Snowy River
Indicator: Pest Plants
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Please note: Text or data highlighted in this colour represent an update to this indicator for the period 2008/09.
What the results tell us for Snowy River
Snowy River Shire Council identified 12 weeds of priority within the Shire. All the priority weed species have the potential to reduce primary productivity, while three species are poisonous or potentially harmful to livestock, and one species also has the potential to restrict stock access to water courses. All the priority weed species also have the potential to adversely impact on biological diversity and native vegetation, including four threatened ecological communities in the Shire.
The Shire Council undertook treatment measures along roadsides and in its reserves for all priority pest plant species during the reporting period, and has achieved a high level of control in those areas. Some work has been undertaken on vacant Crown Lands with limited funds provided by the NSW Department of Lands, however further treatment is required to achieve control. No information was available on the status of weeds within various national parks and other reserves over the reporting period, or on weed management activities undertook by the New South Wales (NSW) Department of Environment and Climate Change (DECC) in those areas. No information was available on weeds and weed management in the two state forests located partly within Snowy River Shire.
Pest plant infestations
Twelve priority pest plant species were identified in the Snowy River Shire during the reporting period: African Lovegrass (Eragrostis curvula), Bathurst Burr (Xanthium spp), Blackberry (Rubus fruiticosus), Broom (Cytisus scoparius), Gorse (Ulex nutans), Horehound (Marrubium vulgare), Nodding Thistle (Carduus nutans), Scotch Thistle (Onopordum acanthium), Serrated Tussock (Nassella trichotoma), St John's Wort (Hypericum perforatum), Sweet Briar (Rosa rubiginosa) and Vipers Bugloss (Echium vulgare).
All the priority pest plant species have the potential to reduce primary productivity, with St John's Wort, Vipers Bugloss and Serrated Tussock also poisonous or potentially harmful to livestock, and Blackberry potentially able to restrict stock access to water courses. The 12 priority species also have the potential to adversely impact on four threatened ecological communities that occur in the Shire.
The location, approximate area and density of infestation of the 12 major pest plants in Snowy River Shire are summarised in Table 1.Three pest plant species decreased across all categories (low, medium and high density infestations) during the reporting period, while a further three pest plant species decreased across medium and high categories, with small increases in low density infestations. Four pest plant species was reported to show increases across all categories, while Horehound remained stable across all categories.
Table 1. Priority pest plant species in Snowy Rivers Shire, July 2004 to June 2008 (opens in new window)
Eight national parks and other conservation reserves are located wholly or partly within Snowy River Shire. Nineteen pest plant species were considered possible weeds in these areas during the previous reporting period (see 2004 SoE Report). No information was available to assess the status of weeds within conservation areas during the current reporting period.
No information was available regarding the presence of pest plants within the two state forests partly located within the Shire's boundary.
Pest plants as threatening processes
A number of the priority weed species also have the potential to negatively impact on four threatened ecological communities that occur in the Shire Council area. Snowy River Shire may contain five threatened ecological communities listed as endangered or critically endangered within NSW or nationally (see Ecological communities) (DECC, 2008a; DECC, 2008b; DEWHA, 2008a). (Note: threatened ecological community lists are generated based on Bioregions). Two are listed under the NSW Threatened Species Conservation Act 1995, three are listed under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999.
All of these threatened ecological communities are considered at risk from invasive weeds (DECC, 2008b, DEWHA, 2008a) particularly when existing as small and/or fragmented remnants. These include exotic perennial grasses, 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 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 was made by the NSW Scientific Committee during the previous reporting period. The grass species included Serrated Tussock, which is a species of concern within the Shire. The impacts of exotic perennial grasses as outlined in the Scientific Committee's final determination include (DECC 2008c):
- competition with or displacement of native species
- local and regional declines in many native plant species and communities.
According to DECC threatened species website, there are 3 priority actions under the "habitat management: weed control" recovery strategy in the Snowy River Shire Council. These actions apply to three threatened species, (Two plants and one rodent) (DECC, 2008c).
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 the presence of pest plants within the two state forests partly located within the Shire's boundary.
Pest plant control activities by Snowy River Shire Council
The Snowy River Shire Local Government Area forms a portion of the Monaro Sub-Region along with Cooma-Monaro and Bombala Councils. Pest plants are controlled within the Snowy River Shire as required by the Snowy River Shire Local Management Plans for each species. The Local Management Plans are amalgamated into a Sub-regional Strategy that specifies the overarching goals that underpin the Southern Rivers Catchment Action Plan for the region. The Monaro group of Shire Councils applies for funds to address the aims and objectives of relevant Plans from NSW Agriculture grants and from individual Shire Councils
Control programs for 12 priority weeds have been in place within the Shire since the 1950's. Since the last reporting period, a total of 21 Local Management Plans have been developed for the control of priority weeds (see Table 2). The current control program, which involves the use of contractors (rather than Shire Council staff) to undertake works, was initiated in 1997. The Shire Council weed control program covers 1,600 hectares of roadsides and 450 hectares of Shire Council managed reserves. Although control work is not undertaken over the entire extent of these areas, these areas are inspected for the presence of the priority weeds.
Table 2. Pest plant control in Snowy River Shire, July 200 to June 2009 (opens in new window)
Table 2 was updated to include data for 2008/09.
The current sub-regional plans outline management actions for the period from 2003 to 2009. The major objective of all priority weed control programs within the Shire is to ensure maximum suppression and destruction of declared noxious weeds on private property and public lands.
Control actions for the major weeds within Snowy Rivers Shire focused largely on ensuring that land managers meet obligations required by the Noxious Weeds Act 1993, ensuring local Plans are linked with Regional and State Plans, controlling existing infestations to reduce the spread from these areas to clean land, controlling new and isolated infestations, developing control methods (including biological control), working with community groups and education. Weed control methods for priority species within the Shire predominantly involved the use of herbicide, cultivation, slashing, grazing and physical removal. Biological control methods were also used in conjunction with other methods to control Paterson's Curse, Nodding Thistle and St John's Wort. Fire was used in conjunction with other methods to control African Lovegrass, including limited chipping.
Council is represented on the Local Management Team of the Snowy Monaro Biodiversity Conservation Strategy (SMBCS) Project, and various other projects to provide incentives to control perennial grassy weeds which threaten native grasslands in the region. Shire Council has also developed a number of new regional weed plans with their partners in the Monaro Regional Weeds Committee which will have a positive impact on native species in the Shire.
Council supports the SMBCS Project by monitoring weed infestations on properties in the pilot area through noxious weed inspections and providing advice and support to landholders involved in the pilot project.
Expenditure on and effectiveness of pest plant control
The majority of funding for weed control of ten of the priority species was sourced by Shire Council, with additional funds for the control of African Lovegrass and Serrated Tussock from the Department of Primary Industries. Although the figures were not available for the current reporting period, in many instances landholder expenditure within the Shire for control of most weeds, including Serrated Tussock, greatly exceeded expenditure by Shire Council and NSW State Government agencies. Apart from African Lovegrass, Serrated Tussock and St John's Wort, no information was available regarding control works undertaken by individuals (such as farmers) or community groups for any of the priority pest species.
Council undertook control measures for all priority pest plant species. Medium and low densities of Vipers Bugloss within the Shire were reported to decrease during the reporting period due to grazing pressure during the drought, while high density infestations remained unchanged. Blackberry decreased across all categories due to targeted control programs. Broom decreased across high and medium density infestations, however low density infestations have increased due to the high and medium infestation being reduced to low density.
High and medium density infestations of Sweet Briar decreased in abundance during the current reporting period, while low density infestations and scattered plants increased slightly due to the low priority of this species.
High, medium and low density infestations of African Lovegrass, Bathurst Burr and St John's Wort were reported to have decreased during the reporting period due to prolonged drought, bare ground and summer rainfall. Fire also aided increases of St John's Wort, through the spread of propagules from increased vehicle movement at the time of seed capsule production. The report for Serrated Tussock is similar, however low density areas and scattered plants remained unchanged despite bare ground due to drought.
High and medium density infestations of Scotch Thistle decreased due to biological control and heavy grazing pressure during the drought, while light infestations have increased in areas not stocked. The area of Gorse within the Shire was reduced by controlling one creek line. Areas of Nodding Thistle decreased in all densities within the current reporting period, largely because of regular control and biological control methods introduced effectively during the last reporting period. The changes in infestation areas of Bathurst Burr and Horehound within the current reporting period are not known.
Little data was available on a breakdown of the percentage of total area treated for each of the ten priority weeds by local Government, community groups and individuals, except for Shire Council and three weeds controlled by individuals (ie. 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
DECC—see Department of Environment and Climate Change
Department of Environment and Climate Change (NSW) (2008a) 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 (2008b), 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 (2008c), Threatened Species – species, populations and ecological communities in NSW , Recovery and threat abatement, Snowy River Shire Council, viewed 13 October 2008, http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/pas_lga_recovery_
details.aspx?lga=Bega%20SnowyRiver%20Shire%20Shire Council&type=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
DEWHA – see Department of Environment, Water, Heritage and the Arts
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
