Category Archives: Weed issues & solutions

Fire as a tool in maintaining diversity and influencing vegetation structure – Grassy Groundcover Restoration Project

Paul Gibson-Roy

Greening Australia’s Grassy Groundcover Restoration Project commenced in 2004 to investigate the feasibility of restoration of grasslands and grassy woodlands (primarily by direct seeding) in the agricultural footprint of Australia. To date the project has achieved the reconstruction of grassy understories in grassland or grassy woodland on near to 100 sites in ex-agricultural land (predominantly across Victoria, but increasingly in southern to central New South Wales and mid-lands Tasmania). Post establishment we use fire in our sites to reduce biomass, particularly to inhibit grass growth which over time become the dominant life form, just like trees can in other communities. Opening the grass canopy allows for the small forbs and sub-dominant grasses to regenerate. Burning in particular can help create these canopy gaps and in a cost-effective way.

Fig 1. Snake Gully CFA burn at Chepstowe.

Fig 1. Snake Gully CFA burn at Chepstowe.

Fig 2. Restored herb-rich grassland on roadside near Wickliffe.

Fig 2. Restored herb-rich grassland on roadside near Wickliffe.

Fig 3. Differential management of Kangaroo Grass at Rokewood Cemetery.

Fig 3. Differential management of Kangaroo Grass at Rokewood Cemetery.

Operational challenges can and often do arise considering sites are located within urban or agricultural footprints where protection of life and property is paramount. This at times prompts us to consider alternative methods of biomass removal such as through grazing (sometimes used as a method for annual weed control) and mowing when burning is deemed inappropriate. These alternative or complimentary biomass reduction methods can also have additional benefits. For example, mowing and producing bales of cut straw, if cut in early spring or autumn, can be used for fodder. This is also the case with grazing. Alternatively, if sites are cut and baled in late spring or summer when grasses contain ripe seed, the hay can be moved and spread at other locations to create a grassland elsewhere.

While the project has carried out various combinations of these approaches at our restored grasslands in recent years, the following list includes a few examples of their use.

  1. Burning at Chepstowe (located to the west of Ballarat, Victoria) to reduce grass biomass and allow forbs to establish and persist. The burn is being conducted by Snake Gully CFA members (Figure 1).
  2. The nationally threatened species – Hoary Sunray (Leucochrysum albicans tricolor) and Button Wrinklewort (Rutidosis leptorrynchoides) were introduced by direct seeding along with many other ground layer species onto a roadside near Wickliffe, Victoria. Following establishment the grassland has been managed with fire by the Wickliffe CFA so that grasses do not dominate and the rare species can recruit and spread. (Figure 2.)
  3. Kangaroo Grass (Themeda triandra) growth has been the focus of differing management techniques within the Rokewood cemetery reserve Victoria (under the Cemetery Trusts grassland management plan). This remnant grassland contains the largest Victorian population of the nationally threatened Button Wrinklewort. To avoid the Kangaroo grass dominating the herb rich areas, it is maintained by fire, whereas in the approaches to the burial area it is kept mown low for function and protection of the memorial infrastructure. (Figure 3).
  4. Similar opening of a restored grassy canopy is achieved at Chatsworth in south western Victoria where a grassland currently dominated by Wallaby Grass (Rytidosperma setaceum) was mown and baled (Figures 4 and 5). This material was used to as fodder by the landholder.
  5. A late autumn burning of herb-rich restored grassland at Hamilton, Victoria, undertaken by the Buckley Swamp CFA (Figure 6).
  6. The aforementioned site at Hamilton taken in the following spring. It shows visitors touring the restoration where Common Everlasting (Chrysocephalum apiculatum) and many other sub-dominant forb species are in full bloom (Figure 7).
  7. Diverse restored grassland located adjacent to a wheat crop at Point Henry, near Geelong, Victoria. This site 16 ha site has been maintained over time by combinations of burning and cutting and baling (Figure 8).
Fig 4. Wallaby grass dominated grassland at Chatsworth pre-baling.

Fig 4. Wallaby grass dominated grassland at Chatsworth pre-baling.

Fig 5. Wallaby grass dominated grassland at Chatsworth post-baling.

Fig 5. Wallaby grass dominated grassland at Chatsworth post-baling.

Fig 6. Buckley Swamp CFA conducting a late autumn burn of restored herb-rich grassland near Hamilton.

Fig 6. Buckley Swamp CFA conducting a late autumn burn of restored herb-rich grassland near Hamilton.

Deciding which method or combination of biomass removal techniques to use, and at what time can be complex and there is no textbook. Good management is about constantly assessing the landscape and prevailing conditions to identify prompts for action. It is also about having the right networks and technical capacity available when required. As a general rule we find that when a site has greater than 70% vegetation cover of the ground surface and dry material is being held above 150 mm, there is enough combustible material to carry a flame. This condition also indicates that that the gaps in the vegetation are starting to close up.

Contact: (Dr) Paul Gibson-Roy. Lead Scientist, Greening Australia.Tel: +61 437591097. Email: PGibson-Roy@greeningaustralia.org.au

[This project summary is a precis of a talk presented to the Nature Conservation Council of NSW’s 10th Biennial Bushfire Conference, ‘Fire and Restoration: Working with Fire for Healthy Lands’ 26-27 May 2015. For full paper see: http://www.nature.org.au/healthy-ecosystems/bushfire-program/conferences/%5D

 Fig 7. Spring and wild flowers are in bloom at Hamilton.


Fig 7. Spring and wild flowers are in bloom at Hamilton.

Fig 8. Species and functionally diverse restored grassland adjoining a wheat crop near Geelong.

Fig 8. Species and functionally diverse restored grassland adjoining a wheat crop near Geelong.

Prescribed burning provides opportunities for site restoration via weed management in the Mount Lofty Ranges, South Australia

Andrew Sheath

Introduction. The purpose of much of the prescribed burning work we do in the Mount Lofty Ranges in South Australia fuel reduction to mitigate the risk of bushfire. But we also do a lot of work, including burning, purely for the purpose of biodiversity conservation. Being so close to Adelaide all of our Parks are highly fragmented and have a strong history of disturbance such as mining and grazing.

Within our team we have a very strong focus on weed control and we do this routinely for all of our burns. There are two reasons we have such a focus on weed management and no longer just go in and burn and walk away. The first is to ensure that the vegetation condition does not deteriorate and the second is to ensure that fuels don’t increase due to woody weeds. In many cases this is leading to improvements in quality of the sites.

Methods. Our burns are done under a prescription which specifies certain weather parameters for which the burn can be carried out safely. Our sites are typically between 5 and 200 hectares, often adjacent to built assets (Fig 1). Mapping both before a burn and 4 years after a burn allows us to monitor progress. We map most of our burns on foot, assessing native vegetation condition, weeds present, their distribution and their cover throughout the proposed burn site. We undertake this with a view to gaining a clear picture of what we’ve got to deal with during the burn and post-burn. Our planning begins 6-18 months prior to a burn to give us plenty of time to carry out works that are often seasonally dependent.

Fig 1: Example of a typical Adelaide Hills conservation area on the urban fringe. Red areas show prescribed burns either completed or in the planning phase.

Fig 1.  Example of a typical Adelaide Hills conservation area on the urban fringe. Red areas show prescribed burns either completed or in the planning phase.

Examples and results to date. In most of our situations pre-burn control greatly increases the efficiency of any post-burn work and overall makes our work easier.

Example 1: Figures 2 and 3, shows a significant reduction in the distribution of Gorse (Ulex europaeus) at an otherwise relatively intact site after the burn, improving the condition of the bush in this area.

Fig 2. Gorse distribution and density pre-burn

Fig 2. Gorse distribution and density pre-burn

Fig 3: Gorse distribution and density 3 years post burn after control work

Fig 3. Gorse distribution and density 3 years post burn after control work

Example 2: Figure 4 shows successful tree heath (Erica arborea) control in an otherwise intact woodland in the Adelaide hills. Six months prior to burning we cut and disturbed the stand of Tree Heath on this site to ensure all the biomass would burn; that we wouldn’t have the adults sitting up high above the flame dropping seed onto burnt ground (which often happens when burning under mild conditions); and, to promote juveniles which would then be burnt and killed during burn. The other benefits of this approach are that it also promotes native germination and makes follow up, post-burn easier.

Fig 4: Erica control site showing before being burnt or cut, after being cut and post burn.

Fig 4: Erica control site showing before being burnt or cut, after being cut and post burn.

Fig 5. Erica post control and pre-burn

Fig 5. Erica post control and pre-burn

Fig 6. Erica post-control and post-burn

Fig 6. Erica post-control and post-burn

Example 3: Figure 5 shows a perched swamp in the Adelaide Hills being thickly invaded by Wonnich (Callystachys lanceolata) from Western Australia. Because of location of the site we were unable to burn the swamp at sufficient intensity to consume the Wonnich. So in this situation we burnt the surrounding area in spring in mild conditions within prescription. We later went back in autumn after we had dropped all of the Wonnich on the ground and we burnt that swamp at a very high intensity and consumed all of the biomass. That promoted mass-germination of the weed. We’re then dealing with one age-class and we can go through and hand weed, spot spray, and re-burn areas to control the germination. Joe Quarmby, Threatened Flora Ecologist, was the mastermind behind this burn and continues to drive follow up control work at the site.

Fig 7. Swamp burnt in drier conditions during autumn.

Fig 7. Swamp burnt in drier conditions during autumn (after surrounding area burnt in more mild conditions in an earlier season).

Follow up control work in swamp.

Fig. 8. Follow up control work in swamp.

Lessons learned. Burning can be a very useful tool for weed management and although no site is ever the same we have been able to use a variety of techniques for certain weeds which greatly increase our efficiency. The key point however is that weed control should be and is routine and needs to be thought about pre-burn.

Acknowledgements. Thanks is extended to Joe Quarmby, Threatened Flora Ecologist.

Contact: Andrew Sheath, Department of Environment Water and Natural Resources – South Australia. Tel: +61 0457 512 032, Email: Andrew.Sheath@sa.gov.au

[This project summary is a precis of a talk presented to the Nature Conservation Council of NSW’s 10th Biennial Bushfire Conference, ‘Fire and Restoration: Working with Fire for Healthy Lands’ 26-27 May 2015. For full paper see: http://www.nature.org.au/healthy-ecosystems/bushfire-program/conferences/%5D

Forested wetland regeneration project, The Gap Road Woodburn, NSW

Julie-Anne Coward

Contract bush regeneration works involving fire and weed management commenced in 2011 in 2.5 ha of endangered ecological coastal floodplain communities at the Cowards’ property on the Gap Road, Woodburn in northern NSW (Fig 1). An area of 7.19 ha of the 10ha property had been recently covenanted for conservation by new owners and 2 small grants were gained to convert the previous grazing property back to forested wetland. Remnant vegetation existed on the property and regrowth was already occurring, although extensive areas were dominated by exotic pasture grasses, particularly >1m high swathes of Setaria (Setaria sphacelata).

Works commenced with spraying of the weed with herbicide and regular follow up spot spraying of weed regrowth. However, because the dead Setaria thatch was taking a long time to break down (and high weed regeneration was likely) a burn was carried out to hasten the recovery responses to fit within the 3 year funding cycle. The works were monitored before and at 6 monthly intervals using 6 (9m2) quadrats in each of hot burn, cool burn and unburnt areas (Fig 1).

Fig 1. Works zones at the Gap Road wetland

Figure 1. Works zones at the Gap Road wetland – mapped in April 2013 where the quadrats were laid out. and data recorded prior to and at 6-monthly intervals after treatment.

Works undertaken. A 2-3m wide firebreak was cut around the burn area and a burn was conducted in dry conditions on Oct 19th 2012 (Fig 2) by the landholders, assisted by Minyumai Green Team and with the local fire brigade on standby. The fire burnt approximately 0.5 ha of the Setaria-dominated area, most of which had been previously sprayed (Fig 2).

Results. A more complete (and presumably hotter) burn was achieved in the sprayed areas (Figs 3 and 4). Setaria and Ragweed germinated prolifically, with a few natives and the site was virtually blanket sprayed with glylphosate. By the second follow up natives had started to regenerate so spot-spraying was used thereafter, taking care to protect the natives. Within 5 months quadrats in the sites that burned hotter achieved over 50% native cover, while the unburnt area achieved only half (25%) that cover. Both areas ultimately achieved similar recovery of natives, but markedly higher spot spraying inputs over longer time frames were needed in the unburnt areas compared to the hotter burn areas.

Over the three year contract, unexpectedly high and prolific regeneration occurred of 35 species of native forbs, sedges and grasses (germinating from buried seed banks) and 7 species trees and shrubs (largely from seed rain) (Fig 5). However, weed germination was also prolific, particularly in unburnt areas, and required at least monthly levels of continual suppression.

fig 2. The burn itself (Oct 17, 2015)

Figure 2. The burn itself (Oct 17, 2015)

Figure 3. Sprayed Setaria prior to the burn.

Figure 3. Sprayed Setaria prior to the burn.

Figure 3. Prolific native groundcover and tree regeneration 2 years after the burn and as a result of consistent spot spraying.

Figure 3. Prolific native groundcover and tree regeneration 2 years after the burn and as a result of consistent spot spraying.

Lessons learned. The proximity of remnant vegetation (within 100m) and intact soil profile was important to the native recovery. At least monthly weed control is essential and can achieve results on its own. However, the project involved substantial volunteer time as well as contract labour – and when labour was insufficient new weed populations formed in the disturbed areas that then required more intensive treatment to overcome. Comparing the demand for weed control in burnt and unburnt areas showed that the feasibility of weed control is very much reduced without the use of fire to flush out weed at the outset.

Acknowledgements: The project is dedicated to the memory of Murray Coward who helped initiate the project. Minyumai Green Team (Daniel Gomes, Justin Gomes, Chris Graves and Andrew Johnston) have kept the project on track over the years, with assistance from Tein McDonald. Thanks is due to the EnviTE team, particularly Virginia Seymour, for their work at the site in the first 18 months. The project is covenanted with the Nature Conservation Trust of NSW (NCT) and received some initial funding from NCT. It subsequently gained a $15K Private Land Conservation Grant (funded by Foundation for National Parks and Wildlife and managed through the NCT) and has now gained a second, similar grant to continue and expand the works.

Contact: Julie-Anne Coward, Gap Road Woodburn. Email: mjcets1@bigpond.com

Re-introducing burning to Themeda Headland Grassland EEC, Narooma, NSW.

Tom Dexter, Jackie Miles, Deb Lenson

Key Words: Fire management, threatened ecosystem, Kangaroo Grass, weed management, Themeda

Introduction: In 2012, Eurobodalla Shire Council commenced a project to preserve local stands of declining Themeda Headland Grassland on Council managed land on three small headlands north of Narooma, NSW. Themeda Grassland on Seacliffs and Coastal Headlands is an Endangered Ecological Community (EEC) that grows on higher fertility soils and is listed under the NSW Threatened Species Conservation Act 1995.

Burning was trialed at two of the three sites to test whether fire could improve the environmental integrity of these sites. This trial has potential implications for the much larger stands of this EEC in various conservation reserves scattered along the NSW coastline as there are many which are not currently actively managed.

The three sites were slashed annually until 2010. While the dominant grass, Kangaroo Grass (Themeda triandra) was still present on all sites, the sites exhibited some decline in Kangaroo Grass cover and vigour, with weed present on all three sites (Fig 1). Slashing had kept the headlands free from shrubs however windrows of slashed grass suppressed Kangaroo Grass and appeared to encourage weed invasion. One of the sites, which was left unburnt for logistic reasons, was initially in worse condition than the other two due to the presence of an old vehicle track and more extensive weed cover particularly from Kikuyu (Pennisetum clandestinum).

The intensity of a burn is likely to vary on a seasonal basis and is dependent on the build-up of dead thatch and the prevailing conditions on the day. There is basis to believe that the traditional aboriginal burning would have taken place in Autumn and would have been a relatively cool burn. The optimum time to burn when considering the constraints of weed invasion is early spring.

Fig 1. Mowing damage at Duesburys Beach headland

Fig 1. Lines of bare ground indicate the location of windrows of dead grass from a history of mowing at Duesburys Beach headland

Works undertaken: Two successive burns were conducted in early spring on 2 of the 3 headlands, in August 2013 and August 2014 (Fig 2). The burn in 2013 was hotter than the burn in 2014 due to a higher build up of Kangaroo Grass thatch prior to the burn.

Follow-up weed control was implemented after the burns as the fire created gaps between the grasses and allowed targeted chemical control minimizing off target damage to Kangaroo Grass and other native species.

Data were collected on three occasions using ten 1 x 1 m quadrats, established along a 50 m transect spaced at 5 m intervals (one of these for each headland). The initial baseline data were recorded in Nov 2012, prior to the spring burns, and in each successive summer (2013/14 and 2014/15) following the burns.

Fig 2. Dalmeny Headlands burn 2015

Fig 2. Typical burn on the headlands

Results to date: The burnt areas (Figs 3 and 4) showed a significant decrease of annual exotic grasses; especially of Quaking Grass (Briza maxima) and Rats Tail Fescue (Vulpia spp.). The burnt areas also showed vigorous Kangaroo Grass growth and moderate seed production of that species. Two native species -Dwarf Milkwort (Polygala japonica) and Matgrass (Hemarthria uncinata Fig 5) not recorded prior to treatment were found after treatment in the quadrats. The most abundant native forbs, Swamp Weed (Selliera radicans) and Indian Pennywort (Centella asiatica) have persisted on the quadrats but not increased (Fig 6). Some exotic forbs – e.g. Yellow Catsear (Hypochaeris radicata) and Scarlet Pimpernel (Anagallis arvensis) have taken advantage of the removal of grass biomass and have also increased, further future analysis will determine whether this increase will impact on the native forbs. Perhaps the most important finding is the Coast Banksia (Banksia integrifolia) seedlings were killed by the fire allowing the sites to remain grassland.

The unburnt headland continues to deteriorate, with ongoing evidence of continued senescense of Kangaroo Grass, no Kangaroo Grass seed production, and exotic plants continuing to replace Kangaroo Grass in parts of the site. Kikuyu is the main exotic species on this site and is responsible for continued suppression of the native components of the grassland. There is also evidence of shrub invasion beginning to occur. It is anticipated that this site will be burnt in spring 2015.

Fig 2. Duesburys Point just after fire, Sept 2013

Fig 3. Duesburys Point just after burning, Sept 2013

Fig 3. Same site 11 months later, Aug 2014

Fig 4. Same site 11 months later, Aug 2014

What we learned: Kangaroo Grass remains vigorous throughout the burnt sites. The results to date show annual burning to be generally beneficial to the herbaceous components and associated grasses of this EEC. There was a higher success of exotic annual grass control in the first year which is most likely attributed to a hotter fire and perhaps timing. The first year also had accumulated multiple years of thatch which may have assisted fire intensity. Supplementary chemical control was effective, particularly when the fire created gaps between the grasses, allowing for better targeted chemical control.

Future directions: So far the results have shown that an August fire followed by the targeted chemical control of exotic grasses has considerable positive influence on the overall environmental integrity of this ecosystem. The annual burning allows the EEC to remain a grassland by killing off Coast Banksia and Coastal Acacia seedlings. It invigorates Kangaroo Grass growth and reduces the biomass of exotic perennial grasses at least in the short term. This again creates an opportunity in the aforementioned targeted chemical control. The herbaceous composition of the headland also remains intact and future analysis will determine whether burning has either a neutral or positive effect on growth. Kikuyu, Paspalum (Paspalum dilitatum) and annual exotic weeds continue to be the main problem. Increased post-burn selective herbicide application or hand weeding and planting of Kangaroo Grass tubestock may help to restore the grassland more rapidly than use of fire with limited weed control alone. Ongoing funding is being sought to continue the works over coming years and achieve further positive future outcomes.

Acknowledgements: The works were undertaken by Eurobodalla Shire Council with funding from the NSW Environmental Trust. Fire assistance from the NSW Rural Fire Service and cultural advice provided by Elders of the Walbunja people.

Contact: Tom Dexter; Environment and Sustainability Project Officer; Eurobodalla Shire Council (PO Box 99 Vulcan St Moruya 2537, Australia. Email: tom.dexter@eurocoast.nsw.gov.au).

Fig 5. Hemarthria uncinata was more evident after fire. (Duesburys Beach headland.)

Fig 5. Hemarthria uncinata was only evident after fire. (Duesburys Beach headland.)

Fig 5. More forbs among the grass after fire at Duesburys Point – e.g. Sellaria radicans

Fig 6. The forb Sellaria radicans persisted  among the grass after fire.

 

Wompoo Gorge Lowland Subtropical Rainforest Restoration Project, Coopers Creek, New South Wales

Key words : Connectivity, Lowland Subtropical Rainforest, Threatened Species

Introduction. Much of the state- and nationally listed Lowland Subtropical Rainforest at Wompoo Gorge, located on Coopers Creek near Rosebank, was partially cleared for pasture early last century. Parts of the cleared forest regenerated naturally with the removal of agricultural activities from the site during the 1940s-50s, but Lantana (Lantana camara) established in large gaps (Fig 1) and prevented any further rainforest regeneration. This weed domination reduced the function of an important habitat linkage between Nightcap and Goonengerry National Parks. Twenty-seven threatened species (10 threatened flora species and 17 vulnerable animal species) have been recorded on the site, which has been identified as a key climate change and wildlife corridor.

In 2009 a program of ecological restoration commenced, guided by the recommendations of the Wompoo Gorge (South) Ecological Restoration Plan (updated in 2013). The aim of the restoration works was to control Lantana and other weeds, restoring the integrity of the rainforest and helping to supporting the region’s exceptional biodiversity.

A monitoring program was established on site prior to commencement of works. This included eight transects and photopoints. Structural and floristic information has been collated and photos taken prior to the commencement of works, and subsequently over the course of restoration work. Data have been entered into then MERV (Monitoring and Evaluation of the Restoration of Vegetation) database and used to produce reports.

Figure 1. (map) Lantana cover prior to restoration. By 2014 very little lantana remained with regenerating rainforest taking the place of weeds.

Figure 1. (map) Lantana cover prior to restoration. By 2014 very little lantana remained with regenerating rainforest taking the place of weeds.

Works undertaken: Lantana has been controlled by a range of methods (Figs 2-4) including: mechanically with a tractor; spraying with a splatter gun; over-spraying dense, less accessible areas; hand weeding with brush hooks and loppers; and, cut/scrape and paint of scattered Lantana among remnant vegetation. Other less dominant weeds have been controlled to facilitate replacement of Lantana with regenerating rainforest. Follow-up work includes flattening down dead Lantana, spot spraying and hand weeding. No planting has been undertaken but fruit from native plants on site has been collected and spread throughout regeneration areas.

Figure 2. September 2009: Prior to lantana control

Figure 2. September 2009: Prior to lantana control

Figure 3.  17 September 2009: Tractor crushes down lantana

Figure 3. 17 September 2009: Tractor crushes down lantana

Figure 4. 21 October 2009: Second tractor run slashing lantana

Figure 4. 21 October 2009: Second tractor run slashing lantana

Results: Lantana has been virtually eliminated from extensive areas and vigorous regeneration of a high diversity of species has occurred (Figs 5-6). Common regenerating species include: Poison Peach (Trema aspera), Red Cedar (Toona ciliata), Giant Stinging Tree (Dendrocnide excelsa), Tamarind (Diploglottis australis), Sandpaper Figs (Ficus coronata) White Cedar (Melia azedarach) Bangalow Palm (Archontophoenix cunninghamiana), Brown Kurrajong (Commersonia bartramia), Pencil Cedar (Polyscias murrayi), Celerywood (P. elegans), Quandong (Elaeocarpus grandis) , Black Bean (Castanosperma australis), Sally Wattle (Acacia melanoxylon). Groundcovers included Soft Bracken Fern (Calochlaena dubia), Cunjevoi (Alocasia brisbanensis) Juncus (Juncus sp.), Cyperus (Cyperus spp.) and Basket Grass (Oplismenus aemulus). A range of later stage rainforest species have also germinated including Hairy Walnut (Endiandra pubens), Maiden’s Blush (Sloanea australis) and White Bolly Gum (Neolitsea dealbata).

Figure 5. ‘’Oct 2010: Resilient native regeneration in tractor cleared area

Figure 5. Oct 2010: Resilient native regeneration in tractor cleared area

Figure 6. May 2014: Natives have replaced lantana throughout cleared area

Figure 6. May 2014: Natives have replaced Lantana throughout cleared area

What we have learned. Wompoo Gorge has proven to be a highly resilient site, located as it is between two major sources of propagules. The site’s unique location, resilience and beauty has made it an ideal site to educate and inspire the community to restore rainforest Field days held on site have assisted in raising regional awareness of the value of the Lowland Rainforest EEC, the habitat it provides and of the degrading impacts of weeds. Various weed control techniques have also been discussed and demonstrated. Involving Green Army participants alongside professional regenerators has helped Green Army participants gaining valuable knowledge, skills and training in ecological restoration.

In 2014 NSW National Parks and Wildlife Service acquired the property realising the goal of former property owner Dailan Pugh to protect the property in perpetuity for the benefit of conserving native species and for future generations.

Acknowledgements: The project has received funding from the NSW Environmental Trust’s Restoration and Rehabilitation program. Additional funding has been invested through the former Northern Rivers Catchment Management Authority, the Great Eastern Ranges Initiative and a Raymond Borland Landcare grant. In 2015 Green Army teams have commenced working on site, alongside professional bush regenerators, undertaking additional and complimentary restoration works.

Contact: Paul O’Connor, Technical Manager, EnviTE Environment, 56 Carrington Street (P.O.Box 1124) Lismore  2480 Australia.

Tel: +61 2 6627 2841 Mob: + 61 427 014 692. Email: paulo@envite.org.au

 

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

Alan Lane

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

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

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

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

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

Figure 1: Notched weir diverting water towards sedimentation pond.

Figure 2: Sedimentation pond

Figure 2: Sedimentation pond

Works carried out:

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

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

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

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

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

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

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

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

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

 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Reconstructing Western Sydney Grassy Woodland Understorey at Hoxton Park, Sydney, NSW

By Christopher Brogan

Purpose of the project. Endeavour Energy sought to restore a small highly disturbed Cumberland Plain Woodland bushland remnant at the West Liverpool Zone Substation at Hoxton Park, to offset 12 native trees removed to facilitate construction works at their electricity substation.

Condition of the site. The Cumberland Plain Woodland remnant was very small (approx.0 3.ha) and contained relatively healthy examples of four native trees (Grey Ironbark Eucalyptus crebra, Grey Box E. moluccana , Forest Red Gum E. tereticornis and some Paperbark Melaleuca decora). However, the native shrub and ground layer was generally absent and the soil surface was highly compacted with a low organic matter content. This was due to historic clearing for agriculture, recent clearing for the installation of electrical infrastructure and the fact that a layer of coarse fill material and asphalt had been deposited over the topsoil in some areas (probably for car parking).

Goals. As we found fragments of 3 grasses and 6 forbs remaining on site, our goals were to protect and enhance all remaining plants by ecologically sensitive weed control and planting of missing species from the Cumberland Plain Woodland community.

We had 24 months to achieve the revegetation, with performance criteria being: a survival rate of >80%; a reduction in the percentage cover weed to < 5%; and, an increase in percentage cover of the herbaceous layer to 67% – 100%.

Fig 1. Weed control included cut stump poisoning of woody weeds and high volume herbicide spraying of invasive perennial grasses.

Fig 1. Weed control included cut stump poisoning of woody weeds and high volume herbicide spraying of invasive perennial grasses. (Photo C Brogan)

Around 260 cubic metres of recycled wood waste was used to mulch to a depth of 100mm over 2,600 square metres.

Around 260 cubic metres of recycled wood waste was used to mulch to a depth of 100mm over 2,600 square metres.(Photo C.Brogan)

What we did. We identified two zones on site: Zone 1 – with capacity for assisted regeneration; and Zone 2 – without capacity for assisted regeneration. Zone 1 was treated using standard bush regeneration techniques – i.e. removal of weed to facilitate natural regeneration. Zone 2 treatments included: weed control, mulching with recycled wood waste (2,600m2 x 100mm deep); planting with 9,100 native tubestock (3-4 plants /1m2) raised from Western Sydney seed; and watering throughout the first month.

After some assisted natural regeneration and planting 9,100 native tubestock (raised from Western Sydney seed) a strong cover of native understorey was reinstated.

After some assisted natural regeneration and planting 9,100 native tubestock (raised from Western Sydney seed) a strong cover of native understorey was reinstated. (Photo. C Brogan)

The Presentation Title

Same part of the site taken before and after treatment.

Same part of the site taken before and after treatment. (C Brogan)

What advice can we offer?

  • Always check your project site to identify any fragments of native species which may be present and protect them during weed control works, particularly when spraying herbicide.
  • Use good quality tubestock of the appropriate provenance and budget for a seed collection program if the project timetable allows.
  • Never underestimate the need to water tubestock during hot months and allocate sufficient resources to watering.

Contact: Christopher Brogan, Earth Repair and Restoration Pty Ltd, PO Box 232 Panania NSW 2213. Tel: +61 (0)2 9774 3200 Email: chris@earthrepair.com.au; Web: www.earthrepair.com.au

Acknowledgement. This is summarised from a talk first presented to the symposium ‘Rebuilding Ecosystems: What are the Principles?’ Teachers’ Federation Conference Centre, November 13th, 2014, Australian Association of Bush Regenerators (AABR).

 

 

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

Alan Lane

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Plant communities of seasonal clay-based wetlands of south-west Australia: weeds, fire and regeneration

Kate Brown and Grazyna Paczkowska

Key words: regeneration, fire, seasonal wetlands

 While the majority of seasonal wetlands in south-west Australia are connected to regional ground water, some found on clay substrates rely solely on rainwater to fill. These seasonal clay-based wetlands fill with winter rains and are characterised by temporally overlapping suites of annual and perennial herbs that flower and set seed as the wetlands dry through spring. Over summer the clay substrates dry to impervious pans. The seasonal clay-based wetlands of south-west Australia comprise a flora of over 600 species, of which at least 50% are annual or perennial herbs, 16 occur only on the clay-pans and many are rare or restricted.

These ecological communities are amongst the most threatened in Western Australia and have recently been listed under the Commonwealth Environmental Protection and Biodiversity Conservation Act as critically endangered. Over 90% have been cleared for agriculture and urban development and weed invasion is a major threat to those that remain. South African geophytes are serious weeds within these communities and Watsonia (Watsonia meriana var. bulbillifera) in particular can form dense monocultures and displace the herbaceous understorey.

Watsonia invading  a seasonal clay-based wetland

Watsonia invading a seasonal clay-based wetland

Regeneration following weed control and fire.  We investigated the capacity of the plant community of such a wetland to regenerate following removal of Watsonia, and the role of fire in the restoration process.

 Our study site, Meelon Nature Reserve, is a remnant clay-based wetland on the eastern side of the Swan Coastal Plain 200 km south of Perth. A series of transects were established in August 2005 and regeneration of plant community following Watsonia control and then unplanned fire was monitored until September 2011 (Table 1).

 Table 1: Six years of monitoring regeneration of a seasonal wetland at Meelon Nature Reserve

August 2005 Thirty 1m x 1m  quadrats established along five 30m transects in the wetlands where Watsonia was estimated to average greater that 75% cover.
September 2005 Cover ( modified Braun Blaquet) recorded for all native and introduced taxa and then Watsonia treated with the herbicide 2-2DPA (10g/L) + the penentrant Pulse® (2.5 mL/L).
September 2006 Cover recorded for all native and introduced taxa and then Watsonia treatment reapplied.
February 2007 Unplanned wild fire burnt across the study site.
September 2007  each year until September 2011 Cover recorded for all native and introduced taxa and then any Watsonia treated.

Analysis of similarity (ANOSIM) was undertaken to determine if there was significant change in species cover and composition from before Watsonia control to six years following the initial treatment. A  SIMPER analysis was used to ascertain the contribution of each species to any changes between monitoring years (Clarke & Gorley 2006).

Results. In the first year of the control program, a 97% reduction in the cover of Watsonia was recorded, but was associated with no significant change in the diversity or abundance of native flora. In February 2007, 18 months after the initial control program, an unplanned summer wildfire burnt through the reserve. In September 2007 monitoring revealed a significant increase in cover and diversity of native species in the treatment areas. Some species such as the Dichopogon preissii had not been recorded before the fire, others, such as the native sedges, Cyathochaeta avenacea and Chorizandra enodis increased greatly in cover following the fire. At the same time there was no resprouting of Watsonia or recruitment from cormels or seed.

Six years after the initial treatment the native sedges and rushes continue to increase in cover, the dominant native shrub Viminaria juncea is increasing, Eucalyptus wandoo seedlings are recruiting into the site and native grasses and geophytes are increasing in cover. The indications are that plant communities of the seasonal clay-based wetlands of south-west Australia have the capacity to recover following major weed invasion and that fire can play a role in the restoration process.

Table 2. Species that contributed to 90% of the significant change in cover and composition of species between 2005 and 2011.

 

2005

2011

Species

Average abundance (% cover)

Average abundance (% cover)

Cyathochaeta avenacea

10.0

23.5

Chorizandra enodis

2.3

15.7

Viminaria juncea

2.1

15.4

Caesia micrantha

2.6

2.7

Briza sp. Meelon

3.1

2.0

Eucalyptus wandoo

0.0

3.0

Austrodanthonia acerosa

0.4

1.8

Hypoxis occidentalis

0.0

1.9

Lepidosperma sp. WT2Q5 Meelon

0.1

1.3

Meeboldina sp. MU3 Meelon 2011

0.2

1.4

Dichopogon preissii

0.0

1.3

Drosera rosulata

1.5

0.2

Contact: Kate Brown, Ecologist, Swan Region. Department of Environment and Conservation, PO Box, 1167 Bentley Delivery Centre, WA, 6983. Email: kate.brown@dec.wa.gov.au

Chorizandra enodis

Chorizandra enodis

Dichopogon preissii

Dichopogon preissii

Hypoxis occidentalis

Hypoxis occidentalis

Macquarie University – Turpentine/Ironbark forest Regeneration

John Macris 

Key words: Bush Regeneration, Privets, Pittosporum, in-situ conservation.

Less than 5% of the original extent of Turpentine/Ironbark forest of the Sydney Basin Bioregion remains and so this forest type is listed is listed as critically endangered under the Commonwealth EPBC Act. Weed management and rehabilitation of remnants are priority conservation actions under the Act.

A 3.5 ha remnant of Turpentine/Ironbark forest located on the Macquarie University Campus has been the focus of a bush regeneration program that commenced in 2010.  Prior to the works, the site was variable in condition, with a core area near a watercourse having relatively high species diversity including Blackthorn (Bursaria spinosa) and the rare shrub Epacris purpurascens, while edges of this area contained a diversity of weed species.  An upslope area was more highly disturbed as it had been used as a breeding enclosure for research into rare rock wallabies until around 2005.

Works to date. Commencing in Autumn 2010, contract bush regeneration works included culling of the over-represented native Sweet Pittosporum (Pittosporum undulatum) in the core area, and removal of invasive weeds, principally a dense mid-story of the woody weeds Large-leaved Privet (Ligustrum lucidum) and Small-leaved Privet (L. sinense) throughout the treatment area.  Any large Privet logs were retained as habitat. Pampas Grass was removed from around the perimeter and, in a few places, Lantana  (Lantana camara) was also removed, although some has been retained as an interim small bird habitat in a few locations. Follow up work has mainly focused on a range of herbaceous weeds including Ehrhardta (Ehrhardta erecta), and gradual exhaustion from the seed bank of the problem woody weed species.

Results Prior to works, we estimated that about 10% of remnant was in relatively good condition.  About 2.5 years on, we now estimate that about 15% – 20% of the area is now in a resilient condition. Native species regenerating include a range of native grasses and forbs including Blady Grass (Imperata cylindrica), Basket Grass (Oplismenus aemulus), Weeping Grass (Microlaena stipoides), Tufted Hedgehog Grass (Echinopogon caespitosus),Blue Flax Lily (Dianella caerulea), Plume Grass (Dichelachne sp.), Finger Grass (Digitaria parviflora) Bordered Panic Grass (Entolasia marginata), Pastel Flower (Pseuderanthemum variabile) and Kidney Weed (Dichondra repens). Tree saplings including Turpentine (Syncarpia glomulifera) and Smooth-barked Apple (Angophora costata) have been uncovered and are developing in height. The colonizing shrub Kangaroo Apple Solanum aviculare has rapidly developed a rudimentary native mid story in the areas cleared of dense Privet.

Woody weed domination of the understorey before the works commenced

Same view 2years later (2012) showing ground stratum regeneration

Lessons learned. To create a robust weed buffer to the regeneration area, we decided it was important to start work in upslope areas, even though they were disturbed by the previous animal research enclosure (e.g. artificial soil profiles).  Due to same competing uses, such areas have been challenging stablise against weed resurgence, but a management edge is being established gradually.

Acknowledgements.  Sixty per cent of the first 15 months funding for the project was provided by Sydney Metropolitan CMA through their Saving Sydney’s Biodiversity Program with the rest covered by the University.  Subsequent work has been funded under Macquarie University’s Biodiversity restoration programs. Warren Jack from the contractor Sydney Bush Regeneration Company contributed much of the above species list of ground layer regeneration.

Contact: John Macris, Macquarie University. john.macris@mq.edu.au Tel: +61 (0)2 9850 4103