Boorowa
Indicator: Pest Plants
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What the results tell us for Boorowa
Boorowa Council has identified nine weeds of priority. The total area of infestations for seven species decreased since 2004, while known infestations of Chilean Needle Grass were contained, and known outbreaks of fireweed along roads were eradicated. All the priority species have the potential to adversely impact on primary productivity as they are pasture invasive, with two potentially harmful or poisonous to livestock.
Council carried out weed control activities for all nine priority weeds during the reporting period, and achieved reductions in densities for most of the species. 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 or weed management in state forests associated with Boorowa Council area.
Pest plant infestations
Nine plant species were identified as priority pests in the Boorowa Council area during the reporting period: African Lovegrass (Eragrostis curvula), Silverleaf Nightshade (Solanum eldeagnifolium) Blackberry (Rubus fruticosus), Scotch Thistle (Onopordum acanthium), Chilean Needle Grass (Nasella neessiana), Serrated Tussock (Nassella trichotoma), St John's Wort (Hypercum perforatum), Fireweed (Senecio madagascariensis) and Serrated Tussock (Nassella trichotoma). All these species have the potential to adversely impact on primary productivity as they are pasture invasive. St John's Wort and Serrated Tussock are also potentially harmful or poisonous to livestock.
The priority pest plant species are invasive and have the potential to reduce primary productivity, with St John's Wort also poisonous to stock, and Blackberry potentially able to restrict stock access to water courses. A number of the priority weed species also have the potential to negatively impact on two threatened ecological communities that occur in the Council area. The communities are 'Natural Temperate Grasslands of the Southern Tablelands of NSW and the ACT' which is listed as nationally Endangered under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999, and 'White Box Yellow Box Blakely's Red Gum Woodland communities' which is listed as Critically Endangered under the Commonwealth's EPBA Act 1999 and Endangered under the NSW Threatened Species Conservation Act 1995. No information is available to assess the potential impact of these weeds on these threatened plant communities.
The location, approximate area and density of infestation of the seven major pest plants in Bombala Council area are summarised in Table 1. In the previous reporting period, high and medium density infestations of Serrated Tussock and St John's Wort were reported to be decreasing and low and scattered plants were either increasing or stable. This trend continued in the current reporting period for these species. In the previous reporting period, high density infestations of African Lovegrass were reported to be increasing, medium density infestations were decreasing and low density and scattered plants were stable.
Table 1 Priority pest plants in Boorowa Council area, July 2000 to June 2008 (opens in new window)
In the current reporting period, areas of infestations of all species decreased. Refer to Table 2 to see the total change in relative abundance and spread (as a % ) resulting from implementation of controls and management plans for these priority weeds. (Note that total change in relative abundance and spread (as a % ) resulting from implementation of controls and management plans for weed categories is between 2001 and 2008, ie. between two reporting periods).
The largest weed infestations were Blackberry (Rubus fruticosus) and Scotch Thistle (Onopordum acanthium). Council control measures have had success in controlling these weeds. No information was available to assess the status of weeds, including priority weeds, within conservation areas. No information was available regarding the presence of pest plants within state forests located wholly or partially within the Council area.
Pest plants as threatening processes
A number of the priority weed species have the potential to negatively impact on biodiversity and native vegetation. Boorowa Council has occurrences of four threatened ecological communities listed nationally or in NSW, or both, (DECC, 2008b; DEWHA, 2008a) (Note: threatened ecological community lists are generated based on Bioregions). All of these communities are at risk from inappropriate fire regimes (DECC, 2008b, DEWHA, 2008b). No information was available to assess the impact of fire on these communities during the current reporting period.
All of these threatened ecological communities are considered at risk from invasive weeds (DECC, 2008d, 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.
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 (DEC 2008c):
- competition with or displacement of native species
- local and regional declines in many native plant species and communities.
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 with Council boundary.
Pest plant control activities by Boorowa Council
Pest plants are controlled as required by Regional Weed Management Plans. These Plans cover the Southern Tablelands and South Coast Noxious Plants Committee area. The Boorowa Council applies for funds to address the aims and objectives of relevant Plans from NSW Agriculture grants and from any other government funds available. Local weed management programs are in place to target local infestations.
Regional Weed Management plans for the Southern Tablelands- Boorowa Council remained active during the reporting period covering seven pest plant species (see Table 2). The major objective of all priority weed control programs within the Council area is to ensure maximum suppression and destruction of declared noxious weeds on private property and public lands.
Table 2. Pest plant control in Boorowa Council area, July 2004 to June 2008 (opens in new window)
Control actions for the major weeds within Boorowa Council area focused largely on preventing or minimising spread into 'clean' or uninfested areas, minimising spread and propagule dispersal, controlling isolated infestations, faciliitating coordination between land managers and coordinating on-ground control efforts by landholders, and community education and extension and awareness raising exercises. Weed control methods predominantly involved the use of herbicide, with some mechanical and manual removal. Biological control methods were also used in conjunction with other methods to control Patterson's Curse (crown weevils) and Bridal Creeper (leafhoppers and rust fungus).
Expenditure on and effectiveness of pest plant control
Expenditure on weed control and outcomes of control programs for priority pest plant species within the Council area are summarised in Table 2. The majority of funding for control of nine of priority weed species was sourced either through Council and/or NSW Agriculture funding, with an Nation Heritage Trust Grant for the control of Blackberry in 2005-2006.No figures were available for expenditure during the current reporting period on weed control by community groups or individuals.
During the current reporting period, no information was available to assess the effectiveness resulting from implementation of controls and management plans for priority weeds. Refer to Table 2 to see the total change in relative abundance and spread (as a %) resulting from implementation of controls and management plans for priority weeds between 2001 and 2008, ie. between two reporting periods.
Continued problems with the timely granting of NSW state government annual funding affects weed management programs. Programs are generally effective and this has increased with closer cooperation between community and Council and other land management agencies. Joint programs between Council, other land management agencies and private landholders have resulted in much more effective outcomes.
For information on the breakdown of the percentage of total area treated for each of the nine priority weeds by local Government, community groups and individuals, refer to Table 2.
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, 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
