Category Archives: Coastal & marine

The ecological restoration of Te Motu Tapu a Taikehu, Hauraki Gulf, New Zealand

The Motutapu Restoration Trust 

Introduction. Te Motu Tapu a Taikehu (Motutapu Island, 1509 ha) is located in the Hauraki Gulf Marine Park, situated on the east coast of the north of New  Zealand’s North Island. It lies immediately adjacent to Rangitoto Island which is a volcano that last erupted approximately 500-550 years ago. This, and previous eruptions would have regularly devastated the forest and wetland ecosystems on Motutapu.

After a history of Maori settlement, European clearing and farming and use for military purposes during WWII, the Island was transferred to what is now the Department of Conservation (DOC) in 1970. The island is now designated a recreation reserve, open to the public.

Pollen records suggest that after the Rangitoto eruptions ceased around AD 1500, Motutapu recovered to be covered by a patchwork of lowland podocarp/broadleaf forest typical of that found in the Auckland region, and presumably was habitat to birds, reptiles, bats, fish and invertebrates similar to those on other Northland islands and the mainland.

Habitat loss through anthropogenic disturbances including fire, clearing for farming, and the introduction of mammalian predators saw many species of native bird, reptile and plants extirpated. Prior to restoration started in 1994, Motutapu was almost entirely covered by pastoral grassland dominated by exotic species, except for a few, very small forest remnants, and a depauperate native faunal communities.

Motutapu Island is a 40-minute ferry journey from Auckland City. Map: Department of Conservation

Restoration project

Planning of the ecological restoration program is undertaken by the Natural Heritage Committee of the Trust, a group of some 15 volunteers who meet monthly to plan, and discuss implementation. Members are highly qualified, skilled and enthusiastic practitioners. Together the committee  brings sound ecological theory and practice to the  restoration of flora and fauna. Published plans they work from include the 1994 Motutapu Restoration Working Plan and subsequent 2010 audit.

The objective is to return the island forest and wetland ecosystems to a post-eruption state, with a goal of reaching 500 ha of restored forest and wetland over coming decades. Although this area is far less than the full area of the island, it allows the conservation of cultural and archaeological sites, such as pā, WWII infrastructure, and farming landscapes. The post-eruption state can be described as lowland mixed broadleaf/podocarp forest, with a suite of seabirds, waders, forest birds, reptiles, bats and invertebrates interacting with each other so that natural evolutionary processes can once more resume for these taxa on the island.

Implementation of the ecological restoration of Motutapu has been underway for 23 years, since the formation of the Motutapu Restoration Trust (MRT) in 1994. To date,  in excess of 100 ha of pasture has been converted  to pioneer forest representing an estimated 450,000+ trees  planted. Volunteer hours total 21,462 between  2005 and 2015, and is currently in excess of 3,200 hours annually.

The major activities of the ecological restoration are:

  • Seed collecting from the island and wider Auckland region
  • Plant propagation in the island nursery – year round
  • Planting in the winter months
  • Weeding year round
  • Fauna translocation and monitoring (birds, reptiles, fish and crustacea) in conjunction with DOC

Planters in action: Photo: MRT

15,136 plants went into Hospital B paddock; one of the most difficult planting sites on the island.
Photo: MRT

Home Bay forest, with Motuihe Island and the Auckland mainland in the background. Photo: MRT

Revegetation. The original strategy (1994 – 2009) was to initiate successional processes by planting pioneer phase species, which would later give way to mature phase species dispersed naturally by birds. However, it was realized that mature phase species would be slow to arrive, as the island is isolated from native forests on nearby islands and seed dispersal from them is unlikely. If seed is dispersed from its own remnant forests, any new forest will continue to reflect the depauperate nature of these remnants.

In 2010, the planting strategy was updated to include enrichment planting of mature phase forest species into the forests planted up to 15 years earlier. Seeds for this were eco-sourced from the wider Auckland region, within boundaries agreed with DOC, and brought to the island nursery for propagation. This was an opportunity to return species to the island that are currently absent, including Swamp Maire (Syzygium maire), Tree  Fuchsia (Fuchsia excorticata),  Pigeonwood (Hedycarya  arborea), White Maire (Nestegis lanceolata), Black Maire (N. cunninghamii), Turepo (Streblus  banksii) and a number  of podocarps including Matai (Prumnopitys taxifolia), Miro (P. ferruginea) and Rimu (Dacrydium cupressinum).

The project has a large nursery, operated by one full time volunteer and supported by other volunteers during the week and weekends. The nursery provides all the plants for the planting programme. Seed is collected by a small team of collectors who travel Auckland’s and the Island’s forest remnants for seeds all year round. Growing media is supplied pro bono by Daltons and Living Earth and delivered by DOC boat. The risk of importing the introduced pests Rainbow Skink (Lampropholis delicata) as eggs and Argentine Ant (Linepithema humile) precludes bringing potted plants onto the island.

Weeds such as Woolly Nightshade (Solanum mauritianum),  Moth  Vine (Araujia  sericifera), Evergreen  Buckthorn (Rhamnus alaternus), Apple of Sodom (Solanum linnaeanum), pampas (Cortaderia  spp.), and Boneseed (Chrysanthemoides monilifera) have been  present on the  island for many years, and in pasture had been kept in check by grazing. However, when pasture is retired, populations of these weeds  explode and threaten the plantings on not only Motutapu  Island, but also by dispersal to neighbouring Hauraki Gulf Islands. In particular, Rangitoto Island is threatened by invasion of weeds from Motutapu.

Weeding of the planted forests takes place in a strategic and planned way year round. Volunteers routinely grid search the plantations and control the infestations (using the hip chain method). Sources of reinfestation on other parts of the island are addressed by contractors who have the training to get at inaccessible weeds (e.g., cliff faces). New drone technology is in the process of being recruited to  identify infestations of weeds  from the  air, where they cannot be seen from the ground, or where access is particularly hazardous (e.g., cliff faces).

Pest species management. The suite of mammalian predators and herbivores on the Island prior to 2009 were detrimental to both flora and fauna, and their continued presence would have meant that neither locally extinct bird and plant species could be reintroduced, nor palatable plant species thrive.  These pests included: rats (Rattus rattus,  R. norvegicus, R. exulans); House Mouse (Mus musculus); Stoat (Mustela erminea); feral Cat (Felis catus); Hedgehog  (Erinaceus  europaeus occidentalis) and the European Rabbit (Oryctolagus cuniculus).

The successful eradication of pests from Motutapu and Rangitoto Islands was undertaken by DOC in 2009 using helicopters to disperse broadifacoum. DOC employs a biosecurity ranger on the island who responds to any new rat, stoat or other incursions.

Recent arrivals of North Island brown kiwi bring the total to 26, closer to the target of 40 required for a founder population. Photo: MRT

Further releases of takahē will bring the breeding
pairs to a total of 20, the largest total outside Fiordland. Photo: MRT

Faunal translocations. A major milestone was the declaration in 2011 of pest-free status for the Island, and the subsequent re-introductions of birds and aquatic taxa that this allowed.

The island’s pest-free status gives safe refuge to some of New Zealand’s rarest bird species. Since it became pest-free, the following rare, endangered and non-threatened species have been translocated:

  • Coromandel Brown Kiwi (Apteryx mantelli)
  • Takahē (Porphyrio hochstetteri)
  • Tīeke (Philesturnus rufusater)
  • Shore Plover (Thinornis  novaeseelandiae)
  • Whitehead (Mohoua albicilla)
  • Pāteke (Anas chlorotis)
  • Redfin bully (Gobiomorphus huttoni)
  • Koura (Paranephrops planifrons)

Survey and Monitoring.  Annual surveys of terrestrial birds and shorebirds by the Ornithological Society of New Zealand have been undertaken since 2007. As well,  a survey of seabirds nesting on the island is underway, and monitoring of translocated birds by MRT volunteers in association with DOC is ongoing. Stream fauna and reptiles are surveyed and reported on annually by DOC.

The Island’s native and exotic plants are also being surveyed to ascertain progress of the recovery over time, and plant survival rates have been monitored informally via regular tours of the plantings to assess what is working and what is not.

Evidence that recovery processes are securely occurring on the island

It is clear that the 100ha of restored vegetation has resulted in natural processes of vegetation recovery occurring, with natural regeneration evident for many species. Once the fruiting forest is fully established on Motutapu Island we envisage that it will be fully self-sustaining via seed dispersal by frugivorous birds.

Populations of fauna, with four exceptions, appear to be self-sustainable on Island. Many of the reintroduced bird species are clearly reproducing on the island and populations are growing without human intervention as evidenced by our bird surveys. The exceptions are Shore plover and Pāteke which naturally disperse away from the Island, necessitating several translocations to ensure the populations build to create a resident population, and are viable. Kiwi and Takahē populations are still being built up to founder population size.

 Bird species (terrestrial diurnal including waders):

  • an increase from 50 species in 2010 to 60 in 2015
  • Re-introduced populations expanding: Takahē, Whitehead,  Tīeke
  • Self-introduced or now detectable: Kākāriki (Cyanoramphus novaezelandiae), Bellbird (Anthornis melanura), Spotless Crake (Porzana tabuensis), Little Blue Penguin (Eudyptula minor), Banded Rail (Gallirallus phillipensis), Grey-faced Storm Petrel (Pterodroma macroptera  gouldi).

Reptiles: Population and range expansions of the four native and one introduced species. The following are the natives:

  • Common Gecko (Woodworthia maculatus): up to ten-fold at some sites since 2008
  • Suter’s Skink (Oligosoma suteri): up to a hundred-fold at some sites since 2008 baseline
  • Copper Skink (Cyclodina aeneum): up to ten-fold at some sites since 2008 baseline
  • Moko Skink (Oligosoma moco): up to ten-fold at some sites since 2008

Fish:

  • Giant kokopu (Galaxius argenteus) now

Secure engagement with local  stakeholders.

There are a number of stakeholders that are fully engaged in the project through the MRT,  including:

  • Department of Conservation – MRT’s partner since the inception of the Trust in 1994, which has been responsible for some of our biggest milestones, such as the eradication of mammalian predators 2009-2011.
  • Motutapu Farms Ltd – leases the pasture from DOC to farm beef and sheep, becoming Auckland’s largest Another long-standing partner, helping the ecology of the island and wider Hauraki Gulf by farming organically.
  • Ngāi Tai ki Tamaki – the iwi who have mana whenua on the island and give their blessing to reintroduced fauna
  • Ngāti Paoa & Ngāti Tamaterā – Coromandel iwi who are kaitiaki of the North Island Brown Kiwi (Coromandel  subspecies) on
  • Motutapu Outdoor Education Centre (MOEC)  – use the island for accommodation of school groups gaining outdoor
  • Pāteke recovery
  • Takahē recovery group
  • Auckland Zoo – monitoring the populations of Redfin Bully ( Gobiomorphus huttoni) and Koura (Paranephrops planifrons).

Contact : Liz Brooks, Manager, Motutapu Restoration Trust, Newmarket, Auckland 1149, New Zealand.  Tel: +64 9 455 9634; PO Box 99 827; Email:  liz@motutapu.org.nz

 

Motuora Restoration Project, New Zealand

Key Words: Ecological restoration, reintroductions, island restoration, community engagement, Motuora Restoration Society

Motuora Restoration Society (http://motuora.org.nz) is recognised by the New Zealand Department of Conservation as the lead community agency for the restoration of Motuora, an 80 ha island in the Hauraki Gulf, New Zealand.  Since 2003 the Society has taken responsibility for the Island’s day-to-day management as well as developing and implementing the Island’s long term restoration strategy. Our aspiration is summed up in our  statement “It is our dream that future generations will enjoy a forest alive with native birds, reptiles and insects”.

Figure 1 – Aerial view of the Island before planting began. Area to bottom left has been sprayed in preparation for planting (Photo from cover of 2007 Motuora Native Species Restoration Plan).

Figure 1 – Aerial view of the Island before planting began. Area to bottom left has been sprayed in preparation for planting (Photo from cover of 2007 Motuora Native Species Restoration Plan).

 Figure 2 – Aerial view of the Island after completion of the pioneer planting. (Photo by Toby Shanley)


Figure 2 – Aerial view of the Island after completion of the pioneer planting. (Photo by Toby Shanley)

Background. Motuora is located on the east coast of New Zealand’s North Island near Auckland City. Motuora would once have been tree-covered and have hosted a wide range of native plants, invertebrates, reptiles and birds, particularly burrow-nesting seabirds. It was visited by early Polynesian settlers, later Māori, who would have initially camped, but later lived more permanently on the Island raising crops and harvesting fish, shellfish and presumably seabird eggs, chicks and adults. European settlers later occupied the Island, burning off most of the bush to encourage growth of grasses for their grazing livestock.

Towards the end of the farming period in the 1980s most of the Island’s native flora and fauna were gone. Interestingly however, there were never breeding populations of introduced mammalian pests on the Island so the remnant ecosystem had not been impacted by mice, rats, mustelids, hedgehogs, possums, goats, pigs or deer.

From about 1987 onwards both Government and members of the public began to take an interest in the Island and to promote the idea of adopting it as a predator-free bird habitat. Discussions continued over the next few years and by 1992 a sub-committee of the mid-North Royal Forest and Bird Protection Society had been formed and, in partnership with the Department of Conservation, drew up the first ‘strategy plan’ for the Island. Work parties began seed collecting, trial tree planting, weeding and fencing upgrades. By 1995 it had become apparent that the project could best proceed by way of an independent group dedicated to the task and the Motuora Restoration Society was formed.

The work on Motuora was designed to be a true restoration project combining firm ideas about the model ecosystem desired and a ‘bottom-up’ approach (vegetation-invertebrates-reptiles-birds) timing planting and introductions in a logical sequence. The historical presence of species on Motuora was inferred from comparisons with other less modified islands off the north east of the North Island, and particularly those from within the Rodney and Inner Gulf Ecological Districts, and using paleological information collected from the adjacent mainland.  Motuora Restoration Society has resisted the temptation to add iconic attractive species not originally present on the Island which might have raised the profile of the project.

Works carried out. The Society and its volunteers have contributed many thousands of hours to the restoration of the Island since 1995, raising and planting more than 300,000 native seedlings. This was particularly challenging with the logistics of working on an island without a regular ferry service or wharf. The project also included seabird and other species translocations, monitoring, weeding and track maintenance as well as fundraising.

The framework adopted began with reforestation so that appropriate habitat could be reinstated. A nursery was set up and seeds were collected from the Island, from nearby islands and, when necessary, from the mainland. With the exception of some areas of higher ground providing panoramic views from the Island, the land area was prepared (by weed-killing rampant kikuyu grass) and planted with hardy, wind and salt tolerant tree species. Once the trees were established, the canopy closed and sufficient shelter available, less hardy species and those requiring lower light levels were planted among the pioneers.  Today the planting of 400,000 trees of pioneer species is all but complete; and the raising and planting of ‘canopy’ and less hardy species continues.

In terms of fauna, invertebrate populations were surveyed and have been monitored as the forest has matured. One species, Wētāpunga (Deinacrida heteracantha) has been introduced.   Four reptiles have been introduced: Shore Skink (Oligosoma smithi), Duvaucel’s Gecko (Hoplodactylus duvaucelii),  Raukawa Gecko (Woodworthia maculata) and Pacific Gecko (Dactylocnemis pacificus).  One small land bird – Whitehead (Mohoua albicilla) has been translocated with 40 individuals moved to the Island.  Four seabird species have been attracted or translocated to the Island including the Common Diving Petrel (Pelecanoides urinatrix), and Pycroft’s Petrel (Pterodroma pycrofti).

Results. The project has restored Motuora from a pastoral farm (dominated by introduced grasses, weeds and only a small remnant fringe of naturally regenerating native forest) to a functioning native ecosystem, predominantly covered in early succession native forest with an intact canopy.

Initially the population of invertebrates was dominated by grassland species but the range and population size of forest dwellers has now much improved and the invertebrate fauna is now rich and plentiful (although rarer and endangered species are still to be added).  An initial suite of populations of flightless invertebrates remain depauperate.  Whitehead, an insectivorous bird species, has flourished with a current population of several hundred. At this early stage in the introduction of native fauna it is possible to report successful breeding and, for the most part, sufficient survival of initial colonisers of the species introduced to suggest that new populations will be established.  Sound attraction systems have led to initial breeding of Fluttering Shearwater (Puffinus gavia) and Australasian Gannet (Morus serrator).

Partnerships. Management of the Island is shared with the Department of Conservation (DOC) who administer the site on behalf of the Crown. DOC has legal commitments to engage with and act on behalf of the general public and particularly with iwi (Māori) who have generally expressed strong support for the restoration project and are expected to have co-management rights over the Island in the future.

Over the years the combined efforts of DOC staff, University researchers, the committee, thousands of volunteers and a host of donors and sponsors have worked hard to bring the Island to its present state.

Future directions. A sustained effort will continue to be required each year on biosecurity and weeding programmes. It will be many more decades before the forest matures and seabird and reptile populations reach capacity levels and a substantial workload is anticipated in managing and monitoring the emerging ecosystem for many years to come.

Acknowledgements: The success of the project is reinforced by the fact that the Society has maintained a close collaboration with a range of scientists and have inspired the active support and engagement of so many volunteers.  We thank all our inspiring volunteers and the following participating academics and researchers who have contributed to the project over the past ten years: Plants: Shelley Heiss Dunlop, Helen Lindsay (contractor). Reptiles: Marleen Baling (Massey University), Dylan van Winkel (consultant), Su Sinclair (Auckland Council), Manuela Barry (Massey University). Invertebrates: Chris Green (DOC), Robin Gardner-Gee (Auckland University), Jacqueline Beggs (Auckland University), Stephen Wallace (Auckland University). Birds: Robin Gardner-Gee (Auckland University), Jacqueline Beggs (Auckland University), Kevin Parker (Massey University), Richard Griffiths (DOC), Graeme Taylor (DOC), Helen Gummer (DOC contractor). The restoration project has been supported financially though grant aid received from a wide range of funders.

Contact: Secretary, Motuora Restoration Society, Email: secretary@motuora.org.nz; www: http://motuora.org.nz/

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.