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

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

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Experimental Design and Data Analysis for Biologists

Prediction of species' distributions is central to diverse applications in ecology, evolution and conservation science. There is increasing electronic access to vast sets of occurrence records in museums and herbaria, yet little effective guidance on how best to use this information in the context of numerous approaches for modelling distributions. To meet this need, we compared 16 modelling methods over 226 species from 6 regions of the world, creating the most comprehensive set of model comparisons to date. We used presence-only data to fit models, and independent presence-absence data to evaluate the predictions. Along with well-established modelling methods such as generalised additive models and GARP and BIOCLIM, we explored methods that either have been developed recently or have rarely been applied to modelling species' distributions. These include machine-learning methods and community models, both of which have features that may make them particularly well suited to noisy or sparse information, as is typical of species' occurrence data. Presence-only data were effective for modelling species' distributions for many species and regions. The novel methods consistently outperformed more established methods. The results of our analysis are promising for the use of data from museums and herbaria, especially as methods suited to the noise inherent in such data improve.

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Novel methods improve prediction of species' distributions from occurrence data

■ Abstract The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in different ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscape-scale process involving both habitat loss and the breaking apart of habitat. Results of empirical studies of habitat fragmentation are often difficult to interpret because (a) many researchers measure fragmentation at the patch scale, not the landscape scale and (b) most researchers measure fragmentation in ways that do not distinguish between habitat loss and habitat fragmentation per se, i.e., the breaking apart of habitat after controlling for habitat loss. Empirical studies to date suggest that habitat loss has large, consistently negative effects on biodiversity. Habitat fragmentation per se has much weaker effects on biodiversity that are at least as likely to be positive as negative. Therefore, to correctly interpret the influence of habitat fragmentation on biodiversity, the effects of these two components of fragmentation must be measured independently. More studies of the independent effects of habitat loss and fragmentation per se are needed to determine the factors that lead to positive versus negative effects of fragmentation per se. I suggest that the term “fragmentation” should be reserved for the breaking apart of habitat, independent of habitat loss.

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Effects of Habitat Fragmentation on Biodiversity

Statistics for Spatial Data.

Aim We assessed how avian biodiversity and above-ground carbon storage were related in different forest age-classes, including mature stands (> 100 years), in a managed, mixed-species eucalypt forest.



Location  Gippsland, south-eastern Australia.



Methods  In 50 2-ha stands ranging in age from ≤ 5 years to mature stands > 100 years, we undertook repeated avian surveys, performed detailed habitat measurements and estimated amounts of above-ground carbon. Extensive wildfire reduced the number of sites to 28 (seven in each of four age classes) upon which analyses and inferences were made. We also analysed data on carbon storage and some bird responses from previously published studies.



Results  Mature vegetation (> 100 years) had the greatest richness, abundance and biomass of birds. Key ecological resources, such as tree-hollows for nesting, generally occurred mostly in stands > 60 years. Avian richness per unit of above-ground carbon storage was relatively low for stands of 20–60 years. While above-ground carbon storage appeared to increase in a monotonic fashion as stands age and mature, there were quantum increases in all measures of avian biodiversity in mature stands (> 100 years).



Main conclusions  Our results suggest that carbon is organized in a different way, with substantially greater biodiversity benefits, in very old stands. Mature vegetation simultaneously maximizes both avian biodiversity and above-ground carbon storage. These results bolster arguments for allocating highest priorities to the preservation of old-growth forest stands rather than alternative investments (e.g. reafforestation for carbon sequestration).

‘Ecologically complex carbon’– linking biodiversity values, carbon storage and habitat structure in some austral temperate forests

Aim Climate change has been linked to negative effects on vegetation, including drought-induced dieback. Large-scale dieback not only leads to considerable carbon emissions but often leads to loss of ecological resources. We investigated whether, and how, the structure, composition and carbon content changed over a period of extended drought (the ‘Big Dry’) in a much-modified forest ecosystem. We explored whether landscape configuration, management practice or soil type influenced vegetation change. Location The Box-Ironbark forests of south-eastern Australia. Methods In 2010, we remeasured 120 forest transects that had first been measured in 1997 by using identical field methods. Vegetation structure and composition were quantified. We used allometric growth models to estimate the expected increase in above-ground carbon (AGC) storage between 1997 and 2010; these estimates were compared with observed values.

The interaction between a drying climate and land use affects forest structure and above‐ground carbon storage

Humans have altered many floodplain ecosystems around the world by clearing vegetation, building towns and regulating river flows Studies discerning gene flow and population structure of floodplain-dwelling animals are rare yet are necessary for understanding the effects of human actions on native populations In south-eastern Australia, the yellow-footed antechinus (Antechinus flavipes) is the only carnivorous marsupial on many lowland floodplains, yet our knowledge of impacts of human activities is limited The control region of mitochondrial DNA and 11 microsatellite DNA markers were used to explore historic and current gene flow in A flavipes across and along the Murray River Simulations were carried out to test different migration models We found evidence for historic gene flow along and across the river but inferred that small towns and farmland or cleared floodplain sections restricted current gene flow along the river Populations along the river appear to be isolated, and should be maintained at large enough sizes to avoid genetic problems such as inbreeding depression and loss of evolutionary potential We also investigated whether 50-year-long maintenance of high water levels for irrigation in summer, at the time of juvenile dispersal, has led to restrictions in gene flow across the river We found no evidence for restrictions to gene flow across the river and suggest that large floods and dropping tree branches may aid dispersal across the river

Distinguishing past from present gene flow along and across a river: the case of the carnivorous marsupial (Antechinus flavipes) on southern Australian floodplains

Summary

1. Dispersal of propagules by waterbirds is thought to be important for wetland plants because of the abundance of birds and their frequent movements among aquatic habitats. Differences in bird characteristics (size, movement, feeding ecology) were expected to lead to different outcomes for plant dispersal.



2. We investigated heterogeneity in plant dispersal by ducks (Anas superciliosa, Anas gracilis, Anas castanea). We calculated the probability of transport of viable seeds by germinating propagules retrieved from feathers and feet (epizoochory) and the contents of the oesophagus, gizzard and lower gut (endozoochory).



3. The abundance and richness of seeds carried internally and externally did not differ among sympatric bird species. We used estimates from the literature of movements of Anas species to approximate dispersal kernels for the transport of plant propagules.



4. Heterogeneity in the abundance and movement ecology of disperser species will result in differing patterns and degrees of connectivity for wetland plant metacommunities. Sedentary waterfowl are likely to have an important role in replenishing propagules and connecting aquatic metacommunities over small distances. Nomadic waterfowl may facilitate long-distance dispersal. We discuss the implications of differences between duck species in movement patterns for connectivity of aquatic plant metacommunities across landscapes.

Do birds of a feather disperse plants together

Ideally, one seeks to assess landscapes for their capacity to sustain viable populations of all local species. This applies to much-affected landscapes and also to restored landscapes. In most circumstances, it is prohibitive to conduct full demographic and dispersal studies of many species of birds (or other taxa) at many sites, which typifies many conservation problems. Here I report upon outcomes of elicitations of views of expert ornithologists on how they would weight a range of breeding behaviours and evidence for success of breeding in remnants or replanted sites. Such consensus results potentially could be used by workers to assess how alternative conservation and management actions affect breeding success. While the data are tailored specifically to Australian woodland birds, the method can be adapted easily for other taxa and habitats. I also summarize some of the experts' main caveats on weightings.

Ralph Charles Mac Nally

Papers

‘Ecologically complex carbon’– linking biodiversity values, carbon storage and habitat structure in some austral temperate forests

The interaction between a drying climate and land use affects forest structure and above‐ground carbon storage

Distinguishing past from present gene flow along and across a river: the case of the carnivorous marsupial (Antechinus flavipes) on southern Australian floodplains

Do birds of a feather disperse plants together

Consensus weightings of evidence for inferring breeding success in broad‐scale bird studies