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

The Motutapu Restoration Trust 

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

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

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

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

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

Restoration project

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

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

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

The major activities of the ecological restoration are:

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

Planters in action: Photo: MRT

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Evidence that recovery processes are securely occurring on the island

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

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

 Bird species (terrestrial diurnal including waders):

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

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

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

Fish:

  • Giant kokopu (Galaxius argenteus) now

Secure engagement with local  stakeholders.

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

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

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

 

Motuora Restoration Project, New Zealand

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

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 

 

 

A framework and toolbox for assessing and monitoring swamp condition and ecosystem health

Key words: Upland swamp, stygofauna, sedimentology, ecosystem processes, biological indicators, geomorphology

Introduction. Upland swamps are under increasing pressure from anthropogenic activities, including catchment urbanization, longwall mining, and recreational activities, all under the omnipresent influence of global climate change. The effective management of upland swamps, and the prioritisation of swamps for conservation and restoration requires a robust means of assessing ecosystem health. In this project we are developing a range of ecological and geomorphic indicators and benchmarks of condition specifically for THPSS. Based on a multi-metric approach to ecosystem health assessment, these multiple indicators and benchmarks will be integrated into an ultimate index that reflects the health of the swamp.

In this project we have adopted (and modified) the definition of ecosystem health applied to groundwater ecosystems by Korbel & Hose (2011). We define ecosystem health of a swamp as, i.e., “an expression of a swamp’s ability to sustain its ecological functioning (vigour and resilience) in accordance with its organisation while maintaining the provision of ecosystem goods and services”.

Design. Our approach to develop indicators of swamp health followed those used to develop multimetric indices of river and groundwater ecosystem health (e.g. Korbel & Hose 2011). We used the ‘reference condition’ approach in which a number of un- or minimally disturbed swamps were sampled and the variation in the metric or index then represents the range of acceptable conditions (Bailey et al. 1998; Brierley & Fryirs 2005).

We focused initially on swamps in the Blue Mountains area. Reference (nominally unimpacted) and test sites with various degrees and types of impacts were identified using the database developed by the concurrent THPSS mapping project (Fryirs and Hose, this volume).

Following our definition of ecosystem health, we selected a broad suite of indicators that reflect the ecosystem structure (biotic composition and geomorphic structure) and function, including those relating to ecosystem services such as microbially-mediated biogeochemical functions, geomorphic processes and hydrological function, as well as the presence of stressors, such as catchment changes. Piezometers and dataloggers have been installed in a number of swamps to provide continuous data on groundwater level fluctuations and sediment cores taken at the time of piezometer installation have provided detailed information on the sedimentary structure, function and condition of the swamps.

Results. Intact and channelised swamps represent two geomorphic condition states for THPSS. Not surprisingly, variables reflecting the degree of catchment disturbance (such as urbanization) were strongly correlated with degraded swamp condition. Variables related to the intrinsic properties of swamps had little relationship to their geomorphic condition (Fryirs et al. 2016). Intact and channelized swamps present with typically different sediment structures. There were significant differences in the texture and thickness of sedimentary layers, C: N ratios and gravimetric moisture content between intact swamps and channelised swamps (Friedman & Fryirs 2015). The presence and thickness of a layer of contemporary sand in almost all channelised swamps and its absence in almost all intact swamps is a distinctive structural difference.

Disturbed swamps have poorer water quality at their downstream end, and associated with this, lower rates of organic matter processing occurring within the streams (Hardwick unpublished PhD Data). Similarly, the richness and abundance of aquatic invertebrates living within swamp sediments (stygofauna) is poorer in heavily disturbed swamps than in undisturbed or minimally disturbed areas (Hose unpublished data).

Within the swamp sediments, important biogeochemical processes, such as denitrification and methanogenesis, are undertaken by bacteria. In this study we are measuring the abundance of the functional genes such as a surrogate for functional activity within the swamp sediments. There is large spatial variation in the abundance of functional genes even within a swamp, which complicates comparisons between swamps. Within our focus swamp, the location closest to large stormwater outlets had different functional gene abundances, in particular more methanogens, than in less disturbed areas of the swamp. There were greater abundances of denitrification genes, nirS and nosZ, in shallower depths despite denitrification being an anoxic process, which may reflect changes in the surficial sediments due to disturbance. Overall however, the abundance of functional genes seem to vary more with depth than with location, which means that comparisons between swamps must ensure consistency of depth when sampling sediments (Christiansen, unpublished PhD data).

The list of indicators currently being tested in this project and by others in this program (Table 1) will be refined and incorporated into the final assessment framework. Thresholds for these indicators will be determined based on the range of conditions observed at the reference sites. The overall site health metric will reflect the proportion of indicators which pass with respect to the defined threshold criteria. At this stage, the final metrics will be treated equally, but appropriate weightings of specific metrics within the final assessment will be explored through further stakeholder consultation.

Stakeholders and Funding bodies. This research has been undertaken as PhD research projects of Kirsten Cowley, Lorraine Hardwick and Nicole Christiansen at Macquarie University. The research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program. This project was also partly funded by an ARC Linkage Grant (LP130100120) and a Macquarie University Research and Development Grant (MQRDG) awarded to A/Prof. Kirstie Fryirs and A/Prof. Grant Hose at Macquarie University. We also thank David Keith, Alan Lane, Michael Hensen, Marcus Schnell, Trevor Delves and Tim Green.

Contact information. A/Prof. Grant Hose, Department of Biological Sciences, Macquarie University (North Ryde, NSW 2109; +61298508367; grant.hose@mq.edu.au); and A/Prof. Kirstie Fryirs, Department of Environmental Sciences, Macquarie University (North Ryde, NSW 2109; +61298508367; kirstie.fryirs@mq.edu.au).

Table 1. List of indicators of swamp condition that are being trialled for inclusion in the swamp health assesment toolbox.

Functional indicators table

Testate amoebae: a new indicator of the history of moisture in the swamps of eastern Australia

Key words: Temperate Highland Peat Swamps Sandstone

Introduction. Swamps are an ideal natural archive of climatic, environmental and anthropogenic change. Microbes and plants that once inhabited the swamps are transformed and accumulate in undisturbed anoxic sediments as (sub)fossils and become useful proxies of the past environment. Since these systems are intrinsically related to hydrology, the reconstruction of past moisture availability in swamps allows examination of many influences, including climate variability such as El Nino-induced drought. It can also provide baseline information: long (palaeoenvironmental) records can reveal natural variability, allow consideration of how these ecosystems have responded to past events and provide targets for their restoration after anthropogenic disturbance.

Testate amoebae are a group of unicellular protists that are ubiquitous in aquatic and moist environments. The ‘tests’ (shells) of testate amoebae preserve well and are relatively abundant in organic-rich detritus. Testate amoebae are also sensitive to, and respond quickly to, environmental changes as the reproduction rate is as short as 3-4 days. Modern calibration sets have demonstrated that the community composition of testate ameobae is strongly correlated to moisture (e.g. depth to water table and soil moisture) and this allows statistical relationships to be derived. These relationships have been used extensively in European research for the derivation of quantitative estimates of past depth to water table and hence moisture availability.

Although a suite of different proxies have used to reconstruct aspects of past moisture availability in Australia (e.g. pollen, diatoms, phytoliths) very little work on testate amoebae has occurred to date. This project aims to address this deficiency by examining testate amoebae in several ecologically important mires in eastern Australia including Temperate Highland Peat Swamps on Sandstone (THPSS), an Endangered Ecological Community listed under the Environment Protection and Biodiversity Conservation Act 1999 and as a Vulnerable Ecological Community under the NSW Threatened Species Conservation Act 1995.

The project specifically aims to develop a transfer function linking modern samples to depth to water table in THPSS and to then apply this to reconstruct palaeohydrology over the last several thousand years. Our ultimate aims are to use this research to consider the nature and drivers of past climate change and variability and to also address issues associated with recent human impacts. The analysis of testate amoebae will allow us to consider changes in THPSS state, accumulation and stability over centuries-to-millennia, and this will provide context for recent changes, recommendations for the management of peaty swamps on sandstone and analytic tools for assessing whether remediation is resulting in significant improvement on eroding or drying swamps.

Work Undertaken and Results to Date. Research linking testate amoebae and depth to water table in Europe and North America has mostly been undertaken in ombrotrophic (rain-fed) mires. These are distinctly different to THPSS and related communities of the Sydney Basin, which are often controlled by topography (topogeneous mires). In these environments various sediments are known to build up sequentially through time and the minerogenic-rich sediments of the THPSS have resulted in several challenges in our preliminary work. As an example, standard laboratory protocols do not remove mineral particles and these can obscure and make testate amoebae identification difficult. We have since developed a new laboratory protocol and results are promising. We have also been struck by the distinct Northern Hemisphere bias to testate amoebae research: as an example, the Southern Hemisphere endemic species Apodera (Nebela) vas that has been common in our THPSS samples is not included in the most popular guideline book (https://www.qra.org.uk/media/uploads/qra2000_testate.pdf).

Despite the new laboratory protocols we have found that testate amoebae are relatively scarce in THPSS environments. Table 1 outlines the species we are encountering in modern (surface) samples of THPSS and in the high altitude Sphagnum bogs of the Australian Capital Territory: we are finding greater abundance and species richness in the bogs of the ACT.

This project commenced in 2015 and will run until 2017.

Stakeholders and Funding. This research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program.

Contact information. The project testate amoebae as indicators of peatland hydrological state’ is jointly being undertaken by: A/Prof Scott Mooney (School of Biological, Earth and Environmental Science, UNSW +61 2 9385 8063, s.mooney@unsw.edu.au), Mr Xianglin Zheng (School of Biological, Earth and Environmental Science, UNSW, +61 2 9385 8063, xianglin.zheng@unsw.edu.au) and Professor Emeritus Geoffrey Hope (Department of Archaeology and Natural History, School of Culture, History, and Language, College of Asia and Pacific, The Australian National University, +61 2 6125 0389 Geoffrey.Hope@anu.edu.au).

Table 1. A list of the testate amoebae species found in THPSS environments of the Sydney region and in the high altitude bogs of the ACT. (Those with a ++ are more common.)

Mooney table1

The palaeoenvironmental history of Temperate Highland Peat Swamps on Sandstone

Scott Mooney, James Goff and Lennard Martin

Key words (<5 words): sediments, palaeoenvironmental reconstruction, radiocarbon dating

Introduction. Palaeoecology (i.e. study of past environments using fossils and sediment cores) is often used to provide information regarding past environmental conditions. In comparison to modern ecological research, the expanded temporal perspective of palaeoecology unlocks an understanding of pre-anthropogenic variability and how ecosystems have responded to past disturbance and perturbations, thereby allowing consideration of their resilience to various environmental change.

Our Temperate Highland Peat Swamps on Sandstone Research Program (THPSSRP) research has investigated a number of sites in the Blue Mountains and on the Newnes Plateau. Our project aimed to use the sediments accumulating in these sandstone swamps to better understand the dynamics of these ecosystems over time frames that far exceed what is possible through environmental monitoring. We have been documenting the stratigraphy of the sediments using probing and sediment coring/sampling, in association with radiometric (14C, 210Pb) dating, and applying various palaeoenvironmental techniques and proxies to characterize these environments. Our ultimate aims were to characterise recent (historic) trends against the backdrop of a much longer temporal perspective from the palaeoenvironmental analyses and to examine the responses of the swamps over both long (since sediments started accumulating) and short (high-resolution) time frames to disturbance, environmental change and climatic variability.

Sydney Basin Meta-study of Accumulating Sediments. The first component of our research involved a meta-analysis of previous data regarding the ages and organic content of sediments in various depositional environments across the Sydney region. Our aim was to consider rates of sediment accumulation in the post-glacial period (the period since the last glacial maximum, about 21,000 years ago): this information informed our subsequent sampling strategies (e.g. depth of coring, resolution of analyses) and can be used in for future research to better target various chronozones. It is probable that rates of sediment accumulation reflect landscape instability/stability and together with organic content, this provides palaeoenvironmental information relevant to the overall aims of this project. For this component we collated and recalibrated radiocarbon dates (n=132) from 44 sites across the Sydney region, and we identified a subset of 12 sites with quantification of the organic content of the accumulating sediments.

Findings. The synthesis of these data revealed that sedimentation rates underwent a dramatic increase from ~0.2 mm/yr to ~0.6 mm/yr at the beginning of the Holocene (about ~11,700 years ago), which probably reflects post-glacial climatic amelioration. Sedimentation rates remained relatively high during the Holocene, between 0. 4 and 0. 5 mm/yr, although brief decreases are evident, for example centred at 8200, 6500, 2000 and 1200 calibrated radiocarbon years before present (cal. y BP). Only in the last 400 cal y BP do sedimentation rates increase above those present for the majority of the Holocene, peaking at 0.7 mm/yr.

In contrast, organic material began accumulating at around 14,400 cal y BP in these depositional environments, earlier than the 11,700 cal BP increase in sedimentation rates. Before this time all sites exhibited relatively low rates of highly minerogenic sedimentation. After ~14,400 cal y BP the organic content of the sites gradually increased in a trajectory that continued throughout the Holocene, albeit with some major excursions from this trend. As an example, organic content peaked between about 7,500 and 6,000 cal y BP, only to fall to a low at about 5,400 cal y BP, which is then followed by a rapid increase to another peak between about 4,500 and 4,000 cal y BP. This last peak in organic content achieves similar values to the surface/modern samples. This peak (6.7ka)-trough (5.4ka)-peak (4.2ka)-trough (3.2ka) sequence suggests considerable variation in the controls of organic matter production and accumulation, which are mostly climatic parameters. The palaeoenvironmental implications of these results are currently being written for submission to a scientific journal.

Field–based Sampling. Field-based sampling for this research has focused on stable depositional environments in the Sydney region:

  1. Goochs Crater in the Upper Blue Mountains. This site appears to have formed after a rock fall dammed the upper reaches of a relatively narrow valley/canyon. The site is presently a freshwater reed swamp with semi-permanent surface water, although the site has both flooded and burnt since first we first visited. After investigating the stratigraphy and depth of the accumulating sediments, three cores have been collected (G1,G2 & G3) along a transect from the edge to the centre. G1 is a 455 cm long core sampled close to the current waters edge: radiocarbon dating indicates that this represents from the present day back to about 9,500 cal y BP. This core is mostly organic-rich (>60% loss-on-ignition) but these authochthonous sediments are interspersed with abrupt (allochthonous) layers of sand and charcoal, probably transported to this location after major fire events. Our G2 core is 985 cm long and spans the period from about 4,000 to 17,500 cal y BP: it is also highly organic (20-95% loss-on-ignition) but does not include sand/charcoal layers. Core G3 extended down to highly minerogenic sediments at a depth of 795 cm and has a very similar stratigraphy to core G2.
  2. Queens Swamp near Lawson in the Blue Mountains. Queens Swamp was (re-)cored to a depth of 3.8 m and the sediment profile revealed alternating layers of sandy and peaty sediments similar to the edge core (G1) from Goochs Crater. Radiocarbon dating of the Queens Swamp cores suggests a rapidly accumulating upper section of sediments overlying a much older basal layer.
  3. Hanging Rocks Swamp located in Penrose State Forest in the Southern Highlands. A 5.6 m sediment core was also obtained Hanging Rock Swamp and these sediments returned a basal date of 14,500 cal y BP.

Field observations and preliminary results from fieldwork have been published in Quaternary Australasia and Australian Plant Conservation.

Radiocarbon Dating of Sediments. Our THPSS research has involved 35 new radiocarbon (14C) analyses so far across the three sites (Goochs, Queens, Hanging Rock) mentioned above, with a few more planned soon. Twenty of these dates resulted from two AINSE grants, which allowed accelerator mass spectrometry (AMS) 14C dates. This dating was undertaken to develop robust chronologies of the sediments so that palaeoenvironmental changes could be well constrained, but we also undertook some experimentation to consider the optimum sediment fraction for future 14C dating. The sediment fractions considered were charcoal, pollen and short-lived plant macrofossils that were all isolated from the same depth in the sediment profiles. Preliminary results, in preparation for submission at the moment, suggest that charcoal has an inbuilt age of 60-500 years and plant macrofossils return an age closest to the true (modeled) age of that depth.

Preliminary Palaeoenvironmental Interpretation and Conclusions. A variety of palaeoenvironmental techniques have been applied to the sediments sampled from Goochs Crater and together they provide information about past environmental conditions. As an example, sediment humification, which provides clues to surface moisture conditions at the time of deposition, suggests that the period from 9,500 to 7,500 cal y BP was relatively dry, which contrasts with previous palaeoclimatic inferences for this region. As different photosynthetic and metabolic pathways mean that the ratio of carbon/nitrogen can distinguish between aquatic and terrestrial sources of organic matter we analysed this ratio in 32 samples across the G2 core from Goochs Crater. These results suggests that aquatic sources of organic material dominated from 17,500 to 15,000 cal y BP and between 15,000 to 10,000 cal y BP conditions favored both aquatic and terrestrial sources. A rapid departure to highly terrestrial sources was evident at 10,000 cal y BP, after which a gradual change towards contemporary conditions, with a small aquatic influence, was evident.

While this demonstrates that much of the (contemporary) accumulating sediments at Goochs Crater are derived from within the site, it also receives inorganic aeolian materials from a larger source area.  To investigate this component we quantified the grainsize along the sediment profile to reveal that although clay content remains near constant (~ 5%) for the entire period, sand-sized particles shows a distinct increase in the period between 10,000 and 7,000 cal y BP before disappearing from the record. X-ray fluorescence scanning was also conducted on the G2 core resulting in elemental profiles for 32 elements at a very high (1mm) resolution. While the geochemical investigation of peat and organic sediments is in its infancy, several elements show considerable promise as palaeoenvironmental proxies. In our record, titanium, probably resulting from freshly weathered materials and washed in during periods of high surface runoff, is variable between 17,500 and 12,000 cal y BP, followed by sustained low values throughout the Holocene except for an abrupt, brief increase at 10,000 cal y BP followed again by high levels from 9,500 to 8,500 cal y BP. Bromine, which indicates the deposition of marine aerosols, shows an opposite trend to titanium, with low values until the early Holocene when a gradual increase begins, most likely indicating increased maritime influence on the hydrology of the site as sea level rose and stabilized in the post-glacial period.

In summary, it appears that Goochs Crater began accumulating organic sediments around 17,500 cal y BP, shortly after which a small, shallow lake developed and persisted in an otherwise sparsely vegetated landscape. The establishment of shoreline vegetation by about 15,000 years ago contributed to the accumulating sediments and this seems to have occurred under a climate of strong but variable westerly winds. A gradual but increasing oceanic influence affected the site until 10,000 cal. BP. before abrupt drying occurred. Increased sand present in the record during the early Holocene and other information suggests a relatively dry period. During the rest of the Holocene, the site returned to a wet, swampy environment: we are currently re-analysing the edge core with a broader suite of proxies to better characterize the late Holocene and it is envisaged that this will result in a complete moisture-focused palaeoenvironmental record from the site from 17,500 cal. BP to present. In the rest of this project (it will run until the end of 2016) we will finalize the interpretation of the other sites and the synthesis will provide a regional picture of palaeoclimatic influences on these important ecological communities. This work will also be compared to high-resolution fire histories that are being developed across the region.

Stakeholders, Funding and Acknowledgements. This research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program. This work has benefited from discussion with Martin Krogh, Doug Benson, Sarsha Gorissen, Geoff Hope, Roger Good and Jennie Whinam.  This work has also been supported by a 2014 and 2015 AINSE Research Award (ALNGRA14019 and 15019) to SM.

Contact information. The project ‘Palaeoenvironments of sandstone peat’ is being undertaken by A/Prof Scott Mooney (School of Biological, Earth and Environmental Science (BEES) UNSW +61 2 9385 8063, s.mooney@unsw.edu.au), Professor James Goff  (School of BEES UNSW j.gof@unsw.edu.au) and Mr Len Martin (PhD candidate, School of BEES, UNSW, +61 2 9385 8063, lennard@student.unsw.edu.au).

A novel multispecies approach for assessing threatened swamp communities

Hannah McPherson and Maurizio Rossetto,

Key words:   Swamp conservation, chloroplast DNA, genetic diversity, landscape connectivity

Introduction. Little is known about the historical or present-day connectivity of Temperate Highland Peat Swamps on Sandstone (THPSS) in the Sydney Basin (NSW). Recent technological advances have enabled exploration of genetic complexity at both species and community levels.  By focusing on multiple plant species and populations, and investigating intraspecific gene-flow across multiple swamps, we can begin to make generalisations about how species and communities respond to change, thereby providing a solid scientific basis from which appropriate conservation and restoration strategies can be developed.

The study area comprised eight swamps distributed across four sites along an altitudinal gradient: Newnes (1200m); Leura (900m); Budderoo (600m); and Woronora (400m), see figure 1.

Map of the Sydney Basin region showing four study sites and eight swamps. Greyscale shows altitude gradient.

Map of the Sydney Basin region showing four study sites and eight swamps. Greyscale shows altitude gradient.

The aims were:

  • To assess the relative genomic diversity among target species representing a range of life-history traits. This was achieved by sequencing chloroplast DNA and detecting variants in pooled samples from 25 species commonly occurring in swamps.
  • To explore geographic patterns of diversity among swamps and across multiple species by designing targeted genomic markers and screening variants among populations within and between sites (for ten species occurring in up to 8 swamps).
  • To develop a set of simple, effective and standardised tools for assessing diversity, connectivity and resilience of swamps to threats (from mining to climate change).
Fig 2. Broad Swamp, Newnes Plateau (Maurizio Rossetto)

Fig 2. Broad Swamp, Newnes Plateau (Maurizio Rossetto)

Our study comprises three main components:

1. Species-level assessment of genetic variation of swamp species

We have taken advantage of new available methods and technologies (McPherson et al. 2013 and The Organelle Assembler at http://pythonhosted.org/ORG.asm/) to sequence and assemble full chloroplast genomes of 20 plant species from swamps in the Sydney Basin and detect within and between-population variation. This enabled a rapid assessment of diversity among representatives of 12 families and a broad range of life-history traits – e.g. table 1. We are currently finalising our bioinformatic sampling of the data to ensure even coverage of chloroplast data across the species, however these preliminary data show that relative estimates are not a product of different amounts of chloroplast data retrieved (e.g. for the seven species with sequence length greater than 100,000 base pairs variation ranges from absent to high).

2. Swamp-level assessment of variation and connectivity using three target species – Baeckea linifolia (high diversity), Lepidosperma limicola (low diversity) and Boronia deanei subsp. deanei (restricted and threatened species).

From the initial species-level study we selected three very different species for detailed population-level studies. We designed markers to screen for variation within and among sites and explore landscape-level connectivity. We identified the Woronora Plateau as a possible refugium and we have uncovered interesting patterns of gene-flow on the Newnes Plateau. Two species, Lepidosperma limicola and Baeckea linifolia seem able to disperse over long distances while Boronia deanei subsp. deanei showed unexpected high levels of diversity despite very limited seed-mediated gene-flow between populations. Its current conservation status was supported by our findings. A unique pattern was found for each species, highlighting the need for a multispecies approach for understanding dynamics of this system in order to make informed decisions about, and plans for, conservation management.

3. Multi-species approach to assessing swamp community population dynamics

Since the population study approach proved successful we expanded our study to include population studies for a further ten species. This required development of new Next Generation Sequencing (NGS) approaches applicable to a wide range of study systems. This kind of approach will allow us to make informed generalisations about swamp communities for conservation management planning.

Fig 3. Paddy’s Swamp, Newnes Plateau (Anthea Brescianini)

Fig 3. Paddy’s Swamp, Newnes Plateau (Anthea Brescianini)

Table 1. Preliminary results showing relative chloroplast variation among 25 swamp species. Sequence length is in base pairs (bp) and relative level of variation was calculated as sequence length divided by number of variants to obtain an estimate of number of SNPs per base pair.  Relative variation was then categorised as: High (one SNP every <1,000 bp); Moderate (one SNP every 1,000 – <5,000 bp); Low (one SNP every 5,000 – <10,000 bp); Very low (one SNP every >10,000 bp); or absent (no SNPs).

table

Fig 4. Banksia ericifolia (Maurizio Rossetto)

Fig 4. Banksia ericifolia (Maurizio Rossetto)

Results to date. We have assembled partial chloroplast genomes of 20 plant species from THPSS in the Sydney Basin and categorised relative measurements of diversity. Preliminary data from the three target species highlighted the need for multispecies studies and we are now finalizing our results from an expanded study (including 13 species) in order to better understand connectivity and resilience of THPSS and provide data critical for more informed conservation planning. We have produced unique, simple methods for assessing genetic diversity and understanding dynamics at both the species and site levels.

Lessons learned and future directions. We found that individual species have unique patterns of genetic variation that do not necessarily correspond with phylogeny or functional traits and thereby highlight the benefit of multispecies studies. We have developed a unique, simple method for screening for genetic variation across whole assemblages which can be applied to many study systems. Since our data capture and analysis methods are standardised it will be possible in the future to scale this work up to include more species and/or more geographic areas and analyse the datasets together to address increasingly complex research questions about the resilience of swamps in a changing landscape.

Stakeholders and Funding bodies. The following people have contributed to many aspects of this research, including design, fieldwork and data generation and analysis: Doug Benson and Joel Cohen (Royal Botanic Gardens and Domain Trust), Anthea Brescianini and Glenda Wardle (University of Sydney), David Keith (Office of Environment and Heritage).

This research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd. Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program.

Contact. Hannah McPherson, Biodiversity Research Officer, Royal Botanic Gardens and Domain Trust, Mrs Macquaries Road, Sydney 2000; Tel: +61292318181 Email: hannah.mcpherson@rbgsyd.nsw.gov.au

Hydrology of Woronora Plateau Temperate Highland Peat Swamps on Sandstone

William C Glamore and Duncan S Rayner

Key words: water balance, groundwater, soil, subsidence, under mining

Introduction. The Temperate Highland Peat Swamps on Sandstone (THPSS) ecological community consists of both temporary and permanent swamps developed in peat overlying Triassic Sandstone formations at high elevations, generally between 400 and 1200 m above sea level on the south-east coast of Australia. THPSS are listed as an endangered ecological community (EEC), threatened by habitat destruction and modification of groundwater and hydrology. The primary impact of longwall mining is to swamp hydrology, influencing long-term surface and groundwater regimes. This, in turn, can have a devastating impact on swamp ecology including many important habitats for protected flora and fauna. While the ecological value of THPSS is well understood, our current understanding of the hydrology of THPSS is limited. THPSS have been found to be dependent on groundwater, and subsequently the impact of modifying groundwater interactions can be significant. Recent research has concluded that a thorough understanding of the impact of longwall mining on the surface waterways and groundwater system is necessary before any remediation options to reduce loss of water into subsurface routes and minimise impact on water quality are considered.

Aims. To address this major knowledge gap, research into the fundamental hydrology of THPSS was undertaken. The purpose of this investigation was to understand the role of surface water and groundwater inputs and losses in maintaining swamp hydrology, providing a base level foundation from which the impacts of long-wall mining on ecology can be determined and guide future remediation efforts. To undertake on-ground research, multiple locations where data collection in peat swamps was being undertaken were utilised to form a foundation from which to expand swamp investigations and target site data gaps. Two swamps were selected for further detailed investigations, both located on the Woronora Plateau, approximately 80km south of Sydney, Australia. One site was within the Woronora Nature Reserve, where vegetation has been monitored regularly for 30+ years and basic climate monitoring for the past 5 years, and another swamp within the Sydney Metropolitan Catchment Management Area where climate monitoring, groundwater levels and swamp discharge has been monitored for the previous 5 years.  Extensive on-ground investigations were undertaken (and continue to be monitored) at these sites, providing fundamental scientific information for further assessment.

Methods. A series of groundbreaking on-ground investigations were undertaken to characterize the swamp hydrogeology and surface hydrology.  Detailed surveys of peat depth were initially undertaken using a push rod and RTK-GPS to determine digital elevation models (DEM) of surface topography and subsurface sandstone. Depth to underlying sandstone was found to be variable throughout the swamps (Figure 1). This survey guided the location and density of soil profiles and piezometer installations to characterize sediment characteristics, monitor water level fluctuations and assess water and soil chemistry.  A total of 17 piezometers were installed to bed rock, including logging soil stratigraphy and soil grab samples. Slotted 50mm diameter PVC was installed with a water level logger deployed near the bedrock. Soil samples were analysed for pH, EC, moisture, organic matter and a suite of analytes via ion chromatography. Hydraulic conductivity of the upper peat layer was also tested in-situ. Collected field data and site characterization surveys were combined to construct a three-dimensional numerical hydrological groundwater model to assist in determining the swamp water balance, hydrodynamics and to refine future sampling/analysis.

Figure 1: Example swamp depth survey and piezometer locations with conceptual groundwater flow paths

Figure 1: Example swamp depth survey and piezometer locations with conceptual groundwater flow paths

Findings. Findings include fundamental swamp hydrogeolgical characteristics, water balance summaries and analysis of degrees of freedom.  Swamp sediments were observed to vary both within swamps and between swamps. Sediment depths were found to range between 0.5 m to 2.6 m deep, with typical peat depths ranging between 30 cm – 100 cm of a dense organic layer in various stages of decomposition. The organic layer is underlain by grey sandy clay with clay content decreasing with depth (Figure 2). Sand and gravel was observed in the 10 cm to 30 cm range above bedrock.  Soil acidity was observed to be relatively uniform over depth with an average pH 5.7, however electrical conductivity and chloride decreased with depth; suggesting evapo-concentration of salts within the upper layers of the swamp. Soil moisture by weight and organic content were measured to decrease with depth, indicating decreasing porosity. Specific yield of swamp surface soils (0 m to 0.2 m) ranged between 15-20%, with deeper sediments (0.2 m to 0.4 m) approximately 10% greater.

Analysis of the water levels across the swamps, in conjunction with preliminary water balance modelling, indicates that despite the current data collection program, significant degrees of freedom remain unaccounted. Key factors such as transpiration, runoff, infiltration, interflow and groundwater losses are currently unknown and present seven sources of uncertainty within the water balance model. To reduce the uncertainty and close the water balance of peat swamps, further long term monitoring and site specific measurements are required. With the addition of soil core samples, soil hydraulic conductivity, long term water level data and further swamp geometry data, eight out of a total of nine water balance quantities will be known for the swamp, enabling increased reliability to assess the impacts of climate change, changes in land use, and undermining on long-term swamp ecology.  The findings from this study provide fundamental information that forms the basis for ongoing investigations critical for understanding peat swamp hydrology.

Figure 2: Typical swamp lithology

Figure 2: Typical swamp lithology

Acknowledgements. This research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program.

Contact. William C Glamore and Duncan S Rayner, Water Research Laboratory, School of Civil and Environmental Engineering, UNSW Australia (110 King St, Manly Vale, NSW 2093, Australia, Tel: +61/ 2 8071 9868. Email: w.glamore@wrl.unsw.edu.au ).

Conservation of an endangered swamp lizard

Key words:         Eulamprus leuraensis, fire impacts, disturbance ecology, habitat requirements, Scincidae

The Blue Mountains Water Skink is known from less than 60 isolated swamps in the Blue Mountains and Newnes Plateau of southeastern Australia (Fig 1). Understanding the species’ ecology, notably its vulnerability to threatening processes such as fire and hydrological disturbance, is essential if we are to retain viable populations of this endangered reptile.

Fig 1. Swamps containing Eulamprus leuraensis used in our baseline surveys (from Gorissen et al., 2015)

Fig 1. Swamps containing Eulamprus leuraensis used in our baseline surveys (from Gorissen et al., 2015)

Design: We surveyed swamps across the species’ known range to identify critical habitat requirements, and to examine responses both of habitat features (vegetation) and lizard populations to fire regimes and other anthropogenic disturbances. Our analyses of fire impacts included both detailed studies post-fire, and GIS-based analyses of correlations between lizard abundance and fire history.

Results to date: Blue Mountains Water Skinks appear to persist wherever suitable swamp habitat is maintained, although lizard numbers decline after frequent fires, hydrological disturbance or urbanization. However, the lizards (especially, adults) rarely venture out from the core swamp habitat into the surrounding woodland matrix. The “fast” life-history of this species (rapid growth, early maturation, high reproductive output) enables populations to recover from local disturbances, but very low vagility means that re-colonisation of a swamp after extirpation of a population is likely to be very slow (if it occurs at all).

Fig 2. Blue Mountains Water Skink within its swamp habitat (Photo: S. Dubey)

Fig 2. Blue Mountains Water Skink within its swamp habitat (Photo: S. Dubey)

Fig 3. Sarsha Gorissen checks a trap for lizards in a Newnes Plateau swamp (Photo: N. Belmer)

Fig 3. Sarsha Gorissen checks a trap for lizards in a Newnes Plateau swamp (Photo: N. Belmer)

Lessons learned and future directions: The suitability of a montane swamp for Blue Mountains Water Skinks can be readily assessed from soil-moisture levels and vegetation characteristics. Effective conservation of this endangered reptile species should focus on conserving habitat quality in swamps, rather than targeting the lizards themselves. If healthy swamps can be maintained, the lizards are unlikely to face extinction. Given high levels of genetic divergence among lizard populations (even from adjacent swamps), we need to maintain as many swamps as possible.

Stakeholders and Funding bodies: This research was funded through the Temperate Highland Peat Swamps on Sandstone Research Program (THPSS Research Program). This Program was funded through an enforceable undertaking as per section 486A of the Environment Protection and Biodiversity Conservation Act 1999 between the Minister for the Environment, Springvale Coal Pty Ltd and Centennial Angus Place Pty Ltd.  Further information on the enforceable undertaking and the terms of the THPSS Research Program can be found at www.environment.gov.au/news/2011/10/21/centennial-coal-fund-145-million-research-program.

Contact information: Prof Richard Shine, School of Life and Environmental Sciences, Heydon-Laurence Building A08, University of Sydney, NSW 2006 Australia. Phone: (61) 2-9351-3772; Email: rick.shine@sydney.edu.au

Landscape-scale terrestrial revegetation around the Coorong, Lower Lakes and Murray Mouth, South Australia

Hafiz Stewart, Ross Meffin, Sacha Jellinek

Key words. Restoration, prioritisation, woodland, ecosystems

Introduction. Located in South Australia at the terminus of the Murray-Darling River, the Coorong, Lower Lakes and Murray Mouth (CLLMM) region has immense ecological, economic and cultural importance. The landscape varies from the low hills of Mount Lofty Ranges in the northwest, through the low valleys and plains surrounding Lake Alexandrina and Lake Albert, to the plains and dunes of the Coorong in the southeast (Fig 1). These landforms had a large influence on the composition of pre-European vegetation communities in the region, with the Mount Lofty Ranges dominated by eucalypt forests and woodlands, the lakes surrounded by a mixture of mallee, temperate shrublands and wetland vegetation, and the Coorong supporting coastal and wetland vegetation communities.

The region has been extensively cleared since European settlement and the introduction of intensive agriculture (cropping and grazing), so that now only a fraction of the original native vegetation remains. This has resulted in a substantial decline in biodiversity and recognition of the area as a critically endangered eco-region. These impacts have been compounded by water extraction upstream and anthropogenic changes to hydrological regimes. The recent drought further exacerbated these environmental problems and severely affected the region’s people and economy.

Fig. 1. The Coorong, Lower Lakes and Murray Mouth region showing terrestrial and aquatic plantings.

Figure 1. The Coorong, Lower Lakes and Murray Mouth region showing terrestrial and aquatic plantings.

Broad aim and any specific objectives. In response to drought and other issues affecting the region the Australian and South Australian governments funded the landscape-scale CLLMM Recovery Project (2011 – 2016). This project aims to help restore the ecological character of the site and build resilience in the region’s ecosystems and communities. As a part of this, the CLLMM Vegetation Program aimed to strategically restore native vegetation to buffer and increase the connectivity of existing remnants.

Works undertaken. Three key tools were utilised to achieve these goals. First, an integrated Landscape Assessment was used to identify priority plant communities for restoration in the region. To do this, we classified vegetation types occurring in the CLLMM landscape, then identified suites of bird species associated with each vegetation type. The status and trends of each of these bird species were then used as indicators to determine the conservation priority of each vegetation type. Second, a framework was developed to identify the most appropriate vegetation types to reconstruct at a given site, depending on characteristics such as soil type and landform. This was based on the composition and structure of remnant communities and their associated environmental settings. Finally, a Marxan analysis was conducted across the region to prioritise sites for restoration works based on the aims of the program, with an aspirational target of restoring 30% of each priority vegetation type. Following an expression of interest process that made use of existing networks in the local community and the traditional owners of the CLLMM and surrounding area, the Ngarrindjeri, prioritised sites were then selected from those made available by landholders.

For each site, we developed a plan specifying the site preparation required, and species and densities to be planted. Native plants were sourced from local nurseries, ensuring that provenance and appropriate collection guidelines were followed. Tubestock was used to provide an opportunity for social benefits, including the development of community run nurseries, and due to their higher survival rates. Planting was carried out by regional contractors engaged by the CLLMM Recovery Project Vegetation Program, along with the Goolwa to Wellington Local Action Planning association and the Ngarrindjeri Regional Authority. During this program wetland restoration was also undertaken through the planting of a native sedge species, the River Club Rush (Schoenoplectus tabernaemontani), which assisted in stabilising shorelines and creating habitat for aquatic plant communities.

Results to date. By the end of the program around 5 million native plants will have been planted at 148 sites on private and public land covering more than 1,700 hectares (Fig. 1). In total 202 species of plants have currently been planted, comprising 11% overstorey, 38% midstorey and 51% understorey species. Initial results indicate that around 66% of plants survive the first summer, at which point they are well established. Woodland and mallee bird species are starting to use these revegetated areas. When compared to remnant areas of the same vegetation type, both native plant species richness and bird diversity are lower in restored habitats. However, while the bird communities in restored habitats are dominated by generalist species, specialist species such as endangered Mount Lofty Ranges Southern Emu-Wrens have been recorded in revegetated areas, providing early signs that planted areas are benefiting rarer species. The restored communities are still very young, and over time we expect these areas will start to structurally resemble remnant habitats.

Lessons learned and future directions. Resourcing of research alongside program delivery allowed us to implement a sound prioritisation process and a systematic, strategic, and effective approach to the restoration of the landscape. The capacity to collect good vegetation, soil and bird occurrence data was crucial to this. Successful delivery also required funding for site preparation and follow-up, a well-developed network of native plant nurseries, engaged community and indigenous groups, and good relationships with local landholders.

Stakeholders and Funding bodies. The CLLMM Vegetation Program is a landscape scale habitat restoration project, jointly funded by the Australian and South Australian governments under the Coorong, Lower Lakes and Murray Mouth Recovery Project. We would like to thank the Goolwa to Wellington Local Action Planning Association, the Milang and Districts Community Association and the Ngarrindjeri Regional Authority for their assistance in undertaking this revegetation. DEWNR’s Science, Monitoring and Knowledge branch undertook the initial ecosystem analysis.

Contact information.  Hafiz Stewart, Department of Environment, Water and Natural Resources, South Australia. Hafiz.stewart@sa.gov.au