Category Archives: Restoration & management theory

Facilitated natural regeneration in the ‘Middle clearing (Setaria plots)’ of Minyumai Indigenous Protected Area, The Gap NSW

Posted on 3 November 2023 by | Comments Off on Facilitated natural regeneration in the ‘Middle clearing (Setaria plots)’ of Minyumai Indigenous Protected Area, The Gap NSW

Minyumai Rangers

Figure 1. Aerial view of the Setaria-dominated clearing at Minyuma IPA prior to restoration work . The trial area arrowed is the location of the preliminary trial of herbiciding plus fire followed by regular spot spraying of weed regrowth. The project was then expanded to much of clearing to the left of the artificial drain running through the centre of the site (Photo Minyuma IPA)

Introduction. ‘Minyumai’ is an approx. 2000ha property owned by Minyumai Landholding Aboriginal Corporation (MLHAC) and managed by the MLAC board and the Minyumai Rangers. The property is located on the far north coast of NSW, adjacent to Bundjalung National Park and Tabbimoble Nature Reserve and was dedicated as an Indigenous Protected Area (IPA) in 2011. 

The property is largely comprised of native ecosystems, including five Endangered Ecological Communities (EECs), however it has a history of grazing in largely three sizeable clearings.  The largest and most degraded of these clearings (the ‘middle clearing’) (Figs. 1 and 2) became known to the Rangers as the ‘Setaria plots’ as it was almost completely devoid of trees, was dominated by the introduced pasture grass Setaria (Setaria sphacelata) and was subsequently divided into multiple plots for treatment and monitoring.

Figure 2. Closer view of the density and cover of Setaria at the site prior to treatment. (Photo Minyuma IPA)

The purpose of the work in the Setaria plots is to convert the vegetation from weed dominance to dominance by native species of the site’s prior ‘Swamp sclerophyll forest on coastal floodplains’ EEC. The project started in 2014 and is an ongoing part of the Ranger’s regular works program. 

Works undertaken. After a successful trial sponsored by Firesticks in an adjacent area, a facilitated natural regeneration approach was adopted in the Setaria plots, supplemented by some tree planting. While there were little or no above-ground natives evident among the mature Setaria at the start of the project (Fig 2), the Firesticks trial showed that the use of fire followed by precision weed spraying would result in at least some regeneration of native ground covers from the soil seed bank.

Figure 3. Firebreaks were installed at the site prior to spraying and burning and remain maintained to allow for ongoing use of fire during over time should it prove beneficial. (Photo Minyuma IPA)
Figure 4. Minyumai Rangers and visitors from a neighbouring IPA running a burn on the site. (Photo Minyuma IPA)

The plot-by-plot approach subsequently adopted involved creating firebreaks, overspraying the mature setaria with 1% glyphosate and subsequent burning of the dried weed biomass (Figs 3 and 4).  Subsequent follow-up spot-spraying was then systematically and regularly carried out.

Monitoring.  The project offered an opportunity to separate and compare burn and spray treatments with spray-only treatments – i.e.  all plots (except untreated controls) were subjected to systematic weed management but some were additionally burnt.  Species counts and cover was measured at 2 years of age and again at 4 years of age – with the ground stratum monitored using 15 quadrats (7 burn+spray, 6 spray only and 3 controls) and woody cover monitored using 18  (20m) transects (line intercepts).

Figure 5. Photopoint monitoring showing changes at the site over a 3 year period showing treatments and gradual regeneration of natives. (Photos Minyuma IPA)

Results to date.  While the initial follow up treatments revealed extensive weed, this rapidly transitioned to native dominance over time (Fig 5) and with fairly rigorous herbicide treatment of all weed by the Rangers.  The site developed high levels of cover within 18 months. A total of  37 native species were recorded over the four years (including 5 trees, 2 shrubs,  1 vine, 18 forbs, 7 sedges and 4 grasses) .  A total of 26 weed species (1 shrub, 14 forbs, 2 sedges and 9 grasses) occurred and while weed cover reduced over time ) most species of weed remained present in the system.  

The quadrat data showed that the fire plus spot-spraying treatment resulted in improved native cover in the ground stratum (scoring an average of 3.38 on a 5 level cover scale)  compared to spot-spraying alone (scoring an average of 2.17 on the 5-level cover scale) with the controls remaining in the lowest cover level.

Transect monitoring of woody species cover over time showed a significant increase in tree cover after both fire plus spray (n=5)  and spray alone (n=9) treatments compared to the untreated controls (n=4) but there was no significant difference between the burn plus spray and spray only  treatments, which is understandable as none of the tree species form soil seed banks.

Figure 6.  Drone photo of the same quadrats from the air in August 2023, nine years after the work commenced. The dense green tree growth in the middle of the photo is all regrowth on the treated plots. Between this area and the intact Paperbark forest in the further distance there is a band of untreated land still dominated by Setaria and without native colonisation. (Note the Eucalypt circled is the same Eucalypt in the right hand background of the photos in Figure 5.)   (Photo G. Little)

Changes over time. The sedges, which were initially abundant in the understorey,  became less abundant over the two readings. Native grasses were initially far less common but increased over time, and 10 years on are still far less prevalent than sedges, which makes sense considering the wetland nature of the site.

Some  forbs, such as Buttercups (Ranunculus spp.), Gotu Kola (Centella asiatica), Pennyworts (Hydryocotyle spp.), Kidney Weed (Dichondra repens) and Native St Johns Wort (Hypericum perforatum) became frequent or abundant and remained so over the monitoring period. while other forbs such as Grass Lily (Murdannia graminea), Ludwigia (Ludwigia and Native Bluebell (Wahlenbergia sp.) remained uncommon or even rare.

Over the 10 years since the project began, the tree species Swamp Box (Lophosptemon suaveolens), Swamp Oak (Casuarina glauca) and Broad-leaved Paperbark (Melaleuca quinquinervia) have all become markedly more abundant over time through colonisation from the surrounding forest (Fig. 6) – with natural regeneration far outweighing any tree planting efforts made at the start of the project.  Forest Red Gum (Eucalyptus tereticornis) did not however increase from the remnant tree on site nor did planted seedlings of this species survive.   

Lessons learned and future directions.  When comparing the treated areas with untreated areas it is clear that the native tree colonisaton is confined to the treated areas. Although the treated areas developed high native herbaceous cover it is likely that the open niches created by the weed control and fire allowed colonisation by trees, while the dense Setaria cover prevented regrowth. 

A major challenge has been the presence of wild cattle on the property that have proved resistant to capture. This required electric fencing of the site for some years to avoid damage to plantings, although natural regeneration has now overtaken the plantings.

Critical to success was rigorous follow up prior to the weed reseeding.  Complete avoidance of reseeding was not always possible due to funding limitations or personnel changes. This has resulted in some reinvasion of Setaria in some of the plots, although the Rangers continue to manage the site well. 

As the mown firebreaks are still in place, there is potential for cool fire to be reintroduced into the site (followed by further weed control) should this be considered ecologically beneficial.  The site may also benefit from a project (being conducted in collaboration with Nature Glenelg Trust) to fill in the artificial drain visible in Fig 1.

Stakeholders and Funding bodies.  We acknowledge the valuable contributions of all the Minyumai IPA Rangers, particularly the early leadership of Minyumai Rangers, Daniel Gomes, Justin Gomes and Belinda Gomes. The Commonwealth Government’s IPA program funded the delivery of biodiversity management services by MLHAC, and funding and advice for the fire trials was provided by the NSW Nature Conservation Council’s  Firesticks initiative, with advice from Oliver Costello and Richard Brittingham. Tein McDonald advised on techniques and monitoring and Andrew Johnston provided training for the Minyumai Rangers in the first years of the project.

Contact: Mary Wilson, Minyumai Land Holding Aboriginal Corporation. Email: <admin@minyumai.org.au>

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Posted in agricultural lands, Assisted regeneration, Bush regeneration, Fire Ecology & Management, Indigenous land & sea management, New South Wales, Restoration & management theory, Techniques & methodology, Threatened species & communities, Weed issues & solutions, Wetland

Shorebird habitat restoration in the Hunter Wetlands National Park

Posted on 25 August 2023 by | Comments Off on Shorebird habitat restoration in the Hunter Wetlands National Park

By Tom Clarke

Figure 1. Contractors felling mangrove trees to restore migratory shorebird habitat structure at Stockton Sandspit.

Introduction. Thirty-seven species of migratory shorebirds regularly visit Australia, with all but one spending up to 6 months of each year here. Globally, populations of some migratory shorebirds have declined by 80% over the last 30 years largely due to habitat destruction and disturbance along the East Asian-Australasian Flyway. Within Australia, degradation of feeding and roosting habitats and disturbance are the major threats. Shorebirds need access to safe roosting places. Typically, a favoured roost is close to feeding areas, has a wide-open space and a clear view of the water. A clear view is needed for predator avoidance. A major issue for shorebirds in the Hunter Estuary, indeed for the entire flyway, is having access to several roosts so that alternative sites are available when conditions and levels of disturbance become intolerable at the preferred roost.

In the late 1990s it became obvious that vegetation encroachment was degrading major roost sites in the Hunter Estuary. Of particular concern was the viability of Stockton Sandspit, a shorebird roost site of national importance. Mangrove encroachment along the beachfront was creating a wall of vegetation and effectively blocking the view of the water. Woody weeds were also encroaching on the roost area resulting in a large decline in shorebird numbers using the roost site.

Mangrove encroachment has been documented in several estuaries along the east coast of Australia. Halting encroachment is not an option but managing specific areas that are important for shorebirds is achievable. This project involves the removal of mangroves adjacent to favoured roosting sites to maintain low, open spaces with a clear view of the water, with the intent of maintaining the sites  for shorebirds as long as they keep turning up. The potential recovery of coastal saltmarsh in these sites is an added bonus as saltmarsh is an endangered ecological community.

Figure 2.  Main shorebird habitat restoration sites in Hunter Wetlands National Park.

Works undertaken. Mangroves are normally protected vegetation by law. After it was agreed by various stakeholders that mangroves should be cleared from Stockton Sandspit, a permit to remove mangroves was applied for from Department of Primary Industries (Fisheries). The initial permit allowed for the removal of mature mangroves from an area of less than 1 hectare. This primary work was carried out by contractors (Fig. 1). The funding agreement required matching volunteer effort. Initially, volunteer work involved Hunter Bird Observer’s Club (HBOC) monitoring the shorebirds, but this was quickly augmented by on-ground work to remove woody weeds (including Lantana Lantana camara, Bitou Bush Chysanthemoides monilifera ssp. rotundata and Telegraph Weed Heterotheca grandiflora) and reduce the density of native shrubs (including Acacia spp, Banksia spp. and Leptospermum spp.) from the roost area. Weeding also aimed to remove exotic rushes from a small area of saltmarsh. Following initial success, other shorebird roost sites in the Hunter Estuary with similar threats were added to the program (Fig. 2). These additional areas were selected using data from the shorebird monitoring being conducted by HBOC. At each site, an initial primary effort by contractors is followed up by HBOC volunteers and others. The project has been running continuously since 2002 and represents the HBOC commitment to caring for these endangered birds.

Over 10,900 volunteer hours has been accrued to date through the efforts of over 480 persons and the program is ongoing. Today, the project maintains nearly 150 hectares of shorebird habitat in Hunter Wetlands National Park. From March through to July each year, a program of works is scheduled to take advantage of favourable tides to access work areas. These cooler months are better for working in exposed areas and are when the population of migratory shorebirds is at its lowest. Removal of mangrove seedlings takes up most of the ongoing volunteer effort (Figs 3-6). The level of recruitment of mangrove seedlings varies from year to year and site to site. Factors such as tide height, wind direction and flood levels at the time of seed-drop affect the distribution of the seeds. Seed-drop usually occurs from the end of August through to early November with the majority falling through September. However, over the eighteen months of wet weather following the prolonged drought that ended in early 2020, mangrove seeds were washing up every month of the year. This required a massive effort to clear mangrove seedlings from all the sites in 2022. Thankfully the effort required in 2023 was back at a sustainable level.

Figure 3. Intrepid Landcarers cutting mangroves on Smith Island. (Photo T. Clarke)

Figure 4. Volunteers sweeping the marshes at Stockton Sandspit. (Photo T. Clarke)

Results to date. Removal of fringing mangroves and woody weeds from the roost area had an immediate positive effect. Most of the shorebirds quickly re-occupied Stockton Sandspit. This continues to be the case with Stockton Sandspit being one of the main daytime roosts used in the Hunter Estuary. Similar success has occurred at other sites but has not been quite as outstanding. These sites tend to be used by smaller aggregations of birds but are complementary to the Stockton Sandspit as different shorebird species prefer them. Some of the additional sites are frequently used as back-up roost sites when the preferred site is suffering unusually high levels of disturbance, often due to human activity.

Figure 5. Final sweeps over Milham Pond by Hunter Bird Observers Club volunteers in 2022. (Photo T. Clarke)

Figure 6. Mass drop of mangrove seeds happens every year at Stockton Sandspit and other places. Six months later the surviving seedlings are removed by volunteers. (Photo T. Clarke)

Lessons learned and future directions. Working on the inter-tidal areas has required that we develop an understanding of how the estuary system operates. In the early years lots of tide notes were collected for each site as well as shorebird movements. Utilising favourable tides gives better access and improves efficiency. Understanding certain shorebird behaviours also improves our efficiency. Quite often, a couple of forward scouts in the form of godwit or curlew will fly over a roost site on an inspection loop prior to the main rush of the various flocks. This is the signal for workers that it is time to vacate the site.

Many techniques and a variety of hand tools have been trialled with differing levels of success. Hand-pulling the seedlings has proven to be the most efficient. We have found that it is possible to manage the mangroves without the use of chemicals. Cutting stems lower than the next high tide results in the stumps being immersed and the tree dies. This also works for seedlings that are snapped-off. In situations where the substrate is firm enough, seedlings can be snapped off at ground level using a hoe. However, this method doesn’t work in soft mud as the plant bends away rather than breaking. Where seedling recruitment is dense, a battery-powered brush cutter has been utilised. This method was very useful during the year of continuous seeding.

While the initial work was motivated by a sense of obligation to intervene, the ongoing work provides positive feedback that maintains the energy and brings much satisfaction to the carers. This happens on every occasion that we witness the arrival of the shorebirds to the places that are restored each year, a positive joy. Maintenance of the various roost sites has become a wonderful opportunity to introduce people to shorebirds.

Stakeholders and funding bodies. At each stage of the project an initial effort of primary works was carried out by contractors and funded through various Government programs including the Australian Government’s Caring for Our Country, Envirofund and Threatened Species Recovery Fund.   The following have supported the works in some manner over the last twenty years; Twitchathon, Bird Interest Group Network (BIGNet), Birdlife Australia,  Conservation Volunteers Australia, the NSW Departments of Primary Industries and Fisheries, and Planning and Environment (and their predecessors), Hunter Bird Observers Club, Hunter Catchment Management Authority, Hunter Local Land Services, Hunter Regional Landcare Network, Kooragang Wetlands Rehabilitation Project, NSW National Parks & Wildlife Service, Newcastle Kayak Tours, Newcastle City Council, Newcastle Coal Infrastructure Group, NSW Government, Toolijooa, Trees In Newcastle, University of Newcastle.

The volunteer effort has been led by members of HBOC that make up the core team. Additional contributions have been made from other groups from time to time including: Better Earth Teams, Green Army, International Student Volunteers, TAFE students, Koora Gang, Intrepid Landcare, Worimi Green Team, Stockton Scouts, Raymond Terrace Scouts, Al Gazzali and Rigpa Buddists.

Contact information. For more information contact Tom Clarke thomas.clarke7@bigpond.com and project reports can be viewed on the HBOC website Rehabilitation Projects – Hunter Bird Observers Club (hboc.org.au).

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Posted in Assisted regeneration, Coastal & marine, Community involvement, Fauna & habitat, Integrating ecosystems & industries, Landscape pattern & design, Mangroves, Migratory shorebirds, Mudflats, New South Wales, Restoration & management theory, Saltmarsh, Techniques & methodology, Threatened species & communities, Urban ecosystems, Weed issues & solutions, Wetland

Holistic regenerative management on a grazing farm, Allendale, Boorowa is leading to more complex native pastures and increased biodiversity

Posted on 29 April 2023 by | Comments Off on Holistic regenerative management on a grazing farm, Allendale, Boorowa is leading to more complex native pastures and increased biodiversity

David Marsh

Figure 1. David Marsh among native grasses that naturally regenerated at Allendale (Photo T. McDonald).

Introduction:  When we purchased the 814 ha ‘Allendale” property in the wheat-sheep belt of the Southwest Slopes of NSW in 1966, almost all of the plants that had evolved here over millennia had disappeared although Europeans had only been here for 142 years. All that remained of the woody components were some scattered Yellow Box (Eucalyptus melliodora), Blakeley’s Red Gum (E. blakelyi) , a few White Box (E. albens), a few Apple Box (E. bridgesiana), and very few Hickory Wattle (Acacia implexa). The ground layer, which normally includes most of the biodiversity in grassy woodlands had almost completely disappeared.

During first 18 years (of the 52 years) managing our farm we took a conventional approach to farming, having a largely economic relationship with the land and applying all the latest agronomy to lift yields. In 1989 we began a shift towards a process of ‘recovery grazing’ using Alan Savory’s  Holistic Resource Management approach. This was motivated not only by our values of wanting to leave the local landscape in healthy condition but also by the fact that the conventional mixed farming model was driving our farm  into incrementally increasing debt. We realized that we were attempting to run a fixed enterprises in a variable climate of recurring drought and that wasn’t working.  Training in holistic management with a certified educator in 1999 gave me the confidence to take the process more seriously, as did my enrollment in a Grad Dip. of Sustainable Agriculture followed by a Masters degree in Sustainable Agriculture.

The basis of recovery grazing is to avoid preferential and repeated overgrazing of desirable perennials by using rotational grazing in many small paddocks (to avoid repeatedly grazing recovering plants) rather than set grazing in a few paddocks. This allows longer recovery times for the desirable native perennial grasses and avoids creating conditions best suited to annuals of less value to livestock.  The ecological and economic results of our efforts have been outstandingly positive.

Works undertaken: Our first objective was to get costs under control. Surprisingly, for us this meant discontinuing cropping. Despite intermittent large profits from cropping our analysis showed that it was not profitable overall due to the number of dry years, wet harvests and frosts. We also started managing livestock differently. We created more land divisions using conventional or electrical fencing and, in our case, piping water to each paddock rather than radiating paddocks around the dams. (A trial of the latter showed it would cause too much erosion over time.) The troughs, energiser and solar panels are moved with the cattle, each move taking less than an hour.  Fencing and water cost us $85/ha at the time and was completed in 5 years, which compared favourably to spending $70K a year on fertilisers and pesticides during our cropping phase.  Instead of 12 mobs of cattle and 26 paddocks we now have 104 paddocks (and usually one mob of cattle), running them on an agistment basis that happens to suit us. Each paddock is only grazed for a total of about 10 days per year which gives time for not only existing pasture species to recover but for new species to recruit.

Most of our vegetation restoration approach relies on natural regeneration including both groundcovers and trees.  But we have planted quite a few scattered trees and have also sown some native grass seed – either hand broadcasting after collecting it from roadsides (or where it has recovered on the property) or after mechanized seeding of purchased batches from other farmers interested in the same process.  Cattle are also agents in seed dispersal as they spread it when grazing plants with ripe seed. A technique that we have used occasionally is to intentionally move the mob from a paddock with ripe seed (after they have had a big feed)  to a paddock that doesn’t have much of the species we wish to encourage. Effectively the cattle are harvesting and sowing the seed for us at no cost.

Figure 2. Increase in native grass presence at Allendale over time. (1999 -2020)

Results to date:

Woody vegetation. Tree cover on Allendale has increased from 3% cover in 1966, to over 20% in 2022 (through both tree planting and natural recruitment). Since 2010 – when it rained after a nine-year dry spell – the big remnant trees began to reproduce. The long recoveries from grazing allowed around 800 saplings (with temporary electric tape to protect them from being grazed for a few years), to survive and become trees. This is the first time any native trees have germinated and survived on Allendale in over 100 years.  Wattles (Acacia spp.) were originally direct seeded and are now recruiting.  This increase in woody vegetation and cycling provides the basis for a far more complex ecosystem on Allendale (with more insects, small reptiles, birds and a range of mammals) compared to recent previous decades.

Bird life. With these changes, a whole lot of other ecological shifts are also occurring at no cost. These days there are many thousands of quail (Coturnix sp.), finches (Neochmia spp.) and wrens (Malurus spp.) are present in increasing numbers. Dusky Wood Swallow (Artamus cyanopterus cyanopterus) and White-browed Wood Swallow (Artamus superciliosus ) come nearly every year and breed here; the Rufous Songlark (Cincloramphus mathewsi ), a ground nesting bird that we seldom saw previously, is now frequently observed. Various raptors are constantly here; the Black Shouldered Kite (Elanus axillaris), Nankeen Kestrel (Falco cenchroides), Wedge-tailed Eagle (Aquila audax), Brown Falcon (Falco berigora), Swamp Harrier (Circus approximans), Spotted Harrier (Circus assimilis) and Peregrine Falcon (Falco peregrinus) are frequent visitors. To date there have been 128 species of birds identified on the property, and we have observed informally that many of these species (and their abundance) have increased in recent years.

Grasses. Cibolabs analyses have shown that our ground cover levels have been at 100% for many years now and there have been particular increases in native grasses (Fig. 1).  We mapped the native grasses on the property in 1999 and found them present in only 1 ha out of 814 ha and confined to rocky outcrops that could not be ploughed and in a few fence corners. Repeat mapping in 2004/5 showed native grasses covered a larger area (~86ha) – with further increases mapped in 2010 (189ha) and 2020 (440ha) (Figs 2-5).  Indeed, representatives of the warm season perennials that evolved here can now be found in most if not all our paddocks even though too scattered to map.

The grass species include wallaby grasses (Rytidosperma spp.), Common Wheat Grass (Elymus scaber), spear and corkscrew grasses (Austrostipa spp.), Umbrella Grass (Chloris truncata), Kangaroo Grass, (Themeda triandra), Weeping Grass (Microlaena stipoides), Box Grass (Paspalidium distans), Arm Grass (Brachiaria milliformis), Queensland Blue Grass, (Dicanthium sericeum), Red Grass, (Bothriocloa macra), Cotton Panic (Digitaria brownii) and Wild Sorghum (Sorghum leiocladum). All these species have increased markedly in recent years, with the big stand-outs being Arm Grass, Box Grass, the wallaby grasses and Umbrella Grass (See Appendix 1).

While we believe the grasses would have gradually increased over time without sowing, we have accelerated the process by sowing some species in small quantities using a disc seeder in some sites, but mainly broadcasting seed by hand from a quad bike (Figs. 3 and 4 0a.nd Appendix 1).  Seeds were also dispersed by the cattle.

Figure 3. Locations of seed sowing treatments over time at Allendale.

Figure 4 Locations of seed sowing treatments over time at Allendale.

Figure 5. Native grass presence in all Allendale paddocks (with and without sowing) by 2020

Non-natives.  Achieving change has been more difficult in the paddocks where we had previously introduced exotic seed mixes including Cocksfoot (Dactylis glomerata) and Phalaris (Phalaris aquatica). These two perennial exotic grasses are highly dominant and can temporarily competitively exclude native grasses (even if the latter may still be present) –  particularly in wet seasons.  Experience suggests that this may  explain why native grass sowings in recent high rainfall years have not yet shown results (Figs 4-5).  These species are still valuable for grazing, however, as is Paspalum (Paspalum dilatatum) – which has increased – and Plantain/Ribwort (Plantago lanceolata) which is considered beneficial to the quality of the pasture.

In general, however, managing ground cover to reduce bare ground has helped managed disturbance-adapted invasive weeds such as Illyrian Thistle (Onopordum illyricum), Patterson’s Curse (Echium plantagineum), Capeweed (Arctotheca calendula) and Amsinckia (Amsinckia spp.); all of which now occur only occasionally. Importantly, we previously had an annual spraying program for some of the problematic annuals but we have not done that for 22 years;  managing ground cover to reduce bare ground goes a very long way to manage the populations of disturbance-adapted species. Any small patches of high-risk weeds (e.g. Rubus sp. and Rosa sp.) have proven manageable by mattocking out.

Lessons learned: Our goal is to live in a landscape increasing in biodiversity and to meet our economic goals. Over 30 years we were expending large amounts of money on contractors while rolling the dice against the weather, with little time for holidays.  We have found that we now usually have perennial native grasses dominating in summer and that this avoids the previous boom and bust cycle. The recovery grazing management (probably combined with reduced nutrient loads) has now resulted in more diverse native perennial pastures and avoids the cost of resowing. This allows time for habitat to develop to increase native fauna and allows us to produce time for recreation.

The benefits we have seen however, required a changed mindset.  It is quite hard for farmers to avoid intervening.  We had lots of weeds for many years because our previous management had pushed succession all over the farm back to an early state due to the creation of bare ground, even though we had sown perennials. A more mature succession took 3-5 years after ceasing sowing, weed control and overgrazing, so it did not occur overnight.  Importantly, all this required quite a philosophic conversion. Quite a lot of the farmers going down this track show a shift in attitude, characterized by patience and a greater willingness to take responsibility for land outcomes.  Such a changed mindset is not yet being entertained by the number of farmers needed to stop the slow but inexorable decline of biodiversity on farmland.   Yet more farmers are thinking about it now compared to in the last 20 years, which is an encouraging sign.

Acknowledgements: Thanks goes to my family (Mary Marsh, Skye Rush, Hugh Marsh and Alice Needham) and to my farming colleagues that have also been going on this journey (Charles Massy, Colin Seis, Martin Royds and Scott Hickman) .

Contact: David Marsh, Allendale, Boorowa NSW, Australia. Email: marsh.allendale1@gmail.com

Appendix 1. The main grass species, treatments and results at Allendale over approximately two decades.

Species Intervention Results
Wallaby grasses (Rytidosperma spp.) Very little seed has been scattered of one variety only Six varieties are now present and appeared within 3-5 years. All are spreading.
Box grass

(Paspalidum distans )

 Included in the total of  ~8×40 kg bags of seed purchased from another farmer, Colin Seis, over the years) and hand dribbled in rows about 20m apart from the quad bike.  Also included in the ‘Seis mix’ disc-seeded into paddocks totalling 150ha. In 1999 only found in one or two small patches but now it is every across the property
Umbrella Grass

(Chloris truncata)

 Included in the above-described ‘Seis mix’ hand dribbled and disc-seeded Was present in 1999 but now it is widespread as the seed heads are like umbrellas and tumble
Arm Grass  – Brachiaria milliformis Included in the above-described ‘Seis mix’ hand dribbled and disc-seeded Was absent when first came here.  Now it is widespread and increasing all the time.

 
Kangaroo grass – (Themeda   triandra) A total of half a wool pack from nearby roadside has been dispersed by hand from a quad bike over the ~15 years (split over ~four occasions). Was absent when first came here but was present on the roadside. It is not spreading rapidly but is starting to come back.

 
Corkscrew and tall Stipa

(Austrostipa spp.)

 

 Pre-existed and not collected. Some was present in uncropped areas. As a pioneer it can now be seasonally abundant.
Red grass (Bothriochloa macra) A little pre-existed was original present  but some is in the ‘Seis mix’ hand dribbled and disc-seeded Some was present in uncropped areas. It is now increasing although quite slowly.
Weeping grass (Microlaena stipoides) Some seed was included in grass culms harvested from a nearby property and ‘blown’ out onto some Allendale paddocks by Owen Whittaker. Some was present in uncropped areas.  It is gradually increasing.
Common Wheat Grass (Elymus scaber)

 

 No seed was sown but have collected from Allendale paddocks and distributed by hand a from quad bike. Some was present in 1999 but it is now spreading extensively. The species is relatively insignificant but has a place in a pasture.

 

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Posted in agricultural lands, Assisted regeneration, Cultural & socio-economic issues & solutions, Ecosystem services, Fauna & habitat, Grassland/grassy understorey, Integrating ecosystems & industries, New South Wales, Reintroduction, Restoration & management theory, Techniques & methodology, Weed issues & solutions

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Post-fire assisted regeneration at Rutidosis Ridge, Scottsdale Reserve, Bredbo NSW

Posted on 2 May 2021 by | Comments Off on Post-fire assisted regeneration at Rutidosis Ridge, Scottsdale Reserve, Bredbo NSW

 

Figure 1. Undamaged grassy woodland reference site occurring at high elevation at Scottsdale (Photo: Brett Howland)

Introduction. Scottsdale Reserve is a 1,328-hectare private conservation reserve, near Bredbo NSW, owned and managed by Bush Heritage Australia. For over 100 years prior to purchase in 2006 the property was utilised for grazing and cropping. While most of the higher elevation areas of the property remained intact and offered the basis for improving landscape connectivity for wildlife, the agricultural land use had resulted in conversion of the flats and lower slopes of the property to largely exotic pasture species and accompanying weed.

This case study focuses on one approx 10 ha Apple Box (Eucalyptus bridgesiana) / Snow Gum, (Eucalyptus pauciflora) grassy woodland ridge within the property – named ‘Rutidosis Ridge’ because it is the location of a small population of the Endangered plant species Button Wrinklewort (Rutidosis leptorhynchoides). Set-grazing by sheep as well as some cropping had left the site nearly wholly dominated by the landscape-transforming exotic pasture grasses African Love Grass (Eragrostis curvula) and Serrated Tussock (Nasella tricotoma). Some scattered copses of eucalypts and some herbaceous natives remained, however, suggesting that the site might have some native regeneration potential, but the number and abundance of natives on the site appeared very low and the site was very dissimilar to a nearby healthy reference site (Fig. 1).

Works undertaken. Around a decade after land purchase and the discontinuation of grazing and cropping, Rutidosis Ridge was aerially sprayed during winter with flupropinate herbicide at a low dilution (1L / ha) known to be effective on some strains of African Love Grass and Serrated Tussock without killing native grasses and forbs. While the African Love Grass and Serrated Tussock had died by the following spring as a result of this soil-active herbicide, no substantial native regeneration was observed due to the persistence of the thick thatch of dead African Love Grass (Fig 2).

  • Figure 2.  Typical site showing sprayed African Love Grass thatch even many years after aerial spraying. (Photo T. McDonald )
  • Figure 3.  Intense wildfire that passed through Bredbo, NSW in early February. (Photo” New York Times)

An intense wildfire passed through the property on 2nd February 2020 (Fig. 3). This largely consumed the thatch, exposing stony topsoils and providing opportunities for regeneration of both natives and weeds that were stored in the soil seed bank.  Anticipating the need for post-fire spot-spray follow-up after the fire to avoid any native regeneration being overwhelmed by weed, Bush Heritage Australia (BHA) collaborated on a program of regular selective treatment of weed with the restoration organisation the Australian Association of Bush Regenerators (AABR). Personnel involved both contractors and volunteers skilled in recognising natives and weeds at seedling stage capable of spot-spraying with negligible off-target damage (Fig 4).  

Because the fire had removed African Love Grass thatch and cued germination of natives and weeds, the aim was to treat all weed prior to its seeding.  This allowed the managers to (a) take advantage of the fire’s flushing out the weed soil seed bank and avoid its further recharge and (b) retain maximum open spaces for further natives to emerge and colonise. 

During the year after the fire (March 2020-April 2021), the ~10ha site had been subjected to approx. 600 person hours of spot spraying, mainly undertaken by experienced bush regenerators. This commenced in March 2000 and continued at least fortnightly during the growing season.

Figure 4. Location of comprehensively spot-sprayed areas and target-weeded areas at Rutidosis Ridge. An opportunity exists to compare differences in richness and cover of natives and weed between the two treatments, ensuring comparisons are confined to within-comparable condition classes.

What we found by 1 year of treatments.  Post-fire observations in  March 2020 revealed Snow Gum resprouting from lignotubers and roots and Apple Box and Candlebark (Eucalyptus rubida) resprouting epicormically.  A wide suite of native grasses and forbs were starting to resprout or germinate alongside diverse herbaceous weeds. Within the first 12 months of regular spot-spraying, the cover and seed production of approx. 30 weed species was very substantially reduced.  Combined with fairly evenly distributed rainfall in the follow 12 months this reduction in weed allowed ongoing increases in native species cover and diversity per unit area, with seed production likely by most native species.  There was negligible off-target damage from the spray treatments. In December 2020 over 50 native herbaceous and sub-shrub species (including at least 11 Asteraceae, 9 Poaceae, 4 Fabaceae and 2 Liliaceae) were recorded within the work zones, with cover of natives very high in the higher condition zones, but plentiful bare ground remaining in the lower condition zones (Fig. 5).  

Figure 5.  Top:  Directly after wildfire showing black stubs of African Love Grass; Middle: Volunteers spot-spraying during the growing season, and Bottom: same site after 12 months but when native grasses were curing off after seeding. (Photos T. McDonald)

Predominant weed species included recovery African Love Grass, Viper’s Bugloss (Echium vulgare), St John’s Wort (Hypericum perforatum), Yellow Catsear (Hypochoeris radicata), Common Plantain (Plantago major), a range of thistles and around 20 other weed species.

Predominant natives included speargrasses (Austrostipa spp.), Redleg Grass (Bothriochloa macrantha), Kangaroo Grass (Themeda triandra), Native Panic (Panicum effusum), Common Raspwort (Gonocarpus teucrioides), Bindweed (Convolvulus erubescens), bluebells (Wahlenbergia spp.), Common Everlasting (Chrysocephalum apiculatum), fuzzweeds (Vitadennia spp.), Bear’s Ear (Cymbonotus lawsonianus), Creamy Candles (Stackhousia monogyna), Yellow Pimelea (Pimelea curviflora subsp. fusiformis) and Native St John’s Wort (Hypericum gramineum).  Species of higher conservation interest that regenerated included Blue Devil (Eryngium ovinum) and Threatened species that regenerated included Silky Swainson’s Pea (Swainsona sericea) and Button Wrinklewort. (Some of these species are pictured in Fig. 6).

Figure 6. Some of the forbs that flowered on Rutidosis Ridge during the growing season – including the Endangered Button Wrinklework (centre) and Vulnerable Silky Swainson’s Pea.(bottom left). (Photos various.)

Gradient of condition improving over time. As expected, the sites showed a gradient of condition (Fig. 7), with highest natural regeneration capacity retained in the tree clusters and stony crest, perhaps due to these less likely to be less favoured by sheep. (The tree clusters appear not to have been used as sheep camps). By March 2020, 1 year after work commenced, all sites were on a trajectory to move to the next higher condition class, assuming successful Winter 2021 aerial spray re-treatment of African Love Grass.  (Note that, while the pre-fire flupropinate treatment would normally have a residual effect for a few years and thus preventing germnation of this species, massive germination did occur of African Love Grass in many areas, which we speculate was either due to suitable post-fire germination conditions being delayed by the presence of dead grass thatch or to a possible denaturing of the chemical by the fire.)  

Figure 7. Condition classes in the Rutidosis Zones A-E revealed during the first few months of treatment. By the end of the growing season and after regular follow up spot-spraying it was clear that all zones comprehensively treated were improving in their native: weed cover ratio except for an increasing cover of African Love Grass, the treatment of which was deferred until a second aerial spray scheduled for winter 2021. (Map: T. McDonald)

Acknowledgements: This project would not have been possible without the help of BHA and AABR volunteers.

Contact: Tein McDonald and Phil Palmer, Scottsdale Tel: +61 (0) 447 860 613; Email: <teinm@ozemail.com.au and phil.palmer@bushheritage.org.au

 

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Posted in Assisted regeneration, Bush regeneration, Community involvement, Fire Ecology & Management, Grassland/grassy understorey, New South Wales, Restoration & management theory, Sclerophyll communities, Techniques & methodology, Threatened species & communities, Uncategorized, Weed issues & solutions

Crowdy Bay National Park, NSW – Assisted regeneration of a littoral rainforest patch post 2019-20 summer wildfire

Posted on 5 April 2021 by | Comments Off on Crowdy Bay National Park, NSW – Assisted regeneration of a littoral rainforest patch post 2019-20 summer wildfire

Figure 1. Volunteers at the initial working bee in the burnt littoral rainforest.

Introduction. Crowdy Bay National Park is located on the NSW Mid-north coast and comprises coastal landscapes, some of which have were sand mined prior to the area’s acquisition for conservation in the 1970s. Littoral rainforest remnant and regrowth patches occur within the Park and are listed at State level and as Endangered Ecological Community and at national level as a Threatened Ecological Community. The rainforest community type forms in the dune swales, protected by Coast Banksia (Banksia integrifolia) and is dominated over time by Tuckeroo ( Cupaniopsis anacardioides) and Beach Alectryon (Alectryon coriaceus), with other rainforest co-dominants and associated shrubs, vines and groundcovers.

For over four decades,  a regeneration program has been carried out in the park by volunteers working through the National Parks Association (NPA), Mid North Coast Branch. This short summary refers to the condition of one floristically diverse littoral rainforest patch at Kylie’s Beach, half of which was burnt in a spot-wildfire in late 2019 and in which weed managment works commenced 2 years prior to the wildfire due to pre-existing weed issues (Fig 1).

The wildfire and early recovery. The wildfire burnt all the banksias on the foredune crest that were providing wind protection for the littoral rainforest, as well as 1ha of the littoral rainforest. It left the ground layer beneath both areas largely bare. In the areas burnt, all trees appeared dead. With rainfall occurring soon after the fire, post-fire coppicing of rainforest trees and Banksia commenced; with germination of native seedlings occurring with the arrival of heavy rains in December 2020 -January 2021. By mid-autumn 2020 the northern foredune section was thickly covered with colonising Blady Grass (Imperata cylindrica) that provided cover for other successional natives (Fig 2) .

Weed recovery, however, was very rapid. As early as May 2020, the site was a sea of annuals, with abundant Lantana (Lantana camara), Coastal Morning Glory (Ipomoea cairica), Cape Gooseberry (Physalis peruviana), Crofton Weed (Ageratina adenophora) and scatterings of Cape Ivy (Senecio mikanioides) and Tobacco Bush (Solanum mauritianum). Volunteers were at a loss to see how the site could be helped to regenerate. Not having previously worked in a burnt rainforest, the first though was to take out all the weeds. Under the guidance of retired regenerator Tom Clarke from the Australian Association of Bush Regenerators (AABR) however, a different approach was taken.

Figure 2. Blady Grass has covered much of the floor.

Works undertaken. Commencing in May 2020 Sue Baker from NPA and Tom Clarke from AABR conducted monthly working bees to strategically remove weeds. The approach was to  regard the weeds as the new canopy cover and primary colonisers, providing invaluable shade and moisture retention for the regenerating rainforest species. It was agreed that the main initial objective was to see the re-establishment of a canopy, however low, to protect the ground moisture levels and any recovering herb layer. At this point any woody weeds were considered allies in that they were resprouting along with many native pioneer species. Treatment of woody weeds was selective and dependent upon direct competition with native plants. Instead, treatment of weed vines and creepers was targeted, with removal of Morning Glory and Cape Ivy a priority, at least to the edge of the burnt zone.

Subsequently, apart from preventing the spread of Cape Ivy and removing dense infestations of fruiting Cape Gooseberry, the method was to remove weeds only where they were competing with native seedlings with as much removal of their fruits and seeds as possible, followed by thinning out later where helpful. By January 2021, native ground cover had recovered sufficiently to remove the annuals, some of which were 2m high. Over time, the selective treatment of woody weeds has continued as more and more native regen appeared. By taking this approach we have left nature largely to do its own thing with minimal detrimental impact from weeding.

In addition, we have taken the view that the wildfire was not soley a negative; it has also provided an opportunity to address some of the long-standing weed issues in the broader area of Kylie’s Beach including that of Glory Lily (Gloriosa superba) and Golden Wreath Wattle (Acacia saligna) which the fire stimulated to germinate from the soil seed bank in their thousands.

As well as the weed management work, over a kilogram of native seed was broadcast in mid-summer 2020 in the hope it might improve recovery of the ecosystem.

Volunteer visits. After a site inspection tour on 14th May 2020 there have been at least 17 visits to Crowdy Bay National Park where regeneration works has been carried out, not only in the littoral rainforest, but also in the broader Kylie’s beach area. These occurred in May (1 visit), July (3 visits), August (4 visits involving 12 volunteers), September (2 visits), October (4 visits), November (1 visit) and lately in January 2021 (2 visits).

Figure 3. Tuckeroo coppicing from the burnt stump.

Figure 4. Lillypilly coppicing.

Results to date.  The site has demonstrated itself to have high levels of native resilience, having been in relatively healthy condition apart from per-existing weed infestations. High levels of rain in the 2020-21 summer has promoted extensive and vigorous growth. At February 2021, the forest floor was a carpet of native vegetation and some areas knee-high in dense native grasses. Less care in selecting woody weeds for treatment is now required.

Much of the regeneration is from germinating seeds but some has been from re-sprouting rootstocks, resprouting stems or coppicing from the bases of trees, including rainforest trees (Figs 3 and 4) although some large trees are dead  (See Table 1). With the assisted regeneration work (i.e. strategic weed removal post-fire) the site is quickly shifting from a predominantly weed-dominated post-fire succession to one dominated by native plants.

There is no evidence that the sown seed has yet contributed to the regeneration at this stage.  Native regeneration was occurring across the area prior to the date when germination of sown seed would be expected and it is now clear that additional seed was not required.

Plans for ongoing management.  The continued wet and humid conditions in summer 2021 have provided highly favorable conditions for regeneration. During 2021 the volunteers will try to keep up with the work at Kylie’s Beach through regular bush regeneration camp outs (as organised for many years, except 2020 which was cancelled due to COVID-19 restrictions). Work plans for the next camp-out have been scheduled to include the Kylie’s Beach littoral rainforest site and will include follow-up treatment of vines and Crofton Weed. Full recovery is likely to take years as the recovery process moves at its own pace.

Two major issues remain – dense ground and canopy cover of coastal morning glory in the area will need meticulous treatment. Also an entire drainage line on the steep, rocky cliff face behind the dune is densely infested with Crofton Weed that must be left in place to stabilize the slope until sufficient native cover takes hold. Volunteers were able to remove flowers from the Crofton Weed for a certain distance up the slope. Contractors will be needed in 2021 to deal with the upper slope.

Acknowledgements: We thank the organisation and leadership of NPA group.  The fact that this was already in place prior to the fire, was a key to the success of the work to date. This group has an outstanding history and connection with many sites in the Park over many years. The linking of AABR to the project provided additional support in project design and facilitating additional volunteer from the ABBR network for the post-fire restoration side of the program.

Contacts:  Tom Clarke AABR 0418411785 and Sue Baker (NPA MNC branch)

Table 1. Kylie’s Beach Littoral Rainforest Post Fire Restoration  – responses of native and exotic species (Exotics marked with an asterisk)

Scientific name Common name Response of the species at this site Notes
Grasses
Imperata cylindrica Blady Grass Resprouted Dominating burnt floor devoid of canopy
Oplismenus aemulus Basket Grass Resprouted and germinated Near edge of existing canopy
Ehrharta erecta* Panic Veldtgrass Germinated Hillside on open ground near crofton weed
Eriochloa procera Spring Grass Germinated Near edge of existing canopy
Scramblers and Climbers
Marsdenia flavescens Hairy Milk Vine Resprouted and germinated At edge of existing canopy
Senecio mikanioides* Cape Ivy Resprouted Remnants creeping through grasses, has been heavily targeted.
Ipomoea cairica* Mile-a-minute Resprouted and germinated Existing condition taking advantage, targeted for weeding
Desmodium sp. (varians?) Desmodium Germinated Carpeting over slope to dune swale
Glycine sp. (tabacina?) Love Creeper Germinated Carpeting over slope to dune swale
Sarcopetalum harveyanum Pearl Vine Resprouted and germinated Near edge of existing canopy.
Stephania japonica Snake Vine Resprouted and germinated Near edge of existing canopy or large remnant structures
Dioscorea transversa Native Yam Resprouted Near edge of existing canopy or large remnant structures
Passiflora edulis* Blue Passion Flower Resprouted and germinated Single isolated plant. Previously overlooked?
Rubus parvifolius Native Raspberry Resprouted and germinated Creeping through rank grasses
Cayratia clematidea Slender Grape Resprouted and germinated Creeping through rank grasses
Cissus antarctica Kangaroo Grape Resprouted Mostly at edge of existing canopy.
Tetrastigma nitens Three-leaved Water Vine Resprouted Near edge of existing canopy
Flagellaria indica Whip Vine Resprouted Isolated individuals searching for structure
Geitonoplesium cymosum Scrambling Lily Resprouted Creeping through rank grasses
Smilax australis Austral Sarspariila Resprouted Moving into grass floor plus climbing burnt structures.
Ground Covers and Herbs
Hydrocotle bonariensis* Pennywort Resprouted Associated with commelina in low swale
Commelina cyanea Scurvy Weed Resprouted Feature of low swale within open floor area; also underneath grasses.
Melanthera biflora Melanthera Resprouted Carpeting top of rise from dune swale
Tufted Plants
Crinum pedunculatum Swamp Lily Resprouted Seaward edge to dune swale
Dianella congesta Coastal Flax Lily
Lomandra longifolia Mat Rush Resprouted and germinated Isolated individuals, seedlings and survivors
Ficinia nodosa Knobby Club-sedge Resprouted Seaward side pushing up from dune swale below
Cyperus sp. (sanguinolentus?) Sedge Resprouted Associated with commelina etc in swale near False Bracken
Alocasia brisbanensis Cunjevoi Resprouted Scattered near edge of existing canopy or structures.
Ferns
Doodia aspera Rasp Fern Resprouted Mostly near edges of existing canopy
Pellaea falcata Sickle Fern Resprouted Mostly with grass at edge of existing canopy
Calochlaena dubia False Bracken Fern Resprouted Dense patches on floor adjacent to Blady Grass
Dicksonia antarctica Treefern Resprouted Unaffected individuals near edges
Shrubs
Acacia longifolia (var. sophorae?) Golden Wattle Germinated Seedling growth mostly seaward edge of floor.
Breynia oblongifolia Coffee Bush Germinated Isolated individuals from seedlings
Banksia integrifolia Coastal Banksia Resprouted and germinated Coppicing from burnt stumps plus seedlings
Physalis peruviana* Cape Gooseberry Rampant pioneer exotic targeted for weeding
Solanum nigrum* Blackberry Nightshade Germinated Rampant pioneer exotic targeted for weeding
Lantana camara* Lantana Resprouted Rampant pioneer exotic targeted for weeding
Poyscias elegans Celerywood Germinated Scattered seedlings
Trema tomentosa var. viridis Native Peach Germinated Pioneer from seedlings; competing well
Conyza sumatrensis* Tall Fleabane Germinated Rampant pioneer exotic targeted for weeding
Notelea venosa? Mock Olive Resprouted Coppicing from burnt stump.
Bidens Pilosa* Cobbler’s Pegs Germinated Rampant pioneer exotic targeted for weeding
Phytolacca octandra* Inkweed Germinated Isolated patches
Ageratina Adenophora* Crofton Weed Resprouted and germinated?? Isolated patches on floor plus large, dense infestation covering hillside soak
Chrysanthemoides monilifera* Bitou Bush Resprouted and germinated Isolated individual plants
Trees
Cupaniopsis anacardioides Tuckeroo Resprouted and germinated Coppicing from burnt stumps plus seedlings
Wilkiea huegeliana Wilkiea Resprouted Coppicing from burnt stumps
Homalanthus populifolius Bleeding Heart Germinated Pioneer from seedlings; competing well
Alectryon coriaceus Beach Tamarind Resprouted Coppicing from burnt stumps.
Solanum mauritianum* Tree Tobacco Germinated Pioneer exotic targeted for weeding
Ficus rubiginosa Port Jackson Fig Resprouted Coppicing from burnt stumps
Laurel type Coppicing from burnt stumps
Synoum glandulosum Scentless Rosewood Resprouted Coppicing from burnt stumps

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Posted in Assisted regeneration, Bush regeneration, Coastal & marine, Community involvement, Fire Ecology & Management, New South Wales, Rainforest, Restoration & management theory, Techniques & methodology, Weed issues & solutions

The Role of Swamps in Drought: Popes Glen Creek, Blackheath

Posted on 4 October 2020 by | Comments Off on The Role of Swamps in Drought: Popes Glen Creek, Blackheath

Alan Lane

Introduction

The important role of swamps in water storage and as regulators of stream flow has been well documented (10.1016/j.geomorph.2018.03.004). Previous EMR project summary reports on Popes Glen Creek, Blackheath, have described the establishment of a swamp on the former highly degraded and weed-infested silt plug at the headwaters of the creek.  (See links at end of this summary.)  That 18-year long project has been documented in “The Full Story”, https://dl.bookfunnel.com/ebgais2pxn and an 8-minute summary video can be viewed at https://www.youtube.com/watch?v=610sas330EQ

The recent severe drought in New South Wales provided the opportunity to monitor the water table in this swamp in the absence of rain and compare the impact on the swamp vegetation with that on more elevated and drier slopes nearby.

How we measured the water table. Six piezometers were installed at the start of this rehabilitation project, located about 50 m apart and midway between the edges of the long, rectangular silt plug. These went down to the bedrock, at depths of between 113 and 152 cm and were used to monitor water table depth and also for sampling water quality and stygofauna.

What we found. During periods of normal or above average rainfall (e.g. September 2019), the water table at each of these bore holes was typically at the depth below soil surface shown in Table 1.

Levels fell almost to bedrock during the drought (Oct 2019 – Dec 2019), before recovering after rains in January and February 2020 (Tables 1, 2). 

Table 1. Water table depths during normal and below-average rainfall periods.

Bore hole number
Depth below surface (cm) 1 2 3 4 5 6
Normal rainfall period (Sept 2019) 31 2 7 11 23 9
After drought period (Dec 2019) 103 106 121 103 – 123
After recovering rainfall (Feb 2020) 29 0 12 21 – 13

Table 2.  Rainfall, October 2019 – February 2020.

Month Rainfall (mm)1 5-year average (mm)2 % of average
September 2019 81.4 53.6 151.6
October 2019 23.8 76.7 31.0
November 2019 26.4 82.2 32.1
December 2019 0.4 69.5 0.6
January 2020 99.2 127.9 77.6
February 2020 560.4 183.6 305
  1. From Bureau of Meteorology, Mount Boyce, NSW
  2. From willyweather.com.au, Mount Boyce, NSW

During this period of extreme drought, the vegetation on the slopes above the Popes Glen swamp manifested extreme water stress in a way never before seen (Figs. 1, 2). Many of these extensive expanses of Coral Fern (Glycaenia dicarpa), stands of Fishbone Water Fern (Blechnum nudum) and individual Black Tree Fern (Cyathea australis) plants have not recovered and now appear unlikely to do so.

Figure 1. Expanses of severely water-stressed Glycaenia dicarpa on slopes above the Popes Glen swamp.

Figure 2. Many of the Blechnum nudum and Cyathea australis on slopes above the swamp have failed to recover.

In marked contrast, the vegetation in the swamp area (Fen Sedge (Carex gaudichaudiana), Tassel Sedge (Carex fascicularis), Tall Spikerush (Eleocharis sphacelata) and Juncus sp.) remained lush and vigorous (Fig. 3), suggesting it was sustained by the supply of water retained in the substrate.

This supply was progressively depleted during the drought and the water table had fallen almost to bedrock before the rains in January (Tables 1, 2).

Figure 3. Vegetation in the Popes Glen swamp remained lush throughout the drought.

Implications. It seems inevitable that this water supply would have been completely exhausted had the 2019-2020 drought lasted longer. Temperate Highland Peat Swamps on Sandstone (THPSS), including the Popes Glen swamp, appear threatened by the even more prolonged droughts anticipated as climate disruptions due to global heating become more marked.

Acknowledgements. This work was supported by Blue Mountains City Council and funding from the Environmental Trust of NSW.

Contact. Alan Lane alanlane388@gmail.com

See also EMR Project Summaries:

 

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Posted in Bush regeneration, climate change, Community involvement, New South Wales, Restoration & management theory, Wetland

The rise of invasive ant eradications since the success of the Kakadu project  – UPDATE of EMR feature

Posted on 3 October 2019 by | Comments Off on The rise of invasive ant eradications since the success of the Kakadu project  – UPDATE of EMR feature

Benjamin D Hoffmann

[Update of EMR feature – Hoffmann,  Benjamin D and Simon O’Connor (2004) Eradication of two exotic ants from Kakadu National Park. Ecological Management & Restoration, 5:2, 98-105. https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2004.00182.x]

Key words. pest species management, invasive species, biosecurity

Figure 1. Kakadu staff in 2001 spreading formicide over a super-colony of African Big-headed Ant. This involved a team of people, aligned in a row, walking from one edge of the infested area to the other in parallel paths. (Photo courtesy of Simon O’Connor.)

Introduction. Invasive species management, especially eradications, has been at the forefront of biodiversity conservation gains over the past two decades. For example, over 1,200 invasive vertebrate eradications have been achieved on over 800 islands worldwide and the conservation benefits of such actions have been overwhelmingly positive and often dramatic. Efforts against invasive ants have also been particularly notable over the past two decades, with ants now being the second-most eradicated taxa globally having been eradicated from more than 150 locations, with the largest eradication covering 8300 ha. Two decades ago there were only 12 confirmed ant eradications using modern baits with a combined area totalling a mere 12 ha.

As reported in our original EMR feature, the last treatments against two invasive ants in Kakadu National Park, northern Australia: The African Big-headed Ant (Pheidole megacephala) and the Tropical Fire Ant, (Solenopsis geminata) were conducted in 2003; and the ants were declared eradicated two years later (Hoffmann & O’Connor 2004). At the time this was a globally significant eradication, and the positive outcome was a partial catalyst for the creation of many other relatively small exotic ant eradication attempts around Australia, including against Tropical Fire Ant on Melville island, and African Big-headed Ant on Lord Howe Island. Incidentally, the work coincided with the approximate timeframe of when two other highly invasive ant species were first detected in Australia: Red Imported Fire Ant (RIFA) (Solenopsis invicta), and Electric Ant (Wasmannia auropunctata), prompting the initiation of two massive national cost-shared eradication programs. One of these, the RIFA program, has become Australia’s second-most expensive eradication program at AUD $428 million as of at July 2019. Together, all of these actions put ants high on Australia’s biosecurity and environmental management radars, prompting the development of Australia’s Tramp Ant Threat Abatement Plan and yet even more eradication programs.

Figure 2. Ant bait being dispersed aerially by helicopter using an underslung spreader and side-mounted dispersers. (Photos Ben Hoffmann)

Further advancements in ant eradication programs.  As Australia’s eradication programs became more numerous and larger, it became apparent very quickly that the methodologies and technologies available were insufficient to achieve success in the increasingly challenging conditions being encountered. In response, over the next two decades, there has been an impressive range of advancements that significantly improved our capacity to manage and eradicate invasive ant incursions.

The biggest issue was that work needed to be conducted over such large or inaccessible areas that ground-based work (Fig 1) was not feasible. So, treatments quickly became aerial, using multiple helicopter-based delivery platforms (e.g. underslung buckets and side-mounted hoppers, Fig 2). Even so, there have been locations that are too remote, too small, or too difficult (ie cliffs) to treat using a helicopter. To meet this challenge, in just the last five years treatments have been conducted for the first time using drones, and there is a great focus now to improve the technology so that it becomes more cost effective and more autonomous (Fig 3). This is occurring at such a pace that just a few years ago drones could only operate for a few hours at most on battery power, and only carry a few kilograms. This year we will be using a drone with unlimited flying capacity (petrol driven) that can lift 70 kg per load.

Figure 3. The Fazer with side-mounted bait carriers that can lift up to 40kg of payload. This is soon to be superseded by a drone that can lift a 70k g payload. (Photo Ben Hoffmann)

Assessments for the presence of ants, either before or after treatments, was originally very time consuming, involving teams of people walking ground very slowly and often utilising thousands of attractive lures (Fig 4). At most, only small ant populations (about less than 20 ha) within good working environments (ie open landscapes) could be assessed using teams of people, and it took large amounts of time. It was found very quickly that detector dogs could be trained on the scent of each ant species, and a single dog could cover more than five times the area of a team of people in a single day with greater efficacy (Fig 5). There are now more than 20 detector dogs operating in Australia and New Zealand that have been trained on the scent of four ant species. But even a team of dogs cannot fully cover entire areas at the landscape-scale, such as is the case for the RIFA program, especially in areas with long grass or rugged terrain. One of the saving technologies for the RIFA program has been the development of a multi-spectral sensor and associated algorithms that can identify RIFA nests from imagery captured by remote sensing (Fig 6). This allows program staff to assess just a few identified point locations in a landscape rather than the entirety of landscapes, to determine RIFA presence or absence. The next envisaged step is the development of biosensors that can detect the odours of target ant species, just like detector dogs, and with time these will become small enough to be transported by small drones throughout landscapes to detect ants.

Figure 4. An area covered with hundreds of flags marking spoonfulls of catfood being used as lures to attract African big-headed ant to assess eradication success or failure. (Photo Ben Hoffmann)

Figure 5. An ant detector dog searching for the presence of Red imported fire ant. (Photo courtesy of The State of Queensland (Department of Agriculture and Fisheries 2010–2019))

Australia was caught particularly unprepared two decades ago when the two new exotic ant species were detected for the first time because there were no baits registered for their management in Australia, so legally there were no treatment products that could be used. Even with the implementation of Emergency Use Permits for some unregistered products, as well as the use of the few products that were available for other species, it was often found that individual products could not be used in particular circumstances, especially around water, within crops and on organic farms. Additionally, available baits often did not have high efficacy. With time many baits (comprised of combinations of an attractive food laced with an active constituent) have been formulated and tested providing a greater array of baits that can be used on any new incursion and in numerous settings. The most recent has been the development of hydrogel baits that essentially deliver a liquid product in a solid form.

Figure 6 a and b. Multi-spectral camera flown underneath a helicopter to detect Red imported fire ant nests. (Photos courtesy of The State of Queensland (Department of Agriculture and Fisheries) 2010–2019)

Among the numerous advances described already, possibly the greatest development is on the threshold of becoming a reality, in the form of genomic solutions for individual species. RNA interference, and gene-drive technology are rapidly being developed for a suite of economically important species, and ants are among the taxa that are highest on the priority list as targets for this research. At best, these genomic advances promise to provide species-specific solutions, thereby alleviating the current non-target issues of using toxicants.

Conclusion. Our ability to eradicate ants has improved dramatically over the past two decades, with technologies and methodologies available now that were as yet not thought of back when our work was conducted in Kakadu National Park. New programs are constantly arising, and forging ahead in increasingly challenging situations, and a great deal of effort is placed in information-sharing among programs. Simultaneously there is a sustained focus to improve biosecurity at Australia’s borders, as well as throughout our region to help prevent the need for eradications in the first place.

Contact. Ben Hoffmann, Principal Research Scientist, CSIRO Health & Biosecurity (PMB 44 Winnellie NT 0822 Australia; Tel: +61 8 89448432; Email: Ben.Hoffmann@csiro.au).

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Posted in EMR 20th anniversary updates, Fauna & habitat, Indigenous land & sea management, Monitoring, Northern Territory, Pest animal issues & solutions, Pest species, Restoration & management theory, Techniques & methodology

Butterfly population persists 10 years after emergency habitat restoration and translocation – UPDATE to EMR feature

Posted on 30 September 2019 by | Comments Off on Butterfly population persists 10 years after emergency habitat restoration and translocation – UPDATE to EMR feature

[Update to 2008 EMR feature  –  Raymond Mjadwesch and Simon Nally (2008) Emergency relocation of a Purple Copper Butterfly colony during roadworks: Successes and lessons learned. Ecological Management & Restoration,  9:2, 100-109.   https://doi.org/10.1111/j.1442-8903.2008.00400.x]

By Simon Nally and Raymond Mjadwesch

Fig 1.  The endangered Purple Copper Butterfly (Paralucia spinifera) (Photo Raymond Mjadwesch)

Key words:  Paralucia spinifera, Purple Copper Butterfly, reintroduction, invertebrate, threatened species.

Introduction: As reported in the original EMR feature, the unintended destruction of the habitat of a population of the endangered Purple Copper Butterfly (Paralucia spinifera, Fig 1) north of Lithgow, Australia in 2004, precipitated a bold, innovative, and rapid emergency program of habitat restoration and butterfly larvae translocation.

A stand of the butterfly’s larval host plants, Blackthorn (Bursaria spinosa subsp. lasiophylla), had been largely destroyed to enable road construction (Fig 2a). The butterflies had commenced emerging from their nearly nine-month-long pupation in the attendant ant’s (Anonychomyrma itinerans) underground nests to find an absence of host plants.

Construction work ceased immediately, and supplementary Blackthorn plants were planted throughout the area of predicted butterfly emergence. The Blackthorn were planted in their pots, to allow for later removal and replanting in the area where the habitat was being restored.  The Blackthorn were sugar-baited to attract the attendant ant as the ant was assumed to affect the male butterfly’s selection of home ranges, and ultimately, egg-laying on these larval host plants. Concurrently with the provision of Blackthorn for egg-laying, an adjoining degraded area of potential habitat was treated for infestations of woody weeds and growth of emergent Eucalyptus trees that excluded Blackthorn or blocked sunlight, precluding its suitability for occupation by the species.  Once weeds were controlled, Blackthorn was established in this area using tube-stock planting.

Attendant ants were enticed to all the Blackthorn introduced to the site, male butterflies established territories and were successful at attracting females with whom to mate, and these females laid eggs on the Blackthorn. The project partners were relieved at these initial results! However, as much of the site was to be permanently destroyed due to road construction, this temporarily reprieved population had to be translocated.

Over 12 nights, 1,260 of the facultatively nocturnal larvae were collected (along with any associated attendant ants) as they emerged to feed on Blackthorn leaves and translocated to the newly created habitat established on an adjacent restoration area (Fig 2b). Each translocated larva was monitored until it was attended by ants (again attracted to the recipient habitat using a sugar bait). Further monitoring continued to confirm continued growth of larvae until pupation was assumed to occur.

The duration of the emergency habitat restoration and translocation activities from first discovery of the habitat destruction to the assumed pupation of the translocated larvae in the newly established habitat (Fig 3) was less than five months.

After the autumn and winter pupation period, the project partners were delighted to find butterflies emerging, mating, and laying eggs on the remaining restored habitat, one year after the initial habitat destruction was first detected. Monitoring of larval numbers during 2005-2008, which involved systematic nocturnal inspection of all Blackthorn plants at the site, indicated that the population was secure and had grown after an initial reduction in calculated numbers in the first year after translocation.

Figure 2a. 2004 – The site as found showing the extent of habitat destruction (when the butterfly and habitat loss was initially detected). (Photo Raymond Mjadwesch)

Figure 2b. 2005 – Larvae from yellow-delineated area were translocated (after temporary introduction) into the blue-delineated area and bushland further right. (Photo Raymond Mjadwesch)

Monitoring update: In 2013 and 2015 monitoring reverted to an area search method, counting flying butterflies – a technique routinely used to indicate butterfly distribution / areas of activity at each of the other known populations. In 2015, ten years after the emergency translocation and habitat restoration, 48 butterflies were observed in the restored habitat, the second highest number recorded for this site.

Note that the results of monitoring counts can vary with date of survey relative to the flying period, time of day, and weather conditions on the day, and represent an indicator of presence and activity rather than a measure of absolute abundance. During some years multiple monitoring events occurred; in 2013 and 2015 there was only a single monitoring count.

There have been no further nocturnal larvae counts since the culmination of the project.

A 2019 site assessment identified the need for further woody weed maintenance works (which has been ongoing in the interim, funded by the LLS) to avoid potential degradation of the habitat quality due to competition with and shading of the host plant, Blackthorn.  Longer term maintenance of this site may require active management to ensure persistence of Blackthorn either through burning or mechanical damage to Blackthorn to promote re-sprouting from the rootstock and juvenile leaf production. Juvenile leaves lack the hairy indumentum present on the lower surfaces of intermediate and adult Blackthorn leaves, and have been observed to be preferentially skeletonized by early-instar larvae.

The 2019 site inspection also revealed that powerline easement works had resulted in weedicide spraying of eucalypt (Eucalyptus ssp.) saplings throughout the restored habitat, with Blackthorn plants and other native plant species affected.

Figure 3a – the site in 2005, after restoration works were complete, showing the initial flush of pioneer species after soil disturbance and restoration. (Photo Raymond Mjadwesch)

Figure 3b – the site in 2019 showing the final shrubby understory of sedges and shrubs (including scattered Blackthorn) typical of the locally native open forest community. (Photo Raymond Mjadwesch)

Lessons learned and future directions: Several factors contributed to the success of the habitat restoration and translocation program, some of which were of notable serendipity. It was extremely fortunate that the species was detected within the affected area (after the initial survey of the site had failed to detect habitat for the species); that Blackthorn tube-stock (upon which the restoration relied) was available; that an area considered likely to support Purple Copper Butterfly suitable for rehabilitation lay adjacent to the affected area; and that the timing of the damage in the annual lifecycle of the species allowed the partners to work with the opportunity to establish larval food plants  when it was required.

However, we believe that it was human factors that fundamentally combined to create the environment for success:

  • the commitment of the NSW Roads and Maritime Services (then the RTA) to immediately and fully support restoration works to ameliorate the damage and maximize the chances of the population surviving in the long term, including changing the design of the works to reduce the extent of permanent damage, and the funding of the restoration, translocation, and monitoring activities.
  • the project partners, including the authors, the RTA, NSW National Parks and Wildlife Service, Australian Trust for Conservation Volunteers, and Lithgow LandCare unified in collaboration, ceasing other activities to direct all necessary effort to maximize chances of success.
  • the quick, resourceful and bold action to trial and implement innovative techniques that were risky and speculative, such as luring attendant ants to planted Blackthorn using sugar, trial translocating attendant ants, and translocating larvae.
  • that there had been sufficient field observations to  predict the likely behavior of butterflies and larvae and to predict the likely response of the species’ habitat to management intervention.

We encourage restoration practitioners to immerse themselves in the environments they intend to manipulate, and ponder on the behavior, function, and interactions between each element of the ecosystem before them. When choosing to act – to intervene – to manipulate, do so sensitively to what you both know and feel that you have learned in the field, and act decisively, quickly, and boldly. Most importantly, corral a team of partners who believe in the endeavor and who fully commit their support to each other for a common restoration objective.

Endnote: In September 2019, an unplanned fire burnt much of the site. Given the monitoring data available for this site, further monitoring to study the effect of fire on the species and its habitat is being considered.

 Stakeholders and Funding bodies:   NSW Roads and Traffic Authority (now NSW Roads and Maritime), NSW National Parks and Wildlife Service (now NSW Office of Environment and Heritage), Australian Trust for Conservation Volunteers, Lithgow LandCare, Australian Government Department of Environment and Energy

Contact information: Simon Nally, 8 Gurney Place PAGE ACT, Australia, Tel: +61 407870234, Email: suseandsimon@bigpond.com. Ray Mjadwesch, Mjadwesch Environmental Service and Support, 26 Keppel Street, Bathurst, NSW 2795 Australia, Tel: +61 423949789, Email:  ray@mjadweschenvironmental.com.au

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Posted in Assisted regeneration, EMR 20th anniversary updates, Fauna & habitat, faunal reintroduction, Integrating ecosystems & industries, New South Wales, Restoration & management theory, Sclerophyll communities, Techniques & methodology, Threatened species & communities

Ku-ring-gai Flying-fox Reserve Habitat Restoration Project at Gordon, 2000 – 2019 UPDATE of EMR feature

Posted on 26 September 2019 by | Comments Off on Ku-ring-gai Flying-fox Reserve Habitat Restoration Project at Gordon, 2000 – 2019 UPDATE of EMR feature

Nancy Pallin

[Update to EMR feature –  Pallin, Nancy (2001) Ku-ring-gai Flying-fox Reserve Habitat restoration project, 15 years on.  Ecological Management & Restoration 1:1, 10-20. https://onlinelibrary.wiley.com/doi/10.1046/j.1442-8903.2000.00003.x]

Key words:         bush regeneration, community engagement, wallaby browsing, heat events, climate change

Figure 1. Habitat restoration areas at Ku-ring-gai Flying-fox Reserve within the urban area of Gordon, showing areas treated during the various phases of the project. Post-2000 works included follow up in all zones, the new acquisition area, the pile burn site, the ecological hot burn site and sites where vines have been targeted. (Map provided by Ku-ring-gai Council.)

Introduction. The aim of this habitat restoration project remains to provide self-perpetuating indigenous roosting habitat for Grey-headed Flying-fox (Pteropus poliocephalus) located at Ku-ring-gai Flying-fox Reserve in Gordon, NSW Australia (Fig 1).  The secondary aim was to retain the diversity of fauna and flora within the Flying-fox Reserve managed by Ku-ring-gai Council. Prior to works, weed vines and the activity of flying-foxes in the trees had damaged the canopy trees while dense weed beneath prevented germination and growth of replacement trees.  Without intervention the forest was unable to recover.  Natural regeneration was assisted by works carried out by Bushcare volunteers and Council’s contract bush regeneration team.  The work involved weed removal, pile burns and planting of additional canopy trees including Sydney Bluegum (Eucalyptus saligna), which was expected to cope better with the increased nutrients brought in by flying-foxes.

Figure 2. The changing extent of the Grey-headed Flying-fox camp from the start of the project, including updates since 2000. (Data provided by KBCS and Ku-ring-gai Council)

Significant changes have occurred for flying-foxes and in the Reserve in the last 20 years.

In 2001 Grey-headed Flying-fox was added to the threatened species lists, of both NSW and Commonwealth legislation, in the Vulnerable category.  Monthly monitoring of the number of flying-foxes occupying the Reserve  has continued monthly since 1994 and, along with mapping of the extent of the camp, is recorded on Ku-ring-gai Council’s Geographical Information System. Quarterly population estimates contribute to the National Monitoring Program to estimate the population of Grey-headed Flying-fox.  In terms of results of the monitoring, the trend in the fly-out counts at Gordon shows a slight decline.  Since the extreme weather event in 2010, more camps have formed in the Sydney basin in response to declining food resources.

In 2007, prompted by Ku-ring-gai Bat Conservation Society (KBCS), the size of the Reserve was increased by 4.3 ha by NSW Government acquisition and transfer to Council of privately owned bushland. The Voluntary Conservation Agreement that had previously established over the whole reserve in 1998 was then extended to cover the new area.   These conservation measures have avoided new development projecting into the valley.

From 2009 Grey-headed Flying-fox again shifted their camp northwards into a narrow gully between houses (Fig 2).  This led to human-wildlife conflict over noise and smell especially during the mating season. Council responded by updating the Reserve Management Plan to increase focus on the needs of adjoining residents.  Council removed and trimmed some trees which were very close to houses. In 2018 the NSW Government, through Local Governments, provided grants for home retrofitting such as double glazing, to help residents live more comfortably near flying-fox camps.

Heat stress has caused flying-fox deaths in the Reserve on five days since 2002. Deaths (358) recorded in 2013, almost all were juveniles of that year.  KBCS installed a weather station (Davis Instruments Vantage Pro Plus, connected through a Davis Vantage Connect 3G system) and data loggers to provide continuous recording of temperature and humidity within the camp and along Stoney Creek.  The station updates every 15 minutes and gives accurate information on conditions actually being experienced in the camp by the flying-foxes. The data is publicly available http://sydneybats.org.au/ku-ring-gai-flying-fox-reserve/weather-in-the-reserve/Following advice on the location and area of flying-fox roosting habitat and refuge areas on days of extremely high temperatures (Fig 3.) by specialist biologist Dr Peggy Eby, Council adopted the Ku-ring-gai Flying-fox Reserve 10 Year Management and Roosting Habitat Plan in 2018.  Restoration efforts are now focused on improving habitat along the lower valley slopes to encourage flying-foxes to move away from residential property and to increase their resilience to heat events which are predicted to increase with climate change.

Figure 3. Map showing the general distribution of flying-foxes during heat events, as well as the location of exclosures. (Map provided by Ku-ring-gai Council)

Further works undertaken.  By 2000 native ground covers and shrubs were replacing the weeds that had been removed by the regeneration teams and Bushcare volunteers.  However, from 2004, browsing by the Swamp Wallaby (Wallabia bicolor) was preventing growth of young trees and shrubs.  Bushcare volunteers, supported by KBCS and Council responded by building tree cages made from plastic-mesh and wooden stakes. Reinforcing-steel rods replaced wooden stakes in 2008.   From 2011, the Bushcare volunteers experimented with building wallaby exclosures, to allow patches of shrubs and groundcovers to recover between trees (Figs 3 and 4).  Nineteen wallaby exclosures have been built. These range in size from 7m2 to 225m2 with a total area of 846m2.   Wire fencing panels (Mallee Mesh Sapling Guard 1200 x 1500mm) replaced plastic mesh in 2018.  Silt fence is used on the lower 0.5m to prevent reptiles being trapped and horizontally to deter Brush Turkey (‎Alectura lathami) from digging under the fence.

The wallaby exclosures have also provided an opportunity to improve moisture retention at ground level to help protect the Grey-headed Flying-fox during heat events.  While weed is controlled in the exclosures south of Stoney Creek, those north of the creek retain Trad and privets, consistent with the 10 Year Management and Roosting Habitat Plan.

Madeira Vine (Anredera cordifolia) remained a threat to canopy trees along Stoney Creek for some years after 2000, despite early treatments.  The contract bush regen team employed sInce 2010 targeted 21 Madiera Vine incursions.

A very hot ecological burn was undertaken in 2017 by Council in order to stimulate germination of soil stored seed and regenerate the Plant Community Type (PCT) – Smooth-barked Apple-Turpentine-Blackbutt tall open forest on enriched sandstone slopes and gullies of the Sydney region (PCT 1841).  This area was subsequently fenced. The contract bush regeneration team was also employed for this work to maintain and monitor the regeneration in the eco-burn area (720 hours per year for both the fire and Madiera Vine combined).

Figure 4. Exclusion fence construction method. Pictured are Bushcare volunteers, Jill Green and Pierre Vignal. (Photo N Pallin).

Figure 5. Natural regeneration in 2018 in (unburnt) exclosure S-6 (including germination of Turpentines). (Photo N. Pallin)

Further results to date. The original canopy trees in Phase 1 and Phase 2 (1987 -1997) areas have recovered and canopy gaps are now mostly closed. Circumference at breast height measurements were taken for seven planted Sydney Blue gum trees.  These ranged from 710 to 1410mm with estimated canopy spread from 2 to 6m.  While original Turpentine (Syncarpia glomulifera) had circumferences from 1070 and 2350mm with canopy spread estimated between 5and 8m, those planted or naturally germinated now have circumference measurements between 420 and 980mm with canopy spread estimated from 1.5 to 3m.  A Red Ash (Alphitonia excelsa) which naturally germinated after initial clearing of weeds now has a circumference of 1250mm with a canopy spread of 5m.  Also three Pigeonberry Ash (Elaeocarpus kirtonii) have circumference from 265 to 405mm with small canopies of 1 to 2m as they are under the canopies of large, old Turpentines.  As predicted by Robin Buchanan in 1985 few Blackbutt (Eucalyptus pilularis) juveniles survived while the original large old trees have recovered and the Sydney Bluegum trees have thrived.

In the Phase 3 (1998 – 2000) area south of Stoney Creek the planted Sydney Blue Gum now have circumferences measuring between 368 and 743 (n7) with canopy spread between 2 and 6 m.  in this area the original large trees have girths between 1125 and 1770mm (n7) whereas trees which either germinated naturally or were planted now range from 130 to 678mm (n12).  These measurement samples show that it takes many decades for trees to reach their full size and be able to support a flying-fox camp.

Wallaby exclosures constructed since 2013 south of Stoney Creek contain both planted and regenerated species.  Eight tree species, 11 midstorey species, 27 understorey species and eight vines have naturally regenerated.  Turpentines grew slowly, reaching 1.5m in 4 years.  Blackbutts thrived initially but have since died. In exclosures north of the creek,  weeds including Large-leaved Privet,  Ligustrum lucidum,  Small-leaved privet,  L. sinense,  Lantana, Lantana camara,  and Trad, Tradescantia fluminensis) have been allow to persist and develop to maximise ground moisture levels for flying-foxes during heat events. Outside the exclosures, as wallabies have grazed and browsed natives, the forest has gradually lost its lower structural layers, a difference very evident in Fig 6.

Figure 6. Visible difference in density and height of ground cover north and south of Stoney creek. (Photo P. Vignal)

Coachwood (Ceratopetalum apetalum) were densely planted in a 3 x 15m exclosure under the canopies of mature Coachwood next to Stoney Creek in 2015. In 4 years they have reached 1.5m.  In this moist site native groundcovers are developing a dense, moist ground cover.

Madiera Vine, the highest-threat weed, is now largely confined to degraded edges of the reserve, where strategic consolidation is being implemented with a view to total eradication.

In the hot burn area, which was both fenced and weeded, recruitment has been outstanding. One 20 x 20m quadrat recorded 58 native species regenerating where previously 16 main weed species and only 6 native species were present above ground. A total of 20 saplings and 43 seedlings of canopy species including Eucalyptus spp., Turpentine and Coachwood were recorded in this quadrat where the treatment involved weed removal, burning and fencing  (S. Brown, Ku-ring-gai Council, July 2019, unpublished data).  Unfortunately, however, the timing and location of the burn did not take into account its impact on the flying-fox camp and there was some damage to existing canopy trees. It will be many years before the canopy trees, which are regenerating, will be strong enough to support flying-foxes.

Monitoring from the weather station and data loggers has shown that close to Stoney Creek on a hot day it is typically 2-3° C cooler, and 5-10% higher in humidity, than in the current camp area (pers. comm. Tim Pearson). During heat events the flying-foxes move to this cooler and moister zone, increasing their chances of survival.

Fauna observed other than flying-foxes includes a pair of Wedge-tail Eagle ( Aquila audax plus their juvenile, a nesting Grey Goshawk (Accipiter novaehollandiae) and a Pacific Baza (Aviceda subcristata).  Powerful Owl (Ninox strenua) individuals continue to use the valley. The presence of raptors and owls indicate that the ecosystem processes appear to be functional. Despite the decline of the shrub layer outside fenced areas, the same range of small bird species (as seen prior to 2000) are still seen including migrants such as Rufous Fantail ( Rhipidura rufifrons) which prefers dense, shady vegetation. The first sighting of a Noisy Pitta (Pitta versicolor) was in 2014.  Long-nosed Bandicoot (Perameles nasuta) individuals appear and disappear, while Swamp Wallaby remains plentiful.

Lessons learned and future directions. Climate change is an increasing threat to Pteropus species. On the advice of Dr Eby, Flying-fox Consultant, Council, KBCS and Bushcare Volunteers agreed to retain all vegetation including weeds such as Large-leaved Privet and Small-leaved Privet, patches of the shrub Ochna (Ochna serrulata) and Trad as a moist ground cover in the camp area and areas used by the flying-foxes during heat events.

Building cheap, lightweight fencing can be effective against wallaby impacts, provided it is regularly inspected and repaired after damage caused by falling branches. This style of fencing has the additional advantage of being removable and reusable.  It has been proposed that, to provide understory vegetation to fuel future burns in parts of the reserve away from the flying-fox camp, further such temporary fencing could be installed.

Ku-ring-gai Council has commenced a  program to install permanent monitoring points to annually record changes in the vegetation, consistent with the state-based  Biodiversity Assessment Method.

Stakeholders and Funding bodies. Members of KBCS make donations, volunteer for monthly flyout counts, Bushcare and present educational events with live flying-foxes. KBCS hosts the website www.sydneybats.org.au. Ku-ring-gai Council which is responsible for the Reserve has been active in improving management to benefit both residents and flying-foxes.  Ku-ring-gai Environmental Levy Grants to KBCS have contributed substantially to purchase of fencing materials and the weather station. http://www.kmc.nsw.gov.au/About_Ku-ring-gai/Land_and_surrounds/Local_wildlife/Native_species_profiles/Grey-headed_flying-fox

Thank you to Jacob Sife and Chelsea Hankin at Ku-ring-gai Council for preparing the maps and to volunteer Pierre Vignal for assistance with tree measurements, downloading data loggers and a photo.  Researcher,  Tim Pearson installed the weather station.

Contact information. Nancy Pallin, Management Committee member, Ku-ring-gai Bat Conservation Society Inc.  PO Box 607, Gordon 2072  Tel 61 418748109. Email:  pallinnancy@gmail.com

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Posted in Assisted regeneration, Bush regeneration, climate change, Community involvement, Cultural & socio-economic issues & solutions, Ecosystem services, EMR 20th anniversary updates, Fauna & habitat, Fire Ecology & Management, History, Monitoring, New South Wales, Planning, monitoring & assessment, Reserve management, Restoration & management theory, Sclerophyll communities, Techniques & methodology, Threatened species & communities, Urban ecosystems, Weed issues & solutions

Is revegetation in the Sheep Pen Creek area, Victoria, improving Grey-crowned Babbler habitat? – UPDATE of EMR feature

Posted on 24 September 2019 by | Comments Off on Is revegetation in the Sheep Pen Creek area, Victoria, improving Grey-crowned Babbler habitat? – UPDATE of EMR feature

Doug Robinson

[Update of EMR feature  – Robinson, Doug (2006) Is revegetation in the Sheep Pen Creek area, Victoria, improving Grey‐crowned Babbler habitat?  Ecological Management & Restoration, 7:2, 93-104.  https://doi.org/10.1111/j.1442-8903.2006.00263.x]

Key words: (<5 words): Monitoring, restoration, population ecology, woodland conservation

Figure 1. Location of babbler project works and other landcare works implemented since 1996 in the Sheep Pen Creek Land Management Group area and the two sub-districts used for the babbler study. (Source TFNVic)

Introduction: The Grey-crowned Babbler (Pomatostomus temporalis) (babbler) is a threatened woodland bird (classified as Endangered in the state of Victoria) that has declined substantially in overall distribution and abundance across much of its former range in southeastern Australia since European settlement.  Sheep Pen Creek Land Management Group area, in northern Victoria (Fig 1), was fortuitously the location of the largest known remaining babbler population in Victoria in the early 1990s (when this project began); and the focus of extensive land restoration programs from the 1980s onwards to help mitigate the impacts of erosion and dryland salinity, as well as biodiversity decline.  The original study, published in 2006, investigated the overall changes in tree cover across the district between 1971 and 1996 as a result of different land-management actions and responses of local babbler populations to those habitat changes.  The key finding was that in the Koonda sub-district which had a 5% overall increase in tree cover to 14% from 1971 to 2001, showed an increase in babbler numbers by about 30% (Table 1).   In the Tamleugh sub-district, tree cover increased by 1.3% to a total of 9%, with no change in babbler numbers.  The findings also showed that new babbler groups were preferentially colonizing new patches of vegetation established that suited their habitat needs.  Building on this research, the study concluded that future conservation programs needed to scale-up the extent of habitat restoration, target areas which were suitable for babbler colonization, and tailor incentive programs to assist with conservation of particular species.

Table 1. Changes in Grey-crowned Babbler numbers over time

Year Koonda Tamleugh
number of groups number of birds number of groups number of birds
1992 20 78 11 39
1993 20 89 10 34
1996 24 96 9 35
1997 24 102 8 30
1998 25 99 10 40
2000 26 97 10 43
2005 23 99 8 34

Further revegetation works undertaken. Since the initial study’s assessment of vegetation changes between 1971 and 1996, an additional 133 ha of vegetation has been restored or established as babbler habitat in Koonda district and 37 ha in the Tamleugh district (Figs 2 and 3, Table 2).  Extensive natural regeneration, supplemented by broadscale revegetation, has also occurred over more than 350 ha on five private conservation properties in the Koonda district,, contributing to substantial landscape change.  The wider landscape has also been identified as a statewide priority for nature conservation on private land, leading to increased conservation investment in permanent protection there by Victoria’s lead covenanting body – Trust for Nature.

Monitoring of outcomes: The monitoring that was carried out prior to the 2006 publication has not continued, leaving a knowledge gap as to how the population has fared in the context of the Millenium Drought and ongoing climate-change impacts. However, based on the original research’s initial findings, we conducted an experimental study with University of Melbourne to evaluate the effectiveness of habitat restoration in maintaining babbler survival. The study, published by Vesk and colleagues in 2015, compared the persistence and group size of babbler groups present in 1995 and subsequently in 2008 at a randomly selected set of stratified sites which had either had habitat works or none.  This study was conducted across a larger landscape of about 200,000 hectares which included Sheep Pen Creek Land Management Group area.  The study found that babbler group size decreased by about 15% over the 13 years at sites without restoration works.   At sites with restoration, average group size increased by about 22%, thereby effectively compensating for the overall reduction in numbers reported over that time.This increase also influenced subsequent demographic performance, with groups at restoration sites having higher breeding success and more fledglings than groups at control sites.

Another useful finding from this experimental study was the confirmation of the importance of particular habitat and landscape variables on babbler persistence.  In particular, abundance of large trees was a positive predictor of occupancy over time; and distance from the next nearest group was a negative predictor.

Figure 2. Changes in tree cover in the Koonda sub-district between 1971 (top),  and 2018 (bottom). (Source TFNVic).. (Source TFNVic)

Figure 3. Changes in tree cover in the Tamleugh sub-district between 1971 (top) and 2018 (bottom). (Source TFNVic)

Table 2.  Summary of additional habitat established or restored as part of the Sheep Pen Creek Grey-crowned Babbler project from 1996-2018, following the initial study period from 1971-1996.

District Number of sites Area (ha)
Koonda 62 133
Tamleugh 28   37
Other parts of landcare group and local babbler population area 29 103
Totals 119 273

Expansion of lessons to other districts: Building on the fundamental research conducted in Sheep Pen Creek Land Management Group area, similar habitat, landscape and babbler population assessments were subsequently undertaken in northwest Victoria near Kerang for the babbler populations found there.  Key results from these studies relevant to the initial Sheep Pen study were that the number of babbler groups in each sampled district was positively related to the proportion of woodland cover, especially the proportion of Black Box (Eucalyptus largiflorens) woodland habitat – the babblers’ preferred habitat in this region.  Conversely, the number of babbler groups was negatively associated with the proportion of land under intensive agriculture.  At the site scale, key positive predictors of babbler presence in Black Box habitat again included the abundance of large trees (> 60 cm dbh)

Lessons learned and future directions: The most valuable lesson learned since the initial paper was published was the power of the structured research project described above to evaluate the effectiveness of the babbler conservation program and inform future design and planning. The study further demonstrated the importance of taking a demographic approach to the species’ conservation needs, understanding what is happening across the whole population over time  and how habitat interventions can assist.  These lessons have since been applied usefully to other babbler projects  and more broadly to conservation of woodland birds.

The initial paper noted the importance of achieving landscape-scale change in vegetation extent, particularly in more fertile habitats. This has occurred to some extent within the Koonda district through a range of incentive programs, tender programs, covenanting programs and land purchase, but continues to achieve most gains on more infertile land. On fertile land, by contrast, there has been rapid land-use change to cropping over the past fifteen years, leading to reduced likelihood of those properties providing suitable habitat for babblers, as found in the study conducted in northwest Victoria.

The initial paper also suggested the benefit of developing tailored incentive programs for babblers and other threatened species with particular requirements to maximize potential conservation gains  and we suggest, based on Australian and overseas experiences,  that more specific incentive programs or more detailed criteria could assist.

Another important lesson learned was the difficulty in maintaining community-driven citizen-science monitoring, even with the best will in the world, without some over-arching organizational support and oversight.  We know that community monitoring for biodiversity conservation needs scientific input at the design and analysis stages; hence additional resources may also be required in terms of equipment or guidelines to help groups monitor effectively.  Modest government investments to conservation organisations with established biodiversity monitoring programs could usefully help address this issue.

Finally, the learnings from the Sheep Pen Creek Land Management babbler conservation project over nearly thirty years are that the landscape changes and that these changes are not always positive.  Land-use change is placing more pressure on  potential babbler habitat; and the eucalypt regrowth which was established and provided new nesting resources for a few years is now too tall to provide nesting habitat, but too dense and immature to provide suitable foraging habitat for another one hundred years.  Climate change is rapidly imposing constraints on the availability of food resources and breeding opportunities, exacerbated by increased competition for the same limited resources by exotic and native species.  For the Grey-crowned Babbler, the solution to all of these factors depends on ongoing commitment to the establishment or maintenance of their essential habitat needs and life-history requirements so that their life-cycle is provisioned for from generation to generation.

Stakeholders and Funding bodies:   Most of the targeted habitat works achieved for babblers in this landscape has occurred through funding support from the Australian government through its Natural Heritage Trust and Caring for our Country programs.  Broader habitat protection and restoration has occurred primarily with funding support to landholders from the Goulburn Broken Catchment Management Authority (GBCMA).  The Norman Wettenhall Foundation, along with GBCMA, was instrumental in enabling the research by University of Melbourne, which was also aided by the extensive voluntary support of Friends of the Grey-crowned Babbler.  Not least, local landholders continued to support the project and continue to protect or restore parts of their properties to assist with babbler conservation.

Contact information: [Doug Robinson, Trust for Nature, 5/379 Collins Street Melbourne, Victoria 3000, Australia.  dougr@tfn.org.au, (03) 86315800 or 0408512441; and  School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia.

 

 

 

 

Comments Off on Is revegetation in the Sheep Pen Creek area, Victoria, improving Grey-crowned Babbler habitat? – UPDATE of EMR feature

Posted in agricultural lands, Community involvement, Cultural & socio-economic issues & solutions, Ecosystem services, EMR 20th anniversary updates, Erosion issues & solutions, Fauna & habitat, Integrating ecosystems & industries, Landscape pattern & design, reconstruction, Restoration & management theory, Sclerophyll communities, Victoria