Category Archives: Assisted regeneration

Highly resilient response at a Cooma restoration site points to native plant adaptation to drought and short growing seasons

Posted on 6 October 2022 by | Comments Off on Highly resilient response at a Cooma restoration site points to native plant adaptation to drought and short growing seasons

Tein McDonald

Figure 1. One of the many ‘before and after’ photo pairs showing how, (a) at the start of the project in 2019, a near-monoculture of African Love Grass was persisting even during the drought – but (b) native regeneration boomed after two seasons of good rain and regular spot-spraying of the prolific and diverse weed that regenerated along with the natives.

Introduction. Assisted regeneration works have been undertaken over three seasons at a small (4ha) but uncleared privately owned bush block on the urban boundary of Cooma in the southern tablelands of NSW. Degradation at the start of the project in 2019 reflected past land uses. Flatter areas disturbed by historic light sheep grazing and vehicular tracks appeared in poor condition, with infestations of serious weed, particularly bird spread shrubs and pasture weeds. Drought-induced dieback occurred across the site, along with evidence of overgrazing by macropods and rabbits. Most of the site’s extensive (lichen and moss-covered) granite rocky knolls, however, remained undisturbed and in good condition.

Results of the works were expected to be gradual, given that the area’s annual average rainfall was around 538 mm and growing seasons short due to the southern tablelands’ relatively cold climate. While these lower expectations were reasonable, they did not factor in the above average rainfall of the 2021-21 season and, particularly, the very high and evenly distributed rainfall of the 2021-22 growing season.

Vegetation community. The main vegetation association on the site (and the Reserve) is Ribbon Gum (Eucalyptus viminalis)-E Black Cypress Pine (Callitris endlicheri) grassy woodland, with co-dominant trees including Candlebark (E. rubida), Apple Box (E. bridgesiana), Broad-leaved Peppermint (E. dives) and Mountain Gum (E. dalympleana). Sweet Bursaria (Bursaria spinosa), Red-stemmed Wattle (Acacia rubida) and Woolly Grevillea (Grevillea lanigera) are common in the mid-storey, along with six Fabaceae shrubs. Out of the 88 native vascular plant species, 63 are herbaceous (15 grass species and 48 forb species including 13 Asteraceae) species.

Weeds. At least 40 weed species occur on site, falling into two groupings – shrubs and groundcovers. The most prevalent shrubs were Orange Firethorn (Pyrocantha spp.) and Cotoneaster (Cotoneaster spp.) The most prevalent groundcovers were African Love Grass (Eragrostis curvula), Yellow Catsear (Hypochaeris radicata), Smooth Catsear (Hypochaeris glabra), St Johns Wort (Hypericum perforatum), Hare’s Foot Clover (Trifolium arvense), Proliferous pink (Petrorhagia nanteuilii) and Fleabane (Conyza sp.).

Works undertaken. Works have focused on the systematic and careful spot-spraying of individual weeds, rigorously following up to avoid the weed recharging soil seed banks. Cut brush was also laid down in a brickwork pattern along the contours to retain waterflow (where erosion was an issue) or deter macropods (where overgrazing was an issue, see https://youtu.be/4hmLFSL_kHQ ).

At the commencement of the works, ‘before’ photos were taken from eight pegged photopoints and at least 10 other informal ‘before’ shots across a wider range of subsites. Condition class mapping was undertaken using a 5-scale system adapted from the system used by the NSW National Trust since the 1980s.

Figure 3. (a) Before and (b) after treatment at the ‘Rabbit flat’ subsite. This area was highly drought affected and overgrazed by kangaroos and rabbits in 2019. Weed trimmings were laid on the site to reduce sheet erosion and grazing. Weeds were regularly controlled, particularly African Love Grass and Hare’s Foot Clover. Drought breaking rains triggered germination of mainly Golden Everlasting (Chrysocephalum apiculatum), New Holland Daisy (Vittadinea cuneata) and range of other natives. Very little African Love Grass and other weeds now persist at this site.

Weed treatments (totalling approx. 250 hours) were carried out over three growing seasons (Spring- Autumn) starting in December 2019 and extending till May 2022 (Table 1). By far the most hours (237) were directed to precision knapsack spot-spraying of groundcover weeds, with relatively few hours treating shrub weeds. The highest input was required in the third season, due to its exceptionally favourable rainfall (Fig. 2) when we needed to increase our inputs to treat all herbaceous weed across the whole site prior to their setting seed and recharging seed banks.

Table 1.  Hours involved in spot-spraying of groundcover weed for each of the three seasons.

Season 1  (2019-20) Season 2(2020-21) Season 3(2019-20)
77 56

Figure 2. Rainfall records at the site over three growing seasons from December 2019 to May 2022 (Blue bars is rainfall recorded at East St, Cooma; the red line the mean rainfall recorded at the Cooma Visitor’s Centre).

Outcomes to date. While the site is far from fully recovered and works will be ongoing, results to date are encouraging. Figures 1 and 3 are three of many before and after photo pairs that compare the condition of all subsites prior to work with native plant recovery by January 2022 –24 months after the first drought-breaking rains. (Also see multiple photos at https://youtu.be/wjNviPl-MqY .) The condition classifications prior to works and at 3 seasons after works are shown in Figure 4.

In general most sites appear to have moved up in condition by at least one class; there is now substantially more area of medium to high condition after treatment compared to prior to treatment. However this result is still somewhat uncertain as the degree to which some of the Hare’s-foot Clover may have matured prior to spraying is unclear. The test of condition will be in Spring during the next above-average rainfall year.

 

Figure 4. Condition mapping (a) before and (b) after 3 seasons using a five-level condition classification system. The two maps show an increase in area of the green end of the spectrum (higher condition) and a reduction in area at the red end of the spectrum (lower condition). [The colour-coding and criteria are based on a four-level system used traditionally in the bush regeneration industry developed by the National Trust in the 1970s then modified during the 1990s by T. McDonald and subsequently resequenced to align with the 1-5 sequencing used in the 5-star system of the National Restoration Standards.]

Lessons learned and future directions.  The resilience level of this cold-climate, drought-affected plant community proved to be surprisingly high and growth relatively rapid after highly favourable rainfall. This may indeed be due to the species’ adaptation to periodic drought and short growing seasons.  Importantly (as elsewhere) such resilience also lends a capacity for natives to recover after periods of weed domination if that weed is removed.

It is logical to view the pattern of drought followed by highly favourable rainfall as somewhat similar to wildfire followed by highly favourable rainfall.  In such circumstances there is benefit in systematically treating as large an area as possible to (i) take advantage of the opportunities for rapid recovery of natives and (ii)  avoid massive and unusual recharge of weed seedbanks that could set a site’s condition back by many decades. While the landholders in this case did the work themselves and could increase or decrease work as required per season, cases relying on public funding would benefit from contingency funding being set aside for supporting additional restoration inputs in high rainfall seasons post-fire or post-drought.

Stakeholders.  The works were carried out by the block’s landholders Tein McDonald and Graeme Little.   Friends of Grassland helped with plant identification and encouragement and provided a small grant  to offset the costs of herbicide and equipment.

Contact:  Tein McDonald teinm@ozemail.com.au

 

 

 

 

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Posted in Assisted regeneration, Bush regeneration, Grassland/grassy understorey, New South Wales, semi-arid, Techniques & methodology, Weed issues & solutions

Regeneration of indigenous vegetation at Third Reedy Lake as it has dried over summer and autumn 2022

Posted on 24 June 2022 by | Comments Off on Regeneration of indigenous vegetation at Third Reedy Lake as it has dried over summer and autumn 2022

Damien Cook

Introduction.  Third Reedy Lake is a freshwater wetland in the Kerang region in north central Victoria. It is part of the Kerang Wetlands Ramsar Site, which means that it is recognised as being of international significance for wetland conservation as it supports threatened plant and animal species and ecological communities and rookeries of colonial nesting wetland birds.

Prior to European occupation this wetland, along with Middle Lake and Reedy Lake, would have been inundated only when floodwaters came down the Loddon River and caused the intermittent Wandella and Sheep Wash Creeks to flow. At that time the wetland experienced a natural wetting and drying cycle, filling up from floodwaters and drying out completely between floods, which occurred on average once every 3 to 4 years.

In the 1920s, however, this natural wetting and drying cycle was discontinued. Third Reedy Lake became part of the Torrumbarry Irrigation Scheme. Water was diverted out of the Murray River at Torrumbarry Weir and made to flow through a series of natural wetlands including Kow Swamp, the Reedy Lakes, Little Lake Charm and Kangaroo Lake to deliver water to irrigate farms. The lakes and swamps became permanently inundated.  While this meant farmers had a reliable supply of water it also profoundly altered the ecology of the wetlands (Fi. 1).

Figure 1. Third Reedy Lake in February 2013 prior to being bypassed. Continuous inundation for around a century had drowned the native vegetation, leaving only skeletons of trees. (Photo D. Cook)

Trees such as River Red Gum (Eucalyptus camaldulensis) and Black Box (E. largiflorens) were drowned, lake bed plants that relied on a drying cycle could no longer grow and the ecological productivity of the wetlands was massively reduced. The density of wetland birds has been found to be positively correlated to wetland productivity and this metric has been used in a variety of ecological studies to compare the use of different habitats by wetland birds. During bird counts conducted in 2018 the highest density of birds on Third Reedy Lake was about 5 birds/hectare. In contrast the naturally intermittent Lake Bael Bael supported over 60 birds/hectare, a density 12 times higher. While Third Reedy Lake supported a maximum of 17 wetland bird species Lake Bael Bael supported a maximum 38 wetland bird species.

Works undertaken

Hydrological works.  Third Reedy Lake was deemed to be inefficient for moving water due to losses caused by evaporation and so it was intentionally bypassed by the irrigation scheme in 2020. The lake therefore dried for the first time in one hundred years over the summer of 2022. Environmental water will be periodically delivered to the wetland in the future to mimic its natural wetting and drying cycle and assist ecological recovery.

Revegetation works. Over 2000 River Red Gum trees and 1000  understorey plants, including Tangled Lignum (Duma florulenta) and Southern Cane-grass (Eragrostis infecunda), have been planted across the centre of the lake where no natural regeneration was likely to occur in the short to medium term. Members of the local Barapa Barapa and Wemba Wemba Traditional owner communities were employed to plant the trees and other plants (Fig. 2). The Barapa Barapa and Wemba Wemba Traditional Owners have a strong interest in the wetland because of its cultural values.


Figure 2. Uncle Trevor Kirby with a Red Gum he has just planted and guarded at Third Reedy Lake April 2022. . Virtually no native vegetation remained visible on the lake bed immediately after the long inundation. (Photo T. McDonald)

The River Red Gum seedlings have been planted next to dead River Red Gum stumps to replicate the original woodland structure of the wetland (Fig  3). Planting next to the stumps has other advantages; they provide shelter from the wind and sun and soil carbon and moisture levels are highest close to the rotting wood.

Figure 3. River Red Gum seedling planted next to an old red gum stump, Third Reedy Lake May 2022. (Photo D. Cook)

Results to date.  In the first 3 months without inundation the lakebed muds dried out, followed by deep cracking (Fig 2). Planted trees thrived as there was still ample moisture in the sub-soil.  Site inspections in May 2022 revealed that substantial natural regeneration of the wetland has begun (Fig. 4).

After 100 years without drying it was not known if any seed bank of the original lakebed vegetation would have survived. However, 46 native species have been recorded growing on the lakebed since the last of the water evaporated from the lake in April 2022. This includes two threatened species: Floodplain Groundsel (Senecio campylocarpus) and Applebush (Pterocaulon sphacelatum) (Fig. 5) . The germination of Applebush is particularly surprising given that this is only the fourth record of this plant in Victoria, the species being more common in the arid centre of Australia. Other indigenous species that have regenerated on the lakebed are shown in Figs 6 and 7.

Figure 4. Lake bed herbs regenerating after the drying phase, at Third Reedy Lake, May 2022 . A total of 46 native species have been recorded as having regenerated on the lakebed since the last of the water evaporated from the lake in April 2020 (Photo D. Cook)

Figure 5. Among the 46 native species regenerating is Applebush (Pterocaulon sphacelatum) which is particularly surprising as it is listed as endangered in Victoria and known to occur in only three other locations. (Photo Dylan Osler)

Figure 6. Spreading Nut-heads (Sphaeromorphaea littoralis), Third Reedy Lake May 2022. This species is uncommon in the Kerang region, the closest records to Third Reedy Lake being from the Avoca Marshes. (Photo D. Cook)

Figure 7. Golden Everlasting (Xerochrysum bracteatum) and Bluerod (Stemodia florulenta) make an attractive display of wildflowers. These species are uncommon at present but if weeds are controlled adequately, they should recolonise much of the wetland floor. (Photo D. Cook)

River Red Gum regeneration has been localised on the bed of the lake and has mainly occurred on the fringes close to where living Red Gum trees have shed seed. The densest Red Gum regeneration has occurred on a sandy rise close to the inlet of the lake, where the trees have grown rapidly (Figs 8 and 9). Many of the seedlings that have germinated on the edge of the lakebed are being heavily grazed by rabbits or wallabies.

Figure 8. Regenerating Red Gums and native grasses and sedges on a sandy rise near the inlet of Third Reedy Lake, May 2022.(Photo D. Cook)

Figure 9. River Red Gum seedling on cracking clay soil that has germinated near the lake edge. Many of these seedlings are being heavily grazed, probably by rabbits or wallabies. (Photo D. Cook)

The young trees will take many years to develop the hollows required by many species of wildlife, but hopefully the old stumps will persist for some time to provide this important habitat feature (Fig 10). When these trees grow large enough, they will provide shady nesting sites for colonial nesting wetland birds such as Australasian Darter (Anhinga novaehollandiae) (Fig. 10) and Great Cormorant  (Phalacrocorax carbo) and replace the dead standing trees as they rot and fall over.

Figure 10. Australasian Darter chicks on a nest in a live River Red Gum in the creek that joins Middle Lake to Third Reedy Lake. (Photo D. Cook)

Stakeholders: Barapa Barapa, Wemba Wemba, Goulburn-Murray Water, North Central Catchment Management Authority and Kerang Wetlands Ramsar Site Committee

Contact:  Damien Cook, restoration ecologist, Wetland Revival Trust, Email: damien@wetlandrevivaltrust.org

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Posted in agricultural lands, Assisted regeneration, Community involvement, Ecosystem services, Environmental watering, Fauna & habitat, Grassland/grassy understorey, Indigenous Knowledge, Indigenous land & sea management, Sclerophyll communities, Techniques & methodology, Victoria, Wetland

Biological and cultural restoration at McDonald’s Swamp in northern Victoria, Australia

Posted on 24 June 2022 by | Comments Off on Biological and cultural restoration at McDonald’s Swamp in northern Victoria, Australia

Dixie Patten (Barapa Wemba Working for Country Committee) and Damien Cook (Wetland Revival Trust.

Introduction. McDonald’s Swamp is a 164-ha wetland of high ecological and cultural significance, and is one of the Mid Murray Wetlands in northern Victoria. The restoration this wetland is part of broader project, led by the Indigenous Barapa Wamba Water for Country Committee in collaboration with the Wetlands Revival Trust, to address the loss of thousands of wetland trees and associated understorey  plants that were killed by poor agricultural and water management that caused prolonged water logging and an elevated the saline water table.

Figure 1. Laura Kirby of the Barapa Wamba Water for Country restoration team beside plantings of two culturally important plants that are becoming well established; Common Nardoo (Marsilea drummondii) and Poong’ort (Carex tereticaulis). (Photo D. Cook.)

The project has a strong underpinning philosophy of reconciliation as it is a collaboration between the Wetland Revival Trust and Aboriginal Traditional Owners on Country – access to which was denied to our people for a long time, disallowing us to practice our own culture and have places to teach our younger generations.  One of the main aims of the project is  to employ Barapa and Wemba people on our own land (Fig 1), not only to restore the Country’s health but also to provide opportunities for a deeper healing for us people. Many of the species we are planting are significant cultural food plants or medicine plants. Indeed it’s actually about restoring people’s relationships with each other –Indigenous and non-Indigenous Australians – and maintaining our connection to  Country.

Over recent years the hydrology of many wetlands in the Kerang region has been vastly improved by a combination of drought, permanently improved irrigation practices in the catchment and the delivery of environmental water.  This has restored a more natural wetting and drying cycle that will enable regeneration of some prior species, largely through colonisation from the wetland edges and through reintroduction by waterbirds.

However, supplementary planting is needed to accelerate the recovery of keystone species at all strata and the ~50 ha of the wetland that has been assessed as highly degraded with little potential f or in-situ recovery from soil-stored seedbanks.

Figure 2. Aquatic species planted at McDonald’s Swamp, including Robust Water-milfoil (Myriophyllum papillosum), Common Water Ribbons (Cycnogeton procerum) and the endangered Wavy Marshwort (Nymphoides crenata). (Photo D. Cook)

Works undertaken: To date the project has employed 32 Traditional Owners, planting out and guarding canopy trees to replace those that have died, undertaking weed control, and replanting wetland understorey vegetation.

Over a period of 5 years,, around 60% of the presumed pre-existing species, including all functional groups, have been reintroduced to the site, involving 7000 plants over 80 ha of wetland. This includes scattered plantings of the canopy species River Red Gum (Eucalyptus camaldulensis), Black Box (Eucalyptus largiflorens) and Eumong (Acacia stenophylla).  Dense nodes have also been planted of a wide diversity of herbaceous wetland species including water ribbons (Cycnogeton spp.), Nardoo (Marsilea drummondii) and Old Man Weed (Centipeda cunninghamii). These nodes have been protected from waterbird grazing by netting structures for 3-6 months, after which time they have reproduced and spread their seeds and begun recruiting throughout the broader wetland..

Some areas of the swamp are dominated by overabundant native reeds due extended inundation in the past.  Such reeds – including Cumbungi (Typha orientalis) and Common Reed (Phragmites australis) – will be future targets for burning or cutting followed by flooding by environmental watering to reduce their abundance prior to reintroduction and recolonization by other indigenous species.

Figure 3. Prolific regeneration of the nationally endangered Stiff Grounsel (Senecio behrianus). The species is presumed extinct in South Australia and New South Wales and is now only known only from 5 wild and 6 re-introduced populations in Victoria. (Photo G Little)

Outcomes to date: Very high establishment and growth rates have been attained for the canopy tree species, many individuals of which have flowered and set seed within the 6 years since project commencement.  All the planted understorey species are now recruiting very well – particularly the Water Ribbons (Cycnogeton procerum and C. multifructum), Floating Pondweed (Potamogeton  cheesmannii), Common Nardoo (Marselia drummondii), Wavy Marshwort (Nymphoides crenata), Water Milfoils (Myriophyllum papillosum  and M. crispatum), Forde Poa (Poa fordeana), Swamp Wallaby-grass  (Amphibromus nervosus), River Swamp Wallaby-grass (Amphibromus fluitans) and the nationally endangered Stiff Groundsel (Senecio behrianus) (Fig.  3.).  The important Brolga (Antigone rubicunda) nesting plant Cane Grass (Eragrostis infecunda) has also spread vegetatively.  Where hundreds of individuals were planted, there are now many thousands recruiting from seed, building more and more potential to recruit and spread within the wetland.

After 7 years of a more natural wetting and drying regime, natural regeneration has also occurred of a range of native understorey species including populations of the important habitat plant Tangled Lignum (Duma florulenta), Lagoon Saltbush (Atriplex suberecta) and Common Spike-rush (Elaeocharis acuta) (Fig 4.).

Figure 4. Planted River Red Gum (Eucalyptus camaldulensis) and naturally regenerating Tangled Lignum (Duma florulenta) and a range of other native colonisers and some herbaceous weed at McDonald’s Swamp some6 years after hydrological amendment and supplementary planting. (Photo T McDonald)

Stakeholders:  Barapa Land and Water, Barapa Wamba Water for Country Committee, Parks Victoria, Department of Environment, Land, Water and Planning and the North Central Catchment Management Authority.

Contact: Damien Cook, Wetland Revival Trust, Email: damien@wetlandrevivaltrust.org

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Posted in agricultural lands, Assisted regeneration, Community involvement, Cultural & socio-economic issues & solutions, Ecosystem services, Environmental watering, Fauna & habitat, Grassland/grassy understorey, Indigenous Knowledge, Indigenous land & sea management, Landscape pattern & design, Techniques & methodology, Threatened species & communities, Victoria

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

Post-wildfire recovery at a wet sclerophyll/rainforest ecotone close to housing at Wanganui NSW

Posted on 23 March 2021 by | Comments Off on Post-wildfire recovery at a wet sclerophyll/rainforest ecotone close to housing at Wanganui NSW

Joanne Green

Introduction. The Mt Nardi fire, on Wed 13th Nov 2019, provided an opportunity to observe the effects of a relatively low intensity burn at a wet sclerophyll/rainforest ecotone on an 18 acre rural residential property at Wanganui, NSW.

Prior to the fire the vegetation had not been burned for 50 years and was dominated by Brush Box (Lophostemon confertus), Red Bloodwood (Corymbia gummifera) and Forest Oak (Allocasuarina torulosa) –  with a mesic understory of rainforest species including Red Bopple Nut (Hicksbeachia pinnatifolia ), Jackwood (Cryptocarya glaucescens), Bangalow Palm (Archontophoenix cunninghamiana)  and  Tree Heath (Trochocarpa laurina).  The forest was on a trajectory from wet sclerophyll towards a palm-dominated forest.

Since the fire,  the recovery has reset the ecosystem to a wet sclerophyll community with a diversity of heathy species in the understorey, although there is also massive germination and resprouting of rainforest species that indicates that the rainforest understorey will return over time. Table 1 at the end of this summary shows the recovery of both sclerophyll and rainforest species, and their presence or absence above ground prior to the fire.

Figure 1. Dead Bangalow Palm amid a sea of Brown Kurraong seedlings post fire. (Photo: J. Green)

 

Figure 2. Resprouting saplings of (a) Bolwarra and (b) Creek Fig (Photo J. Green)

Mortality and recovery.

Resprouting:  The fire varied in intensity as it burned downslope. The highest intensity was at the edge of the National Park at the highest elevation above a rocky face. Turpentine (Syncarpa glomulifera), Lomandra (Lomandra longifolia), heath species and younger trees appeared to be killed by fire. While Turpentine has not yet resprouted, Lomandra has resprouted and heath species such as Acacia and Zieria have regrown from seedlings.  Bangalow Palms (Archontophoenix cunninghamiana) are completely dead wherever the fire burned to their tops (growing points) and perhaps many more are dying, indicated by the presence of a fungus on their trunks. One tall Brushbox (Lophostemon confertus) is completely dead.

A community with old growth Forest Oak (Allocasuarina torulosa) is further downslope closer to the rainforest lined creek. The roots system of these trees, burned under the ground and the fire could only be doused by digging out the peat-like root system. Some of the Forest Oaks died but most have recovered.  Taller canopy trees of rainforest and sclerophyll species died back but are resprouting. Midstorey trees, less than 8m, are largely dead, dying or resprouting from the base (coppicing).  The trunks are completely dead but there are many root suckers of species such as Jackwood (Cryptocaryia glaucescens), Bolwarra (Eupomatia laurina), Grey Possumwood (Quintinia verdonii) and the rare Red Bopple Nut (Hickbeachia pinnalifolia).

Treeferns such as Cyathea australis, C. cooperi and C. leichhardtiana were the first resprounters and ground ferns such as Soft Bracken (Hypolepis muelleri) are proliferating following the  rain since the fire event.

Figure 3. Proliferation of rainforest pioneers germinating after fire including Poison Peach (Trema aspera), Pencil Cedar (Polyscias murrayi) and Bleeding Heart (Homolanthus populifolius). (Photo J. Green)

 

Figure 4. Heath species such as Zieria (Zieria smithii) pictured at the right. germinated alongside rainforest species despite not being in the previous above-ground flora. (Photo: J. Green)

Seed germination: Rainforest species germinating included: Red Cedar (Toona ciliata) , Pencil Cedar (Polyscias murrayi), Brown Kurrajong (Commersonia bartramia), Red Ash (Alphitonia excelsa) and Corkwood (Duboisia myoporoides).  Heath species recruiting included: a large amount of Tree Pea (Daviesia arborea), Zieria (Zieria smithii), Prickly Acacia (Acacia ulicifolia), and Hibbertia spp. Herbaceous species included: Forest Lobelia (Lobelia trigonocaulis),  Kreysigia (Tripladenia cunninghamii), Hairy Tree Foil Desmodium rhytidophllum and other vines of the pea family are covering large areas of the ground.

Weed regeneration

Alongside the natives,  diverse weeds are proliferating after fire, representing all growth forms. Some weed species may be playing a facilitation role for rainforest recovery, while others should be  targeted to reduce their inhibiting effect on native regeneration. Given the level of regeneration across functional groups, this community is likely to benefit from assisted natural regeneration focusing on removal of weed that is competing with native regeneration.  Where possible it is desirable to use the opportunity of the wildfire to deplete populations of weed at the site to increase the community’s resilience to future fire. No reintroductions or seed input is needed at the site.

Future directions.  Consideration needs to be made as to which ecosystem will be the target for future management.  Retaining a sclerophyll overstorey is desirable for habitat values and hence allowing replacement of those individuals that died will be important for future forest dominants.  The use of fire as a control method to control the massive germination of rainforest seedlings and Bangalow Palm dominants is under consideration. For the healthy understorey elements to remain in the soil seed bank for future regeneration would at least require their retention until they have flowered, fruited and recharged the soil seed bank.  But consideration will be given to retaining more fire-resistant rainforest vegetation on the side of the forest closer to the house to act as a fire buffer to supplement the existing 50m fuel free zone.

Contact: Joanne Green, Email jogreen909@gmail.com

Table 1.

SPECIES HABITAT TYPE PRESENCE /ABSENCE BEFORE FIRE RECOVERY MODE
Botanical Name Subtropical Rainforest = STRF, Wet Sclerophyll = WS, Dry Sclerophyll = DS P /A Seed = S, Epicormic growth = EP, Coppice = COP, R = Resprout
TREES AND SHRUBS      
Acacia ulicifolia DS P S
Acacia melanoxylon STRF P S
Acmena smithii STRF P COP
Allocasuarina torulosa WS P EP
Alphitonia excelsa STRF P S/COP
Alphitonia petrei STRF P S
Archirhodomyrtus beckleri STRF P COP
Archontophoenix cunninghamiana STRF P S/Dead
Breynia oblongifolia STRF P S
Commersonia bartramia STRF P S
Cordyline rubra STRF P COP
Corymbia intermedia WS/DS P EP
Cryptocarya erythroxylon STRF P COP
Cryptocarya glaucescens STRF P COP
Daviesia arborea WS/DS A S
Diospyros pentamera STRF P COP
Diploglottis australis STRF P COP/Dead
Duboisia myoporoides STRF P S/COP
Elaeocarpus reticulatus STRF P COP
Eucalyptus microcorys DS P EP
Eucalyptus pilularis DS P EP
Eupomatia laurina STRF P COP
Flindersia bennettii STRF P COP
Ficus coronata STRF P S/COP
Glochidion ferdinandi STRF P COP
Hickbeachia pinnalifolia STRF P COP
Homalanthus populifolius STRF A S
Jagera pseudorhus STRF P COP
Leptospermum petersonii DS P COP/S
Lophostemon confertus WS P S/COP
Macaranga tanarius STRF A S
Melicope elleryana STRF P S
Myrsine variabilis STRF/WS P S
Nematolepis squamea DS A S
Neolitsia dealbata STRF P COP
Ozothamnus diosmifolius WS/DS P S
Persoonia media WS P S
Pilidiostigma glabrum STRF P COP
Polyscias  murrayii STRF A S
Polyscias sambucifolia STRF A S
Quintinia verdonii STRF P COP
Schizomeria ovata STRF P COP
Solanum mauritanium Non – Native A S
Syncarpia glomulifera WS P COP/Dead
Synoum glandulosum STRF P COP
Trema tomentosa STRF P S
Trochocarpa laurina WS P COP
Wilkea huegeliana STRF P S
Zieria smithii  WS A S
       
VINES AND CLIMBERS      
Billardiera scandens WS A S
Geitonoplesium cymosum STRF P S
Desmodium rhytidophllum WS/DS A S
Hibbertia dentata STRF P S
Hibbertia scandens STRF/WS P S
Kennedia rubicunda STRF A S
Morinda jasminoides STRF/WS P S
Rubus moluccanus STRF/WS P S
Smilax australis STRF/WS P S
Stephania japonica var. discolor STRF P S
       
FORBES AND GROUNDCOVERS      
Alpinia caerulea STRF/WS P R
Dianella caerulea STRF/WS P R
Entolasia stricta WS P S
Gahnia appressa WS P S
Lepidosperma laterale WS P R
Lobelia trigonocaulis STRF/WS P S/R
Lomandra longifolia WS P R
Oplismenus aemulus STRF/WS P S
Oplismenus imbecillis STRF/WS P S
Oplismenus undulatifolius STRF/WS P S
Pimelea ligustrina subsp. ligustrina STRF/WS A S
Tripladenia cunninghamii STRF/WS P S/R
Viola banksii STRF/WS A S
       
FERNS      
Adiantum hispidulum STRF/WS P R
Blechnum cartilagineum WS P R
Blechnum nudum STRF P R
Cyathea australis STRF/WS P R
Cyathea cooperi STRF P R
Cyathea leichhardtiana WS P R
Doodia aspera STRF/WS P R
Hypolepis muelleri STRF P R
Pteridium esculentum STRF/WS p R
Sticherus lobatus STRF p R
       

 

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Posted in Assisted regeneration, Bush regeneration, Fire Ecology & Management, New South Wales, Rainforest, Sclerophyll communities

Regenerating and planting of rainforest buffers to protect homes and rainforest from future fires

Posted on 23 March 2021 by | Comments Off on Regenerating and planting of rainforest buffers to protect homes and rainforest from future fires

Joanne Green, Rainer Hartlieb and Zia Flook

Introduction. The wildfires of November and December, 2019, burnt over 5,500 hectares of Nightcap National Park and the surrounding areas, including the rural communities of Huonbrook and Wanganui inland from Byron Bay in NSW, Australia. The fires occurred during a period of extreme fire risk after 2 years with below average rainfall. They mainly burnt the sclerophyll forest along the ridgetops, but the extreme conditions also saw fire burn the edge of the rainforest where it was eventually extinguished.

This summary reports on actions on one multiple occupancy property in Huonbrook, NSW after an ember attack from the Mt Nardi fire entered the property in the early hours of the 9th November 2019. During the fire, residents evacuated.  Their homes were saved but they returned to find that the fire burnt an area of eucalypts  – mainly Flooded Gum (Eucalyptus grandis) and several bamboo species that had been planted during the late 20th century to reforest an area where subtropical rainforest had been-long cleared for dairy farming. The plantings had also become infested with weed including Camphor Laurel (Cinnamomum camphora) and Lantana (Lantana camara), the latter increasing their combustibility under dry conditions. After the fires, the landholders sought solutions that could provide a more fire-resistant barrier to reduce potential fire threat to homes and the nearby remnant rainforest. As a result they opted to restore the buffer zone with the more fire-retardant subtropical rainforest that had been the original native vegetation of the area.

Figure 1. Multiple native and weed species germinated after fire. (Photo Rainforest 4)

Figure 2. Prolific germination of the wind-dispersed Red Cedar (Toona ciliaris), among many rainforest species germinating and resprouting on site. (Photo Joanne Green)

Works undertaken. Starting in March 2020, with support from Madhima Gulgan’s Indigenous bush regeneration team, Huonbrook residents and landowners commenced work on the site. The first task in any zone to be treated was to clear the debris sufficiently to allow access for weeding and planting. The second task was to identify any subtropical rainforest species (germinating after the fire) that were to be retained and to note areas that were bare and would be suited to plantings. (No planting was done where there was any natural regeneration.)  The third task was to remove prolific exotic weeds, while protecting the natives, with the final task involving planting, staking and tree guarding.

The main weed species on site were Lantana, Running Bamboo (Phyllostachys spp.), Kahill Ginger (Hedychium gardnerianum), Winter Senna (Senna x pendula), and Inkweed (Phytolacca octandra). A total of 12 rainforest tree species germinating included the secondary species Red Cedar (Toona ciliaris) and Celerywood (Polyscias elegana) and the pioneers Red Ash (Alphitonia excelsa), Macaranga (Maccaranga tanarius) and Bleeding Heart (Homolanthus populifolius). A total of seven native rainforest understorey species  resprouted including Dianella (Dianella caerulea), Native Ginger (Alpinia caerulea.) and Cordyline (Cordyline petiolaris).

Figure 3. Madhima Gulgan’s Indigenous bush regeneration team assisting  landholders with post-fire weeding.  This work revealed where understorey natives were regenerating and where gaps required planting. (Photo Rainforest 4)

Some  300 rainforest trees (around 30 species) and another 300 understorey plants have been planted at the site to date from May-Sept 2020, with a total of 3600 plants proposed to be planted on additional fire affected sites as part of this project. Locally occurring tree species planted to date include Lillipilly (Acmena smithii), Native Tamarind (Diploglottis australis), Firewheel Tree (Stenocarpus snuatus), and Long-leaved Tuckeroo (Cupaniopsis newmanii) Understorey species planted included Dianella, Lomandra, Native Ginger and Cordyline.  All required tree guards to protect them from browsing by the native Red-necked Pademelon (Thyogale thetis).

After the planting, more natural regeneration of weed and natives occurred, particularly of the ground ferns; Harsh Ground Fern (Hypolepis muelleri), Binung Fern (Christella dentata), and Soft Treefern (Cyathea cooperi). Since the rain in autumn 2020 and the above average rainfall year that has followed, the landholders are managing weed in the regeneration and plantings together and work is now extending into the unburnt buffer zone.

Figure 4. A total of 300 containerised plants were installed to reinstate lowland subtropical rainforest on the site and provide a less fire prone vegetation buffer to protect residential dwellings. (Photo Joanne Green)

Figure 5. Diagram of location of the buffer plantation in relation to dwellings. (Diagram. Joanne Green)

Results to date: Nearly 12 months after planting has seen a nearly 100% survival rate and many of the planted trees have grown to an average height 1-2m. The number of native rainforest species on site now is approximately 25 tree and 23 understorey species and vines.  Ferns cover 40% of the site. The difference between the number planted and the number on site (18 species) can be attributed to natural regeneration.

Further colonisation of rainforest species is expected over time. Whilst, in hindsight, we see that much of the site could have been captured by natives as a result of  weed management alone, the planting has added a broader diversity of species, and will accelerate the process of succession to a more mature rainforest stand.

Acknowledgements: The Madhima Gulgan Indigenous bush regeneration team was funded by the inGrained Foundation and the Rainforest 4 Foundation. See https://www.rainforest4.org/. Technical advice was provided by Joanne Green.

Contact: Rainer Hartlieb, Huonbrook landholder, rainerhart@aapt.net.au and Zia Flook, Rainforest 4 Foundation Conservation Program Manager, zia@rainforestrangers.org

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Posted in Assisted regeneration, Bush regeneration, climate change, Community involvement, New South Wales, Rainforest, Threatened species & communities

Second trial of watering device design to facilitate seed dispersal into revegetation sites

Posted on 4 October 2020 by | Comments Off on Second trial of watering device design to facilitate seed dispersal into revegetation sites

Amanda Freeman

Figure 1. Watering device on stand with camera above.

Introduction. This summary reports on methods and results of a trial to improve the design of a watering device. (See preliminary trial in EMR summary). This trial drew upon lessons learned In the “Kickstart” pasture conversion project,  (see https://authors.elsevier.com/a/1bhz81L%7EGwOHhQ) where perches and water basins were installed on two private properties in the upper Barron, Queensland, with the aim of catalysing rainforest regeneration.  The seeds of 31 species of bird-dispersed forest trees and shrubs were deposited in water basins, largely due to Pied Currawong (Strepera graculina) using the water to regurgitate seeds. The Kickstart Project demonstrated that there is potential for supplementary water to enhance seed dispersal into revegetation sites; however, the seeds regurgitated into basins in that study were not deposited in sites suitable for germination, limiting the basins’ usefulness as restoration tools.

Our 2016 EMR Project Summary described a watering device designed to overcome this problem of seed being deposited in water receptacles.  The trial was conducted at the School for Field Studies property near Yungaburra, Queensland and this summary reports the results of our trial which aimed to identify whether frugivorous birds would use our watering device. We also assessed the amount of maintenance the watering device required to function effectively.

Figure 2. A Lewin’s Honeyeater (Meliphaga lewinii) at a watering device, May 2017.

Watering Device Trial. In July 2016, three 3 x 3m plots were established in an approximately 120 x 30m area of disused pasture at the School for Field Studies property. The site was located 15m from the edge of primary rainforest on one side and adjacent to a mosaic of scattered trees, restoration plantings and secondary forest on the other three sides. Each plot had a perch, 3-4m high, cut to standard form from Sarsaparilla (Alphitonia petriei) trees. Each plot also had a watering device placed close to the base of the perch. These were commercially available automatic water dispensers used for poultry set on a 1.5m high base with a perch that allowed birds of different sizes to access water from several angles and for expelled seed to fall to the ground (Figs. 1-3).

Motion-activated cameras (Ranger Compact 2 MP) were installed above each watering device to monitor visits to the water. Apart from a total of 37 days when the cameras were removed for maintenance, the three watering devices were monitored from 22 July 2016 to 13 December 2018 when the trial ended. In the analysis, continuous series of images of one or two birds at a watering device were treated as one visit by that species.

The three plots with a perch and watering device were interspersed with plots that only had a perch or had no structures at all. Apart from within the plots and a narrow access track between them, grass and woody vegetation were not controlled in the surrounding disused pasture.

Figure 3. A Victoria’s Riflebird (Ptiloris victoriae) at a watering device, October 2016.

What we found. Eighty-six visits by three frugivorous bird species were recorded across the three watering devices over the course of the trial. Ninety percent of visits were during the late dry seasons (September-November). One watering device was visited much more often than the others, receiving 70% of all visits. The other two watering devices received 20% and 10% of visits respectively (Table 1).

One bird species, the generalist Lewin’s Honeyeater (Meliphaga lewinii), was by far the most frequent visitor to the watering devices, making up 80% of frugivore visits (Fig. 2). Victoria’s Riflebird (Ptiloris victoriae) was the next most frequent visitor (14% of visits, Fig. 3) and Little Shrikethrush (Colluricincla megarhyncha) was the least frequent visitor (6% of frugivore visits). The only other species that used the watering devices was the Olive-backed Sunbird (Nectarinia jugularis) for which five visits were recorded. All species were recorded drinking from the watering devices. Only the Olive-backed Sunbird could bathe in the small water outlets and were recorded doing so on three occasions.

The watering devices required little maintenance over the 2.5yrs they were deployed. Water was replenished when needed at roughly six-monthly intervals and the water outlets, which collected debris and algae, were cleaned monthly. The devices had no noticeable deterioration at the end of the study.

Table 1. Number of frugivorous bird visits to three watering devices in disused pasture, 22 July 2016 to 13 December 2018.

  1 2 3 Total
Lewin’s Honeyeater Meliphaga lewinii 51 8 10 69
Victoria’s Riflebird Ptiloris victoriae 6 0 6 12
Little Shrikethrush Colluricincla megarhyncha 3 1 1 5
Frugivorous bird visits 60 9 17 86

Conclusions. Our watering devices were only used by three frugivorous bird species, most frequently by the Lewin’s Honeyeater a dietary generalist. Generalist avian frugivores tend to move mainly in more open habitats enhancing the dispersal of pioneer or non-forest trees across the landscape rather than carrying seeds from remnant forest into pasture.

Bird use of the watering devices was highly variable and largely confined to the late dry season when rainfall is low, and temperatures are warm to hot. These are poor conditions for germination and plant growth and likely limit recruitment of dispersed seeds.

Despite these limitations, watering devices are a low-cost intervention that may augment perches and attract frugivorous birds, thereby accelerating forest regeneration. The watering devices deployed in this trial did not collect seed, preserving the potential for seed to be dispersed. They required little maintenance and proved suitable for prolonged outdoor use. Watering devices warrant further investigation. 

Acknowledgements. Thanks to William (Bill) Johnson and John Hall for designing the watering device stand and camera attachment and preparing and maintaining the plots. The School for Field Studies funded the trial.

Contact. Amanda N. D. Freeman. Nature North, PO Box 1536, Atherton, Qld, 4883 Australia. The School for Field Studies, Centre for Rainforest Studies (PO Box 141, Yungaburra, Qld 4884 Australia; Tel: +61 (0) 438 966 773; Email: amandafreeman@naturenorth.com.au).

See also EMR project summary on the preliminary trial of this project: https://site.emrprojectsummaries.org/2016/11/02/a-water-point-design-to-facilitate-seed-dispersal-into-revegetation-or-pasture-sites/

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Posted in Assisted regeneration, Fauna & habitat, Queensland, Rainforest, Techniques & methodology

Waterponding the Marra Creek, NSW rangelands – UPDATE of EMR feature

Posted on 21 October 2019 by | Comments Off on Waterponding the Marra Creek, NSW rangelands – UPDATE of EMR feature

Ray Thompson and Central West Local Land Services

[Update of EMR feature – Thompson, Ray F (2008) Waterponding: Reclamation technique for scalded duplex soils in western New South Wales rangelands. Ecological Management & Restoration 9:3, 170-181. https://onlinelibrary.wiley.com/doi/10.1111/j.1442-8903.2008.00415.x]

Figure 1.  Scalded country with 30cm of sandy loam topsoil swept away by wind after extensive overgrazing. (Photos NSW SCS)

Introduction. Overgrazing of native pastures in the second half of the 19th Century stripped vegetation and led to the wind erosion of sandy topsoil during inevitable dry periods.  By the 1960s, tens of thousands of square kilometres of rangeland sites in western NSW had a legacy of moderate or severely bare or ‘scalded’ lands. This left bare and relatively impermeable clay subsoil which prevents water penetration and is very difficult for plants to colonize (Fig 1.)

Waterponding is the holding of water on the scald in surveyed horseshoe-shaped banks, each covering 0.4 ha. The ponds retain up to 10 cm of water after rain which leaches the soluble salts from the scalded surface. This improves the remaining soil structure, inducing surface cracking, better water penetration and entrapment of wind-blown seed. Consequently, niches are formed for the germination of this seed and recovery of a range of (typically around 15 out of a total of about 30) locally native chenopod (saltbush) grassland species on the sites.

The original 2008 EMR feature described how barren scalds at a range of properties in Marra Creek, near Nyngan in semi-arid NSW were transformed during the 1980s and 1990s into biodiverse native pastures through a technique called ‘waterponding’ developed after five decades of work by consecutive soil conservation officers exploring a range of prototype treatments.  Over time, a wide range of machines have been used to construct waterponding banks including standard road graders (ridged frame and articulated) or similar. Pre-1985 road graders were generally too small to construct banks of sufficient size, which resulted in too many breached banks. Over a 4-year period, the Marra Creek Waterponding Demonstration Program, backed by committed landowners, researched different horsepower road graders, constructing different size banks, winning the dirt from different locations, and evaluating the economics of construction methods. The results showed that the higher-powered articulated road graders exceeding 200 HP proved to be the most economical and efficient for waterpond construction. This type of machine has the power to  form the bank with one pass on the inside of the bank and two passes on the outside, achieving a bank with well over 2 m base width and over 60 cm in height (Fig. 2).

Figure 2. The process of of waterponding including (a) ute-mounted laser levelling to design the waterpond for a particular site, (b) bulldozing the pond walls to the designed levels, (c) rainfall filling the pond to allow deep watering and cracking of the clay subsoil and (d) resulting revegetation within the walls of the pond. (Photos NSW SCS)

Update and the broader program.  Photos and pasture measurements undertaken on ‘Billabong’ Marra Creek NSW, till 2014 show that the waterponding site had increased ground cover (predominantly native species) from 1% in 2005 to 84 % in 2014. After five to seven rainfall years a typical treatment can result in recovery of up to 15 native species from a range of up to 31 species (Table 1). The method in the last 20 years has also included broadcasting seed of some of the more important perennial species of healthy native chenopod grasslands including  Oldman  Saltbush  (Atriplex nummularia), Bladder Saltbush (Atriplex vesicaria) and Mitchell Grass (Astrebla   lappacea) (Fig 3).  Landholders in the Marra Creek district observe a range of fauna frequently on and between the ponds, including Western Grey Kangaroo (Macropus fuliginosus), Red Kangaroo (Macropus rufus), Emu (Dromaius novaehollandiae), Brolga (Grus rubicunda) and the Eastern Bluetongue Lizard (Tiliqua scincoides). A species of Monitor (Varanus sp.) also sometimes traverses the waterponds. Formal monitoring of smaller reptile and invertebrate use of waterponded sites is yet to occur.

Figure 3. Curly Mitchell Grass (Astrebla lappacea) sown on pond banks. (Photo NSW SCS)

Marra Creek was not the first series of waterponding programs in the Nyngan area – nor the last. The outputs of the entire program by 2019 included over 80,000 waterponds laid out and constructed, resulting in 40,000 hectares returned to local native vegetation. A total of 164 properties in the rangelands area are now using waterponding, the majority of landholders in the Marra Creek district and representing an increase from 17 landholders back in 1984 when we first ran the waterponding.

Figure 4. Landholders themselves are teaching the Waterponding technique to other landholders. (Photos NSW SCS)

Economic model of waterponding. The primary driver for land reclamation was not biodiversity conservation but returning the natural capital of rangelands. As such the program has returned a clear profit to the landholders in terms of increased native pastures that can be grazed, improving ecologically sustainable income sources for farming families.

With the reinstatement of vegetation, there have be increases in total stock feed, resulting in an increase in lambing percentages and wool cuts, as well as the ability to carry stock further into prolonged dry periods with overhead cost per head remaining static. Once rehabilitation has been completed, stocking  rates have been raised from zero to one sheep to 1.5 ha. This iseffectively the long-term grazing average for  saltbush pastures in the Nyngan district.

A treatment involving the full design and survey, pond construction and revegetation cost the landholder about $144.00 per hectare. (This includes approximately $25 a hectare for seed.) If the landholder does all the work the cost is reduced to $72/ha. The type of land involved was calculated in 2008 to normally  have  a  resale  value  of  about $365.00 per hectare In its unproductive state.  Scalded land does not contribute to the farm income yet still incurs rates. Investment in rehabilitation, in contrast, improves carrying capacity thus reducing hand-feeding costs, improving lambing percentages and avoiding forced stock sales. This allows landholders to pass the property to the next generation in a far better condition than it has been previously.

Research has found that the scalds store approximately 18.7 t/h of soil organic carbon to a depth of 30 cm. Once the landscape has been restored by waterponding and revegetation, we have found there is a rapid increase in soil organic carbon up to 25 t/ha within five years. The results are indicating that land in the rangelands that has been rehabilitated using waterponds does sequester carbon. This could lead on to waterponding being eligible for a carbon abatement activity and hopefully lead to Carbon Farming Initiative activity for carbon credits.

Figure 5. Australian National University students attending ‘21 years of participation in Rangelands Waterponding’. (Photos NSW SCS)

Potential for further application. After decades of field days and uptake of the methodologies by local graziers (Fig. 4), waterponding now forms part of standard district farming methodologies and landholders are now passing on knowledge to new generations, including through universities (Fig. 5). The methodologies have also been applied at one national park and one Trust For Nature site in Victoria, and are being applied in the Kimberley, with potential for far greater application in desert conservation reserves throughout Australia and the rest of the world (See Fig. 6 and https://justdiggit.org/approach-2/#).

Contact. Kyra Roach, Central West Local Land Services, Nyngan, 2825 Australia. Email: kyra.roach@lls.nsw.gov.au

Figure 6. A total of 79 trainees from 26 Africa countries (including Ghana, Tunisia, Rwanda, Burundi and Djibouti) over a three year period were sponsored by AusAid to study waterponding in Nyngan. Resullting work in African countries is making a big difference to degraded lands particularly in North Sudan and Kenya (Photo NSW SCS)

Table 1. Species found in waterponds after standard revegetation treatments and five to seven rainfall years. The species found by Rhodes (1987b) are still commonly found, with additional species (marked with a diamond +) observed by Ray Thompson. (Plant names are consistent with the New South Wales Herbarium database PlantNet, http://plantnet.rbgsyd.nsw.gov.au/ and  growth forms are consistent with Cunningham et al. (1981) (Exotics are marked with an asterisk)

Scientific name Common name Growth form
Alternanthera denticulata Lesser Joyweed Annual forb
Astrebla lappacea+ Curly Mitchell Grass Perennial grass
Atriplex leptocarpa Slender-fruited Saltbush Perennial subshrub
Atriplex lindleyi+ Eastern Flat Top Saltbush Annual subshrub
Atriplex nummularia+ Oldman Saltbush Perennial shrub
Atriplex pseudocampanulata Mealy Saltbush Annual subshrub
Atriplex semibaccata+ Creeping Saltbush Perennial subshrub
Atriplex spongiosa Pop Saltbush Annual forb
Atriplex vesicaria Bladder Saltbush Perennial subshrub
Centipeda thespidioides Desert Sneezeweed Perennial forb
Chamaesyce drummondii Caustic Weed Annual or short-lived perennial forb
Chloris truncata Windmill Grass Annual or perennial grass
Diplachne fusca Brown Beetle Grass Perennial grass
Eragrostis parviflora Weeping Lovegrass Annual or short-lived perennial grass
Eragrostis setifolia Neverfail Perennial grass
Hordeum leporinum* Barley Grass Annual grass
Hordeum marinum* Sea Barley Annual grass
Maireana pentagona Hairy Bluebush Perennial subshrub
Malacocera tricornis Soft Horns Perennial subshrub
Marsilea drummondii Common Nardoo Perennial forb
Medicago minima* Woolly Bur Medic Annual forb
Medicago polymorpha* Burr Medic Annual forb
Osteocarpum acropterum+ Water Weed Perennial subshrub
Phalaris paradoxa* Paradoxa Grass Annual grass
Pimelea simplex Desert Rice-flower Annual forb
Portulaca oleracea Common Pigweed Annual forb
Salsola kali var. kali Buckbush Annual or biennial forb
Sclerolaena brachyptera Short-winged Copperburr Short-lived perennia
Sclerolaena calcarata+ Red Copperburr Perennial subshrub
Sclerolaena divaricata+ Pale Poverty Bush Perennial subshrub
Sclerolaena muricata Black Roly-poly Short-lived perennial
Sclerolaena trycuspis Streaked Poverty Bush Perennial subshrub
Sporobolus actinocladus Katoora Grass Perennial grass
Sporobolus caroli Fairy Grass Perennial grass
Tragus australianus Small Burr Grass Annual grass
Tripogon loliiformis+ Five Minute Grass Perennial grass

 

 

 

 

 

 

 

 

 

 

 

 

 

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Posted in agricultural lands, arid, Assisted regeneration, carbon storage, Community involvement, Cultural & socio-economic issues & solutions, Ecosystem services, Education & communication, EMR 20th anniversary updates, Environmental watering, Erosion issues & solutions, Fauna & habitat, Grassland/grassy understorey, Integrating ecosystems & industries, New South Wales, Other communities, Planning, monitoring & assessment, semi-arid, Techniques & methodology

Eastern Suburbs Banksia Scrub: is fire the key to restoration? – UPDATE to EMR FEATURE

Posted on 10 October 2019 by | Comments Off on Eastern Suburbs Banksia Scrub: is fire the key to restoration? – UPDATE to EMR FEATURE

Geoff Lambert, and Judy Lambert

[Update to EMR Feature – Geoff Lambert and Judy Lambert (2015) Progress with restoration and management of Eastern Suburbs Banksia Scrub on North Head, Sydney.  Ecological Management & Restoration, 16:2, 95-199. https://onlinelibrary.wiley.com/doi/10.1111/emr.12160]

Key Words. Banksia Scrub, North Head, Critically Endangered Ecological Community, Diversity.

Fig 1. Images of the same location over time, taken from “walk-through” photographic surveys (top to bottom) pre-fire, immediate post-fire and 5-years post-fire. (Photos Geoff Lambert)

Introduction. In the original feature, we reported on a number of projects related to the fire ecology of Eastern Suburbs Banksia Scrub (ESBS), also known as Coastal Sand Mantle Heath (S_HL03), located in conserved areas on North Head, Sydney Australia. Following a Hazard Reduction burn in September 2012, we examined changes in species numbers and diversity and compared these measures with control areas which had been thinned. We fenced one-third of the survey quadrats to test the effects of rabbit herbivory. There had been no fire in this area since 1951.

Twelve months after treatment, burned ESBS had more native plants, greater plant cover, more native species, greater species diversity and fewer weeds than did thinned ESBS (Fig 1). Areas that had been fenced after fire had “superior” attributes to unfenced areas. The results suggested that fire could be used to rejuvenate this heath and that this method produced superior results to thinning, but with a different species mix. Results of either method would be inferior were attempts not made to control predation by rabbits (See 2015 report).

Further works undertaken. In 2015 and 2017 we repeated the surveys, including photographic surveys on the same quadrats. Further Hazard Reduction burns were conducted, which provided an opportunity to repeat the studies reported in the 2015 feature. The study design of the burns was broadly similar to the earlier study, but rabbits were excluded by fencing four large “exclosures” over half the burn site. The pre-fire botanical survey was carried out in 2014, with logistical difficulties delaying the burn until late May 2018. Drought and other factors saw a post-fire survey delayed until October 2019. Photographic surveys of the quadrats have been completed.

Seven cm-resolution, six-weekly, aerial photography of North Head is regularly flown by Nearmap© (Fig 2). We use this photography to monitor the whole of the headland and, in particular, the various burn areas. In order to extrapolate from our quadrat-based sampling (usually 1% of a burn area), the University of Sydney flew 5mm-resolution UAV-based surveys on our behalf, on one of the 2012 burn areas and on the 2018 burn area in November 2017 (Fig 3) .

Apart from the fire studies, the general program of vegetation propagation and management has been continued by the Sydney Harbour Federation Trust and the North Head Sanctuary Foundation. The Australian Wildlife Conservancy has also undertaken a “whole of headland”, quadrat-based vegetation survey as the first stage of its “Ecological Health” rolling program for its sites.

Fig 2. Nearmap© site images (top to bottom) pre-fire, immediate post-fire and 7-years post-fire. (Photos Nearmap)

Further results. The original results suggested that fire could be used advantageously to rejuvenate ESBS and produced superior results to thinning. While subsequent photographic monitoring shows distinct vegetation change (Figs 1 and 2), on-ground monitoring showed that by five years after the fire we could no longer say this with any optimism. In summary:

  • In the immediate fire aftermath, there was vigorous growth of many species
  • Over the ensuing 5 years, plants began to compete for space, with many dropping out
  • Species diversity was high following the fire but then dropped below pre-fire levels
  • Some plants (e.g. Lepidosperma and Persoonia spp.) came to dominate via vegetative spread
  • The reed, Chordifex dimorphus has almost disappeared
  • Tea-trees (Leptospermum spp.) are gradually making a comeback
  • Between 2015 and 2017, ESBS species numbers were outpaced by non-ESBS species, but held their own in terms of ground cover.

The total disappearance of Chordifex (formerly an abundant species on North Head and prominent in the landscape) from fully-burned quadrats was not something that we could have predicted. This species is not in the Fire Response database, although some Restio spp. are known to be killed by fire. This contributes greatly to the visual changes in the landscape. The great proliferation of Lance Leaf Geebung (Persoonia lanceolata) has also changed the landscape amenity (Fig 1, bottom).

To summarise, the 2012 burn has not yet restored ESBS, but has produced a species mix which may or may not recover to a more typical ESBS assemblage with ongoing management over time. Given that the area had not been burned for 60 years, it may be decades before complete restoration.

Our further studies on the use of clearing and thinning on North Head as an alternative to fire (“Asset Protection Zone Programme”), indicates that thinning and planting can produce a vegetation community acceptable for asset protection fire management and potentially nearly as rich as unmanaged post-fire communities (Fig 4). It is necessary to actively manage these sites by removing fire-prone species every two years. In addition, a trial has been started to test whether total trimming of all except protected species to nearly ground level in an APZ, is an option for longer-term management.

Fig 3. “Thinning Experiment” fenced quadrat #3 in July 2019. The quadrat was created in 2013 by removing Coastal Teatree (Leptospermum laevigatum) and Tree Broom Heath (Monotoca elliptica). The experimental design is a test of raking and seeding, with each treatment in the longer rows. All non-endangered species plants were trimmed to 0.25 metres height in mid-2017. (Photo Geoff Lambert)

Lessons learned and future directions. It is too early to say whether we can maintain and/or restore North Head’s ESBS with a single fire. Further fires may be required. A similar conclusion has been drawn by the Centennial Parklands Trust, with its small-scale fire experiments on the York Road site. We need new and better spot- and broad-scale surveys and further burns in other areas on North Head over a longer period. The spring 2019 survey, just completed, offers an opportunity to better assess the notion that fire is beneficial and necessary.

It will be necessary to monitor the effects of future fires on ESBS diversity closely and for much longer than five years. More active management of the post-fire vegetation may be needed, as we have previously discussed in the feature, and as happens at Golf Club sites (also see video) .

The 2012 burn was relatively “cool”. There is some evidence that “hot” burns (such as have been carried out by NSW Fire and Rescue at some Eastern Suburbs golf courses) may produce improved restoration of ESBS. The 2018 burn on North Head was planned as a “hot” burn. This was not completely achieved, but we may be able to compare “hot” and “cool” burn patches within it.

Fig 4. A 2017 UAV image of quadrat 23 five years after the 2012 burn. The image has been rotated to show the quadrat aligned on the UTM grid. The red square shows the rabbit-proof fences; the black square shows the survey quadrat and the blue squares show the four 1×1 metre vegetation plots. The resolution is approximately 5 mm. (Photo University of Sydney Centre for Field Robotics)

Stakeholders. Sydney Harbour Federation Trust, North Head Sanctuary Foundation. Australian Wildlife Conservancy, NSW National Parks and Wildlife Service, Fire & Rescue NSW.

Funding Bodies. Foundation for National Parks & Wildlife [Grant No. 11.47], Sydney Harbour Federation Trust, Australian Wildlife Conservancy.

Contact Information. Dr G.A.Lambert, Secretary, North Head Sanctuary Foundation, (P.O.Box 896, BALGOWLAH 2093, Tel: +61 02 9949 3521, +61 0437 854 025, Email: G.Lambert@iinet.net.au. Web: https://www.northheadsanctuaryfoundation.org.au/

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Posted in Assisted regeneration, Bush regeneration, Fire Ecology & Management, Monitoring, New South Wales, Reserve management, Sclerophyll communities, Techniques & methodology, Threatened species & communities, Urban ecosystems