 species of echinoderms
  • More than 1625 species of fish
  • Spectacular seascapes and landscapes such as Hinchinbrook Island and the Whitsundays
  • 215 species of bird
Crown-of-thorns single injection (C) GBRMPA cropped

Diver injecting Crown of Thorns Starfish

Impacts on the ecosystem. The main threats to the Great Barrier Reef ecosystem are:

  • Climate change leading to ocean acidification, sea temperature rise and sea level rise
  • Catchment run-off of nutrients, pesticides and excessive sediments
  • Coastal development and associated activities such as clearing or modifying wetlands, mangroves and other coastal habitats
  • Overfishing of some predators, incidental catch of species of conservation concern, effects on other discarded species, fishing of unprotected spawning aggregations, and illegal fishing.
4. GBRMPA staff - public consultation(2)

GBRMPA staff meeting to plan and discuss Representative Areas Program (RAP) at Townsville offices

Restoration goals and planning. A primary aim of the Great Barrier Reef Marine Park Authority (GBRMPA) is to increase biodiversity protection, with the added intent of enabling the recovery of areas where impacts had occurred. A strong foundation for this has been achieved through the Representative Areas Program, by developing a representative and comprehensive network of highly protected no-take areas, ensuring they included representative examples of all different habitat types.

The rezoning also provided an opportunity to revise all the zone types to more effectively protect the range of biodiversity.

A further aim was to maximise the benefits and minimise the negative impacts of rezoning on the existing Marine Park users.

These aims were achieved through a comprehensive program of scientific input, community involvement and innovation.

More information on the extensive consultation process is available at http://www.gbrmpa.gov.au.

6. green and yellow zone examples

An example of Green Zones (marine national park) and Yellow Zones  (conservation park)

Monitoring. An independent scientific steering committee with expertise in Great Barrier Reef ecosystems and biophysical processes was convened to define operational principles to guide the development of a comprehensive, adequate and representative network of no-take areas in the Marine Park (Fernandes et al 2005). Science (both biophysical and social science) provided the best available information as a fundamental underpinning for the Representatives Areas Program.

There are currently over 90 monitoring programs operating in the Great Barrier Reef World Heritage Area and adjacent catchment. These programs have largely been designed to address and report on specific issues, location or management.

Reef management. GBRMPA’s 25-year management plan outlines a mix of on-ground work, policies, strategies and engagement. The actions include:

  • increasing compliance focus to ensure zoning rules are followed
  • controlling Crown-of-thorns Starfish (Acanthaster planci) outbreaks
  • ensuring cumulative impacts are considered when assessing development proposals
  • setting clear targets for action and measuring our success
  • monitoring the health of the ecosystem on a Reef-wide scale
  • implementing a Reef Recovery program to restore sites of high environmental value in regional areas — regional action recognises the variability of the Reef over such a large area and the variability of the issues and interests of communities and industries in each area.

Benefits of zoning to date. The benefits reef ecosystem health are already occurring including:

  • More and bigger fish: Larger fish are important to population recovery as they contribute more larvae than smaller fish. James Cook University research shows the network of no-take marine reserves benefits species of coral reef fish targeted by fishers (especially Coral Trout), with not only more fish, but bigger fish in reserves — some zones have around twice as much fish biomass compared to zones open to fishing.
  • Improved fish recruitment: Research in the Keppel Islands suggests increased reproduction by the more abundant, bigger fish in reserves. This not only benefits populations within those reserves, it also produces a ‘spill over’ when larvae are carried by currents to other reefs, including areas open to fishing.
  • Improved resilience: The spillover effects also mean the connectivity between reserve reefs is intact. Spatial analysis shows most reserve reefs are within the dispersal range of other reserve reefs, so they are able to function as a network.
  • Sharks, dugongs and turtles: These species are harder to protect because they are slow growing and slow breeding. They are also highly mobile, moving in and out of protected zones. Despite this, available evidence shows zoning is benefiting these species.
  • Reduced crown-of-thorns starfish outbreaks: Outbreaks of crown-of-thorns starfish appear to be less frequent on reserve reefs than fished reefs. This is particularly important as Crown-of-thorns Starfish have been the greatest cause of coral mortality on the Reef in recent decades.
  • Zoning benefits for seabed habitats: Zoning has improved protection of seabed habitats, with at least 20 per cent of all non-reefal habitat types protected from trawling.

How the project has influenced other projects. In November 2004, the Queensland Government mirrored the new zoning in most of the adjoining waters under its control. As a result, there is complementary zoning in the Queensland and Australian Government managed waters within the Great Barrier Reef World Heritage Area.

The approach taken in the Representative Area Program is recognised as one of the most comprehensive and innovative global advances in the systematic protection and recovery of marine biodiversity and marine conservation in recent decades and has gained widespread national international, and local acknowledgement of the process and outcome as best practice, influencing many other marine conservation efforts.

Stakeholders. As a statutory authority within the Australian Government, the Great Barrier Reef Marine Park Authority is responsible for managing the Marine Park. However, as a World Heritage Area, management of the ecosystem is complex jurisdictionally.

Both the Australian and Queensland governments are involved in managing the waters and islands within the outer boundaries through a range of agencies. GBRMPA works collaboratively with the Queensland Parks and Wildlife Service through the joint Field Management Program to undertake day-to-day management of the Great Barrier Reef, including its 1050 islands, many of which are national parks. The program’s activities include surveying reefs and islands, dealing with environmental risks such as ghost nets and invasive pests, responding to incidents, maintaining visitor facilities, and upholding compliance with Marine Park legislation and the Zoning Plan.

A wide range of stakeholders have an interest in the Great Barrier Reef, including the community, Traditional Owners, a range of industries and government agencies, and researchers. The public, including the one million people who live in the adjacent catchment (around 20 per cent of Queensland’s population), benefit from economic activities. In recent years, the number of tourists carried by commercial operators to the Great Barrier Reef averaged around 1.6 to 2 million visitor days each year (GBRMPA data) with an estimate of an additional 4.9 million private visitors per annum.

Resourcing. The resourcing required for rezoning of the Great Barrier Reef over the five-year period of the RAP (1999–2003) was significant. It became a major activity for the agency for several years, requiring the re-allocation of resources particularly during the most intense periods of public participation. However, the costs of achieving greater protection for the Reef are readily justified when compared to the economic benefits that a healthy Great Barrier Reef generates every year (about AUD$5.6 billion per annum).

Further information: www.gbrmpa.gov.au

Contact: info@gbrmpa.gov.au

All images courtesy Great Barrier Reef Marine Park Authority

 

Constructed Saltmarshes in two urban sites, Kooroowall Reserve and Gough Whitlam Park, Sydney, Australia

By Mia Dalby-Ball

Key words: Wetland, Saltmarsh, Intertidal, Urban Ecology, Construction

Introduction: Coastal Saltmarsh is an intertidal ecosystem under threat and currently listed on both the state (New South Wales (NSW)) and Australia’s national list as an Endangered Ecological Community. Saltmarsh provides a variety of ecosystem services, including providing habitat for crabs which then release larvae during some high-tides. Crab larvae from saltmarshes have been found to be key food for small fish.

Over 80% of urban saltmarshes in NSW have been filled for a range of uses including playing fields, often after their use as rubbish dumps. With an increase in awareness of the value of these ecosystems, the restoration of saltmarsh in urban areas is occurring globally and locally. Here we describe two saltmarsh reconstruction projects at Kooroowall Reserve and Gough Whitlam Park, Sydney.

Aim of the works. In each example the aim was to create a functioning saltmarsh – that is a saltmarsh with appropriate tidal inundation, appropriate plant species and cover and invertebrate species (e.g. crabs, molluscs).

Works undertaken. In both cases works commenced with soil testing (soil type, pollutants, acid sulfate soils and depth to ground water) followed by the development of a detailed design.   Hydrology was observed from surrounding areas to identify location-specific elevations connected to nearby existing intertidal areas. Substrate was then excavated to the desired level, top-soil was put in place to provide appropriate nutrients, then planting carried out and/or natural regeneration encouraged.

Figure 1. Reconstructed saltmarsh at Kooroowall Reserve, 2015

Figure 1. Reconstructed saltmarsh at Kooroowall Reserve, 2015

Figure 2.  Gough Whitlam Park January 2015 in 2m tide. (Photo M. Dalby-Ball)

Figure 2. Gough Whitlam Park January 2015 in 2m tide. (Photo M. Dalby-Ball)

Results to date. Around 80% cover of saltmarsh plant species has established and persists at both sites to date. (Figs 1 and 2.) Non-saltmarsh plants dominate the upper 5m of the Gough Whitlam Park as this was not excavated low enough, with a similar area occurring at the Kooroowall Reserve saltmarsh (Fig 3). Saltmarsh crabs and gastropods are present at both sites. Density of saltmarsh plants at both sites is greatest where the tidal inundation is most frequent. The before and after images show the dramatic change from a weed dominated, neglected area of fill (Kooroowall reserve) to Saltmarsh and from Turf (GWP) to Saltmarsh.

Natural regeneration and establishment of saltmarsh plants was highest where there was “wrack” covering the exposed sandy substrate. (Wrack is organic material such as washed up sea-grass or a mix of leaves fine twigs.) That is, saltmarsh seedlings that germinated in areas without wrack were found to die during consecutive hot dry days while those in wrack generally survived.

Figure 3. Kooroowall Saltmarsh January 2015. (Photo: M. Dalby-Ball)

Figure 3. Kooroowall Saltmarsh January 2015. (Photo: M. Dalby-Ball)

Lessons learned. Lessons include the importance of achieving the required tidal inundation. In both examples the level of some sections of the sites could have been lowered at the time of construction. In the case of Kooroowall an area of heavy clay was encountered and additional resources would have been required to implement the planned works. As the resources were not available, this was not done. The higher area now has Coastal Wattle growing on it, shading out the saltmarsh. There is now either a reoccurring cost to remove this plant, or if nothing is done, that area becomes terrestrial vegetation.

Fencing was found to be essential at the Kooroowall Saltmarsh as its proximity to a children’s play area resulted in it becoming a de facto bike jump area. No fencing was required at Gough Whitlam Park; however there is a high level of community engagement and interpretive signage.

It is likely that the wrack was beneficial in retaining moisture to assist survival of species.

Acknowledgements: Both Saltmarsh creation projects were facilitated and managed through local government. Kooroowall by Pittwater Council and Gough Whitlam Park by Canterbury Council. Both projects had grant funding (over 50%) from federal government sources distributed through the then Catchment Management Authorities. These agencies have now changed name to Local Land Services. Dragonfly Environmental designed the Saltmarsh re-creation and Gough Whitlam Park.

Contact: Mia Dalby-Ball, Director, Ecological Consultants Australia, 30 Palmgrove Road Avalon Beach Sydney NSW, 2107, Tel: +61 488 481 929, Email: ecologicalca@outlook.com

Acknowledgement. This is summarised from a talk first presented to the symposium ‘Rebuilding Ecosystems: What are the Principles?’ Teachers’ Federation Conference Centre, November 13th, 2014, Australian Association of Bush Regenerators (AABR).

Seagrass meadow restoration trial using transplants – Cockburn Sound, Western Australia

Jennifer Verduin and Elizabeth Sinclair

Keywords: marine restoration, seagrass, Posidonia australis, transplant, genetic diversity, microsatellite DNA, provenance

Cockburn Sound is a natural embayment approximately 16 km long and 7 km wide, to the west of the southern end of the Perth metropolitan area. Its seagrass meadows have been reduced in area by 77% since 1967, largely due to the effects of eutrophication, industrial development and sand mining. To answer a range of questions relevant to seagrass restoration, we (i) carried out a transplant trial, (ii) monitored the impact and recovery of the donor site, and (iii) retrospectively assessed genetic diversity in the transplant site.

Methods. (i) The transplant trial was conducted between 2004 and 2008 in an area totalling 3.2 hectares of bare sand at 2.2–4.0 m depth on Southern Flats, Cockburn Sound. Donor material was sourced from a naturally occurring seagrass meadow on Parmelia Bank, north of Cockburn Sound, approximately 16 km away from the transplant site. Sprigs (15–20 cm length) of a dominant local seagrass, Posidonia australis Hook.f., were harvested from donor material and each sprig tied to a purpose-designed degradable wire staples (30 cm in length) and planted and secured into a bare sandy area at 50 cm shoot spacing by SCUBA divers (Figure 1). Sprig survival was periodically monitored in 10 m x 10 m representative sub-plots (15–20 plots per hectare).

(ii) For the meadow recovery study, several plug (a clump of seagrass excavated) extraction configurations were examined in P. australis meadows to monitor shoot growth into plug scars, with metal rings placed into the resulting bare area to monitor shoot growth into it at 3, 10, 13 and 24 months. Rings of 8.3 cm diameter were placed into adjacent undisturbed meadows to act as reference plots. (iii) Shoot material was collected from established plants for microsatellite DNA genotyping from the donor site in 2004, and from the 2007/2008 plantings in the restoration site in January 2012. Genetic sampling from the restoration site was done from mature shoots only, to ensure we were sampling original donor material. DNA was extracted from shoot meristem and genotyped using seven polymorphic microsatellite DNA markers (Sinclair et al. 2009).

Fig1

Figure 1. Transplants in situ, prior to the pegs being covering with sediment (Photo Jennifer Verduin)

Results. (i) The transplants have grown well to fill in gaps and become a healthy, self-sustaining meadow, with first flowering in July 2010, three years after initial transplant in 2007. There has also been considerable natural recruitment in the area through regrowth from matte and new seedlings (Figure 2). (ii) No significant differences in shoot growth between extraction configurations were observed in the donor meadow, and there was an increase in shoot numbers over two years. Based on the number of growing shoots, the predicted recovery time of a meadow is estimated at three years. (iii) Genetic diversity was very high in the restored meadow (clonal diversity R = 0.96), nearly identical to the donor meadow.

Fig2

Figure 2. Aerial view of the restoration site (within yellow markers), with natural recruitment occurring from vegetative regrowth and new seedling recruits (Photo Jennifer Verduin, 2010).

Important considerations for long-term success and monitoring. While several important questions have arisen from this trial, it demonstrated that (i) the transplants achieved a high level of establishment within a few years; (ii) the high genetic diversity in the donor site was captured and retained in the restored meadow; and (iii) surrounding sandy substrate is being colonised by P. australis through regrowth from the matte and natural recruitment from seeds dispersed within and/or from other meadows, (the latter potentially helping to ensure the long-term viability of restored seagrass meadows.)

Partners and Investors: This project was carried out as part of the Seagrass Research and Rehabilitation Program through Oceanica Consulting Pty Ltd, with Industry Partners Cockburn Cement, Department of Commerce (formerly Department of Industry and Resources), WA, Department of Environment and Conservation WA, The University of Western Australia, and the Botanic Gardens and Parks Authority, WA.

Contact: Jennifer Verduin, School of Environmental Science, Murdoch University, Murdoch, WA 6150 Australia Email: J.Verduin@murdoch.edu.au; Elizabeth Sinclair, School of Plant Biology, University of Western Australia, Crawley, WA 6907 Australia Email: elizabeth.sinclair@uwa.edu.au. If you are interested in becoming involved with seagrass rehabilitation through student projects please contact us.

 

 

Fingal Headland Maritime Themeda Grassland Restoration

Keywords: Grassland, Themeda Grasslands on Sea-cliffs and Headlands, headland ecosystems, bush regeneration, Fingal Head Coastcare, Plectranthus cremnus

Kieran Kinney

Fingal Head, whose first inhabitants are members of the Cudginburra Clan, is a famous beauty spot in the far north coast of NSW, heavily utilised for recreation such as fishing, surfing, whale and dolphin watching and family outings. It is estimated that upwards of 50,000 visitors per annum use the site. As a result of this and other impacts including unfettered goat grazing (commencing around the lighthouse in the late 19th century), the site has many management challenges, including extensive gully and rill erosion, trampling of native vegetation, wildflower harvesting and weed invasion.

Prior to treatment, the ground cover layer was almost completely dominated by a form of the exotic Buffalo Grass (Stenotaphrum secundatum) and a suite of other weeds including Bitou Bush (Chrysanthemoides monilifera ssp rotundata). Because similar headlands in the region (Norries Head and Hastings Point Headland) support the State-listed  Endangered Ecological Community Themeda Grasslands on Sea-cliffs and Headlands it is assumed that Kangaroo Grass (Themeda triandra) was native to the site and became locally extinct due to the history of grazing and weed invasion.

Project works: In 2009 Fingal Head Coastcare determined that work to address the serious weed problems should commence and that trials be undertaken to reintroduce Kangaroo Grass.  Several small plots (100m² ea.) were sprayed with herbicide and slashed (Fig 1). Regenerating weed was regularly removed.

Fig 1: Trial plot 1 –  Natural regeneration within patch of treated Buffalo Grass

The plots were sown with Kangaroo Grass seed collected from other headlands in the region. The material used is a genetically distinct coastal form of Kangaroo Grass that exhibits a unique decumbent growth habit. Ripe fruiting culms were distributed in quadrats as well as randomly over the plots.

In addition to the Kangaroo Grass trials, efforts were made to plant a variety of typical Grass and Forbland species, including Golden Everlasting Daisy (Xerochrysum bracteatum), Evolvulus alsinoides and Chamaechrista maritima. These were propagated in the Fingal Coastcare nursery from seed and stock sourced at nearby headlands.

Results. Regeneration of native species  was extensive across the plots (Figures 2a and 2b). Regenerating native species included Prickly Couch (Zoyzia macrantha), Native Violet (Viola banksii), Angled Lobelia (Lobelia alata) Plectranthus (Plectranthus cremnus) and Beach Bean (Canavalea rosea).

Fig 2a: Typical Buffalo Grass infestation prior to commencement of trials.

Fig 2b: Example of regeneration of native grasses Prickly Couch and Blady Grass after works (Plot 1, 2011).

Both the Kangaroo Grass  and the Everlasting Daisy (Figure 3) have since naturalised on the site. However, the plots revealed very poor rates of germination of Kangaroo Grass, approximately 1 in1000. Germination rates were much higher under controlled nursery conditions

Fig 3: Everlasting Daisy re-established and recruiting on Fingal Headland.

Outcomes and lessons learned The low rate of Kangaroo Grass germination is not regarded as a major impediment to the overall success of the project. As natural processes and cycles come into play, it is probable that Kangaroo Grass will become a significant part of the biota on the headland. That is,  achieving the ultimate aim of a Closed Tussock Themeda Grassland is probably unlikely through reintroduction from the seed sowing methods we used, but may occur naturally over time.

The extensive natural regeneration of the threatened Plectranthus cremnus is a major success of the trials.  This herb species is habitat for a local population of Blue-tongue Lizards and Bearded Dragons. It is a major food source for the reptiles, supplementing their animal diet, which may be very seasonal.

Erosion control has been significantly reduced through active intervention, using hard infrastructure in combination with ‘low key’, passive techniques such as strategic plantings and bush debris.

Local school children are involved in the plantings on an ongoing basis, and have picked up vital local knowledge and site ownership along the way. This project has been a major education experience for the Coastcare group, the Tweed Byron local Aboriginal Land Council and many members of the Fingal Head Community who were previously not aware of this Endangered Ecological Community . The trial areas are now a profusion of wildflowers almost the year round and the Coastcare volunteers receive many compliments from the passing public. During working bees on the site considerable energy is devoted to educating the public about the Grasslands in the hope that this will assist in their protection (and also because it is a lot of fun!)  Anyone who visits the site will be captivated by the delicate beauty of the native flora, the awesome scale of the natural scenery and will surely agree that something special is happening here.

Where to from here?: One of the most challenging and pressing issues facing the headland is uncontrolled pedestrian traffic. Although this may be unavoidable to some extent, it is desirable for the long term health of the ecosystem that some control methods be introduced to the site. Trials have been conducted using bush debris with limited success. More permanent methods would have to be carefully designed and implemented in order to blend with the unique aesthetics of the site. Boardwalk construction has been very successful in key areas, however this type of construction is deemed inappropriate for the grassland proper.  Dense vegetative barriers consisting of tussock forming species such as Spiny Mat Rush (Lomandra longifolia) and Knobbly Club Rush (Isolepis nodosa) are being planted to rationalise the trackways and guide pedestrians away from more sensitive areas.

In terms of the vegetation restoration works, ongoing and extensive follow-up weed control is required and it is envisaged that as each plot is stabilised and achieves manageable levels of autonomy, new areas will be opened up for weed control. It is recommended that a formal Restoration Plan be developed and implemented, perhaps through funding avenues or the involvement of Environmental Science students. This would greatly assist guiding the works over an extended period and help achieve the best possible outcomes for Fingal Headland and the wider community.

Partners and Investors: Fingal Head Coastcare Inc. consulted with the Tweed Shire Council, The Tweed Byron Local Aboriginal Land Council and a number of community groups to plan this project. The community groups include the Fingal Heads Community Association, the Fingal Head Public School, Fingal Rovers SLSC, local businesses and other Tweed Coast Dune care groups.

Contact : Kieran Kinney,  Fingal Head Coastcare Project Manager, 28 Kurrajong Ave Cabarita Beach 2488. Tel:  +61 266763002 Mob: 0457356175.   Email : kierankinney@gmail.com

Kirra Dune Revegetation – Queensland.

Key words.  Dune reconstruction, strand ecosystem,

Mark Bibby

A project was developed in 2009 to remove sand from the intertidal area at Kirra to form a new series of dunes along a 1.5km stretch of beach from Kirra to Bilinga, on the far south coast of Queensland (Fig 1).  While the purpose was to maintain the beach amenity and reinforce a buffer to the shoreline, the reconstruction of the dunes (to an average height of 4 metres and the width v from 25 to 60 metres) also involved reinstating native plant communities along the dunes for stabilisation and the conservation of biodiversity.

Fig 1: Project area – 1.5km stretch of beach from Kirra to Bilinga, Queensland.

Revegetation was conducted in the frontal dune area of the project site and in strategically placed infill planting cells between the frontal dune and the existing vegetation landward edge of the project site (Fig 2). Four locally occurring dune species were selected: Spinifex (Spinifex hirsutus) 65%; Beach Bean (Canavalia rosea) 5%; Goats Foot Convolvulus (Ipomoea pes-caprae) 15%; and Vigna (Vigna marina) 15%.

Fig 2: Revegetation of the dune system using infill planting cells and four locally occurring plant species (April 2011).

For a 12 week period the plants were monitored and watered with a 25,000L capacity off-road truck, with plants replaced as required. The site was then maintained for a period of twelve months post-planting to promote good growth of installed plants, prevent weed incursion, ensure dune stability through increased native vegetation cover and assist natural regeneration of dune species.

The total length of the planting area is 1515m and  approximately 18,000 tubestock were planted out over an area of 18000m2 by a team of 6, who planted a total average of 4500 plants per day.

Results. Planting survival rates varied mainly due to mobile sand and anthropogenic disturbance. Good rainfall over the installation period and for 4 weeks following planting ensured establishment was successful (Fig 3).

Fig 3: Revegetation of dune system 5 months after works (Sept 2011)

At 12 months after the planting on the foredune, Beach Spinifex (Spinifex sericeus) densities are approaching, or in some areas have reached, densities expected for a naturally established frontal dune (Fig 4). Since planting, the nursery-spelled Beach Spinifex have flowered and seeded, however the bulk of the increase in biomass is due to extension of the runners. Beach Spinifex runners have travelled in all directions across the dune (i.e. including up inclines). Small swales of windswept sand can be seen captured in front of Beach Spinifex. Of the three species planted on the frontal dune, Beach Spinifex (overall) has shown the greatest increase in area covered.

Fig 4: Revegetation of dune system 12 months after works (April 2012).

The other two species Vigna (Vigna marina) and Beach Morning Glory (Ipomoea pes-caprae) have also done well, although not increased their biomass as rapidly as the Spinifex. The plants, however, have had a good survival rate and throughout December to April 2012 have seen an increase in their rate of growth. Based on the slower (compared to the Spinifex) growth rates that both the Vigna and the Beach Morning Glory exhibited throughout the establishment period either:

(a) they naturally require more time to establish;

(b) their growth rate throughout winter months is less than Spinifex;

(c) they are more sensitive to wind-blown sand than the Spinifex; or

(d) a combination of factors.

Growth rate, however, was not a specific metric that influenced the decision to include these species in the revegetation species selection; the primary reason for their inclusion was to increase in situ species richness in the mid- to long term. Based on this, their inclusion has been successful. As mentioned previously they are now growing more rapidly and both species have flowered and produced seed.

Runners are beginning to connect the infill planting cells with the frontal dune row plantings. In addition to the three species used in the frontal dune plantings, Beach Bean (Canavalia rosea) was also included. The establishment, growth and survivorship of Beach Bean has been similar to that of Vigna — a period where growth appeared minimal and then more rapid growth throughout summer 2011/2012.

Overall survival rate is approximately 80%, however survival rate of individual plants is probably not the best measure of success for a project of this nature. Percentage cover or biomass is a more appropriate measure. Despite this, whichever measure of success is chosen the project has met and exceeded requirements.

Plant abundance and vegetative cover are very good to excellent. Combined with the species composition (richness) many areas of the frontal dune are indistinguishable from a naturally occurring frontal dune. The plants are reproducing and increasing their abundance; at this point predominantly vegetatively (i.e. ‘runners’) however all species have produced seed and these could reasonably be expected to add to the plant population.

The plants are well established and (in the absence of any extreme natural events or destruction by intent) self-sustaining.

Lessons learned.  Beach Spinifex (Spinifex sericeus) is a rapid colonizer of frontal dunes and was the first of the four planted species to reinforce a buffer for the newly created dunes.

The largest threats against successful establishment are:

  • Anthropogenic disturbance through the planting establishment area. This resulted in breaking the ‘crust’ that forms on the top of semi-stable sand, making the underlying sand more susceptible to erosion.
  • Sandblow that covers or undermines plants in the first few months post planting.

Because the sand was “sterile” (due to it having been reclaimed from the intertidal zone and lacking a seed bank), weed invasion, up to this point, has been minimal. This may suggest that weeds predominantly recolonise natural dunes due to accumulated seeds and other propagules persistent in the sand.

Stakeholders: The Department of Environment and Resource Management (DERM) has been responsible for the project management of the Kirra Beach Restoration Project. The Gold Coast City Council (GCCC) is a key stakeholder and the primary service provider for the works.

Contact: Mark Bibby, Gecko Regen, / 139 Duringan Street,Currumbin, Qld, Australia. Tel:  +61 (7) 5534 6395. Email: admin@geckoregen.org.au ; http://www.geckoregen.org.au/