KEY THREATS AND SUGGESTED CONSERVATION ACTIONS There are many benefits to the long-term protection of Australia’s native biodiversity. Patches of native vegetation, such as the Grey Box Grassy Woodlands ecological community, provide a range of ecosystem services including management of water tables and flows, soil nutrient cycling, erosion and salinity reduction, carbon storage, and habitat for important functional species such as pollinators or predators of insect pests. They also provide wind breaks, shelter and food for stock, and exhibit some resilience to drought. Most of the remaining areas of this ecological community occur on private land. At present, less than 1% of what remains of the listed community in NSW is in formal conservation reserves. Slightly more of the community occurs in formal reserves in Victoria, with around 8% of the remaining area protected. The level of protection in South Australia is unknown but is likely to be similarly low. This section identifies the key threats to the Grey Box Grassy Woodlands ecological community, and possible actions that land managers may take to conserve the listed community on their land (Table 2). This list is not exhaustive, but highlights conservation actions that are a high priority at this time. Vegetation clearance and fragmentation Clearing and fragmentation of vegetation continue to pose serious threats to the Grey Box Grassy Woodlands ecological community. Much of the listed community coincides with what is now the wheat-sheep belt of eastern Australia and the community has been extensively cleared since European settlement as a result of its open, grassy structure and its association with relatively fertile soils. Cultivation for cropping destroys the propagule bank, which can include seeds, rhizomes and tubers of native species. Sites that have never been cultivated may retain a propagule bank for many years, allowing previously-dormant species to recover when conditions allow. Fragmentation due to continued vegetation clearance results in areas of native vegetation becoming isolated with connectivity between them being lost. Many of the remaining areas of the ecological community are small and highly fragmented. Smaller, more isolated areas become less able to support viable populations of native species or to maintain the ecosystem processes and services that sustain the ecological community. Small patches also have a lot of ‘edge’ area and little ‘core’ area. Some species, including many declining woodland birds,
Ehrharta calycina (perennial veldt grass) Holcus lanatus (Yorkshire fog) Marrubium vulgare√ (horehound) Nassella trichotoma †√ (serrated tussock-grass) Heliotropium europaeum√ (common heliotrope) Lycium ferocissimum †√ (boxthorn) Nassella neesiana †√ (Chilean Olea europaea*√ (European olive) * Widespread weed in this community †Weeds of National Significance (WoNS) in this community √A declared Noxious Weed in some jurisdictions.
Table 4: Impacts of exotic species and key management actions Impacts of exotic species Key management actions Direct loss of native species and decline in biodiversity. Weeds competing with native plants for space, water and nutrients. If left unmanaged, weeds will degrade and potentially dominate a site. Weeds can perpetuate a change in the nutrient cycle, in favour of exotic species over native species. Introduced predators, such as foxes and feral cats, competing with native predators and killing native animals. Introduced herbivores, such as rabbits, grazing, browsing and killing native plants. They can also disturb soil structure through extensive diggings or trampling. Identify the key weed and pest animals at a given site. Eradicate or manage and monitor weeds, pest animals and other problem species, including invasive native shrubs, following available best practice or management plans. Ensure use of chemicals or other mechanisms to control weeds and pest animals do not have any significant adverse impact on native species (for example, avoid broad-cast herbicide use such as aerial spraying). Minimise impacts to threatened species at known sites. Identify new and emerging weed and pest animal problems in the region. Act quickly to eradicate them before the problem becomes too impractical and expensive to fix. Prevent or minimise the addition of nutrients, such as fertilisers. Nutrient enrichment promotes weed invasion. In South Australia, the most serious woody weed is the European olive (Olea europaea), which has escaped from cultivation. Given the increase in throughout eastern Australia, olives may become a more serious threat in other areas in future. Land managers should also be aware of, and comply with, any local or state laws that require them to manage noxious weeds or pest animals on their property. Many weed species produce a lot of seed that is easily dispersed, e.g. seeds that are blown by wind, seeds produced in fleshy fruits that are eaten by animals and dispersed in droppings, or seed that “hitches a lift” on vehicles or is introduced to a property in purchased fodder or seed. One important control principle is to reduce the amount of seed that weeds produce, by spraying, burning or even grazing grassy weeds before seed is set. Another vital control measure is to avoid spreading weed seeds by regularly cleaning vehicles and farm machinery, especially before moving it to a new area. Careful sourcing of clean seed and fodder growing
Lindenmayer, DB, Cunningham, RB, Crane, M, Montague-Drake, R & Michael, D (2010). The importance of temperate woodland in travelling stock reserves for vertebrate biodiversity conservation. Ecological Management and Restoration, 11, p 27-30. Lunt, I., Barlow, T. & Ross, J. (1998). Plains wandering: exploring the grassy plains of south-eastern Australia. Victorian National Parks Association Inc. and Trust for Nature Victoria. McIntyre, S., McIvor, J. & Heard, K. (eds) (2002). Managing and conserving grassy woodlands. Melbourne: CSIRO Publishing. Natural Resources Advisory Council NSW (2010). Understanding Our Native Grasslands: agricultural, environmental and indigenous values and management for the future. These references were current at the time of publishing; please refer to the relevant agency’s website for any updated versions. Other useful websites Relevant Catchment Management Authorities/Natural Resource Management Boards NSW: Murray CMA - Murrumbidgee CMA - Lachlan CMA - Central West CMA – Namoi CMA - Victoria: North East - Goulburn Broken - North Central - Mallee - Wimmera - Glenelg-Hopkins CMA - Corangamite CMA - Port Philip and Westernport CMA - South Australia: Northern and Yorke NRM Board - Adelaide and Mount Lofty Ranges NRM Board - South East NRM Board - Caring for our Country Additional copies of this document For further information or additional copies of this publication please contact the department’s Community Information Unit: Telephone: 1800 803 772 Email: Mail: Community Information Unit Department of Sustainability, Environment, Water, Population and Communities GPO Box 787 Canberra 2601