Open ecosystems: ecology and evolution beyond the forest edge / William J. Bond

Incluye bibliografía (página 155-174 e índice (página 175-178

1 Introduction to open ecosystems: a global anomaly and a local example.. 1.1 Introduction.. 1.2 Fynbos shrublands: an example.. 1.2.1 Climate does not explain the absence of forests.. 1.2.2 The dominance of fynbos is not a consequence of deforestation.. 1.2.3 Forests are not excluded from fynbos by low nutrient soils.. 1.2.4 Fire and the origin and maintenance of open ecosystems.. 1.3 Open ecosystems in wider context.. 1.4 Geographic scope and terminological difficulties.. 1.5 History of research.. 1.5.1 Consumer control: fire and open ecosystems.. 1.5.2 Consumer control: herbivores and open ecosystems.. 1.5.3 New developments.. 1.6 Book structure.. 2 The pattern of open ecosystems and the climates in which they occur.. 2.1 Introduction.. 2.2 Climate explanations for the distribution of biomes.. 2.2.1 Examples of climate-vegetation correlations.. 2.3 Climate zones where ecosystems are uncertain.. 2.4 Tropical and subtropical regions.. 2.5 Temperate and boreal regions.. 2.5.1 Local studies.. 2.5.2 Mapping the spatial extent of temperate and boreal open ecosystems.. 2.5.3 Remote sensing of temperate and boreal trees.. 2.6 Beyond correlations.. 2.6.1 Dynamic Global Vegetation Models (DGVMs and DVMs.. 2.6.2 Southern African case study.. 2.6.3 Simulating world vegetation.. 2.7 Explanations for uncertain ecosystems.. 2.7.1 Are uncertain ecosystems merely the product of deforestation?.. 3 Uncertain ecosystems: the conceptual framework.. 3.1 Introduction.. 3.2 The carrying capacity for trees.. 3.3 Explanations for open, low biomass ecosystems: Bottom-up factors.. 3.3.1 Climate extremes.. 3.3.2 Hostile soils.. 3.3.3 Physical disturbance.. 3.4 Anthropogenic disturbance and open, low biomass ecosystems.. 3.5 Consumers and open, low biomass ecosystems.. 3.5.1 The green world hypothesis.. 3.5.2 Consumers that escape predation.. 3.5.3 Fire as a generalist herbivore.. 3.5.4 A multi-coloured world

3.6 Integrating top-down and bottom-up processes.. 3.7 Open ecosystems and succession mechanisms.. 3.8 Alternative stable states.. 3.8.1 Testing ASS.. 3.8.2 Alternative hypotheses.. 3.8.3 Experiments.. 3.8.4 Stability.. 3.8.5 Patterns from space.. 3.9 Implications of ASS theory.. 3.10 Summary.. 4 The nature of open ecosystems.. 4.1 Introduction.. 4.2 Diversity, endemism, and the antiquity of open ecosystems.. 4.3 Tropical grassy biomes.. 4.3.1 The grasslands of Madagascar: anthropogenic or ancient?.. 4.3.2 Southern grasslands of the USA.. 4.4 North temperate floras.. 4.5 A global perspective: open ecosystem biodiversity hotspots.. 4.5.1 Forests versus savannas: an intercontinental comparison.. 4.6 The diversity of open ecosystems.. 4.7 Functional traits in a trophically structured world: a framework.. 4.7.1 Green versus black and brown world traits (closed versus open ecosystems.. 4.7.2 Black world traits.. 4.7.3 Grass-fuelled surface fire regimes.. 4.7.4 Underground trees: geoxylic suffrutices.. 4.8 Crown fire systems.. 4.9 Old-growth grasslands.. 4.10 Brown world traits: herbivory responses.. 4.10.1 Woody plants.. 4.10.2 Herbaceous plants.. 4.11 Open habitat faunas.. 4.11.1 Species richness.. 4.11.2 Forest/open ecosystem mosaics.. 4.11.3 Functional traits.. 4.11.4 Mammals.. 4.12 Summary.. 5 The origins of closed and open ecosystems: Fossils and phytogenies.. 5.1 Introduction.. 5.2 Exploring the past.. 5.2.1 Fossils.. 5.2.2 Phylogenies.. 5.3 The early origin of forests.. 5.4 The Cretaceous and the emergence of the flowering plants.. 5.4.1 The attributes of early angiosperms.. 5.4.2 Dinosaurs and the spread of the angiosperms in the Cretaceous.. 5.4.3 Fire and the spread of angiosperms in the Cretaceous.. 5.4.4 Phylogenetic evidence for fire-adaptive traits in the Cretaceous.. 5.5 The first angiosperm-dominated forests.. 5.6 The Cenozoic: the age of mammals

5.7 The origin of grasslands: another angiosperm revolution.. 5.8 The origin of savannas.. 5.8.1 C4 photosynthesis and atmospheric C02.. 5.8.2 The role of consumers: fire.. 5.8.3 Climate, fire, C02 interactions.. 5.8.4 The role of consumers: mammals.. 5.9 Summary.. 5.9.1 The relevance of geological history of uncertain ecosystems.. 6 Soils and open ecosystems.. 6.1 Introduction.. 6.1.1 Hypotheses on the role of soils in shaping ecosystems.. 6.2 Physical controls on forest development.. 6.2.1 Waterlogging.. 6.2.2 Maximum rooting depth as a global constraint on trees.. 6.3 Chemical controls on forest development.. 6.3.1 Correlative studies.. 6.3.2 Plant-soil feedbacks.. 6.4 Sampling soils for ecological studies.. 6.4.1 Which nutrients?.. 6.5 Why should nutrients influence forest/open ecosystem distribution?.. 6.5.1 Hypotheses for soil nutrient dependence.. 6.5.2 Nutrient constraints on tree growth.. 6.5.3 Nutrient/fire interactions.. 6.6 Summary of soil effects.. 7 Fire and open ecosystems.. 7.1 Introduction.. 7.2 Hypotheses on the role of fire in shaping ecosystems.. 7.3 The spatial domain of fire as a consumer.. 7.4 Patterns of global fires: pyromes.. 7.4.1 Convergence and divergence of pyromes.. 7.5 Evidence for fire-maintained open ecosystems.. 7.5.1 Patterns.. 7.5.2 Manipulative studies.. 7.5.3 Fire suppression in tropical and subtropical grassy ecosystems.. 7.5.4 Fire suppression in woody and grassy temperate ecosystems.. 7.6 Evidence for fire-maintained open ecosystems: adding fire.. 7.7 Alternative stable states.. 7.7.1 Pyrophilic versus pyrophobic ecosystems.. 7.7.2 Feedbacks maintaining states: flammability.. 7.7.3 Feedbacks maintaining states: soils.. 7.7.4 Stability of states.. 7.7.5 Regime shifts.. 7.8 Life at the edge.. 7.9 Summary.. 8 Vertebrate herbivory and open ecosystems.. 8.1 Introduction.. 8.2 Overgrazing, degradation, and other value-laden terms

8.3 Examples of herbivore impacts.. 8.3.1 Exclosure experiments: temperate and boreal forests.. 8.3.2 Exclosure experiments: savannas.. 8.3.3 Natural experiments.. 8.4 Why herbivores impact plant populations.. 8.4.1 Factors influencing stem loss.. 8.4.2 Mechanical damage.. 8.4.3 Simulation models: putting herbivores into dynamic vegetation models (DVMs.. 8.5 Heterogeneity in herbivore impacts.. 8.5.1 Which herbivores?.. 8.5.2 Which plants?.. 8.6 Examples of brown world.. 8.7 Alternative states and regime shifts.. 8.7.1 Herbivory and fire as competing consumers.. 8.7.2 Stability of states and regime shifts: paleoecological evidence.. 8.8 Summary and conclusion.. 9 The future of open ecosystems.. 9.1 The end of savannas?.. 9.1.1 C02 effects.. 9.1.2 Woody encroachment.. 9.2 The future of consumers that maintain open ecosystems.. 9.2.1 The end of savannas? Fire management.. 9.2.2 The end of savannas? The future of the megafauna.. 9.2.3 The expansion of open woody ecosystems? Megafires and their control.. 9.2.4 Large fires and land-use change.. 9.3 Invasives and open ecosystems.. 9.4 Habitat transformation.. 9.5 Carbon sequestration, afforestation, and reforestation.. 9.5.1 Global tree-planting programmes.. 9.5.2 Will afforestation of open ecosystems cool the world?.. 9.6 Conclusions 152 References.. Index

This book explores the geography, ecology, and antiquity of 'open ecosystems', which include grasslands, savannas, and shrublands. They occur in climates that can support closed forest ecosystems and often form mosaics with forest patches. With the aid of remote sensing, it is now clear that open ecosystems are a global phenomenon and occur over vast areas in climates that could also support forests. This book goes beyond regional narratives and seeks general explanations for their existence. It develops the theme of open ecosystems as being widespread and ancient, with a distinct biota from that of closed forests. It examines hypotheses for their maintenance in climate zones favouring the development of forests, including fire, vertebrate herbivory, and soils hostile for tree growth. Open Ecosystems: ecology and evolution beyond the forest edge provides an accessible introduction for graduate students and researchers of open (non-forested) ecosystem ecology in departments of ecology, geography, and environmental science. It will also be of relevance and use to professional ecologists, biogeographers, and global change biologists requiring a concise, authoritative overview of the topic. eng