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

Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth's biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls. The scientific community has come to a broad consensus on many aspects of the re- lationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are struc- tured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth's ecosystems and the diverse biota they contain.

/pdf/effects-of-biodiversity-on-ecosystem-functioning-a-consensus-13j8vabcus.pdf

Effects of biodiversity on ecosystem functioning: a consensus of current knowledge

A doubling in global food demand projected for the next 50 years poses huge challenges for the sustainability both of food production and of terrestrial and aquatic ecosystems and the services they provide to society. Agriculturalists are the principal managers of global useable lands and will shape, perhaps irreversibly, the surface of the Earth in the coming decades. New incentives and policies for ensuring the sustainability of agriculture and ecosystem services will be crucial if we are to meet the demands of improving yields without compromising environmental integrity or public health.

/pdf/agricultural-sustainability-and-intensive-production-1h98l920tu.pdf

Agricultural sustainability and intensive production practices

Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.

/pdf/the-worldwide-leaf-economics-spectrum-1uikdmil76.pdf

The worldwide leaf economics spectrum

We discuss the physical and enzymatic bases of carbone isotope discrimination during photosynthesis, noting how knowledge of discrimination can be used to provide additional insight into photosynthetic metabolism and the environmental influences on that process

Carbon Isotope Discrimination and Photosynthesis

In this chapter, different approaches to the study of terrestrial ecosystems are introduced. The chapter is organised in two main parts: observations and experiments. For both of these general approaches, many examples are given from around the globe, introduced by typical research questions and illustrated with photos. Observations can be done at the level of whole ecosystems, either as single-site studies or as multisite studies within large networks, often using new technologies to measure variables of interest or to access tall canopies. Transects and chrono-sequences are introduced and critically discussed. Grid-based inventories and applications of remote sensing techniques complement the observational approaches. Natural experiments—that is, sudden disturbances and slow continuous forcing—are also discussed. On the other hand, experiments can be carried out by manipulating pools and processes, and also by manipulating environmental conditions. Examples range from transplant and space-for-time experiments to fertilisation and irrigation trials and to roof and free-air carbon dioxide enrichment experiments. The relevance of appropriate controls and the existence of hidden treatments are discussed. Biodiversity experiments are explained in detail, as are experiments of management and changes in land cover. To conclude this chapter, artificial ecosystems are introduced and their benefits are explored.

Approaches to study terrestrial ecosystems

Der Einfluß des geologischen Untergrundes, der Hangneigung, der Feldgröße und der Flurbereinigung auf die Heckendichte in Oberfranken

Within the area of its natural distribution in Southwest Africa, Welwitschia mirabilis has a higher ∂13 C value than C3 plants and a lower ∂13 C value than C 4 plants occuring in the same habitat. This indicates that Welwitschia m. fixes part of its carbon by crassulacean acid metabolism (CAM) when growing in its natural habitat. Measurements of ∂13 C values show the proportion of carbon fixed by CAM to be higher in the savanna zone than in the subtropical grassland zone. Even higher ∂13 C values were measured on Welwitschia m. in the coastal desert. There was no correlation between ∂13 C values and the ash content of plant material and with water stress indicating that these factors were not responsible for the observed shift in carbon metabolism. It was concluded, after an analysis of temperature conditions, that cool night temperatures were possibly responsible for promoting a greater portion of CAM in Welwitschia m. in the coastal desert as compared with savanna and subtropical grassland zones.

Ernst Detlef Schulze

Papers

Approaches to study terrestrial ecosystems

Der Einfluß des geologischen Untergrundes, der Hangneigung, der Feldgröße und der Flurbereinigung auf die Heckendichte in Oberfranken

Der Säurestoffwechsel von Welwitschia mirabilis Hook. Fil. Am Natürlichen Standort in der Namib Wüste

Über Kioto hinaus denken - Klimaschutz für das 21. Jahrhundert

Potentials and limitations of ecosystem analysis. Ecological studies 61.