Colin R. Townsend

Abstract: A revised and updated edition of this textbook. As before the study of plant and animal ecology is fully integrated and mathematical and laborotory studies are described where necessary. Examples drawn from real ecological systems ilustrate the complexity of this subject and the involvement of diverse areas: descriptive natural history, physiology, behaviour, field experimentation and mathematical modelling. The authors attempt to encourage the reader to combine all the above facets, so that a balanced view emerges. Emphasis is placed on the clear presentation of mathematical aspects and the material aims to be accessible to the undergraduate with little experience and also stimulating to practising ecologists. This new edition contains two new chapters both of which consider areas of applied ecology which are relevant to contemporary global issues. The first considers the control of abundance; on the one hand the limiting of pest and weed populations, on the other, maintaining the biological diversity of endangered species. The second considers large areas as an extension of the discussion of communities. These "ecosystems" in the newest sense of the word are an important field of study when considering some of the important environmental problems facing mankind.

Abstract: Preface.Introduction.Part 1. ORGANISMS .1. Organisms in their environments: the evolutionary backdrop.2. Conditions.3. Resources.4. Life, death and life histories.5. Intraspecific competition.6. Dispersal, dormancy and metapopulations.7. Ecological applications at the level of organisms and single-species populations Part 2. SPECIES INTERACTIONS.8. Interspecific competition.9. The nature of predation.10. The population dynamics of predation.11. Decomposers and detritivores.12. Parasitism and disease.13. Symbiosis and mutualism.14. Abundance.15. Ecological applications at the level of population interactions Part 3. COMMUNITIES AND ECOSYSTEMS .16. The nature of the community.17. The flux of energy through ecosystems.18. The flux of matter through ecosystems.19. The influence of population interactions on community structure.20. Food webs.21. Patterns in species richness.22. Ecological applications at the level of communities and ecosystems.References.Organism Index.Subject Index

Abstract: SUMMARY 1 This paper focuses on the premise that the habitat provides the templet upon which evolution forges characteristic species traits. Alternative hypotheses are that there are historic and phylogenetic constraints on the match between organism and environment. 2 In our analysis of river systems, as one dimension of the templet we choose temporal heterogeneity and assume some relationship between this and the frequency of disturbance. The second dimension is spatial heterogeneity in the physicochemical environment and we pay particular attention to the way such variation can ameliorate the influence of disturbances through the provision of refugia. 3 We derive predictions about the traits of species, including size, generation time, reproductive tactics, body form, mobility and potential for regeneration, that are likely to occur in particular regions of the two-dimensional templet. We also present predictions about community-level characteristics such as number of species per resource category and total species richness. The general predictions are intended to apply to a wide range of plants, micro-organisms and animals, provided the measurements have been made at a scale appropriate to them. 4 Hypotheses can be tested by comparing traits predicted for particular habitats, whose spatial and temporal heterogeneity have been quantified, with those actually observed. If the fit turns out to be good, we will be able to conclude that the habitat templet approach offers a sound framework within which to pose questions in river ecology.

Abstract: Stream ecologists are faced with the problem of recognizing patterns in community organization and explaining the processes that determine these patterns. I argue that streams con- form reasonably closely to the patch dynamics explanation of community organization which emphasizes temporal phenomena and focusses on the importance of history and chance. Even where competition or predation have been shown to play a role in shaping stream communities, the temporal phenomena of disturbance and colonization are invariably also of fundamental importance. In most cases, temporal variation is probably the factor of overriding significance, and species with weedy characteristics are a particularly prominent feature of streams. I highlight the critical role played by refugia as sources of recolonization after spates, and therefore as buffers against distur- bance. A theoretical framework based on the patch dynamics view of community ecology may provide a unifying theme in stream ecology.

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Abstract: An essential textbook for any student or researcher in biology needing to design experiments, sample programs or analyse the resulting data The text begins with a revision of estimation and hypothesis testing methods, covering both classical and Bayesian philosophies, before advancing to the analysis of linear and generalized linear models Topics covered include linear and logistic regression, simple and complex ANOVA models (for factorial, nested, block, split-plot and repeated measures and covariance designs), and log-linear models Multivariate techniques, including classification and ordination, are then introduced Special emphasis is placed on checking assumptions, exploratory data analysis and presentation of results The main analyses are illustrated with many examples from published papers and there is an extensive reference list to both the statistical and biological literature The book is supported by a website that provides all data sets, questions for each chapter and links to software

Abstract: Predation has long been implicated as a major selective force in the evolution of several morphological and behavioral characteristics of animals. The importance of predation during evolutionary ti...

Abstract: We have systematically made a set of precisely defined, single-gene deletions of all nonessential genes in Escherichia coli K-12. Open-reading frame coding regions were replaced with a kanamycin cassette flanked by FLP recognition target sites by using a one-step method for inactivation of chromosomal genes and primers designed to create in-frame deletions upon excision of the resistance cassette. Of 4288 genes targeted, mutants were obtained for 3985. To alleviate problems encountered in high-throughput studies, two independent mutants were saved for every deleted gene. These mutants-the 'Keio collection'-provide a new resource not only for systematic analyses of unknown gene functions and gene regulatory networks but also for genome-wide testing of mutational effects in a common strain background, E. coli K-12 BW25113. We were unable to disrupt 303 genes, including 37 of unknown function, which are candidates for essential genes. Distribution is being handled via GenoBase (http://ecoli.aist-nara.ac.jp/).

Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.