LBA ECO Synthesis Activities

Summary of Current Activities

Michael Keller

NASA LBA-ECO Project Scientist

LBA-ECO Synthesis

• Review of LBA-ECO Questions– Signs of progress– Unfinished business

• Books for Synthesis

• Phase III Scientific Activities

• Summary and Conclusions

Review of LBA-ECO Questions

• LC–Q1 What are the rates and mechanisms of forest conversion to agricultural land uses, and what is the relative importance of these land uses?

• LC–Q2 At what rate are converted lands abandoned to secondary forests; what is the fate of these converted lands, and what are the overall dynamic patterns of land conversion and abandonment?

• LC–Q3 What is the area of forest that is affected by selective logging each year? How does the intensity of selective logging influence forest ecosystem function, thus altering forest regrowth and flammability?

• LC–Q4 What are plausible scenarios for future land–cover change in Amazonia?

2000

1999

Asner et al., Ecol. Apps. (2004)

MC Unmixing with Landsat 7 ETM+ Imagery

Review of LBA-ECO Questions

• CD–Q1 What is the (climatically driven) seasonal and interannual variability of the CO2 flux between the atmosphere and different land cover/use types?

• CD–Q2 How do biological processes such as mortality and recruitment or succession following land use change influence the net annual C balance for different land–cover/land use types?

• CD–Q3 What are the relative contributions of fluxes from natural and disturbed ecosystems to the net Amazonia–wide flux? This question can be approached through a number of subsidiary questions:– Contribution from BARCA

Keller et al. 2004 Ecological Applications

Carbon Flux: Seasonality

Review of LBA-ECO Questions

• CD–Q3a How do pools and fluxes of C and nutrients (in soils) of pasture/cropland change over time and what factors determine C gain or loss?

• CD–Q3b How does selective logging change the storage and cycling of C in forests?

• CD–Q3c What factors (biologically mediated, land–use history, soil properties, etc.) control the rate of C sequestration in biomass and soils of re-growing forest?

• CD–Q3d What portion of the Amazonia–wide C flux is from fire? How do ecosystems recover from fire? What are the relations between land management and fire occurrence/frequency?

2000

Cont N P N+P

2002

Cont N P N+P

1999

Cont N P N+P

Bio

ma

ss

(M

g h

a-1

)

0

5

10

15

20

25

30

35

2001

Cont N P N+P

Tree Foliage

Trees > 2cm

Dead < 2 cm

Wood < 2 cm

Herb

Vine

Grass

fertilization

Davidson et al. Ecol. Appl. 2004

Progress: Secondary Re-Growth

Review of LBA-ECO Questions• ND–Q1 How do stocks, cycling rates and budgets of carbon and

important elements N, P, K, Ca, Mg, and Al change under different land covers and land uses?

• ND–Q2 Are nutrients major factors that control the rates of re–growth and carbon accumulation in abandoned pastures and re–growing secondary forests?

• ND-Q3. What are the processes and consequences of atmospheric horizontal transport of nutrients (wind) on the nutrient stocks and cycles of ecosystems within the Amazon basin at various spatial and temporal scales?

• E.g., • - Saharan dust inputs• - Losses and redistribution due to fire• - Links between physical climate models and nutrient cycling?

Progress: Nutrient Accumulations

C:N C:P x 0.1 C:K C:Ca C:Mg x 0.1

Car

bon:

Nut

rient

Rat

io

0

100

200

300

400

Mature19 year14 year8 year

Keller et al. Ecological Applications 2004

Review of LBA-ECO Questions• ND-Q4. How do changes in land-use and climate alter the

stocks, processes and fluxes of dissolved and particulate organic matter, nutrients, and trace gases from the uplands across the riparian zones and floodplains and down the channels of river corridors?

• ‑ How will the composition and quantity of nutrients and organic matter entering and being processed within streams be altered under different land-use change scenarios?

• ‑ Are there unique signatures that can be traced downstream?• ‑ To what extent do intact riparian zones buffer streams against

changes due to anthroprogenic activities in surrounding uplands?

• ND-Q5. What is the importance of periodically “wet” environments (from moist soils to standing and flowing waters) for the land and atmospheric balances of nutrients, CO2, trace gases, and water and energy on multiple scales?

Progress: Methane Emission from the Amazon Basin

Final estimates suggest that the Amazon Basin wetlands may produce as much as 20% of the natural global source of methane. This estimate provides the first rigorous analysis of errors from both area estimates, flux estimates, and inter-annual variability. (Melack et al. Global Change Biology, 10: 530-544, 2004)

Mainstem Emissions

Interannual Variability

Lowland Amazon Basin (<500 m asl)(5.19 million km2)

Methane Emission 22 Tg C y-1

 

Central Amazon Basin(1.77 million km2)

Methane Emission 6.8 + 1.3 Tg C y-1

Low

Mid

High

Review of LBA-ECO Questions

• TG‑Q1. How are fluxes of trace gases and aerosols between ecosystems (both upland & wetland) and the atmosphere of Amazonia affected by land cover and land use change?

• TG‑Q2. What is the (climatically driven) seasonal and inter‑annual variability of trace gas and aerosol fluxes between the atmosphere and different land use/land cover types?

• TG‑Q3. Are losses and gains of carbon from Amazonian ecosystems in forms other than CO2 (e.g. CO, CH4, VOC, organic aerosol) of sufficient magnitude to influence ecosystem carbon balance?

Books for Synthesis: An Activity of LBA-ECO

• Why books?– Editorial control of content– Format and content more flexible than journal articles– Induce synthetic work that would not occur otherwise

• We are holding discussions with Island Press, publisher of the SCOPE volumes– Not for profit– Willing to provide layouts for volumes to be used for

translation

Current Book Themes Under Development

• Agriculture and Pastoral Systems: Biogeochemistry

• Secondary Forests: Distribution and Productivity

• Fire in the Amazon: Human Interactions, Biogeochemical and Atmospheric Effects

Future Book Themes

• Stream and Rivers Chemistry: Land Use Change Effects

• Forest Dynamics and Logging

• Amazon Region Carbon Dynamics (post- BARCA)

• Suggestions?

• IGBP Book Series

Reflections (1)

• Should we develop plausible scenarios for the future of Amazonia? These would be critical for modeling exercises considering future conditions.

• Extension of the network of forest plots can have considerable long term value. Excellent opportunities exist to link these to remote sensing data for regional studies of forest dynamics.

• Regional studies of atmospheric composition should be fostered beyond BARCA and expanded.

Reflections (2)

• Continue and fortify the studies of smoke effects with a strengthening of the linkages between the atmospheric studies, ecological studies, and studies of social and economic controls on fire use.

• Take advantage of the strength of LBA in understanding of atmospheric transport to consider the role of atmospheric redistribution of nutrients.

• Collect and unify existing data to give a detailed regional picture of soil nutrients.

Reflections (3)

• Build on existing studies of river chemistry with increased attention to the riparian zone and continued attention to the tracers of downstream effects of land use change. How far can we go from the source?

• We are just getting hints of the role of the ecosystems in controlling atmospheric composition. What can we do to extend the point studies to the region?

What does the future hold for LBA?

A Good Future?