Category Archives: Integrating ecosystems & industries

Developing a population model for Murray Cod (Macculochella peelii) to address key management actions

Key words: Population model, Murray Cod, fisheries management, Native Fish Strategy

Threats and Impacts: Murray Cod (Macculochella peelii) is a key recreational fishing target species as well as being a nationally listed threatened species (Fig 1). Management action is required to rehabilitate populations of this species in the Murray-Darling Basin. Fish population models are a simple description of a fishes life cycle and try to incorporate any external factors that may affect the individual and population. The main use of these models is to hypothetically assess the impacts (negative or positive) of different management or environmental scenarios to provide managers with predictive power to better manage fish populations. Prior to this project no such model had been created for any species in the Murray-Darling Basin.

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

  • Develop a computer model (or models) to represent the population dynamics of Murray Cod under alternative management options.
  • Develop various management scenarios in relation to size and bag limits and potential recovery times from overfishing, fish kills and other management or environmental scenarios which may affect Murray Cod populations.
  • Document the findings of this work, and the implications for developing management options for Murray Cod and the research on Murray Cod biology and ecology required for improving the model (or models).

Methods: A review was undertaken initially to summarise relevant scientific, management, angler and aquaculture literature on:

  • Murray Cod biology and ecology;
  • Management options for Murray Cod and similar fish in the Murray-Darling Basin and elsewhere; and,
  • Population and other (climate and GIS) models for fish or other fauna which will allow alternative management options to be tested;

Conceptual models of Murray Cod biology and ecology were then developed, and information gaps which needed to be addressed were identified. A workshop was also held to bring together a range of technical experts and jurisdictional representatives (SA, QLD, VIC, NSW, ACT and Commonwealth) to determine the key management actions to address the sustainable management of Murray Cod as well as the knowledge requirements necessary to develop the appropriate model(s) to assess the key management actions.

A population model for Murray Cod was developed as a key output of this project, which would enable different management actions/scenarios to be assessed and compared on the basis of their relative benefit and level of risk.

Figure 1 - This project developed a population model for Australia's largest freshwater fish species, Murray Cod . (Photo courtesy of Jamin Forbes)

Figure 1 – This project developed a population model for Australia’s largest freshwater fish species, Murray Cod . (Photo courtesy of Jamin Forbes)

Figure 2 - An example of graphical outputs from a fishing scenario. (Courtesy of Charles Todd.)

Figure 2 – An example of graphical outputs from a fishing scenario. (Courtesy of Charles Todd.)

Findings: Modelled management scenarios for Murray Cod indicate that the risk to populations can be reduced substantially by appropriate changes to the size limits on angler take. The  implementation of a slot size (minimum and maximum size limit) that protects both smaller and larger fish reduced population risk considerably. While habitat changes are difficult to quantify, it was illustrated that reductions in amount of habitat can place additional risk on populations, particularly when combined with angler take. Importantly, the collective impacts of less recognised threats such as thermal pollution, fish kills and mortalities to larvae over weirs and losses into irrigation off-takes can be explored and need to be recognised as having the potential to contribute significantly to mortalities at certain sites.

Lessons learned and future directions: The methods outlined in this study offer a formalised, rational, modelling approach that can form the basis for the assessment and prioritisation of management options for Murray Cod to minimise the risk to populations. Such modelling also highlights data gaps and monitoring requirements and can become an integral part of the conservation and fishery management process (Fig 2) and provides a tool for exploring the outcomes of management scenarios at both the regional and local scale. The modelling process has helped facilitate interagency Murray Cod management and emphasises the need for coordination between fishery managers and water/environmental protection/conservation agencies.

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

Contact: Dr. Charles Todd, Arthur Rylah Institute, (02) 60519920, Charles.Todd@depi.vic.gov.au, 23 Brown St, Heidelberg, Victoria, Australia, +61 3 9450 8600.

Link: http://www.mdba.gov.au/sites/default/files/pubs/MC-Final-Report.pdf

Understanding the effects of environmental flow allocations on the lateral movements of native fish in the Barmah-Millewa Forest

Key words: Environmental flows, floodplain wetlands, fish migration, regulators, Native Fish Strategy. 

Passage to and from floodplain wetland areas is very important for native fish, as some species utilise these areas for spawning, feeding and recruitment (survival of fishes from eggs to reproductive stage). Regulators were originally installed in the Barmah-Millewa Forest (BMF) to keep water out during the agricultural irrigation season (Fig 1), however such regulators are now thought to adversely effect the lateral movements of native fish. 

Broad aim and methods. This project aimed to investigate the lateral movements of native fish during normal river discharges and during an environmental water allocation (EWA) in order to determine the impact of regulators on native fish movements in the BMF. 

Sampling was conducted within a number of key fish species in the BMF. Electrofishing was used to determine the presence and abundance of species within habitats sampled (Fig 2). Egg samples were taken from adult individuals to understand whether fish in regulated offstream habitats developed and spawned naturally. Tagging (radio-telemetry and t-bar tagging) was used to monitor movement behaviour, and drum, fyke, frog and larval nets were used to determine which species are using the waterways sampled and to investigate whether movement is influenced by flow. Water quality parameters were also recorded. 

Figure 1. Regulator on Gulpa Creek. (Photo courtesy Matthew Jones, ARI)

Figure 1. Regulator on Gulpa Creek. (Photo courtesy Matthew Jones, ARI)

Figure 2. Golden perch fitted with radio transmitter. (Photo courtesy Matthew Jones, ARI.)

Figure 2. Golden perch fitted with radio transmitter. (Photo courtesy Matthew Jones, ARI.)

 

Findings: Results suggest that movement between the Murray River and wetland creeks occurs on a regular basis in unregulated parts of the BMF. Fish generally respond to changes in flow by moving into these creeks on rising flows and returning on falling flows. 

In regulated systems, fish generally approached the regulator on falling flows, presumably trying to return to the Murray River like fish in unregulated creeks, but being prevented from returning by the regulators they therefore remained stranded downstream. Movements back to the Murray River were only possible for a few large-bodied individuals during flood conditions when regulators were drowned-out and water velocities and turbulence reduced to the extent that such fish could escape. 

Rising water levels associated with the EWA induced fish to move into unregulated wetland creeks and fish generally occupied these creeks for the duration of the EWA. Results indicated that fish remain in these creeks for as long as they are inundated to spawn and feed. Modelled data suggest that without the EWA, flows would have dipped below bankfull several times in late 2005, which, based on previous movements, would most likely have resulted in fish leaving wetland creeks, possibly interrupting feeding and/or spawning activities. 

Lessons learned and future directions: Results from this project will be used to guide the use of off-channel regulators to facilitate movement of native fish to and from off-channel habitats to promote spawning and reduce the likelihood of fish being stranded in drying off-river habitats. The results of this project will also provide information for better targeting of environmental water releases for native fish. 

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

Contacts: Dr Matthew Jones, Arthur Rylah Institute for Environmental Research (ARI). (03) 9450 8600, matthew.jones@depi.vic.gov.au

Link: http://www.mdba.gov.au/sites/default/files/pubs/MDBA-13067-Barmah-Millewa-Forestv2.pdf

Slopes2Summit Bushlinks Project

Keywords – landscape, connectivity, restoration, revegetation, NSW southwest slopes

The Slopes2Summit (S2S) Bushlinks project commenced in August 2012 and is in the first stage of implementing on-ground works to build landscape-scale connectivity across private lands in the southwest Slopes of NSW – from the wet and dry forest ecosystems of the upper catchment and reserves to the threatened Grassy Box Woodlands of the lower slopes and plains (Fig 1.).

Fig 1. Map of the S2S area and priority landscapes for Bushlinks

Fig 1. Map of the S2S area and priority landscapes for Bushlinks

The increasing isolation of plant and animal populations in “island” reserves scattered through an agricultural landscape is a recognised threat to the long term viability and resilience of ecosystems under potential impact of climate change. If we can increase the viable breeding habitat through off-reserve remnant conservation, and increase the habitat for dispersal by increasing connectivity, we may be able to influence the trajectory for some of our species – the Squirrel Glider (Petaurus norfolcensis)) and threatened woodland birds in particular.

The S2S Bushlinks Project is attempting to address connectivity issues through the following approaches:

1. Cross property planning. Foster and encourage cross property planning for habitat connectivity between neighbours, community, Landcare and/or subcatchment groups resulting in more integrated on-ground works projects, and raising awareness of the benefits of connectivity for wildlife.

2. On-ground investment in connectivity. The project is partnering with farmers and land managers to support and encourage fencing and revegetation in strategic places in the landscape with the objective of increasing habitat connectivity.  S2S Bushlinks applies scientific principles to the site assessments and evaluation, which then sets the level of investment in a site.  High scoring sites receive the highest rates of rebate, but the provision of low levels of public investment in sites that may not be of high priority is important for fostering participation in revegetation of any sort to encourage the culture of caring for the land.

Site assessment and scoring for funding level uses the following criteria:

  • Connectivity and landscape value – Does the site link to or create new patches of habitat according to principles of habitat connectivity? (Fig 2)  Is there existing vegetation in 1000ha radius around the site in an optimal range of 30-60%?
  • Area : perimeter ratio – Bigger blocks of revegetation are more cost-efficient and better habitat than linear strips of revegetation, and the project scoring encourages landholder to go bigger and wider in order to qualify for a higher level of funding.
  • Habitat Values – Does the site have existing values like old paddock trees, rocky outcrops or intact native ground layer, and therefore become a more valuable site? Is it in the more fertile, productive parts of the landscape and therefore of more productivity benefit for wildlife as well?
  • Carbon value – The scoring is based on the size of the revegetation and rainfall zone. The CFI Reforestation tool is being used to value the collective potential carbon sequestration of the Bushlinks project.

The emphasis on cross-property planning flows through to the implementation of on-ground works. Landholders are encouraged to work with neighbours and the site evaluation system is used to assess site value without the property boundaries – cooperation makes the site bigger and usually increases the connectivity value, and therefore scores higher.

3. Review and adaptive management process. The site assessment is to be reviewed in July 2013 against the objectives – did it work to prioritise sites well – did we invest wisely? The scientists and experts are then able to work closely with Holbrook Landcare to adjust the project eligibility, assessment and evaluation criteria to continually improve the outcomes in subsequent funding years.

4. Monitoring framework. As part of the in-kind contribution to the project, S2S partners Dr Dave Watson, CSU Albury and Dr. Veronica Doerr, CSIRO are working towards a framework for the long-term monitoring of landscape scale connectivity for continental-scale initiatives like Great Eastern Ranges (GER).  As part of a GER Environmental Trust Project in 2013, an expert panel workshop will be convened to begin this process in 2013.

The framework will then be used to pilot a project-scale design for Bushlinks, which will allow us to measure ecological outcomes.

Bushlinks will contribute to the Slope2Summit portal of the Atlas of Living Australia, supported by the Slopes2Summit facilitator. To develop community participation in monitoring and evaluation, participants and the wider community will be encouraged to contribute wildlife sightings and other data to the atlas.

The S2S partnership applied for funds through the Australian Governments Clean Energy Futures Biodiversity Fund in 2011 and was successful in the 2011/12 funding year for a six year project. Holbrook Landcare Network is managing the S2S Bushlinks Project on behalf of the Slopes2Summit and the Great Eastern Ranges Initiative, in partnership with Murray CMA.

Contact: Kylie Durant, Bushlinks Project Officer, Holbrook Landcare Network, PO Box 121 Holbrook, NSW 2644 Australia. Tel: +61 2 6036 3121

Fig 2. Summary of the connectivity model outlined in Doerr, V.A.J., Doerr, E. D and Davies, M.J. (2010) Does Structural Connectivity Facilitate Dispersal of Native Species in Australia’s Fragmented Terrestrial Landscapes? CEE Review 08-007 (SR44). Collaboration for Environmental Evidence: www.environmentalevidence.org/SR44.html

Fig 2. Summary of the connectivity model outlined in Doerr, V.A.J., Doerr, E. D and Davies, M.J. (2010) Does Structural Connectivity Facilitate Dispersal of Native Species in Australia’s Fragmented Terrestrial Landscapes? CEE Review 08-007 (SR44). Collaboration for Environmental Evidence: http://www.environmentalevidence.org/SR44.html

Fig 3. Revegetation in the farming landscape in the Southwest Slopes of NSW

Fig 3. Revegetation in the farming landscape in the Southwest Slopes of NSW

 

 

West Hume Landcare Group – Taking stock, 24 years on

Judy Frankenberg

Key words: agricultural landscape restoration, community involvement, salinity, threatened species

The West Hume Landcare Group was formed in 1989 as a community response to land degradation in the area. Funding to employ a coordinator for three years was obtained in 1990. This enabled a high level of project activity in addition to tree planting, including a roadside vegetation survey, farm planning workshops, demonstration sites for ground water recharge and discharge management, and perennial pasture establishment. In the first 5 years of its existence, the group organised nearly 250 different events, attracted funding of over $500,000 and managed 17 different projects.

The second 5 years saw a period of consolidation – then, from late 1997, the employment of a full time project officer enabled  the development of a Land and Water Management Plan.  By early 2000 the Group had attracted a total of $1,000,000 in project funding over 11 years.

“Taking Charge of Recharge” was the largest project undertaken by the West Hume Landcare Group, commencing in 2001. It involved 80 properties, with a total of 170,009 local trees and shrubs planted on 370 ha.  Some 93 ha of remnant vegetation were fenced over the two years of the project. This project was the climax of a very busy 12 years of the Landcare Group’s life, during which 400,000 trees and shrubs were planted in a wide variety of projects across the landcare area – in addition to direct seeding and natural regeneration.  This revegetation had a variety of purposes, including recharge and discharge management, corridor linkages between remnants, vegetation connections specifically designed to strengthen the local (threatened) Squirrel Glider (Petaurus norfolcensis) population, and livestock shelter.

Many of the planting projects initially involved only small numbers of trees, with a low proportion of shrubs.  They were important in giving landholders confidence that tree planting was a credible farm management activity and in their ability to succeed in species selection and establishment.  The Landcare group provided a lot of support in species selection, and, as the demand for shrubs grew, the nurseries responded by increasing their availability.

Nearly all revegetation in West Hume has used local species, and as far as possible these were grown from locally sourced seed.  The diversity of shrub species used increased over the years as knowledge and availability of the local flora improved.

Roadside survey. Local knowledge was greatly increased following the roadside survey carried out by 38 landholder volunteers.  They surveyed 460 km of road, recording floristics, conservation value and causes of degradation.  A total of 111 native species were recorded, including 28 shrubs, but very few road sections had greater than 50% shrub cover.  Many of the shrubs. grasses and forbs recorded are considered rare in the landcare area.  Knowledge of the whereabouts of these small remnants has allowed seed collection and propagation of some of them in seed production areas on local properties and at the Wirraminna Environmental Centre at Burrumbuttock.  The need for this local source of seed has been emphasised by the observation that in the case of a few acacia species, local forms are different from those growing in neighbouring areas.

Landcare survey. Landholder views about the importance of vegetation was shown in a landcare survey carried out in 1999. A majority of the 60% of respondents considered that dieback of trees and the lack of shrubs, understorey and wildflowers was of concern and there was a clear concern expressed about the decline of native birds in the area.

When the “Taking Charge of Recharge” project was funded in 2001, the response of landholders was enthusiastic.  The group members were eager to take advantage of the high level of incentives available in this project to increase the scale of planting beyond that generally undertaken previously.  While the prime purpose of the funding was for recharge management, members were keen to establish local species in ecologically appropriate sites.  Ecological and botanical skills within the group were able to support the species choices.

This confidence in the value and feasibility of large revegetation projects has been continued in subsequent years when the Murray CMA has offered good incentives for large area plantings.

Contact:  Judy Frankenberg, +61 2 6026 5326, Email: judy@frankenberg.com.au

Fig 1. School student volunteers planting in block AA on ‘Warrangee’ in 1995.

Fig 1. School student volunteers planting in block AA on ‘Warrangee’ in 1995.

Fig 2. Resulting tree and shrub habitats created from 1995 planting on block AA, 2013.

Fig 2. Resulting tree and shrub habitats created from 1995 planting on block AA, 2013.

Fig 3. ‘Corridors of green’ project, 2013, planted in 1994, “Warrangee” .

Fig 3. ‘Corridors of green’ project, 2013, planted in 1994, “Warrangee” .

Holbrook Landcare “Rebirding the Holbrook Landscape” – assessing performance and learning in action

Chris Cumming and  Kylie Durant

Key words: tree dieback, lerps, restoring the agricultural landscape, community involvement, Holbrook Landcare Network

Holbrook producers established Holbrook Landcare Network in 1988.  It was one of the first Landcare groups in Australia, covering initially 171,000 ha of productive agricultural land in the upper reaches of the Murray Darling Basin. The organisation has directly managed grants of more than $6M across more than 85 projects to address NRM and agricultural issues including salinity and erosion control, soil and pasture management the protection of wildlife habitat.

Of the habitat projects, one of the most successful has been the “Rebirding Project”. A recognition of the importance of birds in the landscape occurred in 1994, when there was widespread concern in Holbrook over eucalypt tree dieback and the potential loss of paddock trees in the landscape. Holbrook Landcare commissioned a survey that identified 41% of the trees in the district were showing signs of dieback, and initiated (with support from our own extension staff and Greening Australia) education programs to inform landholders about the causes of dieback, including the link between cycles of lerp and other insect attack exacerbated by the loss of insectivorous birds.

In 1999 the group was successful in gaining funding for the “Rebirding the Holbrook Landscape to mitigate dieback” revegetation program through the Australian Governments Natural Heritage Trust (NHT), with the aim of drawing birds back onto farms and reducing eucalypt tree dieback.

Actions undertaken. Bird surveys were undertaken at 94 study sites in remnant vegetation on hills, flats and along creek lines. Education components succeeded in engaging the community and increased community knowledge and awareness of habitat issues in Holbrook.  The research information was used to recommend specific guidelines for the revegetation component, including ideal patch size (min 6ha), distance to remnant (1km), position in the landscape and habitat values.

The Rebirding on-ground projects (1999 – 2002) achieved 2150ha of remnant and revegetation work and put 475,000 plants back in the landscape across 118 properties – estimated at 80% of the Holbrook landholders.

Outcomes achieved. Measuring success of the program was very important to the community. A partnership with CSIRO Sustainable Ecosystems gave rise to a research project measuring bird use of plantings and remnant vegetation on local farms in 2004 to 2006.  This found that a range of bird species rapidly colonised planted areas and showed evidence of breeding activity, a positive message about the early signs of success of the Rebirding project. Tree health monitoring is ongoing by the community. Current ANU research is showing the positive benefit of the revegetation work in the landscape at the site, farm and landscape scale. The science is therefore indicating that yes, “rebirding” of the Holbrook landscape is underway, and HLN will continue to look to science to help us with the longer term outcomes for birds and tree health, and provide the feedback to us to adaptively manage our programs for the best outcomes.

The lessons and recommendations that come from the research are being applied directly to inform the design of subsequent programs such as the current major biodiversity project being managed by Holbrook Landcare – the “Slopes to Summit Bushlinks Project”.

Contacts: Chris Cumming (Executive Officer) and Kylie Durant,  Holbrook Landcare Network, PO Box 181 Holbrook NSW, Australia.  2644 Tel: +61 2 6036 3121, Email: kyliedurant@holbrooklandcare.org.au.

Paddock tree health field day, Holbrook, 2011.

Paddock tree health field day, Holbrook, 2011.

Before planting habitat blocks at Woomargama station, Holbrook.

Before planting habitat blocks at Woomargama station, Holbrook.

Stands of trees and shrubs established at Woomargama station, Holbrook.

Stands of trees and shrubs established at Woomargama station, Holbrook.

Wimmera CMA Catchment Tender model – evaluation after 5 years demonstrates significant improvements in efficiency and value for money

Key words: ecological sustainability, incentives, market-based instruments, salinity

Robert Moir

Wimmera Catchment Management Authority (WCMA) helps manage natural resources across 2800 square kilometres of land in western Victoria. In 2005, the WCMA teamed up with environmental economic researchers from CSIRO to design and implement an innovative market-driven model to address salinity problems in key parts of the catchment. This has resulted in a $4.6 million investment in environmental projects on farms in the past six years, in turn, delivering a dramatic increase in on-ground works such as fencing, weed and pest animal control, revegetation and protecting waterways compared with traditional incentive programs of the previous decade.

Through this initial Catchment Tender model, the CMA invited farmers to submit tender proposals and be paid for establishing and maintaining vegetation on their farms. The model, an alternative to grants, targeted specific farms where revegetation work would help reduce salinity problems across the catchment. The computer-based model assessed the costs and benefits of the tenders and selected the ones which offered the best value for money of terms of salinity benefits per dollar of public funds invested.

Participation in this first round of Catchment Tender far exceeded expectations, with more than $730,000 invested into salinity management across 762 hectares of land in just 10 months. This is the equivalent of at least the previous five to six years of revegetation achievements through the CMA’s previous grants scheme. There have been efficiency gains of up to 160% in delivery, and 69% of the project’s total budget has been paid to landholders; this includes development costs dating back to 2002. Based on an evaluation done with the CSIRO we found that by comparison, traditional incentive projects would on average require a budget 60% higher than Catchment Tender to generate the same outcome. Because of this result, the CMA extended this market-based approach to other programs including biodiversity conservation and protecting wetlands and riparian corridors along waterways, and since the first round in 2005, Wimmera CMA has helped invest $4.6 million across the region.

The CMA has completed 12 tender programs including River Tender, Habitat Tender and Buloke Tender. These programs help protect our region’s waterways, wetlands, plants and animals. Six years down the track, the CMA and the CSIRO are now evaluating these market-driven programs as well as other natural resource management investment programs such as grants and Landcare group support.

Contact: Robert Moir, Program Manager- Catchment Operations, Wimmera Catchment Management Authority, PO Box 479, Horsham, 3401, Tel: +61 (03) 5382 1544 or email wca@wcma.vic.gov.au.

Experimental supplementation of nest boxes to Eucalyptus plantations established on farmland

Key words: Biodiversity, restoration, monitoring, timber plantations, Liverpool Plains

Brad Law

Eucalypt plantings clearly lack certain resources and habitat components that are important for many fauna, for example tree hollows.  Our team at the Forest Science Centre has been documenting the capacity of young (6-8 year old) eucalypt plantations to restore habitat for fauna within a highly cleared, intensive agricultural landscape on the Liverpool Plains of NSW.  Most of this region occurs on flat, fertile, basalt-derived, black soils that have been extensively cleared and now support cropping for sorghum and sunflowers as the dominant land use.  As part of this study we have established a long-term, rigorous field experiment to test the effect of supplementing plantings with artificial habitat in the form of nest boxes and ground cover, using a before and after comparison.  We predicted that the addition of nest boxes/ground cover would increase the relative abundance of targeted fauna species within the supplemented plantations in relation to paired plantation controls.  Nest boxes and ground cover boards were inspected twice within 18 months of installation to determine their suitability for different species and to discover the extent to which they are used by fauna.

Sugar glider occupying a multi-chambered nest box in a plantation on the Liverpool Plains, NSW (Photo: Matthew Stanton)

These initial inspections found that the addition of nest boxes provided otherwise missing tree hollow resources for four species of bats, three species of marsupials, two species of parrot, one hollow-nesting raptor, two species of reptiles and two species of tree frogs. Invertebrates also made extensive use of all boxes (three designs) provided. One kind of nest box used in this trial was used by the Common Starling, a pest species.  Nest box uptake by some species, such as the Sugar Glider, was limited by proximity to remnant populations.  Several mammal species normally considered terrestrial, such as the Common Dunnart, were recorded using the nest boxes.  Cover boards greatly increased the counts of reptiles, especially skinks, in plantings, indicating that a lack of cover seriously restricts the use of plantings by reptiles.  Both forms of habitat supplementation (nest boxes and ground cover) will require further inspections and surveys in coming years as the plantings develop to fully test the hypotheses of the experiment.

Six year old Eucalyptus plantation on the Liverpool Plains, NSW (Photo: Brad Law)

The full report (by Rod Kavanagh, Brad Law, Frank Lemckert, Matthew Stanton, Mark Chidel and Traecey Brassil) can be downloaded from http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0003/326847/Kavanagh_Eucalypt-Plantations_Final-Report_vlow_res.pdf

Contact: Brad Law: Forest Science Centre, Industry and Investment NSW, PO Box 100 Beecroft NSW 2119. Email: bradl@sf.nsw.gov.au

Wildlife in commercial Eucalyptus plantations in NSW – a long-term study

Key words: timber plantation, biodiversity, fauna, monitoring, remnant vegetation, threatened species

Law B., Chidel M. and Turner G.

Little is known about the biodiversity that occurs in commercial scale eucalypt plantations, how this changes with time or what effect plantations might have on the wildlife occurring in remnant vegetation previously fragmented by farmland. This project, which is being undertaken by Brad Law, Mark Chidel and Graham Turner from the Forest Science Centre, aims to track changes in wildlife in commercial eucalypt plantations on the north coast of NSW. These plantations are grown for saw-logs and they comprise tree species that are locally indigenous. Fauna surveys began at the pre-plantation stage in 1997, when sites were cleared farmland with scattered remnant vegetation. Since then re-surveys have been undertaken when plantations were 1 and 5 years old. The last re-survey was undertaken in spring 2009, coinciding with plantation trees being 11 years old. Fauna surveys have focused on diurnal birds, bats, arboreal mammals and ground mammals. Survey sites are located in different classes of remnant vegetation embedded within plantations including: single remnant trees, small tree patches, larger remnants and riparian strips. Additional sites are also located within the plantations remote from remnant vegetation and native forest adjacent to the plantation.

A mosaic of remnant vegetation and 11 year old Eucalyptus plantation in northern NSW (Photo: Brad Law)

The data are yet to be statistically analysed, but the observations during our field-work suggest that biodiversity levels are increasing from that present prior to plantation establishment. Some interesting observations include an apparent increase in numbers of Squirrel Gliders and Sugar Gliders, a decline in Noisy Miners across most plantation areas, which appears to have coincided with an increase in small insectivorous birds, the use of plantation trees as a nectar resource by three threatened species (Squirrel Glider, Brush-tailed Phascogale and Grey-headed Flying Fox), but little recovery of small mammal numbers, possibly due to the effects of continued cattle grazing, which keeps ground cover to a minimum. Future surveys will continue to track the changing status of wildlife in these plantations to inform issues relating to the ecological sustainability of plantations.

Contact: Brad Law: Forest Science Centre, Industry and Investment NSW, PO Box 100 Beecroft NSW 2119. Email: bradl@sf.nsw.gov.au

Squirrel glider feeding at flowers in a 5 year old Blackbutt Eucalyptus pilularis plantation, northern NSW (Photo: Alison Towerton)