Category Archives: Techniques & methodology

Ku-ring-gai Flying-fox Reserve Habitat Restoration Project at Gordon, 2000 – 2019 UPDATE of EMR feature

Nancy Pallin

[Update to EMR feature –  Pallin, Nancy (2001) Ku-ring-gai Flying-fox Reserve Habitat restoration project, 15 years on.  Ecological Management & Restoration 1:1, 10-20. https://onlinelibrary.wiley.com/doi/10.1046/j.1442-8903.2000.00003.x]

Key words:         bush regeneration, community engagement, wallaby browsing, heat events, climate change

Figure 1. Habitat restoration areas at Ku-ring-gai Flying-fox Reserve within the urban area of Gordon, showing areas treated during the various phases of the project. Post-2000 works included follow up in all zones, the new acquisition area, the pile burn site, the ecological hot burn site and sites where vines have been targeted. (Map provided by Ku-ring-gai Council.)

Introduction. The aim of this habitat restoration project remains to provide self-perpetuating indigenous roosting habitat for Grey-headed Flying-fox (Pteropus poliocephalus) located at Ku-ring-gai Flying-fox Reserve in Gordon, NSW Australia (Fig 1).  The secondary aim was to retain the diversity of fauna and flora within the Flying-fox Reserve managed by Ku-ring-gai Council. Prior to works, weed vines and the activity of flying-foxes in the trees had damaged the canopy trees while dense weed beneath prevented germination and growth of replacement trees.  Without intervention the forest was unable to recover.  Natural regeneration was assisted by works carried out by Bushcare volunteers and Council’s contract bush regeneration team.  The work involved weed removal, pile burns and planting of additional canopy trees including Sydney Bluegum (Eucalyptus saligna), which was expected to cope better with the increased nutrients brought in by flying-foxes.

Figure 2. The changing extent of the Grey-headed Flying-fox camp from the start of the project, including updates since 2000. (Data provided by KBCS and Ku-ring-gai Council)

Significant changes have occurred for flying-foxes and in the Reserve in the last 20 years.

In 2001 Grey-headed Flying-fox was added to the threatened species lists, of both NSW and Commonwealth legislation, in the Vulnerable category.  Monthly monitoring of the number of flying-foxes occupying the Reserve  has continued monthly since 1994 and, along with mapping of the extent of the camp, is recorded on Ku-ring-gai Council’s Geographical Information System. Quarterly population estimates contribute to the National Monitoring Program to estimate the population of Grey-headed Flying-fox.  In terms of results of the monitoring, the trend in the fly-out counts at Gordon shows a slight decline.  Since the extreme weather event in 2010, more camps have formed in the Sydney basin in response to declining food resources.

In 2007, prompted by Ku-ring-gai Bat Conservation Society (KBCS), the size of the Reserve was increased by 4.3 ha by NSW Government acquisition and transfer to Council of privately owned bushland. The Voluntary Conservation Agreement that had previously established over the whole reserve in 1998 was then extended to cover the new area.   These conservation measures have avoided new development projecting into the valley.

From 2009 Grey-headed Flying-fox again shifted their camp northwards into a narrow gully between houses (Fig 2).  This led to human-wildlife conflict over noise and smell especially during the mating season. Council responded by updating the Reserve Management Plan to increase focus on the needs of adjoining residents.  Council removed and trimmed some trees which were very close to houses. In 2018 the NSW Government, through Local Governments, provided grants for home retrofitting such as double glazing, to help residents live more comfortably near flying-fox camps.

Heat stress has caused flying-fox deaths in the Reserve on five days since 2002. Deaths (358) recorded in 2013, almost all were juveniles of that year.  KBCS installed a weather station (Davis Instruments Vantage Pro Plus, connected through a Davis Vantage Connect 3G system) and data loggers to provide continuous recording of temperature and humidity within the camp and along Stoney Creek.  The station updates every 15 minutes and gives accurate information on conditions actually being experienced in the camp by the flying-foxes. The data is publicly available http://sydneybats.org.au/ku-ring-gai-flying-fox-reserve/weather-in-the-reserve/Following advice on the location and area of flying-fox roosting habitat and refuge areas on days of extremely high temperatures (Fig 3.) by specialist biologist Dr Peggy Eby, Council adopted the Ku-ring-gai Flying-fox Reserve 10 Year Management and Roosting Habitat Plan in 2018.  Restoration efforts are now focused on improving habitat along the lower valley slopes to encourage flying-foxes to move away from residential property and to increase their resilience to heat events which are predicted to increase with climate change.

Figure 3. Map showing the general distribution of flying-foxes during heat events, as well as the location of exclosures. (Map provided by Ku-ring-gai Council)

Further works undertaken.  By 2000 native ground covers and shrubs were replacing the weeds that had been removed by the regeneration teams and Bushcare volunteers.  However, from 2004, browsing by the Swamp Wallaby (Wallabia bicolor) was preventing growth of young trees and shrubs.  Bushcare volunteers, supported by KBCS and Council responded by building tree cages made from plastic-mesh and wooden stakes. Reinforcing-steel rods replaced wooden stakes in 2008.   From 2011, the Bushcare volunteers experimented with building wallaby exclosures, to allow patches of shrubs and groundcovers to recover between trees (Figs 3 and 4).  Nineteen wallaby exclosures have been built. These range in size from 7m2 to 225m2 with a total area of 846m2.   Wire fencing panels (Mallee Mesh Sapling Guard 1200 x 1500mm) replaced plastic mesh in 2018.  Silt fence is used on the lower 0.5m to prevent reptiles being trapped and horizontally to deter Brush Turkey (‎Alectura lathami) from digging under the fence.

The wallaby exclosures have also provided an opportunity to improve moisture retention at ground level to help protect the Grey-headed Flying-fox during heat events.  While weed is controlled in the exclosures south of Stoney Creek, those north of the creek retain Trad and privets, consistent with the 10 Year Management and Roosting Habitat Plan.

Madeira Vine (Anredera cordifolia) remained a threat to canopy trees along Stoney Creek for some years after 2000, despite early treatments.  The contract bush regen team employed sInce 2010 targeted 21 Madiera Vine incursions.

A very hot ecological burn was undertaken in 2017 by Council in order to stimulate germination of soil stored seed and regenerate the Plant Community Type (PCT) – Smooth-barked Apple-Turpentine-Blackbutt tall open forest on enriched sandstone slopes and gullies of the Sydney region (PCT 1841).  This area was subsequently fenced. The contract bush regeneration team was also employed for this work to maintain and monitor the regeneration in the eco-burn area (720 hours per year for both the fire and Madiera Vine combined).

Figure 4. Exclusion fence construction method. Pictured are Bushcare volunteers, Jill Green and Pierre Vignal. (Photo N Pallin).

Figure 5. Natural regeneration in 2018 in (unburnt) exclosure S-6 (including germination of Turpentines). (Photo N. Pallin)

Further results to date. The original canopy trees in Phase 1 and Phase 2 (1987 -1997) areas have recovered and canopy gaps are now mostly closed. Circumference at breast height measurements were taken for seven planted Sydney Blue gum trees.  These ranged from 710 to 1410mm with estimated canopy spread from 2 to 6m.  While original Turpentine (Syncarpia glomulifera) had circumferences from 1070 and 2350mm with canopy spread estimated between 5and 8m, those planted or naturally germinated now have circumference measurements between 420 and 980mm with canopy spread estimated from 1.5 to 3m.  A Red Ash (Alphitonia excelsa) which naturally germinated after initial clearing of weeds now has a circumference of 1250mm with a canopy spread of 5m.  Also three Pigeonberry Ash (Elaeocarpus kirtonii) have circumference from 265 to 405mm with small canopies of 1 to 2m as they are under the canopies of large, old Turpentines.  As predicted by Robin Buchanan in 1985 few Blackbutt (Eucalyptus pilularis) juveniles survived while the original large old trees have recovered and the Sydney Bluegum trees have thrived.

In the Phase 3 (1998 – 2000) area south of Stoney Creek the planted Sydney Blue Gum now have circumferences measuring between 368 and 743 (n7) with canopy spread between 2 and 6 m.  in this area the original large trees have girths between 1125 and 1770mm (n7) whereas trees which either germinated naturally or were planted now range from 130 to 678mm (n12).  These measurement samples show that it takes many decades for trees to reach their full size and be able to support a flying-fox camp.

Wallaby exclosures constructed since 2013 south of Stoney Creek contain both planted and regenerated species.  Eight tree species, 11 midstorey species, 27 understorey species and eight vines have naturally regenerated.  Turpentines grew slowly, reaching 1.5m in 4 years.  Blackbutts thrived initially but have since died. In exclosures north of the creek,  weeds including Large-leaved Privet,  Ligustrum lucidum,  Small-leaved privet,  L. sinense,  Lantana, Lantana camara,  and Trad, Tradescantia fluminensis) have been allow to persist and develop to maximise ground moisture levels for flying-foxes during heat events. Outside the exclosures, as wallabies have grazed and browsed natives, the forest has gradually lost its lower structural layers, a difference very evident in Fig 6.

Figure 6. Visible difference in density and height of ground cover north and south of Stoney creek. (Photo P. Vignal)

Coachwood (Ceratopetalum apetalum) were densely planted in a 3 x 15m exclosure under the canopies of mature Coachwood next to Stoney Creek in 2015. In 4 years they have reached 1.5m.  In this moist site native groundcovers are developing a dense, moist ground cover.

Madiera Vine, the highest-threat weed, is now largely confined to degraded edges of the reserve, where strategic consolidation is being implemented with a view to total eradication.

In the hot burn area, which was both fenced and weeded, recruitment has been outstanding. One 20 x 20m quadrat recorded 58 native species regenerating where previously 16 main weed species and only 6 native species were present above ground. A total of 20 saplings and 43 seedlings of canopy species including Eucalyptus spp., Turpentine and Coachwood were recorded in this quadrat where the treatment involved weed removal, burning and fencing  (S. Brown, Ku-ring-gai Council, July 2019, unpublished data).  Unfortunately, however, the timing and location of the burn did not take into account its impact on the flying-fox camp and there was some damage to existing canopy trees. It will be many years before the canopy trees, which are regenerating, will be strong enough to support flying-foxes.

Monitoring from the weather station and data loggers has shown that close to Stoney Creek on a hot day it is typically 2-3° C cooler, and 5-10% higher in humidity, than in the current camp area (pers. comm. Tim Pearson). During heat events the flying-foxes move to this cooler and moister zone, increasing their chances of survival.

Fauna observed other than flying-foxes includes a pair of Wedge-tail Eagle ( Aquila audax plus their juvenile, a nesting Grey Goshawk (Accipiter novaehollandiae) and a Pacific Baza (Aviceda subcristata).  Powerful Owl (Ninox strenua) individuals continue to use the valley. The presence of raptors and owls indicate that the ecosystem processes appear to be functional. Despite the decline of the shrub layer outside fenced areas, the same range of small bird species (as seen prior to 2000) are still seen including migrants such as Rufous Fantail ( Rhipidura rufifrons) which prefers dense, shady vegetation. The first sighting of a Noisy Pitta (Pitta versicolor) was in 2014.  Long-nosed Bandicoot (Perameles nasuta) individuals appear and disappear, while Swamp Wallaby remains plentiful.

Lessons learned and future directions. Climate change is an increasing threat to Pteropus species. On the advice of Dr Eby, Flying-fox Consultant, Council, KBCS and Bushcare Volunteers agreed to retain all vegetation including weeds such as Large-leaved Privet and Small-leaved Privet, patches of the shrub Ochna (Ochna serrulata) and Trad as a moist ground cover in the camp area and areas used by the flying-foxes during heat events.

Building cheap, lightweight fencing can be effective against wallaby impacts, provided it is regularly inspected and repaired after damage caused by falling branches. This style of fencing has the additional advantage of being removable and reusable.  It has been proposed that, to provide understory vegetation to fuel future burns in parts of the reserve away from the flying-fox camp, further such temporary fencing could be installed.

Ku-ring-gai Council has commenced a  program to install permanent monitoring points to annually record changes in the vegetation, consistent with the state-based  Biodiversity Assessment Method.

Stakeholders and Funding bodies. Members of KBCS make donations, volunteer for monthly flyout counts, Bushcare and present educational events with live flying-foxes. KBCS hosts the website www.sydneybats.org.au. Ku-ring-gai Council which is responsible for the Reserve has been active in improving management to benefit both residents and flying-foxes.  Ku-ring-gai Environmental Levy Grants to KBCS have contributed substantially to purchase of fencing materials and the weather station. http://www.kmc.nsw.gov.au/About_Ku-ring-gai/Land_and_surrounds/Local_wildlife/Native_species_profiles/Grey-headed_flying-fox

Thank you to Jacob Sife and Chelsea Hankin at Ku-ring-gai Council for preparing the maps and to volunteer Pierre Vignal for assistance with tree measurements, downloading data loggers and a photo.  Researcher,  Tim Pearson installed the weather station.

Contact information. Nancy Pallin, Management Committee member, Ku-ring-gai Bat Conservation Society Inc.  PO Box 607, Gordon 2072  Tel 61 418748109. Email:  pallinnancy@gmail.com

Ecological restoration and rehabilitation at Sydney Olympic Park – UPDATE to EMR feature

Jennifer O’Meara and Kerry Darcovich

[Update to EMR feature – O’Meara, Jennifer and Kerry Darcovich (2015) Twelve years on: Ecological restoration and rehabilitation at Sydney Olympic Park, Ecological Management & Restoration, 16:1, 14-28. https://onlinelibrary.wiley.com/doi/10.1111/emr.12150 ]

Keywords: Environmental management, ecological management, threatened species, Habitat management , woodland birds, Green and Golden Bell Frog

Introduction. The 2015 EMR feature described ecological restoration and management works at Sydney Olympic Park, a large urban park containing both remnant and constructed landscapes that underwent significant restoration in preparation for the 2000 Olympic Games. Sydney Olympic Park supports a rich natural environment that includes over 250 native animal species, over 400 native plant species and three endangered ecological communities.  The high ecological values of the Park have resulted in 304 hectares (nearly half of the Park) being zoned under NSW planning legislation for environmental conservation and management.  Key habitats include estuarine and freshwater wetlands, remnant eucalypt forest, saltmarsh meadows and woodland bird habitats.

The Park’s biodiversity is of high conservation significance, and makes a significant contribution to the social and economic values of the Park.  The Park’s natural environments enrich visitor experience, provide a living classroom for environmental education programs, and attract businesses and residents seeking proximity to nature. This project began in 2000 when management transferred from a construction phase after the Sydney Olympic Games to an active management phase and is supported by an extensive long term ecological monitoring program. This update summarises new works and outcomes since 2016.

Further works undertaken. The introduction of new ecological infrastructure for frog habitat targets threatening processes of predation by introduced fish and increasing water availability.  Fish-proof fences have been introduced to wetlands where the predatory fish Gambusia (Gambusia holbrooki) is present in Green and Golden Bell Frog (Litoria aurea) habitat (Fig 1). The fences are placed around ponds or pond clusters and then the pond is dried out and refilled with fish-free water. Constructed of sediment fences 600mm high and embedded in the ground, these fences stretch to a maximum of 200m and have successfully restricted the fish from ponds for more than three years.

Figure 1.  Gambusia fence

In order to reduce the impact of bird predation on tadpoles in key breeding ponds, bird netting secured by wire cables to the ground and supported by hoops has been introduced.  The netting is also used as a response to the sighting of Green and Golden Bell Frog tadpoles in ponds with Sydney Olympic Park staff deploying temporary netting where successful breeding has occurred. Netting is left on the pond until all metamorphs have dispersed from the pond then removed.

Restoration of the water-holding capacity and connectivity of bell frog habitat in the Brickpit and Kronos Hill has been improved with temporary ponds being created with tarps (Fig 2). The aim is twofold – to extend the number of predator-free, drought refuges, important for adult female frogs and metamorphs and to ensure frog corridors maintain connectivity.  More than 10 tarp ponds have been created and have an expected life span of 3-6 years and are very budget friendly. Annual monitoring has shown a remarkable uptake of these ponds by the Green and Golden Bell Frog.

Figure 2.  Tarp pond with netting

Further results to date. The Parks ecological monitoring program is ongoing and now entering the 16th consecutive year for birds, 15th for reptiles and 21 years for the Green and Golden Bell Frog. In 2018-19 the fourth woodland bird survey was completed, a four yearly assessment of the status of woodland birds and vegetation management at Sydney Olympic Park. Fifteen quadrats are surveyed over the spring and autumn seasons to measure bird communities which is then compared to change in vegetation structure. Results show that small birds were strongly, positively correlated with shrub cover, but strongly negatively correlated with tree cover and Noisy Miner (Manorina melanocephala).  Since 2006, Sydney Olympic Park Authority has implemented a habitat modification program aimed at increasing the structural diversity and complexity of key areas of the Park to support woodland birds. The program seeks to build connectivity between key woodland bird habitats with the form of habitat enhancement varying depending on site characteristics. The survey shows that this program is successfully creating suitable habitat for this group of birds.

With the prospect of greater demands by the public to access the Park at all hours (see below), Sydney Olympic Park staff have recently collected baseline light level readings from across the Park to inform decision making.  Data on lux levels and light source was collected from over 160 sites ranging from car parks to mangrove creeks. The main drive of the survey was to collect information on light spill into sensitive habitat areas where darkness is a key ecological feature. The survey led to a review of lighting and identification of where lights could be switched off or timed to decrease light impacts. The findings will also inform future planning for illumination within the Park.

Lessons learned and future directions. Sydney Olympic Park is part of a rapidly densifying area with the 30,000 residents currently located within a 3km radius forecast to increase to approximately 100,000 in ten years. Due to the density of housing, Sydney Olympic Park will be/is already the local park for this community, leading to increasing demand for recreation and access to the Parklands. This presents great opportunities for more people to connect with nature and to incorporate community education and sustainability into Park programs.  A new program known as Park Care has been launched recently and currently rolls out community clean up and revegetation activities.

The flipside of this rapid population increase is increasing risk of disturbance to ecologically sensitive areas which needs to be considered and mitigated carefully as the Park continues to evolve. Ensuring the Park is able to sustainably meet this demand is a focus for management now and into the future. New habitat management plans for ecologically sensitive areas of the Park are being developed to better-guide biodiversity conservation on a precinct level. Ongoing ecological management works, and managing the impacts of human disturbance, will be essential to conserving the ecological values of the Park.

Contact. Jennifer O’Meara, Parklands Ecologist, Sydney Olympic Park Authority, 5 Olympic Boulevard, Sydney Olympic Park 2127 NSW, Australia. Email: Jenny.omeara@sopa.nsw.gov.au

Developments in Big Scrub Rainforest Restoration: UPDATE of EMR feature

Tony Parkes, Mark Dunphy, Georgina Jones and Shannon Greenfields

[Update of EMR feature article: Parkes, Tony, Mike Delaney, Mark Dunphy, Ralph Woodford, Hank Bower, Sue Bower, Darren Bailey, Rosemary Joseph, John Nagle, Tim Roberts, Stephanie Lymburner, Jen Ford and Tein McDonald (2012) Big Scrub: A cleared landscape in transition back to forest? Ecological Management & Restoration 12:3, 212-223. https://doi.org/10.1111/emr.12008]

Key words: Lowland Subtropical Rainforest, ecological restoration, seed production, landholder action, corridors

Figure 1a. Rainforest regenerators undertake camphor injection, leaving bare trees standing creating light and an opportunity for seed in the soil to naturally regenerate. (Photo © Envite Environment)

Figure 1b Aerial photo showing camphor conversion by injection
(Photo © Big Scrub Regeneration Pty. Ltd.)

Introduction. The Big Scrub, on the NSW north coast, was once the largest tract of Lowland Subtropical Rainforest (LSR) in Australia. It was reduced to less than 1% of its original extent by he end of hte 19th century after clearing for agriculture. Big Scrub Landcare (BSL) is a non-profit organisation dedicated to improving the long-term ecological functionality of what remains of this critically endangered ecosystem –  lowland subtropical rainforest.  Our 2012 EMR feature reported on remnant restoration and revegetation works overseen by BSL to 2012. At that time, 68 remnants were identified as significantly affected from the impacts of environmental degradation including weed invasion and cattle access. These remnants had been undergoing treatments, with 20 substantially recovered and on a ‘maintenance’ regime.  Approximately 900,000 trees had been planted to establish 250 ha of young diverse well-structured rainforest.  A comparatively small area of forest dominated by the highly invasive exotic, Camphor Laurel (Cinnamomum camphora) (Camphor), which  has colonised much of the Big Scrub landscape had been converted to early phase LSR by skilled removal of a range of weeds and facilitating natural regeneration. 

Progress since 2012. Substantial progress in restoring critically endangered lowland subtropical rainforest in the Big Scrub has been achieved over the past seven years in the following areas.

  • Assisted regeneration of remnants has continued and become more focused
  • Re-establishment of LSR through plantings has expanded
  • Camphor conversion has developed in scale and techniques
  • Greater security of funding has been achieved
  • Community engagement has greatly improved and expanded
  • Genome science is being applied to produce seed with optimal genetic diversity for rainforest restoration.

Assisted regeneration of remnants. This work continues to be the major focus of on-ground restoration work. About 2000 regenerator days (9 years Full Time Equivalent) of work has been undertaken in 45 remnants. BSL’s remnant restoration program has become more strategic, with more focus on Very High Conservation Value (VHCV) remnants, particularly those in the NSW National Parks Estate, including the VHCV sites in Nightcap National Park (NP) including Big Scrub Flora Reserve, Minyon Falls and Boomerang Falls; Andrew Johnston’s Scrub NR; Snow’s Gully Nature Reserve (NR); Boatharbour NR; Victoria Park NR and Davis Scrub NR, plus the Booyong Flora Reserve. Rehabilitation work at these sites is prioritised in the major new four-year Conservation Co-funding project funded jointly by BSL and the NSW government’s Saving our Species program. Big Scrub Foundation (BSF) funding has enabled BSL to continue maintenance work in remnants that have reached or are approaching the maintenance stage.

Monitoring outcomes has become more rigorous and has demonstrated ongoing improvements in vegetation structure, with decreasing levels of weed invasion and improvements in native species cover.

BSL’s partner Envite Environment, with some assistance from BSL, is creating an important linkage between Nightcap NP and Goonengerry NP by the restoration of rainforest through the progressive removal of weeds that had dominated the 80 ha Wompoo/Wanganui corridor between these two NPs.

 Re-establishment of rainforest by planting. The area of LSR is being re-established by planting on cleared land has also continued to expand.   In the last 7 years  more than 0.5 million rainforest trees have been planted in the Big Scrub region, contributing to the restoration of another 175 ha of LSR, expanding total area of re-established rainforest by another 13%. While landscape-scale landholder driven work is inevitably opportunistic rather than strategic, the establishment of new patches of LSR enhance valuable stepping-stone corridors across the Big Scrub. Since 2012 the number of regenerators working fulltime in the Big Scrub region has increased by approximately 50%.  Another trend that has strengthened in the last 7 years is that larger plantings are now being carried out by well-resourced landowners. This is accounting for about 40% of the annual plantings. Offsets for residential development account for another 40% of trees planted. The remaining 20% is made up by small landowners, cabinet timber plantations, large-scale landscaping, and other planting of Big Scrub species. This is a significant change from the more dominant grant-based small landowner/Landcare group plantings prior to 2012.

 Camphor conversion. Larger areas of Camphor forest are being converted to rainforest, with project areas increasing substantially from less than a hectare to ten and twenty hectares. BSL estimates that more than 150 ha of Camphor forest are currently under conversion. Some landowners underake camphor injection which leaves bare trees standing, creating light and an opportunity for existing native seedlings and seed in the soil (or seed dropped by perching birds) to naturally regenerate (Fig 1). Others are choosing the more expensive option of physically removing the Camphor trees and carefully leaving the rainforest regrowth (Fig 2).  Improved techniques and landholder capacity building continue to progress and camphor conversion is now a significant component of rainforest restoration.

BSL alone is facilitating the conversion of almost 40 ha of Camphor forest to LSR funded by two 3-year grants from the NSW Environmental Trust, together with contributions from the 19 landholders involved in these projects. The ecological outcomes being achieved are significant and less costly than revegetation via plantings.

Figure 2a. Camphor forest under conversion using heavy machinery leaving rainforest regrowth intact (Photo © Big Scrub Landcare)

Figure 2b. Aerial photo showing camphor conversion by removal
(Photo © Big Scrub Landcare)

Greater security of funding. Australian Government funding for biodiversity conservation is at a very low level. Competition for existing NSW state government funding is increasing. BSL therefore has continued to  develop new strategies for fund raising to ensure continuity of its long-term program for the ecological restoration of critically endangered LSR in the Big Scrub and elsewhere. Ongoing funding of at least $150,000 annually is needed to ensure the great progress made  over the past 20 years in rehabilitating remnants is  maintained and expanded to new areas of large remnants. These funds finance weed control and monitoring; weeds will always be a part of the landscape and an ongoing threat to our rainforest remnants.

Establishment of the Big Scrub Foundation in 2016 was a major development in BSL’s fund raising strategy. The Foundation received a donation of AUD $1M to establish a permanent endowment fund that is professionally invested to generate annual income that helps finance BSL’s remnant care program and its other activities. Generous donors are also enabling the Foundation to help finance the Science Saving Rainforest Program.

Figure 3a. Australian gardening celebrity Costa Gregoriou at a Big Scrub community tree planting (part of the 17th annual Big Scrub Rainforest Day) in 2015 (Photo © Big Scrub Landcare)

Figure 3b. Founder of the Australian Greens political party Bob Brown and Dr. Tony Parkes at the 18th annual Big Scrub Rainforest Day in 2016. (Photo © Big Scrub Landcare)

Community engagement. The  Big Scrub Rainforest Day continues to be BSL’s  major annual community engagement event, with the total number of attendees estimated to have exceeded 12,000 over the past 7 years; the 2016 day alone attracted more than 4000 people (Fig 3). Every second year the event is held at Rocky Creek Dam.  A new multi-event format involving many other organisations has been introduced on alternate years.

BSL’s Rainforest Restoration Manual has been updated in the recently published third edition and continues to inform and educate landowners, planners and practitioners.

BSL in partnership with Rous County Council produced a highly-commended book on the social and ecological values of the Big Scrub that has sold over 1000 copies. BSL’s website has had a major upgrade: its Facebook page is updated weekly; its e-newsletter is published every two months. BSL’s greatly improved use of social media is helping to raise its profile and contribute to generating donations from the community, local businesses and philanthropic organisations to fund its growing community education and engagement work and other activities.

Science saving rainforests program. BSL, the Royal Botanic Gardens Sydney, the BSF and their partners have commenced an internationally innovative program to apply the latest DNA sequencing and genome science to establish plantations to produce seed of key species with optimal genetic diversity for the ecological restoration of critically endangered lowland subtropical rainforest. This program will for the first time address the threat posed by fragmentation and isolation resulting from the extreme clearing of Australia’s LSR, which is estimated to have resulted in the destruction of 94% of this richly biodiverse Gondwana-descended rainforest.

Many  key  LSR species are trapped in small populations in  isolated remnants  that  lack the genetic diversity needed to adapt and survive in the long term, particularly faced with climate change Necessary  genetic diversity is also lacking in many key species in the 500 ha of planted and regrowth rainforest. The first stage of the program, already underway, involves collecting leaf samples from approximately 200 individual old growth trees in 35 remnant populations across the ranges of 19 key structural species of the ‘original’ forest. DNA will be extracted from the leaf samples of each species and sequenced. The  latest genome science will be applied to select the 20 individual trees of each species that will be cloned to provide planting stock with optimal genetic diversity for the establishment of a living seed bank in the form of a plantation that will produce seed  for use in restoration plantings. As the individual trees in the restoration plantings reproduce, seed with appropriate genetic diversity and fitness will be distributed across the landscape. The project focuses on key structural species and thus helping the survival of Australia’s critically endangered Lowland Subtropical Rainforest in the long term.

Lessons learned and current and future directions. A key lesson learned some five years ago was that BSL had grown to the point where volunteers could no longer manage the organisation effectively. BSL took a major step forward in 2015 by engaging a part-time Manager, contributing to BSL’s continuing success by expanding the scope, scale and effectiveness of its community engagement activities and improving its day to day management.

The principal lesson learned from BSL’s on-ground restoration program is to focus on rehabilitation of remnants and not to take on large planting projects, but rather support numerous partnered community tree planting events. Large grant-funded multi-site tree planting projects are too difficult to manage and to ensure landholders carry out the necessary maintenance in the medium to long term.

Acknowledgements.  BSL acknowledges our institutional Partners and receipt of funding from the NSW government’s Saving our Species program, NSW Environmental Trust and Big Scrub Foundation.

Contact:  Shannon Greenfields, Manager, Big Scrub Landcare (PO Box 106,  Bangalow NSW 2479 Australia; . Tel: +61 422 204 294; Email: info@bigscrubrainforest.org.au Web: www.bigscrubrainforest.org.au)

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

Jason Tanner

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 

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

Re-establishing cryptogamic crust at The Waterways, Mordialloc

By Damien Cook

Photo 1.  Crytogamic crust consisting of mosses, lichens and liverworts in inter-tussock space in restored grassland at Waterways. These spaces provide recruitment opportunities for herbaceous species such as Wahlenbergia multicaulis and Brachyscome parvula

Introduction:  The Waterways is a unique urban development on the Mordialloc Creek, in Melbourne’s south eastern suburbs, which combines a housing estate with 48 hectares of restored habitat set aside for indigenous fauna and flora in open space, lakes and other wetlands. (See EMR Project summary ‘The Waterways‘.)

The revegetation of 4 hectares of native grassland and 7 hectares of swamp scrub provided the opportunity to trial the re-establishment of non-vascular plant species, as well as the higher plants which are normally the focus of restoration efforts.

Method. A diversity of cryptogams including Thuidiopsis furfurosa, Hypnum cuppressiforme, Triquetrella papillata and some Rosulabryum and lichen species were collected in the field from nearby remnants of native vegetation threatened with imminent destruction by freeway construction and new housing estates. These were placed in a blender and made into a 2 litre, thick slurry and the slurry was then diluted into a 20 litre a firefighting backpack. The diluted slurry was then applied to bare soils in the revegetated areas at the Waterways in August 2002; some areas were left untreated as a control.

Results. It was not until the wet winter of 2016 that it became apparent how successful this technique had been. There are now quite large areas with a good cover of cryptogams, particularly in the restored grassland and swamp scrub areas. There are some cryptogams in the untreated areas, but the species richness and cover are much lower. Cryptogamic crust cover appears to suppress weed germination, reducing the need for herbicide application, yet provides recruitment opportunities for native forbs (see Photos 1-3).

Acknowledgements. Thanks are due to the Haines family who were the developers of “The Waterways”, and in particular Stephen Haines, for involving us in the revegetation of the site and allowing us scope to trial different ecological restoration techniques. 

Contact: Damien Cook (rakali2@outlook.com.au)

Photo 2. Swamp Scrub at Waterways. Note the dense layer of mosses in the understory, particularly Thuidiopsis furfurosa

Photo 3. Fruiting capsules of a species of Bryum in restored native grassland at Waterways

A water point design to facilitate seed dispersal into revegetation or pasture sites

Amanda N. D. Freeman

Introduction. Although perches have been shown to enhance seed dispersal into revegetation sites, the efficacy of providing a water source to attract seed dispersers is largely untested.  In a Griffith University-led study aimed at “kick-starting” conversion of pasture to forest www.wettropics.gov.au/cfoc , bird-attracting structures that included a perch and water trough at the base were shown to enhance frugivore-assisted seed dispersal.  A complementary study in the same sites has identified the seeds of over 40 bird dispersed species deposited in the water troughs (Amanda Freeman; The School for Field Studies, Centre for Rainforest Studies (SFS-CRS) and Griffith University; 2012-2014, unpublished data).  Although the water troughs demonstrably attracted frugivorous birds, most notably Pied Currawongs (Strepera graculina ) using the water to regurgitate, any seeds regurgitated into troughs would be unavailable to germinate (Fig 1.).

Figure 1. A Pied Currawong at a water trough in a “Kickstart” pasture conversion plot. [See Elgar, A.T., Freebody, K., Pohlman, C.P., Shoo, L.P. & Catterall, C.P. (2014) Overcoming barriers to seedling regeneration during forest restoration on tropical pasture land and the potential value of woody weeds. Frontiers in Plant Science 5: 200. http://dx.doi.org/10.3389/fpls.2014.00200]

Figure 1. A Pied Currawong at a water trough in a “Kickstart” pasture conversion plot. [See Elgar, A.T., Freebody, K., Pohlman, C.P., Shoo, L.P. & Catterall, C.P. (2014) Overcoming barriers to seedling regeneration during forest restoration on tropical pasture land and the potential value of woody weeds. Frontiers in Plant Science 5: 200. http://dx.doi.org/10.3389/fpls.2014.00200%5D

Preliminary trial. Using a commercially available automatic waterer used for poultry, we designed a water point with a water dispenser that is too small for birds to regurgitate or defecate into, allowing expelled seed to fall to the ground.  The device is also simple and relatively cheap to build (<$100 Australian).  Once installed, the device requires little attention because the water remains cool and evaporation is minimal so the water may last several months without replenishing. The waterer, a plastic container which distributes water to a small dish by the action of a float, sits on a sturdy metal base 1.5m high.  The base has a perch allowing birds of different sizes to access the water from several angles and an attachment for a camera to enable bird visits to be monitored.  We envisage that the water point may facilitate seed dispersal by attracting frugivorous birds that will regurgitate and/or defecate at or near the water point.

We conducted an initial trial at a revegetation site at SFS-CRS in February 2016.  For this trial we baited the water point with Kiwi Fruit (Actinidia sp.) but this was soon consumed by insects. During the trial we recorded two species of fruit-dispersing bird, Pied Currawong and Lewin’s Honeyeater (Meliphaga lewinii) using our prototype water point within one month of its installation in (Fig 2.).

figure-2

Figure 2. A Pied Currawong drinking from a water point (kiwi fruit bait in foreground).

Design of second trial. In July 2016 we established a small trial at SFS-CRS to test the relative efficacy of perches alone versus perches coupled with our water point device in facilitating seed dispersal into cleared sites that lack remnant or planted trees.  We have nine fenced 3m2 plots in ungrazed former pasture, 15m from the edge of primary rainforest (Fig 3.).  Six plots have a perch, 3-4m high, cut to standard form from Sarsaparilla (Alphitonia petriei) trees.  Three of these plots also have a water point placed close to the base of the perch and a camera monitoring visits to the water.  Three plots have no structures.

Grass in all plots will be suppressed by herbicide spray (on an ‘as needed’ basis) and seedling recruitment in the plots will be monitored. In the first three months, no birds have been recorded using the water points in the trial plots.

Figure 3. Perch and water device trial plots, September 2016.

Figure 3. Perch and water device trial plots, September 2016.

Contact: Amanda Freeman, Centre Director, The School for Field Studies, Centre for Rainforest Studies, PO Box 141, Yungaburra, QLD 4884, Tel: +61 (7) 40953656; Email:  afreeman@fieldstudies.org

 

 

 

Seagrass rehabilitation and restoration, Cockburn Sound, WA

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

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

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

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

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

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

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

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

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

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

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

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

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

Also see:

EMR project summary – report on the seagrass transplanting trials:

Full EMR feature article

 

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

Hanabeth Luke

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Restoring wetland communities in the Coorong and Lower Lakes, South Australia

[Summary will be reinstated soon.]