Cost-Effective Large-Scale Occupancy–Abundance Monitoring of Invasive Brushtail Possums (Trichosurus Vulpecula) on New Zealand’s Public Conservation Land

Gormley, Andrew M.; Forsyth, David M.; Wright, Elaine F.; Lyall, John; Elliott, Mike; Martini, Mark; Kappers, Benno; Perry, Mike; McKay, Meredith

doi:10.1371/journal.pone.0127693

Cited by 7 publications

(16 citation statements)

References 45 publications

(54 reference statements)

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“…New Zealand is an acknowledged leader in the development and application of pest management methods, for example, to protect biodiversity or eliminate TB (Gormley et al 2015;Holmes et al 2015;Jones et al 2016). Recently, the New Zealand government announced an ambitious policy to be "Predator-free New Zealand" by 2050.…”

Section: Predator Free 2050mentioning

confidence: 99%

“…Possums are known to selectively defoliate tree species including kamahi (Weinmannia racemosa), northern rātā (Metrosideros robusta), kohekohe (Dysoxylum spectabile), tree fuchsia (Fuchsia excorticata), and other plant species (Pekelharing et al 1998;Sweetapple and Nugent 1999;Gormley et al 2012;Holland et al 2013). Pests also target young pine (Pinus radiata) trees in commercial plantations (Clout 1977;Keber 1983).…”

Section: What Uavs Can Bring To the Picture?mentioning

confidence: 99%

“…After large-scale aerial operations, small remnant populations can be extremely costly to mop up using ground-based methods (Sweetapple and Nugent 2011;Gormley et al 2015;Holmes et al 2015). UAVs dropping toxin on remnant nearby populations soon after these large-scale aerial operations could also be used to maintain suppression and minimise reinvasion by possums and rats, which will inevitably appear in the overall control area (Armstrong et al 2014Cowan 2016;Griffiths and Barron 2016;Sweetapple et al 2016).…”

Section: What Uavs Can Bring To the Picture?mentioning

confidence: 99%

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The potential of using Unmanned Aerial Vehicles (UAVs) for precision pest control of possums (Trichosurus vulpecula)

Morley¹,

Braodley²,

Hartley³

et al. 2017

ReEco

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Unmanned Aerial Vehicles (UAVs) and remote image sensing cameras have considerable potential for use in pest control operations. UAVs equipped with remote sensing cameras could be flown over forests and remnant bush sites, particularly those not currently receiving any pest control, to record the unique spectral signature of the vegetation and to detect the presence of possums (Trichosurus vulpecula) and the damage they cause. UAVs could then be deployed to precisely distribute either toxins or kill traps to these identified locations. Predator-free 2050 is an ambitious policy announced by the New Zealand Government where several pests, including possums, are to be eradicated by the year 2050. In order to achieve this goal, pests must be identified, targeted and controlled, requiring creative and novel ideas. UAVs provide flexibility, can fly in remote and difficult terrain, and are considerably cheaper to purchase and operate than the planes and helicopters currently used in conventional aerial pest control operations. Current challenges associated with UAVs include payload capacity, battery limitations, weather, and flying restrictions. However, these issues are rapidly being resolved with sophisticated technological advances and improved regulations. A directed and targeted approach using UAVs is an additional and novel tool in the pest management toolbox that could significantly reduce pest control costs, cover inaccessible areas not receiving any pest management, and will help New Zealand advance towards its predator-free aspiration by 2050.

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Section: Predator Free 2050mentioning

confidence: 99%

Section: What Uavs Can Bring To the Picture?mentioning

confidence: 99%

Section: What Uavs Can Bring To the Picture?mentioning

confidence: 99%

See 1 more Smart Citation

The potential of using Unmanned Aerial Vehicles (UAVs) for precision pest control of possums (Trichosurus vulpecula)

Morley¹,

Braodley²,

Hartley³

et al. 2017

ReEco

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“…The two key indicators of possum status and trend in the BMRS are occupancy and abundance (Allen et al 2013;Gormley et al 2015). Occupancy can be defined as the proportion of sites used by a taxon and is estimated from detection/non-detection data collected at sites (MacKenzie et al 2002(MacKenzie et al , 2006.…”

Section: Introductionmentioning

confidence: 99%

“…Abundance is the number of individuals present within an area of interest, but is difficult to estimate accurately and precisely for animals (Williams et al 2002). Leg-hold traps and pellet detection/non-detection have been used to monitor possums in the BMRS (Gormley et al 2015;Fig. 1a).…”

Section: Introductionmentioning

confidence: 99%

Calibrating brushtail possum (Trichosurus vulpecula) occupancy and abundance index estimates from leg-hold traps, wax tags and chew cards in the Department of Conservation’s Biodiversity and Monitoring Reporting System

Forsyth¹,

Perry²,

Moloney³

et al. 2018

NZ J Ecol

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Abstract:The Department of Conservation has implemented a Biodiversity and Monitoring Reporting System (BMRS) that estimates occupancy rates and relative abundances of introduced brushtail possums (Trichosurus vulpecula) at a representative sample of sites on public conservation land. Leg-hold traps have been used to monitor possums in the BMRS, but wax tags and chew cards have logistical and financial advantages over traps. If possum occupancy rate and/or abundance index estimates differ depending on which of the three methods are used, then correction of the estimates would be required for valid comparisons. We sampled possum occupancy rates and relative abundances using leg-hold traps, wax tags and chew cards in the BMRS sampling design at each of 54 forest and 54 non-forest sites. Possum occupancy rates estimated using each of the three detection methods were similar and hence do not require correction. Median possum abundance index values estimated from traps were lower than those estimated from wax tags and chew cards in forest, but were similar to those from wax tags in non-forest. Calibration is therefore required if possum abundance index values from either chew cards or wax tags are to be validly compared with trap catch abundance index values. We used a zeroinflated negative binomial (ZINB) model to calibrate the chew card and wax tag abundance indices with the trap catch abundance index. The ZINB model allowed us to account for structural zeros (i.e. possums were not present and therefore cannot be detected) and non-structural zeros (i.e. possums were present, but not detected by a particular method). The relationship between possum abundance index estimates from chew cards and leg-hold traps was better calibrated than that between wax tags and leg-hold traps, with the latter particularly poor in non-forest habitat. We therefore conclude that chew cards, rather than wax tags, should replace leg-hold traps for monitoring possum occupancy rates and relative abundances in the BMRS. Our ZINB model can be used to correct chew card abundance index values for valid comparison with previous trap catch abundance index values estimated using the BMRS design.

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Implementing integrated measurements of Essential Biodiversity Variables at a national scale

Bellingham

Richardson

Gormley

et al. 2020

Ecol Sol and Evidence

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1. There is a global need for observation systems that deliver regular, timely data on state and trends in biodiversity, but few have been implemented, and fewer still at national scales. We describe the implementation of measurement of Essential Biodiversity Variables (EBVs) on an 8 km × 8 km grid throughout New Zealand, with multiple components of biodiversity (vegetation, birds, and some introduced mammals) measured simultaneously at each sample point. 2. Between 2011 and 2017, all public land was sampled nationally (ca. 1,350 points) and some private land (ca. 500 points). Synthetic appraisals of the state of New Zealand's biodiversity, not possible previously, can be derived from the first measurement of species distribution, population abundance, and taxonomic diversity EBVs. 3. Native bird counts (all species combined) were about 2.5 times greater per sample point in natural forests and shrublands than in non-woody ecosystems, and native bird counts exceeded those of non-native birds across all natural forests and shrublands. 4. Non-native plants, birds, and mammals are invasive throughout, but high-rainfall forested regions are least invaded, and historically deforested rain shadow regions are most invaded. 5. National reporting of terrestrial biodiversity across New Zealand's public land is established and becoming normalised, in the same manner as national and international reporting of human health and education statistics. The challenge is extending coverage across all private land. Repeated measurements of these EBVs, which began in 2017, will allow defensible estimates of biodiversity trends. K E Y W O R D S biological invasions, grid-based sampling, non-native birds, state and trend monitoring, systematic biodiversity assessment This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Cost-Effective Large-Scale Occupancy–Abundance Monitoring of Invasive Brushtail Possums (Trichosurus Vulpecula) on New Zealand’s Public Conservation Land

Cited by 7 publications

References 45 publications

The potential of using Unmanned Aerial Vehicles (UAVs) for precision pest control of possums (Trichosurus vulpecula)

The potential of using Unmanned Aerial Vehicles (UAVs) for precision pest control of possums (Trichosurus vulpecula)

Calibrating brushtail possum (Trichosurus vulpecula) occupancy and abundance index estimates from leg-hold traps, wax tags and chew cards in the Department of Conservation’s Biodiversity and Monitoring Reporting System

Implementing integrated measurements of Essential Biodiversity Variables at a national scale

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