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What controls the distribution of tropical forest and savanna?

journal contribution
posted on 2023-05-17, 15:30 authored by Murphy, BP, David BowmanDavid Bowman
Forest and savanna biomes dominate the tropics, yet factors controlling their distribution remain poorly understood. Climate is clearly important, but extensive savannas in some high rainfall areas suggest a decoupling of climate and vegetation. In some situations edaphic factors are important, with forest often associated with high nutrient availability. Fire also plays a key role in limiting forest, with fire exclusion often causing a switch from savanna to forest. These observations can be captured by a broad conceptual model with two components: (1) forest and savanna are alternative stable states, maintained by tree cover-fire feedbacks, (2) the interaction between tree growth rates and fire frequency limits forest development; any factor that increases growth (e.g. elevated availability of water, nutrients, CO2), or decreases fire frequency, will favour canopy closure. This model is consistent with the range of environmental variables correlated with forest distribution, and with the current trend of forest expansion, likely driven by increasing CO2 concentrations. Resolving the drivers of forest and savanna distribution has moved beyond simple correlative studies that are unlikely to establish ultimate causation. Experiments using Dynamic Global Vegetation Models, parameterised with measurements from each continent, provide an important tool for understanding the controls of these systems.

Funding

Australian Research Council

History

Publication title

Ecology Letters

Volume

15

Issue

7

Pagination

748-758

ISSN

1461-023X

Department/School

School of Natural Sciences

Publisher

Wiley-Blackwell Publishing Ltd

Place of publication

The Atrium, Chichester, West Sussex PO19 8SQ, UK

Rights statement

Copyright 2012 Blackwell Publishing Ltd/CNRS

Repository Status

  • Restricted

Socio-economic Objectives

Terrestrial biodiversity

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    University Of Tasmania

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