Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: The efficacy of rabbit Oryctolagus cuniculus exclusion fence designs for threatened species protection at the Arid Recovery Conservation Project Reserve, South Australia

Published source details

Moseby K.E. & Read J.L. (2006) The efficacy of feral cat, fox and rabbit exclusion fence designs for threatened species protection. Biological Conservation, 127, 429-437

Summary

Many government and private conservation organizations on mainland Australia rely on exclusion fences for the protection and reintroduction of threatened species. Competition from introduced European rabbit Oryctolagus cuniculus populations with native species such as the eastern barred bandicoot Perameles gunnii, mala Lagorchestes hirsutus, burrowing bettong Bettongia lesueur, greater bilby Macrotis lagotis and western barred bandicoot Perameles bougainville can be a driver of population declines. Fence testing helps to maximize the effectiveness of fence exclosures, however, most types of exclusion fence have not been trialed in Australia. Experimental pen trials were conducted to test the efficacy and cost effectiveness of rabbit exclusion fences at the Arid Recovery conservation project reserve in South Australia.

Study site: The Arid Recovery conservation project has removed European rabbits Oryctolagus cuniculus, feral cats Felis catus (see: www.conservationevidence.com/ViewSummary.aspx?ID=10419) and red foxes Vulpes vulpes (www.conservationevidence.com/ViewSummary.aspx?ID=10420) from a 60 km² fenced reserve. Rabbit densities around the reserve can exceed 200 individuals per km². The habitat is lowland shrubland/chenopod scrub dominated by saltbush Atriplex spp. and bluebush Maireana spp. The rabbit fence trial was undertaken from March 1998 to August 1999.
 
Fence design: An L-shaped pen of 20 x 20 m was constructed incorporating one external corner. Pine posts 1.8 m tall (from ground level) were installed at 10 m intervals and on each corner of the pen. Wire mesh netting 40 mm (mesh diameter) x 1.4 mm (wire thickness) x 900 mm (high) was clipped from ground level to 90 cm height using ring fasteners. A net (40 x 1.4 x 300 mm) foot apron was clipped to the ground level selvage wire, stretched into the exclosure to 30 cm and buried.

Rabbit observations: Two juvenile rabbits were caught by hand and placed in the enclosure. Video observations were made as they tried to breach the wire mesh fencing.

Manual testing: The effectiveness of three different mesh sizes (30, 37 and 40 mm diameter) was tested by trying to pull 21 dead juvenile rabbits, weighing from 148 to 918 g, through the netting.

Rabbit observations: The 40 mm mesh diameter netting was not adequate to exclude juvenile rabbits. The two placed within the exclosure escaped within 30 seconds of release by squeezing through the netting. One of these rabbits repeatedly jumped in and out of the pen through the netting.

At least 12 other rabbits were able to gain access to the exclosure by squeezing through the netting. Once additional 30 mm diameter netting was added to the fence, no rabbits breached the netting over the five year study period.

Manual testing: Of the 21 juvenile rabbits used, only the ones weighing up to 495g could be pulled through the 40 mm diameter netting. Only one small juvenile rabbit was successfully pulled through the 30 mm diameter netting.

Fence features: The 30 cm foot apron was effective at preventing rabbits from digging at the base of the fence. However, wider netting or heavy rubber matting may be necessary to stop rabbit incursions in areas of softer substrate such as sand dunes or watercourses.

Netting cost: The 30 cm mesh diameter hexagonal netting was very expensive and accounted for 57% of the fence cost. Fence contruction expense could be reduced by adding netting to existing stock fences.

Conclusions: Trials at the Arid Recovery conservation project reserve suggest that a combination of 30 mm mesh diameter wire netting and 30 cm horizontal foot aprons are necessary when trying to prevent rabbit incursions into a conservation area. Where netting joints do not overlap, it is recommended that clips be added, spaced at a maximum of 10 cm to prevent rabbits from squeezing through gaps.


Note: If using or referring to this published study, please read and quote the original paper.