1. Daniel Metcalfe and numerous others Oxford University Centre for the Environment daniel.metcalfe@ouce.ox.ac.uk Drought impacts on leaf morphology and respiration

2. ↑ atmospheric CO 2 levels↓ precipitation ↓ photosynthesis & ↑ soil respiration ↑ temperature ↑ terrestrial CO 2 production Future drought in the Amazon

3. Model uncertainty

4. Justification & Objectives  Possible future drought.  What are the drivers of short and longer-term forest carbon dioxide exchange  Neglected but important components of the forest carbon cycle 1)Characterize canopy characteristics over five years in an artificially droughted forest. 2)Get a first approximation of drought impacts on a key component of the ecosystem carbon cycle- leaf dark respiration

5. Dry season length + - Drought experiment 1)Matched Drought and Control plots 2)Panels exclude approx 50% rainfall 3)Perimeter trenching to minimize lateral water transport 2002 2003 2004 2005 2006 2007

6. P canopy P stem M leaf M stem

7. R stem R leaf R soil P root R cwd M root

8. Canopy morphology & density 2002 2003 2004 2005 2006 2007

9. Two contrasting ways of quantifying canopy density 2002 2003 2004 2005 2006 2007

10. Leaf dark respiration 2002 2003 2004 2005 2006 2007

11. Variation with canopy height 0-10m 11-20 m >21 m

12. Global trends in leaf respiration 0 100 200 300 400 Specific leaf area

13. Poorly quantified components of the ecosystem improving infrastructure and equipments, applying techniques from other disciplines Inferring long-term responses from short-term observations Increasing length of observations, improve mechanistic understanding of forest responses Multiple interactions Multivariate statistical analysis, increasing model complexity: requires more field data Spatial Heterogeneity Increasing measurement plots, intra-plot sample size Evidence accumulating for profound changes in the structure and function of the Amazon ecosystem What will be the human and environmental impacts of these changes?

14. Key websites - -The Amazon Forest Inventory Network: http://www.geog.leeds.ac.uk/projects/rainfor/ - -Project for the Advancement of Networked Science in Amazonia: http://www.eci.ox.ac.uk/projects/panamazonia/ http://www.eci.ox.ac.uk/projects/panamazonia/ - -Large Scale Atmosphere-Biosphere Experiment in Amazonia: http://www.lbaeco.org/lbaeco/ Daniel Metcalfe daniel.metalfe@ouce.ox.ac.uk