austral ecology

Austral Ecology (2003) 28, 586–590 Book ReviewsLagoon: A Marine Ecosystem SimulationR. Cord-Ruwisch and E. I. Paling. CSIRO Publishing,Melbourne, 2002 [CD-ROM]. Price AUD$49.95.ISBN 0643066675.Lagoon is a computer simulation aimed at allowingusers to investigate the principles controlling equilibriain complex systems by carrying out virtual experi-ments. This conceptual tool was developed to providestudents with an interactive learning experience thatdemonstrates the importance of complexity in ecosys-tems. The simulation represents a ‘coastal embaymentor estuary’ governed by biological dynamic equilibria.Users can manipulate the model parameters to exploreeutrophication, competition for limiting nutrients,predator–prey relationships, and food chains.Well, so much for the synopsis. A PDF manual onthe CD-ROM describes how Lagoon can be used. Thesoftware is easy to install, and has modest systemrequirements (minimum: Windows 95, Pentium100 MHz, 16 MB RAM, CD-ROM drive 4ϫ). The program interface is colourful, pleasing to the eye, anduser-friendly. The software is largely mouse driven,with controls consisting of buttons and scroll bars, andpop-up menus giving descriptions of the controls.For someone with a childhood love and professionalinterest in the tidal parts of estuaries, but currently dry-footed research-wise, the opportunity to review thisprogram provided a most pleasant diversion. In thisregard though, the name Lagoon is deceptive. Theprogram consists of a relatively simple closed systemthat more closely resembles a coastal embayment thanan estuary, with parameterization of riverine inflow(and equivalent oceanic outflow) rate, but no para-meterization of tidal fluxes or salinity.Two types of physical variables can be altered: (i) therate of oxygen transfer from the atmosphere; and (ii)the rate and concentration of nitrate inflow. The pres-ence and growth of each of a range of organisms isgoverned by Michaelis–Menten kinetics and can bemanipulated by changing: (i) their maximum resourceuptake (or growth) rate and half saturation constant;(ii) the efficiency of conversion of resources consumedinto biomass; and (iii) the background biomass loss (ordeath) rate. The organisms, forming a linear foodchain, consist of primary producers (green algae),grazers (zooplankton eats green algae), carnivores(shark eats fish eats krill eats zooplankton), and decom-posers (bacteria regenerate nitrogen). Competitionbetween green algae and blue-green algae can also besimulated.The simulation has a set of seven different pre-specified simulations, which provide scenarios of increasing complexity. Sticking to the clear and (mostly) easy to follow instructions, I began by running ‘scenario 1’, which consisted of a simulation with just one green algal culture, and worked up to more com-plex scenarios. An appendix to the manual provides some useful problems for users to work through, which explore the model parameters and theoretical relation-ships and bring users to conduct virtual experiments to test their own hypotheses.The simple models underlying the growth of the simulated organisms are set out in equations given in the manual. It took some effort to make the connection between these and the simulation, particularly as the explanation in the manual is broken into two sections, and contains some minor errors. I found myself creating an excel spreadsheet to see how the various terms were related. User preference here may in part depend on whether you are the kind of person who finds it easy to synthesize information presented pictorially (visual learner), or (like me) like to get a handle on concepts by doing the sums yourself. Lagoon is an easy-to-use tool that would enhance undergraduate teaching at minimal cost. Such computer-based interactive teaching tools enable students to take responsibility for their own learning, through a hands-on experience and can be particularly valuable for distance learners, and in contexts where there has been a rationalization of teaching support relative to student numbers. Lagoon would comple-ment, but not substitute for, interactive learning experi-ences in the form of real field data collection and analysis, and the manipulation of strategic models (simple, mathematically tractable and formulated to identify ecological principles such as density-dependence) of populations in spreadsheets. The simulation model is a fun introduction to concepts such as resource uptake kinetics, food webs, water quality, and stability–diversity relationships. It achieves its goal of demonstrating the importance of complexity in ecosystems. Used as an undergraduate introduction, Lagoon may encourage students to take later year courses in aquatic and/or population ecology. These could all be seen as very important goals, given the latest Exxon Valdez-style disaster off the coast of Spain.ROCHELLE CHRISTIANSchool of Biological SciencesUniversity of CanterburyChristchurch, New ZealandBOOK REVIEWS587Flammable Austr alia. The Fir e Regimes and Biodiversity of a ContinentRoss A. Bradstock, Jann E. Williams and Malcolm A.G ill (eds.). Cambridge University Press, Cambridge, 2002, ix + 462 pages. Price AUD$150.00. ISBN 0521 80591 0.Flammable Australia. The Fire Regimes and Biodiversity of a Continent is an excellent successor to Fire and the Australian Biota(Gill A.M.,Groves R.H.&Noble I. R., eds. (1981) Australian Academy of Science, Canberra). Its chapters, 18 in all, were written by leading researchers and were peer-reviewed by others. With 30 contributors and 21 reviewers, it is a major ecological work. Four of its contributors also con-tributed to G ill et al. (1981), including Malcolm G ill himself, who was one of a trio of editors of both books. This book will be as seminal and stimulating to Australian research in fire ecology over the next two decades, as Fire and the Australian Biota has been over the last two.During the last two decades, fire ecology has made significant advances, particularly in Australia. Con-currently, the term biodiversity has come into general use, and the Australian continent is now recognized as one of the world’s most important centres of bio-diversity. Increasingly, the value has been recognized of analysing responses of flora, fauna and microorganisms to regimes of recurrent fires, rather than to single fire events, however spectacular and newsworthy single events might be.The basic groundwork of defining fire regimes and recognizing their components was laid two decades ago, as was that of classifying species according to responses to various fire regimes across the various stages of their life cycles. Over the last 20 years, understanding fire regimes and species responses has progressed in a range of Australian ecosystems. Also, in some ecosystems, the temporal and spatial variation of fire regimes is being increasingly understood. Such understanding, together with knowledge of responses of critical species, gives insight into how native bio-diversity may be maintained under various fire regimes, and is invaluable in conserving biodiversity in fire-prone landscapes. How such insight is derived and used in conserving biodiversity is critically and well explored in Flammable Australia. The Fire Regimes and Biodiversity of a Continent.The book firstly describes variation in biodiversity and fire regimes of the continent back through time, as far as evidence permits, to the start of the T ertiary. It then looks at the implications of future climatic changes for altered fire regimes and biodiversity. A chapter examines fire properties and the imprint of fire in heterogeneous landscapes, followed by a chapter seeking to understand fire regimes across landscapes through modelling, tested (as far as possible) against records of fires. Critical attributes of the life cycles of plants and animals are next examined in order to develop an understanding of population changes in fire-prone landscapes, followed by a consideration of spatial variability in fire regimes and its effects on recent and past vegetation.The central parts of the book cover fire regimes and biodiversity in the continent’s major ecosystems. Nine ecosystems are covered: the spinifex landscapes (which cover more than a quarter of the land surface of Australia), the temperate lowland grasslands of south-eastern Australia, heathlands, semiarid mallee, Acacia woodlands, the savannas of northern Australia, the woodlands of temperate Australia, the rainforest communities scattered across northern Australia, and the forested landscapes of southern Australia. The degree of understanding of fire regimes and their relationships with biodiversity varies among eco-systems. In temperate lowland grasslands and wood-lands, two ecosystems now vastly altered and reduced to remnant patches by agriculture and pastoralism, the fire regimes under which their native flora and fauna existed are now unknown, and this presents a basic difficulty in prescribing management to conserve their remaining biodiversity. In others, biodiversity manage-ment in relation to fire regimes is much more soundly based in scientific understanding.The final parts of the book cover the application of scientific understanding of fire regimes in managing biodiversity and ecosystem functions of semiarid and tropical pastoral lands, followed by a more general chapter setting out key approaches and principles in fire management and biodiversity conservation. The final chapter summarizes the history of the whole topic in Australia and raises pertinent issues that remain to be addressed in the investigation and management of fire regimes and biodiversity in the continent. Flammable Australia. The Fire Regimes and Biodiver-sity of a Continent is timely. It has been excellently conceived, written and edited; there are very few even minor glitches in it. It has collated pertinent research over the last two decades excellently, and clearly shows the way ahead for relevant research and management of biodiversity in thisflammable continent.It is a very worthy successor to its predecessor. This work should be read by every serious student of fire ecology no matter with what part of the earth they are concerned.PETER MYERSCOUGHInstitute of W ildlife ResearchSchool of Biological SciencesUniversity of Sydney, Sydney, Australia588BOOK REVIEWSExpe imental Design and Data Analysis fo BiologistsG. P. Quinn and M. J. Keough. Cambridge University Press, Cambridge, 2002, xvii + 537 pages. Price AUD$110.00 (paperback; hardback also available). ISBN 0521 00976 6.Some ecologists seem to carry formulae for fully factorial, nested, split-plot, repeated-measures ANOVA models around in the RAM portion of their brain. The majority I suspect, however, like me, do not. No part of my brain keeps these formulae for more than five minutes at a time! This review of Experimental Design and Data Analysis for Biologists consequently reflects my perspective as a general user of statistics, and reviews by qualified data analysts and biometricians should be sought if the reader wants a more informed opinion on the book’s statistical worth and accuracy. Do not be fooled by the title, the book is all about statistical analysis as it relates to parameter estimation and particularly hypothesis testing. Tips on good sampling and experimental design, while peppered throughout the book, need to be generally inferred from the assumptions and requirements of the different forms of analysis; only one chapter is dedicated to the topic (Chapter 7).Why beat around the bush? The book is excellent, even better for Australian biologists in that it uses so many Antipodean datasets as examples throughout (the authors are Melbourne-based academic ecologists). However, the book should also reach an appreciative international audience; it is by no means pitched solely at the Australian market. Already I have read compli-ments about it on specialist trans-national online dis-cussion groups (e.g. ORDNEWS). The writing style is good, authoritative and uncomplicated, and the text is well laid out with sensible use of sections and headings. Liberal use of figures, tables and boxes means that the text is relatively uncluttered by vast tracts of mathe-matical formulae, although they certainly consume some tables and boxes. The figures are simple and without frills, and so illustrate nicely the advice they give in the final chapter on the presentation of scientific results. Many of the boxes not overrun with mathe-matical symbols provide crisp insight into confusing statistical terms such as ‘generalized linear models’ (as opposed to ‘general’ linear models, see box 5.2) and ‘random effects mixed models’ (boxes 9.7 & 9.8). I noticed very few errors.The majority of the book either deals explicitly with ordinary least-squares regression and ANOVA in their myriad forms (general linear models: chapters 5–12) or prepares the reader for these parametric applications (chapters 1–4). The treatment of these topics is comprehensive, and if overwhelming at times, at least the material is well presented in a logical progression from the simple to the increasingly complex. Each chapter concludes with a useful simple summary,‘General issues and hints for analysis’, which I found helpful and reassuring.I suspect Experimental Design and Data Analysis for Biologists will be embraced by Australian academics who teach courses in statistical applications; I endorse the book for this use and the authors’ advice should be sternly heeded: no matter how well the instructor understands the statistical principles being taught, no matter how basic and simple the concepts and formulae may seem to her, always get the class involved with real datasets, computers and statistical packages. The authors state in the preface that the best way to learn the principles and proper application of statistics is by ‘doing’, and I concur emphatically. It was again rein-forced when I tried simply reading sections of the text on random effects and, separately, repeated-measures (RM) in general linear models. After a very short while reading these tracts, the formulae and words were blurring, and my mind was turning to more interesting topics (what to do that night). I chose these two topics as I have been modelling several ecological datasets recently requiring the specification of random terms in the REML (residual or restricted maximum likelihood estimation) environment, appropriate for unbalanced survey designs. I thought I should see what ‘random effects’ are and how they are treated differently from fixed effects statistically. I read the sections in Quinn and Keough, but it was incomprehensible to me until I opened my statspack, loaded a real dataset and followed the procedural advice in the accompanying statistical manual on how to run an ANOVA if one assumes a random effect for one of two orthogonal factors. Having thus seen and learnt that the error term used for calculating the F statistic differs (from the comparable fixed effects model), I went back to Quinn and Keough, and sure enough it now made sense, yet I had missed the vital point on first reading. Similarly with RM ANOVA, with which I had no prior experience, the text seemed incomprehensible until I worked through a dataset in a statistical package, taking the advice of the manual and a specialist book chapter on the topic (Scheiner S. M. & Gurevitch J. eds. (1993) Design and Analysis of Ecological Experiments Chapman & Hall, New Y ork). Again, having mastered the basics of RM at least, I returned to Quinn and Keough and they had the topic more than adequately covered, and with addi-tional sections for increasingly more complex RM designs.The authors have established a website on which they have loaded the datasets they use throughout the book to illustrate statistical applications, and so users are encouraged to run the same analyses themselves as part of the ‘learning by doing’ process. There are links to tertiary statistical course outlines, which the authors have generously posted.BOOK REVIEWS589Specialist topics receive sparse treatment, so other texts will be needed for advice on non-linear curve-fitting procedures (e.g. growth equations), recent advances in analysing complex datasets with correlated errors (e.g. spatial statistics), REML, GAM (general-ized additive models), non-parametric and randomiz-ation tests. However, these topics and many others rate at least a mention, and references to authoritative treatments are provided. Bayesian inference, multi-variate statistics (four chapters), generalized linear modelling and log-linear analyses (one chapter each) receive introductory treatment, and the authors take great care to indicate the limits of their own experience and knowledge. They also stress the importance of taking expert statistical advice whenever possible, that is, consult statisticians prior to designing a study to ensure the design is efficient, has sufficient power and will be tractable analytically.Used in conjunction with your favourite statistical handbook, and armed with the specialist biostatistical literature relevant to your particular field or current study, Quinn and Keough is a wonderful companion textbook, which would provide an eminently suitable basis for general undergraduate courses.JULIAN R.W. REIDCSIRO Sustainable Ecosystems Canberra, Australian Capital T erritory, Australia The Ecology of Wildlife DiseasesPeter J. Hudson, Annapaola Rizzoli, Bryan T. Grenfell, Hans Heesterbeek, Andy P. Dobson (eds). Oxford University Press, Oxford, 2002, xii + 197 pages. Price AUD$110.00. ISBN 0198506198.For many ecologists, the field of parasitology is perhaps dimly remembered as a grim, grey afternoon’s practical session dismembering still-warm coccidia-filled chick-ens and spasming wormy cockroaches. Biologists with an appreciation of the natural world committed certain obscure acanthocephalan life-cycles to memory, passed the requisite end-of-term exam and then opted for careers in the more glamorous disciplines of ecology, behaviour and population biology, without second thoughts to those afternoons of death. However, as the many contributing authors to The Ecology of Wildlife Diseases point out, the emergence of AIDS, Ebola and nv-Creutzfeld Jacob disease, the evolution of drug resistance, and the threats of disease to endangered wildlife populations have serious implications, which require a full understanding of the role of disease in wildlife ecology.The Ecology of Wildlife Diseases was generated from a workshop involving 50 epidemiologists that was convened in the Italian Alps, fuelled by fine wines and inspired by a fat cat (see the book’s preface), and which set out to unify current theories and themes of wildlife epidemiology. The book comprises nine chapters, all of them liberally interspersed with useful boxes that pro-vide concise examples of specific host–parasite case studies (e.g. amphibian declines), background theory (e.g. the immunocompetence theory) and explanations of mathematical models and statistical tests.After an introductory first chapter, chapter 2 discusses factors affecting the variation of parasitic infections in individual hosts. With concise sections discussing statistical measures of parasite dynamics (e.g. aggregation, negative binomial distributions, GLM) and current theory on heterogeneities in para-site load (e.g. sex-biases, host genetics), this chapter is a boon to burgeoning epidemiologists. Having established the impacts that parasites can have on individuals, chapter 3 asks whether disease, like pred-ation and competition, can actually regulate host populations.T ogether,chapters2and3provide a basic knowledge of wildlife disease ecology, assert the broader importance of parasites in ecology, and give a context with which to better understand the subsequent chapters.Chapters 4 and 5 deal with parasite community ecology, and microparasite transmission and persist-ence, respectively, and provide an understanding of the problems facing the management of disease. Spatial aspects of disease dynamics are discussed in chapter 6, which examines how geographical information systems and metapopulation theory can allow epidemiologists to improve their prediction and response to disease outbreaks in wildlife populations. Tick-borne infections have a special role in wildlife ecology because of the importance of zoonoses,animal diseases that can affect humans (e.g. Lyme’s disease and tick-borne encephalitis), and this forms the subject of chapter 7. The penultimate chapter (8) examines the complex role of pathogens in biological conservation. Parasites may play an important role in generating and main-taining biodiversity, but they have also been implicated in the extinction or decline of many diverse species (e.g. rainforest frogs, Hawaiian birds). Consequently, chapter 8 discusses how to manage wildlife pathogens. Finally, chapter 9 delineates areas of new research, and the current progress made in marrying mathematical theory with real wildlife management situations.The book’s editors profess to imagining the volume as a tribute to the former groundbreakers of disease ecology, and as vital reading to the epidemiologists of the future. As a member of the latter, flailing amongst lizards, blood parasites and non-normal distributions, I consider the book very welcome for its elegant synopses of current knowledge, advice on how to apply various scientific approaches, and because it is imbued with an enthusiasm for the potential of the field of disease590BOOK REVIEWSecology and an excitement about the many questions remaining. I think too that it has a broader appeal. Ecology lecturers should find the book appealing for the accessible potted histories of subjects, such as parasite-mediated mortality, or badgers and tubercu-losis, which nicely illustrate the roles of parasites in ecology. Furthermore, evolutionary ecologists previ-ously unaware of the relevance of disease will enjoy the book for its overview of the important role of parasites in determining host population dynamics.DAN J. SALKELDSchool of Tropical BiologyJames Cook UniversityT ownsville, Queensland, Australia。