Category Archives: Pest species

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

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

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).

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

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

Assessing the susceptibility of previously untested basin fish species to Epizootic Haematopoietic Necrosis Virus (EHNV) and its epidemiology in the wild

Key words: Epizootic Haematopoietic Necrosis, EHN, disease, virus, native fish, Native Fish Strategy

Epizootic haematopoietic necrosis virus (EHNV) is a viral pathogen of international concern. The disease it causes is known from Redfin Perch (Perca fluviatilis) and farmed Rainbow Trout (Oncorhynchus mykiss) in some parts of the upper Murrumbidgee catchment and the lower Murray catchment in NSW, as well as from some parts of Victoria. Outbreaks have been recorded since 1985.

Despite its significance, very little was known about the natural distribution of EHNV in Australia or its real impact on native fish, as no formal surveys had ever been conducted. Although the susceptibility of native finfish species to EHNV had been suspected for some time, no work had been done to confirm this.

Objectives and methods: The objectives of this project were to identify the extent to which EHNV is a risk to native fish in the MDB and to provide scientific knowledge to aid in the development of effective management policy. The specific aims were to;

  1. validate earlier findings of susceptibility of native fish to EHNV,
  2. determine the susceptibility to infection by EHNV of a range of previously untested fish species found in the Basin,
  3. investigate the epidemiology of EHNV in wild populations of priority fish species and,
  4. develop a test to determine exposure of wild populations of priority fish species to EHNV.

Lab tests were undertaken using fish from candidate species separated into treatment and control groups, in which the former were exposed to the virus to identify native fish that are susceptible to EHNV (Fig 1). Subsequent analysis of 3622 tissue and 492 blood samples from fish collected from the field enabled the project team to look for instances of EHNV in the wild. Lastly, a new blood test was developed for Silver Perch (Bidyanus bidyanus), Murray Cod (Maccullochella peelii), Macquarie Perch (Macquaria australasica) and Redfin Perch, to detect antibodies resulting from immune responses to EHNV.

Figure 1, Experimentally infected Redfin Perch showing multiple white spots in the liver. Each spot is an area of dead tissue, where cells have become infected with and killed by EHNV.  (Photo courtesy Richard Whittington.)

Figure 1, Experimentally infected Redfin Perch showing multiple white spots in the liver. Each spot is an area of dead tissue, where cells have become infected with and killed by EHNV. (Photo courtesy Richard Whittington.)

Findings: It was concluded that EHNV is still present in the upper Murrumbidgee River catchment in the Murray-Darling Basin (MDB). During the study two separate outbreaks of disease due to EHNV occurred in juvenile Redfin Perch (at two locations) and a dead Redfin Perch infected with EHNV was detected (at one of the locations of an outbreak). EHNV appeared to be absent from Redfin Perch populations elsewhere in the MDB as there were no reports of disease outbreaks and neither virus nor antibodies against the virus were detected.

EHNV appeared to be absent from other species of fish in the MDB during the study period. Enough data were collected to be 95% confident that EHNV was present in <10% of the population of the following species: River Blackfish (Gadopsis marmoratus), Brown Trout (Salmo trutta), Mountain Galaxias (Galaxias olidus), Eastern Mosquitofish (Gambusia holbrookii), Murray Cod, Silver Perch, Southern Pygmy-perch (Nannoperca australis), Rainbow Trout and Redfin Perch.

The susceptibility of Silver Perch, Macquarie Perch and Eastern Mosquitofish to EHNV after exposure with water was confirmed. Two new susceptible species were identified: Murray-Darling Rainbowfish (Melanotaenia fluviatilis) and Freshwater Catfish (Tandanus tandanus). Species which became infected with EHNV following exposure via water, and in which some individuals survived and appeared to carry the live virus were Silver Perch, Eastern Mosquitofish, and Redfin Perch. Species with resistance to EHNV following exposure via water were Murray Cod, Golden Perch, Un-specked Hardyhead (Craterocephalus stercusmuscarum), Carp Gudgeon (Hypseleotris spp), Southern Purple-spotted Gudgeon (Mogurnda adspersa), Trout Cod and Southern Pygmy-perch.

Redfin Perch generally were highly susceptible to EHNV, but there appeared to be differences in susceptibility between populations. Fish from Blowering Dam in the known endemic region appeared to have a greater degree of resistance than others.

A new blood test was developed during this project to detect antibodies resulting from immune responses in fish against EHNV. A specific test was developed for Silver Perch, Murray Cod, Macquarie Perch and Redfin Perch with results suggesting that the blood test has application in field surveys for EHNV.

Lessons learned and future directions: The findings of this study reinforce a view that EHNV is a factor detrimental to native fish populations in the MDB and policies to reduce the risk of exposure to the disease in the MBD are justifiable and necessary to protect native fish populations.

The blood test developed in this study is versatile and opens up a new range of options to study the health of fish in the MDB. It has application in a much wider range of species, and it can be adapted to detect antibodies against many other pathogens. An advantage of the blood test is that it can reveal past exposure of a population to EHNV.

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy and undertaken by a collaborative team from the University of Sydney and NSW DPI.

Contacts: Professor Richard Whittington, University of Sydney, Tel +61 2 9351 1619, Email: richard.whittington@sydney.edu.au.

Link: http://www.finterest.com.au/wp-content/uploads/2013/07/MD743%20EHNV.pdf

Assessing the recovery of fish communities following removal of the introduced Eastern Gambusia

Key words:  Gambusia holbrooki, pest species control, native fish recovery, Native Fish Strategy.

Threats and Impacts: Alien fish species have been recognised as one of eight major threats to native fish in the Murray–Darling Basin (MDB), and the control of these species is one of the key drivers of the Native Fish Strategy. There is growing evidence of detrimental impacts of Eastern Gambusia (Gambusia holbrooki) on native fish fauna globally, and this species has been identified as potentially one of the key alien species contributing to the decline of a number of native fish within the MDB, where it is widespread (Figs 1 and 2). The ecological impacts of the Eastern Gambusia in the MDB remain uncertain and this project addressed these research needs by integrating surveys and experimental work in natural billabong systems throughout the MDB.

Broad aim and specific objectives: The specific objectives of the project were to:

1. Review current knowledge of the impacts of Eastern Gambusia on native fishes of the MDB.

2. Provide information on the response of native fish communities following the reduction of Eastern Gambusia populations.

3. Provide a framework to evaluate the feasibility and effectiveness of such control actions and form a template for evaluating control options for other alien fishes across the MDB.

Figure 1: Mature female Eastern Gambusia (photo courtesy of Tarmo Raadik)

Figure 1: Mature female Eastern Gambusia (photo courtesy of Tarmo Raadik)

Figure 2: High density of Eastern Gambusia in a shallow backwater environment (Photo courtesy of Tarmo Raadik)

Figure 2: High density of Eastern Gambusia in a shallow backwater environment (Photo courtesy of Tarmo Raadik)

 

Methods: The project was divided into four phases. The first phase involved a review of current knowledge of the impacts of Eastern Gambusia on native fishes of the MDB. The second phase involved a broad-scale, cross-sectional study of wetland fish communities to develop hypotheses about the effect of Eastern Gambusia on native fish communities in these enclosed systems. The third phase was a field trial of Eastern Gambusia control in small isolated billabongs, to test the hypotheses through density manipulation experiments and to provide information on control options and Eastern Gambusia population dynamics. The fourth phase identified strategies to maximise the level of improvement to the native fish community through Eastern Gambusia control given a fixed budget (benefit maximisation), and to minimise the cost of achieving a defined significant improvement in the native fish community (cost minimisation). Finally, the project provided a template for evaluating control options for other alien fishes across the MDB.

Findings: The review of literature exploring impacts of Eastern Gambusia on native fishes of the MDB identified that 16 of 37 native species have major habitat or diet (or both) overlaps with Eastern Gambusia. The most significant overlaps were with small-bodied species e.g. Glassfish (Ambassidae), Pygmy-perches (Nannopercidae), Rainbowfishes (Melanotaeniidae), Hardyheads (Atherinidae), Gudgeons (Eleotridae) and Smelt (Retropinnidae). The review therefore concluded that Eastern Gambusia is likely to have contributed to the decline (in distribution and/or abundance) of the Olive Perchlet (Ambassis agassizii), Southern Pygmy-perch (Nannoperca australis), Murray-Darling Rainbowfish (Melanotaenia fluviatilis) and Purple-spotted Gudgeon (Mogurnda adspersa).

An assessment of wetland communities throughout the mid-Murray region of the MDB found that Carp Gudgeon (Hypseleotris spp.) and Eastern Gambusia were the dominant species in both abundance and distribution. The results of the survey suggest that Eastern Gambusia do not have a negative influence on abundances of the more common native species (e.g. Carp Gudgeon and Flat-headed Gudgeon (Philypnodon grandiceps) most likely due to the generalist nature of such species enabling co-existence. Gambusia were found to impact on the abundance of juveniles of several native species, and on their general health by ‘fin nipping’

Several small isolated billabongs had Eastern Gambusia removed to observe how native fish would respond. During this trial, astonishingly, a few individual Eastern Gambusia were able to re-establish populations of thousands within three or four months. Most importantly, the results of the removal trial indicate that reductions of Eastern Gambusia abundances will result in some improvements to small-bodied native fish populations, and these effects may be enhanced within billabongs without complex habitat (making Gambusia easier to catch and remove), and containing native species with quite specific diets.

In examining the cost-effectiveness and logistics of Eastern Gambusia removal, this study presents a strategy to determine the feasibility of removal for different scenarios and concluded that the highest benefits per dollar invested were for habitats with low frequency of connection to other Eastern Gambusia populations, low structural complexity and of high ecological value.

Lessons learned and future directions: This project provides fundamental ecological information necessary for management of Eastern Gambusia. This project provides managers with a decision making tool to assess the cost benefit of Eastern Gambusia removal for a range of habitat scenarios. This will result in better targeted action of controlling this pest species and maximise benefits to native fish populations. This project will raise awareness of the impacts of Eastern Gambusia on native fish and what benefits may be obtained for native fish following Eastern Gambusia removal.

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

Contacts: Zeb Tonkin, South Australian Research and Development Institute. Tel: + 61 3 9450 8600, Email: zeb.tonkin@depi.vic.gov.au.