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.

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.

scholarly journals The role of New Zealand endemic lizards in Salmonella transmission in the takahē translocation network

2021 ◽  
Author(s):  
◽  
Shanna Rose
Keyword(s):  
New Zealand ◽  
Sympatric Species ◽  
Soil Samples ◽  
Seasonal Patterns ◽  
Salmonella Infection ◽  
Wildlife Species ◽  
The World ◽  
Wildlife Populations ◽  
Significant Mortality

<p>The dynamics of disease in wildlife populations often involve a complex relationship between physiological, environmental and ecological variables. Defining the pattern of pathogen infection between primary hosts, sympatric species and their environments is crucial in the understanding of potential impacts a pathogen may have on its host species. Very little is known about pathogens of native, New Zealand wildlife. Understanding the role pathogens play in structuring communities is crucial in the conservation of threatened New Zealand wildlife species. Salmonella is an important pathogen of reptiles, birds and mammals, and Salmonellosis has caused significant mortality in wildlife around the world. Recently, Salmonella has been isolated from takahē from a private island in the takahē translocation network. Reptiles have been implicated as asymptomatic carriers and transmitters of Salmonella, and lizards from a private (undisclosed) island have been implicated in the transmission of Salmonella to takahē. To investigate the capacity for lizards to act as a Salmonella reservoir in the takahē translocation network, I examined the distribution, abundance and Salmonella prevalence of lizards within takahē territories on the private island and on Maud Island where takahē also reside. Additionally, I investigated the presence of Salmonella in soil and water samples from takahē territories on the private island, Maud Island and at the Burwood Bush takahē rearing facility. Lizard densities on the private island were estimated to be between 466-6020 lizards/ha, and 118-1528 lizards/ha on Maud Island. Salmonella serovars concurrent with those isolated from takahē were isolated from 2% of lizards, 25% of water and 50% of soil samples on the private island, indicating that lizards and the environment play an important role in transmission and maintenance of Salmonella to takahē. Salmonella was not isolated from lizards or environmental samples on Maud Island or at Burwood Bush, indicating prevalence too low to detect in this study or a Salmonella reservoir unique to the private island. Further investigation of Salmonella sources; serovars and seasonal patterns of Salmonella infection is needed to better inform takahē translocation actions on the private island. Additionally, further examination of Salmonella in lizards and the environment is necessary to assess the risk of Salmonella infection to takahē on Maud Island.</p>

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.

scholarly journals The role of New Zealand endemic lizards in Salmonella transmission in the takahē translocation network

2021 ◽  
Author(s):  
◽  
Shanna Rose
Keyword(s):  
New Zealand ◽  
Sympatric Species ◽  
Soil Samples ◽  
Seasonal Patterns ◽  
Salmonella Infection ◽  
Wildlife Species ◽  
The World ◽  
Wildlife Populations ◽  
Significant Mortality

<p>The dynamics of disease in wildlife populations often involve a complex relationship between physiological, environmental and ecological variables. Defining the pattern of pathogen infection between primary hosts, sympatric species and their environments is crucial in the understanding of potential impacts a pathogen may have on its host species. Very little is known about pathogens of native, New Zealand wildlife. Understanding the role pathogens play in structuring communities is crucial in the conservation of threatened New Zealand wildlife species. Salmonella is an important pathogen of reptiles, birds and mammals, and Salmonellosis has caused significant mortality in wildlife around the world. Recently, Salmonella has been isolated from takahē from a private island in the takahē translocation network. Reptiles have been implicated as asymptomatic carriers and transmitters of Salmonella, and lizards from a private (undisclosed) island have been implicated in the transmission of Salmonella to takahē. To investigate the capacity for lizards to act as a Salmonella reservoir in the takahē translocation network, I examined the distribution, abundance and Salmonella prevalence of lizards within takahē territories on the private island and on Maud Island where takahē also reside. Additionally, I investigated the presence of Salmonella in soil and water samples from takahē territories on the private island, Maud Island and at the Burwood Bush takahē rearing facility. Lizard densities on the private island were estimated to be between 466-6020 lizards/ha, and 118-1528 lizards/ha on Maud Island. Salmonella serovars concurrent with those isolated from takahē were isolated from 2% of lizards, 25% of water and 50% of soil samples on the private island, indicating that lizards and the environment play an important role in transmission and maintenance of Salmonella to takahē. Salmonella was not isolated from lizards or environmental samples on Maud Island or at Burwood Bush, indicating prevalence too low to detect in this study or a Salmonella reservoir unique to the private island. Further investigation of Salmonella sources; serovars and seasonal patterns of Salmonella infection is needed to better inform takahē translocation actions on the private island. Additionally, further examination of Salmonella in lizards and the environment is necessary to assess the risk of Salmonella infection to takahē on Maud Island.</p>

scholarly journals Calibration of possum density estimates from raised leghold traps

2001 ◽  
Vol 54 ◽  
pp. 71-75
Author(s):  
M. Thomas ◽  
J.A. Brown
Keyword(s):  
Field Trials ◽  
Brushtail Possum ◽  
Population Abundance ◽  
Trichosurus Vulpecula ◽  
Trap Catch ◽  
Density Estimates ◽  
Catch Rates

We undertook field trials to compare differences between ground and raisedset leghold traps to measure population abundance of the brushtail possum (Trichosurus vulpecula) We discuss the observed differences in trap catch rates and the use and potential misuse of a calibration index to correct the raisedset estimates so they can be compared with the groundset estimates

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.

scholarly journals Mycobacterium bovis (bovine tuberculosis) infection in North American wildlife: current status and opportunities for mitigation of risks of further infection in wildlife populations

2013 ◽  
Vol 141 (7) ◽  
pp. 1357-1370 ◽  
Author(s):  
R. S. MILLER ◽  
S. J. SWEENEY
Keyword(s):  
Risk Factors ◽  
North America ◽  
Mycobacterium Bovis ◽  
North American ◽  
Bovine Tuberculosis ◽  
Bacterial Pathogen ◽  
Current Status ◽  
Wildlife Species ◽  
The Usa ◽  
Wildlife Populations

SUMMARYMycobacterium bovis (M. bovis), the causative agent of bovine tuberculosis, has been identified in nine geographically distinct wildlife populations in North America and Hawaii and is endemic in at least three populations, including members of the Bovidae, Cervidae, and Suidae families. The emergence of M. bovis in North American wildlife poses a serious and growing risk for livestock and human health and for the recreational hunting industry. Experience in many countries, including the USA and Canada, has shown that while M. bovis can be controlled when restricted to livestock species, it is almost impossible to eradicate once it has spread into ecosystems with free-ranging maintenance hosts. Therefore, preventing transmission of M. bovis to wildlife may be the most effective way to mitigate economic and health costs of this bacterial pathogen. Here we review the status of M. bovis infection in wildlife of North America and identify risks for its establishment in uninfected North American wildlife populations where eradication or control would be difficult and costly. We identified four common risk factors associated with establishment of M. bovis in uninfected wildlife populations in North America, (1) commingling of infected cattle with susceptible wildlife, (2) supplemental feeding of wildlife, (3) inadequate surveillance of at-risk wildlife, and (4) unrecognized emergence of alternate wildlife species as successful maintenance hosts. We then propose the use of integrated and adaptive disease management to mitigate these risk factors to prevent establishment of M. bovis in susceptible North American wildlife species.

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