Surveillance protocols for management of invasive plants: modelling Chilean needle grass (Nassella neesiana) in Australia

Authors

  • J. C. Fox,

    Corresponding author
    1. Department of Forest and Ecosystem Science, Melbourne School of Land and Environment, The University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Vic. 3121, Australia
    2. Geographical Sciences and Planning, The University of Queensland, St Lucia 4067, Qld, Australia
    3. CRC for Australian Weed Management
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  • Y. M. Buckley,

    1. The Ecology Centre, School of Integrative Biology, University of Queensland, St Lucia 4067, Qld, Australia
    2. CSIRO Sustainable Ecosystems, Queensland Bioscience Precinct, 306 Carmody Rd, St Lucia 4067, Qld, Australia
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  • F. D. Panetta,

    1. CRC for Australian Weed Management
    2. Department of Primary Industries and Fisheries, Alan Fletcher Research Station, Sherwood 4075, Qld, Australia
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  • J. Bourgoin,

    1. Geographical Sciences and Planning, The University of Queensland, St Lucia 4067, Qld, Australia
    2. CRC for Australian Weed Management
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  • D. Pullar

    1. Geographical Sciences and Planning, The University of Queensland, St Lucia 4067, Qld, Australia
    2. CRC for Australian Weed Management
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*J. C. Fox, Department of Forest and Ecosystem Science, Melbourne School of Land and Environment, The University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Vic. 3121, Australia.
E-mail: jcfox@unimelb.edu.au.

Abstract

Aim  To develop a surveillance support model that enables prediction of areas susceptible to invasion, comparative analysis of surveillance methods and intensity and assessment of eradication feasibility. To apply the model to identify surveillance protocols for generalized invasion scenarios and for evaluating surveillance and control for a context-specific plant invasion.

Location  Australia.

Methods  We integrate a spatially explicit simulation model, including plant demography and dispersal vectors, within a Geographical Information System. We use the model to identify effective surveillance protocols using simulations of generalized plant life-forms spreading via different dispersal mechanisms in real landscapes. We then parameterize the surveillance support model for Chilean needle grass [CNG; Nassella neesiana (Trin. & Rupr.) Barkworth], a highly invasive tussock grass, which is an eradication target in south-eastern Queensland, Australia.

Results  General surveillance protocols that can guide rapid response surveillance were identified; suitable habitat that is susceptible to invasion through particular dispersal syndromes should be targeted for surveillance using an adaptive seek-and-destroy method. The search radius of the adaptive method should be based on maximum expected dispersal distances. Protocols were used to define a surveillance strategy for CNG, but simulations indicated that despite effective and targeted surveillance, eradication is implausible at current intensities.

Main conclusions  Several important surveillance protocols emerged and simulations indicated that effectiveness can be increased if they are followed in rapid response surveillance. If sufficient data are available, the surveillance support model should be parameterized to target areas susceptible to invasion and determine whether surveillance is effective and eradication is feasible. We discovered that for CNG, regardless of a carefully designed surveillance strategy, eradication is implausible at current intensities of surveillance and control and these efforts should be doubled if they are to be successful. This is crucial information in the face of environmentally and economically damaging invasive species and large, expensive and potentially ineffective control programmes.

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