Category Archives: Riparian & stream ecology

Restoring the banks of the Namoi on Kilmarnock – UPDATE of EMR feature

Robyn R. Watson

[Update of EMR feature – Watson R. (2009) Restoring the banks of the Namoi on ‘Kilmarnock’: Success arising from persistence. Ecological Management & Restoration,  10: 1 pp 10-19 https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2009.00434.x]

Figure 1. Casuarina (Casuarina cunninghamiana), River Red Gum and a range of grasses established on river bank at Kilmarnock after restoration works. (Photo R. Watson)

Riverbank restoration began on Kilmarnock in early 1990 with fencing the river area and planting native trees, shrubs and grasses. A program of killing the weeping willows resulted in their elimination by 2000. Tree lines were planted to connect the river corridor to natural conservation areas around the farm and this has resulted in a gradual increase in native wildlife leading to great environmental benefits both for the farm and surrounding areas.

Prior to the works the riparian zones on Kilmarnock had degraded to the extent that the banks were slumping during floods, with loss of old trees. This had arisen from decades of clearing, grazing and weed invasion.  Since 2009 we can report that the fenced-off river corridor has continued to recover with native grasses  beneath the trees, particularly Phragmites (Phragmites australis)  and Vetiver Grass (Chrysopogon zizaniodes) which are growing well on the steep river banks (Fig 1).  As the trees in the riparian corridor grew, additional tree lines were planted throughout the farm to connect the riparian zone to retained native vegetation areas and other set-aside conservation areas. This has led to an increase in native birds, micro bats and beneficial insect numbers.

Wildlife have returned to the area, including Little Pied Cormorant (Microcarbo melanoleucos) and  Pied Cormorant (Phalacrocorax varius) nesting in the River Red Gum (Eucalyptus camaldulensis) trees one year. Flocks of Budgerigar (Melopsittacus undulatus) and Spotted Pardalote (Pardalotus punctatus)  have been observed in the trees along the riparian zones.  Pink Eared Duck (Malacorhynchus membranaceus), Musk Duck (Biziura lobata)(, Eurasian Coot (Fulica atra) and Brolga (Antigone rubicunda) visited wetland areas on the farm. There has been a noticeable increase in the small birds such as three different wrens including Superb Fairy-wren (Malurus cyaneus) and Variegated Fairy-wren (Malurus lamberti) and Australasian Pipit (Anthus novaeseelandiae).

The planted irrigated cotton crop was not sprayed with insecticide for 12 years after the increase in beneficial insect and bird numbers. Nest boxes have been installed in the conservation areas for the micro bats.  Fourteen species of insectivorous micro bats have been recorded on the farm since the rehabilitation work began. Stubble quail (Coturnix pectoralis) have been nesting in the conservation areas.

Figure 2. Log groins with planted native trees established on steep river bend near Boggabri through the Namoi Demonstration Reach Project (2007-14) coordinated by the NSW Dept of Primary Industries. (Photo R. Watson)

Further works undertaken nearby.  After seeing the improvement on our farm some adjoining landholders have begun fencing off their river areas and introducing rehabilitation measures on their farms. In one outstanding collective example, 120 kilometres of the Namoi Demonstration Reach Project was established by the NSW Dept of Primary Industries both upstream and downstream of Kilmarnock, from 2007 to 2014.  This This involved contractors, working with permission of a number of landholders, planting over eight thousand trees and shrubs along the river and constructing log groins at a badly eroding river bend near the Boggabri township.  These groins have worked well and have withstood a couple of small floods.  The trees planted on the steep banks have also established well (Fig. 2).


Figure 3. – Planted Phragmites saved the river bank from bush fire in 2017. (Photo R. Watson)

A major bushfire in 2017 spread across the river to the top of the banks on the Kilmarnock side of the river.  Because of the planted Phragmites on the river edge there was no damage done to the toe of the river bank (Fig 3) and we were able to bulldoze firebreaks to protect  the planted trees affected from the fire.)  However, a number of the old River Red Gums were badly burnt. Many of the very old hollow trees were killed by the fire but less hollow ones have begun to grow again, although this growth has been slowed by the present drought.

With the 2019 drought conditions the Namoi River has dried out, exposing the river bed.  This has given me a chance to observe the river bed.  I have been able to photograph and document the debris on the sand banks and the remaining water holes and show that there are now substantial amounts of hollow logs and debris (Fig. 4)  which can  provide good habitat for fish and water creatures when the stream is flowing.

Our family has purchased more land downstream on the Namoi River and we have implemented rehabilitation on the river banks, tree planting and conservation measures on those farms.

Contact.  Robyn Watson, Kilmarnock, Boggabri, NSW 2382, Australia; Tel: 02 67434576 Email: wjwatson@northnet.com.au

Figure 4. Hollow log and debris on riverbed provide fish habitat when river is flowing. (Photo R. Watson)

 

Recovering Murray-Darling Basin fishes by revitalizing a Native Fish Strategy – UPDATE of EMR feature

John Koehn, Mark Lintermans and Craig Copeland

[Update of EMR Feature: Koehn JD, Lintermans M, Copeland C (2014) Laying the foundations for fish recovery: The first 10 years of the Native Fish Strategy for the Murray‐Darling Basin, Australia. Ecological Management & Restoration, 15:S1, 3-12. https://onlinelibrary.wiley.com/toc/14428903/2014/15/s1]

Key words restoration, native fish populations, threatened species, Australia, Murray-Darling Basin

Figure 1. The construction of fishways can help restore river connectivity by allowing fish movements past instream barriers. (Photo: ARI.)

 Introduction. Fish populations in the Murray-Darling Basin (MDB), Australia, have suffered substantial declines due to a wide range of threats and there is considerable concern for their future. Given these declines and the high ecological, economic, social and cultural values of fish to the Australian community, there is a need to recover these populations. In 2003, a Native Fish Strategy (NFS) was developed to address key threats; taking a coordinated, long-term, multi-jurisdictional approach, focussed on recovering all native fish (not just angling species) and managing alien species. The strategy objective was to improve populations from their estimated 10% of pre-European settlement levels, to 60% after 50 years of implementation.

To achieve this the NFS was intended to be managed as a series of 10-year plans to assist management actions in four key areas; the generation of new knowledge, demonstration that multiple actions could achieve improvements to native fish populations, building of a collaborative approach, and the communication of existing as well as newly-acquired science. The NFS successfully delivered more than 100 research projects across six ‘Driving Actions’ in its first 10 years, with highlights including the implementation of the ‘Sea to Hume’ fishway program (restoring fish passage to >2 200 km of the Murray River, Fig 1), improved knowledge of fish responses to environmental water allocations, development of new technologies for controlling alien fish, methods to distinguish hatchery from wild-bred fish, creating a community partnership approach to ‘ownership’ of the NFS, and rehabilitating fish habitats using multiple interventions at selected river (demonstrations) reaches.  The NFS partnership involving researchers, managers, policy makers and the community delivered an applied research program that was rapidly incorporated into on-the-ground management activities (e.g. design of fishways; alien fish control, environmental watering; emergency drought interventions). The NFS largely coincided with the Millennium Drought (1997-2010) followed by extensive flooding and blackwater events, and its activities contributed significantly to persistence of native fish populations during this time.

Funding for the NFS program ceased in 2012-13, after only the first decade of implementation but the relationships among fishers, indigenous people and government agencies have continued along with a legacy of knowledge, development of new projects and collaborative networks with key lessons for improved management of native fishes (see http://www.finterest.com.au/).

Figure 2. Recreational fishers are a key stakeholder in the Murray-Darling Basin, with a keen desire to have sustainable fishing for future generations. (Photo: Josh Waddell.)

Further works undertaken. Whilst the NFS is no longer funded as an official project, many activities have continued though a range of subsequent projects; some are highlighted below:

  • Environmental water: development of fish objectives and implementation of the Basin Plan, northern MDB complementary measures, further investigation of mitigation measures for fish extraction via pumps and water diversions.
  • Fishways: Completion of sea to Lake Hume fishway program and other fishways such as Brewarrina
  • Community engagement: Continuation of many Demonstration (recovery) reaches and intermittent NFS Forums (Fig 2).
  • Recreational fishery management: engagement of anglers through the creation of the Murray Cod (Maccullochella peelii) fishery management group and OzFish Unlimited.
  • Threatened species recovery: success with Trout Cod (Maccullochella macquariensis)  (Fig 3) and Macquarie Perch (Macquaria australasica) populations, development of population models for nine MDB native fish species.
  • Knowledge improvement: research has continued, as has the publication of previous NFS research-related work.
  • Indigenous and community connection to fishes: development of the concept of Cultural flows, involvement in Basin watering discussions.

Figure 3. Trout Cod are a success story in the recovery of Australian threatened species. (Photo: ARI.)

Further results to date. The continued poor state of native fishes means there is a clear need for the continuation of successful elements of the NFS. There is need, however, for revision to provide a contemporary context, as some major changes have occurred over the past decade. The most dramatic of these, at least publicly, has been the occurrence of repeated, large fish kills (Fig 4). This was most evident in the lower Darling River in early 2019 when millions of fish died. The media coverage and public outcry followed the South Australian Royal Commission and two ABC 4Corners investigations into water management, highlighted that all was not well in the Murray-Darling Basin. Indeed, following two inquiries, political recommendations were made to develop a Native Fish Recovery Management Strategy (NFMRS), and a business case is currently being developed. The drought, water extraction and insufficient management efforts to support native fish populations, especially within a broader sphere of a ‘new’ climate cycle of more droughts and climatic extremes, have contributed to these fish kill events. For example, one of the necessary restoration efforts intended from the Basin Plan was to provide more water for environmental purposes to improve river condition and fish populations. Recent research, however, appears to indicate that flow volumes down the Darling River have generally decreased. There is also a continuing decline of species with examples such as Yarra Pygmy Perch (Nannoperca obscura), now being extinct in MDB, and the closely related Southern Pygmy Perch (Nannoperca australis) which is still declining. Monitoring of fish populations has indicated that they remain in poor health and the need for recovery may be even greater than in 2003. We need to act now.

While some of the legacy of the NFS has continued, there has been a loss of integrated and coordinated recovery actions that were a key feature of the NFS. This loss of a Basin-wide approach has resulted in some areas (e.g. small streams and upland reaches) being neglected, with a concentration on lowland, regulated river reaches. There has also been a shift from a multi-threat, multi-solution approach to recovery, to a narrower, flow-focussed approach under the Basin Plan. In addition, there has been the installation of infrastructure (known as Sustainable Diversion Measures) to ‘save’ water which may have deleterious impacts on fish populations (e.g. the impoundment of water on floodplains by regulators or the changed operations of Menindee Lakes on the Darling River).

A clear success of the NFS was improvements in community understanding of native fishes and their engagement in restoration activities. These community voices- indigenous, conservation, anglers, etc. have been somewhat neglected in the delivery of the Basin Plan. There has been ongoing fish researcher and stakeholder engagement, but this has been largely driven by enormous goodwill and commitment from individuals involved in the collaborative networks established through the NFS. While these efforts have been supported by many funding bodies and partners such as the Murray-Darlin Basin Authority, state and Commonwealth water holders and agencies and catchment management authorities, without true cross-basin agreement and collaboration the effectiveness of these efforts will be significantly reduced.

Figure 4. Fish kills have created great public concern and are an indication of the need for improved management of native fish populations. (Photo:Graeme McRabb.)

Lessons learned and future directions.  Native fish populations in the MDB remain in a poor state and improvements will not be achieved without continued and concerted recovery efforts. Moreover, a 5-year review of the NFS indicated that while the actions undertaken to that time had been positive, they needed to be a scaling up considerably to achieve the established goals.  Recovery actions must be supported by knowledge and the lessons learnt from previous experience.  Some fish management and research activities have continued under the auspices of the Basin Plan, but these have largely focussed on the delivery of environmental water, either through water buy-backs or improved efficiency of water delivery. A key requirement is therefore transparent and accurate measurement and reporting of how much flow has been returned to the environment, and how this may have improved fish populations. This remains problematic as evidenced by the recent inquiries into fish kills in the lower Darling River (and elsewhere) and the lack of available water accounting. Fish kills are likely to continue to reoccur and the lingering dry conditions across much of the Northern Basin in 2018-19 and climate forecasts have highlighted the need for further, urgent actions through an updated NFS.

The NFS governance frameworks at the project level were excellent and while some relationships have endured informally, there is a need for an overarching strategy and coordination of efforts across jurisdictions to achieve the improved fish outcomes that are required. The absence of the formal NFS thematic taskforces (fish passage, alien fishes, community stakeholder, demonstration reaches etc) and the absence of any overarching NFS structures means that coordination and communication is lacking, with a focus only on water, limiting the previously holistic, cross jurisdiction, whole-of-Basin approach. The priority actions developed and agreed to for the NFS remain largely relevant, just need revitalized and given the dire status of native fish, scaled up significantly.

Stakeholders and funding. The continuation of quality research and increased understanding of fish ecology, however, not have kept pace with the needs of managers in the highly dynamic area of environmental watering. The transfer of knowledge to managers and the community needs to be reinvigorated. Efforts to engage recreational fishers and communities to become stakeholders in river health are improving (e.g. OzFish Unlimited: https://ozfish.org.au; Finterest website: http://www.finterest.com.au/) but with dedicated, increased support, a much greater level of engagement would be expected.  Previously, the community stakeholder taskforce and Native Fish coordinators in each state provided assistance and direction, including coordination of the annual Native Fish Awareness week. Some other key interventions such as the Basin Pest Fish Plan have not been completed and recovery of threatened fishes have received little attention (e.g. no priority fish identified in the national threatened species strategy).  Funding for fish recovery is now piecemeal, inadequate and uncoordinated, despite the growing need. The $13 B being spent on implementation of the Basin Plan should be complemented by an appropriate amount spent on other measures to ensure the recovery of MDB fishes.

Contact information. John Koehn is a Principal Research Scientist at the Arthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, was an author the Murray-Darling Basin Native Fish Strategy and a member of various Native Fish Strategy panels and projects (Email:  John.Koehn@delwp.vic.gov.au). Mark Lintermans is an Associate Professor at Institute for Applied Ecology, University of Canberra, and was a member of various Native Fish Strategy panels and projects; (Email: Mark.Lintermans@canberra.edu.au). Craig Copeland is the CEO of OzFish Unlimited and a leading contributor to the development of the next stage of the Native Fish Strategy, the Northern Basin Complementary Measures Program and the 2017 MDB Native Fish Forum (Email: craigcopeland@ozfish.org.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

Piccaninnie Ponds Conservation Park, South Australia

Mark Bachmann

Key words: wetland restoration, Ramsar, rising springs, drainage, hydrology

Piccaninnie Ponds Conservation Park is situated 30 km south east of Mt Gambier in South Australia. For 15-20 years after the park was proclaimed in 1969, there was considerable local interest in trying to address previous changes that had been made to the hydrology of the wetland system.

Although it was protected, reserved and supporting a diverse suite of habitats and range of resident threatened species, Piccaninnnie Ponds was far from intact from a hydrological perspective. Prior to European settlement, water that discharged from the karst, rising-spring wetlands in the system flowed eastward across the State border into the Glenelg River Estuary, in far South West Victoria.

This is how the system remained until 1906, when the first of several attempts to drain the wetlands of Piccaninnie Ponds directly to the sea occurred. What ensued was a turbulent 9 year period during which the fishermen successfully lobbied to have the creek re-directed to the Glenelg River in 1915; a step which was ultimately unpopular with affected landholders and resulted in an alternative flow path again being cut to the sea two years later in 1917. Subsequent ad hoc drainage and development of portions of the wetland system continued and by the time the Piccaninnie Ponds Conservatioon Park was proclaimed in 1969, a new main artificial outlet drained the ponds directly to the sea.

The first attempts at advocacy to restore environmental flows to the Glenelg River in the 1970s and 80s to counter this long-term drying trend in the Park were unsuccessful, until the concept was revisited and a series of steps undertaken, starting in 2001, to achieve hydrological restoration. These steps culminated in the following actions.

 Fig. 1 – Stage 1 weir and fishway under construction in 2006.

Fig. 1,  Stage 1 weir and fishway under construction in 2006.

Actions taken to correct hydrology

  1. 2006 – Stage 1 weir and fishway constructed at Piccaninnie Ponds (Figure 1) regulated outflows on the artificial outlet. This had the effect of increasing inundation in a small area immediately upstream of the structure, under the direct influence of the weir pool created by the new structure, as shown in Fig 2.
  2. 2013 – The stage 2 weir and fishway upgrade (Fig 3) resulted in the structure height being lifted to increase future management flexibility, including providing the future ability to completely block outflows, should the option of re-instating the original flow path one day become a reality.

The stage 2 upgrade was completed at the same time as providing a new flow path to physically reconnect the isolated eastern and western basins at Piccaninnie Ponds. These wetlands had been separated for several decades by a combination of lower water levels, sand drift and the impact of the Piccaninnie Ponds Road. An aerial photographic view of the new flow path is shown in Fig 4.

These works within the original Conservation Park, have occurred in in a complementary way with those that have occurred in the neighbouring, newly reserved area at Pick Swamp, each contributing to the wider vision for restoration of this wetland complex.

Fig. 2. Drained condition of habitat in 2006

Fig. 2a. Drained condition of habitat upstream of the Stage 1 weir (prior to construction  in 2006).

Fig. 3. The upstream inundation and habitat change caused by the stage 1 weir, 2012.

Fig. 2b. The upstream inundation and habitat change caused by the stage 1 weir, 2012.

Results to date.

  • Increase in quality and area of available habitat for native freshwater fish, including the nationally threatened Dwarf Galaxias (Galaxiellla pusilla)
  • Protection of hydrological processes that support a wide range of other threatened species, from a number of taxonomic groups
  • A positive trajectory of change in the distribution of wetland habitats in the vicinity of the works (increased aquatic habitat and reversal of a drying trend that was causing terrestrialisation of vegetation communities)
  • Re-establishment of connectivity between the western and eastern wetlands in the Park for the first time in several decades
Figure 4 – The lifted and redesigned stage 2 weir and fishway on the main artificial outlet at Piccaninnie Ponds – upon completion in 2013.

Fig. 3. The lifted and redesigned stage 2 weir and fishway on the main artificial outlet at Piccaninnie Ponds – upon completion in 2013.

Fig 5a. Piccaninnie

Fig. 4a. Before works – in January 2003

Figure 5 – TOP – Before works image: January 2003. BOTTOM – Post-construction/restoration image: January 2014.

Fig, 4b. After construction/restoration – in January 2014.

Future directions. The works and outcomes described here were delivered by staff working for the South Australian Department of Environment, Water and Natural Resources (DEWNR)

  • Ongoing management of the works and associated ecological monitoring in Piccaninnie Ponds Conservation Park is managed by DEWNR
  • Nature Glenelg Trust staff continue to provide specialist ecological advice and monitoring for the site when required by the site manager, DEWNR

Acknowledgements. The outcomes of the restoration project described can be attributed to a wide range of people who, in addition to the author (see current contact details below), worked at the South Australian Department of Environment, Water and Natural Resources during the period described. DEWNR project ecologists overseeing the works described here include Ben Taylor (stage 1 weir) and Steve Clarke (stage 2 weir and associated works).

The project was generously funded and supported by a range of different grants and programs administered by the South Australian Government, Australian Government and the South East Natural Resources Management Board.

Contact. Mark Bachmann. Nature Glenelg Trust, PO Box 2177, Mt Gambier, SA 5290 Australia; Tel +61 (0)8 8797 8181; Mob+61 (0) 421 97 8181; Email: mark.bachmann@natureglenelg.org.au Web| www.natureglenelg.org.au

See also:

Bradys Swamp EMR short summary

Long Swamp EMR short summary

Brady Swamp wetland complex, Grampians National Park, Victoria

Mark Bachmann

Key words: wetland restoration, Wannon River, hydrology, drainage, Gooseneck Swamp

A series of wetlands associated with the floodplain of the Wannon River (Walker, Gooseneck, and Brady Swamps), situated approximately 12 km north east of Dunkeld in western Victoria, were partially drained from the 1950s onwards for grazing purposes (Fig 1). A portion of these wetlands was later acquired and incorporated into the Grampians National Park (and other peripheral reserves) in the mid-1980s, managed by Parks Victoria. However, the balance of the wider wetland and floodplain area remained under private ownership, creating a degree of uncertainty surrounding reinstatement of water regime – an issue that was left unresolved for over two decades.

Many years of planning work, including modelling studies and biological investigations by a range of organisations, never quite managed to adequately resolve the best way to design and progress wetland restoration work in this area. To address the impasse, at the request of the Glenelg Hopkins CMA in early 2013, Nature Glenelg Trust proposed a staged restoration trial process which was subsequently agreed to by landowners, neighbours, government agencies, and local community groups.

Figure 1. Image from the present day: showing artificial drains (red lines/arrows) constructed to drain Walker, Gooseneck and Brady Swamps, as it operated from the 1950s–2013.

Figure 1. Image from the present day: showing artificial drains (red lines/arrows) constructed to drain Walker, Gooseneck and Brady Swamps, as it operated from the 1950s–2013.

Trials and permanent works undertaken.

Initial trials. The restoration process began in August 2013 with the installation of the first trial sandbag weir structure to regulate the artificial drain at Gooseneck Swamp. Its immediate success in reinstating wetland levels led to similar trials being initiated at Brady Swamp and Walker Swamp (Fig. 2) in 2014.

Figure 2. The volunteer sandbagging crew at the artificial drainage outlet from Walker Swamp - August 2014.

Figure 2. The volunteer sandbagging crew at the artificial drainage outlet from Walker Swamp – August 2014.

Permanent works were ultimately undertaken to reinstate the breached natural earthen banks at Brady and Gooseneck Swamps (Figure 3), implemented by Nature Glenelg Trust in early 2015.

Figure 3a. Trial Structure on the Brady Swamp outlet drain in 2014

Figure 3b. The same view shown in Figure 3a, after the completion of permanent works in 2015

Results. The works have permanently reinstated the alternative, original watercourse and floodplain of the Wannon River, which now activates when the water levels in these wetlands reach their natural sill level. This is predicted to have a positive impact on a wide range of flora and fauna species.

Monitoring is in place to measure changes to vegetation and the distribution and status of key fauna species, such as waterbirds, fish and frogs. Due to drought conditions experienced in 2015, to is too early to describe the full ecological impact of the works at this time.

4. Gooseneck Swamp in Sept 2014: the second season of the restoration trial, just prior to the implementation of permanent restoration works

Figure 4. Gooseneck Swamp in Sept 2014: the second season of the restoration trial, just prior to the implementation of permanent restoration works

Lessons learned. The success of these trials has been based on their tangible ability to demonstrate, to all parties involved, the potential wetland restoration outcome for the sites; made possible by using simple, low-cost, impermanent methods. To ensure the integrity of the trial structures, the sandbags used for this purpose are made of geotextile fabric, with a minimum field service life of approximately 5 years.

The trials were critical for building community confidence and collecting real operational data for informing the development of longer-term measures to increase the depth and duration of inundation.

A vital aspect of the trials has been the level of community participation, not only at the sandbagging “events”, but also the subsequent commitment to ecological monitoring, for helping evaluate the biological impacts of hydrological reinstatement. For example, the Hamilton Field Naturalists Club has been undertaking monthly bird monitoring counts that are helping Nature Glenelg Trust to develop a picture of the ecological value of these wetlands and their role in the wider landscape, including the detection of international migratory species.

Acknowledgements. Project partners include Parks Victoria, Hamilton Field Naturalists Club, the Glenelg Hopkins CMA, Macquarie Forestry and other private landholders. Volunteers from several other groups have also assisted with the trials. Grant funding was generously provided by the Victorian Government.

Contact. Mark Bachmann, Nature Glenelg Trust, PO Box 2177, MT GAMBIER, SA 5290 Australia. Tel +61 8 8797 8181, Mob 0421 97 8181; Email mark.bachmann@natureglenelg.org.au. Web| www.natureglenelg.org.au

See also:

Long Swamp EMR short summary

Picanninnie Ponds EMR short summary

Dewfish Demonstration Reach: Restoring native fish populations in the Condamine Catchment

Key words: native fish, riparian habitat, fish passage, aquatic habitat, Native Fish Strategy

The Dewfish Demonstration Reach is a 110 kilometre stretch of waterway in the Condamine catchment in southern Queensland consisting of sections of the Condamine River, Myall Creek and Oakey Creek near Dalby. The Reach was established in 2007 with the purpose of promoting the importance of a healthy river system for the native fish population and the greater river catchment and demonstrating how the restoration of riverine habitat and connectivity benefits native biodiversity and local communities. Landholders, community groups, local governments and residents have worked together to learn and apply new practices to improve and protect this part of the river system.

The purpose of the project is to demonstrate how the restoration of riverine habitat and connectivity benefits native biodiversity and promote the importance of a healthy river system for native fish and the greater river catchment. The goal is to restore native fish populations to 60% of pre-European settlement levels and improve aquatic health within the Reach.

Image 3 - Adding structural timber to Oakey Creek

Fig 1. Adding structural timber to Oakey Creek

Image 4 - Installing a fish hotel into Oakey Creek

Fig 2. Installing a fish hotel into Oakey Creek

Works undertaken. A range of activities to improve river health and native fish communities have been undertaken primarily at seven key intervention sites within the Dewfish Demonstration Reach. These include:

  • Re-introduction of large structural habitat at five sites, involving the installation of 168 habitat structures consisting of trees, fish hotels, breeding pipes and Lunkers (simulated undercut banks).
  • Improvement of fish passage (by more than 140 km) with the upgrade of the fishway on Loudoun Weir and the installation of two rock-ramp fishways on crossings in Oakey Creek.
  • Ongoing management of pest fish, involving carp angling competitions, carp specific traps, electrofishing and fyke nets.
  • Rehabilitation of the riparian vegetation over 77 km of the Reach using stock exclusion fencing, off-stream watering points, weed control and replanting of native vegetation. In Dalby, a 1 metre wide unmown buffer was established on the banks Myall Creek.

Twice-yearly monitoring using a MBARCI model (multiple-before-after-reference-control-intervention) was undertaken to detect the local and reach-wide impacts of the intervention activities. Surveys involved sampling of the fish assemblage at fixed sites and assessment of the instream and riparian habitat.

Image 5 - Wainui crossing before the fishway

Fig. 3 Wainui crossing before the fishway

Image 6 - Wainui crossing after installation of the rock-ramp fishway

Fig 4. Wainui crossing after the installation of the rock ramp fishway

Results. The surveys indicated many of the intervention activities had a positive impact. The fish assemblage and riparian habitat improved at all intervention sites in the Dewfish Demonstration Reach since rehabilitation activities commenced.

The fish assemblages at introduced habitat structures were very similar to those found on natural woody debris, suggesting the introduced habitat is functioning well as a surrogate.

There were significant increases in the abundance of larger fish species, including Golden Perch (Macquaria ambigua) (up to 5-fold), Murray Cod (Maccullochella peelii peelii) (from absent to captured every survey), Spangled Perch (Leiopotherapon unicolor) (up to 9-fold) and Bony Bream Nematolosa erebi (up to 11-fold) in intervention sites following re-snagging. Murray Cod and Golden Perch are now consistently being caught from introduced woody structures and local anglers are reporting that the fishing has improved greatly. Despite this increase there is still limited evidence of recruitment in the area. There have also been small increases in Eel-tailed Catfish (Tandanus tandanus) and Hyrtls Tandan (Neosilurus hyrtli) abundances and a limited amount of recruitment has been observed for these species.

The abundance of smaller native fish has improved significantly in response to the intervention activities undertaken, especially where bankside and instream vegetation was improved. In Oakey Creek Carp Gudgeon (Hypseleotris spp.) abundance increased 1200-fold, Murray-Darling Rainbowfish (Melanotaenia fluviatilis) increased 60-fold and the introduced species Mosquitofish (Gambusia holbrooki) increased 9-fold following intervention activities.

Establishment of a bankside unmown buffer on Myall Creek has enabled natural regeneration of vegetation and resulted in significant increases in aquatic vegetation and native trees. This has led to substantial increases in the smaller bodied native fish assemblage, including a 3-fold increase in Bony Bream, 237-fold increase in Carp Gudgeon, 60-fold increase in Murray-Darling Rainbowfish and a 35-fold in the introduced Mosquitofish.

The abundance of pest fish remains low, except for Mosquitofish which have increased in abundance with the improvements in the aquatic vegetation. There is little evidence of Carp recruitment (Cyprinus carpio), suggesting active management may continue to suppress the population and minimise this species impacts in the Reach.

Image 1 - Myall Creek prior to restoration

Fig 5.  Myall Creek prior to restoration

Image 2 - Myall Creek after restoration

Fig 6. Myall Creek after restoration

Lessons learned and future directions. Improvements of the waterway health and ecosystems can lead to positive responses from native fish populations.

  • Targeting rehabilitation activities to specific classes of fish has been very effective.
  • Introducing habitat structures has been effective for larger fish, and
  • Re-establishing healthy bankside and aquatic vegetation has been vital in boosting the abundance of juveniles and smaller species.

Improvements in the extent of aquatic vegetation have unfortunately also resulted in increased numbers of the introduced pest, Mosquitofish. However, the overall benefits to native fish far outweigh impacts from the increase in the Mosquitofish population.

Stakeholders and Funding bodies. A large number of stakeholders have been involved in this project. The project’s success is largely due to the high number of engaged, involved and committed stakeholders. Without this broad network, costs to individual organizations would be higher and strong community support less likely.

Major funding has been provided by the Murray Darling Basin Authority, Condamine Alliance, Queensland Department of Agriculture and Fisheries and Arrow Energy.

 

Contact. Dr Andrew Norris, Senior Fisheries Biologist, Queensland Department of Agriculture and Fisheries, Bribie Island Research Centre, PO Box 2066, Woorim, QLD 4507; Tel (+61) 7 3400 2019; and Email: andrew.norris@daf.qld.gov.au

READ MORE:

Finbox demonstration reach toolbox: http://www.finterest.com.au/finbox-a-demonstration-reach-toolbox/

Native Fish Strategy – first 10 years. http://onlinelibrary.wiley.com/enhanced/doi/10.1111/emr.12090

Demonstration reaches – Looking back, moving forward http://onlinelibrary.wiley.com/enhanced/doi/10.1111/emr.12092

Monitoring in demonstration reaches https://site.emrprojectsummaries.org/2014/01/25/establishing-a-framework-for-developing-and-implementing-ecological-monitoring-and-evaluation-of-aquatic-rehabilitation-in-demonstration-reaches/

 

Twelve years of healing: Rehabilitating a willow-infested silt flat – Stormwater Management.

Alan Lane

Key words: urban stream, erosion, siltation, soft engineering, head wall

Introduction: Popes Glen Creek is a small permanent stream rising close to the centre of the township of Blackheath, NSW, Australia. Its upper catchment (10 ha) comprises low-permeability urban development, roadways, shops and parklands.

The funneling of runoff from the low-permeability catchment into the headwaters of Popes Glen Creek resulted in intense and destructive runoff after rain, carrying down large and small debris, depositing sheets of silt, uprooting or burying vegetation, causing erosion of the creek banks and threatening to undermine the head wall of the silt flat downstream. This resulted in the formation of a 1 ha silt flat at the headwaters of the creek, covered with dense infestations of mature Crack Willow (Salix fragilis), Purple Ossier (S. purpurea) and mid-storey and ground-layer weeds. This has been revegetated as a permanent wetland as described in a previous summary (https://site.emrprojectsummaries.org/2015/02/22/)

This summary describes the runoff management aspects of the project, where the aims were:

  1. to reduce the impact of runoff
  2. to reduce the incursion of silt
  3. to remediate the main channel
  4. to stabilise the head wall.
Fig 1: Notched weir diverting water towards sedimentation pond.

Figure 1: Notched weir diverting water towards sedimentation pond.

Figure 2: Sedimentation pond

Figure 2: Sedimentation pond

Works carried out:

1. Diversion of part of the flow and capturing sediment. A diversion channel was constructed with flow regulated by a notched weir in the main stream. This diverts approximately half the volume of the flow into a sedimentation pond were silt is captured, reducing the quantity deposited downstream (Figures 1 and 2).

2. Construction of low-impact detention cells. “Soft engineering” detention cells constructed across the silt flat from coir logs and woody debris found on site retain and slow the release of flow, dispersing it across the silt flat and raising the water table, suppressing weeds and supporting the vegetation of the created wetland (Figures 3 and 4).

3. Elimination of the highly incised main channel. Natural debris falling into the main channel creates a series of small pondages. These retain and slow the flow and allow overflow to disperse across the silt flat. (Figure 5).

4. Protection of the creek banks. Dense plantings of deep-rooted swamp vegetation e.g. Red-fruited Saw Sedge (Gahnia sieberiana) and Black Wattle (Callicoma serratifolia) (Figure 6), and loosely woven structures constructed from woody debris (Figure 7) protect creek banks and silt flat from erosion and scouring.

5. Stabilisation of the headwall. Contractors employed with funds from the Environmental Trust have constructed a major structure with railway sleepers and rock armouring to stabilise the head wall (Figures 8 and 9).

Figure 3: Volunteers building a detention cell from woody debris found on site.

Figure 3: Volunteers building a detention cell from woody debris found on site.

Figure 4: Raised water table enabled wetland sedges (Carex gaudichaudiana and Eleocharis sphacolata) to displace Creeping Buttercup (Ranunculus repens).

Figure 4: Raised water table enabled wetland sedges (Carex gaudichaudiana and Eleocharis sphacolata) to displace Creeping Buttercup (Ranunculus repens).

 

Lessons learned and future directions:  This project is on track to replace the forest of willows with wetland vegetation, transform a highly incised creek and weed-infested silt flat into a healthy Upper Blue Mountains Swamp – an endangered ecological community scheduled under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999.

The volunteer group will continue working with Council and contractors to complete the planting program and to monitor the evolution of the site, including its vegetation, water quality and colonisation by macroinvertebrates, birds and frogs.

Stakeholders and funding bodies: This work is supported by a grant from the Government of New South Wales through its Environmental Trust and by the Blue Mountains City Council,  which also oversaw the engineering works. All photographs: Alan Lane and Paul Vale.

Figure 5: A natural pondage formed when debris was allowed to remain in the stream.

Figure 5: A natural pondage formed when debris was allowed to remain in the stream.

Figure 6: Dense plantings of Black Wattle (Calicoma serratifolia) and Gahnia (Gahnia sieberiana) protect creek banks from erosion.

Figure 6: Dense plantings of Black Wattle (Callicoma serratifolia) and Gahnia (Gahnia sieberiana) protect creek banks from erosion.

Figure 7: Volunteers using woody debris to protect the silt flat from scouring.

Figure 7: Volunteers using woody debris to protect the silt flat from scouring.

Figure 8: Part of the original head wall approximately 3 m high and 20 m wide.

Figure 8: Part of the original head wall approximately 3 m high and 20 m wide.

Figure 9:  Part of structure constructed to stabilise the head wall.

Figure 9: Part of structure constructed to stabilise the head wall.

Contact information: Dr Alan Lane, Coordinator Popes Glen Bushcare Group, PO Box 388, Blackheath NSW 2785, Australia. Tel: +61 2 4787 7097; Paul Vale, Deputy Coordinator Popes Glen Bushcare Group, 81 Prince Edward St, Blackheath NSW 2785, Australia. Tel: +61 2 4787 8080; and Ray Richardson, Chairman of Steering Committee, Environmental Trust Grant 2011/CBR/0098. Tel: +61 2 4759 2534.

Twelve years of healing: Rehabilitating a willow-infested silt flat – Revegetation

Alan Lane

Key words: weed management, National Park, headwall, instability, Salix

The site: Popes Glen Creek is a small permanent stream rising in Memorial Park, Blackheath New South Wales, Australia. It flows through Popes Glen Bushland Reserve and the Greater Blue Mountains World Heritage Area (GBMWHA), joining the Grose and Hawkesbury/Nepean River systems. The upper catchment drains a significant sector of the urban township of Blackheath.

The problem: Decades of erosion from surrounding unsealed roads resulted in a 1ha silt flat forming at the headwaters of the creek and terminating in a highly incised headwall 3m high and 20m wide. Upstream, the silt flat and severely braided creek were populated by a dense forest of mature, multi-trunked specimens of Crack Willow (Salix fragilis), as well as thickets of Purple Ossier (S. purpurea), Small-leaf Privet (Ligustrum spp.), Holly (Ilex aquifolium), Cotoneaster (Cotoneaster spp.) and immature S. fragilis. There was also a ground layer of Montbretia (Crocosmia x crocosmiiflora), Blackberry (Rubus fruticosus agg), English Ivy (Hedera helix), Creeping Buttercup (Ranunculus repens) and Honeysuckle (Lonicera japonica).

This dense and complex infestation of weeds threatened to spread downstream into susceptible remote areas of the GBMWHA, where it would rapidly become extremely difficult to remove and would ultimately threaten the Grose and Hawkesbury-Nepean River systems.

Fig 1. Feb 2005 - the creek bank, dominated by weeds prior to work.

Fig 1. Feb 2005 – the creek bank, dominated by weeds prior to work.

Fig 2. Sept 2014 - same site nearly 10 years later, showing established plantings and some natural regeneration.

Fig 2. Sept 2014 – same site nearly 10 years later, showing established plantings and some natural regeneration.

Works carried out: Phase 1: 2002 – 2008  In 2002, the Pope’s Glen volunteer bushcare group, supported by Blue Mountains City Council and funding from the Urban Run-off Control Program, established trial plantings on four sites (100m2 each) to identify a limited range of local riparian and wetland species and the planting techniques best suited to revegetating and stabilising the silt flat. The species included Red-fruit Saw-sedge (Gahnia sieberiana), three teatree species (Leptospermum lanigerum, L. polygalifolium, and L. juniperinum), Broad-leaved Hakea (Hakea dactyloides), and three ferns (Blechnum nudum, B. watsii and Cyathea australis).

A 3-year grant from the Environmental Trust (2005-2008) then enabled a program of weed removal and replanting, encompassing the upstream half of the silt flat and expanding the list of plant species to about 30.

The weeds were removed progressively in a patchwork to preserve the stability of the silt. The willows were killed by stem injection and felled when dead. Over these 3 years, the volunteer group planted approximately 7000 plants and carried out approximately 1200 hours of site maintenance. This has resulted in a diverse and resilient wetland community, with high levels of plant establishment from both planting and from natural recruitment (Figs 1 and 2).

Phase 2: 2012 – 2018 At the commencement of this phase, stability of the downstream portion of the silt flat and headwall was dependent upon the integrity of the roots of the remaining dense stands of weeds. These could be removed only as part of an integrated program of works to stabilise the silt and the headwall. A second grant from the Environmental Trust (2012-2018) is enabling an integrated, 6-year program of stabilisation, restoration and revegetation to be carried out by a team of experienced contractors, using both “soft” and “hard” engineering strategies.

The volunteer group is responsible for on-going site maintenance, photography, monitoring surface water quality and water table depth and quality, and for surveying vegetation, macro-invertebrates, frogs, birds and stygofauna.

Overall results. The formerly highly degraded silted flat is now a thriving community of wetland and riparian vegetation, home to a rich diversity of small birds, dragonflies and mayflies. Frogs are beginning to populate the site. Water quality has been significantly improved, with up to 85% of faecal coliforms and 75% of nitrate-N removed in the wetland. This improves the water quality in Popes Glen Creek and reduces the pollutant load into the GBMWHA.

Fig 3. Feb 2013 - a portion of the headwall viewed from downstream. (Plunge pool approx.3m below. (Image Damon Baker www.nomadgraphics.com.au).

Fig 3. Feb 2013 – a portion of the headwall viewed from downstream. (Plunge pool approx.3m below. (Image Damon Baker http://www.nomadgraphics.com.au).

Fig 4. Nov 2014 - same site showing heavy retaining wall and spillway now constructed. (Plunge pool has been stabilised with rock armouring.)

Fig 4. Nov 2014 – same site showing heavy retaining wall and spillway now constructed. (Plunge pool has been stabilised with rock armouring.)

Lessons learned and future directions: This is an example of how an apparently overwhelming challenge can be tackled by a dedicated group of volunteers with critical mass, commitment and longevity, provided that the group has support from a body such as a local Council and that it can raise funds to employ skilled assistance as needed. It is anticipated that the ambitious program of rehabilitating the extensive and highly degraded silt flat will be completed within the life of the present grant.

Stakeholders and funding bodies: This work is supported by a grant from the Government of New South Wales through its Environmental Trust and by the Blue Mountains City Council. Unless otherwise stated, photographs have been provided by Alan Lane and Paul Vale.

Contacts: Dr Alan Lane, Coordinator Popes Glen Bushcare Group, PO Box 388, Blackheath NSW 2785, Australia. Ph +61 2 4787 7097; Paul Vale, Deputy Coordinator Popes Glen Bushcare Group, 81 Prince Edward St, Blackheath NSW 2785, Australia. Ph +61 2 4787 8080; and Ray Richardson, Chairman of Steering Committee, Environmental Trust Grant 2011/CBR/0098. Ph +61 2 4759 2534.

Cooks River Naturalisation, Sydney, NSW Australia

By Dan Cunningham

Key words: riparian rehabilitation, revegetation, reconstruction

document

A reach of the Cooks River prior to and after naturalisation

A reach of the Cooks River prior to and after naturalisation

Sydney Water have undertaken a project to convert 1.1km of concreted sections of the Cooks River, Sydney Australia, to a more natural state, substantially improving their potential for aquatic function and the provision of services to surrounding residential areas.

The problem and its causes. Seven kms of the highly urbanised Cooks River were concrete lined in the 1940s in an effort to alleviate flooding and reduce water pollution. Since that time the natural values of the river have declined due to pollution and lack of riparian remnant vegetation.

Community interest in the quality of the environment had increased since the 1940s and, the structure of the concrete began to significantly deteriorate, in 2014 Sydney Water removed sections of deteriorated concrete and undertook environmental rehabilitation of parts of the riparian zone.

Fig 2. Cooks River Naturalisation sites

Fig 2. Cooks River Naturalisation sites

What we did. Between 2007 and 2013 Sydney Water carried out a masterplanning exercise that included asset inspections, hydraulic analysis, stakeholder consultation and concept design development; in order to identify sites along the river that were suited to renewal and naturalisation (Fig 2).

There was little adjacent native vegetation on which to base the design of the revegetation work, but local botanical surveys had resulted in a conceptual map of the catchment’s pre-existing ecological communities, which allowed the project to select species suited to four different habitat types:

  • Freshwater and Brackish Swamp – Lower to mid bank (non- tidal reach) and constructed wetland
  • Clay Plain Scrub Forest – mid bank to upper bank and over bank areas (reference – Third Avenue remnant)
  • Turpentine Ironbark Forest – Selected larger trees
  • Coastal Saltmarsh – Lower to mid bank (tidal reaches) and saltmarsh benches (reference Gough Whitlam Park and Wolli Ck)
Fig 3. Presumed ecological communities prior to clearing

Fig 3. Presumed ecological communities prior to clearing

Fig. 4. Profile of bank treatment

Fig. 4. Profile of bank treatment

Fig 5. Concrete lining of

Fig 5. Concrete lining of

 Results. The project resulted in the reconstruction of a diversity of native riparian habitat types and improved connectivity for biota between reaches of the river that were previously disconnected. This resulted in massive aesthetic improvement, with local residents conveying much improved local area pride and positivity. The project provides a social amenity, with the provision of pathways, seating, interpretive signage and provides an opportunity for local communities to reinstate a sense of place and reconnect with each other in the context of a natural river. In addition it represents value for money considering that longer asset life produced by the natural system.

Fig 6. Works inlcuded floodways devoid of trees.

Fig 6. Works inlcuded floodways devoid of trees.

Fig 7. Native vegetation now stabilising the banks.

Fig 7. Native vegetation now stabilising the
banks.

Acknowledgement: This summary was first presented to the Symposium ‘Reubilding Ecosystems’ held at the Teachers’ Federation Conference Centre, Sydney by the Australian Association of Bush Regenerators (AABR)

Contact: Dan Cunningham – Program Lead, Waterways Sydney Water, Email: <daniel.cunningham@sydneywater.com.au>

Websites:

http://www.sydneywater.com.au/SW/water-the-environment/what-we-re-doing/current-projects/stormwater-management/stormwater-naturalisation/index.htm

http://www.sydneywatertalk.com.au/crbnp/

WATCH THE VIDEO: from symposium ‘Rebuilding Ecosystems: What are the Principles?’ Teachers’ Federation Conference Centre, Sydney, November 13th, 2014, Australian Association of Bush Regenerators (AABR).

 

Assessing the effectiveness of Integrated Pest Management in Queensland

Key words: Integrated Pest Management, pest fish control, Native Fish Strategy

Threats and Impacts: Carp (Cyprinus carpio) are believed to impact on native fish communities by increasing turbidity, up-rooting delicate shallow-rooted vegetation, competing with native fishes and other aquatic fauna for food and space, and indirectly promoting the development of toxic algal blooms.

All of the currently available methods for Carp control have limitations. Integrated Pest Management (IPM) involves the application of a range of technologies applied simultaneously, and focussing on achieving broader objectives (e.g. improved habitat) rather than simply reducing pest numbers.

Broad aim and specific objectives: The objectives of this project were to apply a range of Carp control techniques, as an integrated package, to:

  • intensively reduce Carp at a particular location, and measure the response;
  • achieve a significant reduction in damage caused by Carp using existing techniques; and,
  • demonstrate to the community the commitment to on-ground control.

The study was conducted at four lagoon sites, two in the Condamine River catchment, and two in the Macintyre river catchment.

Methods: One lagoon in each catchment was selected as an experimental site for intensive carp removal, and the other was used as a reference site which received no carp treatment.

Each site was sampled on eight occasions for the following response variables: water quality (temperature, pH, conductivity, turbidity, dissolved oxygen, light penetration, available forms of nitrogen and phosphorus); phytoplankton biovolume and diversity; zooplankton biomass and diversity; benthic macroinvertebrate abundance and diversity; native fish abundance, biomass and diversity; carp abundance, biomass and size distribution; and abundance of piscivorous birds and turtles.

One sampling event was conducted before the carp reduction treatment and a further seven samples were performed after Carp reduction. Carp removal employed a variety of methods based on boat electrofishing, gill nets, fyke nets, angling, commercial-scale netting and traps, and screens to prevent re-entry of Carp.

Figure 1: electrofishing during carp removal at rainbow lagoon. (Photo courtesy Peter Gehrke)

Figure 1: electrofishing during carp removal at rainbow lagoon. (Photo courtesy Peter Gehrke)

Figure 2: Researcher Sarah St Pierre live picking macroinvertebrates (Photo courtesy of Nissa Murphy)

Figure 2: Researcher Sarah St Pierre live picking macroinvertebrates (Photo courtesy of Nissa Murphy)

Findings: In Rainbow Lagoon (one of the experimental sites), Carp removal achieved an estimated 51% reduction in abundance and 43% biomass reduction, compared with 41% abundance and 33% biomass reductions in Warra Lagoon (the other experimental site). Reduction of Carp biomass by approximately 30 kg per ha allowed a threefold increase of more than 90 kg per ha in native fish that are eaten by larger fish species and fish-eating birds.

The size and weight of Carp removed differed markedly between Warra Lagoon and Rainbow Lagoon. Rainbow Lagoon had large numbers of small Carp, while Warra Lagoon had relatively large numbers of big Carp, with relatively few small individuals. The differences in Carp populations between lagoons are likely to result in different ecosystem responses over time.

Boat electrofishing was the most effective method of Carp removal used; fyke nets were the second most effective method, while the number of Carp removed by angling was far lower than other methods.

A succession of ‘transient’ responses to Carp reduction was observed in treatment lagoons. Whilst the exact nature of succession differed between lagoons, the generalised pattern following Carp reduction was evidenced as (i) an increase in biomass of large zooplankton; (ii) an increase in abundance of benthic macroinvertebrates; and (iii) increased biomass of gudgeons (Hypseleotris spp.) and Bony Herring (Nematalosa erebi).

These results suggest that of the full set of potential ecosystem responses to Carp reduction, only a subset may be demonstrated in individual locations because of the influence of local drivers and constraints. Due to a range of factors, the environmental responses of several variables, including water quality, macrophytes, zooplankton and macroinvertebrates, could not be linked to Carp control.

Lessons learned and future directions:Modest reductions in Carp biomass can provide significant benefits for native fish and, if continued, may be expected to translate into longer-term increases in native fish populations.

  • Carp in turbid wetlands interact strongly with native fish through pelagic food web pathways involving zooplankton, as well as benthic macroinvertebrate pathways.
  • Carp reduction has the potential to contribute significantly to restoring populations of native fish by increasing food availability.
  • Environmental outcomes of Carp reduction include direct conservation benefits to native fish, potential increases in popular recreational species and improved aquatic ecosystem health.
  • Piscivorous fish (e.g. Murray cod, Maccullochella peelii) are likely to have increased prey availability as a result of Carp reduction.
  • Improving native fish populations in key wetlands by reducing Carp biomass may strengthen the value of permanent lagoons as drought refuges for native fish.

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

Contact: Sarah St Pierre, SMEC. Tel: + 61 (07) 3029 6600.

Link: http://www.finterest.com.au/wp-content/uploads/2013/07/MD923%20Integrated%20pest%20management%20QLD.pdf