Limits...
Refining Operational Practice for Controlling Introduced European Rabbits on Agricultural Lands in New Zealand.

Latham AD, Latham MC, Nugent G, Smith J, Warburton B - PLoS ONE (2016)

Bottom Line: In each case, experimental sowing via strip patterns using 10-15 kg of bait per hectare was compared with the current best practice of aerial broadcast sowing at 30-35 kg/ha.We project that strip-sowing could reduce by two thirds the amount of active 1080 applied per hectare in aerial control operations against rabbits, both reducing the non-target poisoning risk and promoting cost savings to farming operations.These results indicate that, similarly to the recently-highlighted benefits of adopting strip-sowing for poison control of introduced brushtail possums (Trichosurus vulpecula) in New Zealand, aerial strip-sowing of toxic bait could also be considered a best practice method for rabbit control in pest control policy.

View Article: PubMed Central - PubMed

Affiliation: Wildlife Ecology & Management, Landcare Research, P.O. Box 69040, Lincoln 7640, New Zealand.

ABSTRACT
European rabbits (Oryctolagus cuniculus) pose a major threat to agricultural production and conservation values in several countries. In New Zealand, population control via poisoning is a frontline method for limiting rabbit damage, with large areas commonly treated using the metabolic toxin sodium fluoroacetate ('1080') delivered in bait via aerial dispersal. However, this method is expensive and the high application rates of the active ingredient cause public antipathy towards it. To guide reductions in cost and toxin usage, we evaluated the economics and efficacy of rabbit control using an experimental approach of sowing 1080-bait in strips instead of the commonly-used broadcast sowing method (i.e. complete coverage). Over a 4-year period we studied aerial delivery of 0.02% 1080 on diced carrot bait over ~3500 ha of rabbit-prone land in the North and South islands. In each case, experimental sowing via strip patterns using 10-15 kg of bait per hectare was compared with the current best practice of aerial broadcast sowing at 30-35 kg/ha. Operational kill rates exceeded 87% in all but one case and averaged 93-94% across a total of 19 treatment replicates under comparable conditions; there was no statistical difference in overall efficacy observed between the two sowing methods. We project that strip-sowing could reduce by two thirds the amount of active 1080 applied per hectare in aerial control operations against rabbits, both reducing the non-target poisoning risk and promoting cost savings to farming operations. These results indicate that, similarly to the recently-highlighted benefits of adopting strip-sowing for poison control of introduced brushtail possums (Trichosurus vulpecula) in New Zealand, aerial strip-sowing of toxic bait could also be considered a best practice method for rabbit control in pest control policy.

No MeSH data available.


Related in: MedlinePlus

Location of the semi-arid areas in New Zealand where two methods of aerially-sowing 1080-bait to control rabbits were compared in trials in 2011–2014.In the North Island, 3 trials were conducted in 2013 within Cape Sanctuary near Napier in the Hawkes Bay region (a); in the South Island, 19 trials were conducted between 2011−2014 across a number of properties located in Central Otago and Queenstown Lakes districts (b). Location of trials using broadcast application of bait are shown as black circles, whereas those where strip-sowing was used are shown as grey diamonds.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4920370&req=5

pone.0158078.g001: Location of the semi-arid areas in New Zealand where two methods of aerially-sowing 1080-bait to control rabbits were compared in trials in 2011–2014.In the North Island, 3 trials were conducted in 2013 within Cape Sanctuary near Napier in the Hawkes Bay region (a); in the South Island, 19 trials were conducted between 2011−2014 across a number of properties located in Central Otago and Queenstown Lakes districts (b). Location of trials using broadcast application of bait are shown as black circles, whereas those where strip-sowing was used are shown as grey diamonds.

Mentions: We compared the outcomes of broadcast and strip-sowing treatments applied to twenty-two ~160 ha study blocks by counting rabbits (at night) along transects before and after aerial 1080 baiting, and then comparing the relative reduction in rabbit counts between the two treatments. The study blocks were located within two rabbit-prone regions: Central Otago and Queenstown Lakes districts, South Island (hereafter referred to as Central Otago); and Cape Sanctuary, Coastal Hawkes Bay District, North Island (hereafter referred to as Hawkes Bay), New Zealand (close to the town of Napier; Fig 1). Central Otago is semi-arid (mean annual rainfall 350−650 mm) and is characterized by cold winters (average mid-winter (Jul.) min. to max. = -1.5−8.0°C) and warm summers (average mid-summer (Jan.) min. to max. = 11.0−24.4°C). The region comprises short-tussock grassland interspersed by shrubs and pastureland [8] and supports high rabbit populations that generally exceed a spotlight count index of 40 rabbits per linear km [7, 30, 31]. Hawkes Bay is also relatively dry land (mean annual rainfall 784 mm) and has mild winters (average mid-winter min. to max. = 5.6−14.1°C) and warm summers (average mid-summer min. to max. = 14.6−24.5°C). Our study sites in this region were on agricultural land with surrounding patches of native forest in the Cape Sanctuary wildlife sanctuary [32], habitat that supports medium to high rabbit numbers (i.e. spotlight count indices generally of 10–20 rabbits per linear km [7, 30]).


Refining Operational Practice for Controlling Introduced European Rabbits on Agricultural Lands in New Zealand.

Latham AD, Latham MC, Nugent G, Smith J, Warburton B - PLoS ONE (2016)

Location of the semi-arid areas in New Zealand where two methods of aerially-sowing 1080-bait to control rabbits were compared in trials in 2011–2014.In the North Island, 3 trials were conducted in 2013 within Cape Sanctuary near Napier in the Hawkes Bay region (a); in the South Island, 19 trials were conducted between 2011−2014 across a number of properties located in Central Otago and Queenstown Lakes districts (b). Location of trials using broadcast application of bait are shown as black circles, whereas those where strip-sowing was used are shown as grey diamonds.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920370&req=5

pone.0158078.g001: Location of the semi-arid areas in New Zealand where two methods of aerially-sowing 1080-bait to control rabbits were compared in trials in 2011–2014.In the North Island, 3 trials were conducted in 2013 within Cape Sanctuary near Napier in the Hawkes Bay region (a); in the South Island, 19 trials were conducted between 2011−2014 across a number of properties located in Central Otago and Queenstown Lakes districts (b). Location of trials using broadcast application of bait are shown as black circles, whereas those where strip-sowing was used are shown as grey diamonds.
Mentions: We compared the outcomes of broadcast and strip-sowing treatments applied to twenty-two ~160 ha study blocks by counting rabbits (at night) along transects before and after aerial 1080 baiting, and then comparing the relative reduction in rabbit counts between the two treatments. The study blocks were located within two rabbit-prone regions: Central Otago and Queenstown Lakes districts, South Island (hereafter referred to as Central Otago); and Cape Sanctuary, Coastal Hawkes Bay District, North Island (hereafter referred to as Hawkes Bay), New Zealand (close to the town of Napier; Fig 1). Central Otago is semi-arid (mean annual rainfall 350−650 mm) and is characterized by cold winters (average mid-winter (Jul.) min. to max. = -1.5−8.0°C) and warm summers (average mid-summer (Jan.) min. to max. = 11.0−24.4°C). The region comprises short-tussock grassland interspersed by shrubs and pastureland [8] and supports high rabbit populations that generally exceed a spotlight count index of 40 rabbits per linear km [7, 30, 31]. Hawkes Bay is also relatively dry land (mean annual rainfall 784 mm) and has mild winters (average mid-winter min. to max. = 5.6−14.1°C) and warm summers (average mid-summer min. to max. = 14.6−24.5°C). Our study sites in this region were on agricultural land with surrounding patches of native forest in the Cape Sanctuary wildlife sanctuary [32], habitat that supports medium to high rabbit numbers (i.e. spotlight count indices generally of 10–20 rabbits per linear km [7, 30]).

Bottom Line: In each case, experimental sowing via strip patterns using 10-15 kg of bait per hectare was compared with the current best practice of aerial broadcast sowing at 30-35 kg/ha.We project that strip-sowing could reduce by two thirds the amount of active 1080 applied per hectare in aerial control operations against rabbits, both reducing the non-target poisoning risk and promoting cost savings to farming operations.These results indicate that, similarly to the recently-highlighted benefits of adopting strip-sowing for poison control of introduced brushtail possums (Trichosurus vulpecula) in New Zealand, aerial strip-sowing of toxic bait could also be considered a best practice method for rabbit control in pest control policy.

View Article: PubMed Central - PubMed

Affiliation: Wildlife Ecology & Management, Landcare Research, P.O. Box 69040, Lincoln 7640, New Zealand.

ABSTRACT
European rabbits (Oryctolagus cuniculus) pose a major threat to agricultural production and conservation values in several countries. In New Zealand, population control via poisoning is a frontline method for limiting rabbit damage, with large areas commonly treated using the metabolic toxin sodium fluoroacetate ('1080') delivered in bait via aerial dispersal. However, this method is expensive and the high application rates of the active ingredient cause public antipathy towards it. To guide reductions in cost and toxin usage, we evaluated the economics and efficacy of rabbit control using an experimental approach of sowing 1080-bait in strips instead of the commonly-used broadcast sowing method (i.e. complete coverage). Over a 4-year period we studied aerial delivery of 0.02% 1080 on diced carrot bait over ~3500 ha of rabbit-prone land in the North and South islands. In each case, experimental sowing via strip patterns using 10-15 kg of bait per hectare was compared with the current best practice of aerial broadcast sowing at 30-35 kg/ha. Operational kill rates exceeded 87% in all but one case and averaged 93-94% across a total of 19 treatment replicates under comparable conditions; there was no statistical difference in overall efficacy observed between the two sowing methods. We project that strip-sowing could reduce by two thirds the amount of active 1080 applied per hectare in aerial control operations against rabbits, both reducing the non-target poisoning risk and promoting cost savings to farming operations. These results indicate that, similarly to the recently-highlighted benefits of adopting strip-sowing for poison control of introduced brushtail possums (Trichosurus vulpecula) in New Zealand, aerial strip-sowing of toxic bait could also be considered a best practice method for rabbit control in pest control policy.

No MeSH data available.


Related in: MedlinePlus