Tropical Biomes in Transition
Lead Research Organisation:
University of Leeds
Department Name: Sch of Geography
Abstract
Rainforest and savanna constitute the dominant two biomes of the tropical zone. They account for over 70% of the world's plant species. With massive areas and with high rates of latent and sensible heat exchange, rain forest and savanna also exert large, yet different, effects on the global climate. We have a limited understanding of their contemporary and future responses to global change. Tropical rainforests are a major terrestrial carbon store and are currently estimated to account for around half of the global terrestrial carbon sink. Although rainfall is a key determinant affecting their relative distributions, other factors such as soil conditions, fire and disturbances such as grazing and human influence are also involved. Our knowledge of these factors and how they interact in influencing vegetation type is still poor - all global vegetation models currently misspecify the distributions of these biomes. Such knowledge is fundamental for understanding and predicting transitions in tropical vegetation at local, regional and global scales. A drying of the Amazon Basin in coming decades could lead to the irreplaceable replacement of tropical forest with savanna, this then feeding back on the climate system as a consequence of changes in surface energy and mass balances - thereby accelerating global warming and tropical drying. Significant transitions centered around the gain or loss of savanna vegetation are not restricted to South America Improved predictions of the factors causing a transition from forest to savanna are fundamental to understanding this, and will depend on a significantly improved understanding of the environmental and edaphic determinants of the distribution of tropical vegetation at a global scale. Our main objective is to thus obtain a new knowledge of the underlying physiological basis of these determinants, to better understand the basis of differences in surface energy and CO2 exchange differences between forest and savanna, and to integrate this information for a much more accurate representation of these processes in global vegetation models than is currently possible. This will be achieved by a 'model-data development program involving field campaigns with local collaborators to examine climate/soil/disturbance associations in key 'hot spot' rainforest/savanna transition zones. Comprehensive measurements will be made including key plant physiological processes (photosynthesis water relations), vegetation stand structure and composition, and soil physical and chemical properties. New high resolution climatologies will also be developed and novel methodologies advanced to allow determination of tropical vegetation structure and fire frequency from space. These will be validated and tested and along with the field based data and then used to develop a new quantitative understanding of tropical biome distributions at a global scale. Derived relationships will be compared against more primitive ones currently used to describe tropical vegetation/climate relationships and consequences for predictions of past and future vegetation change evaluated Information from field observations will be used in conjunction with data assimilated from outside the project to develop new models of tropical vegetation distribution and function. Models derived will be as mechanistic as possible with predicted distributions and structure/flux of vegetation tested using larger scale distributional and structural data from remote sensing data Finally we will incorporate our new and improved understanding of tropical vegetation distribution and processes with new global climate model (GCM) runs to provide new insights into impending tropical vegetation change, associated climatic feedbacks and the future global climate. We anticipate this will lead to a fundamental improvement in our ability to predict the global climate of the 21st century.
Publications

Bloomfield K
(2014)
Contrasting photosynthetic characteristics of forest vs. savanna species (Far North Queensland, Australia)
in Biogeosciences

Brienen RJ
(2015)
Long-term decline of the Amazon carbon sink.
in Nature

De Oliveira E
(2013)
Diversity, abundance and distribution of lianas of the Cerrado-Amazonian forest transition, Brazil
in Plant Ecology & Diversity


Domingues TF
(2010)
Co-limitation of photosynthetic capacity by nitrogen and phosphorus in West Africa woodlands.
in Plant, cell & environment

Fauset S
(2015)
Hyperdominance in Amazonian forest carbon cycling.
in Nature communications

Feldpausch T
(2011)
Height-diameter allometry of tropical forest trees
in Biogeosciences

Feldpausch T
(2016)
Amazon forest response to repeated droughts AMAZON FOREST RESPONSE TO DROUGHTS
in Global Biogeochemical Cycles

Gatti LV
(2014)
Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements.
in Nature

Honorio Coronado E
(2015)
Phylogenetic diversity of Amazonian tree communities
in Diversity and Distributions

Johnson MO
(2016)
Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models.
in Global change biology

KATTGE J
(2011)
TRY - a global database of plant traits TRY - A GLOBAL DATABASE OF PLANT TRAITS
in Global Change Biology

Lewis SL
(2009)
Increasing carbon storage in intact African tropical forests.
in Nature

Lloyd J
(2008)
Contributions of woody and herbaceous vegetation to tropical savanna ecosystem productivity: a quasi-global estimate.
in Tree physiology


Lloyd J
(2009)
Are the dynamics of tropical forests dominated by large and rare disturbance events?
in Ecology letters

Lloyd J
(2009)
Amazonia and Global Change


Lloyd J
(2008)
Effects of rising temperatures and [CO2] on the physiology of tropical forest trees.
in Philosophical transactions of the Royal Society of London. Series B, Biological sciences

Lloyd J
(2016)
Are fire mediated feedbacks burning out of control?
in Biogeosciences Discussions


Marimon B
(2013)
Disequilibrium and hyperdynamic tree turnover at the forest-cerrado transition zone in southern Amazonia
in Plant Ecology & Diversity

Massi K
(2017)
Does soil pyrogenic carbon determine plant functional traits in Amazon Basin forests?
in Plant Ecology

Mitchard ET
(2014)
Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites.
in Global ecology and biogeography : a journal of macroecology

Nardoto G
(2013)
Basin-wide variations in Amazon forest nitrogen-cycling characteristics as inferred from plant and soil 15 N: 14 N measurements
in Plant Ecology & Diversity
Description | Tropical vegetation types require delineation in terms of both florstics and stand structure. The newest simulation suggest that tropical forests are less sensitive to climate change than previously thought, but with our lack of understanding in temperature responses of photosynthesis and respiration remaining key uncertainties. |
Sectors | Environment |
Description | FAPESP/NERC Biomes |
Amount | R$ 2,576,234 (BRL) |
Funding ID | 2015/50488-5 |
Organisation | São Paulo Research Foundation (FAPESP) |
Sector | Public |
Country | Brazil |
Start | 09/2016 |
End | 09/2019 |