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

The Theory of Island Biogeography

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Soil Chemical Analysis

Climate change 2014 - Synthesis Report

This first report of the Millennium Ecosystem Assessment describes the conceptual framework that is being used in the MA. It is not a formal assessment of the literature, but rather a scientifically informed presentation of the choices made by the assessment team in structuring the analysis and framing the issues. The conceptual framework elaborated in this report describes the approach and assumptions that will underlie the analysis conducted in the Millennium Ecosystem Assessment. The framework was developed through interactions among the experts involved in the MA as well as stakeholders who will use its findings. It represents one means of examining the linkages between ecosystems and human well-being that is both scientifically credible and relevant to decision-makers. This framework for analysis and decision-making should be of use to a wide array of individuals and institutions in government, the private sector, and civil society that seek to incorporate considerations of ecosystem services in their assessments, plans, and actions.

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Ecosystems and human well-being: a framework for assessment

Despite the economic importance of mahoganies, few attempts have been made at genetic improvement, partly because of the high incidence of pest attack when mahoganies are grown in areas where they are native. A suggested domestication strategy for mahoganies is outlined, centred on the selection for pest resistance as part of a genetic improvement programme, the capture of selected genotypes using vegetative propagation techniques, and the deployment of selected material in appropriate silvicultural systems which optimise pest control. Current progress in developing such a strategy is described, including the assessment of genetic variation using field tests and molecular methods, and the development of vegetative propagation techniques with in vitro approaches. The importance of conserving genetic resources of mahogany species is highlighted, and the prospects for the future development of a domestication strategy are discussed. It is suggested that the development and implementation of such a strategy should be given high priority if a sustainable resource of mahogany is to be guaranteed in the 'future.

Domestication of mahoganies

Environmental characteristics have a major effect on the species composition of seasonally dry tropical forest. However, this effect has been little considered when describing secondary succession of this ecosystem. We tested the hypothesis that local environmental heterogeneity influences successional trajectories when high species richness is available. Changes in species composition and structure were described in 126 vegetation plots differing in successional stage and located along a topographical and soil nutrient gradient. Variation in community composition was partitioned between successional stage, environmental characteristics, and spatial structure using redundancy analyses. In addition, relationships between plot distance matrices for these factors were analysed by means of Mantel tests. High species turnover was observed during succession and species composition similarity was higher among late successional forest than among early and intermediate forests. A higher portion of variation in species composition was explained by environmental characteristics compared to successional stage, whereas the spatial structure of the data was weak. Our results suggest that in the region of study, variation in the successional trajectories is occurring owing to environmental heterogeneity, as well as to human disturbance and other unmeasured processes.

Resumen

Las caracteristicas ambientales tienen un efecto importante sobre la composicion floristica de los bosques secos tropicales. Sin embargo, este efecto ha sido poco considerado al describir la sucesion secundaria de este ecosistema. En este estudio probamos la hipotesis de que la heterogeneidad ambiental influye en las trayectorias sucesionales cuando se presenta una alta diversidad de especies. Se describieron cambios en la estructura y composicion de 126 parcelas de vegetacion diferenciadas en etapa sucesional y ubicadas a lo largo de un gradiente topografico y de contenido de nutrientes en el suelo. La variacion en la composicion de la comunidad fue particionada entre la etapa sucesional, las caracteristicas ambientales y la estructura espacial mediante analisis de redundancia. Adicionalmente, se analizo la relacion entre matrices de distancia de las parcelas para estos factores mediante test de Mantel. Se observo un alto recambio de especies entre etapas sucesionales y la similitud en la composicion fue mayor entre parcelas de etapa tardia que entre parcelas de etapas intermedia y temprana. Una mayor porcion de la variacion en composicion fue explicada por las caracteristicas ambientales en comparacion con la etapa sucesional mientras que la estructura espacial de los datos fue debil. Nuestros resultados sugieren que en el area de estudio se presenta variacion en las trayectorias sucesionales en relacion a las variables ambientales, asi como al disturbio humano y otros procesos no considerados.

Environmental Heterogeneity Influences Successional Trajectories in Colombian Seasonally Dry Tropical Forests

Ecological thresholds, which represent points of rapid change in ecological properties, are of major scientific and societal concern. However, very little research has focused on empirically testing the occurrence of thresholds in temperate terrestrial ecosystems. To address this knowledge gap, we tested whether a number of biodiversity, ecosystem functions and ecosystem condition metrics exhibited thresholds in response to a gradient of forest dieback, measured as changes in basal area of living trees relative to areas that lacked recent dieback. The gradient of dieback was sampled using 12 replicate study areas in a temperate forest ecosystem. Our results provide novel evidence of several thresholds in biodiversity (namely species richness of ectomycorrhizal fungi, epiphytic lichen and ground flora); for ecological condition (e.g. sward height, palatable seedling abundance) and a single threshold for ecosystem function (i.e. soil respiration rate). Mechanisms for these thresholds are explored. As climate-induced forest dieback is increasing worldwide, both in scale and speed, these results imply that threshold responses may become increasingly widespread.

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Thresholds of biodiversity and ecosystem function in a forest ecosystem undergoing dieback.

Information on the dispersal ability of invertebrate species associated with woodland habitats is severely lacking. Therefore, a study was conducted examining the movement patterns of wood cricket (Nemobius sylvestris) (Orthoptera: Gryllidae) on the Isle of Wight, UK. Juvenile (i.e. nymphs) and adult wood crickets were released and observed over time within different ground surface substrates. Their movement paths were recorded and subsequently analysed using random walk models. Nymphs were found to move more slowly than adults did; and, when given a choice, both nymphs and adults showed a preference for moving through or over leaf litter compared to bare soil or grass. A correlated random walk (CRW) model accurately described the movement pattern of adult wood crickets through leaf litter, indicating a level of directional persistence in their movements. The estimated population spread through leaf litter for adults was 17.9 cm min-1. Movements of nymphs through leaf litter could not accurately be described by a random walk model, showing a change in their movement pattern over time from directed to more random movements. The estimated population spread through leaf litter for nymphs was 10.1 cm min-1. The results indicate that wood cricket adults can be considered as more powerful dispersers than nymphs; however, further analysis of how the insects move through natural heterogeneous environments at a range of spatio-temporal scales needs to be performed to provide a complete understanding of the dispersal ability of the species.

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Movement analyses of wood cricket ( Nemobius sylvestris) (Orthoptera: Gryllidae)

The effect of inoculum pressure on disease tolerance was studied on a range of spring barley genotypes by manipulating the quantity of spores being deposited on field plots from surrounding plots. Genotypes included previously selected tolerant and non-tolerant types and the modifying effects of fertilizer levels were also studied. Under low fertilizer and normal' inoculum pressure and cspecially high fertilizer and high inoculum pressure conditions, where host and pathogen development were likely to be near equilibrium, designation of barley genotypes as tolerant or non-tolerant was more reliable than under the other conditions rested. Single trials were not reliable for designating tolerance.

Adrian C. Newton

Papers

Domestication of mahoganies

Environmental Heterogeneity Influences Successional Trajectories in Colombian Seasonally Dry Tropical Forests

Thresholds of biodiversity and ecosystem function in a forest ecosystem undergoing dieback.

Movement analyses of wood cricket ( Nemobius sylvestris) (Orthoptera: Gryllidae)

The effect of powdery mildew inoculum pressure and fertilizer levels on disease tolerance in spring barley.