LC EPC Inquiry into Ecosystem Decline in 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 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 assemblage in the area consists of 15 small to medium-sized mammal species. The include threatened species listed federally (EPBCA 1999) and in Victorian (FFGA 1988): the ( novaehollandiae) – Vulnerable (EPBCA), Threatened (FFGA); the Southern Brown (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 . 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 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 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, ) 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 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 in Victoria Submission 449 endangered mammal species including the New Holland mouse; southern brown bandicoot, swamp antechinus and long- nosed Potoroos. Overall ecosystem health is thus threatened in this highly biodiverse ecosystem.

Increases in recreational use, favourable environmental conditions and (unexplained) movement of the pathogen between sites means that remaining pristine areas in the Otway Ranges are under immediate threat of significant degradation from Phytophthora dieback. Continued spread of the pathogen and the expression of the disease elsewhere in the Otway region (e.g. Carlisle Heath of the central Otways) also poses a serious threat to EPBCA 1999 protected species; including Tall Astelia, southern brown bandicoot and the, swamp antechinus.

Measures to restore habitats and populations of threatened and endangered species

Under a drying climate the direct impacts of rainfall decline on mammals will continue. However, management of other threats may increase species resilience. Burning to provide optimal successional vegetation, protection of refuges, and predator control are priorities. Several threats identified in the eastern Otways are likely to have complex synergistic interactions on the population dynamics of mammals. For example, wildfire or fuel-reduction management burns during drought conditions increase the risk of extirpation of small fragmented populations and decrease recovery opportunities. The recent evidence that the impacts of introduced predators on mammals are more severe in burnt areas (Hradsky et al. 2017) indicates that the impact of predators will be exacerbated under increased burning regimes. There is a need to understand further how these factors interact in order to develop recovery and management plans under predicted climate change. a) Identification and protection of fauna refuges

Work is currently being undertaken to identify mammal fauna habitat refuges across the Otway Ranges utilising site topographical information, and satellite remote-sensed vegetation productivity data to characterise the refuge sites (Wilson et al. 2018a, 2019). The projected rainfall declines over the study area under a high-carbon-emission scenario are from 25% to 45% by 2090. Irrespective of the causal factors of mammal declines, more precise identification and better protection of refuges is considered crucial to increase resilience of mammal species and communities of the region, particularly with respect to wildfire, fuel-reduction burning and predator management Wilson et al. 2017b, 2018a). The sand dune refuges and gullies should certainly be a focus of predator control, particularly after fire. b) Provision of supplementary built refuges

Biodiversity conservation is increasingly challenged by the intensification of large-scale, synergistic threats. Identifying, protecting, or even artificially creating places that provide refuge for biodiversity is a key strategy that managers use to protect threatened species in the face of these threatening processes. There is evidence that new methods for conserving threatened fauna in post-fire environments are needed if further are to be prevented. Providing supplementary refuges in post-fire environments is an exciting new approach that could reduce predation rates and increase population persistence post-fire. A current Deakin project “Conserving threatened mammals in the face of fire and predation” aims is to assess how ground mammal fauna respond to supplementary refuges (wire tunnels) in post-fire environments in heathy woodlands in the Otway Ranges (Wilson, Doherty, Garkaklis, Driscoll 2018 -2021). The objectives are to determine if the provision of supplementary refuges increases individual survival and population size of mammals post-fire; and whether surviving animals move out of burnt areas into unburnt patches post-fire, and how they interact with supplementary refuges.

Darcy Watchorn, a Deakin PHD candidate, has established artificial refuges immediately post-fire in one landscape burnt in autumn 2019. Surveys of pre-fire diversity and abundance of small mammals were conducted six- and three- months pre-fire, immediately post-fire and six months post-fire. Cameras are set within the refuges and between refuges to track mammals. Preliminary results have identified a number of bird species and small marsupials and utilising the refuges. Another refuge experimental site will be established in the eastern Otways in 2020, and one sites has been established in collaboration with DELWP following a fire management burn in the Carlisle heathlands.

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LC EPC Inquiry into Ecosystem Decline in Victoria Submission 449 c) Captive breeding, reintroductions of threatened species

The New Holland mouse has now been nominated for reclassification to Endangered due to the magnitude of nationwide reduction in capture per unit (up to 99%) and average national reduction in population size (> 50%), over the last 10 years (Threatened Species Nomination 2019). As recent studies and surveys have failed to find New Holland mouse in the eastern Otways the future of the species likely is dependent on captive breeding and reintroductions. This would likely involve reintroductions in predator free fenced areas that are managed for the purpose of New Holland mouse conservation. Successful captive breeding of the New Holland mouse was conducted previously (Lock 2005) and trial reintroductions were undertaken with limited success in 2002. Potentially suitable habitat where reintroduction sites would be located has also been identified (Wilson et al. 2015).

The Swamp antechinus has been listed as Vulnerable (EPBCA 1999) (TSSC 2016). However there is now strong evidence of continued decline of populations, extent of occurrence and area of occupancy in the eastern Otways. There is an opportunity to mitigate current threats and increase resilience of the species with appropriate management such as implementation of suitable fire regimes, establishment and protection of refuges and ecological linkages and control of predators. Implementation of burning regimes to ensure access to appropriate age classes need to be given high priority. Providing key refuge sites can buffer a species from several threats. It is crucial that conservation efforts focus on refuge areas for Swamp antechinus. It is recommended that refuge areas such as coastal dunes be identified across the landscape, utilising current or improved habitat models and remote-sensing techniques, and that intensive management (protection from inappropriate fire, control of rabbits, introduced predators) be implemented as a priority. d) Management of Phytophthora dieback

The extent of occurrence and location of significant uninfested areas are unknown in the eastern Otways. Increases in recreational use, favourable environmental conditions and (unexplained) movement of the pathogen between sites means that remaining pristine areas are under immediate threat of significant degradation from Phytophthora dieback. Recent work has measured or observed significant disease expression and declines of X. australis in large areas of Grass-tree dominated heathlands (Wilson and Garkaklis 2019 a, b). If this disease epidemic is permitted to progress and spread, the eventual loss of this vegetation will lead to significant and permanent impacts on biodiversity, including loss of susceptible protected (EPBCA 1999) species e.g. Tall Astelia, New Holland mouse; Southern Brown Bandicoot, Swamp Antechinus.

Currently, there are no proven methods to eradicate P. cinnamomi from a site or to prevent autonomous spread of the pathogen. As a result major management objectives are to minimise the spread to uninfested sites by restricting access implementing hygiene procedures when entering and exiting uninfested sites, and to alleviate the impact at infested sites, by application of the biodegradable fungicide phosphite, which effectively reduces or prevents infestation (Commonwealth of Australia 2018a ). Previous phosphite treatments have been found to be effective in the study area (Aberton et al., 1999; Laidlaw et al. 2003; Annett 2008).

Management approaches urgently recommended for the Otways include mapping the distribution of P. cinnamomi impacted vegetation and identifying floristically important non-diseased vegetation. It is imperative that quarantine of non-infested areas, phosphite application, track closures and vehicle wash-downs be implemented to reduce disease extension and protect the significant biodiversity of the region.

These long-term research programs were not established as monitoring programs, so were without defined condition breakpoints that would trigger management responses. There is a need to implement consistent monitoring of mammals and vegetation that provides effective measures for management.

There are many similar examples of biodiversity declines across the state, hopefully this inquiry will identify the urgent strategies and priorities required to maintain and restore these ecosystems.

Dr Barbara Wilson, Hon. Associate Professor in Ecology School of Life and Environmental Sciences Deakin University, , Australia. 4

LC EPC Inquiry into Ecosystem Decline in Victoria Submission 449 Selected references

Annett, K. (2008). Impacts of the plant pathogen P. cinnamomi (Cinnamon fungus) on fauna and ecosystem functions. Ph.D. Thesis, Deakin University, Geelong. Laidlaw, W. S., and Wilson, B. A. (2003). Floristic and structural characteristics of a coastal heathland exhibiting symptoms of Phytophthora cinnamomi infection in the eastern Otway Ranges, Victoria. Australian Journal of Botany 51, 283–293. doi:10.1071/BT02100 Laidlaw, W. S., and Wilson, B. A. (2006). Habitat utilisation by small mammals in a coastal heathland exhibiting symptoms of Phytophthora cinnamomi infestation. Wildlife Research 33, 639–649. doi:10.1071/ WR05080 Lock, M. L., and Wilson, B. A. (1999). The distribution of the New Holland mouse (Pseudomys novaehollandiae) with respect to vegetation near Anglesea, Victoria. Wildlife Research 26, 565–577. doi:10.1071/ WR97050 Lock, M., and Wilson, B. A. (2017). Influence of rainfall on population dynamics and survival of a threatened (Pseudomys novaehollandiae) under a drying climate in coastal woodlands of south-eastern Australia. Australian Journal of Zoology 65, 60–70. doi:10.1071/ZO16084 Magnusdottir, R., Wilson, B. A., and Hersteinsson, P. (2008). Dispersal and the influence of rainfall on a population of swamp antechinus (Antechinus minimus maritimus). Wildlife Research 35, 446–454. doi:10.1071/WR06156 Sale, M. G., Wilson, B. A., and Arnould, J. P. Y. (2008). Factors influencing population dynamics in island and mainland populations of swamp antechinus (Antechinus minimus; Marsupialia). Australian Journal of Zoology 56, 187–194. doi:10.1071/ZO08076 Wayne, A. F., Wilson, B. A., and Woinarski, J. C. Z. (2017b). Falling apart? Insights and lessons from three recent studies documenting rapid and severe decline in terrestrial mammal assemblages of northern, south-eastern and southwestern Australia. Wildlife Research 44, 114–126. doi:10.1071/WR16178 Wilson, B. A. (1991). The ecology of Pseudomys novaehollandiae (Waterhouse 1843) in the Eastern Otway Ranges, Victoria. Wildlife Research 18, 233–247. doi:10.1071/WR9910233 Wilson, B. A. (1996). Fire effects on vertebrate fauna and implications for fuel reduction burning and management. In ‘Fire and Biodiversity: the effects and effectiveness of fire management. Proceedings of the Biodiversity Series conference, Footscray, Melbourne, 8–9 October 1994’ Wilson, B. A., and Garkaklis, M. J. (2020). Patterns of decline of small mammal assemblages in vegetation communities of coastal south-east Australia: identification of habitat refuges. Australian Mammalogy https://doi.org/10.1071/AM20032 Wilson, B. A., Robertson, D., Moloney, D. J., Newell, G. R., and Laidlaw, W. S. (1990). Factors affecting small mammal distribution and abundance in the eastern Otway Ranges, Victoria. Proceedings of the Ecological Society of Australia 16, 379–396. Wilson, B. A., Aberton, J., and Cahill, D. (2000). The relationship between site factors and distribution of Phytophthora cinnamomi in the Eastern Otway Ranges, Victoria. Australian Journal of Botany 48, 247–260. doi:10.1071/BT98067 Wilson, B. A., Aberton, J., and Reichl, T. (2001). Effects of fragmented habitat and fire on the distribution and ecology of the Swamp Antechinus (Antechinus minimus maritimus) in the Eastern Otways, Victoria. Wildlife Research 28, 527–536. doi:10.1071/WR00016 Wilson, B. A., Aberton, J., and Lewis, A. (2003). A spatial model for predicting the presence of cinnamon fungus (Phytophthora cinnamomi) in sclerophyll vegetation communities in south-eastern Australia. Austral Ecology 28, 108–115. doi:10.1046/j.1442-9993.2003.01253.x Wilson, B. A., Millie, S., and Aberton, J. (2015). Identification of optimal habitat for the recovery and management of New Holland mouse (Pseudomys novaehollandiae) in the eastern Otways, southern Victoria. Report to Parks Victoria. School of Life & Environmental Sciences, Deakin University, Victoria. Wilson, B. A., Garkaklis, M. J., and Zhuang-Griffin, L. (2017a). Re-assessment of the status and distribution of the endangered A. minimus maritimus Swamp antechinus in the eastern Otways. Final Report to Parks Victoria. Deakin University, Victoria. Wilson, B. A., Zhuang-Griffin, L., and Garkaklis, M. J. (2017b). Decline of the dasyurid marsupial Antechinus minimus maritimusin south-east Australia: implications for recovery and management under a drying climate. Australian Journal of Zoology 65, 203–216. doi:10.1071/ZO17041 Wilson, B. A., Lock, M., and Garkaklis, M. J. (2018). Long-term fluctuations in distribution and populations of a threatened rodent (Pseudomys novaehollandiae) in coastal woodlands of the Otway Ranges, Victoria: a regional decline or extinction? Australian Mammalogy 40, 281–293. doi:10.1071/AM17036

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