Category Archives: Coastal & marine

Restoration of Wollongong’s Tom Thumb Lagoon 25 Years On: UPDATE of EMR feature.

 Nicholas Gill

[Update of EMR feature: Gill, Nicholas (2005) Slag, steel and swamp: Perceptions of restoration of an urban coastal saltmarsh. Ecological Management & Restoration, 6:2, 85-93 https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2005.00224.x]

Keywords. coastal wetlands, urban green space, pollution, mangroves, volunteers.

Figure 1. Tom Thumb Lagoon and Greenhouse Park (a) 2008 and (b) 2017. (Source Google Earth)

Introduction. The 2005 feature was drawn from restoration work my students and I became involved in during the early 2000s at Tom Thumb Lagoon (TTL) – an estuarine wetland close to Wollongong’s CBD and adjacent to the Port Kembla industrial area and harbour. By that point Wollongong City Council (WCC), the Bushcare group Friends of Tom Thumb Lagoon (FTTL), industry, Conservation Volunteers Australia (CVA), and many volunteers had been variously working on the site since the early 1990s. After decades of impacts from industrial development, waste disposal, and neglect, this significant restoration effort encompassed removing landfill, reshaping the wetland with channels and shallow benches, revegetation, weeding, and the construction of access and viewing points. By the time we became involved and I wrote the 2005 paper, TTL and the adjacent Greenhouse Park (GHP; Fig 1), were substantially revegetated, aesthetically improved, and the saltmarsh wetlands were seen as ecologically valuable. Participants and stakeholders in the restoration project perceived that substantial progress and improvement had been made. They also perceived, however, that the project suffered from some issues common to such endeavours such as a lack strategic planning and monitoring of ecological outcomes.

Since this time, restoration and other work has continued at TTL and at GHP. The story of what has happened, however, is one of the dynamic and contextual nature of sites such as this. This is true in a biophysical sense of ongoing vegetation change, particularly the spread of Grey Mangrove (Avicenna marina), a native plant previously not occurring on the site but planted for perceived environmental benefits either in the 1990s, or around 2000. This spread (into what was previously saltmarsh and mudflats) arises from past decisions and, while providing benefits, is now potentially causing new problems as well as continuing debates about choices in restoration.  The social context has also been dynamic and influential, as priorities have shifted, as the funding environment has altered, and as the people and groups involved have changed. Finally, Tom Thumb Lagoon remains affected by the legacy of the industrial history of its location. Past waste disposal practices in the absence of regulation have led to pollution problems that have become of greater concern since the early 2000s.

Activities at Tom Thumb Lagoon and Greenhouse Park Today. The wetland area itself is adjacent to a capped waste disposal site that operated from the 1940s until the mid-1970s. This area is known now as Greenhouse Park and is being managed and developed as urban green space with more focus on fostering urban sustainability practices; any restoration work is nested within these foci. TTL and GHP were always associated through overlap between FTTL and GHP staff, and GHP facilities were a base for TTL activities. Today, however, personnel have changed, FTTL no longer exists and its key members are no longer associated with TTL, and TTL/GHP are managed as one site to a greater extent. The result of these factors, and of the achievements already made at TTL, have been a shift towards an emphasis on activities at GHP and a change in TTL activities from active restoration to maintenance. It is now GHP volunteers and associated WCC staff who undertake and oversee work at TTL. At GHP WCC has expended considerable resources in tree planting and expanding a permaculture garden. There is a shelter, outdoor kitchen, and pizza oven for volunteers, WCC and Wollongong firms compost green and food waste, and there are hopes for public, tourism, and event use. Around ten volunteers work at the site weekly. For the GHP staff and volunteers, activities at TTL itself today are largely limited to weeding, picking up litter, and feral animal control. Weeds and litter remain problems, partly due to TTL’s location at the bottom of an urban catchment. In addition, since 2005, frog ponds were installed at the eastern end of TTL for the endangered Green and Golden Bell frog (Litoria aurea), however, it is not clear if the ponds are effective. The non-native Giant Reed (Arundo donax) also remains well established at this end of TTL despite control attempts.

Shifts in support have meant that CVA bowed out of work at TTL/GHP in 2012. Previously their involvement had been via a wetlands program that relied on support from both industry (including Bluescope and NSW Ports, both operating adjacent to TTL) and government programs. Until 2012, in conjunction with WCC, CVA were revegetating the southern slopes of GHP (marked A in Fig. 1) and were removing weeds and litter from the saltmarsh. However, the funding that CVA relied on declined such that CVA was unable to continue at TTL/GHP.

Figure 2.  Eastern end of TTL looking south (a) 2002 and (b) 2019 (Photos Nick Gill)

The Mangroves are Coming. Apart from further revegetation at GHP, the most significant vegetation change at TTL has been the spread of Grey Mangrove. While approval to thin this species has been obtained in the past and some thinning did occur, it has not mitigated their current spread and density. Grey Mangrove spread is clearly seen for the period from 2002 to 2019 in Fig 2 which shows the eastern end of TTL and the southern end of the channel known as Gurungaty Waterway. Aerial photos further reveal changes from 2008-2017 where the largely east-west spread of mangroves along channels in TTL can be seen (marked B in Fig 1). Significant spread can also be seen north-south spread along Gurungaty Waterway over this period (marked C in Fig 1). As the 2005 paper records, not long after Grey Mangrove was planted in the late 20th or early 21st Century, its expansion was  soon causing concern for its consequences for the site’s mudflats, saltmarsh and tidal habitats although it appears to have largely remained confined to the channels and has no doubt generated some environmental benefits. In terms of its consequences on bird habitat, the long observations of local birdwatchers suggest that the expansion of Grey Mangrove has reduced the incidence of waders and shorebirds, particularly Black Winged Stilts (Himantopus himantopus) and also waterfowl and herons. Nonetheless, observers report that Grey  Mangrove colonisation is providing habitat for other birds, such as the Sacred Kingfisher (Todiramphus sanctus), the Nankeen Night-Heron (Nycticorax caledonicus), and the Striated Heron (Butorides striata). Elsewhere across more upland areas of TTL and GHP, the expansion of tree planting across GHP and TTL has seen a shift to birds favouring woodland habitats.

The expansion of Grey Mangrove is also implicated in flood risk, especially for the catchment of Gurungaty Waterway. A 2019 review of the Wollongong City Flood Study, suggests that low elevations and channel infrastructure, combined with sedimentation and flow limitations associated with the now dense mangroves (Fig. 3), have increased the likelihood of flooding in the urban catchment.

Figure 3.  Southern Gurangaty Waterway in (a) 2002 and (b) 2019. Note the steel footbridge on left of each photo. (Photos Nick Gill)

Industrial Legacies. The 2005 paper notes that saltmarsh restoration was an important part of the TTL work and that stakeholders saw the saltmarsh as a significant ecological element of TTL. Since 2004 coastal saltmarsh has been listed as an Endangered Ecological Community in NSW. From 2006, saltmarsh degradation prompted WCC to monitor the saltmarsh and analyse groundwater and soils.  This showed that the degradation was likely associated with ammonia leaching from the tip and causing nitrate pollution, and also with a hydrophilic layer of iron hydroxide in the soil causing waterlogging and contaminant absorption. The possible origins of this layer include past waste disposal practices from metal manufacturing.

These, however, are not the only legacies of past unregulated waste disposal and industrial activity. TTL is now a declared site of ‘significantly contaminated land’ by the NSW EPA. The 2018 declaration notes that site is contaminated by ‘polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons and other mixed contaminants from multiple sources including coal tar and lubricant oils’. At TTL elements of these can be visible as a film on the water surface and are among the substances leaching from GHP. Such substances are carcinogenic and exposure can cause a range of health problems. The presence of these materials in the groundwater has been known since the 1990s but from 2013 WCC began to monitor and map these materials. Monitoring points were installed along the wetlands at base of the old tip. Various remediation options for these contaminants, as well as for the nitrates and iron hydroxide layer, were proposed but action was not taken at this time for various reasons including disruption to the wetland, costs, and uncertainties regarding pollutant interception. As of 2019, the site is subject to a ‘Voluntary Management Proposal’ by WCC which includes the preparation of a remediation action plan by late 2019.

Future Directions. The last fifteen years have seen some aspects of restoration, such as tree planting, proceed and expand. By some measures this is continued progress of the original project. TTL/GHP is now a well-established urban green space with environmental and amenity value. However, concerns from the early 2000s about volunteer succession, the absence of a catchment approach to management, and the need to think more strategically about ecological trade-offs between management options have been realised to some extent. The spread of Grey Mangrove is the clearest example of this. In part, some of this is perhaps inevitable for a site with the history and setting of TTL/GHP; the management context has changed, participants and stakeholders have changed, and difficult legacy issues have assumed greater prominence and cost. Nonetheless, the challenge to manage the site with a clear strategy and goals remains.

Acknowledgements: For assistance with this update, I am indebted to several past and present WCC staff, particularly Mike McKeon. I was also helped by Adam Woods, formerly of CVA, and birdwatchers Penny Potter, Terrill Nordstrom, and David Winterbottom.

Contact. Nicholas Gill, School of Geography and Sustainable Communities Faculty of Social Sciences, University of Wollongong NSW 2522 Australia, Email: ngill@uow.edu.au

Monitoring the Wunambal Gaambera Healthy Country Plan, Kimberley, Western Australia – UPDATE of EMR feature

[Update to EMR feature: Moorcroft, Heather, Emma Ignjic, Stuart Cowell, John Goonack, Sylvester Mangolomara, Janet Oobagooma, Regina Karadada, Dianna Williams and Neil Waina (2012) Conservation planning in a cross‐cultural context: the Wunambal Gaambera Healthy Country Project in the Kimberley, Western Australia,  Ecological Management & Restoration, 13:1, 16-25. See https://doi.org/10.1111/j.1442-8903.2011.00629.xk]

Key words: conservation planning, participatory conservation, Indigenous people, Kimberley

Figure 1. Location map of Wunambal Gaambera land and sea country. (Source: WGAC)

Introduction. The development of the Wunambal Gaambera Healthy Country Plan (HCP) was a key enabler for Wunambal Gaambera people to look after country (Fig 1) and occurred at an important time when native title rights to country were being secured. The plan came about through a partnership between Wunambal Gaambera Aboriginal Corporation (WGAC) and Bush Heritage Australia (BHA), who brought the planning approach and supported WGAC to develop a plan that met the needs of Traditional Owners. This plan then became the basis of a long term partnership between the two organisations to support implementation.

Healthy Country Planning, a term coined by this project, adapted the Open Standards for the Practice of Conservation (http://cmp-openstandards.org/ ) to an Indigenous native title community context. The approach has subsequently flourished in Australia, adopted by a further 30 indigenous groups ( see doi: 10.1111/emr.12267).

The unique partnership model established between BHA and WGAC, underpinned by Healthy Country Planning, has also expanded (https://www.bushheritage.org.au/what-we-do/aboriginal-partnerships). The program supports indigenous partners to achieve their community and conservation aspirations articulated through Healthy Country Planning.

Figure 2. Terrick Bin Sali handling a northern quoll (Dasyurus hallucatus). (Photo WGAC)

Conservation planning with a difference. Our experience has been that the Open Standards can be successfully applied to an Indigenous context but some important adaptation is required. For example:

  1. People, culture and country are inseparable in Australian indigenous worldviews. As such, Healthy Country Planning is much wider in scope than mainstream conservation or natural resource management planning. The vision in the HCP typically sets long-term goals that include aspirations for looking after country and achieving health conditions for landscapes, seascapes, plants and animals, as well as for people and culture (Figs 2-4). These outcomes are collectively referred to as “Healthy Country”. An indigenous plan will always recognize and value people in the landscape rather than as separate. Traditional Owners, and/or their culture, become a conservation target alongside species and habitats with ‘key cultural attributes’ established alongside ‘key ecological attributes’. HCPs also have a greater degree of management strategies that relate to people and culture than would be found in mainstream management plans, and culture and Indigenous Knowledge is incorporated into land management activities that could be considered mainstream, such as the inclusion of cultural rules within visitor management.
  2. The Open Standards include approaches and tools for stakeholder participation that lend themselves well to Indigenous peoples, however given that Indigenous lands are communally-owned and governed by unique law and culture systems, participation requirements are higher and more complex. Traditional systems of governance are often recognized under State and Federal Law (such as the Native Title Act) requiring additional process steps. In developing the HCP, WGAC undertook a process of involving all Traditional Owner families in various stages of planning and the plan was authorized at a Traditional Owner meeting.
  3. A Healthy Country Plan typically applies to the whole traditional estate of a Traditional Owner group regardless of tenure, consistent with the concept of “Country-based Planning”. WGAC initially dedicated stage I of the Uunguu Indigenous Protected Area over several aboriginal reserves in 2010, and later added exclusive possession lands following native title determination. The marine environment will also be added to the IPA once agreement is reached with State and Commonwealth Governments, as articulated in the Uunguu Wundaagu Plan.

Figure 3. Traditional Owners undertaking a ‘junba’ traditional dance workshop. (Photo: WGAC)

Monitoring & evaluation since 2012. Aspects of the monitoring and evaluation framework established by WGAC include the establishment of the Uunguu Monitoring & Evaluation Committee (UMEC) and the completion of mid-term evaluation of the HCP (see 2017 review doi:10.1111/emr.12257). The UMEC is composed of Traditional Owners and external experts who undertake key Healthy Country Planning steps and functions. A significant investment of time and money was required to support annual or biennial meetings “on country” (ie. on Wunambal Gaambera lands), however the review showed that the investment has proven worthwhile because WGAC has been able to implement the plan to a high degree.

In 2015 a major mid-term evaluation was undertaken to assess the progress of the HCP. It utilized some standard evaluation tools examining Open Standards process. It also incorporated some new approaches to include the views of the wider Traditional Owner community in the evaluation of the plan to ensure the plan was meeting their needs and following effective process with regard to governance and participation. The review made a number of observations as follows.

  1. Considerable progress had been made in the implementation of fire management strategies in the HCP to the point that the health condition of the “Right Way Fire” target was changed from ‘fair’ to ‘good’. Unmanaged wildfires have significantly reduced in size as a result of increased capabilities of the Uunguu Rangers to undertake burning. At the same time “right way” cultural principles have been incorporated into operations to ensure that Traditional Owner families are making decisions about burning and undertaking fire operations on their family areas.
  2. Significant progress has been made against a visitor management strategy. One of the key concerns of elders when developing the plan was unregulated visitation to important cultural sites by the expedition cruise industry and independent travelers. The Uunguu Visitor Pass, launched in 2017, requires visitors to obtain a permit to access authorized visitor locations as well as generating funds for looking after country. Over 90% of commercial tour operators have now registered for the UVP, with a similar independent traveler compliance, generating funds to support Traditional Owner participation in visitor management and delivering tour products.
  3. Progress was not made, however, in the health of cultural targets in the plan. As a result, the 2015 review recommended further investment and effort in culture strategies. Two important books have been completed to document elders’ knowledge of biodiversity and cultural places. There has been an increase in cultural activities including language and corroboree dance workshops and annual culture camps for school children. Law and culture dictates that visitors to country (indigenous or non-indigenous) need to be accompanied by the right local Traditional Owners when undertaking activities on country. In this way Healthy Country work supports large numbers of Traditional Owners to visit country and guide participation in the implementation of the plan. A number of actions have been undertaken to support Traditional Owners to live on country and remote ranger infrastructure has been developed.

Figure 4. Uunguu Rangers during a cultural fire walk. (Photo WGAC)

Future Directions. The first 8 years of the HCP implementation has focused on building WGAC’s land and sea management capacity and resources, with funding from WGAC,  the Australian Governments Indigenous Protected Area and Indigenous Ranger Programs and from Bush Heritage Australia. Traditional Owners currently hold certificate level roles of rangers, tourism workers and construction workers but further work is now needed to support Traditional Owners to take on roles that require higher levels of training. There is also a need to support the development of a wider range of livelihoods to support Traditional Owners to live and/or work on country.

Contact information. Wunambal Gaambera Aboriginal Corporation, PMB 16 Kalumburu via Wyndham WA 6740, Australia.

Email: info@wunambalgaambera.org.au

Web: www.wunambalgaambera.org.au

Facebook: https://www.facebook.com/uunguulife/

 

 

 

 

 

 

Seagrass restoration off the Adelaide coast using seeds and seedlings – UPDATE of EMR feature

Jason Tanner

[Update of EMR feature article :  Tanner JE, Andrew D. Irving, Milena Fernandes, Doug Fotheringham, Alicia McArdle and  Sue Murray-Jones (2014) Seagrass rehabilitation off metropolitan Adelaide: a case study of loss, action, failure and success.Ecological Restoration & Management 15: 3, 168-179.  https://onlinelibrary.wiley.com/doi/10.1111/emr.12133]

Key words:  Amphibolis, Posidonia, Recruitment facilitation, Seagrass loss

Figure 1: Bag layout for small-scale experiments on Amphibolis recruitment facilitation (top left), Amphibolis seedlings (top right), close-up of basal ‘grappling hook’ that allows seedlings to attach (bottom left), and examples of older style double-layered bags with and without seedlings attached (bottom right).

Introduction: Over the last half century or so, over 6,000 hectares of seagrass has been lost off the Adelaide coast due to anthropogenic nutrient and sediment inputs.  This loss has led to coastal erosion, decreased habitat, loss of carbon storage, and decreased fish abundance.  Recent improvements to wastewater treatment and stormwater runoff have led to some natural recovery, but changes in sand movement resulting from the loss now prevent recolonization of many areas.  Our September 2014 feature article in EMR described how SARDI have been working with other state government agencies and universities to develop a cost-effective technique to restore these areas.  Typical seagrass restoration costs on the order of AUD$1 million per hectare, but by facilitating natural recruitment of Amphibolis, yet over the last 17 years we have developed a technique that only costs a few tens of thousands of dollars.  As described in the feature, this technique uses hessian sand bags (Fig. 1) to provide a stable recruitment substrate while seedlings become established, and has resulted in the re-establishment of small trial patches of seagrass restoration (10-100 m2) which are now over 10 years old (Fig. 2) Importantly, these sites have been colonized by Posidonia and Zostera seagrasses, and provide habitat for faunal assemblages that are similar to those of nearby natural meadows, suggesting potential for small plots to act as ‘starters’ for ecosystem recovery.

Figure 2: Examples of Amphibolis restoration showing progression of establishment from 12 months (top left), 41 months (top right), 58 months (bottom left) and 8 years (bottom right).

Further work undertaken: Since our original article in EMR, we have continued monitoring the 1 hectare trial patches and expanded our focus to include additional species in the restoration, especially Posidonia.  We have also started assessing how bags degrade over time under different storage conditions, as operationalizing this technique will require bags to be stored potentially for a month or more between filling and deployment.  Importantly, the SA Government has now allocated funds for a proof of application, which will involve the deployment of hessian bags over approx. 10 hectares in late autumn 2020.

Further results to date: Two 1 hectare trials were deployed in June 2014, with 1,000 bags in each (Fig. 3).  After 9 months, these bags had an average 6.2 Amphibolis seedlings each, which was typical for bags deployed outside the winter recruitment season in previous years.  After a further 12 months, this increased to 9.2 seedlings per bag, within the range of densities previously seen for small-scale winter deployments (7-23 seedlings per bag).  A further 12 months later, densities had decreased to 3.1 seedlings per bag.  In 2017, a third 1 hectare trial was established with 2,500 bags, although these bags only had 1.2 seedlings each after 9 months. Unfortunately loss of nearly all marker stakes on all three plots due to suspected disturbance by fishing gear meant that further monitoring was not possible.  It should be noted that for the successful small-scale deployments, stem densities between 2 and 5 years were very low, and it was only after 5-7 years that success was evident.

Planting Posidonia seedlings into the bags showed good success over the first 3-4 years, with seedlings becoming established and developing into what appeared to be adult plants with multiple shoots, which did not allow individual seedlings to be identified (Fig. 4).  However, leaf densities declined substantially in the 12 months following the February 2016 survey, and recovery has been slow in the 2 years since.  Trials with different fill types (different sand/clay mixes, different amounts of organic matter added) indicated that this did not influence establishment success or growth, and neither did planting density.  Small and large seeds, however, tended to fare poorly compared to those of intermediate size (10-13 mm).  These results have been supported by short-term tank experiments, which also showed that there is only a short window for collecting fruits (those collected on 28 Dec formed an average 3.3 120 mm long leaves each after 2 ½ months, while those collected 6 days earlier or 3 days later formed < 2 leaves which were no more than 80 mm long).  After collection, fruits that did not release their seedling within 2-3 days performed poorly, and seedlings were best planted within 10 days of release. Whilst earlier Posidonia field experiments were undertaken by divers planting seedlings, which is time consuming and expensive, in 2017 seedlings were planted either onshore or on the boat, and then glued into the bags prior deployment.  This was as successful as planting underwater after 1 and 2 years, with an average 20% seedling survival, and leaf lengths of 20-25 cm, across all treatments.

Bags filled with moist sand rapidly dried out in storage, and did not deteriorate any quicker than those filled with dry sand, although it should be noted that in this experiment all bags had good air circulation around them, which would not be the case if they were stored in bulk.  Bags left outdoors exposed to the elements deteriorated quicker than those stored indoors, and pallet wrapping led to them rapidly becoming mouldy.

Figure 3: Pallets of sand bags ready for deployment (top left), and typical images of deployment

Lessons learned and future directions:  While the hessian bag method has resulted in the successful establishment of small patches of seagrasses that have persisted for around a decade, and which are now functioning like natural patches due to colonization by other marine plants and animals, the development of the technique has not been straightforward.  Refining the technique has required the development of a good understanding of the timing of recruitment, and the willingness to put conventional wisdom to the test.  This work has also required funders to take a long-term view, and to be willing to accept the fact that success cannot be established within a conventional 3-year funding cycle.  In this case, it was only 5-7 years and 2 funding cycles after deployment that we saw our small-scale trials being successful.  Now that we have established the technique at a small-scale, we are experiencing a new set of challenges with scaling up.  The 1 hectare plots have not been as successful as we had hoped.  In part, this may be due to low bag density – our small-scale plots were equivalent of approx. 10,000 bags per hectare, not the 1,000-2,500 that we have used.  Consequently, our next trial with involve a range of bag densities, from 1,000 to 10,000 bags per hectare.  In our previous article, we had indicated that we were looking at developing novel coatings to improve the life of the hessian bags, however, this proved cost prohibitive and reduced the ability of seedlings to attach to the bags.  Instead, we have now commenced a new collaboration with textile scientists to look at alternative natural fibres that might last longer than hessian but still be cheap, effective and biodegradable.

Stakeholders and Funding bodies:   SA Department for Environment & Water, SA Water, Adelaide & Mount Lofty Ranges Natural Resource Management Board, Australian Research Council, South Australian Research & Development Institute, Flinders University

Contact information: A/Prof Jason Tanner, Principal Scientist – Environmental Assessment & Rehabilitation, SARDI Aquatic Sciences, PO Box 120, Henley Beach, SA. 5022. Tel: +61 8 8429 0119. Email: jason.tanner@sa.gov.au

Figure 4: Example of Posidonia rehabilitation at time of planting (left – January 2012), after 2 years (middle – February 2014) and 4 years (right – February 2016).

 

Restoration and conservation in an iconic National Park – UPDATE of EMR feature

David Lindenmayer, Chris MacGregor, Natasha Robinson, Claire Foster, and Nick Dexter

[Update of EMR feature – David B. Lindenmayer, Christopher MacGregor, Nick Dexter, Martin Fortescue and Peter Cochrane (2013)  Booderee National Park Management: Connecting science and management.  Ecological Management & Restoration, 14:1, 2-10. https://onlinelibrary.wiley.com/doi/10.1111/emr.12027]

Keywords: Invasive animal and plant control, reintroduction, monitoring

Introduction. Booderee National Park is an iconic, species-rich, coastal reserve that supports a range of threatened and endangered native animals and plants. Several key management actions have been implemented to promote the conservation of biodiversity in Booderee National Park. These include the control of an exotic predator (the Red Fox Vulpes vulpes), the control of highly invasive Bitou Bush (Chrysanthemoides monilifera subsp. rotundata), the management of fire, and the reintroduction of previously extinct native mammals. A key part of work at Booderee National Park has been a long-term monitoring program that commenced in late 2002 and which has aimed to quantify the effectiveness of major management interventions, including the four listed above. The monitoring program has documented the long-term trajectories of populations of birds, arboreal marsupials, terrestrial mammals, reptiles, frogs and native plants in a range of major vegetation types (from heathland and sedgeland to woodland, forest and rainforest) and in response to fire, and weed and feral predator control. Importantly, the monitoring program has provided a foundational platform from which a suite of post-graduate studies and other research programs have been completed.

Further works undertaken. A key part of the researcher-manager partnership has been to analyse the long-term trajectories of populations of mammals, birds and reptiles in Booderee National Park. The monitoring data indicate that many species of mammals are declining, with some having become recently locally extinct (e.g. Greater Glider Petauroides volans) or close to extinction in the reserve (e.g. Common Ringtail Possum Pseudocheirus peregrinus) . This is despite populations of these species persisting in nearby reserves.  Robust interrogation of the multi-taxa monitoring data has been unable to identify reasons for these declines. Interestingly, the declines observed for mammals have not been observed to date in other vertebrate groups, including birds, reptiles and amphibians. An experimentally-based reintroduction program for the Greater Glider aims to not only re-establish populations of the species in Booderee National Park, but also to identify the reasons for the original decline. That program will be in addition to reintroduction programs already underway for other mammal species, the Long-nosed Potoroo (Potorous tridactylus), the Southern Brown Bandicoot (Isoodon obesulus) and Eastern Quoll (Dasyurus vivverinus) that used to inhabit Booderee National Park but which went extinct many decades earlier.

Additional research being undertaken in Booderee National Park has included: (1) studies of the effectiveness of control efforts for Bitou Bush and associated recovery of native vegetation and native fauna, (2) the interactive effects of fire and browsing on native plants and an array of animal groups, and (3) studies of leaf litter and other fuel dynamics in relation to previous fire history and macropod browsing.

Figure 1. Key area of Booderee National Park showing an area of coastal forest before and after Bitou Bush treatment.

Further results to date. Research and monitoring in the past six years have resulted in many new insights including some of considerable value for informing restoration programs. A small subset of these findings is outlined below.

  • Conventional approaches to the control of invasive Bitou Bush entail spraying ultra-low volume herbicide (Fig. 1), followed by burning of the “cured” dead material, and then respraying of the seedlings that germinate after fire. This spray-burn-spray protocol is both the most ecologically effective and the most cost-effective way of controlling Bitou Bush and, at the same time, facilitates the recovery of native vegetation. More recent analysis has revealed spray frequency as the most important determinant of long-term control. There are mixed effects of control methods on native species; plant species abundance was positively related to Bitou Bush control, while native bird abundance (except for Eastern Bristlebird Dasyornis brachypterus, Fig 2.) and mammal abundance were weakly negatively associated with Bitou control.
  • There can be strong interactions between the occurrence of fire and browsing by macropods on native plants as well as particular groups of animals such as spiders.
  • Reintroduction programs for the Southern Brown Bandicoot and Eastern Quoll have been relatively successful, although the latter species suffers high rates of mortality, particularly as a result of fox predation and collisions with motor vehicles. Nevertheless, populations of both species have survived over multiple years and reproduced successfully.

Figure 2. The Eastern Bristlebird, a species for which Booderee National Park is a stronghold. Notably, the species responds positively to management interventions to control Bitou Bush. (Photo Graeme Chapman)

Lessons learned and future directions. The work at Booderee National Park is a truly collaborative partnership between reserve managers, a university and the local Indigenous community.  A key part of the enduring, long-term success of the project has been that a full-time employee of The Australian National University has been stationed permanently in the Parks Australia office in the Jervis Bay Territory. That person (CM) works on an almost daily basis within Booderee National Park and this provides an ideal way to facilitate communication of new research and monitoring results to managers. It also enables emerging management concerns to be included as part of adaptive monitoring practices.

One of the key lessons learned from the long-term work has been the extent of ecological “surprises” – that is, highly unexpected results, including those which continue to remain unexplained. An example is the rapid loss of the Greater Glider and the major decline in populations of the Common Ringtail Possum. One of the clear benefits of this integrated monitoring-management team has been the rapid response to emerging threats. For example in response to high rates of mortality of reintroduced Eastern Quolls, control of the Red Fox was intensified within the park and greater cross-tenure control efforts with neighbouring private and public land managers have commenced. Regular evaluation of monitoring data and management actions has also enabled careful examination of the kinds of risks that can compromise reintroduction programs. These and other learnings will inform other, future reintroduction and translocation programs that are planned for Booderee National Park such as that for the Greater Glider.

Stakeholders and funding bodies. Ongoing work has been supported by many funding bodies and partners. These include the Wreck Bay Aboriginal Community who are the Traditional Owners of Booderee National Park as well as Parks Australia who co-manage the park with the Wreck Bay Aboriginal Community. Other key funders include the Department of Defence, the Thomas Foundation, The National Environmental Science Program (Threatened Species Recovery Hub), the Australian Research Council, the Margaret Middleton Foundation, and the Norman Wettenhall Foundation. Partnerships with Rewilding Australia, Taronga Conservation Society, WWF Australia, NSW Forestry Corporation and various wildlife sanctuaries have been instrumental to reintroduction programs.

Contact information. David Lindenmayer, Chris MacGregor, Natasha Robinson and Claire Foster are with the National Environmental Science Program (Threatened Species Recovery Hub), Fenner School of Environment and Society, The Australian National University (Canberra, ACT, 2601, david.lindenmayer@anu.edu.au). Nick Dexter is with Parks Australia, Jervis Bay Territory, Australia, 2540.

Lord Howe Island biodiversity restoration and protection programs, NSW, Australia

Hank Bower

Key words: Pest species management, weed control, community engagement.

Figure 1. Weeding teams apply search effort across near 80% of island terrain, their effort monitored through record of GPS track logs across designated weed management blocks. Target weeds on LHI are mostly bird dispersed requiring landscape scale for sustainable and long-term protection from weeds. The remaining 20% of island is subject to surveillance and with investigation of new technical approaches in weed detection using drones.

Introduction: Lord Howe Island (LHI) is located in the Tasman Sea 760 km northeast of Sydney and 570 km east of Port Macquarie. In 1982 the island was inscribed on the World Heritage (WH) List under the United Nations’ World Heritage Convention in recognition of its superlative natural phenomena and its rich terrestrial and marine biodiversity as an outstanding example of an island ecosystem developed from submarine volcanic activity.

The island supports at least 80% cover of native vegetation, broadly described as Oceanic Rainforest with Oceanic Cloud Forest on the mountain summits.  LHI vegetation comprises 239 native vascular plant species with 47% being endemic. Forest ecosystems on LHI are largely intact, but at threat from invasive species and climate change. About 75% of the terrestrial part of the WH property is recognised as a Permanent Park Preserve (PPP) managed on behalf of the New South Wales government by the Lord Howe Island Board on the basis of a holistic conservation and restoration plan (Lord Howe Island Biodiversity Management Plan LHI BMP 2007).

Since settlement of the island in 1834, introduced and invasive plant and animal species have been affecting the Lord Howe Island environment, causing declines in biodiversity and ecosystem health. There have been 11 known extinctions and severe declines in numbers of fauna species including the flightless Lord Howe Woodhen (Hypotaenidia sylvestris), once regarded as one of the rarest birds in the world.  The Lord Howe Island Phasmid (Dryococelus australis), the world’s largest stick insect was feared extinct until the rediscovery of live specimens on Balls Pyramid in 2001. Some 29 species of introduced vertebrates and about 271 species of introduced plant species have naturalised on the island. At least 68 species are the focus for eradication (Fig 1), with 10 main invasive species having colonised extensive areas of the settlement and the PPP, posing a serious threat to island habitats. One of the most serious weeds, Ground Asparagus (Asparagus aethiopicus), for example, was so prolific in the forest understory it completely overwhelmed native vegetation and bird breeding grounds. Weeds are prioritised for eradication following a Weed Risk Assessment and are typically species that are at low density, are localised and/or are limited to gardens, and species with known weed characteristics (e.g. wind or bird dispersed seeds) that have yet to express their weed potential. Identifying species for early intervention is important to prevent their establishment and expansion, particularly post rodent eradication. For example, the removal of 25 individual Cats Claw Creeper in 2006 (which have not been detected since) supports the case for proactive weed management.

The islands limited size and isolation provides great opportunities to achieve complete removal and eradication of key invasive species.  Therefore particular strategies identified in the LHI BMP to effect ecosystem recovery include the management and eradication of invasive weeds, rodents, tramp ants and protection from plant diseases and pathogens.  All projects are delivered at an island wide scale, which incorporates a permanent population of 350 residents and a tourist bed limit of 400.

Works undertaken   Progressive programs to eradicate feral animals commenced in 1979 with the eradication of pig Sus scrofa, cat Felus catus in 1982, goat Capra hircus in 1999 and African Big-headed Ant Pheidole megacephala in 2018. Threatened fauna recovery programs include the captive breeding of Lord Howe Woodhen following the eradication of cats, establishing a captive breeding and management program for the Lord Howe Island Phasmid and the planning and gaining of approvals to implement the eradication program for Black Rat Rattus rattus, House Mouse Mus musculus and introduced Masked Owl Tyto novehollandiae commencing in 2019.

The island wide strategic Weed Eradication Program commenced in 2004, building on earlier years of ad-hoc control effort.  Over 2.4 million weeds have been removed through more than 170,000 hours of grid search method.  Now, near mid-way point of a 30-year LHI Weed Eradication Project (LHIWEP), teams have reduced weed infestations (of all life stages) by 80%.  Ten year program results of the LHIWEP are summarised (LHIB 2016 – Breaking Bad) http://www.cabi.org/isc/abstract/20163360302, which clearly shows the significance of multi-invasive species management to achieve ecosystem recovery.

With the spread of Myrtle Rust Austropuccinia psidii to the Australian mainland in 2010 the LHI Board has been on high alert.  With five endemic plants at risk to this pathogen the LHIB provided training and information to the community on the threats to the island and food plants. The LHIB prepared a Rapid Response Plan and a Rapid Response Kit (fungicides and Personal Protective Equipment). In October 2016 Myrtle Rust was detected on exotic Myrtaceae species, from three leases and subsequently treated in November 2016. This also resulted in the eradication of three highly susceptible exotic myrtaceous plant species from the island.

The root fungus Phytophthora cinnamomi is known from one lease and has been quarantined and treated with granular fungicide quarterly. Periodic monitoring has shown the infestation to be reducing with the eventual aim of eradication. Boot sanitization stations located at all track heads applies effort to prevent introduction of root rot fungus and other soil borne pathogens from users of the walking track system in the PPP.

The LHI Board has carried out a range of local community engagement and visitor education programs to raise awareness of the risks and threats to the island environment and of the LHIB environmental restoration and protection programs. These include a LHI User Guide for visitors to the island and a citizen science program with the LHI Museum, establishing the LHI Conservation Volunteer program to help improve awareness of the importance of LHI conservation programs to both tourists and tourism business. Since 2005, over 150 volunteers supported by the LHIB and external grants have been engaged through the weed eradication project. Increasingly, LHI residents are volunteering to gain experience and to improve employment opportunities in restoring their island. Another long-term partner, Friends of Lord Howe Island, provide invaluable volunteer assistance with their Weeding Ecotours, contributing more than 24,000 hours of weeding building valuable networks.

Biosecurity awareness is critical to protect the investment in conservation programs and the environment to future threats. The LHI Board provide information regarding biosecurity risks to the community, stevedores and restaurateurs. The LHIB now hold two biosecurity detection dogs and handlers on island (Figure 3) whom work with Qantas and freight flights and shipping staff to ensure they are aware of biosecurity risks and plan for appropriate responses.

Results to date.  Achievements include the successful eradication of over 10 weed species, cat, pig, goat, African Big-headed Ant and Myrtle Rust. A further 20+ weeds are considered on the verge of being able to be declared eradicated in coming years with an 80% reduction in weed density island wide and a 90% reduction in the presence of mature weeds. Weed Risk Assessments will be applied to determine the impact or new and emerging weeds and appropriate management actions.

As a result of the eradication of feral pigs and cats and an on-island captive breeding program, the endangered Lord Howe Island Woodhen has recovered to an average of 250 birds. The other eradications, along with the significant reduction in dense and widespread weed invasions, has aided the recovery and protection of numerous endemic and threatened species and their habitats. The program’s significant outcomes have been recognised through the IUCN Conservation Outlook which in 2017 scored the Lord Howe Island Group’s outlook as good, primarily due to the success of projects that have, are being and are planned to be implemented to restore and protect the islands unique World Heritage values. In late 2018 the program received awards for excellence from the Society for Ecological Restoration Australasia (SERA), Green Globe and Banksia Foundations, acknowledging the sustained effort from the Board and Island community in working to restore and protect the island.

Lessons learned and future directions:  The main keys to success has been obtaining expert scientific and management input and actively working with, educating and involving the community (lease holders and local businesses) to help achieve the solution to mitigate and remove invasive species.

The Rodent Eradication Program scheduled for winter 2019 will result in less browsing pressure on both native and invasive plants species, as well as the removal of two domestic pests. Prior to the program the LHIB has targeted the control of introduced plants, currently in low numbers, that may spread after rodent eradication. Monitoring programs are in place to measure ecosystem response with a particular focus on the Endangered Ecological Community Gnarled Mossy Cloud Forest on the summit of Mt Gower. Should the project be successful, consideration can be given to the reintroduction of captive bred individuals of the Lord Howe Island Phasmid as well as other species confined to offshore islands (e.g. Lord Howe Wood Feeding Roach Panesthia lata) or ecological equivalent species on other islands (Norfolk Boobook Owl Ninox novaeseelandiae, Norfolk Parakeet Cyanoramphus cookii, Norfolk Island Grey Fantail Rhipidura albiscapa and Island Warbler Gerygone igata).

Stakeholders and Funding bodies:  The Program is managed by the Lord Howe Island Board and the NSW Department of Environment and Heritage, in collaboration with the local LHI community.

The LHI Board acknowledge the generations of islander stewardship, teams on ground, researchers, the funding and support agencies, all who made it happen. These include but are not limited to NSW Environmental Trust, Caring for Our Country, National Landcare Program, North Coast Local Land Services, Zoos Victoria, Taronga Zoo, Australian Museum, CSIRO, Friends of LHI, the Norman Wettenhall Foundation and Churchill Trust.

Contact: Hank Bower, Manager Environment/World Heritage, Lord Howe Island Board, PO Box 5, LORD HOWE ISLAND, NSW 2898, Tel: +61 2 65632066 (ext 23), Fax: 02 65632127, hank.bower@lhib.nsw.gov.au

Video conference presentation: https://www.aabr.org.au/portfolio-items/protecting-paradise-restoring-the-flora-and-fauna-of-world-heritage-listed-lord-howe-island-hank-bower-and-sue-bower-lhi-board-aabr-forum-2016/

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