nach oben

2011 | Buch

Kapitel lesen Erstes Kapitel lesen

Tropical Rainforest Responses to Climatic Change

herausgegeben von: Mark Bush, John Flenley, William Gosling

Verlag: Springer Berlin Heidelberg

Buchreihe : Springer Praxis Books

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

Einloggen, um Zugang zu erhalten

Über dieses Buch

This updated and expanded second edition of a much lauded work provides a current overview of the impacts of climate change on tropical forests. The authors also investigate past, present and future climatic influences on the ecosystems with the highest biodiversity on the planet.

Tropical Rainforest Responses to Climatic Change, Second Edition, looks at how tropical rain forest ecology is altered by climate change, rather than simply seeing how plant communities were altered. Shifting the emphasis on to ecological processes, e.g. how diversity is structured by climate and the subsequent impact on tropical forest ecology, provides the reader with a more comprehensive coverage. A major theme of the book is the interaction between humans, climate and forest ecology. The authors, all foremost experts in their fields, explore the long term occupation of tropical systems, the influence of fire and the future climatic effects of deforestation, together with anthropogenic emissions. Incorporating modelling of past and future systems paves the way for a discussion of conservation from a climatic perspective, rather than the usual plea to stop logging. This second edition provides an updated text in this rapidly evolving field. The existing chapters are revised and updated and two entirely new chapters deal with Central America and the effect of fire on wet forest systems. In the first new chapter, the paleoclimate and ecological record from Central America (Lozano, Correa, Bush) is discussed, while the other deals with the impact of fire on tropical ecosystems. It is hoped that Jonathon Overpeck, who has been centrally involved in the 2007 and 2010 IPCC reports, will provide a Foreword to the book.

Inhaltsverzeichnis

Frontmatter

1. Cretaceous and Tertiary climate change and the past distribution of megathermal rainforests

Abstract

The history of megathermal (currently ‘‘tropical’’) rainforests over the last 30 kyr is now becoming relatively well-understood, as demonstrated by the many contributions in this volume. However, our perception of their longer-term history remains highly fragmentary. There is a real need for a better understanding of rainforest history on an evolutionary time scale, not only to have a better idea of the biological, geological, and climatic factors which have led to the development of the most diverse ecosystem ever to have developed on planet Earth, but also since the implications of rainforest history on an evolutionary time scale are inextricably linked to a plethora of other issues currently receiving wide attention. Determining the place and time of origin and/or radiation of angiosperms (which overwhelmingly dominate present day megathermal rainforests), establishing patterns of global climate change, clarifying the nature of global temperature gradients through time, understanding the successive switching from greenhouse to icehouse climates, global warming, patterns of dispersal of megathermal plants and animals, higher rank (ordinal) taxonomy and the nature of controls on global diversity gradients are but some issues which are being clarified with the better understanding of the long-term history of megathermal rainforests.

R. J. Morley

2. Andean montane forests and climate change

Abstract

The montane forest habitats of the Andes support exceptionally high biodiversity, with many species occupying narrow elevational ranges (e.g., Terborgh, 1977). These attributes, combined with the short migratory distances, often <30km separates the lowlands from the upper forest line, allows montane forests to be extremely sensitive monitors of climatic change.

M. B. Bush, J. A. Hanselman, H. Hooghiemstra

3. Climate and vegetation change in the lowlands of the Amazon Basin

Abstract

Data from palynology, taxonomy, and isotopic analyses, allied to climate models, reveal the complexity of the history of Amazon ecosystems. Evidence from these records suggests that Pleistocene climatic change was neither uniform nor synchronous across the basin, but that its effects were pervasive.

M. B. Bush, W. D. Gosling, P. A. Colinvaux

4. The Quaternary history of Far Eastern rainforests

Abstract

This region differs from those supporting tropical rainforest in other parts of the world in that it is less continental and geologically much more dynamic. It incorporates some major pieces of continental plate, but its center—the so-called ‘‘Maritime Continent’’ (Ramage, 1968)—is largely a complex interaction zone between the Asian and Australian Plates resulting from the continued movement of the Australian Plate into Southeast Asia (Metcalfe, 2002). The effects of tectonic and volcanic activity have resulted in mountain uplift, particularly in New Guinea, and formation of the volcanic island chain of Indonesia. Vulcanicity also occurs out into the Pacific beyond the ‘‘andesite line’’ where most ‘‘high’’ islands are volcanic and most ‘‘low’’ islands are coral islands developed on sunken volcanoes.

A. P. Kershaw, S. van der Kaars, J. R. Flenley

5. Rainforest responses to past climatic changes in tropical Africa

Abstract

In Africa the lowland rainforest occurs under significantly drier conditions than in other continents, within an average precipitation of 1,600 to 2,000mmyr_1, although higher rainfall is observed around the Atlantic coast of Cameroon, Gabon, and in the Central Zaire Basin. Seasonal distribution of precipitation is far from being uniform (White, 1983). Variations in the duration of the dry season follow the distance from the equator in both hemispheres and also along a west-to-east gradient. The Biafran Gulf is the only region where the minimum monthly precipitation value always exceeds the 50-mm threshold for the driest month, therefore experiencing no dry season.

R. Bonnefille

6. Prehistoric human occupation and impacts on Neotropical forest landscapes during the Late Pleistocene and Early/Middle Holocene

Abstract

This chapter presents a review of the evidence for human occupation and modification of the lowland neotropical forest during the pre-Columbian era. It examines some of the most important factors relating to the occupation and use of tropical landscapes by prehistoric human societies and updates the information presented in the 2006 edition of this book. Late Pleistocene through early and Middle Holocene temporal frames (c. 16 to 5 kcal yr bp) were covered most extensively in the first edition, as these were the periods during which humans colonized both hemispheres of the Americas and agricultural societies emerged and spread throughout the lowland tropical forest.

D. R. Piperno

7. The past, present, and future importance of fire in tropical rainforests

Abstract

The tropics bring to mind picturesque beaches and idyllic visions of seemingly endless tropical rainforests. Often overlooked, however, is that the tropics are also comprised of vast areas of savanna, montane grasslands, dry deciduous and dry thorn forests, as well as mangroves, deserts, wetlands, and a multitude of other ecosystems; many of these ecosystems burn frequently. The tropics cover one-third (33.7%) of the planet’s land surface. They contain over 40% of the world’s forests, the vast majority of all species, and are home to over 35% of the human population (Cochrane, 2009a). Satellite detections of thermal anomalies also show that the tropics experience more fires per year than anywhere else on Earth (Figure 7.1). In this region, where fire dominates many landcover types, sit the world’s richest storehouse of biodiversity within what appear to be nearly fire-immune tropical rainforests.

M. A. Cochrane

8. Ultraviolet insolation and the tropical rainforest: Altitudinal variations, Quaternary and recent change, extinctions, and the evolution of biodiversity

Abstract

Ultraviolet light occurs in three wavebands. UV-A is the longest waveband (>315 nm) which is close to visible light and is of limited biological significance. UV-B (280–315 nm) is damaging and mutagenic to living organisms. UV-C (<280 nm) is lethal to all life, but is fortunately absorbed in the stratosphere, so does not reach the surface of the Earth in sunlight. It is therefore toUV-B that we must turn our chief attention. This, like UV-C, is also partly absorbed by ozone in the stratosphere, but some reaches the Earth’s surface. Recent concerns about the ‘‘Ozone Hole’’ have focussed attention on polar regions, but in fact tropical regions have fairly low ozone concentrations in the stratosphere above them (Smith and Warr, 1991). The result is that, given their high overall insolation resulting from the low latitude, tropical regions have rather high UV-B levels.

J. R. Flenley

9. Climate change in the Amazon Basin: Tipping points, changes in extremes, and impacts on natural and human systems

Abstract

The Amazon River system is the single, largest source of freshwater on Earth and its flow regime is subject to interannual and long-term climate variability, which translate into large variations in downstream discharge (Richey et al., 1989; Marengo and Nobre, 2001; Marengo 2004, 2005, 2006, 2007; Milly et al., 2005, Marengo et al., 2008a, b; Cox et al., 2008; Zeng et al., 2008). To predict future climate (rainfall) change and consequent river variability an understanding of the physical mechanisms related to regional and large-scale atmospheric–oceanic–biospheric forcings is required. The temporal and spatial nature and impact of any variability in the hydrometeorology of the Amazon Basin must be considered in this context.

J. A. Marengo, C. A. Nobre, G. Sampaio, L. F. Salazar, L. S. Borma

10. Plant species diversity in Amazonian forests

Abstract

Looking at the Amazonian landscape from space one sees unbroken forest stretching from the eastern lowlands of Colombia south through Peru to Bolivia, and east from the Andes to the Atlantic Ocean. The expanse of trees—covering over half a billion hectares—is draped over a relatively flat landscape broken only by large rivers and human-induced habitat modification (Figure 10.1a).

M. R. Silman

11. Biogeochemical cycling in tropical forests

Abstract

Increased inputs of greenhouse gases have altered the composition of the atmosphere over the past 150 years (IPCC, 2001, 2007), resulting in shifts in temperature and precipitation around the globe. The scientific community has put an enormous effort into understanding the causes of these changes, and predicting future climate and the interactions between climate and the biosphere that may moderate or accelerate current trends. Most of the research on climate change has focused on boreal and north temperate ecosystems where temperature shifts are predicted to be the largest (IPCC, 2001, 2007). These ecosystems are often characterized by deep organic soils that present the potential for a strong positive feedback to climate change (Oechel et al., 1998; Vourlitis and Oechel, 1997; Hobbie et al., 2002).

M. E. McGroddy, W. L. Silver

12. The response of South American tropical forests to recent atmospheric changes

Abstract

Ecosystems worldwide are changing as a result of anthropogenic activities. Processes such as deforestation are physically obvious, but others, such as hunting and surface fires, are subtler but affect biodiversity in insidious ways (cf. Lewis et al., 2004a; Laurance, 2004). Increased rates of nitrogen deposition and increases in air temperatures and atmospheric CO2 concentrations are altering the environment of even the largest and most well-protected areas (e.g., Galloway and Cowling, 2002; Malhi and Wright, 2004). Anthropogenic atmospheric change will become more significant during this century, as CO2 concentrations reach levels unprecedented for the last 20 million or perhaps even 40 million years (Retallack, 2001; Royer et al., 2001). Nitrogen deposition rates and climates are predicted to move far beyond Quaternary envelopes (Galloway and Cowling, 2002). Moreover, the rate of change in all these basic ecological drivers is likely to be without precedent in the evolutionary span of most species on Earth today (Lewis et al., 2004a). This then is the Anthropocene: we are living through truly epoch-making times (Crutzen, 2002).

O. L. Phillips, S. L. Lewis, T. R. Baker, Y. Malhi

13. Ecophysiological response of lowland tropical plants to Pleistocene climate

Abstract

Climate changes associated with the Last Glacial Maximum (LGM, 21 kyr) are probably the most extreme that terrestrial vegetation, including tropical lowland ecosystems, have been forced to respond in over the past 100,000 years. The degree of tropical cooling can be reconstructed by paleoproxies that generally indicate a minimal cooling of 3_C and a maximum cooling of approximately 7_C (Guilderson et al., 1994; Stute et al., 1995; Mix et al., 1999; Behling and Negrelle, 2001; Mora and Pratt, 2001; Behling, 2002; Urrego et al., 2005; Punyasena et al., 2008; Blard et al., 2009; Williams et al., 2009). Some debate surrounds the degree of tropical decreases in glacial precipitation, primarily because precipitation patterns are strongly regional, and thus wide discrepancies in paleoprecipitation trends occur between different reconstructions. Despite this, a value of approximately 20% decrease in LGM rainfall is typically reconstructed from pollen-proxies in tropical catchments—such as the Amazonian Basin (Bush and Silman, 2004). Paleoclimate simulations of the South American monsoon during the LGM indicate an annual reduction in rainfall across Amazonia of between 25–35% relative to today (Cook and Vizy, 2006). Research also shows that glacial decreases in rainfall likely occurred in wet as opposed to dry seasonal months (Bush and Silman, 2004).

S. A. Cowling

14. Tropical environmental dynamics: A modeling perspective

Abstract

The impact of climatic change on tropical vegetation is of global and regional concern because of the high biodiversity and the feedbacks to the carbon, water, and nutrient cycles. Tropical ecosystem functioning is governed by complex systems, that, in spite of their diversities, share in common structures and characteristic states which can be modeled (Aassine and Jay, 2002). Records of fluctuating biotic and chemical characteristics from numerous sedimentary archives, including oceans (Guilderson et al., 1994), continental lakes, bogs, swamps (Hooghiemstra and van der Hammen, 1998; Behling and Hooghiemstra, 2000; Haberle and Maslin, 1998), and ice caps (Thompson et al., 1995), demonstrate that tropical environments change at a range of time scales. One of the most recent extremes of these variations concerns the 100,000 glacial–interglacial cycles associated with the Quaternary geological period (i.e., the past 2.6 million years). Climate change involves massive reorganisation of global climate systems with major impacts on ecosystem form and function giving rise to complex interactions between the atmosphere, geosphere, hydrosphere, and biosphere (Kohfeld and Harrison, 2000). Models are essential tools to assess the potential response of vegetation to climate change, particularly where large spatial and temporal scales are considered (Ostendorf, 2001). Such changes can also be documented by accessing sedimentary archives, whereas the nature and implications of such changes can be investigated through modeling. Models using a space for time substitution are based on rich and detailed spatial information and have a very high level of empiricism (Ostendorf, 2001).

R. Marchant, J. C. Lovett

15. Modeling future effects of climate change on tropical forests

Abstract

Alterations in climate (or even the natural variation within the current climate) can affect forest communities by altering the internal processes or by altering the proportions of different species in the forests. Experience in assessing the consequences of major climate change is based mostly on paleo-reconstructions for northern hemisphere forests responding to the climate warming that followed the last ice age. These reconstructions demonstrate that climate change also can alter forests by tearing them apart and re-assembling them in novel combinations of species. This process is dramatic in temperate zones and less well-documented but no less certain in the tropics. While the evidence from the past is clear on these points, it is not abundant worldwide. Forming a complete picture of the past is elusive in many tropical regions, even those as prominent as the Amazon, and future climate change may lack past analogs. Our ability to understand the future based on our understanding of what has happened so far in tropical forests therefore faces serious limitations.

L. Hannah, R. A. Betts, H. H. Shugart

16. Conservation, climate change, and tropical forests

Abstract

L. Hannah, T. Lovejoy

Backmatter

Titel: Tropical Rainforest Responses to Climatic Change
herausgegeben von: Mark Bush
John Flenley
William Gosling
Verlag: Springer Berlin Heidelberg
Electronic ISBN: 978-3-642-05383-2
Print ISBN: 978-3-642-05382-5
DOI: https://doi.org/10.1007/978-3-642-05383-2