Category Archives: Weed issues & solutions

Integrating conservation management and sheep grazing at Barrabool, NSW

Martin Driver

Key words: semi-arid, grazing management, conservation management, rehabilitation, ecological restoration

Introduction. Barrabool is a 5000 ha dryland all-Merino sheep property between Conargo and Carrathool in the Western Riverina, NSW. Native pastures are the mainstay of Barrabool, as they are of other grazing properties in the arid and semi-arid rangelands of New South Wales that generally lie to the west of the 500 mm average rainfall limit.

Indigenous ecosystems at Barrabool occur as native grassland, mixed acacia and callitris woodlands and shrublands. The main grass species in the grasslands are Curly Windmill (Enteropogon sp.), White Top (Rytidosperma sp.), Box Grass (Paspalidium sp.), Speargrass (Austrostipa spp.), and Windmill Grass (Chloris sp.). Broad-leaved species include Thorny Saltbush (Rhagodia sp.), Cotton Bush (Maireana sp.) and a diverse annual forb layer in Spring..

The majority of the property has belonged to the Driver family for over 100 years. Like many of the surrounding stations a gradual but noticeable increase in exotic species occurred during the mid-to-late 20th Century, and a decline in native species. This transition has occurred because of species being transferred by livestock movements and because sheep graze not only on grass, but also saltbush shrubs and sub-shrubs as well as seedlings of native trees such as Boree (Acacia pendula) and White Cypress Pine (Callitris glaucophylla). It is well known, for example, that the preferential and continuous grazing of Boree by sheep can turn a Boree woodland into a grassland .within a manager’s lifetime unless rest and regeneration are allowed.

In recent decades – because of the Driver family’s interest in conservation and our exposure to advances in grazing management, paddock subdivision and stock water relocation – we have developed in recent decades a managed grazing system based on feed availability, regeneration capability and seasonal response to rainfall. It was our hope that this system could improve the condition of native vegetation while also improving feed availability.

Figure 1. Boree (Acacia pendula) and Thorny Saltbush (Rhagodia spinescens) in grazed paddocks at the Driver’s 5000 ha sheep property, Barabool, in the western Riverina. (Photo M. Driver).

Figure 1. Boree (Acacia pendula) and Thorny Saltbush (Rhagodia spinescens) in grazed paddocks at the Driver’s 5000 ha sheep property, Barabool, in the western Riverina. (Photo M. Driver).

Works undertaken. Over the last 35 years we have progressively fenced the property so that it is subdivided by soil type and grazing sensitivity, with watering systems reticulated through poly pipe to all those paddocks. This enables us to control grazing to take advantage of where the best feed is and move stock from areas that we are trying to regenerate at any one time; and it gives us a great deal more control than we would have had previously.

Using our grazing system, we can exclude grazing from areas that are responding with regeneration on, say Boree country, for periods of time until Boree are less susceptible to grazing; at which time we bring stock back in. We take a similar approach to the saltbush and grasses, moving sheep in when grazing is suitable and moving them off a paddock to allow the necessary rest periods for regeneration. In this way we operate a type of adaptive grazing management. We also have areas of complete domestic grazing exclusion of very diverse and sensitive vegetation which are essentially now conservation areas.

Figure 2. Mixed White Cypress Pine Woodland grazing exclosure on Barrabool with regeneration of Pine, Needlewood, Sandalwood, Rosewood, Butterbush, Native Jasmine, mixed saltbushes and shrubs. (Photo M. Driver)

Figure 2. Mixed White Cypress Pine Woodland grazing exclosure on Barrabool with regeneration of Pine, Needlewood, Sandalwood, Rosewood, Butterbush, Native Jasmine, mixed saltbushes and shrubs. (Photo M. Driver)

Results. The native vegetation at Barrabool has noticeably improved in quality terms of biodiversity conservation and production outcomes over the last 35 years, although droughts have occurred, and in fact been more frequent during this time.

In terms of conservation goals Boree regeneration and Thorny Saltbush understory restoration has been both the most extensive and effective strategy. Areas of mixed White Cypress Pine woodland have proven to be the most species diverse but also offer the greatest challenges in exotic weed invasion and management. The Pines themselves are also the most reluctant to regenerate and suffer many threats in reaching maturity while many of the secondary tree species are both more opportunistic and show greater resilience to drought and other environmental pressures. The increase in perenniality of grass and shrub components of the property have been significant, with subsequent increase in autumn feed and reduced dependence on external feed supplies.

In terms of production outcomes, after the millennium drought the property experienced three seasons in a row in which there was much less rainfall than the long term average rainfall. At the beginning of that period we had the equivalent of more than the annual rainfall in one night’s fall and then went for 12 months from shearing to shearing with no rain recorded at all. Yet the livestock and the country, however, did very well compared to other properties in the district, which we consider was due to the stronger native vegetation and its ability of the native vegetation to withstand long periods without rain.

Lessons learned and future directions. While many other sheep properties in the wider area are more intent on set stockingin their grazing practices, the results at Barrabool have demonstrated to many people who have visited the property what is possible. I am sure we are also are having some effect on the management systems of other properties in the district especially in the area of conservation areas excluded from grazing.

What we plan for the future is to explore funding options to fence out or split ephemeral creeks and wetlands and encourage Inland River Red Gum and Nitre Goosefoot regeneration.Our long term goal is to maintain the full range of management zones (including restoration zones earmarked for conservation, rehabilitation zones in which we seek to improve and maintain biodiversity values in a grazing context, and fully converted zones around infrastructure where we reduce impacts on the other zones.

Contact:   Martin Driver Barrabool, Conargo, NSW 2710 Email: barrabool@bigpond.com

Subtropical rainforest restoration at the Rous Water Rainforest Reserve, Rocky Creek Dam, 1983 – 2016

Key words: Lowland subtropical rainforest, ecosystem reconstruction, drinking water catchment, continual improvement process.

Introduction. Rous Water is actively engaged in ecosystem reconstruction within the drinking water catchment areas it manages on behalf of the community. The aim of these activities is to improve the functioning of essential natural processes that sustain water quality. The methodology used for rainforest restoration by Rous Water has evolved over time through an ‘adaptive management’ process at Rocky Creek Dam. This adaptive management approach has demonstrated that effective large scale sub-tropical regeneration at Rocky Creek Dam is achieved through complete removal of competing plants. The technique has become known as the Woodford Method and is now being applied at other Rous Water restoration sites.

The Rous Water Rainforest Reserve at Rocky Creek Dam is set in the northern headwaters of the Richmond River catchment, on the southern rim of the Tweed shield volcano. Basalt flows from the volcano have produced nutrient rich Red Ferrosol that supported diverse sub-tropical rainforest ecosystems across the region, until the rainforest was largely cleared for agriculture in the late 19th century. The Rocky Creek Dam site is adjacent to the Big Scrub Flora Reserve, the largest remaining remnant subtropical rainforest in the region. This reserve acts as a reference site for the restoration project (Fig 1).

Figure 1. Detail of the regeneration areas at Rocky Creek Dam, showing the areas treated and the year of the initial works

Figure 1. Detail of the regeneration areas at Rocky Creek Dam, showing the areas treated and the year of the initial works

Clearing of land in the vicinity of Rocky Creek Dam by early settlers commenced in the 1890s, with the cleared lands used for the establishment of dairy farms and a sawmill. In 1949, following acquisition of the site by Rous County Council (now Rous Water) for the construction of a water supply dam, this former farmland had reverted to weedy regrowth characterised by a mosaic of native/exotic grass, Lantana (Lantana camara) and Camphor Laurel (Cinnamomum camphora) which supressed any expansion or recovery of scattered rainforest remnants. Transformation of the site commenced in 1983 when Rous Water became actively engaged in ecosystem recovery by systematically removing weeds that suppressed rainforest regeneration, a practice that continues today.

Rainforest restoration methods. The practices and management tools used in rainforest restoration at the site have been previously described by Woodford (2000) and Sanger et al. (2008). The work method typically involves the systematic poisoning and slashing of weeds to promote recruitment of rainforest plants from the soil seed bank and then to facilitate the growth of suppressed rainforest plants, providing a structural framework for further seed dispersal by wind and, particularly, flying frugivores and thus further colonisation by later phase rainforest trees.

Since 1983, an area of approximately 70 ha has been progressively treated in 1-2 ha blocks using this methodology (refer Fig 1), with progressively diminishing amounts of follow-up treatment needing to be conducted in the treated areas over subsequent years to secure successional progression of the rainforest species.

Use of this method means that, due to recruitment from the seed bank and the use of stags (from dead camphor laurel) as perches for seed dispersing birds, very limited planting has been required on the site. This has preserved the genetic integrity of the Big Scrub in this location.

Results. A total of approximately 70 hectares of weed dominated regrowth has been treated at the Rous Water Rainforest Reserve since commencement in 1983 (Figure 1). This is approximately 35 ha since the report previously published in 2000 and represents approximately 30 % of the Rous Water property at Rocky Creek Dam.

This progressive treatment of compartments of weedy regrowth at Rocky Creek Dam has continued to lead to rapid canopy closure by shorter lived pioneer and early secondary tree species, with a gradual progression to higher proportions of later secondary and primary species with increasing time since treatment. All tree species that are listed as occurring in the reference site are not only now present in the restoration area, but informal observations suggest that most, if not all, are increasing in abundance over time (Figs 2-6)

Figure 2. Treated regrowth at the Rous Water Rainforest Reserve, Rocky Creek Dam After 1 year (foreground)

Figure 2. Typical regeneration of rainforest species 1 year after Lantana removal at the Rous Water Rainforest Reserve, Rocky Creek Dam (foreground).

Figure 3. Same photopoint after 6 years

Figure 3. Typical recovery after 6 years

Figure 4. Same photopoint after 12 years

Figure 4. Typical recovery after 12 years

Figure 5. Same scenario after 20 years

Figure 5. typical recovery after 20 years

Figure 6. After 30 years

Figure 6. Typical recovery after 30 years

The structure of the older treated regrowth areas sites appears to be converging on rainforest conditions, as noted by Kanowski & Catterall (2007). Thackway & Specht (2015) depict how 25 ha of systematically treated compartments that were covered almost entirely with lantana are progressing back towards the original Lowland Subtropical Rainforest’s composition, structure and ecological function (Fig 7). Overall the vegetation status in this area was assessed at between 85% and 90% of its pre-clearing status.

This process is, at its oldest 33 years old and in some locations much younger. So it is clear that the development of the subtropical vegetation still has many decades, possibly centuries, to go, before it approaches the composition, structural and habitat characteristics of a primary forest. Notwithstanding the large areas of natural regrowth that are yet to be worked, it is evident that a large proportion of the assisted regeneration areas progressively worked by Rous over the past 33 years now requires only a low level of ongoing maintenance. This shows that these sites are maturing over time and have largely reached a self-organising state, and in the fullness of time will achieve a high degree of similarity to the reference state.

Fig 7, Thackway fig rocky creek dam1

Figure 7. Assessment of change in indicators of vegetation condition in a 25 ha area. This depicts the degree of recoveery of Lowland Subtropical Rainforest found at Rocky Creek Dam, Big Scrub, NSW against a pre-clearing reference. (Graph reproduced with permission. The method used to generate the graph is described in Thackway, R. and Specht, A., (2015). Synthesising the effects of land use on natural and managed landscapes. Science of the Total Environment. 526:136–152 doi:10.1016/j.scitotenv.2015.04.070. ) Condition indices for transition Phase 4 were derived from prior reports including Sanger et al. 2008 and Woodford 2000. Metadata can be viewed at http://portal.tern.org.au/big-scrub-rocky-queensland-brisbane/16908 .

Lessons learned. Using this method of harnessing the natural resilience processes of the rainforest, we have been able to progress the recovery of an important water catchment area, restoring very high biodiversity conservation values in a landscape where rainforest was, and remains, in serious decline., The ability of the high resilience sites at Rocky Creek Dam to respond to the Woodford Method is clearly demonstrated, but there is ample evidence that application of this and similar resilience-based rainforest restoration methods can harnessed resilience at other sites in the Big Scrub that are at greater distances from remnants.

Figure 8. Distribution of management intensity classes across the Rous Water Rainforest Reserve at Rocky Creek Dam.

Figure 8. Distribution of management intensity classes across the Rous Water Rainforest Reserve at Rocky Creek Dam. (Legend for this map is in Appendix 1)

Current work and future directions. Work continues at the site and management is supportive of-site evaluation to assess the extent to which the treated areas are undergoing successional development using a range of available assessment tools.

To assist future planning, and in order to address the issue of how to best estimate and plan for restoration works and associated costs, Rous Water has adapted the methodology developed on the Tweed-Byron Bush Futures Project, where each restoration site/area was assigned a Management Intensity Class (MIC) based on a generalised assessment of site condition, weed composition and cover and other management requirements. (Fig 8) The MIC describes the frequency of restoration work required to restore the site to a minimal maintenance level and how many years this would take to achieve. The MIC aims to describe the extent of management intervention necessary to restore the site to a minimal maintenance level. For this analysis this equates to the establishment of a self sustaining sub-tropical rainforest buffer zone. Each management intensity class is associated with a particular restoration trajectory/cost per hectare, based on visitation frequency by a standard 3 person team and expressed in terms of number of visits required to control / manage weeds. Appendix 1 below shows details of the MIC classification, showing for each class, relevant site criteria, and the estimated level of bush regeneration resources required to bring each class to a low maintenance level.

Contact: Anthony Acret, Catchment Assets Manager,  Rous Water. Tel: +61 (0) 2 6623 3800, Email: anthony.acret@rouswater.nsw.gov.au

Appendix 1. Legend for Management intensity classes used in Fig 8. (From Tweed-Byron Bush Futures)

Appendix 1. Legend for Management intensity classes used in Fig 8.

Establishment of an assisted natural regeneration model for Big Scrub sub-tropical rainforest: The Woodford Method

The results of long-term restoration at Rocky Creek Dam, have informed the development of an assisted natural regeneration model for sub-tropical rainforest known as The Woodford Method (named after the pioneering restoration work of Ralph Woodford). This method is now commonly applied across the Big Scrub region, particularly on high resilience sites and is more fully explained in Woodford (2000).

Figure 1. Remove Lantana thickets.

Figure 1. Remove Lantana thickets.

1. Winter (July-August) – refer Figure 1. In a typical area of secondary regrowth dominated by weeds such as Camphor Laurel (Cinnamomum camphora), Privet (Ligustrum sinense) and Lantana (Lantana camara), Lantana is the weed that should be killed first. Winter is the best time to do this as it is dry and it won’t reshoot when on the ground. In extensive areas, this can be done effectively by flattening thickets of Lantana with a tractor, then slashing it repeatedly to create a deep mulch, and pulling the Lantana stumps out to disturb the soil. Removing the Lantana thickets also allows access to tree weeds.

Figure 2. Kill Privet and Camphor Laurel.

Figure 2. Kill Privet and Camphor Laurel.

2. Spring (September-October) – refer Figure 2. Tree weeds such as Camphor and Privet have their biggest growth spurt, so this is a good time to give them a shot of herbicide to kill them. (Leaving the Camphor in place rather than cutting them down means that they act as ‘perch trees’ for birds and bats to land on and spread seeds through their droppings). As the Lantana, Camphor and Privet die, their leaves and branches fall to the ground and form a rich mulch on the forest floor. Light is also able to reach the forest floor, where previously it had only reached the canopy.

Spring storms come and wet the mulch, and fungal mycelium (the feeding filaments of fungi) move through the mulch and break it down, fertilising and leaving bare patches of soil where the mulch layer has totally receded.

Figure 3. Remove annual weeds.

Figure 3. Remove annual weeds.

3. Late spring / early summer (November-January) – refer Figure 3. Where you have bare soil, and there is moisture, light and an appropriate temperature, you will get seed germination. The first things to come up are annual weeds such as ‘Farmers Friends’ or ‘Cobblers Pegs’ (Bidens pilosa); ‘Blue Billy Goat Weed’ (Ageratum houstonianum); and ‘Crofton’ or ‘Mistweed’ (Ageratina spp). Annual weeds are always first to appear. They will germinate on the smell of a storm and a slight increase in temperature. Camphor and privet seedlings often come up at the same time.

When the weeds grow, they form a canopy just like the forest but at a height of one metre. In this way, weeds stop light from reaching the forest floor, inhibiting the growth of rainforest seedlings.

Therefore, it is important to remove these annual weeds and not let them go to seed. Depending on time available they are either pulled or sprayed. The experience at this site has been that the seedbank is strong enough to lose some rainforest seedlings in this initial spraying. If using herbicide, two sprays during this season generally removes all the weeds and their seeds.

Figure 4. Weed around rainforest seedlings.

Figure 4. Weed around rainforest seedlings.

4. Late summer / early autumn (February-March) – refer Figure 4.The seeds of rainforest species tend to germinate after the highest summer temperatures (sometimes up to 38 and 40 degrees) have passed. By late February and early March, daytime temperatures don’t generally go over 30 degrees, but the soil temperature and moisture is at its maximum. These conditions can produce a massive germination of rainforest seeds and those seedlings grow up very rapidly. Hand weeding is usually needed around these rainforest ‘pioneers’.

Figure 5. Enjoy the growing rainforest.

Figure 5. Enjoy the growing rainforest.

5. Early winter (May-June) – refer Figure 5. On a good site, with the best seasonal conditions, many of these rainforest seedlings will have grown to saplings above head height and can create a closed canopy within the same year. This means that less light reaches the forest floor, which reduces the amount of weed regrowth in this area – but there is still enough light for later successional rainforest seedlings to germinate, building the rainforest diversity over time.

Note: The process may be slightly different depending on the type of ‘before restoration’ landscape. Refer to Woodford (2000) for more information.

Contact: Anthony Acret,  Catchment Assets Manager, Rous Water, NSW Australia. Tel+62 2 6623 3800; Email: anthony.acret@rouswater.nsw.gov.au

Learning from the Coreen TSRS – and scaling up biodiversity recovery works at hundreds of sites in the Riverina, NSW.

Peter O’Shannassy and Ian Davidson

Key words: Travelling Stock Routes and reserves, grazing management, rehabilitation, direct seeding, Biodiversity Fund.

Introduction. The travelling Stock Routes and Reserves (TSRs) in NSW comprise a network of publically owned blocks and linear routes that were set aside between 100-150 years ago in New South Wales (NSW) to allow landholders to move their livestock from their grazing properties to markets. They occur in prime agricultural land and remain under management by the state of New South Wales’s system of Local Land Services organisations (LLSs).

Since trucking of cattle is now the norm, rather than droving, the use of TSRs has gradually changed to more occasional grazing. Considering the concurrent gradual decline in biodiversity of many private properties in the same period this means that the remnant grassy woodland patches and corridors represent the most important habitats in the Riverina region and contain dozens of Threatened species and five Endangered Ecological Communities variously listed under the NSW Threatened Species Conservation Act 1995 (TSC Act 1995) and the Commonwealth EPBC Act 1999. A general recognition of the high biodiversity value of the TSRs (and need to counter degradation on many of them) has resulted in a shift in local policy and practice towards improving the condition of biodiversity in the reserves.

Fig. 1

Fig. 1. Coreen Round Swamp TSR 2005.

Fig. 2

Fig. 2.  Coreen Round Swamp TSR at the same photopoint in 2015. (Note the increase in Bullloak recruitment from improved grazing management.

Works undertaken at Coreen Round Swamp and Oil Tree Reserve

Managed grazing has been applied to a number of Travelling Stock Reserves in the Riverina over a 10 year period – particularly two reserves: Coreen Round Swamp and Oil Tree reserve in the Coreen area. In 1998, condition of Coreen Round Swamp was ranked high conservation quality and Oil Tree TSR medium-high. In general, both TSRs contained tree species at woodland densities, but there was a low density of regenerating palatable trees (e.g. Bulloak and White Cypress Pine), with most species where present recorded as having sparse natural regeneration. The sites contained few regenerating shrubs (again rating sparse or absent) and exotic annual grasses were common in parts, with native grass swards patchy. Weed forbs were common

Restoration works commenced at Coreen Round Swamp and Oil Tree Reserve in 2004 and focused on:

  • Manipulating the timing of grazing with selected sets of livestock at specific times to disrupt the life cycle of, particularly, annual exotic grasses to reduce these undesirable species and to prepare the way for native perennial grasses.
  • Weed control – which involved multiple visits to the site throughout the year to control the various species as they emerged and prior to seed set. Spraying of herbaceous species with knockdown herbicide continued until the balance tipped and began to move towards a stronger native composition. Woody weeds such as Olive and Pepper trees were removed by hand cutting and painting with systemic herbicides.
  • Reduction of grazing impacts: Livestock were camped in the TSR’s holding yards rather than under the trees at night. This was carried out to reduce physical damage to shrubs, trees and the ground layer and reduce fertility inputs to the soils under the trees; fertility levels that are known to favour weed species invasion of such areas.

Results. Monitoring using standard proformas and photopoints showed dramatic changes in both reserves; with sites previously devoid of recruitment now developing a layer of tree and shrub saplings including Bulloak and White Cypress Pine. Where once 20-30% of the Coreen Round Swamp TSR was highly degraded, being dominated by herbaceous and grass weeds, this degradation class has now reduced to less than 10%; with the remaining 90% being of high quality. Similarly Oil Tree TSR had around 30-40% in a similarly degraded condition, which has now been reduced to 10-15% of the area; with 80% being in moderate-high condition and moving towards high as the shrub layer improves. (See Figures 1-4).

Fig 3.

Fig. 3. Oil Tree TSR in 2005 where a mix of native grass (spear grasses) and exotic annual grasses (Wild Oats, Bromus and Rye Grass) are visible.

Figure 4


Fig 4.  Same photopoint at Oil Tree TSR in 2015 showing a sward now dominated by native grass (spear grasses) and Curly Windmill Grass (Chloris truncata).

Expansion of the program to hundreds of TSRs in the Riverina

Building on the success of the work at the Coreen Reserves, a five year program is well underway, funded by the Australian Government’s Biodiversity Fund in 2012. In the first for four years, 251 sites have been assessed and interventions have taken place at 102 of these sites; with a further 18 sites to be worked during the remaining funded period.

Works to date include grazing management, weed and pest species management and 960 ha of direct seeding on 70 sites. The sites are being monitored using 250 permanent photopoints located to track key vegetation structural changes, as well some transect counts of regeneration and seedling success (recruitment). Approximately 108 assessments, using the original proformas plus plot counts, are being conducted on a subset of key sites including untreated sites. Initial results of the grazing management and direct seeding are encouraging. Very successful seedling germination has occurred in the direct seeded lines on most of the seeded sites (although germination on some of the drier Boree sites took longer). Some sites have had additional seeding done in subsequent years to provide a mix of age classes. The seedlings have now developed to a range of heights, with some older seedlings up to 2 m high, while some seed continues to germinate. Some of the more mature plants have seeded in the last 12 months and the expectation is that a soil seed bank will now be starting to form.

As aggressive exclusion of birds from woodland and forest habitat by abundant Noisy Miners is listed as a Key Threatening Process (KTP) in NSW and the Commonwealth – culling of Noisy Miner (Manorina melanocephala) is being undertaken to benefit woodland bird populations. This is being done at a scale not attempted before. Baseline bird surveys have been conducted on 80 sites established over 70 reserves including on sites with and without Noisy Minor culling; and sites with shrubs and without shrubs within a range of vegetation types. The seasonal benchmark surveys have been undertaken on 8 occasions but because only one post-culling survey (spring) has been undertaken to date, it is premature to identify whether changes in bird populations have occurred yet. The surveys will continue till Autumn 2017.

Lessons learned. The results of works at the Coreen reserves are clearly a direct response to the manipulation of the timing and intensity of grazing pressure to reduce weed and allow rest for recovering native species. Achieving the desired grazing management required a paradigm shift for managers and clients. The close management of grazing, direct seeding and burning also relies on a high level of understanding and commitment by the TSR manager.

Acknowledgements. We thank Rick Webster for his seminal rapid assessments of TSRs in the late 1990s throughout southern NSW. Norman Wettenhall a visionary philanthropist and a friend of TSRs funded much of the early assessment work. The more recent funding provided by the Australian Government’s Biodiversity Fund. A number of LLS staff / Biosecurity officers are involved in the works, including Peter O’Shannassy, Michael Mullins, Stuart Watson and Roger Harris. Ian Davidson, Regeneration Solutions P/L is undertaking the vegetation assessments, Chris Tzaros, Birds, Bush and Beyond, is undertaking the bird surveys and Phil Humphries provided the mapping

Contact: Peter O’Shannassy, Murray Local Land Services (74 Short St Corowa NSW 2646, 0427010891 peter.o’shannassy@lls.nsw.gov.au) and Ian Davidson Regeneration Solutions P/L (15 Weir Street Wangaratta, 0429 662 759, ian@regenerationsolutions.com.au).

Recovering biodiversity at Trust for Nature’s Neds Corner Station, Victoria

Doug Robinson, Deanna Marshall, Peter Barnes and Colleen Barnes

Key words. Private conservation area, natural regeneration, ecological restoration, rabbit control.

Introduction. Neds Corner Station is Victoria’s largest private conservation property. This 30,000 hectare ex-sheep and cattle station was purchased for nature conservation by Trust for Nature (Victoria) in 2002.

The property occupies the driest area of the state with an average annual rainfall of only 250 mm. As such, it has strong ecological links to the arid regions of Australia and Australia’s rangelands. Neds Corner sits strategically at the hub of an extensive network of public and private conservation lands bordering or close to the Murray River in Victoria, New South Wales and South Australia. The reserve is bordered on three sides by the Murray Sunset National Park and borders frontages along the Murray River and associated anabranches for more than thirty kilometres, where the River Red Gum (Eucalyptus camaldulensis) dominated riparian zone connects with Chenopod Shrublands, Semi-arid Chenopod Woodlands and Chenopod Mallee Woodlands. Trust for Nature’s restoration efforts are targeted at restoring woodland connectivity across the property to improve habitat extent and condition for woodland and mallee plants and animals, including the nationally threatened Regent Parrot (Polytelis anthopeplus). A biodiversity survey in 2011 found 884 native species at Neds Corner Station, including 6 threatened birds and animals, 77 threatened plants, and 21 species new to science. Trust for Nature continues to find new records for the property.

Fig 1 Neds 2003

Fig. 1. Highly degraded area (near watering points) in 2003 just after Trust purchased the property.

 

Fig 2 Neds 2011

Fig. 2. Same photopoint in 2014 showing extensive natural regeneration of Low Chenopod Shrubland after removal of livestock and extensive treatment of rabbits.

 

Planning for recovery. In 2002, when Trust for Nature first took on the property, the land was severely degraded from continuous over grazing by stock, rabbits and native herbivores; weed infestations; historic clearing of extensive areas of woodland for firewood and forage; and lack of flooding. Native vegetation was sparse over much of the property, soil erosion was extensive and the floodplain and semi-arid woodlands were all showing signs of extreme stress.

In the early years of ownership, management focussed on addressing the most obvious of these threats, with a focus on rabbit control and weed control. In 2010, with funding support from The Nature Conservancy, Trust for Nature prepared a Conservation Action Plan for the reserve, using the Open Standards for Conservation process, and a subsequent management plan. These planning documents identified the key biodiversity values on the reserve, the major threats to these values and the strategies to reduce threats and improve condition to achieve agreed ecological goals.Fig 6 Neds

Fig. 3. Dune Wattle (Acacia ligulata) natural regeneration after cropping was discontinued.

Fig 7 Neds

 Fig 4. Hop Bush (Dodonaea viscosa) natural regeneration after cropping ceased.

Works undertaken. Trust for Nature’s first action was to remove the livestock to allow the regeneration and growth of native vegetation. Stock fencing was decommissioned to enable free movement of native fauna, and new exclosure fencing to protect sites of cultural and ecological significance were also constructed. Major efforts were made to reduce rabbit numbers through the use of warren ripping, fumigation and 1080 baiting across the property. To date, over 20,000 warrens have been treated. Direct seeding and tubestock planting in the Semi-arid Woodland areas of the property have been continuous, with the cessation of a cropping licence, over 500 ha direct seeded in one year as part of an Australian Government funded project. In partnership with the Mallee Catchment Management Authority, environmental water allocations have been used to inundate areas of Neds Corner, providing a vital lifeline to many of the plants and animals that inhabit the riverine billabongs and floodplain forests. Artificial water points and superfluous tracks have been closed. Targeted fox and other feral animal programs are continuous.

Fig 3 Neds 2003

Fig 5. Highly degraded ‘Pine paddock’ in 2003 just after the Trust purchased the property.

Fig 4 Neds 2011

Fig 6. Pine paddock from same photopoint in n2014 after exclosure fencing, rabbit control and extensive direct seeding of trees and shrubs in 2007 (and again in 2010). The grasses all naturally regenerated.

Results. In the 14 years since domestic stock removal and the ongoing control of rabbits and weeds, there has been a dramatic increase in the cover of native vegetation, notably from natural regeneration (Figs 1-4) but also from extensive supplementary planting and direct seeding (Figs 5-8). In 2011, wide spread natural germination of Murray Pines occurred across the woodland sections of the property and Sandhill Wattle (Acacia ligulata) seedlings were observed on one rise where no parent plant was known to occur, indicating a viable seed bank may exist. The vulnerable Darling Lilies (Crinum flaccidum) continue to extend their range, given favourable weather conditions and the continuous control of herbaceous threats to the extent required to ensure adequate recruitment of these key flora species. Bird surveys undertaken for one of the targeted projects within Neds Corner over the past 10 years show an encouraging increase in reporting rates of Brown Treecreeper (Climacteris picumnus victoriae) (>x2 increase), Chestnut-crowned Babbler (Pomatostomus ruficeps) (>x2% increase) and Red-capped Robin (Petroica goodenovii) (>x20 increase).

Fig 5 neds

Fig.7. Revegetation plantings in 2008

Fig 6 NEds 2014

Fig 8. Same revegetation planing line in 2013.

Current and future directions. Trust for Nature are due to revise their CAP and have identified the need to undertake recovery actions at a greater scale. They are currently investigating the feasibility of re-introducing some fauna species back into Neds Corner Station that haven’t been found in the region for decades, provided there is sufficient habitat to sustain them.

Acknowledgements. As a not-for-profit organisation, Trust for Nature (Victoria) relies on the generous support of many individuals, organisations and government entities. The main project partners to date include The Nature Conservancy, RE Ross Trust, Yulgilbar Foundation, Australian Government, Mallee Catchment Management Authority, Parks Victoria, Department of Environment, Land, Water & Planning, Mildura Rural City Council, Northern Mallee Region Landcare, Traditional Owners and the thousands of hours volunteers contribute to Neds Corner Station.

Contact: Doug Robinson, Conservation Science Coordinator, Trust for Nature: (Tel: +61 1800 99 99 33.) Email: dougr@tfn.org.au; www.trustfornature.org.au

Photos: Trust for Nature

 

 

 

Habitat restoration at Snowy Adit, Kosciuszko National Park

Habitat restoration at Snowy Adit, Kosciuszko National Park

Key words: revegetation, habitat construction, montane, high altitude,fauna.

Introduction. Island Bend Downstream Spoil Dump, known as ‘Snowy Adit’, is one of approximately 30 former-‘Snowy Scheme’ sites in Kosciuszko National Park (KNP) that have undergone rehabilitation and restoration treatments in the last 10 years. The work is part of a program to remediate environmental risks associated with large volumes of rock dumped following underground blasting of tunnels and the cutting of benches for aqueduct pipelines constructed during the former hydro-electric scheme. At Snowy Adit, up to 950,000m3 of rock spoil was excavated and dumped. The footprint of the site is roughly 11 hectares, about 750m long and 150m wide.

Snowy Adit precinct 2008

Fig 1. Snowy Adit precinct 2008

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Fig 2. Snowy Adit precinct 2015

The site sits at an altitude of 1000m on the northern bank of the Snowy River at the junction with the Gungarlin River. The surrounding landscape is relatively intact, providing a reference ecosystem for the project, and occurs in a transitional zone between montane and sub-alpine vegetation. The dominant overstorey species is Ribbon Gum (Eucalyptus viminalis) with the sporadic occurrence of Candlebark (Eucalyptus rubida). The mid layer is dominated by wattle (Acacia species), and the shrub to ground layer includes Narrow-leaf Bitter Pea (Daviesia mimosoides), Burgan (Kunzea ericoides), Bidgee-widgee (Aceana nove-zelandiae), Carex (Carex appressa) and native grass (Poa helmsii). Within the rehabilitation site prior to works, the dominant species were weeds, aside from several shrubs of Burgan and the occasional Ribbon Gum.

Rehabilitation at Snowy Adit aims to restore a level of ecological function and stability by reducing erosion and re-establishing native vegetation. This gives long term protection to adjoining waterways and reduces the risk of weed invasion and habitat loss to the adjoining national park (Figs 1 and 2).

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Fig 3. Earthworks 2008

 

Integrating with natural regeneration on site

Fig 4. Integrating with existing vegetation on site

Works undertaken. The site was split into three management zones, with zones one and two progressively rehabilitated between 2008 and 2010, and zone 3 retained as an ongoing rock resource and storage area with some buffer planting. The rehabilitation techniques employed at each zone included:

  1. Earthworks to reduce steep embankments, provide track and bench access across the site for revegetation works and provide for future potential water flow across the site with a series of shallow swales and pond depressions (Figs 3 and 4);
  2. Ground disturbance to address highly compacted nature of existing surface;
  3. Removal of waste materials where possible – this included the recycling of 260 tonnes of metal that had been buried/dumped across the site;
  4. Addition of Coarse Woody Debris, primarily in windrows to provide wind shelter and thatch to hold straw and create microclimate. This material was sourced from logs and tree crowns removed during local trail clearing;
  5. Addition of compost production and water crystals to individual planting holes
  6. Planting 110,000 tubestock of 11 species from locally collected seed and cuttings in three stages;
  7. Mulching with rice straw;
  8. Weed control prior to pre works;
  9. Spreading of woodchip in weed prone areas such as access tracks and temporary nursery location.

After high initial browsing on planted seedlings by wallabies, deer and rabbits, most planting areas were progressively fenced. The steel 1.8 metre high fence had rabbit-proof netting to 1.05m high with a 300mm skirt pinned/rocked to ground, and hinge joint wire to 1.8m (Photo 4). Once in place, almost 100 percent plant establishment success was achieved.

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Fig 5. Flowering Acacia influencing nutrient status

Results to date. Soils and soil function. Monitoring has shown that three years after revegetation, soil infiltration, nutrient cycling and leaf litter values are still lower than the reference site, but soil stability measures are currently higher, possibly due to the role of young plants in binding the soil. Litter levels have understandably decreased since the original application of mulch and the amount of exposed rock has increased. It is expected that the growth of the revegetation will produce increasing amounts of litter and reverse this trend.

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Fig 6. Development of planted vegetation 6 years on

Vegetation. BioMetric http://www.environment.nsw.gov.au/papers/BioMetricOpManualV3-1.pdf was used to assess the condition of the vegetation along a 30m transect at 4 years after planting. This showed that the plantings had not yet developed to overstorey height but many of the Ribbon Gum had grown to midstorey height, providing a cover of 7.5%. The ground cover was mostly litter (52%) and rock (52%) with 2% bare ground. Native shrub cover of the ground layer was 20%, grasses 2% and forbs 8%. No exotic species were encountered along the transect so the total of 30% plant cover in the ground layer was all native. The number of woody stems was high (990) and similar to the control site. The level of exotic species incursion to the site was very low.

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Fig 7. High levels of coarse woody debris on site

Fauna. Rehabilitation works have greatly improved the habitat values of Snowy Adit, as evidence by increasing fauna recorded at the site. Pre- and post-treatment surveys have shown that, 5 years after revegetation commenced, the site is now used by at least sixty vertebrate species – 36 birds, 17 mammals, four reptiles and three frogs. Thirty-nine species were not recorded in the original 2006 survey, with 19 species (15 birds, two mammals and two frogs) attributed as a direct result of the rehabilitation works undertaken since 2006. Five threatened species were recorded in the rehabilitation area, with one additional listed species, the Powerful Owl (Ninox strenua), located in immediately adjacent forest. These threatened species were the Eastern Pygmy-possum (Cercartetus nanus), Eastern Bent-winged Bat (Miniopterus orianae oceanensis), Eastern False Pipistrelle (Falsistrellus tasmaniensi ), Gang-gang Cockatoo (Callocephalon fimbriatum ) and Flame Robin (Petroica phoenicea). The first three threatened species were not located in the original 2006 survey. The most outstanding discovery was the location of four Eastern Pygmy-possums within the fenced area of the rehabilitation area. Sixteen bird species now appeared to be either resident or regular visitors within the plantings rather than occasionally ranging into the area from adjacent forest; with nests of five species located. Several species were observed feeding flying dependent young juveniles within the planting area – such as the White-browed Scrubwren (Sericornis frontalis) and Rufous Whistler (Pachycephala rufiventris).

It is considered likely that, over time, some 29 species (23 birds, four reptiles and two mammal species) which were only recorded in adjacent forest and control sites in the current or original surveys will recolonise the area as the plantings continue to grow.

Lessons learned and future directions. The attention to detail in site preparation to create soil surface roughness and niches and microclimates in denuded and exposed sites at Snowy Adit is likely to explain the level of success achieved to date in terms of vegetation and habitat development. Constantly revisiting the site has also played an important role as it allowed measures to be taken to address overgrazing by both native and pest species. Taking the time to plan the works but also having flexibility to adapt and seek opportunities reaped benefits. A fortuitous supply of unwanted coarse woody debris and woodchip stockpiled at a nearby work depot also assisted with the establishment and growth of plants, controlled weeds and accelerated the return of native fauna using the for site as habitat.

Stakeholders and Funding bodies. The Rehabilitation of Former Snowy Scheme Sites Program was established from Snowy Hydro Limited funding and is managed by the Landforms and Rehabilitation Team in National Parks and Wildlife Service, NSW. Nicki Taws (Greening Australia Capital Region, Project Manager) conducted the vegetation monitoring. Martin Schulz conducted the fauna surveying and reporting.

Contact. Gabriel Wilks, Environmental Officer, National Parks & Wildlife Service NSW, PO Box 471 Tumut 2729, phone 062 69477070, Gabriel.wilks@environment.nsw.gov.au; Elizabeth MacPhee, Rehabilitation Officer, National Parks & Wildlife Service NSW, PO Box 471 Tumut 2729, Tel: +61 2 69477076, Email: Elizabeth.macphee@environment.nsw.gov.au.

Also read full EMR feature:Rehabilitation of former Snowy Scheme sites in Kosciusko National Park

Watch video short presentation by Liz MacPhee

Watch video short description of planting techniques Liz MacPhee

Watch video rediscovery of Smoky Mouse on rehab site Gabriel Wilks

EMR summary Restoration of Bourke’s Spoil Dump #2: https://site.emrprojectsummaries.org/2013/08/22/bourkes-gorge-spoil-dump-2-restoration-kosciuszko-national-park-2/

EMR summary Jindabyne Valve House Restoration: https://site.emrprojectsummaries.org/2013/08/20/jindabyne-valve-house-kosciuszko-national-park-nsw-2/

EMR summary Yarrangobilly Seed and Straw Production Area: https://site.emrprojectsummaries.org/2013/08/17/yarrangobilly-native-seed-and-straw-farm/

 

 

Stewartdale Nature Refuge koala habitat restoration in South Ripley, south east Queensland

Key Words: reconstruction, assisted regeneration, planning, koalas, conservation

Introduction: The Stewartdale Nature Refuge is located in South Ripley, south east Queensland on private land owned by the Sporting Shooters Association of Australia (SSAA). The 969 ha block contains live shooting ranges, large open areas dominated by pasture grasses, a substantial lagoon frequented by many bird species and extensive natural areas. The area being restored is 211 ha of dry sclerophyll vegetation, containing a number of Regional Ecosystems (REs) being restored through large scale planting (reconstruction) and assisted regeneration approaches. Its conservation value is heightened by the fact that it connects to the Karawatha Flinders Corridor, the largest remaining stretch of open eucalypt forest in south-east Queensland.

Condition ranges from large degraded areas (i.e. pasture) to native vegetation that contains both regrowth and remnant dry sclerophyll. All areas were impacted by varying levels of weed infestation due to previous clearing and ongoing disturbance from cattle grazing. Natural disturbances such as regular fire and periodic floods have also contributed to disturbance at the site. More than 30 weed species impact the project area at varying levels and the species and impacts vary with the condition of the land. Open areas were dominated by pasture grass such as Setaria (Setaria sphacelata) and Rhodes grass (Chloris gayana) in addition to fast growing annuals, although infestations of Leucaena (Leucaena leucocephala), Prickly Pear (Opuntia stricta) and large clumping Bamboo (Bambusa sp.) also required significant control efforts. In more forested areas (and underneath isolated remnant trees) weed species included Lantana (Lantana camara), Creeping Lantana (Lantana montevidensis), Corky Passionfruit (Passiflora suberosa), Easter Cassia (Senna pendula var. glabrata), Siratro (Macroptilium atropurpureum) and exotic grasses, annuals and groundcovers.

The aim of the project is to restore, native plant communities present within the Stewartdale project site to support local koala populations. Our goals are to:

  • Repair native vegetation including the structure, integrity and diversity to support koala populations
  • Strengthen the resilience and regenerative capacity of native vegetation
  • Restore and expand native regrowth vegetation by controlling weeds
  • Maintain the project site so weeds do not negatively impact the development and recovery of native vegetation
  • Protect drainage lines, gullies and slopes from erosion
  • Protect and enhance the water quality of Bundamba Lagoon
  • Construct fauna friendly fencing across the site with the aim of protecting planted trees from herbivory
  • Reduce the risk of fire moving through the site and impacting restoration works by conducting strategic slashing activities to reduce fuel loads.

Planning. A restoration plan was developed after detailed site assessments and negotiations with the landholder, land manager and state government were finalised integrating Nature Refuge conditions and current land use and future management requirements. The site was divided into zones and sub-zones to assist directing works including applying a range of restoration approaches – i.e. assisted regeneration and reconstruction (‘revegetation’) and several planting models and species mosaics to different parts of the site. Detailed maps were produced for each zone and included information such as the location of all tracks, fences, assisted regeneration zones, wildlife corridors, planting areas according to each RE and numbers of species and plants to be installed per zone. The plan also included detailed information on restoration approaches; weed control at all stages of the project; seed collection and propagation; site preparation including the specifications and location of all fencing, tracks, rip lines and areas of concern (i.e. identified hazards across the site); how to carry out all works in each zone; site maintenance requirements for 5-7 years; and monitoring requirements.

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Fig 2. Preparation for planting  at Stewartdale Nature Refuge.

PP2b after planting Mar 2016

Fig 2. After planting to support local Koala population, Mar 2016.

Works to date. Site preparation commenced with the collection of seed from on and around the wider property and surrounds ensuring that all species to be planted were collected from a minimum of 10 widely spaced parent trees. Primary weed control started with the control of weeds in the 65 ha of assisted regeneration zones and the control of other woody weeds across reconstruction areas in preparation for slashing and other activities. More than 18 km of fauna friendly fencing (i.e. no barbed wire) was installed to protect planted stock from browsing by large herds of macropods and cows. Two large corridors were retained for fauna to reach Bundamba lagoon from different parts of the regional corridor as it is an important resource for many local and migratory fauna. Slashing across open areas was commenced and followed by the installation of rip lines to alleviate soil compaction and assist efficient planting activities. Weeds and pasture grasses were then sprayed out along all rip lines. 114 000 koala food and shelter trees were planted according to the RE for each section and according to the local conditions (i.e. whether it was low lying, on a ridge or near infrastructure). Some additional frost resistant and local Acacia species were also added to particularly frost prone areas to assist the development of a canopy and the protection of developing vegetation.

The 114 000 tubestock were installed over a 7 week period with the last stems being planted in April 2015. All trees were fertilised and watered at the time of planting and where possible, slashed grass spread across the rip lines to assist retaining moisture and slowing weed regrowth. (Follow-up watering was applied to all planted stock between September and October 2015) Nearly 2000 (1 m high) tree mesh guards were installed to protect planted stock in fauna corridors.

Series shot 1.1

Careful spot spraying to reduce weed while protecting natives

Series Shot 1.2

Growth of saplings is improved without competition.

Results to date. As of March 2016, weeds have been significantly reduced across the 65 ha of assisted regeneration areas. Unfortunately a wildfire fire went through approx. a third of the project area after primary and follow up weed control works had been completed. Fortunately the event was prior to planting though the fire did reduce the number of trees regenerating in assisted regeneration patches as many were too young to withstand the fire. New germinations are however occurring and the level of native grasses, groundcovers and other native species have increased due to ongoing weed control efforts.

Despite heavy frosts in winter 2015, a flood event in May 2015 (150 mm of rain fell in 1.5 hours) and now an extended dry period, the planting is developing well with the average height of trees at over a metre tall and mortality under 5%. Weed control is continuing across the project site with efforts currently concentrating on the control of many annual weeds such as Cobbler’s Peg (Bidens pilosa), Balloon Cotton (Gomphocarpus physocarpus) and Stinking Roger (Tagetes minuta) and many exotic grasses such as Setaria (Setaria sphacelata) and Rhodes grass (Chloris gayana) to reduce competition to planted stock. Assisted regeneration areas are being joined up to planting zones wherever possible to further assist the development of the site.

It should also be noted that Birds Australia have recorded 69 bird species on site.

Ongoing works: Regular maintenance continues on the site with the control of weeds particularly along rip lines where weed germination and growth is rapid. Slashing is also regularly done between the rip lines and along tracks and fence lines to assist access around the site and the management of fuel loads and therefore wildfire across the site. It is expected that the time it takes to complete each maintenance rotation will begin to reduce as plants become more established and start to develop a canopy.

Weed control will also continue in all assisted regeneration zones and is also expected to reduce with the development of native vegetation structure and diversity together with the reduction of the weed seed bank. Ongoing slashing, fence maintenance and monitoring will continue for another 3-5 years though the exact time period will be determined by the State government.

Monitoring including soil moisture readings, transects to assist determining survival rates across the site and photographic monitoring is regular and further supports 6 monthly reporting requirements.

Stakeholders and funding bodies: Department of Environment, Heritage and Protection, Queensland State Government; Sporting Shooters Association of Australia (SSAA). Photos: Ecosure.

Contact Information: Jen Ford (Principal Restoration Ecologist, Ecosure TEl: +61 (0)7  3606 1038.

 

Restoration at Numinbah Conservation Area, City of the Gold Coast, Queensland

Key Words: assisted regeneration, restoration planning, conservation

Introduction: Numinbah Conservation Area, located in the hinterland of the Gold Coast in south-east Queensland, is one of many natural areas managed by City of Gold Coast’s Natural Areas Management Unit (NAMU). The 598 ha property contains 12 Regional Ecosystems (REs) ranging from sub-tropical and dry rainforest to dry and wet sclerophyll types; and include riparian zones, steep areas, gullies and rocky outcrops. Its conservation value is heightened by the fact that it connects to other reserves including the World Heritage areas of Springbrook.

Condition ranges from large degraded areas (i.e. pasture) to native vegetation that contains both regrowth and remnant areas. All areas were impacted by weeds due to previous disturbance from logging and subsequent cattle grazing. More than 35 weed species impact the site at varying levels with the most notable species across the site being Lantana (Lantana camara). Edges are impacted by exotic vines such as Glycine (Neonotonia wightii), the understorey by many herbaceous weeds such as Mistflower (Ageratina riparia) and rainforest zones by persistent weeds such as Coral Berry (Rivina humilis) and Passion Vines (Passiflora spp.) to name a few. Approximately 60 hectares of open area are dominated by pasture grasses and other weeds.

The aim of the project is to restore, to the extent possible, the structure, function, dynamics and integrity of the pre-existing vegetation and the sustaining habitat that is provided. Our goals are to:

  • Improve the health of vegetation and habitat types across the site
  • Improve connectivity for flora and fauna
  • Reduce fuel levels in fire prone ecosystems and the risk of hot fires sweeping through the site and wider landscape
  • Increase the resilience of the site
  • Improve water quality
  • Increase the health, populations and distribution of threatened species – flora and fauna
  • Reduce the need for weed control maintenance over time i.e. to a level of minimal maintenance
  • Provide nature based recreational opportunities and environmental education along this section of the Gold Coast Hinterland Great Walk

Planning. An ecological restoration plan was developed after detailed site assessments and the site was divided into precincts, zones and sub-zones to assist directing works. Information in the plan included species lists, weed control information, maps and detail on how to restore each area and progressively link zones. A detailed fire management plan was also developed for the site that took into account wildfire mitigation, restoration zones, the location of threatened species, site objectives, REs including their recommended fire regimes, and the capacity of areas to regenerate.

Works to date. Works over the last 9 years have covered more than 190 ha. The main approach to restoration has been via assisted regeneration consisting mainly of large scale weed control and the fencing of areas to reduce the impact of cattle. Further works have involved planting a section of creek to assist stability and connectivity across a section of the site; and the propagation and translocation of four threatened flora species (details not disclosed for security reasons).

Where low intensity fuel reduction burns were conducted in dry sclerophyll vegetation, timely follow up weed control was applied to ensure re-shooting Lantana, Molasses Grass (Melinis minutiflora) and other weeds did not fill gaps and to support the colonisation and growth of native vegetation. In remnant and regrowth vegetation, systematic weed control using a range of techniques has been applied. E.g. large areas of Lantana were controlled using three techniques: cut, scrape and paint where it was in close proximity to native plants; over-spraying after isolating infestations; and, spot-spraying when it germinated or was re-shooting. Weed species were continually suppressed to ensure native species germinated and grew to a point where most gaps have been filled with native vegetation. As each area developed and maintenance reduced, efforts were put into continually expanding the work fronts.

A propagation and translocation project was also implemented in partnership with Seqwater. More than 1150 individuals (four species) have been propagated, planted into their particular niche and have been monitored and reported on annually. This will continue until all species are considered to be self-sustaining i.e. flowering, fruiting and reproducing.

(a)NCA8n_20080502

(b)NCA8n_20080827

(c) NCA8n_20090716

(d)NCA8n_20100625

(e)NCA8n_20110630

(f)NCA8n_20151130

Figure 1, (a-f) represents an annual sequence of recovery after control of Lantana and subsequent weed at one photopoint from 2008 to 2011, with the last photo taken in 2015. The results reflect accurate and timely weed control to support the recovery of native vegetation. (Photos: City of Gold Coast)

Results to date. As of July 2015, weeds have been significantly reduced across the 190 ha treated area to a point where maintenance is being applied, with some areas requiring little to no maintenance. In a number of areas this reduction of weed has also significantly reduced fuel levels.

Increased abundance and diversity of native vegetation has occurred across a range of ecosystem and habitat types within the reserve. Open areas once dominated by dense Lantana have taken approx. 3 years to naturally regenerate with a range of pioneer, early secondary and later stage rainforest species (Figs 1-3). Many of those areas now include continuing recovery of later stage species and contain a large diversity of seedlings, groundcovers and ferns. More diverse communities have recovered with a large range of species (depending on the ecosystem / ecotone) and support a diversity of fauna species. Works in four of the larger precincts have now joined up and weed control works are continuing to expand all regenerating areas.

More than 7000 plants installed along the open riparian stretch are establishing with native species regenerating amongst the planting. After approx. 7 years the average height of the planted canopy is approx. 5-7m tall.

Ongoing works: All current work zones are being continuously extended ensuring progress made is maintained. The open area (e.g. paddock) is being reduced over time as vegetation is encouraged to expand (i.e. by continuing to control weeds to past the drip lines of all native vegetation). Fences that currently contain cattle (i.e. to assist managing open areas for access, fire management and to ensure funds are spent in more resilient areas) are being moved to continue to reduce the size of highly degraded areas. Fire management, large scale weed control and the monitoring and evaluation of threatened species, together with fauna surveys, is continuing.

Stakeholders and funding bodies: Natural Areas Management Unit (NAMU), City of Gold Coast and Seqwater. Contact Information Paul Cockbain, Team Leader Restorations +61 7 5581 1510

 

Post-sand extraction restoration of Banksia woodlands, Swan Coastal Plain, Western Australia.

Deanna Rokich

Key words: research-practice partnership, adaptive management, smoke technology, cryptic soil impedance, topsoil handling.

Figure 1. Examples of undisturbed Banksia woodland reference sites.

Introduction. Banksia woodlands were once a common and widespread feature of the Swan Coastal Plain, Western Australia (Fig. 1); today less than 35% of the original Banksia woodlands remain in metropolitan Perth. When sand extraction activities were permitted over 25 years ago, Hanson Construction Materials opted to go well beyond the statutory minimum requirement of re-instating local native species. Instead, Hanson committed to meet the challenge to return post-sand extracted sites (Fig. 2) to an ecosystem closely resembling the pre-disturbance Banksia woodland. To achieve this high resemblance to the reference ecosystem, Hanson operations sought the assistance of the Science Directorate team within the Botanic Gardens and Parks Authority in 1995. BGPA developed and implemented a research and adaptive management program with Hanson, resulting in a collaboration involving graduate and post-graduate student research programs into key facets of Banksia woodland ecosystem restoration, application of outcomes into restoration operations, and finally, restoration sites that are beginning to mimic reference sites (Fig.3).

Prior to the partnership, species richness and plant abundance, and thus restoration success, was limited in the rehabilitation. Research and adaptive management subsequently focused on improvements in soil reconstruction; topsoil management; seed germination enhancement (including smoke technology); seed broadcasting technology and whole-of-site weed management.

Monitoring. BGPA scientists have been undertaking annual plant monitoring of Banksia woodland restoration activities within reference and restoration sites for ca 15 years. This has resulted in data-sets on seedling emergence and plant survival within a range of sites, culminating in the development of annual performance criteria and ultimately, the ability to measure restoration performance in the short (e.g. from seedling emergence) and long-term (e.g. from plant survival).

Fig2d

Figure 2. The greatly reduced Banksia woodland sand profile following sand extraction, with topsoil being spread onto the pit floor.

Results. Consolidation of ca 15 years of data from >50 sites (encompassing a range of topsoil quality and climatic conditions) has revealed that stem density and species richness fall into three levels of restoration:

  • good restoration quality (high topsoil quality and favourable climatic conditions).
  • medium restoration quality (poor topsoil quality or unfavourable climatic conditions).
  • poor restoration quality (poor topsoil quality and unfavourable climatic conditions).

The integration of key research areas has resulted in:

  • Identification of first year species re-instatement being the blueprint for long-term species re-instatement.
  • Observation of cryptic soil impedance and extremely high plant loss in the standard ‘topsoil over overburden’ profile during the 2nd summer following restoration, but higher plant re-instatement and better ecosystem dynamics in the long term.
  • Improvement in seedling re-instatement, illustrated by perennial species return increasing from less than 10% to more than 70% (i.e. >100 perennial species), and stem density return of >140 perennial plants per 5m2 in Year 1, primarily due to improved topsoil handling methods – i.e. good quality, fresh and dry topsoil.
  • A ten-fold increase in the stem density of seedlings derived from direct-seeding due to innovative seed coating technology, delivery to site technology and sowing time optimisation.
  • Trebling of seedling recruitment success due to application of smoke technology.
  • Minimised weed invasion through the use of good quality and fresh topsoil, burial of the weed seedbank and prompt active weed management.
FIg3a

Figure 3. Restoration sites after 8 years, illustrating the return of the Banksia trees.

Implications for other sites. The post-sand extraction sites have provided important lessons and information about the management and restoration needs of Banksia woodlands – e.g. a high level of intervention is necessary, whilst cross-application of general restoration principles are not always possible for Banksia woodlands – useful for all those involved with managing and restoring Banksia woodland fragments within the broader Perth region.

Current and future directions. Hanson is committed to ongoing improvement through research – continually testing and employing new research techniques, programs and equipment that are recommended from BGPA research programs.

Post-sand extraction restoration practices now involve:

  • re-instating the soil profile in its natural order of topsoil over overburden, in spite of the cryptic soil impedance witnessed in the overburden in the 2nd summer following restoration;
  • striving for highest seedling establishment in the first year of restoration, prior to onset of soil impedance;
  • stripping and spreading only good quality (free of weeds), fresh and dry topsoil;
  • conserving topsoil by a strip:spread ratio of 1:2 (i.e. stripping over 1ha and spreading over 2ha);
  • burying direct-sown seeds given that seed displacement from wind and invertebrate activity is prolific during the typical seed sowing season; and
  • ceasing the common practices of mulching sites and tree-guarding plants as they provide negative or no benefits.

The partners are considering re-doing sites rehabilitated during 1991-1994, prior to research, in order to improve species diversity.

Acknowlegments: Botanic Gardens and Parks Authority and Hanson Construction Materials are the key parties in this project; involving many individual managers, researchers and students.

Contact: Deanna Rokich – Deanna.Rokich@bgpa.wa.gov.au

Seed production and direct seeding to restore grassy understorey diversity at Mount Annan, NSW.

Peter Cuneo, Jordan Scott and Katharine Catelotti

Key words: direct seeding, grassy woodland restoration, seed production areas, Cumberland Plain woodland

Need for restoring grassy diversity. The rapid spread of African Olive (Olea europaea ssp. cuspidata) in the Cumberland Plain region of western Sydney in recent decades is now a significant conservation concern (Figs 1 and 2). Cumberland Plain Woodland (CPW) is now listed at the state and federal level as a critically endangered ecological community, and African olive invasion is recognised as the greatest invasive threat to CPW, and listed under the NSW TSC Act as a Key Threatening Process.

Dense monocultures of African olive are now established at a landscape scale in western Sydney, and there has been considerable use of mechanical mulching (‘forest mowing’) to control these highly degraded CPW remnants/monocultures (Fig 3). Often only remnant trees remain, and once these dense olive infestations are controlled, land managers are faced with several years of follow up olive control, degraded native soil seedbank and a profusion of annual weeds.

The Australian Botanic Garden, Mount Annan (ABGMA) has completed over 40 hectares of mechanical control of African Olive since 2009. Recent research (Cuneo & Leishman 2015) has indicated that a ‘bottom up’ approach restoration using native grasses as an early successional stage has potential to restore these transitional landscapes and achieve a trajectory towards CPW.

Hillside African olive invasion

Fig 1. Hillside African Olive invasion

Beneath dense olive canopy

Fig 2. Nil biodiversity beneath dense African Olive canopy

Olive mulching machine

Fig 3.  Olive mulching machine

Like many landscape scale ecological restoration projects ABGMA faces a shortage of native grass seed, however a successful NSW Environmental Trust application provided the funding support to develop a 1500 sq metre native grass seed production area as part of the Australian PlantBank landscape. The key objective was to grow high quality weed free native grass seed (of known germinability) to direct sow on degraded African olive sites where the native grassy understory had been lost.

Seed production area. The seed production area was established by tubestock planting of four key local grasses, Dichelachne micrantha (Plume grass), Microlaena stipoides (Weeping meadow grass), Chloris truncata (Windmill grass) and Poa labillardieri (Tussock grass) (Figs 4 and 5). Seed was wild source collected from CPW and grasslands within ABGMA, which provides a reference vegetation type and condition to guide restoration. The seed production area which was irrigated and fenced to exclude rabbits was highly productive, even during the first summer season. Both hand and mechanical harvesting were used, and the total output over the 2014/15 summer was impressive 118 kg of seed material harvested. All seed batches were germination tested at PlantBank which indicated a total output of over 13 million viable seeds from the first harvest season.

Planting Seed prod area

Fig 4. Planting out seed production area

 

Plumegrass

Fig. 5.  Plumegrass in seed production area, almost ready for harvest

Direct seeding of grasses. Restoration challenges included large areas, profuse annual weeds and competitive olive seedlings on the transitional post-olive sites. A decision was made to focus the direct seeding across one fifth of the treatment area in a series of cultivated 2m wide strips at 8m spacing. The strips were created along contours to limit the erosive potential of the prepared areas. These seeded strips could then be managed in a similar way to surrounding cleared areas with broadleaf selective herbicide and slashing.

Seeded grass strips were prepared using a small track machine with surface tilling attachment to provide good soil/seed contact (Fig 6). Seed material (seed/stalks) were combined with compost (Fig 7) and sand and hand broadcasted. In an effort to create an ‘in situ’ seed production area and robust native grass populations, harvested grass seed was then used to high density (up to 3300 seeds/m²) direct sow a total of 5km x 2m wide strips throughout 5 hectares of cleared African olive sites at ABGMA in March 2015.

Favourable conditions during autumn 2015 resulted in excellent field germination, with established seedling densities of up to 608 seedlings/m² observed after 10 months (Fig 8). The combination of surface tilling and dense sowing rates has resulted in a dense and competitive grass layer, however some further broadleaf weed control along the strips will improve long term grass density and establishment.

These native grass strips will provide a ‘nucleus’ grass seed source for these degraded areas, maintaining soil stability, improving ecological resilience and accelerate the regeneration of these degraded areas.

Direct seeding strips

Fig 6. Direct seeding strips prepared

Mixing bulk native grass seed

Fig 7. Mixing bulk native grass seed

Seed strip established2comp

Fig 8. Seed strip established after one year

Lessons learned. Using known quality seed and achieving seed/soil contact through surface tilling was important to success, as cleared olive areas have a heavy mulch layer which limits seed contact. The use of both C3 and C4 grasses in the direct seeding mix worked well and is recommended, particularly for autumn sowing where cool season C3 can establish a quick cover followed by C4 grass establishment in summer. Some mechanical wild grass seed harvesting is also done at ABGMA, however practitioners should be aware of the risk of grassy weed contamination. Overall the project was relatively labour intensive, but some mechanisation of seed spreading could be achieved with a compost spreader. Steep terrain at ABGMA is a limiting factor for some machinery, and hand broadcasting can be a practical option.

Future directions would include scaling up the size of seed production areas, and refining mechanical harvesting techniques. Grass seed strips will be progressively managed, and seed either mechanically harvested or slashed to spread seed across the site. Once grasses are well established, the next phase will include direct seeding of CPW shrubs and trees. The well prepared and presented seed production area with mass plantings of native grasses, attracted considerable visitor interest at ABGMA and became a focus for several practitioner field days on olive control and ecological restoration.

Acknowledgements: Implementation of this NSW Environmental Trust project has relied significantly on working with industry partners, Greening Australia (Paul Gibson-Roy, Samantha Craigie, Chris Macris), Cumberland Plain Seeds (Tim Berryman) and Australian Land & Fire Management (Tom McElroy) who have bought additional technical expertise as well as on-ground implementation.

Contact person: Dr Peter Cuneo, Manager Seedbank & Restoration Research, Australian Botanic Garden, Mount Annan, NSW Australia. Locked Bag 6002, Mount Annan NSW, 2567. Email: peter.cuneo@rbgsyd.nsw.gov.au   Phone: +61 (2)46347915

Watch RegenTV Video : Seed production area

Read full EMR feature: http://onlinelibrary.wiley.com/enhanced/doi/10.1111/emr.12139

BG & CP website: https://www.rbgsyd.nsw.gov.au/Science-Conservation/Our-Work-Discoveries/Natural-Areas-Management/Restoring-test