Corresponding author: Craig G. Morley ( craig.morley@toiohomai.ac.nz ) Academic editor: Marie-Caroline Lefort
© 2017 Craig G. Morley, James Broadley, Robin Hartley, David Herries, Duncan MacMorran, Ian G. McLean.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Morley CG, Broadley J, Hartley R, Herries D, McMorran D, McLean IG (2017) The potential of using Unmanned Aerial Vehicles (UAVs) for precision pest control of possums (Trichosurus vulpecula). Rethinking Ecology 2: 27-39. https://doi.org/10.3897/rethinkingecology.2.14821
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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 (Trichosurusvulpecula) 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.
New Zealand, pest control, forest, Predator-free 2050
Remotely Piloted Aerial Systems (RPAS) or Unmanned Aerial Vehicles (UAVs) are affordable, have miniaturised GPS receivers with sophisticated navigational capability, and are able to provide accurate high-tech remote sensing imagery (
UAVs are routinely being used to: estimate tree crown diameters, tree fall and canopy openness (
New Zealand’s landscape (26.8 million ha) is diverse, with glaciers, fiords, rugged mountains, vast rolling alluvial plains, volcanic plateaus, geothermal zones and over 15,000 kms of coastline. Viewed aerially, New Zealand is a mosaic of natural forest managed mainly by the Department of Conservation (DOC), commercial plantation forests, agricultural land (with numerous small shelterbelts and bush remnants predominantly in steep gullies), lakes, rivers, small reserves, and urban areas. Ownership and administration of this fragmented landscape is equally fragmented, involving numerous landowners and councils, multiple land management practices, and a wide range of views about the need for and value of pest management.
About 10 million ha of land in New Zealand is already under active pest management for a variety of conservation, agricultural and economic reasons (
Most of the more difficult and remote terrain is managed aerially by broadcasting 1080 (sodium fluoroacetate) to control pests (
Many current pest control methodologies are limited in scope. For example, the control methods used on islands or isolated locations cannot be deployed on many parts of the mainland for social and ecological reasons (
The Department of Conservation manages about 8.6 million hectares for the Crown (
Other issues affecting sustainability of pest management include a requirement to obtain consents to undertake poisoning operations in some areas and cultural issues in relation to resource ownership by indigenous Māori (
Despite the enormous investment and ongoing pest control work, many parts of New Zealand still receive little or no pest control including many commercial and private forests, agricultural land with patches of bush/forest, localised reserves, and alpine areas. These areas may be geographically inaccessible, have low pest numbers, or have restricted access, and can support reservoir pest populations when pest control is undertaken nearby. Unfortunately, the large-scale pest management programmes run by organisations such as DOC or TBfree NZ (
New Zealand is an acknowledged leader in the development and application of pest management methods, for example, to protect biodiversity or eliminate TB (
Realistically, the reliance on thousands of trap-lines and aerially bombarding some large remote areas with 1080 every few years (
Detection of foliage damage using hyperspectral signatures is now achievable and could be used to enable rapid detection of pest activity (
Currently, 1080 is the only toxin registered for aerial application. Because of the controversy surrounding 1080 (
While toxins are not always welcome, targeted methodologies could allay fears by enabling precision delivery of baits or kill traps.
After large-scale aerial operations, small remnant populations can be extremely costly to mop up using ground-based methods (
Although a myriad of applications have been suggested for UAVs, several challenges remain. Limitations to operational use include payload capacity, flight-time restrictions, weather, civil aviation authority (CAA) regulations, and legal constraints. Nevertheless, emerging solutions include user-friendly aerial platforms, larger machines enabling larger payloads, longer flight times, and built-in transponders meaning that pilots no longer need line of sight (
The requirement for line of sight flying is still one of the biggest barriers, especially for flight operations over forests where maintaining visual contact can be difficult. In order to carry out operations beyond visual line of sight (BVLOS), the more advanced 102 certification can be granted by New Zealand’s CAA if an operator can manage the high level of safety and risk (
We suggest that UAVs could genuinely revolutionise pest management. Integrated technologies have recently been applied with great effect in New Zealand, such as use of UAVs mounted with thermal cameras to detect hot spots on the Port Hills in Christchurch during a serious fire event (
If New Zealand is to become predator–free, then all of New Zealand requires pest control, including gullies, steep slopes, commercial forests, small parks and reserves (both private and public). To achieve this predator-free aspiration, pest control cannot be based on affordability, biodiversity protection and TB control. Operationally, UAVs provide substantial cost and time-saving advantages over larger conventional aircraft and ground-control methods. They can fly to designated sites using pre-programmed GIS coordinates in a fraction of the time it would take a person placing traps or bait stations on the ground. Delivering baits in precise loads to specific sites using small versatile UAVs could transform pest control. Further, UAVs are easily transportable, especially to remote locations such as small offshore islands or steep gullies in broken terrain. We believe a directed and targeted approach using UAVs has the potential to significantly reduce pest control costs while improving effectiveness. Without such genuinely novel approaches, predator-free New Zealand will remain an unachievable dream.
Author contribution: CGM, developed the concept and designed the manuscript: 65%; JB, RH and IM provided key information and helped revise the manuscript, 10% each; and DH and DM provided key intellectual support 2.5% each.
Authors | Contribution | ACI |
---|---|---|
CGM | 0.65 | 9.286 |
JB | 0.1 | 0.556 |
RH | 0.1 | 0.556 |
IM | 0.1 | 0.556 |
DH | 0.025 | 0.128 |
DM | 0.025 | 0.128 |
We thank Linton Winder and two anonymous reviewers for their feedback and comments on the manuscript.