Category Archives: Pest species

Ecological restoration in urban environments in New Zealand – UPDATE of EMR feature

Posted on 22 October 2019 by | Comments Off on Ecological restoration in urban environments in New Zealand – UPDATE of EMR feature

Bruce Clarkson, Catherine Kirby and Kiri Wallace

[Update of EMR feature  – Clarkson, B.D. & Kirby, C.L. (2016) Ecological restoration in urban environments in New Zealand. Ecological Management & Restoration, 17:3, 180-190.  https://onlinelibrary.wiley.com/doi/10.1111/emr.12229]

Key words: urban ecology; restoration; indigenous biodiversity; New Zealand

Figure 1. Kauri dieback disease is affecting individual trees (left). [Photo Nick Waipara]

Introduction. Our 2016 EMR feature reviewed the state of research and practice of ecological restoration in urban environments in New Zealand. We concluded that urban restoration can influence and support regional and national biodiversity goals. We also observed that research effort was light, lacking interdisciplinary breadth and may not be sufficiently connected to restoration practice to ensure long-term success of many projects.

While it is only three years since that review was published, urban ecological restoration continues to grow and evolve, and the policy setting and political context have changed significantly. New threats and opportunities have emerged. The spread of a dieback disease and the more recent arrival of myrtle rust, rapid uptake of Predator Free 2050, emergence of the One Billion Trees programme, a surge in housing and subdivision development, and a potentially more supportive policy framework are all major factors.

Threats and opportunities. Kauri dieback disease is severely affecting urban kauri forests and individual Kauri (Agathis australis) trees in Auckland and other northern North Island urban centres (Fig. 1). Large forest areas adjoining Auckland, including most notably the Waitākere Range and large parts of the Hunua Range, are now closed to the public, preventing access to popular recreational areas. The dieback is caused by a fungus-like pathogen Phytophtora agathicida that is spread through soil movement. The disease may have arrived from overseas although this is uncertain. There is no known cure but research efforts are underway to find a large-scale treatment option.

Myrtle rust (Austropuccinia psidii) was first found on mainland New Zealand in May of 2017, probably arriving by wind from Australia. Myrtle rust threatens many iconic New Zealand plant species in the family Myrtaceae including Pōhutukawa (Metrosideros excelsa), Mānuka (Leptospermum scoparium), Rātā (Metrosideros robusta), Kānuka (Kunzea spp.), Waiwaka (Syzygium maire) or Swamp maire, and Ramarama (Lophomyrtus bullata). These species are all used to a greater or lesser extent in restoration planting or as specimen trees or shrubs in urban centres, depending on amenity or ecological context. Mānuka is widely used as a pioneer or nurse crop for native forest restoration and is critical to the economically important mānuka honey industry. Waiwaka is a feature of many swamp forest gully restoration projects in Hamilton and this would be a significant setback if they were badly affected. The impact of myrtle rust is still not clear but experience from Australia suggests it may take several years before it reaches population levels sufficient to cause significant damage.

Figure 2. With rapid housing developments in New Zealand, it is important that urban restoration projects are well-planned and efficiently carried out to provide residents with greenspaces to benefit their cultural, health and wellbeing practices. [Photo Catherine Kirby]

In response to a range of housing issues characterised by many as a New Zealand housing crisis, the previous and current government has embarked on several major initiatives to increase the housing stock. A $1B Housing Infrastructure Fund (HIF) was established in October 2016 with provision for interest free loans to local government to enable opening up of new large areas of housing. Many urban centres including Auckland, Tauranga, Hamilton and Queenstown made early applications to the fund. Hamilton City Council was successful in obtaining $290.4 M support for a new greenfield subdivision in Peacocke on the southern edge of the city. This subdivision is intended to enable development of some 3700 houses over the next 10 years and 8100 in 30 years. Approximately 720 ha of peri-urban pastoral agricultural land would eventually be developed (See summary). Coupled with this, and already in progress, is the construction of the Southern Links state highway and local arterial road network. The first proposed subdivision Amberfield covers 105 ha and consent hearings are currently in progress. The environmental impacts of the proposal and how they might be mitigated are being contested. In brief, survival of a small population of the critically endangered Long-tailed Bat (Chalinolobos turberculatus) is the main environmental focus but other aspects including the extent of greenspace and ecological restoration required for ecological compensation are being considered (Figs. 2, 3). With strong political pressure to solve the housing crisis in Hamilton and in other urban centres, making adequate provision for greenspace, especially urban forest, and preventing environmental degradation and indigenous biodiversity decline will be a major challenge.

Figure 3. Aerial photo of Waiwhakareke Natural Heritage Park (65 ha), an award-winning and ongoing ecological restoration project situated on the edge of urban Hamilton. [Photo Dave Norris]

The Predator Free 2050 (PF2050) programme which gained government (National) approval in 2015, aims to eradicate Stoat (Mustela erminea), Ship Rat (Rattus rattus), Norway Rat (Rattus norvegicus) and Possum (Trichosurus vulpecula) from the whole of New Zealand by 2050 (Department of Conservation 2018). PF2050 is now gaining significant traction in urban environments (Figs. 4, 5) with many urban centres having good numbers of community-led projects underway (See PFNZ National Trust map). Crofton Downs in Wellington was New Zealand’s first predator-free community project. Led by Kelvin Hastie this project has effectively reduced predator numbers to the point that some sensitive native birds e.g. Kākā (Nestor meridionalis), have begun to nest in this suburb after an absence of more than 100 years (See RNZ report). Also in Wellington, the Miramar Peninsula (Te Motu Kairangi) has become a focus, because of its advantageous geography, with a goal to make the area predator free by 2019. Possums had already been exterminated in 2006 (www.temotukairangi.co.nz).

Figure 4. John Innes (Wildlife Ecologist, Manaaki Whenua Landcare Research) demonstrating trapping success. Removing pest mammals reduces predation, and also frees up the habitat and resources for our native fauna and flora to flourish. [Photo Neil Fitzgerald]

The One Billion Trees (1BT) programme was initiated by the new coalition government (Labour, NZ First, Greens) in 2017 with $238M released in 2018 for planting of both exotic and native trees across mixed land use types. It is not clear yet whether urban forest projects have received funding support but the guidelines suggest there is no reason why restoration of native forest in urban settings would not be eligible. While the emphasis is on exotic tree plantations, native species and long-term forest protection are increasingly being considered as viable options by the newly established government forestry agency Te Uru Rākau.

The policy setting for ecological restoration in urban environments is potentially becoming more favourable with the draft National Policy Statement on Indigenous Biodiversity (NPSIB) currently in review and the New Zealand Biodiversity Strategy under revision (See terms of reference). The draft NPSIB emphasises restoration of indigenous habitat in biodiversity depleted environments. Specifically, Policy 19: Restoring indigenous biodiversity depleted environments, recommends a target for indigenous land cover, which in urban areas and peri-urban areas must be at least 10 per cent. The revision of the New Zealand Biodiversity Strategy seems likely to give more emphasis to landscape scale restoration including urban environments.

Figure 5. New Zealand native lizards are extremely vulnerable to mammalian predation (e.g. mice, hedgehogs, ferrets, cats) as well as habitat destruction (e.g. new urban developments). [Photo Tony Wills]

Research update. Using the same targeted Google Scholar search method as reported in the EMR feature we have found 18 new peer reviewed papers published between 2015 and July 2019 (see updated bibliography) that are strongly focused on restoration in New Zealand urban environments. The single paper noted for 2015 was missed in our previous search. Again, we have not included books, book chapters or grey literature. This compares very favourably with the total 27 papers listed in our 2016 review of which more than half dated from 2009. An increasing publication rate confirms increasing interest and research efforts in aspects of urban ecological restoration. While most of the publications remain in the ecological science realm there are now some informed by other disciplines including engineering, psychology, landscape architecture and health sciences.

Most notably since our 2016 review, a new government-funded (Ministry of Business, Innovation and Employment) research programme, People, Cities and Nature, began in November of 2016. This four-year $823 k per annum research programme ends in October of 2020 unless a funding rebid to be submitted in March 2020 is successful. The programme undertakes multidisciplinary research in nine NZ cities via six inter-related projects: restoration plantings; urban lizards; mammalian predators; Māori restoration values; green-space benefits and cross-sector alliances. While the emphasis was on the ecological science of urban restoration at the outset, the programme has become increasingly involved in understanding the multiple benefits of urban ecological projects including social cohesion and health and recreation benefits. The need to connect restoration research and practice has been met by undertaking multi-agency and community workshops involving researchers and practitioners in five cities to date with a further four scheduled before the programme ends.

Acknowledgements. The People Cities and Nature research programme is funded by the Ministry of Business Innovation and Employment under grant number UOW1601.

Information. Bruce D. Clarkson, Environmental Research Institute, University of Waikato, Hamilton, New Zealand bruce.clarkson@waikato.ac.nz; Catherine L. Kirby, Environmental Research Institute, University of Waikato, Hamilton, New Zealand catherine.kirby@waikato.ac.nz; and Kiri J. Wallace, Environmental Research Institute, University of Waikato, Hamilton, New Zealand kiri.wallace@waikato.ac.nz.

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Posted in Community involvement, Cultural & socio-economic issues & solutions, Education & communication, EMR 20th anniversary updates, Fauna & habitat, New Zealand, Pest species, Podocarp forest, reconstruction, Threatened species & communities, Uncategorized, Urban ecosystems, Wetland

The rise of invasive ant eradications since the success of the Kakadu project  – UPDATE of EMR feature

Posted on 3 October 2019 by | Comments Off on The rise of invasive ant eradications since the success of the Kakadu project  – UPDATE of EMR feature

Benjamin D Hoffmann

[Update of EMR feature – Hoffmann,  Benjamin D and Simon O’Connor (2004) Eradication of two exotic ants from Kakadu National Park. Ecological Management & Restoration, 5:2, 98-105. https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2004.00182.x]

Key words. pest species management, invasive species, biosecurity

Figure 1. Kakadu staff in 2001 spreading formicide over a super-colony of African Big-headed Ant. This involved a team of people, aligned in a row, walking from one edge of the infested area to the other in parallel paths. (Photo courtesy of Simon O’Connor.)

Introduction. Invasive species management, especially eradications, has been at the forefront of biodiversity conservation gains over the past two decades. For example, over 1,200 invasive vertebrate eradications have been achieved on over 800 islands worldwide and the conservation benefits of such actions have been overwhelmingly positive and often dramatic. Efforts against invasive ants have also been particularly notable over the past two decades, with ants now being the second-most eradicated taxa globally having been eradicated from more than 150 locations, with the largest eradication covering 8300 ha. Two decades ago there were only 12 confirmed ant eradications using modern baits with a combined area totalling a mere 12 ha.

As reported in our original EMR feature, the last treatments against two invasive ants in Kakadu National Park, northern Australia: The African Big-headed Ant (Pheidole megacephala) and the Tropical Fire Ant, (Solenopsis geminata) were conducted in 2003; and the ants were declared eradicated two years later (Hoffmann & O’Connor 2004). At the time this was a globally significant eradication, and the positive outcome was a partial catalyst for the creation of many other relatively small exotic ant eradication attempts around Australia, including against Tropical Fire Ant on Melville island, and African Big-headed Ant on Lord Howe Island. Incidentally, the work coincided with the approximate timeframe of when two other highly invasive ant species were first detected in Australia: Red Imported Fire Ant (RIFA) (Solenopsis invicta), and Electric Ant (Wasmannia auropunctata), prompting the initiation of two massive national cost-shared eradication programs. One of these, the RIFA program, has become Australia’s second-most expensive eradication program at AUD $428 million as of at July 2019. Together, all of these actions put ants high on Australia’s biosecurity and environmental management radars, prompting the development of Australia’s Tramp Ant Threat Abatement Plan and yet even more eradication programs.

Figure 2. Ant bait being dispersed aerially by helicopter using an underslung spreader and side-mounted dispersers. (Photos Ben Hoffmann)

Further advancements in ant eradication programs.  As Australia’s eradication programs became more numerous and larger, it became apparent very quickly that the methodologies and technologies available were insufficient to achieve success in the increasingly challenging conditions being encountered. In response, over the next two decades, there has been an impressive range of advancements that significantly improved our capacity to manage and eradicate invasive ant incursions.

The biggest issue was that work needed to be conducted over such large or inaccessible areas that ground-based work (Fig 1) was not feasible. So, treatments quickly became aerial, using multiple helicopter-based delivery platforms (e.g. underslung buckets and side-mounted hoppers, Fig 2). Even so, there have been locations that are too remote, too small, or too difficult (ie cliffs) to treat using a helicopter. To meet this challenge, in just the last five years treatments have been conducted for the first time using drones, and there is a great focus now to improve the technology so that it becomes more cost effective and more autonomous (Fig 3). This is occurring at such a pace that just a few years ago drones could only operate for a few hours at most on battery power, and only carry a few kilograms. This year we will be using a drone with unlimited flying capacity (petrol driven) that can lift 70 kg per load.

Figure 3. The Fazer with side-mounted bait carriers that can lift up to 40kg of payload. This is soon to be superseded by a drone that can lift a 70k g payload. (Photo Ben Hoffmann)

Assessments for the presence of ants, either before or after treatments, was originally very time consuming, involving teams of people walking ground very slowly and often utilising thousands of attractive lures (Fig 4). At most, only small ant populations (about less than 20 ha) within good working environments (ie open landscapes) could be assessed using teams of people, and it took large amounts of time. It was found very quickly that detector dogs could be trained on the scent of each ant species, and a single dog could cover more than five times the area of a team of people in a single day with greater efficacy (Fig 5). There are now more than 20 detector dogs operating in Australia and New Zealand that have been trained on the scent of four ant species. But even a team of dogs cannot fully cover entire areas at the landscape-scale, such as is the case for the RIFA program, especially in areas with long grass or rugged terrain. One of the saving technologies for the RIFA program has been the development of a multi-spectral sensor and associated algorithms that can identify RIFA nests from imagery captured by remote sensing (Fig 6). This allows program staff to assess just a few identified point locations in a landscape rather than the entirety of landscapes, to determine RIFA presence or absence. The next envisaged step is the development of biosensors that can detect the odours of target ant species, just like detector dogs, and with time these will become small enough to be transported by small drones throughout landscapes to detect ants.

Figure 4. An area covered with hundreds of flags marking spoonfulls of catfood being used as lures to attract African big-headed ant to assess eradication success or failure. (Photo Ben Hoffmann)

Figure 5. An ant detector dog searching for the presence of Red imported fire ant. (Photo courtesy of The State of Queensland (Department of Agriculture and Fisheries 2010–2019))

Australia was caught particularly unprepared two decades ago when the two new exotic ant species were detected for the first time because there were no baits registered for their management in Australia, so legally there were no treatment products that could be used. Even with the implementation of Emergency Use Permits for some unregistered products, as well as the use of the few products that were available for other species, it was often found that individual products could not be used in particular circumstances, especially around water, within crops and on organic farms. Additionally, available baits often did not have high efficacy. With time many baits (comprised of combinations of an attractive food laced with an active constituent) have been formulated and tested providing a greater array of baits that can be used on any new incursion and in numerous settings. The most recent has been the development of hydrogel baits that essentially deliver a liquid product in a solid form.

Figure 6 a and b. Multi-spectral camera flown underneath a helicopter to detect Red imported fire ant nests. (Photos courtesy of The State of Queensland (Department of Agriculture and Fisheries) 2010–2019)

Among the numerous advances described already, possibly the greatest development is on the threshold of becoming a reality, in the form of genomic solutions for individual species. RNA interference, and gene-drive technology are rapidly being developed for a suite of economically important species, and ants are among the taxa that are highest on the priority list as targets for this research. At best, these genomic advances promise to provide species-specific solutions, thereby alleviating the current non-target issues of using toxicants.

Conclusion. Our ability to eradicate ants has improved dramatically over the past two decades, with technologies and methodologies available now that were as yet not thought of back when our work was conducted in Kakadu National Park. New programs are constantly arising, and forging ahead in increasingly challenging situations, and a great deal of effort is placed in information-sharing among programs. Simultaneously there is a sustained focus to improve biosecurity at Australia’s borders, as well as throughout our region to help prevent the need for eradications in the first place.

Contact. Ben Hoffmann, Principal Research Scientist, CSIRO Health & Biosecurity (PMB 44 Winnellie NT 0822 Australia; Tel: +61 8 89448432; Email: Ben.Hoffmann@csiro.au).

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Posted in EMR 20th anniversary updates, Fauna & habitat, Indigenous land & sea management, Monitoring, Northern Territory, Pest animal issues & solutions, Pest species, Restoration & management theory, Techniques & methodology

Eradication of Red Imported Fire Ants in Australia (NRIFAEP Brisbane) – UPDATE to EMR feature

Posted on 25 September 2019 by | Comments Off on Eradication of Red Imported Fire Ants in Australia (NRIFAEP Brisbane) – UPDATE to EMR feature

Ross Wylie and Melinda K. McNaught

[Update to EMR feature – Wylie, Ross,  Craig Jennings, Melinda K. McNaught, Jane Oakey, Evan J. Harris (2016) Eradication of two incursions of the Red Imported Fire Ant in Queensland, Australia.  Ecological Management & Restoration, 17:1, 22-32. https://onlinelibrary.wiley.com/doi/10.1111/emr.12197]

Key words. control, invasive ants, Queensland, Solenopsis invicta

Figure 1. Map showing quarantine intercepts, postquarantine detections, and known incursions of Red Imported Fire Ant across Australia. Inset shows the detections and incursions found in Brisbane, Queensland, with Table 1 listing further details for each.

Introduction. The highly invasive Red Imported Fire Ant (Solenopsis invicta Buren) was officially identified in Brisbane, Australia in 2001. A nationally funded eradication programme began in that year and is ongoing. As of 2015, five known incursions – determined by genetically assigning population origin – had been identified across Queensland and New South Wales. In our paper we highlighted that two of these populations have been officially eradicated, and that eradication was still considered feasible for the remaining three.

Further work undertaken. In 2015, modelling showed that the extent of the southeast Queensland infestation had been delimited with a 99.9% level of confidence. Delimitation was achieved in part using newly developed remote sensing technology, which enabled large areas to be rapidly surveyed for Red Imported Fire Ant at affordable cost, and with the assistance of the public in looking for and reporting suspect ants. While this does not guarantee that eradication will ultimately be achieved, or that delimitation failure will not recur sometime in the future, establishing that the invasion has been delimited is an essential prerequisite to the ultimate success of the programme. In 2016, an independent review of the operation and management of the programme and of the tools and strategies it employed concluded that eradication was still technically feasible, cost-beneficial and in the national interest, and that efforts should continue.

In 2017, a national cost-sharing consortium of Federal, State and Territory governments approved funding of $A411 million for a new ten-year programme to finish the job.

Further results to date. We confirm that the infestations at the Port of Gladstone in 2013 and Port Botany in 2014, reported in our 2016 paper as still undergoing eradication treatment, have now officially been declared eradicated (see Table 1). Since then, there have been two additional incursions in southeast Queensland; one at the Brisbane airport in 2015 and another at the Port of Brisbane in 2016 (see Figure 1).

Genetics analysis revealed that both of these detections were new incursions and not related to existing or previous populations in Australia. Although only a few nests were found, the presence of winged reproductives in these nests signalled the possibility that there may have been dispersal by flight prior to discovery. Consequently, a full eradication response was mounted for each incursion. These responses entailed destruction of any detected nests using a contact insecticide and surveillance out to a radius of 5 km to determine the extent of the infestation. Following this, six rounds of treatment over two years were applied to a radius of 500 m around detected nests using baits containing insect growth regulators. At the completion of treatment, two rounds of surveillance, one year apart, were conducted using odour detection dogs with no ants found. Brisbane Airport was declared eradicated in 2019, and declaration is pending for the Port of Brisbane.

Table 1. Chronology of known Red Imported Fire Ant incursions and postquarantine detections in Australia.

Year Detection Country of Origin Location Status
2001 Incursion United States Port of Brisbane, Qld Last nest found Feb 2005; declared eradicated in 2012
2001 Incursion United States Richlands, Brisbane, Qld Eradication in progress; focus of the Ten Year Plan
2004 Postquarantine detection Unknown Port of Brisbane, Qld Destroyed
2006 Incursion Argentina Yarwun, Qld Last nest found Sept 2006; declared eradicated in 2010
2009 Postquarantine detection United States Lytton, Brisbane, Qld Destroyed
2011 Postquarantine detection United States Roma, Qld Destroyed
2013 Incursion United States Port of Gladstone, Qld Last nest found Sept 2014; declared eradicated in 2016
2014 Incursion Argentina Port Botany, Sydney, NSW Last nest found Dec 2014; area freedom declared 2016
2015 Incursion United States Brisbane Airport, Qld Last nest found Sept 2015; declared eradicated in 2019
2016 Incursion Argentina Port of Brisbane, Qld Last nest found May 2016; response complete and declaration of eradication pending.

Lessons learned and future directions. Genetic testing continues to be one of the programme’s most valuable tools in the effort to eradicate Red Imported Fire Ant from Australia and has broader application for other pest eradication programmes. The 2016 Port of Brisbane incursion was shown to have originated from Argentina and was therefore not a remnant from the original 2001 incursion at the Port, which came from the southern United States and whose genotype has not been detected in Australia since 2005. Additionally, genetics showed that it was unrelated to the 2006 incursion at Yarwun or the 2014 incursion at Port Botany, Sydney, both of which came from Argentina. Without such information, the programme would be unable to prove that these incursions were not the result of treatment failure or movement from existing populations in Australia.

As mentioned in our 2016 paper, one of the features characteristic of successful eradication programmes worldwide is that resources must be adequate and there must be commitment to see the project through to completion. In Australia, inadequate resourcing at various times in the programme’s history has threatened the possibility of eradication success. This was most notable in 2006 when, with eradication seemingly on track, a significant downsizing of the programme occurred just prior to the discovery in 2007 of major new infestations outside the known infested area. There was no commensurate increase in resourcing to deal with these finds and for several years the programme adopted a suppression and containment strategy while new tools for detecting and eradicating the pest were developed. A major factor contributing to the funding uncertainty post-2007 was the programme’s failure to delimit properly the extent of the infestation in southeast Queensland. This is a key, albeit basic, lesson for any eradication programme. However, following delimitation in 2015, the national cost-sharing consortium again demonstrated their commitment in 2017 to a programme that had been in operation for 16 years, at a cost of $A347 million, by approving a ten-year, $A411 million extension.

Lastly, the programme’s successes to date have reinforced the generally accepted biosecurity principle that the earlier detection of an exotic organism, the better the chance of eradication. Three of the seven Australian incursions have been at ports of entry with relatively few colonies detected and all were eradicated. The same applies for the three incursions in New Zealand. The larger incursions in central Queensland at Yarwun in 2006 (71 ha) and Port of Gladstone in 2013 (220 ha) were shown by analysis of import timelines and by genetics to be of less than three years’ duration and both were successfully eradicated.

This contrasts with the situation in the United States and China where the ‘war’ against Red Imported Fire Ant has been lost; the ant is believed to have been present in the US for around 15 years before eradication efforts commenced and in China for 10 years. Taiwan’s two incursions were likely present for 3–5 years .before discovery, and in 2017, it claimed eradication of one of these populations at Chiayi. Recent reverse-spread modelling has confirmed that the initial Red Imported Fire Ant incursions in Brisbane occurred in the early 1990s, about 10 years before its official discovery in 2001 (Daniel Spring, 2019, personal communication). This makes the eradication of the 2001 Port of Brisbane infestation (8300 ha) significant, in that it demonstrates that eradication is achievable even for a long-established population.

The programme is now in the second year of the ten-year eradication programme. This entails a staged approach, with eradication treatments commencing in the west of the known infestation area and moving to the east, while at the same time suppressing populations in areas awaiting eradication and containing spread. Several new initiatives are underway, including engaging the public and businesses in self-treatment to assist the eradication effort, and the development of novel treatment technologies.

Stakeholders and funding bodies. Australian Commonwealth, States and Territories

Contact information. Dr Ross Wylie, Science Leader, Biosecurity Queensland (Department of Agriculture and Fisheries, PO Box 426 Browns Plains BC Queensland 4118; Tel: +61 7 33304621 Email: ross.wylie@daf.qld.gov.au). Dr Melinda McNaught, Scientist, Biosecurity Queensland (Department of Agriculture and Fisheries, PO Box 426 Browns Plains BC Queensland 4118; Tel: +61 7 33304622; Email: melinda.mcnaught@daf.qld.gov.au).

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Posted in EMR 20th anniversary updates, Pest animal issues & solutions, Pest species, Queensland, Urban ecosystems

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

Posted on 27 June 2019 by | Comments Off on 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.

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Posted in Assisted regeneration, Coastal & marine, Community involvement, EMR 20th anniversary updates, Fauna & habitat, faunal reintroduction, Fire Ecology & Management, Indigenous land & sea management, Monitoring, Pest animal issues & solutions, Pest species, Rainforest, Reserve management, Restoration & management theory, Sclerophyll communities, Threatened species & communities, Uncategorized, Weed issues & solutions, Wetland

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

Posted on 20 December 2018 by | Comments Off on 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/

Also see updates of rodent eradication program:

https://lhirodenteradicationproject.org/

https://www.environment.nsw.gov.au/news/rodent-eradication-gives-lord-howe-biodiversity-boom

https://www.abc.net.au/news/2021-02-02/lord-howe-island-recovers-from-rat-infestation/13111770

https://www.theguardian.com/australia-news/2021/apr/19/rats-reappear-on-lord-howe-island-for-the-first-time-since-2019-eradication-program

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Posted in Bush regeneration, Coastal & marine, Community involvement, Education & communication, Fauna & habitat, faunal reintroduction, Island restoration, Monitoring, New South Wales, Pest animal issues & solutions, Pest species, Reserve management, Techniques & methodology, Threatened species & communities

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

Posted on 4 November 2017 by | Comments Off on 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

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Posted in agricultural lands, Coastal & marine, Community involvement, Cultural & socio-economic issues & solutions, Education & communication, Fauna & habitat, faunal reintroduction, History, Island restoration, Monitoring, New Zealand, Pest species, reconstruction, Threatened species & communities

Arid Recovery – Roxby Downs, South Australia

Posted on 15 March 2016 by | Comments Off on Arid Recovery – Roxby Downs, South Australia

Key words. Feral-proof fence, native animal reintroductions, feral animal control.

Introduction. Arid Recovery is a conservation research initiative based in the South Australian arid zone and dedicated to the restoration of Australia’s arid lands. Established in 1997, the program is centred around a 123km² fenced reserve but it is continually expanding into the wider region. Feral cats, rabbits and foxes have been eradicated from a total of 60km² and this has provided an area of complete protection into which four species of locally extinct mammals have so far been reintroduced.

Although the fenced reserve provides a core area for animal re-introductions, the long term aim of Arid Recovery is to develop broadscale control techniques for feral animals to facilitate the restoration of the entire arid zone ecosystem including re-introducing herbivores, predators and insectivores to create a natural functioning ecosystem that requires minimal management. Specific goals include to:

  • eradicate feral cats, foxes and rabbits and re-establish native species,
  • research and monitor the processes of ecological restoration and provide transferable information and techniques for broadscale management of Australia’s arid lands

Arid Recovery is also committed to increasing education and awareness of arid zone issues and has an education program that includes indigenous youth and local schools.

Degradation. At least 27 species of native mammal once inhabited the Roxby Downs region but over 60% have become locally or completely extinct since European settlement. Some bird species such as the Bush Thick-knee and Plains Wanderer have also become locally extinct or endangered.

The main reasons for the decline of the local native fauna and flora are overgrazing by rabbits and domestic stock, and predation from introduced animals like the feral cat and fox. Medium-sized desert mammals have been most affected with many now globally extinct or have disappeared from mainland Australia and survive only on off-shore islands.

Since the inception of grazing in arid rangelands, there have been extensive vegetation changes. Many parts of arid Australia were severely over-grazed by sheep and cattle during the advent of pastoralism in the 19th Century. Overgrazing by domestic stock and rabbits has a significant effect on arid zone vegetation; long-lived arid zone trees and shrubs are prevented from regenerating, and long-lived plant species are being replaced by short-lived annual and weed species. Whilst current pastoral practices are much more conservative there are still many areas degraded by pastoralism.

Our restoration work. A feral-proof fence has been designed and installed to protect a total area of 123km². The fence was built in blocks and to date, 123 square km of arid land has been fenced and control programs implemented for rabbits, cats and foxes (Fig 1.) . Six locally-extinct threatened species were reintroduced: Greater Stick Nest Rat (Leporillus conditor), Burrowing Bettong (Bettongia lesueur), Greater Bilby (Macrotis lagotis), Western Barred Bandicoot (Perameles bougainville), Numbat (Myrmecobius fasciatus) and Woma Python (Aspidites ramsayi). (See results below.)

Figure 1. Map of the reserve showing cumulative addition of fenced areas.

Figure 1. Map of the reserve showing cumulative addition of fenced areas.

Monitoring. More than 500 monitoring sites have been established to document the restoration process including annual pitfall trapping, burrow monitoring, seedling counts, photopoints and spoor counts. Recruitment of seedlings is monitored inside and outside the Arid Recovery Reserve to determine the impact of rabbits and domestic stock on the survival of seedlings.

Results of our work.

  • Rabbits, cats and foxes have been eradicated from 60 square km pf the Arid Recovery Reserve.
  • Four of the mammal species (Greater Stick Nest Rat, Burrowing Bettong, Greater Bilby and Western Barred Bandicoot) were successfully reintroduced. The Numbat and Woma Python reintroductions were unsuccessful,
  • The fence design has now been adopted by many projects both within Australia and internationally (e.g. Hawaii, Queensland). Results from 10 years of pitfall trapping show that native rodents have now increased to 10 times inside the Reserve compared to outside areas where cats and foxes are still present.
  • Results of the monitoring of plant recruitment to date suggest that survival of Mulga (Acacia aneura) seedlings is much higher where rabbits and grazing pressure by other herbivores has been removed.

Research program. Where published information or advice was not available, Arid Recovery implemented its own research programs to test various on-ground techniques and then adopted the most effective methods. Arid Recovery’s four co-founders are all ecologists and have ensured that all management and monitoring has an adaptive management focus and that overall ecosystem restoration is more important than single species recovery.

The University of Adelaide is a partner organisation and has provided research students, scientific advice and staff management. Research into effective rabbit and cat control methods has now been published for use by other land managers. Research has been conducted into the ecosystem services provided by re-introduced Bilbies including the increased soil carbon levels and water infiltration recorded within their foraging pits.

Long term monitoring sites have provided critical information on both fauna and flora recovery of in situ species and an insight into their threatening processes. More than 40 scientific papers, internal reports and theses and 25 conference presentations have been produced to date and Arid Recovery is committed to effective dissemination of information to landholders not just the scientific community. Publications in National Landcare Magazine and participation in local NRM fora ensure that the scientific information is transformed into easily digestible and practical land management applications.

Further directions. Arid Recovery is now researching ways to move beyond the fenced reserve through improved predator management and increasing the predator-awareness of threatened species. Another current and future direction is preventing overpopulation of reintroduced species within the reserve through the use of one way gates and predators. Arid Recovery has recently partnered with Bush Heritage to form the South Australian Rangelands Alliance (SARA) with both organisations aiming to restore the plants and animals in the arid zone.

Lessons learned. The partnership between industry, government, community and research institutions has been integral to the success of Arid Recovery. Each partner has brought skills, resources and expertise to the program and ensured a balance is achieved in ecological restoration activities.

The winning combination of solid on-ground works and adaptive management based on sound scientific research is the key to Arid Recovery’s success. By ensuring that effective monitoring is regularly conducted and reviewed, Arid Recovery staff are able to implement changes to reserve management effectively and quickly.

Another important lesson learned is that restoration does not happen on its own, it requires long hours of hard work from both staff and volunteers. Arid Recovery is indebted to the hundreds of people who have given up their time to shoot cats, trap rabbits, count birds, measure plants and most importantly erect fencing.

Stakeholders. Arid Recovery is a partnership between BHP Billiton, S.A. Department for Environment, University of Adelaide and the Friends of Arid Recovery. All four partners contribute funding and in kind contributions and have committed to long term support for the program.

Contact. Please contact Arid Recovery for more information on :  (08) 8671 2402 or www.aridrecovery.org

See also: One-way gates: Initial trial of a potential tool for preventing overpopulation within fenced reserves

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Posted in arid, Fauna & habitat, faunal reintroduction, Pest species, Reserve management, South Australia, Standards

Saltmarsh translocation and construction, Penrhyn Estuary, Port Botany, NSW

Posted on 7 March 2016 by | Comments Off on Saltmarsh translocation and construction, Penrhyn Estuary, Port Botany, NSW

Mia Dalby-Ball and Andre Olson

From June 2008 to June 2011, ecological restoration work was conducted by Port Authority of NSW in association with the expansion of the port at Port Botany, Sydney, NSW. The purpose was to expand and rehabilitate Penrhyn Estuary.

The saltmarsh works at Penrhyn Estuary involved 2.4 hectares being densely planted with saltmarsh species. In addition to this 3000m2 of saltmarsh was translocated within Penrhyn Estuary. The key driver for the saltmarsh design and plant selection was the requirement for the project to provide habitat for migratory wading birds.

There were many key aspects to the project. Primary among them was the engagement of an expert to undertake a pre-words evaluation and design the wetland construction. It was also important that planning involved representatives from different disciplines including those who would be doing the on-ground work and those monitoring migratory birds. Another key aspect was that approvals and licenses were identified and obtained early.

Saltmarsh construction. Seed collection (from local sources) and plant growing was carried out more than a year before plants were required. (This is because saltmarsh plants are slow to grow, there is a narrow window of time for seed collection and permits are required to collect seed or pieces.)

Implementation works first involved removal of dune weeds (Bitou-Bush, Chrysanthemum monilifera ssp. rotundifolia) and saltmarsh weeds, in particular Spiny Rush (Juncus acutus) of which large plants were hand removed and or cut and painted with herbicide. Germinating seedlings were irrigated with Saltwater. Monthly inspections undertaken with immediate removal of new plants.

This was followed by excavation of land so that it became inundated by monthly high tides. (Monitoring of tidal inundation was carried out to test that levels were appropriate and areas that had water pooling in excess of five days were filled.)

Soil conditioner (organic rich soil) was spread over the sandy substrate and mixed to 100mm, using cultivation equipment. This was followed by planting of over 250,000 saltmarsh plants including of Beaded Glasswort (Sarcocornia quinqueflora) and Salt Couch (Sporobolus virginicus). All saltmarsh plantings were irrigated with fresh water via a sprinkler system.

Fig 1. Translocating Beaded Glasswort via electric boat. (Photo: Dragonfly Environmental)

Fig 1. Translocating Beaded Glasswort via electric boat. (Photo: Dragonfly Environmental)

Translocation of saltmarsh. A 3000m2 area of Beaded Glasswort and Salt Couch was growing on an area that was to be excavated to become mudflats. This area was cut into ~ 20cm x 20cm blocks with 100mm deep soil and lifted by hand (shovels) and put onto wooden sheets (plywood) and transported to the recipient site. Transportation was chiefly by a small boat with electric motor (Fig 1).

The saltmarsh was translocated to the site where the Spiny Rush had been removed. At the recipient site it was planted into the substrate (Fig 2). Spaces between blocks were filled with soil from the donor site. The entire area was irrigated thoroughly with salt water. Irrigation continued for six months while the transplanted material established.

Monitoring. Monitoring existing saltmarsh and proposed saltmarsh creation sites prior to, during and for 2 years post works. Additional monitoring has been conducted for a further 3 years.

Fig 2. Transplanting clumps of Beaded Glasswort and Salt Couch into areas where Spiny Rush had been removed. (Photo: Dragonfly Environmental)

Fig 2. Transplanting clumps of Beaded Glasswort and Salt Couch into areas where Spiny Rush had been removed. (Photo: Dragonfly Environmental)

Fig 3. Sprinkler irrigation during saltmarsh planting. Fresh water irrigation continued for at least 6 months post-planting. (Photo: Dragonfly Environmental)

Fig 3. Sprinkler irrigation during saltmarsh planting. Fresh water irrigation continued for at least 6 months post-planting. (Photo: Dragonfly Environmental)

Lessons learned. At over 230,000 saltmarsh plantings, to our knowledge this is the largest recorded saltmarsh construction project recorded to date. A number of findings have resulted from the project, particularly our trials to arrive at a suitable growing medium for the plantings. We sought a soil that had free drainage good moisture retention properties and contained available nutrients. Fertiliser tablets alone are insufficient in sandy soils. We trialed a range of soil conditioners, with the most successful having high organic content and did not float. Irrigation is required as tidal inundation is not adequate to keep soil moist for seedlings. We found that irrigation was required for at least 6 months

Acknowledgements: Design and pre-works site evaluation was conducted by Geoff Sainty of Sainty and Associates and BioAnalysis.  Implementation and monitoring of saltmarsh during construction and establishment phase (two years monitoring) was carried out by Dragonfly Environmental.  Cardno (NSW/ACT) has been conducting environmental monitoring post establishment phase.

Contact: Mia Dalby-Ball, Ecological Consultants Australia, 30 Palmgrove Road,  Avalon NSW 2107, Australia (Tel: 0488 481 929; Email: ecologicalca@outlook.com) or Andre Olson, Dragonfly Environmental, 1/33 Avalon Parade, Avalon NSW 2107 Australia (andre@dfe.net.au).

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Posted in Coastal & marine, Fauna & habitat, Integrating ecosystems & industries, New South Wales, Pest species, reconstruction, Standards, Techniques & methodology, Wetland

Operational planning and logistics – introducing fire into the landscape

Posted on 18 November 2015 by | Comments Off on Operational planning and logistics – introducing fire into the landscape

Robert Strauch

Eastern Suburbs Banksia Scrub (ESBS) is an Endangered Ecological Community that only exists in the eastern part of the Greater Sydney area – between North Head and La Perouse. From an original estimated area of 5300 hectares there’s only 146 hectares of this community left. From the 3% that’s actually left only 18% of that ESBS is on managed lands. A lot of it is in areas like golf courses, people’s backyards along coastal parts in the Sydney eastern suburbs and small pockets on Council reserves, most locations of it are quite sparse in area, with the North Head community being the largest portion in total area remaining.

In 2004, the key stakeholders developed a recovery plan for ESBS, with National Parks working with other land management agencies to try and protect and manage this community. One of the recommendations from the plan was high intensity burn at an 8-15 year rotation.

Fire and Rescue New South Wales (NSW) are re-introducing fire as a tool to restore ESBS at three sites: broad area burning at North Head, some windrow burning at La Perouse on the site of the NSW Golf Course and pile burning at Centennial Park in the Moore Park area. This involved three types of burns: an area burn, windrows and burn piles.

Fig 1. Broad area burning at North Head

Fig 1. Broad area burning at North Head

1. North Head

A burn was conducted at North Head, Sydney Harbour in early September 2012. This was done in collaboration with National Parks and Wildlife Service, the Sydney Harbour Federation Trust and also the North Head Sanctuary Foundation. Interestingly, the location of the fire is very close to the location Dr Geoff Lambert has identified as the site European people in Australia first recorded their observations of fire being used by Indigenous people on the 28th May 1788.

Methods and risk management. At North Head, three relatively small burns were conducted: third quarantine cemetery (0.8 ha), North Fort (1.5 ha0 and Blue Fish Drive (1.8 ha). These involved very high levels of operational logistics and operational planning, prior to waiting for the appropriate burn conditions.

(a) Public safety. Because of a history of fires getting out of control at North Head, precautions involved restricting public access to the headland, which meant confining all three burns to 1 day to minimise disruption. There was an overall incident controller, Superintendent Kel McNamara for the North Head complex, plus divisional commanders in charge of each of the burns. The divisional commanders essentially were running their individual burns managing their operations officers and resources required. From this we ended up with 10 firefighting appliances (trucks) and (including the incident management and logistical appliance) we had a total of 36 resources contributed by three agencies: Fire and Rescue NSW, National Parks and Wildlife Service and Rural Fire Service Pittwater-Warringah. With all of that we had 121 fire fighters for our very small sites. State Emergency Service assisted us with closing down walking trails and making sure people weren’t actually coming onto the headland. We had a fire truck (Flying Pumper) sitting there as if it was in a fire station, so if any spot fires occurred they could go and deal with the fire and we could still carry on with our prescribed burning that we were undertaking.

(b) On the day of the burns there were 400 kids on the headland, which was worrying. I tried to encourage them to go into Manly for the day but they wanted to stay on the headland for their planned activities at the Quarantine Station. Because of that I then had to go through steps in the local emergency management plan and arrange with Sydney Ferries to make sure there was a ferry ready and available in case we needed to evacuate the headland as we could only evacuate by water. Also we had to speak with Harbour Control in case the fire got away and we had to shut down the shipping channels coming into Sydney Harbour.

(c) Heritage protection. We obtained mitigation funding through the NDRP National Disaster Resilience Funds to do some mitigation work around North Head’s historical stone walls criss-crossing the headland. This involved some clearing along those walls to protect the historical significance of them and this clearing doubled to create a strategic fire advantage zone over the headland.

(d) Miscellaneous risks. Among the other things I had to deal with was underground ventilation. There’s historical war tunnels through North Head with ventilation intakes that I had to make sure were covered and insulated so we weren’t dragging smoke into the underground tunnels, increasing the carbon monoxide load down there. This was so if people walked in there after the burns they weren’t going to asphyxiate themselves. The bonus carry over from Defence was possible unexploded ordinance out on the headland. Furthermore, the Sydney Water treatment plant opposite the blue fish drive burn involves an above-ground storage tank of highly explosive biogas.

(e) We could only burn in certain seasons. The breeding seasons of the Endangered population of Long-nosed Bandicoot (Perameles nasuta) and also the penguins had to be considered. This also involved working in with studies of these that were being done by the University of New South Wales, researching the bandicoot’s pre and post-fire introduction. Then we had to put in a notification strategy. The weather window, given all the other constraints, was very narrow. We put out an email notification system where we were literally going to give people anything from 24 hours notice up to 48 hours notice to actually go ahead with the burn.

This high level of risk meant that I had to win the confidence of senior management of Fire and Rescue NSW to support the burn. We did get that support as well as support from all the other land managers, which was fantastic.

Burns themselves. In terms of the burns themselves, once the fire got into the burn area it developed to very good intensity. It was a very high fuel load situation and one interesting challenge was to try and stop the fire fighters from putting the fires out. The buildings were quite close and they were very small parcels of burns.

Ecological context. The burns that we did on North Head involved a range of experimental treatments that included burning, controlled thinning and untreated controls; with some sites fenced from rabbits, a study conducted by Dr Judy Lambert.

We burnt on a small scale to start with to see what type of regeneration we were going to get from broad area burning out on the headland. The regeneration that we’re getting out at North Head is outstanding. But the biggest problem that we have is the newly sprouted post fire vegetation degradation from rabbits and the bandicoots. So we suggest for any burning in ESBS, the advice is that it needs to be fenced post-burn to encourage the regeneration to thrive.

Fig 2. High biomass vegetation before burn, North Head

Fig 2. High biomass vegetation before burn, North Head

Fig 3. During burn at North Head

Fig 3. During burn at North Head

Fig 4. Water deliver from air, North Head

Fig 4. Water deliver from air, North Head

Fig 5. Mopping up after burn at North Head

Fig 5. Mopping up after burn at North Head

2. La Perouse

At the New South Wales golf course at La Perouse the dominant species, Coastal Tea Tree (Leptospermum laevigatum) was cut and dropped on the ground. They let it cure and then they come in and burn it in isolated pockets.  Burning on the golf course is a lot easier than North Head because there are far fewer risks to plan for and manage, and the eastern boundary is the Pacific Ocean. With this type of environment and preparation we can get extremely high intensity burns which are required for the ESBS. Once again the land managers fence the area to stop exposure to rabbits. At the La Perouse golf course site, we had arson this fire season so we had an additional 21 hectares of wildfire. We’ve put measures in place to monitor what introduced fire has done compared with what wildfire has done in the same vegetative area along Henry Head.

3. Centennial Park

Centennial Park, in the middle of Sydney, has an area of ESBS which is not even a hectare. The Park’s owners, the Centennial Park Trust, have been manually clearing weed from the ESBS, piling it and then conducting pile burns on the area, spreading the ash from that. Once again some really good regeneration has occurred there and the burn area is also fenced off to stop rabbits.

That’s our story of how Fire and Rescue NSW has been involved in broad area burning, windrow burning and pile burning, working with land managers for the recovery of Eastern Suburbs Banksia Scrub.

Acknowledgements: Fire and Rescue NSW acknowledge this project could not have happed without the collaboration of National Parks and Wildlife Service, the Sydney Harbour Federation Trust, North Head Sanctuary Foundation, Rural Fire Service Pittwater Warringah, Road and Maritime Services, NSW Police, Manly Council, Sydney Water, Sydney Ports, Sydney Ferries, Harbor Control, Department of Defence and many others.

Contact: Robert Strauch, Bushfire Officer – Metro East Command, Fire and Rescue NSW (Operational Capability, Specialised Operations, Bushfire Section – Level 1, 55 Dickson Avenue, Artarmon, NSW 2064. Tel: +61 2 9901 2445, +61 448 597 547; Email: E Robert.Strauch@fire.nsw.gov.au)

[This project summary is a precis of a talk presented to the Nature Conservation Council of NSW’s 10th Biennial Bushfire Conference, ‘Fire and Restoration: Working with Fire for Healthy Lands’ 26-27 May 2015. For full paper see: http://www.nature.org.au/healthy-ecosystems/bushfire-program/conferences/%5D

Fig 6. Windrows before the burn, La Perouse

Fig 6. Windrows before the burn, La Perouse

Fig 7. Burn La Perouse

Fig 7. Burn La Perouse

Fig 8. Mopping up after burn, La Perouse

Fig 8. Mopping up after burn, La Perouse

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Posted in Fire Ecology & Management, NCC 2015 Fire and restoration conference, NCC Fire and Restoration Conf 2015, New South Wales, Organisations, Pest species, Policy & legislation, Sclerophyll communities, Threatened species & communities, Urban ecosystems

The potential for Mozambique Tilapia to invade the Murray–Darling Basin and the likely impacts: a review of existing information

Posted on 30 January 2014 by | Comments Off on The potential for Mozambique Tilapia to invade the Murray–Darling Basin and the likely impacts: a review of existing information

Key words: Tilapia, pest fish, invasion risk, Native Fish Strategy

Threats and Impacts: Mozambique Tilapia (Oreochromis mossambicus) is a major pest fish species in Australia (Fig 1). A successful invader, it has managed to dominate natural waterways into which it has been introduced. It is not currently found in the Murray–Darling Basin; however, it has established thriving populations in catchments neighbouring the Basin. In some places, it is only a short distance from the northern headwaters. There is a high risk that this species will be introduced to the Basin.

Project aims and methods: Despite the high risk of introduction, prior to this project minimal work had been done to estimate the potential range Tilapia might occupy in the Basin, or to predict its possible impacts on natural, economic or social assets. This project set out to review available literature and assess likely impacts in an attempt to provide some information about these potential threats.

In order to estimate the potential range of Tilapia in the Murray–Darling Basin, this project set out to to:

  • predict the range in the Basin where Tilapia may survive through colder winter temperatures;
  • determine the length of the feasible breeding season (including the number of broods possible in that time) in different ranges; and,
  • determine the portion of the year in which Tilapia may feed and is therefore likely to have impacts on ecological processes through the food web.

This included:

  • estimating the lower temperature tolerance for Tilapia based on literature and survival rates of populations already infesting locations in Queensland;
  • identifying the minimum winter temperatures recorded at different locations throughout the Basin; and,
  • using the distribution of native fish with similar temperature tolerances to Tilapia as a surrogate.

Figure 1. Female Mozambique Tilapia carrying juveniles in her mouth (Photo courtesy of QLD DAFF)

Figure 1. Female Mozambique Tilapia carrying juveniles in her mouth (Photo courtesy of QLD DAFF)

Figure 2. male Mozambique Tilapia (Photo courtesy of QLD DAFF)

Figure 2. male Mozambique Tilapia (Photo courtesy of QLD DAFF)

Figure 3. Stunted Tilapia (male top, female bottom) mature at only a few centimetres in length, (Photo courtesy of QLD DAFF)

Figure 3. Stunted Tilapia (male top, female bottom) mature at only a few centimetres in length, (Photo courtesy of QLD DAFF)

Findings: Tilapia has a wide and varied diet and can occupy a diverse range of habitats, however, the one factor that appears to affect Tilapia is its vulnerability to cold temperatures. Based upon minimum temperature tolerated by Tilapia and the minimum water temperature data available, Tilapia have the potential to infest the northern Basin in Queensland and parts of New South Wales, through the western inland catchments of NSW and down to the Lower Lakes and lower Murray in South Australia. This equates to a distribution occupying approximately half of the MDB.

Tilapia is capable of sustaining reproducing populations under the conditions found in much of the MDB, as breeding and feeding can occur for significant portions of the year. In the northern parts of the Basin, and many southern parts, median water temperatures could see a breeding season of at least 3–6 months in duration with around 4–6 broods for each female in each breeding season.

Tilapia impacts have been recorded in a number of locations both in Australia and overseas. The key impacts recorded include major declines in commercial and traditional fisheries, fish extinctions, destruction of beds of aquatic plants) and declines in water quality. Some of the predicted direct impacts of Tilapia on the Murray–Darling Basin include:

  • direct predation by Tilapia;
  • competition for resources (food, habitat);
  • destruction of macrophytes and other aquatic plants used as breeding or nursery habitat by native species;
  • habitat disturbance;
  • transmission of diseases and parasites;
  • competitive exclusion of native fish from favourable habitat by tilapia’s aggressive behaviour;
  • increase of blue-green algal blooms (through resuspension of nutrients);
  • winter die-offs of tilapia (polluting waterways); and,
  • undermining river banks due to destruction of river plants and nesting behaviour.

Review of recent studies indicate that Tilapia consume juvenile native fish, including members of genera that occur in the Murray–Darling Basin, such as Rainbowfishes (Melanotaeniidae), Carp Gudgeons (Hypseleotris spp.), Hardyheads (Atherinidae), Bony Herring (Nematalosa erebi) and Glassfish (Ambassidae). It is possible that the potential preying of tilapia on native fish has been underestimated. 

Lessons learned and future directions: This project highlighted that invasion of the MDB by Tilapia could be disastrous for many (up to 18) native fish species of the MDB. Areas and species most at risk from Tilapia and the likely impacts if invasion occurred were identified. The study recommends a ‘prevention is better than cure’ approach with respect to Tilapia invasion and highlights education and awareness as a key factor. This review should be most pertinent in areas close to current distribution of wild tilapia populations (i.e. north-eastern MDB). 

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

Contacts: Dr Michael Hutchison, Queensland Department of Agriculture Fisheries and Forestry. Tel: + 61 7 3400 2037, Email: Michael.Hutchison@daff.qld.gov.au

Link:  http://www.mdba.gov.au/sites/default/files/pubs/Tilapia-report.pdf

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Posted in Fish, Freshwater aquatic, Pest animal issues & solutions, Pest species, Riparian & stream ecology