The Bitou Bush Threat Abatament Plan (Bitou TAP) is being implemented at over 100 sites across coastal New South Wales. The case studies below provide a flavour of what is being done to save at-risk native species at some Bitou TAP sites. Case studies of where the TAP is being implemented throughout NSW include:
Cosy Corner, Cape Byron State Conservation Area
Site information
Cosy Corner is located west of Tallow Beach within Cape Byron State Conservation Area on the North Coast of NSW. The 10-hectare site has high ecological significance due to the presence of several threatened plant species and an endangered ecological community. The site is important to the Indigenous people of the area and they are actively involved in its management. Cosy Corner was listed as the second highest priority site under the TAP.
The bitou bush problem
Bitou bush was planted in the broader area to stabilise the dune complex following sand mining in the 1960s, mineral sand extraction in the 1930s and gold mining in the 1880s. By the 1990s, bitou bush had invaded the dunes and littoral rainforest and was damaging a suite of native species and ecological communities. For example, large ‘climbing’ bitou bush plants were present in the hind dune communities, and the littoral rainforest was under serious long-term threat because recruitment was being prevented.
Native species threatened by bitou bush invasion
Over 150 native plant and 50 weed species have been recorded on the Cosy Corner site. The high priority biodiversity and threatened species at risk from bitou bush invasion includes Acianthus amplexicaulis, Acronychia littoralis, Archidendron hendersonii, Cordyline congesta, Cryptocarya foetida, Xylosma terra-reginae and an endangered ecological community, Littoral Rainforest.
Collaborative action
The site is part of the National Parks and Wildlife (NPWS) estate, which is managed by Cape Byron Trust. The Trust is a consortium of the Indigenous community (Arakwal people of Byron Bay), NPWS, Byron Shire Council and community representatives. The site is also a demonstration site for monitoring the Bitou TAP.
Control and restoration activities
While implementation of the Bitou TAP commenced in early 2007, the initial control program began in 2005. Rapid and broad scale removal of adult bitou bush plants was the specific aim of the control program, based on the potential for significant native regeneration during the site assessment. A combination of spot spraying using a knapsack sprayer and overspraying using a vehicle-mounted spray rig achieved initial control over the whole site.
A thorough annual monitoring program consisting of four transects with five quadrats each is used to monitor the control of bitou bush and recovery of native species.
Interim results
The plant communities present have responded positively to the broad-scale bitou bush control program implemented. Large areas of the foredune have been or are currently being rapidly recolonised by Coastal Wattle (Acacia longifolia subsp. sophorae). Many Littoral Rainforest species, such as Acronychia imperforata, Cryptocarya foetida, Cryptocarya triplinervis var. triplinervis and Cupaniopsis anacardioides, have begun to grow back on the hind dune and foredune habitats they are thought to have occupied prior to bitou bush invasion. There are now no known mature bitou bush plants within the 10-ha management area. While control led to significant bitou bush germination from the seedbank, the follow-up regime should prevent these seedlings establishing.
Summary
Given the level and speed of native species recovery, it is estimated that a native canopy will be established by the end of 2010, which will reduce the potential for bitou bush to re-invade. This outcome is based on a concerted targeted control program at a site with capacity for significant natural regeneration.
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Before bitou bush control at Cosy Corner | | After initial and follow up bitou bush control at Cosy
Corner |
Bundjalung National Park
Site information
Covering an area of over 17,000 hectares on the North Coast of NSW, Bundjalung National Park stretches from the Evans River south along the coast to the Clarence River. The park is home to a diverse range of vegetation types, from subtropical communities at the southern end of their range, to coastal communities, as well as many temperate species. The park also contains sites and places of significance to local Aboriginal communities and the remains of World War II defence activities.
The bitou bush problem
Surveys in 2001 revealed that approximately 28 kilometres of the frontal dune system was moderately to heavily infested with bitou bush. In addition, bitou bush was a serious problem in the hind dune system and vegetation communities. A large number of other weeds are also present in the park, including lantana (Lantana camara), asparagus fern (Asparagus aethiopicus), madeira vine (Anredera cordifolia), prickly pear (Opuntia sp.), yellow cassia (Senna pendula var. glabrata) and coastal morning glory (Ipomoea cairica).
Native species threatened by bitou bush invasion
The Bitou TAP identified several high priority species in Bundjalung NP, including Pultenaea maritime, Stackhousia spathulata, Ischaemum triticeum, Gleichenia mendellii and Vigna marina. The park also hosts a number of high priority ecological communities, including Themeda Grassland on Seacliffs and Coastal Headlands, Coastal Banksia Woodlands (dominated by Banksia integrifolia), Littoral Rainforest, Coastal Sand Dune Complex (dominated by Acacia longifolia subsp. sophorae) and Frontal Dune Vegetation Complex.
A site assessment revealed that bitou bush was having a medium to high impact on these high priority species and communities, but that most were still in a condition capable of regeneration if bitou bush were removed. As control was also achievable at the site it was given a high priority in the Bitou TAP, based on the likelihood of success.
Collaborative action
Bundjalung National Park is managed by NPWS, who liaises and consults regularly with the Bandjalang Native Title Claimants on management issues, including bitou bush control and native species recovery. The Department of Defence (DoD) manages a weapons range within Bundjalung National Park. The DoD supports and provides operational assistance with bitou bush control across the range. Environmental officers with the DoD are also active participants in the project.
In addition, the Black Rocks Community Dune Care group also works regularly on the site to control bitou bush and restore the native vegetation communities, supported by trained professionals. Positive cooperation exists with other natural area management neighbours, particularly the Dirrawong Reserve Trust that abuts the park to the north.
Control and restoration activities
There was a long history of weed control in Bundjalung prior to the Bitou TAP, including aerial spraying, ground spraying and bush regeneration. These programs were focused on protecting and regenerating the dunal communities, rather than individual species, particularly Littoral Rainforest and Coastal Banksia-dominated communities. Since completion of the Bitou TAP in 2006, the control program has shifted focus to protecting priority species.
Since 2002, the responses of native species, bitou bush and other weed species to control measures as well as unplanned fire events (large areas of the park were burnt in 2001 and again in 2007) are monitored every 6-12 months using 64 (4 x 4-metre) quadrats spread out along the length of the park. Within each quadrat, the floristics, species crown cover, vegetation height, seedling density and seedling height are recorded.
Interim results
The control program has resulted in a 90% decline in the cover of bitou bush, with a corresponding increase in the cover of many native species. For example, coastal wattle (Acacia longifolia subsp. sophorae) has shown an overall increase in cover from 3 to >30%, Coastal Banksia (Banksia integrifolia) has increased from approximately 4 to >13 % cover, and Zoysia macrantha, a native grass, has increased its cover from <1 to >11%. More recently increases in some of the other species identified in the TAP at risk from bitou bush, such as Cupaniopsis anacardioides and Acronychia imperforata, have been observed. Littoral rainforest burnt by wildfire will take many decades to recover.
Summary
While the control of bitou bush at Bundjalung began prior to the completion of the TAP, and positive control and restoration outcomes were achieved, the TAP has helped to focus these efforts towards the species most at risk. The results of this control are very promising.
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Before bitou bush control at Bundjalung National Park | | Aerial view of Bundjalung National Park after bitou
bush control |
Big Nobby, Crescent Head
Site information
Big Nobby is located east of Crescent Head village in Kempsey Shire on the Mid-North Coast of NSW. Its location and height offer spectacular views that attract visitors and residents, but Big Nobby’s scenic value had been degraded by weeds. The 25 hectare site also has high ecological significance due to the presence of several threatened plant species and an endangered ecological community. The site is a management challenge because of cliff faces and steep slopes on the headland, and care is necessary to minimise erosion. The site was listed as a high priority for control in the Bitou TAP.
The bitou bush problem
Bitou bush invaded the headland after being introduced to the Mid-North Coast to stabilise dunes that were sand mined in the 1960s. By the 1990s, bitou bush was present on cliffs and headlands of Kempsey Shire, damaging native species and ecological communities. Big Nobby was suffering from a heavy infestation of bitou as well as invasion by Lantana, Mother of Millions, and exotic grasses.
Native species threatened by bitou bush invasion
Much of the headland is covered by the endangered ecological community: Themeda Grassland on Seacliffs and Coastal Headlands. This community is also habitat for a number of rare or threatened species. Threatened species present include Pultenaea maritima and Thesium australe; priority biodiversity identified in the TAP present include Acalypha nemorum, Pandanus tectorius var australianus, Plectranthus cremnus (ROTAP), Stackhousia spathulata and Viminaria juncea (prostrate form). Other species present include Casuarina equisetifolia and a significant community of Allocasuarina littoralis.
Collaborative action
Kempsey Shire Council manages the site and employs contractors to control weeds threatening biodiversity. The Council implements the Bitou TAP at the site in partnership with the Mid North Coast Weeds Advisory Committee and the Northern Rivers CMA. The wider community has been made aware of the Bitou TAP project through education events with partners such as WetlandCare Australia.
Control and restoration activities
The headland had been spot sprayed since 2005 to reduce the density of bitou and lantana infestations. In April 2007, implementation of the Bitou TAP began through preparation of a site-specific management plan, upon approval this plan was then implemented on the ground. Stage 1 reduced bitou infestation in the immediate vicinity of the threatened species, then in Stage 2 bitou control was extended so that the threatened species could expand. Where bitou was difficult to access, or in large thickets, herbicide application with a splatter gun gave the best results.
Progress has been monitored through the use of photopoints at six-monthly intervals.
Interim results
Regeneration is continuing, with the numbers and condition of threatened plant species improving. In the priority areas, only minimal weed control by hand removal of bitou seedlings is now required. Because of this, weed control works are being extended to include other parts of the headland. The intrusion of coastal wattle into the Themeda Grassland community is also being monitored. Knowledge of threatened plant species and plant communities has increased, along with awareness of the threat to biodiversity posed by weeds.
Summary
Implementing the Bitou TAP has ensured that bitou control efforts were targeted and staged, and led to the recovery of the native biodiversity at risk. Native plants at risk, and an endangered ecological community, are now recovering from bitou invasion. For the community there is the added benefit that a site highly valued for its appearance, has been restored.
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Bitou bush regrowth in Themeda Grasslands
Endangered Ecological Community (EEC) | | Themeda Grassland EEC and the steep terrain on the seaward
side of Big Nobby at Crescent Head |
Site information
The Yacaaba Peninsula is a 2km long sand spit on the north eastern side of Port Stephens on the Mid North Coast of NSW. The peninsula is a popular recreation area for four-wheel driving (4WD), fishing, swimming, and bushwalking. A diverse range of plant species and vegetation communities are present on the site, several of which are not represented in the surrounding National Parks or reserves. The peninsula is also an important cultural site for the local Aboriginal people, the Worimi, and a number of significant cultural sites on the peninsula are testament to their long-term association with the area.
The bitou bush problem
It is suspected that bitou bush was introduced to the area following sand mining in the 1950s and 1960s. Since its introduction, bitou bush has spread throughout the peninsula, where it out-competes native species and forms large hummocks that promote sand blowouts. Four wheel driving between the bitou bush hummocks exacerbate the blowouts, which in turn promotes sand erosion. The bitou bush, four-wheel driving, and sand erosion all threaten sensitive vegetation and sacred Aboriginal sites.
Native species threatened by bitou bush invasion
High priority species found on the peninsula include Stackhousia spathulata and Senecio spathulatus. Chamaesyce psammogeton, one of the species at greatest risk from bitou bush, is known from an adjacent TAP site and is suspected to also occur on the peninsula. Several high priority ecological communities (ECs) are also found on the peninsula, including Littoral Rainforest, Coastal Banksia Woodland, Frontal Dune Vegetation Complex, Coastal Scrub (dominated by Leptospermum laevigatum/Acacia longifolia subsp. sophorae), and Spinifex sericeus dominated Dune Grasslands.
The priority species and ECs found on the peninsula are constrained to coastal habitats, and bitou is likely to impact across their entire distribution. The species' short-lived seed bank and limited seed dispersal capability also threatens their ability to withstand long-term bitou invasion.
Collaborative action
Bitou control on the peninsula is occurring as a close collaborative partnership between Great Lakes Council, Worimi and Karuah Local Aboriginal Lands Council, Northern Aboriginal Heritage Board, National Parks and Wildlife Service (Great Lakes Area), Conservation Volunteers Australia (CVA), Hunter-Central Rivers Catchment Management Authority, Taree Indigenous Development and the Mid North Coast Weeds Advisory Committee.
Integral to the success of the bitou control on the headland is the employment and training of members of the local Aboriginal community. This group is employed through Conservation Volunteers Australia (CVA) and is undertaking a 6 month Conservation Land Management Certificate II (TAFE certified). They conduct much of the on-ground works, and it is hoped that they will continue to work on the site as trained regenerators in the area.
Control and restoration activities
Prior to the development of the TAP, control of bitou and other weeds occurred sporadically across the peninsula. Under the bitou TAP, these control works have been focussed on high priority areas. The first stage of control works under the TAP used fences to restrict and redirect 4WD movement on the peninsula away from particularly sensitive and degraded areas. The second stage has expanded control to specifically target bitou threatening the Littoral Rainforest remnants at the north and southern ends of the peninsula. The cut-and-paint technique was used due to the sensitivity of the vegetation to herbicides, with the cut material being used as a mulch to promote Littoral Rainforest regeneration. Hand removal of bitou and other weeds supplements chemical control techniques in highly sensitive areas.
Works are now focusing on removing bitou from around Stackhousia spathulata plants. This necessitates hand weeding of bitou from above Stackhousia plants, and backpack spraying of bitou adjacent to Stackhousia populations.
The success of bitou control and the regeneration of native species are monitored twice a year using photopoints and quadrats.
Interim results
Control works in the three most sensitive areas of the headland (from six areas) have resulted in an 80% reduction in bitou cover. Much of the control has focused on the Littoral Rainforest remnants, which are naturally slow to respond, however photopoints and quadrats have detected an increase in the germination of native species. Control in these areas is continuing, with more of an emphasis on secondary weeds such as asparagus fern (Asparagus aethiopicus), that are also emerging following bitou control.
Summary
The control of bitou bush on Yacaaba Peninsula will dramatically improve the natural and cultural features of the site. Native species are already responding to the removal of bitou, and with the control of secondary weeds, they are predicted to continue to flourish.
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Bitou bush growing in hummock form in the
habitat of the species at risk | | Fencing erected to prevent 4WD movement in the habitat of the species at risk |
Wamberal Lagoon Nature Reserve
Site information
Spoon Bay is located at Forresters Beach, within Wamberal Lagoon Nature Reserve (the Reserve) on the Central Coast of NSW. The five hectare site contains the threatened species Chamaesyce psammogeton, Senecio spathulatus and Syzygium paniculatum, as well as Littoral Rainforest, an endangered ecological community. The site also has an active community group involved in the rehabilitation. The Reserve was listed as the seventh highest priority site under the Bitou TAP.
The bitou bush problem
Bitou bush has invaded the fore- and hinddunes as well as the headlands at Wamberal Lagoon, replacing native vegetation. Bitou bush has been spread by birds and foxes.
Native species threatened by bitou bush invasion
Over 60 species of introduced plants have been recorded in the Reserve, including Asparagus asparagoides, Polygala myrtifolia, Ochna serrulata, Senna pendula var. glabrata and Lantana camara. Bitou bush infestations are thickest on the foredunes, impacting on native plants, in particular Cupaniopsis anacardioides, Syzygium paniculatum, Banksia integrifolia, Leptospermum laevigatum, Correa reflexa, Acacia longifolia subsp. sophorae, Monotoca elliptica, Senecio spathulatus, Stackhousia spathulata and Westringia fruticosa.
Collaborative action
A community volunteer group has been working on site since 2003, using cut and paint and hand pull methods. Four Green corps teams, natural resource management students from Newcastle University and NPWS staff have also worked on site, undertaking primary and secondary weed removal.
Control and restoration activities
Implementation of the Bitou TAP began on site in 2007 - two bush regeneration companies were employed to work along the dune. Regenerators cut tracks through the bitou and sprayed with splatter guns using small volumes of high concentration glyphosate. Bitou was also cut and painted and hand pulled. NPWS staff have sprayed along the dunes using a vehicle-mounted spray unit. Secondary and maintenance weeding has followed up primary work since the initial control.
Six twenty square metre nested quadrats have been established over the site to monitor bitou bush control and native species recovery.
Interim results
The site had a weed density of >60 % at the start of the project, which has since been reduced to <10% for the majority of the site. The nested quadrats show the cover abundance of native plants increasing to 25 % for most species.
Native species increasing in abundance include: Leptospermum laevigatum, Banksia integrifolia, Lomandra longifolia, Cupaniopsis anacardioides, Carpobrotus glaucescens, Senecio lautus, Einadia hastata, Pelargonium australe, Solanum aviculare, and Commelina cyanea. All mature bitou plants have been killed in the area targeted. The large seed bank in the dunes will mean continued emergence of seedlings requiring further maintenance work for several years to come. The high resilience of the site has meant that no planting has been necessary. Mature Banksia integrifolia and Cupaniopsis anacardioides specimens are recovering following bitou bush removal from around their bases. These trees will improve the canopy on site resulting in a decrease in bitou bush regrowth and germination.
Summary
The resilience on site is higher than first anticipated, with over 30 native species being recorded in the area where bitou has been removed. The site will require ongoing maintenance, the timeframe for this will reduce as native canopy and ground cover is established. An integrated pest management approach has been successful on site using cut and paint, hand pulling , splatter gun and spray unit spraying weed control methods. Work will continue on site with community volunteers, university students and NPWS staff.
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Bitou bush regrowth infesting dunes at Wamberal
Lagoon | | After bitou bush control at Wamberal Lagoon |
Long Reef Headland, Collaroy Site information
Long Reef is located between Dee Why and Collaroy Beaches on Sydney's Northern Beaches. Long Reef Headland is a popular spot for walkers, as it provides spectacular views to the north as far as the Central Coast and the south, to Manly. The site has high ecological significance as it comprises important remnants of coastal bushland and native grasslands, and supports several significant ecological communities. Long Reef is a Wildlife Protection Area and Aquatic Reserve, which is home to several threatened plants and ecological communities and provides habitat for threatened animals and marine invertebrates.
The bitou bush problem
Bitou bush invasion is the major threat to biodiversity at Long Reef Headland, and Reefcare volunteers have been working on controlling it since 1997. In the 1950s and 60s, bitou bush was introduced to many NSW coastlines in an attempt to stabilise sand dune erosion. Bitou bush probably reached Long Reef Headland as a result of this practice.
Native species threatened by bitou bush invasion
There are 119 native plant species, five native frogs, nine native reptiles, 136 native birds and three native mammals recorded at Long Reef Headland, including several threatened species. The priority biodiversity at risk from bitou bush invasion includes Westringia fruticosa, Viola betonicifolia and the endangered ecological community, Themeda Grassland on Seacliffs and Coastal Headlands.
Collaborative action
The site is managed by Warringah Council as a Wildlife Protection Area. Warringah Council's Bushland Management Team along with Reefcare volunteers, with support from the Sydney Metropolitan Catchment Management Authority (SMCMA) and the Office of Environment and Heritage (OEH), have been working on controlling bitou bush infestations along the headland.
Control and restoration activities
The Reefcare volunteer group has been working at the site for the past 12 years, targeting bitou bush and lantana, and have progressively regenerated a large area of Themeda Grassland. Warringah Council has initiated a large scale, long term bitou bush control and bush regeneration project as part of their bushland management program, with support from OEH and the SMCMA through grant funding. Control and restoration activities include extensive hand weeding, on-ground and aerial spraying, strategically targeting more resilient areas and linking core areas within the site. A staged method of control has been favoured, by firstly removing bitou bush from the immediate vicinity of the priority species and Themeda Grassland community, then expanding the control area to create a greater buffer zone, with continual follow-up control. The emphasis has been on natural regeneration where there is evidence of native germination, but replacing removed bitou bush with a diverse range of native endemic plants on eroding sections of the slope.
Interim results
In the past, the remnant Themeda Grassland has not responded well to bitou bush removal on site. This could have been caused by a variety of factors such as climate, site disturbance, removal of the bitou bush buffer, or lack of maintenance. The need to be more strategic in the way resources are utilised was recognised by land managers, and more emphasis has been placed on detailed planning at the site to achieve restoration. More recently, several remnant patches of Themeda australis were uncovered on the cliff line on the southern edge of the headland. Site resilience has been good, as it is a relatively unmodified soil profile on the cliff line.
Summary
The endangered ecological community and species present at Long Reef Headland are responding well to the bitou bush control program, but staged removal with a focus on protecting biodiversity set out in the Bitou Bush TAP has been fundamental. The site will require ongoing maintenance, with bitou bush seedlings continuing to pop up, but also to control secondary weed invasion that has occurred.
Bass Point Reserve, Shellharbour
Site information
Bass Point Reserve occupies an area of approximately 71ha on an undeveloped portion of coastline extending east from Shellharbour township on the South Coast of NSW. This prominent coastal headland is managed for passive recreation and nature conservation and is surrounded by a quarry, urban development and narrow foreshores to the north and south. The Reserve is home to at least ten vegetation communities including one endangered ecological community and three threatened plant species. The Reserve is of particular significance to the local Aboriginal community, containing several culturally significant sites.
The bitou bush problem
In 1948, bitou bush was deliberately planted on the sand dunes of nearby Perkins Beach, Port Kembla, to stabilise the dunes from erosion following sandmining of the area. It is suspected that bitou bush spread from these early plantings, aided by birds and foxes, and infested Bass Point a short time later. Over the next fifty years bitou bush grew literally unchecked throughout the Reserve where it progressively invaded all vegetation communities and began threatening the very existence of the park itself. Surveys and aerial inspections in 1998 revealed that the majority of the park was heavily infested and bitou bush was a serious threat to the conservation value and ecological diversity of the Reserve.
Native species threatened by bitou bush invasion
Bass Point Reserve houses some of the last remaining intact coastal vegetation communities in between the Royal National Park near Sydney and Seven Mile Beach National Park to the south, near Gerroa. The Reserve also has the last remaining significant stand of Littoral Rainforest in the Illawarra catchment and contains at least three nationally threatened plant species: Cynanchum elegans, Zieria granulata and Pimelea spicata.
Site assessments undertaken in 2000 as part of the development of a weed management strategy for Bass Point, revealed that bitou bush was having a detrimental impact on the high priority species and ecological community, however with appropriate control, effective rehabilitation could be achieved.
Collaborative action
The Reserve is managed by Shellharbour City Council (SCC). Bitou bush control at Bass Point has been undertaken since 1999 as a collaborative partnership between SCC, the Illawarra District Noxious Weeds Authority, the Illawarra Aboriginal Lands Council and the Southern Rivers Catchment Management Authority. In addition, local residents have assisted programs since 2004 and the Department of Corrective Services has been integral in providing labour to undertake bitou control throughout some of the heaviest infested areas of the reserve. The Office of Environment and Heritage has been instrumental in coordinating bitou control within the most sensitive areas of the park, following the listing of Bass Point as a high priority Bitou TAP site in 2007.
Good co-operation also exists with adjoining (private) landholders, particularly the Killalea State Park Trust (another TAP site) that abuts the park to the south.
Control and restoration activities
Bitou control has been undertaken at Bass Point since at least 1999, but the implementation of the TAP, beginning in 2007, focused this control effort on protecting high priority biodiversity. Control programs have primarily involved aerial spraying of all heavy and inaccessible infestations,complimented by the hand removal and/or spot spraying in more accessible and sensitive locations. Since commencement of the TAP in 2007, control has primarily involved the hand removal and/or the cut-and-paint technique of bitou bush threatening Littoral Rainforest, both within canopy gaps and in the surrounding ecotone area. Hand removal of bitou bush and other weeds was also undertaken in areas adjacent to individual specimens of Zieria granulata and Cynanchum elegans.
Annual monitoring using photo points is used to determine the success of bitou control and recovery of native species.
Interim results
Bitou bush was target weeded along the entire length (670m) of the Littoral Rainforest ecotone (average width of 30m) and in approximately 1000m2 of canopy gaps. Comprehensive weeding was also carried out around populations of Zieria granulata and Cynanchum elegans, with approximately 900m2 of bitou bush and other weeds removed around each plant/population identified.
Control works have resulted in a >90% decline in the presence of bitou bush across all treated areas with a noticeable increase in the number of individuals or seedlings of Cynanchum elegans and Zieria granulata. At least 27 Zieria granulata seedlings were recorded within 5m of mature trees following protection works. One new, previously unrecorded population of Cynanchum elegans was found during the implementation of the TAP. Ongoing weed control is continuing within these areas, with emphasis also being afforded to secondary weeds such as Lantana, Panic Grass, Cape Ivy and Turkey Rhubarb.
Summary
Funding received under the Bitou TAP has done much to mitigate and ameliorate the impact of bitou bush on the threatened species and endangered ecological community that are most at risk. It has also complimented existing programs within the park that began in 1999. Preliminary control works signal positive results.
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Hand weeding of bitou bush at Bass Point | | Nationally endangered Cynanchum elegans at risk
from bitou bush at Bass Point |
Warrain/Currarong Beach
Site information
The Warrain and Currarong Beach site is located on the South Coast of NSW, stretching along 9km of coastline from the townships of Culburra Beach in the north, to Currarong at the southern end of the site. Warrain Beach provides a land barrier between the waters of the nationally significant Lake Wollumboola and the Tasman Sea. The ecological significance of the site is evident from the suite of endangered ecological communities (EECs) that form the diverse mosaic of vegetation. These relatively isolated beaches are popular for beach fishing and surfing.
The bitou bush problem
Stabilisation works following sand mining operations at Culburra Beach in the 1960s is the likely source of the bitou bush infestation at the site. Infestation levels are higher in the northern sector of the site and reduce significantly towards the southern extremity. Private land to the west of Warrain Beach poses another source of bitou bush infestation, where control is currently not as vigorous and consistent.
Native species threatened by bitou bush invasion
Eight ecological communities are present on site, including, Coastal Banksia Woodland, Coastal Scrub (Leptospermum laevigatum/Acacia longifolia subsp. sophorae), Frontal Dune Vegetation Complex, Coastal Wetlands (SEPP 14); and four EECs: Sydney Freshwater Wetlands, Bangalay Sand Forest, Swamp Oak Floodplain, and Littoral Rainforest. The listed high priority species of Westringia fruticosa, Stackhousia spathulata and Wilsonia backhousei are now located away from the impacting bitou bush infestations, but the Chamaesyce psammogeton specimens are located within the highly infested areas of the site.
Collaborative action
Shoalhaven City Council and the Department of Environment, Climate Change and Water are the key land managers, and an integrated control effort is implemented between these agencies throughout the site. Community volunteers from Culburra Beach also participate in on-ground works where practicable.
Recently, a neighbouring private landholder has participated in a collaborative aerial spraying exercise with the other land managers. This cooperation is a very positive step towards comprehensive bitou bush control and biodiversity protection at the site.
Control and restoration activities
Prior to the TAP, initial control was in the form of aerial spraying in the late 1990s, but lack of concerted follow-up work resulted in minimal reduction of bitou bush. Further aerial spraying efforts in 2003 and 2005 helped to contain infestations, but the establishment of the Threat Abatement Plan (TAP), a site-specific management plan and TAP funding enabled control works to become integrated, intensive and focussed on protecting priority biodiversity. Infestation levels now only demand application of hand control methods. Secondary weed infestations of lantana (Lantana camara), dune onion weed (Trachyandra divaricata) and sea spurge (Euphorbia paralias) have also been addressed.
Four-wheel drive vehicles previously accessing the site have been restricted, limiting the damage to the lower foredune and listed high priority species and EECs.
A monitoring program consisting of five photopoints, quadrats to monitor threatened species populations, and bitou density mapping is implemented prior to and following control applications.
Interim results
In 2007 only one specimen of the threatened high priority species Chamaesyce psammogeton was found at the site. In 2009, seven specimens have been identified since intensive bitou bush control has been implemented. Monitoring results have revealed that bitou bush is being contained and eliminated from listed EECs, further evidence that control efforts are effective.
Summary
The TAP has shifted weed management focus from generalised bitou bush control to preservation and restoration of priority plant species and EECs. This change of focus has heightened land managers awareness of the status of high risk plant species and ecological communities. The project has also made possible an increase in integrated weed control efforts, thus improving the environmental health of this ecologically significant site.
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Endangered Chamaesyce psammogeton at risk
from bitou bush at Warrain and Culburra Beaches | | Monitoring plot to measure the recovery of
Stackhousia spathulata |
