LC EPC Inquiry into Ecosystem Decline in Victoria Submission 449 Legislative Council Environment and Planning Committee Inquiry into Ecosystem Decline in Victoria Submission from Assoc Professor Barbara Wilson, Deakin University. The extent of decline of Victoria’s biodiversity has been of great concern to Victorians over many decades, particularly with regards to significant declines due to historic vegetation clearing, pest animals and weed invasion, river and marine declines. Weeds continue to have impacts over large areas of natural ecosystems e.g. Coast wattle and Pine invasions causing decline in ecosystem health in Brown Stringybark in western Victoria and impacts on food availability for endangered Black Cockatoos. Climate change impacts in Victorian ecosystems have only recently become more obvious and pervasive. In this submission I have taken the opportunity to focus on the extent of decline of Victoria’s biodiversity in the heathy woodland ecosystems of the eastern Otway ranges, and indicate opportunities to restore the environment. Decline in Heathy woodlands - Anglesea Heath, eastern Otway Ranges, Victoria The Anglesea Heath is recognised for its biodiversity, and a Land Management Cooperative Agreement was established to protect those values (Land Conservation Council Victoria 1985; McMahon and Brighton 2002). The Anglesea Heath (7141 ha) was leased for brown coal extraction over an area of 400 ha (1961–2015) and has recently been incorporated into the Great Otway National Park. The vegetation communities comprise a diverse mosaic of predominantly eucalypt forests, woodlands and heathlands, interspersed with dense wet shrublands. The rich mammal assemblage in the area consists of 15 small to medium-sized mammal species. The mammals include threatened species listed federally (EPBCA 1999) and in Victorian (FFGA 1988): the New Holland mouse (Pseudomys novaehollandiae) – Vulnerable (EPBCA), Threatened (FFGA); the Southern Brown Bandicoot (Isoodon obesulus obesulus)- Endangered (EPBCA), Threatened (FFGA); the long-nosed potoroo (Potorous tridactylus) Vulnerable (EPBCA), Threatened (FFGA); the swamp antechinus (Antechinus minimus maritimus) – Vulnerable (EPBCA), Threatened (FFGA); the white-footed dunnart (Sminthopsis leucopus) – Threatened (FFGA). Long term (1975 -2020) research programs of the ecology and biodiversity of the heathy woodlands of the eastern Otways have been led by Dr Barbara Wilson (Deakin University). The work has concentrated on how species and ecosystems respond to threats such as fire, climate change, and fragmentation. The research on native mammals represents one of the longest mammal datasets in Australia. There have been major declines in biodiversity, particularly for native mammals and vegetation communities. Mammal declines occurred post wildfire (“Ash Wednesday” 1983), and due to fragmentation, vegetation degradation from Phytophthora cinnamomi infestation and declining rainfall. Mammal declines Research programs have assessed the distribution, habitat preferences, diet and population ecology of threatened species such as the New Holland Mouse Pseudomys novaehollandiae. The species decline at landscape and local levels has been studied across Victoria). We established a successful captive breeding colony and trial reintroductions in the eastrn Otways. The work has resulted in the listing of P. novaehollandiae as endangered species (FFG Act 1988, EPBC Act 1999) establishment of the New Holland Mouse Recovery Team and production of an Action Statement. Similar research has been undertaken on the marsupial Swamp antechinus Antechinus minimus including reproduction and ecology of the species and the impacts of fragmentation and fire. The work has resulted in the listing of A. minimus as an endangered species under the EPBC Act (TSSC 2013). The research has resulted in strong evidence of the impacts of climate change on these threatened species in the eastern Otways. Significant population declines of the Swamp antechinus have been recorded during periods of below-average rainfall and drought, especially during the ‘millennium drought’ (1996–2010) where much of the south-east of Australia experienced persistent drought (CSIRO and Australian Bureau of Meteorology 2015). Maximum population densities occurred following the highest total annual rainfall (901 mm) recorded for two decades, and significant density declines were measured during periods of below-average rainfall and drought 1 LC EPC Inquiry into Ecosystem Decline in Victoria Submission 449 (2001–07). The impact of rainfall on the species is considered to result from bottom-up increases or declines in productivity of vegetation and associated dietary resources, particularly moth larvae and beetles. The New Holland mouse has also been found to be significantly influenced by rainfall, exhibiting a population irruption following six years of above-average rainfall and a precipitous decline to site extinction during subsequent drought. The decline was predominantly related to loss of adults before and during breeding seasons, together with an apparent decrease in juvenile survival. The response of this omnivore to high rainfall was mediated through increased productivity and rainfall decline resulted in resource depletion and population decline. Recent work led by Wilson (2013 to 2020) has revealed severe declines of threatened species in the eastern Otways (New Holland mouse, Swamp antechinus), together with significant declines of total small mammal communities across the landscape (Wilson et al. 2017, 2018, 2020). The New Holland mouse disappeared from all sampling sites since 2003 and may have been extirpated from this area and the Swamp antechinus was recorded in extremely low abundance and at few sites. The marked simultaneous decline of co-existing species was a most striking feature of recent results. In total, 67% of sites exhibited large to severe decreases in abundance and only 3% of sites had more than four species compared to 27% in earlier decades. Declines occurred following wildfire (“Ash Wednesday” 1983), and drought, with drivers likely to be multifactorial including fragmentation, vegetation degradation from Phytophthora cinnamomi infestation and declining rainfall during the Millenium drought. Comparison with mammal declines in other areas in Australia indicates that with current threats, conservation reserves in Australia/ Victoria may be failing to maintain elements of biodiversity; and mammal assemblages in Australia may be highly unstable (Wayne et al. 2017). While regional declines in the eastern Otways were substantial, a significant finding was that higher mammal abundance (two- to six-fold) and native species richness (including threatened species Swamp antechinus, Potoroo, Southern Brown bandicoot) were recorded at coastal dune sites, compared to inland sites. There is now evidence that species-rich small mammal communities are still abundant in specific areas such as sand dunes and gullies (Wilson et al. 2019, 2020). The contraction of mammals to these areas indicate that they represent significant refuges from disturbances, including drought, habitat fragmentation, fire regimes and introduced predators. More precise identification and better protection of these local refuges is crucial to maintain the mammal diversity of the region, particularly with respect to planned burning, wildfire management (strategic protection or post-fire response) and predator management. Vegetation and habitat decline Vegetation dieback caused by the plant pathogen Phytophthora cinnamomi is an EPBC Act Key Threatening Process, causing significant and permanent degradation to Australia’s biodiversity. The Phytophthora dieback National Threat Abatement Plan (NTAP) was produced as the framework to guide and coordinate limitations on the impact of the pathogen (Commonwealth of Australia 2018a). In Victoria the requirement for public land managers to address the threat of P. cinnamomi is also provided by State legislation and policy (infestation is listed twice under the FFGA 1988, and the state-wide management strategy - Department of Sustainability and Environment 2008). Three decades of work in the Otway region (Wilson, Cahill, Laidlaw, Garkaklis) has assessed the problem, and impacts on biodiversity. Diseased vegetation infected with P. cinnamomi was first observed in the eastern Otways in the 1970s and research on the impacts of the pathogen and its management have been undertaken since the 1980s. The impacts of the pathogen are severe and permanent. Heathy woodland monitored by our team from 1989 to 2015 found that the uninfested area had reduced by 83%. Significant declines in total number of plant species, susceptible species, cover abundance of grass trees; and an increase in disease resistant species has occurred. There were significant impacts on small mammals. The mean number of species and mammal captures were significantly lower in post-disease areas and captures of species were less frequent in diseased vegetation. Radiotracking of marsupials to grasstrees showed their significance for providing cover and nest sites and loss of grasstree cover due to Phytophthora dieback impacts severely on fauna that utilise them. The impact on Phytophthora dieback on mammal populations is a critical factor in developing a feasible approach to conserving mammals of the Otways Region. Further there have been major impacts on fungal diversity resulting in food availability of mycophaphagous 2 LC EPC Inquiry into Ecosystem Decline