Analysis of the impact of stoats, Mustela erminea, on northern brown kiwi, Apteryx mantelli, in New Zealand

1999 ◽  
Vol 26 (2) ◽  
pp. 227 ◽  
Author(s):  
B. Basse ◽  
J. A. McLennan ◽  
G. C. Wake
Keyword(s):  
New Zealand ◽  
Population Analysis ◽  
Recruitment Rate ◽  
Predator Control ◽  
Mustela Erminea ◽  
Small Areas ◽  
Structured Population ◽  
A Value ◽  
Age Structured ◽  
The Impact

An age-structured population analysis is used to determine recruitment levels and a condition for survival which can assist management decisions and hence improve the viability of populations of northern brown kiwi, Apteryx mantelli, in forests on the New Zealand mainland. Currently, in the absence of predator control, recruitment rates are less than 5% due to high levels of stoat, Mustela erminea, predation on juvenile kiwi. Predation levels on adult kiwi are very low. The analysis predicts that a recruitment rate of 19% is required to maintain population stability. To achieve this target, stoat populations have to be reduced by about 80% in some years, and maintained at a critical residual density estimated to be a value less than two animals per square kilometre for up to nine months until immature kiwi reach a safe size of about 1200 g (50% of their adult weight). Recent predator-control initiatives indicate that stoat numbers can be reduced and maintained at low levels in relatively small areas of mainland forest (up to 1000 ha). New techniques are needed to protect kiwi over larger areas.

Survival of femur fractures in wild stoats (Mustela erminea)

2021 ◽  
Vol 30 (4) ◽  
pp. 461-466
Author(s):  
CM King
Keyword(s):  
New Zealand ◽  
Femoral Shaft ◽  
Active Movement ◽  
Predator Control ◽  
Conservation Areas ◽  
Mustela Erminea ◽  
Offshore Island ◽  
Broken Bones ◽  
Femur Fractures

Stoats (Mustela erminea) are active hunters and, therefore, one might predict that any broken bones or other injuries impeding active movement would incur a serious risk of starvation. Dead stoats (n = 560) were collected from trappers operating predator control lines in three conservation areas of New Zealand from 1972–1978. Femurs were cleaned and examined for healed injuries and deformities. Five femurs from four stoats (one with both femurs injured) showed traumatic distortions following healing of complete breaks incurred during life. A further case recorded during post-eradication monitoring in 2010 on Rangitoto, an offshore island, is added. These data provide evidence that wild stoats have a remarkable capacity to tolerate catastrophic femur fractures. They can survive long enough, despite the implied limitation to their energetic hunting style, to permit full healing even though the result is a gross distortion of the femoral shaft.

Effects of predation and rabbit haemorrhagic disease on population dynamics of rabbits (Oryctolagus cuniculus) in North Canterbury, New Zealand

2002 ◽  
Vol 29 (6) ◽  
pp. 627 ◽  
Author(s):  
Ben Reddiex ◽  
Graham J. Hickling ◽  
Grant L. Norbury ◽  
Chris M. Frampton
Keyword(s):  
Population Dynamics ◽  
New Zealand ◽  
Breeding Season ◽  
Predator Control ◽  
Zealand Rabbit ◽  
Rabbit Haemorrhagic Disease ◽  
Low Levels ◽  
Haemorrhagic Disease ◽  
The Impact ◽  
Very High

The impact of predation and rabbit haemorrhagic disease (RHD) on population dynamics of rabbits, and the survival of juvenile rabbits, was investigated between July 1999 and March 2000 in North Canterbury, New Zealand. Rabbit abundance and pre- and post-emergent rabbit mortality were monitored on four sites, two of which were subject to predator control. RHD spread naturally through all sites from late November to early December. Rabbit densities declined on all sites, but after the RHD epidemic, declines were significantly greater where populations of predators had not been controlled. Survival of rabbit nestlings was lower where predators were not controlled. All post-emergent radio-collared rabbits died at sites where predators were not controlled, whereas 18% of those collared at sites where predators were controlled survived to maturity. In contrast to the results from previous studies, rabbits born at the start of the breeding season had very high rates of post-emergent mortality, as they appeared to be susceptible to the RHD virus later in the breeding season. The age at which juvenile rabbits become susceptible to RHD, the timing of RHD epidemics, and the abundance of predators are likely to be important in determining survival of juvenile rabbits. This study demonstrates that predation can reduce rabbit populations to low levels, but only in combination with other factors, in this case RHD.

STRUCTURED INFLUENZA MODEL FOR META-POPULATION

2009 ◽  
Vol 02 (04) ◽  
pp. 525-541 ◽  
Author(s):  
MARIJA ŽIVKOVIĆ GOJOVIĆ ◽  
DONG LIANG ◽  
JIANHONG WU
Keyword(s):  
Control Strategies ◽  
Influenza Pandemic ◽  
Influenza Infection ◽  
Control Measures ◽  
Disease Spread ◽  
Behavior Changes ◽  
Spatial Spread ◽  
Structured Population ◽  
Age Structured ◽  
The Impact

We present a mathematical model parameterized to simulate the 1918 pandemic and modified to account for today's achievements in medical care and technology. Our goal is to use the model with carefully selected parameters to analyze and simulate different scenarios in a changing environment including behavior changes and reduction of mobility as the disease progresses. The model is structured by the disease age, representing the time elapsed since the exposure to influenza infection, and most of the parameters used in this study are thus disease-age dependent. We also consider the case where an influenza pandemic affects two distinct regions, connected only through controlled mobility. We evaluate the influence of different control measures on temporal patterns of disease dynamics and consider the impact of the movement of disease age structured population on spatial spread. A special example is examined that considers different scenarios of disease spread between Canada and USA when different border control strategies are implemented.

Evaluation of a management decision rule for a New Zealand rock lobster substock

1997 ◽  
Vol 48 (8) ◽  
pp. 1093 ◽  
Author(s):  
Paul J. Starr ◽  
Paul A. Breen ◽  
Ray H. Hilborn ◽  
Terese H. Kendrick
Keyword(s):  
New Zealand ◽  
Decision Rule ◽  
Maximum Sustainable Yield ◽  
Assessment Model ◽  
Management Decision ◽  
Catch Per Unit Effort ◽  
Rock Lobster ◽  
Management Actions ◽  
Age Structured ◽  
The Impact

The performance of a proposed management ‘decision rule’–an algorithm that specifies management actions when specified criteria are met–was evaluated by exploring the impact of different choices for three decision-rule parameters on the ability of the rule to achieve management objectives. To do this, forward simulations from an age-structured assessment model for the substock of red rock lobster (Jasus edwardsii) off southern New Zealand were used. The size of this substock is currently estimated to be about one-third of BMSY (the level of vulnerable biomass that would produce maximum sustainable yield), and the management goal is to rebuild it to BMSY. A target rebuilding trajectory to BMSY was generated by allowing the model population to rebuild under the current catch regime with constant recruitment. The decision rule is based on comparison of observed catch per unit effort (CPUE) to predicted CPUE. Process and observation errors, each with a coefficient of variation of 20%, were introduced, and five values were used for each of the three parameters of the rule. The decision rule was effective in removing all instances of failure to rebuild and all excessively slow rebuilding trajectories. The decision rule was also applied to an arbitrarily depressed starting substock size, and the conclusions were the same.

Influence of social networks on business processes’ development

2020 ◽  
Vol 19 (12) ◽  
pp. 2225-2252
Author(s):  
E.V. Popov ◽  
V.L. Simonova ◽  
O.V. Komarova ◽  
S.S. Kaigorodova
Keyword(s):  
Social Networks ◽  
Social Media ◽  
Business Models ◽  
Business Processes ◽  
Digital Economy ◽  
Theoretical Understanding ◽  
Sales Channels ◽  
A Value ◽  
The Impact

Subject. The emergence of new ways of interaction between sellers and buyers, the formation of new sales channels and product promotion based on the use of digital economy tools is at the heart of improving the business processes. Social networks became a tool for development; their rapid growth necessitates theoretical understanding and identification of potential application in enterprise's business process digitalization. Objectives. We explore the role of social media in the digitalization of business processes, systematize the impact of social networks on business processes of enterprises in the digital economy. Methods. The theoretical and methodological analysis of social networks as a tool for digitalization of company's business processes rests on the content analysis of domestic and foreign scientific studies, comparison, generalization and systematization. Results. We highlight the key effects of the impact of social networks on the business processes of the company; show that the digitalization of business processes should be considered in the context of a value-based approach, aimed at creating a value through the algorithmization of company operations. We determine that social networks are one of the most important tools for digitalization of company's business processes, as they have a high organizational and management potential. We also systematize the effects of social media on company's business processes. Conclusions. We present theoretical provisions of the impact of social networks on business processes of enterprises, which will enable to model and organize ideas about the development of digital ecosystems and the formation of business models.

scholarly journals Model-based evaluation of school- and non-school-related measures to control the COVID-19 pandemic

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ganna Rozhnova ◽  
Christiaan H. van Dorp ◽  
Patricia Bruijning-Verhagen ◽  
Martin C. J. Bootsma ◽  
Janneke H. H. M. van de Wijgert ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Additional Benefit ◽  
Transmission Model ◽  
Time Points ◽  
School Based ◽  
Admission Data ◽  
Age Structured ◽  
The Impact ◽  
Pandemic Wave

AbstractThe role of school-based contacts in the epidemiology of SARS-CoV-2 is incompletely understood. We use an age-structured transmission model fitted to age-specific seroprevalence and hospital admission data to assess the effects of school-based measures at different time points during the COVID-19 pandemic in the Netherlands. Our analyses suggest that the impact of measures reducing school-based contacts depends on the remaining opportunities to reduce non-school-based contacts. If opportunities to reduce the effective reproduction number (Re) with non-school-based measures are exhausted or undesired and Re is still close to 1, the additional benefit of school-based measures may be considerable, particularly among older school children. As two examples, we demonstrate that keeping schools closed after the summer holidays in 2020, in the absence of other measures, would not have prevented the second pandemic wave in autumn 2020 but closing schools in November 2020 could have reduced Re below 1, with unchanged non-school-based contacts.

scholarly journals Salt Intake in Nigeria: a nationwide population survey

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A.N Odili ◽  
B.S Chori ◽  
B Danladi ◽  
P.C Nwakile ◽  
J.O Ogedengbe ◽  
...  
Keyword(s):  
Salt Intake ◽  
Sodium Intake ◽  
Population Analysis ◽  
Cost Effective ◽  
Rural Site ◽  
Urban Site ◽  
Funding Source ◽  
Salt Reduction ◽  
High Salt Intake ◽  
The Impact

Abstract Background Population wide salt reduction programmes are cost effective strategies for control of cardiovascular diseases (CVDs). Obtaining a nationwide salt consumption data in a multi-cultural setting as Nigeria's is key for proper implementation and monitoring of such strategy. Methods We measured sodium in 24-hour urine of free-living adult Nigerians selected from an urban and a rural site each from the 6 geopolitical zones of Nigeria to evaluate patterns of salt intake and its associations with blood pressures (BP). Results Across the 12 sites, sodium intake ranged from 97.9 in the rural South-South to 210 mmol/day in the urban site of the same zone. Overall, the median (IQR) daily sodium intake was 143.5 (97.8) mmol; with higher (p=0.0028) levels among the urban 149.7 (113.8) compared to the rural 133.1 (105.2) dwellers. Overall, 20% of the subjects consumed less than the recommended 2g (86mmol) of sodium daily. After adjustment for age, sex and BMI; sodium intake and BP (systolic and diastolic) were positively associated in 8 out of the 12 sites; significantly so in 2 (p<0.05) for systolic. Within population analysis; which included 973 individuals, increasing sodium intake tended (not significantly) to increase SBP but decrease DBP. However, among subjects whose sodium intake was in excess of 257mmol/day, a 100 mmol/day increase in sodium intake was significantly (p=0.04) associated with a 3.3 mmHg increase in SBP. Conclusion Salt intake among Nigerians is higher than the recommended. The impact of sodium intake on BP appears to be evident only among individuals with high salt intake. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Wellcome Trust

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