Bega Valley
Indicator: Pest Plants
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What the results tell us for Bega Valley
Bega Valley Shire Council has identified nine weeds of priority within the Shire. Many of the weed species have the potential to adversely impact on primary productivity, while three species are also poisonous to livestock. Many of the weed species also have the potential to adversely impact on biodiversity and native vegetation communities.
The Shire Council carried out weed control activities for all nine priority weeds during the reporting period, and achieved reductions in densities for seven species. Overall densities of seven weed species were reduced during the current reporting period. No data were available on the status of weeds within various national parks and other reserves over the reporting period, or on weed management activities undertaken by the New South Wales (NSW) Department of Environment and Climate Change (DECC) in those areas. No data were available on weeds or weed management in the 23 state forests located wholly or partly within the Shire.
Pest plant infestations
Nine plant species continue to be identified as priority weeds in Bega Valley Shire since the previous reporting period: African Lovegrass (Eragrostis curvula), Bitou Bush (Chrysanthemoides monilifera), Blackberry (Rubus fruticosus), Cape Broom (Genista monspessulana), Crofton Weed (Ageratina adenophora), Fireweed (Senecio madagascariensis), Paterson's Curse (Echium spp.), St John's Wort (Hypericum perforatum) and Serrated Tussock (Nassella trichotoma).
Many of the species have the potential to adversely impact on the conservation values of native vegetation communities and on primary productivity. St John's Wort, Paterson's Curse and Fireweed are also poisonous to livestock. Many of the weed species also have the potential to adversely impact on biodiversity and native vegetation communities.
The location, approximate area and density of infestation of the nine priority pest plant species are summarised in Table 1.
The area of infestation of four of the priority weeds decreased since 2004:
- Bitou Bush, by five hectares
- Blackberry, by approximately 700 hectares
- Paterson’s curse, by approximately 200 hectares
- Serrated Tussock, by approximately 340 hectares.
Table 1. Priority pest plant species in Bega Valley Shire, July 2004 to June 2008 (opens a new window)
The 2000 and 2004 State of the Environment Reports highlighted that the area of infestation of Fireweed was increasing rapidly throughout the Shire. The latest results indicate this increase has continued during the current reporting period, during which Fireweed infestations increased by 45% (compared with a 25% increase in the 2000 to 2004 reporting period). Although the increase is significant, most (75%) infestations were at a 'Rare and isolated' density. Other weeds that appeared to have increased their area of infestation in the Shire included African Lovegrass; its area of infestation increased approximately 11% over that in 2004, although the infestations during the current reporting period were also at a 'Rare and isolated' density.
Figures for weeds, particularly Paterson's curse and St John's Wort, fluctuate depending on the growing season and do not present an accurate long term picture of the level of infestation. Annual funding from Council and NSW Department of Primary Industries dictates what is spent on management of a specific weed. Funding for specific weed management projects or weed management within wider vegetation management projects from Southern Rivers Catchment Mangement Authority (CMA) has assisted in specific weed control programs. These have included Chilean needle grass, coastal environmental weeds and riparian weeds projects. The amount spent may not give a true picture of success in reducing areas and/or densities of the weed. Mapping is done as inspections are carried out and does not cover the entire Shire. More generalised maps can be produced to reflect areas of Core, Marginal and Rare and Isolated infestations as well as areas where the weed is absent. Mapping descriptions are used in reporting and to develop targeted management strategies to maximise outcomes.
Pest plants as threatening processes
A number of the priority weed species also have the potential to negatively impact on biodiversity and native vegetation. According to The Department of Environment and Climate Change threatened species website, there are 16 priority actions under the ‘habitat management: weed control’ recovery strategy in the Bega Valley Shire. These actions apply to 15 threatened species, populations and communities, including six Endangered Ecological Communities.
A priority action to conserve threatened ecological communities includes the undertaking of weed control for Bitou Bush and Boneseed at priority sites in accordance with the approved Threat Abatement Plan and associated PAS actions. This priority action applies to the following threatened ecological communities. Freshwater wetlands on coastal floodplains of the NSW North Coast, Sydney Basin and South East Corner bioregions, Littoral Rainforest in the NSW North Coast, Sydney Basin and South East Corner Bioregions and Swamp oak floodplain forest of the NSW North Coast, Sydney Basin and South East Corner bioregions. To view other priority actions for threatened species, populations and communities relating to weeds, refer to (DECC, 2008e).
Bega Shire may contain 13 threatened communities listed as endangered or critically endangered within NSW or nationally (DECC, 2008b; DEWHA, 2008a). (Note: threatened ecological community lists are generated based on Bioregions). Twelve threatened communities are listed under the NSW Threatened Species Conservation Act 1995, one is listed under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999 (see Ecological communities).
All of the 13 threatened ecological communities are considered at risk from invasive weeds (DECC, 2008d, DEWHA, 2008a). These include pasture weeds, noxious weeds and environmental weeds. Weeds compete with native plants for resources such as light and nutrients, and can aggressively invade areas, displacing native plants and animals. The impacts of a number of weed species such as Bitou Bush (Chrysanthemoides monilifera) and exotic perennial grasses are identified as Key Threatening Processes. The control of weeds at these priority sites can help recover threatened species. No information is available to assess the impact of weeds on these threatened plant communities.
A final determination to list 'Invasion of native plant communities by exotic perennial grasses' as a key threatening process under the Threatened Species Conservation Act 1995 (NSW) was made by the NSW Scientific Committee during the current reporting period. The grass species included African Lovegrass and Serrated Tussock, both of which are of concern within the Shire. The impacts of exotic perennial grasses as outlined in the final determination include (DECC 2008c):
- competition with and/or displacement of native species
- local and regional declines in many native plant species and communities.
Invasion of native plant communities by Bitou Bush and Boneseed' was listed as a threatening process under the Threatened Species Conservation Act 1995 in the previous reporting period. The impacts of Bitou Bush as outlined in the final determination made by the Scientific Committee include (DECC 2008b):
- local and regional declines in many native plant species and communities
- alteration of structure and habitat for native vertebrate and invertebrate species, favouring proliferation of non-indigenous species.
A draft threat abatement plan was during the previous reporting period for Bitou Bush. This plan provides a collaborative strategy for Bitou Bush control and monitoring programs for the primary purpose of conserving threatened species in NSW (DECC 2008a).
Pest plant control activities by NSW Government agencies
No information was available regarding control programs undertaken by NSW Government agencies. No information was available regarding control programs for pest plant species within state forests that intersect the Shire.
Pest plant control activities by Bega Valley Shire Council
Pest plants are controlled as required by Regional Weed Management Plans and Catchment Action Plans. The former covers the Southern Tablelands and South Coast Noxious Plants Committee area and are currently being superseded by Catchment Action Plans. The coastal group of Councils applies for funds to address the aims and objectives of relevant Plans and individual Council plans. Local weed management programs are in place to target local infestations. Bega Valley Shire Council works closely with community groups to implement the aims and objectives of the Bega Valley Shire Council Weed Strategy, developed jointly with community groups and representatives of other government land management agencies in 2002. This Strategy is now incorporated in the Southern Rivers Catchment Management Association (SRCMA) Bega Sub-region Weeds Strategy.
The South Coast Regional Bitou Bush Strategy, which was developed during the previous reporting period, is applicable within the Australian Capital Region to the coastal areas of Bega Valley (see Broese and Wolfenden, 2001). Nine SRCMA CAP Bega Sub-regional weed strategies for the South Coast Region are active during the reporting period, which incorporate control programs under the CMA strategy (STSCNPC, 2008).
Table 2. Pest plant control in Bega Valley Shire, July 2004 to June 2008 (opens a new window)
NSW DPI funding support for weed management in the Shire is inadequate, not guaranteed for long-term projects and often not available until well into the financial year, making planning difficult. Reporting remains cumbersome, with reports required for all programs, rather than a single comprehensive report for weed management as a whole. Close cooperation with other land managers and community representatives on the Local Management Team of the Southern Rivers CMA has improved weed management capabilities through joint project and funding for specific programs.
Development of the SRCMA Catchment Action Plan and the Weed Strategy Bega Subregion, incorporating 2002 Bega Valley Shire Weeds Strategy, ensures a better coordinated weed management program. While some figures identify that a number of weeds have increased their range, weed control programs on Shire Council-owned and managed land and the private property inspection programs are increasingly effective. Education and awareness programs, field days and publicity are key components of successful weed management over all land tenures.
The majority of funding for weed control within the Shire was expended on African Lovegrass and Blackberry. The Shire Council carried out weed control activities for all nine priority weeds during the reporting period, and achieved reductions in densities for seven species (see Table 2). This resulted in African Lovegrass being reduced by 5% in high and medium density infestations, however 'Rare and isolated' infestations increased by 20%. Blackberry was reduced by 10%, 5% and 15% in high, medium and low density infestations respectively. The pest plant that had the greatest reduction in area due to control works was St John’s Wort, reducing 30% and 50% in medium and low density infestations respectively. Bitou Bush was reduced by 15% in low density infestations. Fireweed increased by 8%, 10% and 15% for high, medium to low density infestations respectively, while the change in relative abundance of Patterson’s Curse was not known.
A breakdown of the percentage of total area treated for each of the nine priority weeds by local Government, community groups and individuals is shown in Figure 1. Control measures for Cape Broom and Crofton Weed were undertaken wholly by the Shire Council whereas control measures for Fireweed and Serrated Tussock were undertaken largely by individuals, with small areas treated by the Shire Council and community groups. Community groups undertook 60% of control work on Bitou Bush with the remaining 40% being undertaken by the Shire Council. The percentages of weed infestation area treated by local Government, individuals and community groups would appear to reflect the tenure of the land on which the infestations occur. For example, Serrated Tussock and Fireweed predominantly occur on grazing land and as such the majority of their control was undertaken by individuals such as farmers.
About the data
A spread sheet was supplied to each Council, with fields summarising priority plant species, the status of control plans and their objectives. The spreadsheet also included a field nominating the types of control methods used and the areas that were treated, either by community groups, individuals or local government. A field describing the change in relative abundance within the density classes of high (75-100% cover), medium (20-74% cover) and low (1-19%) was also included. In compiling the Pest Plant indicator chapters, the authors compared this data to data for the previous reporting period (2000-2004), as well as sourcing information available on the DECC website. In some cases, missing data impeded comparison.
References
Broese, EA and Wolfenden, JAJ (2001) South Coast Regional Bitou Bush Strategy, Arnhem Environmental Impact Assessors, Armidale, viewed 29 September 2008, http://www.esc.nsw.gov.au/Weeds/BitouRegionalStrategy.pdf.
DECC—see Department of Environment and Climate Change
Department of Environment and Climate Change (2008a) Draft NSW Threat Abatement Plan—Invasion of native plant communities by bitou bush/boneseed (Chrysanthemoides monilifera), Department of Environment and Conservation, Hurstville, viewed 29 September 2008, http://www.nationalparks.nsw.gov.au/PDFs/TAP_draft_BitouBush_Boneseed.pdf
Department of Environment and Climate Change (NSW) (2008b) NSW Scientific Committee—Final Determination, Invasion of Native Plant Communities by Bitou Bush and Boneseed—Key Threatening Process Declaration, NSW Department of Environment and Conservation, viewed 29 September 2008, ‘http://www.nationalparks.nsw.gov.au/npws.nsf/Content/Invasion+of+native+plant+
communities+by+bitou+bush+and+boneseed+key+threatening+process+declaration
Department of Environment and Climate Change (NSW) (2008c) NSW Scientific Committee—Final Determination, Invasion of Native Plant Communities by Exotic Perennial Grasses—Key Threatening Process Declaration, NSW Department of Environment and Conservation, 29 September 2008, http://www.nationalparks.nsw.gov.au/npws.nsf/Content/Invasion+of+native+plant+
communities+by+exotic+perennial+grasses+key+threatening+process+declaration
Department of Environment and Climate Change (2008d), Threatened Species – species, populations and ecological communities in NSW , search on endangered ecological community, viewed 29 September 2008, http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/home_species.aspx
Department of Environment and Climate Change (2008e), Threatened Species – species, populations and ecological communities in NSW , Recovery and threat abatement, Bega Shire Council, viewed 13 October 2008, http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/pas_lga_recovery_details.aspx?
lga=Bega%20Valley%20Shire%20Councilandtype=habitat+management:+weed+control
Department of Environment, Water, Heritage and the Arts (Commonwealth) (2008a), Biodiversity, search on endangered ecological community, viewed 29 September 2008, http://www.environment.gov.au/biodiversity/index.html
Southern Tablelands and South Coast Noxious Plants Committee (2001a) Regional Weed Management Plan for Aquatic Noxious Weeds 2001–2006, Southern Tablelands and South Coast Noxious Plants Committee, viewed 29 September 2008,
STSCNPC—see Southern Tablelands and South Coast Noxious Plants Committee
