Yass Valley
Indicator: Pest Plants
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Yass
Yass Valley Council has identified nine weeds of priority within the Council area. All the priority species have the potential to adversely impact on primary productivity, with four being potentially harmful or poisonous to livestock. A number of the priority weeds also have the potential to adversely impact on biodiversity and native vegetation.
During the current reporting period, Council carried out control activities for all priority weeds, however no information is available on the effectiveness of these control methods for the current reporting period (Table 1. outlines total change in relative abundance and spread (as a % ) resulting from implementation of controls and management plans between 2001 and 2008,over two reporting periods).
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 the Yass Valley Council area.
Pest plant infestations
Nine plant species were identified as priority pests in the Yass Valley during the reporting period: African Lovegrass (Eragrostis curvula), Silverleaf Nightshade (Solanum eldeagnifolium) Blackberry (Rubus fruticosus), Scotch Thistle (Onopordum acanthium), Chilean Needle Grass (Nasella neessiana), 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 may occur in the Council area. No information is available to assess the potential impact of these weeds on these threatened plant communities.
The largest infestations were Blackberry, Patterson’s Curse and Serrated Tussock. The location, approximate area and density of infestation of the seven major pest plants in Yass Valley Council Area are summarised in Table 1.
Table 1. Priority Pest Plants in Yass Valley Shire, July 2004 to June 2008 (opens in new window)
During the current reporting period, Council carried out control activities for all priority weeds, however no information is available on the effectiveness of these control methods for the current reporting period (Table 1. outlines total change in relative abundance and spread (as a % ) resulting from implementation of controls and management plans between 2001 and 2008,over two reporting periods).
Pest plants as threatening processes
Most of the priority weed species have the potential to negatively impact on biodiversity and native vegetation. The Yass Valley Council area may have occurrences of four threatened ecological communities listed nationally or in NSW (DECC, 2008a; DECC, 2008b; DEWHA, 2008a) (Note: threatened ecological community lists are generated based on Bioregions). Two threatened ecological communities are listed under the NSW Threatened Species Conservation Act 1995, two are listed under the 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 Council. The impacts of exotic perennial grasses as outlined in the Scientific Committee's final determination include (DEC 2008a):
- 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 the Council.
Pest plant control activities by Yass Valley Council
The control of pest plants within the Council is undertaken according to Regional and Local Weed Management plans. Regional Weed Management plans cover the area for which the Southern Tablelands and South Coast Noxious Plants Committee is responsible. Regional plans remain active and cover infestations of the seven priority weeds within the Council. Local Weed Management plans have been in place for over 30 years for all weed species, being were superseded by the Regional Weed Management plans. Two weed species are covered by Local Weed Management plans. Regional Weed Management plans for the Southern Tablelands and South Coast Region were developed during the reporting period for the pest plant species shown in Table 2.
Table 2. Pest plant control in Yass Valley Shire, July 2004 to June 2008 (opens in new window)
Control actions for the major weeds within Yass Valley Council focused largely on prioritising operational and control response, mapping, preventing spread into clean areas, controlling all rare and isolated infestations, strategically reducing infestations in marginal and core areas, implementing protocols to prevent seed spread, education and extension, facilitating coordination between land managers, continually monitoring major roadways such as Hume Highway for isolated outbreaks, protecting vulnerable high conservation areas, and the use of biological control methods for certain weed species.
Weed control methods used within the Council predominantly involved the use of herbicide. Other methods used included some slashing for African Lovegrass, manual removal and burning for Chilean Needlegrass and Gorse, and biological control methods were used in conjunction with other methods to control Blackberry and St John’s Wort.
Expenditure on and effectiveness of pest plant control
The majority of funding for control of nine of priority weed species was sourced either through Council and/or NSW DPI. A high proportion of funds were spent on controlling Serrated Tussock and St John's Wort, with substantial funding allocated to Serrated Tussock for 2007-2008. 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 government annual funding affects weed management programs. Programs are generally effective and this has increased with closer cooperation between community and Council 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
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
