Discussion Paper - Part A - Victorian Environmental Assessment ...

esult of being by-passed by irrigation channels. In otherareas, the lack of flooding for many years has weakenedor killed many river red gums (Brett Lane & AssociatesPty Ltd 2005). Other hydrological changes have resultedfrom the use of wetlands as areas to dispose of excessirrigation waters or salinity disposal.A mixed pattern of temporary and more permanentwetlands enables a diverse range of species to inhabitthe floodplains of the study area (Figure 5.19) (Parkinsonet al. 2002). Temporary wetlands are generally shallowwith high light levels and warm temperatures. This leadsto a high diversity and abundance of macroinvertebrateswhich provides a large food resource for wading birdssuch as egrets and spoonbills. Permanent water bodiesmay be of greater value to diving birds such ascormorants and azure kingfishers as the open waterfacilitates fish catching (Parkinson et al. 2002).Figure 5.19 Lake Murphy, near Kerang, floodeddue to an allocation of environmental water.For the four Ramsar sites in the study area, strategicmanagement plans have documented the level of risk tosite values from various activities and processes (DSE2003b, d, e, 2004h). They are summarised in Table 5.7.Although this summary does not assign a risk of grazingto wetlands in the Kerang wetlands, Gunbower forestand Barmah forest, grazing is detrimental to manyspecies, communities and ecological processes in thoseecosystems (Robinson & Mann 1998; Jansen &Robertson 2005).Pest Plants and Animals and PathogensPests and weeds are broadly defined as species that haveundesirable impacts, which may be economic,environmental or social. Pathogens are diseaseproducingorganisms, such as cinnamon fungusPhytophthora cinnamomi, that also have undesirableimpacts. Many of these species, but not all, areintroduced to Australia and their environmental impactsare particularly felt here because of the long prior periodof isolation of the Australian continent.Pest plants and animals are one of the greatest threatsto the integrity of biodiversity in the study area (DNRE2002g). They cause a wide range of impacts on theenvironment including damage to native vegetation,genetic pollution, displacement and loss of native wildlifeand alteration of ecological processes, such as waternutrientcycles and fire regimes. They affect primaryproduction through, for example, direct competition forresources and introduction and spread of diseases thataffect crops and livestock. They may affect amenitythrough preventing access to recreational areas and poserisks to human health (e.g. anaphylaxis as a result of beestings). The seriousness of the threat is underscored bynumerous pest and weed species and processes beinglisted, after rigorous scientific assessment, under theFlora and Fauna Guarantee Act 1988.The Victorian Pest Management—A Framework forAction (DNRE 2002a) provides the broad strategicdirection for pest management in Victoria. Subsidiarydocuments cover specific pests such as foxes, rabbits,wild dogs and weeds (DNRE 2002e, f, g).Significant investment in prevention and control isoccurring on public and private land. The Weeds andPests on Public Land Initiative is a major state governmentprogram to support pest plant and animal control innational parks, state forest and other public land inVictoria. The four-year, $14 million, initiative aims to:• Protect large areas of high value natural assets bypreventing and reducing the impact of weeds andpests;• Improve public land stewardship through a collaborativepartnership approach at the landscape level;• Minimise the movement of weeds and pests acrossthe public/private land interface; and• Engage the community in the management of publiclands;This program operates through on-ground projects inreducing pest plants and animals, increased strategicapproaches to pest management with a pilot study inthe Angahook-Otway region and through an increase inthe Good Neighbour program, which supports privatelandholders by controlling pests and weeds on theborder of public land. The complementary ‘TacklingWeeds on Private Land’ Initiative undertakes widerangingactivities on private land.Significant developments in pest and weed managementinclude taking a ‘biosecurity’ approach, with a focus onpreventing new problems. Large scale, cross-tenure,continuous programs, as demonstrated by the SouthernArk fox control project, also have great potential forimproved outcomes (DNRE 2002d; DSE 2003g). Acooperative approach to tackling pest animals, weedsand pathogens seems to be the most effective. To thisextent, government plays an important role inencouraging cooperation by all those with an interest indealing with pest animals, weeds and pathogens.Deliberate and ignorant introduction and spread ofspecies remains a problem. For example, aquariumspecies are released by often well-meaning people but atgreat risk to the environment. Policing of these activitiesbenefits from community surveillance and reporting.A weed is a plant that requires some form of action toreduce its harmful effects on the economy, environment,human health and amenity (Australian WeedsCommittee 2006). Weeds threaten the productivecapacity of land, water and biodiversity assets in Victoria.It is estimated that they cost Victoria $900 millionannually. Victoria faces new and increasing threats fromweeds (despite the success of current approaches) dueto the number of new species naturalising.76 River Red Gum Forests Investigation 2006