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Techniques for surveying exploited species

E. J. Milner-Gulland and Marcus Rowcliffe

in Conservation and Sustainable Use: A Handbook of Techniques

This chapter summarizes the methods available for estimating the population parameters that may be needed to assess biological sustainability, including population abundance, population and ... More

This chapter summarizes the methods available for estimating the population parameters that may be needed to assess biological sustainability, including population abundance, population and individual growth rates, rates of survival and productivity, and patterns of movement and distribution in space. The emphasis is on the need to sample populations effectively, and on understanding the strengths and weaknesses of a wide range of available survey methods. This provides a basis for selecting the most appropriate methods in a given situation, and for assessing how much effort will be required to get useable data. Extensive links are provided to detailed information on analytical methods, including software and online resources.Less

Adult Mortality and Modern Growth

Davide Fiaschi and Tamara Fioroni

Matteo Cervellati and Uwe Sunde (eds)

in Demographic Change and Long-Run Development

This chapter explores the role of increased adult longevity and technological progress in the transition from Malthusian equilibrium to modern growth. Empirical evidence suggests a general upward ... More

This chapter explores the role of increased adult longevity and technological progress in the transition from Malthusian equilibrium to modern growth. Empirical evidence suggests a general upward trend in life expectancy at birth and in adult survival rate of countries and a positive correlation between these two variables and income. A first strand of literature investigates the causes of mortality decline in western countries. Scholars can be divided into two main groups: the first attributes the observed mortality decline mainly to income growth via better nutrition, and the second emphasizes the role of public health and sanitary intervention. Meanwhile, a second strand of literature explores various channels through which mortality decline affects income.Less

Helping Doctors and Patients Make Sense of Health Statistics

Gerd Gigerenzer

in Simply Rational: Decision Making in the Real World

Many doctors, patients, journalists, and politicians alike do not understand what health statistics mean, or they draw wrong conclusions without noticing. The causes of statistical illiteracy should ... More

Many doctors, patients, journalists, and politicians alike do not understand what health statistics mean, or they draw wrong conclusions without noticing. The causes of statistical illiteracy should not be attributed to cognitive biases alone, but to the emotional nature of the doctor–patient relationship and conflicts of interest in the health care system. As the chapter shows, many sources of medical information intentionally or uninentionally use nontransparent information to persuade individuals, with serious consequences for personal health. Without understanding the numbers involved, the public is susceptible to political and commercial manipulation of their anxieties and hopes, which undermines the goals of informed consent and shared decision making.Less

Disease as a Potential Factor in Population Changes

Charles J. Krebs

in Population Fluctuations in Rodents

This chapter discusses diseases as the most likely cause for rodent population fluctuations. It first describes a study carried out on vole tuberculosis and population fluctuations, and then ... More

This chapter discusses diseases as the most likely cause for rodent population fluctuations. It first describes a study carried out on vole tuberculosis and population fluctuations, and then discusses the impact of parasitism and disease on the survival rates of small rodents. The chapter also presents two models that illustrate how the interaction of disease with other factors causes population declines.Less

Water vole restoration in the Upper Thames

Tom P. Moorhouse, Merryl Gelling, and David W. Macdonald

in Wildlife Conservation on Farmland Volume 1: Managing for nature on lowland farms

A replicated reintroduction experiment of water voles Arvicola terrestris in the Upper Thames was undertaken to reverse the species’ decline, and to learn lessons for future reintroductions. Cohorts ... More

A replicated reintroduction experiment of water voles Arvicola terrestris in the Upper Thames was undertaken to reverse the species’ decline, and to learn lessons for future reintroductions. Cohorts of forty-four water voles were released into twelve replicate 800 m stretches of river, each supporting a different habitat abundance. Five populations failed to establish or were later lost. Seven populations established and spread. At sites with higher vegetation abundance more of the release cohort survived, and post-establishment survival rates and population densities were higher. Prior to release, measures of immunocompetence were negatively correlated with group size, suggesting that individuals housed in larger groups were more physiologically stressed. These experimental reintroductions reversed the decline of water voles in the Upper Thames, and demonstrated that the release habitat should be the best available and that housing conditions pre-release must be optimized for the species in question.Less

Age-Grouping, Time-Specific Life-Tables, and Predictive Population Models

Peter A. Henderson

in Southwood's Ecological Methods

This chapter describes techniques to create life-tables for animals whose generations overlap widely. Age-grouping is a prerequisite for these methods, which have been most widely applied to ... More

This chapter describes techniques to create life-tables for animals whose generations overlap widely. Age-grouping is a prerequisite for these methods, which have been most widely applied to vertebrate populations. Age cannot be inferred from the developmental stage without reference to the environment. The speed of development may be temperature-dependent or influenced by factors such as oxygen and food availability. The methods for ageing animal groups, including invertebrates, fish, reptiles, amphibians, birds, and mammals, are reviewed. Time-specific life-tables, population modelling, and Leslie matrices are described. R code to analyze Leslie matrix dynamics is presented.Less

Scottish National Mortality and its Wider Context

Michael Anderson and Corinne Roughley

in Scotland's Populations from the 1850s to Today

In historical studies of Scottish mortality compared with other countries, expectation of life at birth is highly misleading because, until the early twentieth century, Scotland’s relatively low ... More

In historical studies of Scottish mortality compared with other countries, expectation of life at birth is highly misleading because, until the early twentieth century, Scotland’s relatively low infant mortality conceals the fact that age-specific death rates at almost all other ages were higher than the closest comparators in western Europe. Scotland has continued to have worse mortality at all ages because Scottish infant mortality, along with death rates at most other ages, failed to decline at the same rate as these other countries in Europe. Nevertheless, expectation of life at all ages did eventually improve at all ages (except most recently for young adult males), though at very varying speeds over time. This allowed survival rates to increase quite markedly, with very few children dying in childhood, most still-married couples living long enough to celebrate many more wedding anniversaries, and most children to know their grand- or even their great-grandparents.Less

A Statistical Study

David Gleicher

in The Rescue of the Third Class on the Titanic: A Revisionist History

This chapter tests the conclusions made over the course of the journal by studying the statistical likelihood of a passenger surviving the sinking of the ship. It is based around factors including ... More

This chapter tests the conclusions made over the course of the journal by studying the statistical likelihood of a passenger surviving the sinking of the ship. It is based around factors including class, gender, family, and age. The data is contrasted with Wyn Wade’s hypothesis that third class citizens had been conditioned throughout their lives to give up hope, and Walter Lord’s hypothesis that the ship’s design prevented third class escape. It confirms that the data matches the assertions made across previous chapters: the bias of the ship’s authorities toward the first and second classes mirrors the lower survival rate of third class men and women alike. It also provides the statistical equations used to formulate this conclusion.Less

In Conclusion

David Gleicher

in The Rescue of the Third Class on the Titanic: A Revisionist History

This final chapter concludes the findings of the journal. It states that contrary to the ‘popular story’ there exists no convincing evidence that passengers in the third class surged against ... More

This final chapter concludes the findings of the journal. It states that contrary to the ‘popular story’ there exists no convincing evidence that passengers in the third class surged against authority and disrupted evacuation efforts, and instead summarises available evidence to determine that third class men had severely restricted access to lifeboats. It cites the moral problem of the dangerous individuals theory as a major contributing factor to the crew’s bias against them.Less