Wetlands Australia NATIONAL WETLANDS UPDATE SEPTEMBER 2012—Issue No 21

Wetland Rehabilitation, Restoration and Conservation

Other chapters can be downloaded from:

www.environment.gov.au/water/publications/environmental/wetlands/wetlands-

australia/wa21/downloads.html

40 | Wetlands Australia September 2012

WETLAND REHABILITATION, RESTORATION AND CONSERVATION

Looking for mice in the mangrovesCheryl Bolzenius, WetlandCare Australia

A nationally vulnerable water mouse has been discovered at a wetland rehabilitation site on the Maroochy River, on Queensland’s Sunshine Coast. The mouse (Xeromys myoides) was previously unknown at this site, until several nests were discovered in late 2011 by a worker from the Queensland Parks and Wildlife Service (QPWS).

The water mouse inhabits coastal areas of central and south east Queensland, Northern Territory and New Guinea, and is typically found in coastal saltmarsh and mangrove areas. A key sign of their presence is their nesting mounds, which range from free-standing mounds in saltwater couch grasslands to sheltered mounds in opportunistic sites such as the base of old grey mangrove trees (Avicennia marina) located within the intertidal zone. The water mouse forages in the mangroves at night, feasting on invertebrates such as crabs, shellfish and snails. Loss, fragmentation and degradation of their mangrove and saltmarsh habitats are key threats to their survival.

The Maroochy River site includes mangrove, casuarina and saltmarsh communities and is part of WetlandCare Australia’s Coastal 20 Wetlands Program. WetlandCare Australia is working with project coordinator Nina Kaluza, QPWS and

community volunteers to survey and monitor water mice along a 1.7 kilometre stretch of the Maroochy River covering several land tenures. In total 132 nesting mounds have been located, mapped, and information recorded on their distribution, habitat preferences of water mice and potential threats including erosion and invasive weeds.

Staff from WetlandCare Australia undertaking site surveys of water mouse mounds (Adam Gosling).

41

As part of this project, Traditional Owners are undertaking rehabilitation to address threats and protect this specialised mammal’s habitat. Weed control along the banks of the Maroochy River is underway to remove broad-leaf pepper tree (Schinus terebinthifolius), singapore daisy (Sphagneticola trilobata) and ground asparagus (Asparagus aethiopicus cv. Sprengeri). Mangroves are being propagated and reinstated to prevent further erosion of coastal saltmarsh. The habitat rehabilitation will also benefit many threatened and migratory species that rely on these vegetation communities.

WetlandCare Australia and the project team have formed linkages with other organisations undertaking similar water mouse projects in SE Queensland to share knowledge and information. Data collected through these projects will guide future conservation activities and support key actions identified in the national recovery plan for the water mouse.

The Coastal 20 Wetlands Program commenced in 2011 to celebrate WetlandCare’s 20 years of achievement in wetland conservation. The Australian Government has committed a $2.5 million budget for the program through Caring for Our Country. The program involves working in partnership with community, government and industry to rehabilitate 20 important wetlands from Gladstone in southern Queensland to Kempsey on the northern NSW coast.

More detailed information on WetlandCare Australia’s Coastal 20 Wetlands program can be found at www.wetlandcare.com.au, on Facebook at www.facebook.com/wetlandcare or contact WetlandCare Australia’s Coastal 20 Coordinator Adam Gosling, phone (02) 6681 6169 or email adamgosling@wetlandcare.com.au.

Water mice captured on motion sensor monitoring cameras (Nina Kaluza).

42 | Wetlands Australia September 2012

From dry to DAAMMP- restoring an ephemeral systemDeborah Bogenhuber, The Murray-Darling Freshwater Research Centre, Mildura

The Great Darling Anabranch, in south-west New South Wales, is an ancestral path of the Lower Darling River, approximately 480 kilometres long. It is a naturally ephemeral system, but was managed as a permanent water storage supply for landholders until early this century. Water was maintained behind the various block banks/regulators with little to no end of system flow into the Murray River.

Collaboration between landholders, managers, government and scientists over many years resulted in the construction of a pipeline in 2007, to secure water supply and return the Darling Anabranch to an ephemeral system. The Darling Anabranch Adaptive Management

Monitoring Program (DAAMMP) was established to monitor ecological responses to the changed hydrology. Monitoring began in 2010, funded by the New South Wales Office of Environment and Heritage, and the program is expected to continue until 2020.

The DAAMMP includes annual condition monitoring of understorey vegetation communities and riparian tree health, and intervention monitoring of fish, frog and waterbird communities during managed and natural flows. In September 2010, an environmental flow was released down the Anabranch, which was superseded by an overbank flood by mid-October. The Anabranch flowed its full length for the first time in over 10 years.

At the time of the 2011 survey, many of the monitored sites had recently exposed damp sediments, following flood recession. These conditions are required for the germination and

In-channel survey site after flood recession with groundcover of amphibious species including Limosella australis and Callitriche sonderi (D. Boganhuber).

43

Diverse understorey community with amphibious and damp-loving species (D. Boganhuber).

recruitment of many common ‘damp-loving’ plant species along the Darling Anabranch. Therefore the understorey landscape underwent a significant shift from being dominated by terrestrial, dry-loving species in 2010, to one dominated by amphibious and damp-loving species in 2011.

However, hydrological differences occurred along the Darling Anabranch, and persisted at the time of monitoring. This resulted in different plant communities being recorded in different parts of the system. Sites that experienced a ‘natural’ flood recession differed from sites that did not (due to regulation by man-made structures) in the following ways:

• higher species and functional group diversity at all elevations

• lower proportion of exotic species

• high abundances of amphibious and ‘damp-loving’ species.

Of interest was the lack of submerged and to some extent amphibious emergent species recorded throughout the system. As further data is collected, it is anticipated that this will be combined with historical research, seed bank trials and understorey surveys in more stable backwater habitats to investigate the question: Were aquatic vegetation communities in inundated zones ever a major component of the vegetation community along the Darling Anabranch?

For further information contact info@mdfrc.org.au

44 | Wetlands Australia September 2012

Bibra lake rehabilitation and climate change Chris Beaton, The City of Cockburn

The City of Cockburn is a large outer metropolitan council on the outskirts of Perth Western Australia. Two chains of wetlands, known as the Beeliar wetlands, run through the heart of the City. Bibra Lake is one of the larger lakes within these wetland chains.

Past development and grazing has severely impacted the lake vegetation leaving much of the surrounding area in a degraded condition. The City of Cockburn, in conjunction with the Cockburn Wetlands Education Centre (CWEC), a community volunteer organisation, has been rehabilitating Bibra Lake for a number of years with the intent of restoring the lakes riparian vegetation and re-creating habitat.

The need to rehabilitate our wetlands is becoming increasingly important due to the effects of climate change. South west Western Australia has experienced a 15–20 per cent reduction in rainfall since the 1970s (Petrone et al, 2010). In 2010 Perth experienced its second driest year on record with 503.8 millimetres of rainfall, while the driest year was 466.8 millimetres in 2006. The long term average is 850.0 millimetres. As a result of reduced rainfall, groundwater levels are falling.

Bibra Lake is one of the wetlands of the Swan Coastal Plain, these wetlands are surface expressions of the groundwater table. If average groundwater levels continue to drop, this could have severe consequences for the wetlands. Although many of the wetlands in the region regularly dry out, the frequency and the length of time they remain dry has been increasing for approximately a decade.

Bibra Lake revegetation from birdhide in September 2010 (Linda Metz).

45

There is little that can be done to supplement water levels in the wetlands. It has been observed over the past 10 years that, as rainfall continues to reduce, dry land species have begun colonising areas that were previously wetland. Correspondingly, wetland species have shifted downslope onto the newly or increasingly exposed mudflats.

In order to allow wetland systems to adapt naturally to the changing climate, the system needs to be as resilient as possible. Both the City and CWEC volunteers are building this resilience by reducing other threats such as weeds, degradation and unauthorised vehicle access.

So far more than 5.25 hectares have been rehabilitated with planting of appropriate endemic species using a combination of volunteer hours, City resources and grants.

Reference

Petrone, K. C., Hughes, J. D., Van Niel, T. G. and Silberstein, R. P. 2010, Streamflow decline in southwestern Australia, 1950–2008, Geophysical Research Letters 37.

Bibra Lake revegetation from the same birdhide in June 2012 (Linda Metz).

46 | Wetlands Australia September 2012

Southern Macquarie Marshes stream enhancement projectTim Hosking, New South Wales Office of Environment and Heritage

A new project is underway to maximise the environmental benefits gained from floods and environmental flows in the southern Macquarie Marshes and to help protect downstream wetlands.

The geomorphic characteristics (e.g. size, shape and location) of channels and wetlands in the Macquarie Marshes, in north central New South Wales, have changed considerably in the past 50 years. While gradual channel change and the occasional movement of channels on the floodplain are natural processes, human activities have affected key aspects of the system, such as:

• additional erosion and channel scouring due to change in river flows reaching the marshes (related to river regulation and floodplain development)

• increased sediment loads entering the marshes from catchment disturbance

• de-stabilisation of stream banks due to a combination of factors such as hydrology, drought, invasive species and land use

• historical stream intervention works leading to further changes over time, such as a block banks and weirs that are unsuitable for current conditions.

The changes to channel profiles have contributed to ecological degradation in some areas of the Macquarie Marshes, particularly where floodplain wetlands have become disconnected from their feeder streams.

The southern area of the Macquarie Marshes in particular has undergone, and continues to undergo, significant channel changes and associated degradation of floodplain wetlands on both public and private lands. This section of the marshes is the first major filter for sediment entering the system from upstream and acts as a buffer zone between the river and other high conservation value wetlands further downstream.

The Southern Macquarie Marshes Stream Enhancement Project will identify potential erosion control and stream restoration works and will examine the hydrological effects of such measures at the wetland system level. The project will ultimately deliver a recommended plan of works and measures that will aim to restore floodplain connectivity to maximise the ecological benefits from floods and environmental flows.

Existing in-stream erosion and sediment control works in ‘The Breakaway’ channel, Macquarie Marshes Nature Reserve (south) (Tim Hosking and New South Wales Office of Environment and Heritage).

47

These works will also directly protect wetlands downstream by reducing the transport of silt that chokes channels causing redirection of water and increased stream instability.

The project began in April 2012 and will be completed by early 2013. The project is managed by New South Wales Office of Environment and Heritage in association with Barma Water Resources. A steering committee comprising government and land manager representatives has been established to support the project.

The project is funded under the Australian Government’s Environmental Works and Measures Feasibility Program.

For further information on the project contact: Tim Hosking NSW Office of Environment and Heritage, Dubbo tim.hosking@environment.nsw.gov.au or

Daren Barma, Director, Barma Water Resources BWR01@optusnet.com.au

The Breakaway channel, Macquarie Marshes Nature Reserve (south) (Tim Hosking and New South Wales Office of Environment and Heritage).

48 | Wetlands Australia September 2012

Restoring tidal inundation to improve estuarine wetland habitat in Hexham SwampDean Chapman, Amanda Hyde, Hunter-Central Rivers Catchment Management Authority

The Hexham Swamp Rehabilitation Project involves the progressive opening of floodgates on Ironbark Creek to restore 650 hectares of estuarine wetland in the internationally recognised Hexham Swamp, part of the Hunter Estuary Ramsar Site near Newcastle, NSW.

The project aims to reinstate tidal inundation to promote the transition of dominant freshwater vegetation to estuarine wetlands. The expected outcomes include the restoration of nursery habitat for fish and prawns and an increase in visitation of waterbirds including migratory waders, protected under international agreements.

The floodgates were originally installed in the early 1970s, as part of the Lower Hunter Flood Mitigation Scheme to prevent floodwater from the Hunter River entering the swamp. However, the closed floodgates eliminated tidal inundation with negative environmental impacts evident almost immediately.

By 2002, the area of mangroves had reduced from 180 to 22 hectares, saltmarsh had reduced from 900 to six hectares and common reed (Phragmites australis) had expanded its range from 170 to 1005 hectares.

The rehabilitation project was approved by the New South Wales Department of Planning in November 2006 and the first of eight floodgates was opened in December 2008, achieving a major milestone for the project after 12 years of planning, research and stakeholder consultation.

Hexham Swamp, a mosaic of habitats (Hunter Central Rivers Catchment Management Authority).

49

The total cost of the project was $7 million for land acquisition, bund construction and ecological surveys. The complex process required innovative methods including the development of easements for inundation.

The project is currently in stage three with six of the eight floodgates open allowing for tidal inundation of about 380 hectares.

Stage three has seen a notable transition from phragmites-dominant freshwater wetland to a mosaic of habitats including mangroves, saltmarsh and open water.

Rigorous monitoring of vegetation, birds, mosquitoes, fish and invertebrates, benthic macroinvertebrates, water levels and water quality continues. Significant bird sightings from summer 2012 include the migratory Latham’s snipe and black-necked stork.

Parts of the swamp remain freshwater and continue to provide habitat for species such as the Australasian bittern, known to inhabit Hexham Swamp.

The remaining two floodgates are due to be opened later in 2012. The challenge is to continue to balance the transition without causing any deleterious impacts to water quality and wildlife while also meeting community expectations.

Implementation of earth works continues throughout stage three to improve drainage of properties on the project boundary while monitoring of mosquito populations continues.

For further information contact Hunter-Central Rivers Catchment Management Authority on (02) 4930 10130.

Ironbark Creek floodgates - 6 open, 2 to go (Hunter Central Rivers Catchment Management Authority).

50 | Wetlands Australia September 2012

51

Rehabilitation brings swamp wallaby back to Marmong Wetlands Maree Edwards, Lake Macquarie Landcare

Swamp wallabies have returned to Marmong Wetlands at Lake Macquarie in New South Wales after their habitat has been restored by the efforts of dedicated volunteers.

The swamp wallaby (Wallabia bicolor) also commonly known as the black wallaby is a small macropod marsupial. Swamp wallabies are active day and night, although they generally prefer to shelter until grazing at dusk. This little creature (pictured) was not shy in coming forward to say thank you to local Landcare volunteers for rehabilitating the wetland site for their species and other delightful native creatures.

Marmong Point Landcare Group (MPLG) formed in April 2010 when Bob Jones decided to clear the wetland area of lantana with Jeannine O’Riley. Together they continue to spend approximately ten hours work each week rehabilitating the site. Jeannine and Bob’s commitment to rehabilitating Marmong Wetland, together with the assistance provided by the Lake Macquarie Landcare Bush Regeneration and Green Teams, has transformed this previously highly degraded wetland site. Residents, hikers, and school students are now able to enjoy this beautiful environment and experience the native flora and fauna that are thriving in the transformed habitat.

MPLG coordinates their Landcare activities with neighbouring Marmong Creek Landcare group who work further up the catchment rehabilitating the riparian zones of Marmong Creek. With guidance from Lake Macquarie Landcare Resource Centre, both groups aim to work towards a ‘whole catchment’ rehabilitation outcome.

The work is supported through an Australian Government Caring for Our Country Community Action Grant, augmented with wetland restoration funding provided by Lake Macquarie City Council. The funding has enabled the Lake Macquarie Landcare Bush Regeneration team to work through the site targeting transformer weeds such as blackberry, camphor laurel, cassia, castor oil plant, giant reed, lantana, madeira vine, Norfolk Island hibiscus, ochna, Turkey rhubarb, and wild tobacco.

As the wetland edge adjoins the suburban interface, the management of both the buffer zone and the wetland’s environmental assets are priorities. Planting will establish an edge to the mown zone and mosaic planting under mature trees will restore native flora and fauna values to this part of the reserve.

Most importantly, the ongoing work of the Landcare group is to maintain and extend the professionally funded works to benefit the environmental integrity of the site. Who knows how many more native species will be seen here in a further two years time.

For further information visit www.lakemacquarielandcare.org/Files/Uploads/File/Resources/Marmong%20Wetlands%20Case%20Study.pdf

Opposite page: Swamp wallaby at Marmong Wetlands (Jeannine O’Riley).

52 | Wetlands Australia September 2012

Toolibin Lake inundation trialJennifer Higbid and Paul Drake, Western Australian Department of Environment and Conservation.

The BioRisk project in Western Australia is a great example of collaboration and science informing wetland management in an agricultural zone.

Toolibin Lake is a Ramsar-listed ephemeral wetland located 200 kilometres south-east of Perth. It is being studied as part of the BioRisk project, a partnership between the Western Australian Department of Environment and Conservation, the Future Farm Industries Cooperative Research Centre and the University of Western Australia.

Toolibin Lake is one of the last remaining fresh-to-brackish wetlands in the south-west agricultural zone. The lake bed vegetation is a nationally listed endangered ecological community. In the 1990s, a recovery plan was implemented to address threats to the lake from altered hydrology, particularly secondary salinity.

The Toolibin Lake recovery plan has guided various management actions, including revegetation and engineering works. Long-term monitoring indicates that these actions have largely halted the decline of the lake bed vegetation since around 2006; however, there has not been wholesale recovery and this prompted an investigation into plant- and hydrological-processes.

The water requirements and tolerances of the two dominant trees on the lake bed—sheoak (Casuarina obesa) and paperbark (Melaleuca strobophylla)—are being studied to help understand the connection between growth and water use by the trees and hydrology.

Below-average rainfall and a lack of natural inflow events meant that understanding of the interactions between surface water, soil properties and plants had to be derived from models. To test these models and understand the dynamics of salt and water movement during inundation, a small flooding trial on the lake bed was conducted.

The inundation trial site at Toolibin Lake (Jennifer Higbid, Western Australian Department of Environment and Conservation).

53

During March 2011, a rectangular bund (15 metres long, by 10 metres wide, by 0.5 metres high) was constructed on the lake bed. The bund contained more than 100 trees, both sheoaks and paperbarks, with some trees fitted with sensors to measure tree girth and sap flow. Sensors were also deployed to measure water and soil parameters. Over two weeks, 100 000 litres of fresh water was applied to the bund and a water depth of more than 30 centimetres was maintained for seven days.

The trial confirmed the different rooting depths of the trees and demonstrated that they can rapidly increase water use following flooding, particularly the sheoak. The discovery of different root zone niches used by the two species (sheoak roots are shallower than the paperbark’s) helps to explain the sequence of tree deaths that has occurred and the ecological requirements that management must consider.

It also showed that surface and groundwater rapidly connect, which is provoking additional research to better guide groundwater management.

For further information visit www.dec.wa.gov.au/content/view/451/950/

Sap flow sensors in a Casuarina obesa tree (Jennifer Higbid, Western Australian Department of Environment and Conservation).