Estimating Animal Abundance

The first accessible introduction to the many various wildlife assessment methods! This book uses a new approach that makes the full range of methods accessible in a way that has not previously been possible. Accompanied by free, user-friendly software to get some "hands-on" experience with the methods and how they perform in different contexts.

Originally published in 1982, this reprint of the second edition of The Estimation of Animal Abundance and Related Parameters has been described as the "bible" of the field. Censuses of living populations are required for many purposes in wildlife management, fisheries and pest control and they are essential in policy making for the protection of the environment. In this book Professor Seber, one of the leading experts in the field, explains in detail the methods that have been developed by ecologists for estimating animal numbers and related parameters such as mortality and birth rates. He insists on the importance of experimental design and describes a great variety of statistical techniques that are required in analyzing the data obtained. These designs and techniques are classified for easy reference according to the particular types of problems encountered by the field worker and the kind of information that is available. The assumptions underlying practical methods in current use are fully examined, together with procedures for testing their validity. Each method is demonstrated by at least one worked example; in all there are over 90 such examples, mostly using data obtained from natural or free-ranging populations around the world. Ecologists will find this book - the first full-length treatment of its subject - a sound statistical assessment of methods which in the past were frequently developed on an intuitive basis; while applied mathematicians will benefit no less from a study of the interaction between mathematics and biology in this important branch of statistics. Field workers will be stimulated and helped by the real-life examples and the practical nature of the work. "George Seber's book became an instant classic following its publication in 1973. It dealt comprehensively with previously published research on methods for estimating abundance and demographic parameters of animal populations. Professor Seber provided detailed reviews of methods that were originally published with adequate statistical development, and he provided derivations and development for intuitive estimators that had been initially presented by ecologists. The second edition of the book was published in 1982 and included substantive additional coverage of "new" developments that had occurred since 1973. The 1982 book has become a citation classic and can be found on the bookshelf of every serious animal population ecologist and every biostatistician dealing with animal population data. For the 20 years since its publication, it has remained the only book of its kind. Many important methodological developments have occurred in animal estimation problems since 1982, but virtually all such methods represent extensions of the initial methods described by Seber (1982). Several excellent monographs and books have been written over the last 2 decades that deal in detail with particular subsets of the material in Seber (1982). What is remarkable is that these recent contributions have not superseded Seber's book, but are best viewed as supplements to his original comprehensive treatment. Thus, Seber's (1982) book can still be found on the bookshelf of every serious animal population ecologist and biostatistician. Now, in 2002, it is surrounded on the bookshelf by a handful of related books and monographs, but it has not lost its relevance or importance and remains the most detailed, comprehensive treatment of methods to estimate animal abundance and related parameters." Jim Nichols, Patuxent Wildlife Research Center, U.S. Geological Survey, Laurel, MD Professor Seber, Professor Emeritus at the University of Auckland, is regarded as the world's foremost authority on statistical methods for estimating the size of animal populations. His early work on capture-recapture methods was groundbreaking and the Jolly-Seber method still forms the basis of most modern work, more than 30 years after his first paper on the method in 1962.

Our environment and natural food resources are continually coming under threat so that the monitoring of population trends is essential today. Whaling is a good example. Here politics and conservation often clash, and over the years more and more restrictions have been applied through the efforts of the International Whaling Commission in an endeavour to save some of our whale species from extinction. Localized fisheries also need to be monitored and quotas set each year. In some countries, sports fishing and hunting are popular so that information is needed about the populations being exploited in order to determine such things as the duration of hunting season and bag limits. Methods of estimating animal abundance have been developing steadily since the 1940s but over the last 20 years activity in this area has intensified and of this growth were two the subject has begun to blossom. At the centre of the authors of this book, David Anderson and Kenneth Burnham, who have widely published in this field. The need for computers in this area was soon recognized and David and Ken were joined by Jeffrey Laake who, with his computing expertise, helped to develop suitable software packages for implementing some of the new techniques. In the 1980s Stephen Buckland entered the arena and began to make his presence felt. Among other contributions, he firmly established the role of Monte Carlo and bootstrapping techniques in population estimation where the unique role of the computer could be fully exploited.

Information regarding population status and abundance of rare species plays a key role in resource management decisions. Ideally, data should be collected using statistically sound sampling methods, but by their very nature, rare or elusive species pose a difficult sampling challenge. Sampling Rare or Elusive Species describes the latest sampling designs and survey methods for reliably estimating occupancy, abundance, and other population parameters of rare, elusive, or otherwise hard-to-detect plants and animals. It offers a mixture of theory and application, with actual examples from terrestrial, aquatic, and marine habitats around the world. Sampling Rare or Elusive Species is the first volume devoted entirely to this topic and provides natural resource professionals with a suite of innovative approaches to gathering population status and trend data. It represents an invaluable reference for natural resource professionals around the world, including fish and wildlife biologists, ecologists, biometricians, natural resource managers, and all others whose work or research involves rare or elusive species.

This advanced text focuses on the uses of distance sampling to estimate the density and abundance of biological populations. It addresses new methodologies, new technologies and recent developments in statistical theory and is the follow up companion to Introduction to Distance Sampling (OUP, 2001). In this text, a general theoretical basis is established for methods of estimating animal abundance from sightings surveys, and a wide range of approaches to analysis of sightings data is explored. These approaches include: modelling animal detectability as a function of covariates, where the effects of habitat, observer, weather, etc. on detectability can be assessed; estimating animal density as a function of location, allowing for example animal density to be related to habitat and other locational covariates; estimating change over time in populations, a necessary aspect of any monitoring programme; estimation when detection of animals on the line or at the point is uncertain, as often occurs for marine populations, or when the survey region has dense cover; survey design and automated design algorithms, allowing rapid generation of sound survey designs using geographic information systems; adaptive distance sampling methods, which concentrate survey effort in areas of high animal density; passive distance sampling methods, which extend the application of distance sampling to species that cannot be readily detected in sightings surveys, but can be trapped; and testing of methods by simulation, so that performance of the approach in varying circumstances can be assessed.

This study concerns the use of distance sampling to estimate the density or abundance of biological populations. Line and point transect sampling are the primary distance methods. Here, lines or points are surveyed in the field and the observer records a distance to those objects of interest that are detected. The sample data are the set of distances of detected objects and any relevant covariates; however, many objects may remain undetected during the course of the survey. Distance sampling provides a way to obtain reliable estimates of density of objects under fairly mild assumptions. Distance sampling is an extension of plot sampling methods where it is assumed that all objects within sample plots are counted.