Restricting the movements of brushtail possums (Trichosurus vulpecula) on farmland with electric fencing

1992 ◽  
Vol 19 (1) ◽  
pp. 47 ◽  
Author(s):  
PE Cown ◽  
DS Rhodes
Keyword(s):  
New Zealand ◽  
Bovine Tuberculosis ◽  
Trichosurus Vulpecula ◽  
Electric Fence ◽  
Electric Fencing

A trial was conducted to test whether an electric fence would limit local movements of brushtail possums (Trichosurus vulpecula) on farmland in the central North I. of New Zealand. If effective, such a system could be used to reduce possum and cattle interactions and the spread of bovine tuberculosis. A 3-km-long, 9-strand electric fence was erected from ridge to ridge across a valley catchment of about 160 ha. Possums were live-trapped and released at bush patches within the study area and in open areas immediately adjacent to the electric fence. Only about 30% of possums caught at local bush patches were ever retrapped at the fence, and most were caught only once at the fence. About a third of possums caught at the fence were trapped at least once on both sides of the fence. The electric fence reduced possum movements through the fenced area by about 60-80%. Most possums trapped at the fence had come from bush patches within 200 m of the fence. When the fence was switched off, possum captures on the outside increased rapidly. The effectiveness of the fence was reduced because of frequent voltage reduction by earthing from a wide variety of causes, and because possums learned to move around the ends of the fence and the fences along the farm roads. Improvements to fence design are discussed.

Distribution, Prevalence, and Epidemiology of Bovine Tuberculosis in Brushtail Possums, Trichosurus-Vulpecula, in the Hohonu Range, New-Zealand

1988 ◽  
Vol 15 (6) ◽  
pp. 651 ◽  
Author(s):  
JD Coleman
Keyword(s):  
Body Weight ◽  
Lymph Node ◽  
New Zealand ◽  
Disease Transmission ◽  
Bovine Tuberculosis ◽  
Infected Animal ◽  
Disease Prevalence ◽  
Trichosurus Vulpecula ◽  
Wide Range ◽  
Autumn And Winter

Over a 12-month period, 1467 brushtail possums were trapped and then killed or were poisoned along sampling lines on pasture-forest margins and in nearby forest. An additional 334 possums were shot on adjacent farm land. All possums were necropsied, and 141 had macroscopic lesions typical of bovine tuberculosis. Infected possums occurred most commonly in small foci of 2-5 individuals along pasture-forest margins; the furthest from pasture that an infected animal was taken was 4050 m. Lesions occurred in possums of all ages in both sexes, but disease prevalence was highest in immature males and during autumn and winter. Infected possums bred as successfully as non-infected individuals, but were of lighter body weight. Macroscopic lesions occurred in a wide range of visceral and lymph node sites. Lesions were most common in the lungs and axillary nodes, and occasionally formed open sinuses from which infected possums could shed M. bovis readily, and thus were likely to be highly infective. Evidence suggested that disease transmission occurs most frequently on pasture-forest margins, where possum numbers are greatest and possum and cattle mix most freely.

Impact of bovine tuberculosis on a population of brushtail possums (Trichosurus vulpecula Kerr) in the Orongorongo Valley, New Zealand

2004 ◽  
Vol 31 (4) ◽  
pp. 389 ◽  
Author(s):  
A. Arthur ◽  
D. Ramsey ◽  
M. Efford
Keyword(s):  
Overall Survival ◽  
New Zealand ◽  
Population Density ◽  
Bovine Tuberculosis ◽  
Local Population ◽  
Trichosurus Vulpecula ◽  
Considerable Uncertainty ◽  
Highly Sensitive ◽  
Competing Models ◽  
The Impact

Brushtail possums are the main wildlife vectors of bovine tuberculosis (Tb) in New Zealand. Possum–Tb models form the basis of possum control aimed at eradicating the disease, and yet competing models show different behaviour, and are highly sensitive to parameters about which there is considerable uncertainty. One area of great uncertainty is the impact of the disease on possum populations. We investigated the impact of Tb on a local population of brushtail possums in the Orongorongo Valley, Wellington. Bovine Tb was first detected in 1997 at one site within an intensively studied population, but has not been detected in another intensively studied population 3 km away since the early 1980s. Using a Before-After-Control-Impact (BACI) analysis, detection of Tb coincided with a 42% (95% CI = 23–56%) reduction in the odds of apparent yearly survival of a possum >17 months of age, i.e. a decrease in yearly survival from 0.85 to 0.77 in 'good' years, and a decrease from 0.71 to 0.60 in 'bad' years. This suggests that Tb had a significant impact on overall survival. However, there was no impact on local population density in September each year due to compensatory recruitment.

scholarly journals Geographic distribution of restriction types ofMycobacterium bovisisolates from brush-tailed possums (Trichosurus vulpecula) in New Zealand

1986 ◽  
Vol 96 (3) ◽  
pp. 431-438 ◽  
Author(s):  
D. M. Collins ◽  
G. W. De Lisle ◽  
D. M. Gabric
Keyword(s):  
New Zealand ◽  
High Resolution ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Restriction Enzymes ◽  
Restriction Endonuclease Analysis ◽  
Trichosurus Vulpecula ◽  
Typing System ◽  
Dna Restriction ◽  
Endonuclease Analysis

SUMMARYDNA restriction endonuclease analysis was used for intra-specific typing ofMycobacterium bovisisolates from 83 brush-tailed possums (Trichosurus vulpecula) obtained between 1982 and 1984 from the three major regions in New Zealand with endemic bovine tuberculosis. All the isolates were found to be genetically very similar. Differentiation of the isolates into 33 restriction types was achieved by using high-resolution electrophoresis and the combined results from separate digestions with the restriction enzymesBstEII,PvuII andBclI. The typing system was entirely reproducible. Isolates of the same type were usually found in adjacent localities and were always limited to one of the three major regions. In some cases, isolates of the same type were found in both 1982 and 1984. The phenotypic significance of the small genetic differences identified between different isolates is unknown. The typing system will be useful for monitoring the transmission ofM. bovisto other species and the future spread of differentM. bovistypes through possum populations.

A new trap-catch index of patchiness in animal distribution

2004 ◽  
Vol 31 (4) ◽  
pp. 433 ◽  
Author(s):  
J. A. Brown ◽  
R. J. McAuliffe ◽  
G. J. Hickling
Keyword(s):  
New Zealand ◽  
Species Distribution ◽  
Bovine Tuberculosis ◽  
Trichosurus Vulpecula ◽  
Trap Catch ◽  
Animal Distribution ◽  
Wildlife Species ◽  
Wildlife Populations ◽  
Catch Rates ◽  
Index Of Abundance

Researchers and managers commonly use catch rates on trap-transects as an index of abundance for trappable wildlife species. We describe a method whereby the data collected from such surveys can be further analysed to obtain information on the patchiness of the trapped species' distribution on those transects. For certain applications, such as the management of wildlife disease, the index is likely to have significant advantages over traditional indices of spatial aggregation. One such situation is the management of brushtail possums (Trichosurus vulpecula) in New Zealand to inhibit the spread of bovine tuberculosis within their populations. Trap-catch data from a possum survey are used to illustrate the proposed method, and the potential for application of such monitoring to wildlife populations is discussed.

Den Sites of Possums, Trichosurus-Vulpecula, and Frequency of Use in Mixed Hardwood Forest in Westland, New-Zealand

1987 ◽  
Vol 14 (3) ◽  
pp. 285 ◽  
Author(s):  
WQ Green ◽  
JD Coleman
Keyword(s):  
New Zealand ◽  
Bovine Tuberculosis ◽  
Ground Level ◽  
Root Systems ◽  
Hardwood Forest ◽  
Trichosurus Vulpecula ◽  
Frequency Of Use ◽  
Below Ground ◽  
Males And Females

Forty-seven common brushtail possums, Trichosurus vulpecula, were radiotracked to 282 dens on 546 occasions. Just over half of all dens were in living trees; the remainder were evenly distributed between dead standing stems (including short stumps) and logs, with a few (3%) in banks and rock fissures. Of all the den entrances, 73% were at, or below, ground level amongst root systems or in logs. Although dead standing stems (over 25 cm d.b.h.) made up only 4% of standing stems in forest below 500 m altitude, they contained 41% of the dens. Each possum probably used between 10 and 15 dens each year. There were no differences in den choice and frequency of use between mature males and females. Den choice by matures and immatures was similar, but mature possums used dens in 'dead' sites more than did immatures. The implications of dens in the transmission of bovine tuberculosis are discussed.

Electric Fences and Poison Buffers as Barriers to Movements and Dispersal of Brushtail Possums (Trichosurus Vulpecula) on Farmland.

1993 ◽  
Vol 20 (5) ◽  
pp. 671 ◽  
Author(s):  
PE Cowan ◽  
DS Rhodes
Keyword(s):  
Bovine Tuberculosis ◽  
Average Distance ◽  
Buffer Zone ◽  
Control Site ◽  
Trichosurus Vulpecula ◽  
Buffer Zones ◽  
North West ◽  
North East ◽  
Live Trapping ◽  
Electric Fence

Limitation of the spread of bovine tuberculosis by brushtail possums (Trichosurus vulpecula) in New Zealand involves creating buffer zones 3-5km wide around areas where the disease is endemic in possum populations; low possum density is established by aerial and ground poisoning and maintained by repeated control. The effectiveness of a buffer zone was examined using live-trapping and radiotracking to study movements and dispersal of juvenile and adult possums in comparison with a nearby, undisturbed (control) site. At a third site, the effect of a 3-km long, 9-strand electric fence, erected from ridge to ridge across a valley catchment, for reducing possum dispersal was measured, as an alternative to a buffer zone. Adult possums were highly sedentary; only one permanent shift of more than 0.5km was detected during repeated live-trapping and radio-tracking, and most consecutive live captures were in traps less than 200m apart. None of the radio-tagged adults adjacent to the poison buffer zones moved permanently into the low-density areas. By contrast, about 20% of radio-tagged juveniles dispersed more than 0.5km, moving up to 11.6km from their natal areas, most in a generally west-north-west to east-north-east direction. About equal numbers dispersed upstream, downstream, or in other directions. Significantly more males dispersed than females, but their dispersal distances were similar. Some dispersing possums moved more than 2km overnight, and females, particularly, often made several moves before settling. Most juveniles dispersed before they were one year old, mainly in the three months immediately preceding the peak of births in autumn. Neither the poison buffer zone nor the electric fence appeared to influence the proportion of juveniles that dispersed more than 0.5km, or the average distance dispersed. The implications of these findings in preventing the spread of bovine tuberculosis are discussed.

A simulation model for the spread of bovine tuberculosis within New Zealand cattle herds

1997 ◽  
Vol 32 (1-2) ◽  
pp. 57-75 ◽  
Author(s):  
N.D. Barlow ◽  
J.M. Kean ◽  
G. Hickling ◽  
P.G. Livingstone ◽  
A.B. Robson
Keyword(s):  
New Zealand ◽  
Simulation Model ◽  
Bovine Tuberculosis ◽  
Cattle Herds
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