DOI: 10.5061/dryad.70rxwdc2m
title: Cost-effective portfolio allocation across quarantine, surveillance and eradication using info-gap theory

description: Biosecurity activities primarily include pre-border and border quarantine,
 post-border surveillance and post-border eradication. Budget allocated to
 quarantine and surveillance activities ultimately influence the
 expenditure and success rate of eradication campaigns. Optimal portfolio
 allocation examined in previous research is susceptible to potential
 severe uncertainties existing in ecology and in the behaviour of invasive
 species itself. These uncertainties, together with a limited budget, make
 it difficult for decision makers to allocate the total management budget
 to each biosecurity activity in a robust manner. Info-gap decision theory
 is applied to model the severe uncertainty in invasive species management,
 and robust optimize the total management cost. This research shows that
 using a combination of pre-border and border quarantine (to reduce the
 incursion probability) and post-border surveillance (to enable early
 detection and rapid response), enables decision makers to be more robust
 to potential uncertainty. Further, it is reported that investment in
 quarantine that is more cost-effective should outweigh that in
 surveillance, in line with precautionary principle. Increasing the
 estimated population threshold for surveillance detection also gains more
 robustness. Synthesis and applications: Portfolio allocation options
 developed in this research provide decision makers with a way to manage
 the invasive species spatially, cost-effectively, and confidently by
 allocating the total management budget in a robust manner. The methods
 outlined in this research can not only be applied to invasive species, but
 also the conservation of endangered species that are constrained by severe
 uncertainty in ecological modelling and limited resources.
description: Input data, provided by Chevron
 Australia, can be found in excel file 'matlab+totalcost.xlsx'.
 Code file '<strong>Figure
 2</strong>' is used to generate Fig 2 in the manuscript,
 indicating the relationship between robustness and total budget limit,
 with the optimal portfolio
 allocation between quarantine and surveillance applied. This part also
 presented the effects of altering the estimated population threshold on
 the robustness. Code files
 '<strong>Figure 3</strong>' and
 '<strong>Figure 4</strong>' are used to generate Fig
 3 and Fig 4 in the manuscript. This part was to evaluate the robustness of
 various portfolio allocation options, with estimated population threshold
 set at 8 and 20 respectively.  All the exploratory analyses of
 robustness function in the manuscript have been conducted in MATLAB R2018b
 (MathWorks 2018).
description: # Title of Dataset: Cost-effective portfolio allocation across quarantine,
 surveillance and eradication using info-gap theory We have submitted our
 raw data (**matlab+totalcost.xlsx**), MATLAB script (**Figure 2.m, Figure
 3.m, Figure 4.m**). ## Description of the Data and file structure In the
 excel file **'matlab+totalcost.xlsx':** *Surface Info:* The
 potential entry points for an Asian house gecko (AHG) incursion on Barrow
 Island (BWI), Western Australia. Zone 0 is the buffer area at Material
 Offloading Facility (MOF) (i.e. X-Blocs area). Zone 1 is the area with the
 highest occupancy probability, where the majority of the surveillance
 budget should be spent. Zone 2 is the secondary introduction area (100 m
 buffer area around Zone 1) and is considered the lower risk boundary for a
 species dispersing out of Zone 1. Zone 3 is the remaining island area
 where the AHG is less likely to establish prior to detection thus with no
 SSCs allocated. POF is Permanent Operating Facility; GTP is Gorgon LNG
 Plant Gorgon Liquefied Natural Gas Plant. *Entry Info:* Incursion
 probability to each location on Barrow Island, Western Australia. 
 *Survival Info:* Survival probability in each zone (Z0, Z1, Z2) at each
 location on Barrow Island, Western Australia *SSC Info:* Surveillance
 System Component (SSC) (i.e. a range of methods used to detect a potential
 AHG) are used for surveillance detection. This excel illustrates the sigma
 (𝜎), footprint and unit cost of various SSCs at different locations and
 zones on Barrow Island, Western Australia. Sigma is the detection
 probability of SSCs given invasive species present in the
 footprint. Footprint is the area in which an AHG can be detected with a
 single unit of SSC. Cost is per unit of SSCs. *Quarantine:* Quarantine
 components units being used by Chevron, cost of each quarantine component,
 and total cost of all quarantine components. Definitions of the SSCs in
 this sheet: (1) Mobe-mote: The Mobe-mote is an adhesive siliconised paper
 that has been manufactured as an aid to trapping *Hemidactylus
 frenatus *around problem, high-risk areas. (2) Go gecko - Spray: A
 repellant designed to combat geckos wherever they hide. (3) Go gecko -
 Tech: A suite of advanced biosecurity tools designed to detect and monitor
 non-indigenous species. (4) EARs (net-worked): Environmental Acoustic
 Recognition Sensors (EARS). A networked device that can detect the
 multiple chirp calls of *Hemidactylus frenatus*. This device is powered by
 solar panels and provides notifications to an end user via a user
 interface when a suspect call is detected. One SSC equals 1 EAR recording
 for 1 night (5) S.survey: Structured surveys. A formal biological survey
 of an area looking for signs of nonindigenous vertebrate or invertebrate
 species. Signs may include tracks, scats, auditory calls, burrows, eye
 shine, eggs or individuals. One SSC is approximately 5,000 m2 area.
 (6) TEU(vessel&Freight): A Twenty-foot Equivalent Unit (TEU) is a
 standard measure for cargo container capacity, used to quantify and manage
 shipping and freight logistics. Code file '**Figure 2**':
 This script was used to generate Fig 2 in the manuscript, indicating the
 relationship between robustness and total budget limit, with the optimal
 portfolio allocation between quarantine and surveillance applied. This
 part also presented the effects of altering the estimated population
 threshold on the robustness. Code files '**Figure
 3**'/'**Figure 4**': This script was used to generate Fig
 3/Fig 4 in the manuscript. This part was to evaluate the robustness of
 various portfolio allocation options, with estimated population threshold
 set at 8 (Fig 3) and 20 (Fig 4) respectively.  ## Key Information Sources
 Input data in excel file 'matlab+totalcost.xlsx' was provided by
 Chevron Australia Pty Ltd. ## Code/Software MATLAB is required to
 run ***Figure 2.m, Figure 3.m, Figure 4.m***; the script was created using
 version R2018b (MathWorks 2018).