The effect of manipulating population density on the probability of den-sharing among common brushtail possums, and the implications for transmission of bovine tuberculosis

1998 ◽  
Vol 25 (4) ◽  
pp. 383 ◽  
Author(s):  
P. Caley ◽  
N. J. Spencer ◽  
R. A. Cole ◽  
M. G. Efford
Keyword(s):  
New Zealand ◽  
Population Density ◽  
Bovine Tuberculosis ◽  
Brushtail Possum ◽  
Contact Rate ◽  
Animal Disease ◽  
Per Capita ◽  
A Site ◽  
And Control ◽  
The Relationship

Common brushtail possums (Trichosurus vulpecula) act as a reservoir of bovine tuberculosis (Mycobacterium bovis) in New Zealand and the simultaneous sharing of dens may result in the transmission of Tb between possums. The effect of manipulating population density on the per capita probability of simultaneous den-sharing among possums was investigated at a site near Dunedin, New Zealand. Den characteristics that could affect the probability of simultaneous sharing were also investigated, though none were found to be significant. The daily probability of a possum sharing a den was estimated to be 0.07 for possums denning within uncontrolled areas of the study area. Den-sharing was most common between female pairs, though sharing was also recorded between male–female and male–male pairs. The highest number of possums recorded sharing a single den was four. Reducing population density significantly lowered the probability of possums simultaneously sharing dens within the study area, with greater than 60% reductions estimated to eliminate simultaneous den-sharing altogether. The relationship between the contact rate arising from den-sharing and population density was convex-down, rather than convex-up, as often hypothesised for animal–animal disease contact processes. The implications of simultaneous den-sharing for the transmission and control of bovine tuberculosis in brushtail possum populations are discussed.

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.

Diminishing returns in bovine tuberculosis control

2013 ◽  
Vol 141 (7) ◽  
pp. 1382-1389 ◽  
Author(s):  
J. HONE
Keyword(s):  
New Zealand ◽  
Bovine Tuberculosis ◽  
Linear Models ◽  
Brushtail Possum ◽  
Regression Analyses ◽  
Tuberculosis Control ◽  
Tb Control ◽  
Diminishing Returns ◽  
Best Fitting ◽  
Strength Of Association

SUMMARYMycobacterium bovis causes bovine tuberculosis (bTB) in many mammals including cattle, deer and brushtail possum. The aim of this study was to estimate the strength of association, using model selection (AICc) regression analyses, between the proportion of cattle and farmed deer herds with bTB in New Zealand and annual costs of TB control, namely disease control in livestock, in wildlife or in a combination of the two. There was more support for curved (concave up) than linear models which related the proportion of cattle and farmed deer herds with bTB to the annual control costs. The curved, concave-up, best-fitting relationships showed diminishing returns with no positive asymptote and implied TB eradication is feasible in New Zealand.

Dietary changes in response to population reduction in the possum Trichosurus vulpecula in New Zealand

2013 ◽  
Vol 40 (7) ◽  
pp. 561 ◽  
Author(s):  
Peter J. Sweetapple ◽  
Wendy A. Ruscoe ◽  
Graham Nugent
Keyword(s):  
New Zealand ◽  
Pest Control ◽  
Population Control ◽  
Stomach Contents ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Dietary Changes ◽  
Before And After ◽  
Per Capita ◽  
Indigenous Forest

Context Efforts to protect or restore degraded plant communities by population control of invasive herbivores frequently fail to achieve their goals. Aims We seek to quantify changes in diet of an introduced herbivore, the brushtail possum (Trichosurus vulpecula), following population control, and determine how these may contribute to variable responses in plant condition. Methods Stomach contents of possums from five areas of indigenous forest in northern New Zealand were analysed to measure diet before and after the application of possum control. Key results The contribution of fruit, and foliage of some early successional forest species, to total possum diet increased up to 27-fold following possum population control. This was accompanied by declines in consumption of the main pre-control possum foods (foliage from common canopy trees). Dietary changes were a combination of an immediate response to control (1 year) and a strengthening of these initial changes with increasing time since control. Conclusions Possums in the study areas changed diet following population control, from a diet dominated by foliage of common canopy tree species to one dominated by fruits, and foliage of uncommon early successional plants. Pest control instantaneously increased the per capita availability of all foods, and probably permitted absolute increases in some foods through plant recovery, enabling possums to substitute scarce, high-preference foods for abundant but less preferred canopy foliage. Implications Following control of a pest herbivore, dietary changes reduce benefits for the most vulnerable preferred plant foods, but enhance benefits for less favoured plants. Intense pest control can permit some recovery of highly preferred foods, despite increased per capita consumption of these foods by survivors of control.

scholarly journals POTRET IPM DI PROPINSI JAWA TIMUR TAHUN 2000-2012

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Prayudi Setiawan Prabowo
Keyword(s):  
Population Density ◽  
Capita Income ◽  
Quantitative Research ◽  
Population Control ◽  
Per Capita Income ◽  
Education And Health ◽  
Per Capita ◽  
The Government ◽  
The Relationship

This study aims to find the relationship between compliance with HDI in East Java. With case study on Surabaya, Sidoarjo and Gresik. Where is expected to recover low HDI East Java in Java Island that year. The method to be used in this research is descriptive Quantitative research method. The first result, success in controlling the population both from the side of birth control and in-migration, will enable the achievement of a relatively low population density. As the population density diminishes, the education budget and health budget issued by the government will have a more significant impact on improving education and public health. This will ultimately increase HDI, as education and health levels are a dimension in HDI measurement. Second, population control will increase per capita income. Per capita income (GRDP per capita) of GRDP is divided by the total population. With fewer populations, GDP per capita will tend to be higher. High per capita income will increase HDI growth.

scholarly journals A comparison of wildlife control and cattle vaccination as methods for the control of bovine tuberculosis

1999 ◽  
Vol 122 (3) ◽  
pp. 505-519 ◽  
Author(s):  
R. R. KAO ◽  
M. G. ROBERTS
Keyword(s):  
New Zealand ◽  
Great Britain ◽  
Control Strategy ◽  
Bovine Tuberculosis ◽  
Cost Effective ◽  
Control Area ◽  
Brushtail Possum ◽  
Source Of Infection ◽  
Wildlife Control ◽  
The Cost

The Australian brushtail possum is the major source of infection for new cases of bovine tuberculosis in cattle in New Zealand. Using hypothetical values for the cost of putative cattle and possum Tb vaccines, the relative efforts required to eradicate Tb in cattle using possum culling, possum vaccination or cattle vaccination are compared. For realistic assumed costs for 1080 poison bait, possum culling is found to be a cost-effective strategy compared to cattle vaccination if the required control area is below 13 ha per cattle herd, while possum vaccination is cost-effective for control areas of less than 3 ha per herd. Examination of other considerations such as the possible roles of possum migration and heterogeneities in possum population density suggest that each control strategy may be superior under different field conditions. Finally, the roles of the possum in New Zealand, and the Eurasian badger in Great Britain and Ireland in the transmission of bovine tuberculosis to cattle are compared.

Population Ex(im)plosion?

1972 ◽  
Vol 30 (1) ◽  
pp. 3-6
Author(s):  
Fred Heilizer
Keyword(s):  
Population Density ◽  
Capita Income ◽  
Positive Relationship ◽  
Negative Relationship ◽  
Per Capita Income ◽  
Population Explosion ◽  
Per Capita ◽  
The Relationship

The relationship between population density and per capita income was investigated for 117 nations with a population of more than one million persons. H1, the population explosion hypothesis, asserts that there is a negative relationship. H2, the population implosion hypothesis, asserts that there is a positive relationship. The data favor H2 rather than H1.

Urban structures, population density and municipal expenditures: An empirical study in the Czech Republic

Urban Studies ◽  
2019 ◽  
Vol 56 (16) ◽  
pp. 3450-3465 ◽  
Author(s):  
Tomáš Hudeček ◽  
Pavel Hnilička ◽  
Martin Dlouhý ◽  
Lucie Leňo Cutáková ◽  
Michal Leňo
Keyword(s):  
Population Density ◽  
Public Space ◽  
Urban Structure ◽  
Urban Spatial Structure ◽  
The Czech Republic ◽  
Urban Structures ◽  
Per Capita ◽  
The Relationship ◽  
Lower Size ◽  
Municipal Expenditures

The objective of this study is to investigate the relationship between the type of urban spatial structure, population density and the selected types of capital and current municipal expenditures. Seven types of urban spatial structures at the level of city blocks are defined. Different types of municipal expenditure (urban green, pavement, roadway and public lighting) are estimated by the data from 22 Czech cities and six city districts. The capital and current municipal expenditures are calculated for each urban structure per hectare and per capita. The most expensive urban structure per hectare is the urban structure of estates and high rises, which is caused by the large proportion of public space. On the other hand, single detached houses are the least costly. If the population density is taken into account and municipal expenditures are calculated per capita, the least costly urban structure is the urban block structure followed by the organic urban structure (historical centre), which is given by high population density and lower size of public space. The urban structure of single detached houses is the most costly urban structure per capita.

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