CSIRO Submission 18/641
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• CSIRO Submission 18/641 The impact of feral deer, pigs and goats in Australia Senate Standing Committee on Environment and Communications November 2018 Enquiries should be addressed to: Main Submission Author(s): Dr Grant Farrell Peter Caley, Senior Research Scientist, Data61 CSIRO M inisterial and Parliamentary Liaison and GPO Box 1700 Canberra 2601 Dr Justin Perry, Research Scientist, Land & Wat er Table of Contents Table of Contents .............................................................................................................................................. 2 Executive Summary ........................................................................................................................................... 3 Introduction ....................................................................................................................................................... 4 CSIRO response to the Terms of Reference (ToR) ............................................................................................. 5 a) the current and potential occurrence of feral deer, pigs and goats across Australia ........................... 5 b) the likely and potential biosecurity risks and impacts of feral deer, pigs and goats on the environment, agriculture, community safety and other values ................................................................... 8 c) the effectiveness of current state and national laws, policies and practices in limiting spread and mitigating impacts of feral deer, pigs and goats ......................................................................................... 11 d) the efficacy and welfare implications of currently available control and containment tools and methods, and the potential for new control and containment tools and methods ................................... 13 e) priority research questions .................................................................................................................. 15 f) the benefits of developing and fully implementing national threat abatement plans for feral deer, pigs and goats.............................................................................................................................................. 17 g) any other related matters ................................................................................................................... 17 References ....................................................................................................................................................... 18 CSIRO submission 18/641 2 November 2018 Executive Summary Deer are emerging as a potentially major wildlife management issue that are anticipated to affect much of Australia, as together Australia’s six species can colonise most Australian habitats. The environmental impacts of deer are not well known. This is a critical information gap that may hamper the development of effective management responses and potentially hinder broader public acceptance of control actions should they be required. The limited ability of current control options to reduce deer populations in all but open environments means eradication is likely to be infeasible except, perhaps, in small and isolated locations. Management of deer is made complex by many competing interests. Thus a national threat abatement plan for wild deer should (1) enable strategic planning, prioritisation and coordination of research and management actions among researchers, key interest groups and government agencies, (2) provide explicit performance criteria which allow researchers and responsible government agencies to measure and report on progress against measureable targets, and (3) guide and facilitate research investment. Feral pigs are a more established, well known pest species than deer, with a considerable amount of existing knowledge relating to impacts and management options encapsulated in a National Threat Abatement Plan. They are, however, still expanding their range and new impacts are emerging. Lived management experience indicates that traditional approaches to population control that rely on recurrent resourcing are not sustainable, and that new approaches are required. The impacts of pigs are often on highly localised assets (e.g. crops, wetlands, turtle rookeries). This suggests an asset-protection focussed approach to minimising feral pig impacts may be a more viable solution. Preventing pig access to such localised resources may also act as a form of population regulation. This approach is consistent with the strategic intent of the current Threat Abatement Plan. CSIRO is using state-of-the-art tracking devices and trialling detection sensors to explore how feral pigs use their environment and how restricting resources might work in practice to develop automated asset- protection focussed responses. Lands of Northern Australia that are managed by Aboriginal and Torres Strait Islander communities have experienced a disproportionate impact from feral pigs, but those communities are also deriving benefits from them. Involving local groups in managing the impacts of feral pigs appears to offer a potentially more effective and sustainable approach, and CSIRO is undertaking research in this area. Feral goats remain a serious threat to biodiversity over large tracts of Australia’s rangelands. Methods of control are well known and highly effective if implemented well. However progress in mitigating impacts has been limited and the range of feral goats is continuing to expand in places. It is not clear whether a national threat abatement plan can effectively address this, as economic and social interests in feral goat management are at odds with minimising environmental impact. CSIRO is in the process of developing a range of tools and technologies for more efficient, effective and feasible management of the three ungulate types. We have identified research gaps that include opportunities for: • Better monitoring of species impacts and efficacy of control programs, • Socio-economic research — human geography of feral animal management, • Determining underlying resource drivers of feral animal populations, and • Spatial and temporal mapping of resources and populations. CSIRO submission 18/641 3 November 2018 Introduction CSIRO welcomes the opportunity to provide input to the Senate Standing Committee on Environment and Communications’ inquiry into the impact of feral deer, pigs and goats in Australia. Recent CSIRO research in relation to feral animals has focused on management and ecological impacts, particularly of feral pigs (e.g. Caley 2008; Caley and Welvaert 2018; Murray et al. 2015; see also https://www.csiro.au/en/Research/LWF/Areas/Ecosystems-biodiversity/Managing-landscapes-for- biodiversity/Feral-animals/Tracking and https://www.csiro.au/en/Research/LWF/Areas/Ecosystems- biodiversity/Managing-landscapes-for-biodiversity/Feral-animals) and ecological relationships between predation and deer (e.g. Forsyth, Caley et al. 2018a; Forsyth et al. 2018b). CSIRO’s submission provides an overview of relevant science against the Terms of Reference for the inquiry and CSIRO would be pleased to discuss any aspect of this submission with the Committee. CSIRO submission 18/641 4 November 2018 CSIRO response to the Terms of Reference (ToR) a) the current and potential occurrence of feral deer, pigs and goats across Australia General considerations Populations of herbivores colonising new ranges typically undergo dramatic growth, followed by a population crash, then partial recovery to a lower density that fluctuates based on the seasons – a phenomenon termed an ungulate ‘irruption’. The phenomenon was first described and explained by the late CSIRO scientist Graeme Caughley (Caughley 1970, 1987), and is consistently repeated when herbivores are introduced to or invade new ranges (Forsyth and Caley 2006). The relevance here is that the impact of invading populations tends to be highest in the early phases as the invading populations approach their peak, and highly palatable food resources are exhausted. As an example, Australia’s rangeland sheep population reached peak numbers near the end of the 19th century, only to crash during the Federation drought. Populations never recovered to anywhere near the peak levels, as the palatable plant species were replaced within the vegetation mix with those less palatable. It was during this period of high sheep and rabbit numbers, in conjunction with the arrival of foxes, that most of Australia’s now extinct mammal fauna were seen for the last time (Johnson 2006). Feral pig, wild deer and goat populations introduced to new ranges exhibit similar irruptive behaviour, with the time from introduction to peak density as long as several decades (Forsyth and Caley 2006). For example, peak densities of feral pigs were seen in many regions of NSW in the early 1970s (e.g. Giles 1980), whereas in East Arnhem Land peak densities didn’t occur until the late 1990s early 2000s as these populations were founded much more recently (Caley 1997). Deer are yet to reach peak densities in much of their current range (Moriarty 2004). Deer Current distribution The current distribution of wild deer in south-eastern Australia is more an artefact of locations of escape and liberation than climate and habitat suitability. Fallow (Dama dama); red (Cervus elaphus); rusa (Cervus timorensis); sambar (Cervus unicolour); chital (Axis axis) and hog (Axis porcinus) deer have established wild populations in eastern Australia (Moriarty