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1
Recent Change in Mature Amazonian Forests, 1980-
2005.
Amazon Conference, Oxford, 21st March 2007
Oliver Phillips, University of Leeds
Mount Kinabalu4100 m
2
Fredy Ramirez, Iquitos, Peru
Thanks to these RAINFOR investigators & collaboratorsT. Baker, J. Lloyd, Y. Malhi, J. Peacock, G. Lopez Gonzalez, C. Czimczik2 , L. Arroyo3,4, N.
Higuchi5, T. Killeen3,6, W. F. Laurance7,8, S. L. Lewis1,9, A. Monteagudo10,11, F. Ramirez, D. Neill4, P. Núñez Vargas10, N. Silva12,13, J. Terborgh14, R. Vásquez
Martínez11, M. Alexiades15, S. Almeida16, S. Brown17, J. Chave18, J. A. Comiskey19, A. Di Fiore20, T. Erwin19, E. Jimenez, C. Kuebler6, S. G. Laurance7,8, H. E. M.
Nascimento7,8, J. Olivier18, W. Palacios21, S. Patiño2, 22, N. Pitman15, A. Prieto, C. A. Quesada23,2, M. Saldias3, A. Torres Lezama24, B. Vinceti25, E. Alvarez26, A. Rudas-
Ll27
1. University of Leeds, UK. 2. Max-Planck-Institut für Biogeochemie, Jena, Germany. 3. Museo Noel Kempff Mercado, Santa Cruz, Bolivia. 4. Missouri Botanical Garden, St. Louis MO, USA. 5. Instituto National de Pesquisas Amazônicas, Manaus, Brazil. 6. Center for Applied Biodiversity Science, Conservation International, Washington DC, USA. 7. Smithsonian Tropical Research Institute, Panama. 8. Biological Dynamics of Forest Fragments Program, Manaus, Brazil. 9. School of Geosciences, University of Edinburgh, UK. 10. Herbario Vargas, Universidad Nacional San Antonio Abad del Cusco, Peru. 11. Proyecto Flora del Perú, Jardin Botanico de Missouri, Oxapampa, Perú. 12. CIFOR, Tapajos, Brazil. 13. EMBRAPA Amazonia Oriental, Belém, Brazil. 14. Center for Tropical Conservation, Duke University, Durham NC, USA. 15. New York Botanical Garden, Bronx NY, USA. 16. Museu Paraense Emilio Goeldi, Belem, Brazil. 17. Winrock International, Arlington VA, USA. 18. Laboratoire Evolution et Diversité Biologique, CNRS/UPS Toulouse, France. 19. Smithsonian Institution, Washington DC, USA. 20. Department of Anthropology, New York University NY, USA. 21. Fundacion Jatun Sacha, Quito, Ecuador. 22. Alexander von Humboldt Biological Research Institute, Bogotá, Colombia. 23. Departamento de Ecología, Universidade de Brasilia, Brazil. 24. INDEFOR, Universidad de Los Andes, Mérida, Venezuela. 25. International Plant Genetic Resources Instit te Rome Ital 26 Eq ipo de Gestión Ambiental Intercone ión Eléctrica S A ISA
3
Outline
Amazon Conference, Oxford, 21st March 2007
1.RAINFOR objectives and plot methodology
2.On-the-ground evidence for recent changes in Amazon forests
3.Some future prospects
Main objectives of RAINFOR
1. Understand how and why they vary in space
2. Understand how and why they change through time
Use permanent plots to research the biomass, tree dynamics, production, biodiversity of Amazonian forests
to…
4
NOEL KEMPFF 2001,6,7TAMBOPATA 2002,3,6
Bogi 2002,7
IQUITOS 2001,5,6MANAUS
2002,5CAXIUANA
2002,4,5,6
BRAGANCA2002
TAPAJOS 2003Jatun Sacha 2002,7
RAINFOR Field Activities 2001-2007, permanent plots
ACRE2003 SINOP 2002
SAN CARLOS2004,6
JARI 2003
MOCAMBO2003
EL DORADO2004
Andes Transect 2003,6
RIO GRANDE2004
AMACAYACU2004,5,6,7
Alta Floresta 2002
Cusco Amazonico2003,6
ZAFIRE2005,6
Mabura Hills2006
Jenaro Herrera 2005,6,7
Dois Irmaos2003,6
Tiputini 2002,7
Sacta 2006BEEM 2006
Porongaba2003,6
Combine the “botanical approach”… (floristic data), with…
Allpahuayo, Peru
5
… the “forestry approach”… (biomass and growth), with…
Caxiuana, Brasil
Sucusari, Peru
… the “ecophysiological approach”… standardized dataset of soils and leaves nutrient status
6
DRY SEASON
+
-
+
-SOIL FERTILITY
RAINFOR Sampling Strategy
Some Results
Recent changes in the structure and dynamics
of tropical forests
7
Rate of change in biomass for 59 plots Mg DW ha-1 a-1
Baker et al. (2004), Phil. Trans Roy. Soc, 359, 353-365.
C source C sinkChanges in the biomass of old growth Amazonian forest plots
1 Pg = 1 billion metric tonnes
0.61 ± 0.21 Mg C ha-1 a-1
Scaled up to basin-level (6 m km2) the biomass sink (0.3-0.6 Pg C a-1),
is equivalent to emissions from Amazonian deforestation (0.2–0.4 Pg C a-1)
So…
• ON AVERAGE, stocks of biomass and stems have increased
• What is the proximal mechanism?
i.e., is it increasing growth or decreasing mortality?
8
1
1.5
2
2.5
3
1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000
Year
Ann
ual r
ate
of s
tem
mor
talit
y or
recr
uitm
ent,
%Recruitment meanRecruitment mean-CIRecruitment mean+CIMortality meanMortality mean-CIMortality mean+CI
Phillips et al, 2004. Phil. Trans. Roy. Society
Tree recruitment and mortality, South American plots
Changes within 50 Amazon plots with 3 censuses
Stand BA growth
Stand BA mortality
Stem recruitment
Stem mortality
Annu
al ra
te, %
0.0
0.5
1.0
1.5
2.0
2.5 Interval 1 Interval 2
Relative increase ~2 to 4 % a-1
P<0.001 P<0.05 P<0.001 P<0.01
Lewis et al. 2004 Phil Trans Roy. Soc. London
9
Stand BA growth
Stand BA mortality
Stem recruitmentStem mortality
Ann
ual r
ate,
%
0.0
0.5
1.0
1.5
2.0
2.5
3.0Interval 1 Interval 2
Stand BA growth
Stand BA mortalityStem recruitment
Stem mortality
Ann
ual r
ate,
%
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Eastern & Central Amazonian Forests (SLOW FORESTS)
Western Amazonian Forests (FAST FORESTS)
Lewis et al. 2004 Phil. Trans. Roy. Soc.
Western Amazonia Central & Eastern Amazonia
10
Increase in biomass ca. 1980-2003, apparently at a rate related to soil fertility
00.20.40.60.8
11.21.41.61.8
2
Old ox
isols
Spodo
sol/p
sammen
t
Ultisols
Young
er ox
isols
Crystal
line s
hield
Holoce
ne al
luvium
Older a
lluviu
m
incep
tisols
/andis
ols
Bio
mas
s ca
rbon
incr
emen
t (t
C/h
a/yr
)n = 95
Increasing fertility
unpublished RAINFOR data
Annual relative BA change, %-2 -1 0 1 2 3A
nnua
l rel
ativ
e st
em tu
rnov
er c
hang
e, %
-10
-5
0
5
10
15
20
25
30
30
1
8
11
Concerted changes in forest structure and dynamics
unpublished RAINFOR data
bigger
faster
11
Tasa de reemplazo, arboles pantropicales
paleotropicos (azul); neotropicos (rojo). prom edio y intervales de confianza
0.5
1
1.5
2
2.5
3
1950 1960 1970 1980 1990 2000Year
Ann
ual t
ree
turn
over
, %
unpublished data, updated from Phillips and Gentry 1994
So, the dominant mechanism(s) must …
1. Boost growth first, rather than mortality
2. Be very large scale (possibly global, certainly continental)
3. Have greatest absolute impact on fluxes in nutrient-rich, productive forests
12
The simplest explanation is that an externaldriver is accelerating forest growth, which in turn is
accelerating tree death.BUT, the difference between the two is rather small
Net C sink
Accelerated treegrowth and recruitment
Acceleratedtree death (lagging growth)
Mortality mean in 2000 = 1.6% a-1
Growth mean in 2000 = 1.9% a-1
Outline
Amazon Conference, Oxford, 21st March 2007
1.RAINFOR objectives and plot methodology
2.On-the-ground evidence for recent changes in Amazon forests
3.Some future prospects
13
How vulnerable is the mature forest biomass sink?
1. Drought will affect growth or mortality, possibly both
2. Increases in turnover rates (growth or mortality) will probably impact species composition
Currently, forests appear not to be at equilibrium, and are probably already responding to
atmospheric changes
1. Drought impacts?
14
Recensus 60 plots
• Bolivia, Brasil, Colombia, Guyana, Peru, Venezuela• Census interval captures 2005 drought and
immediate post-drought period• Evaluate impacts by comparison with long-term
trends… … analysis just begun
How vulnerable is the mature forest biomass sink? 2005 Amazonian drought
Plots recensused across Amazonia post-2005
drought
How vulnerable is the mature forest biomass sink?
Aragao et al. 2007
15
1. Plots gained biomass before 2005 (P<0.01)2. During drought period biomass change not different from zero (P=0.85)
Net
chan
ge, m
2 ba
sal a
rea
per
hect
are
per
year
drought period clusternon-drought period cluster
0.2
0.1
0.0
-0.1
-0.2
0
Interval Plot of non-drought period cluster, drought period cluster95% CI for the Mean
Preliminary ResultsHow vulnerable is the mature
forest biomass sink?
2. Increases in turnover could affect species composition
and biomass?
• Faster turnover = more rapid gap formation, conditions favoured for fast-growing, light-wooded species
• Potential for positive feedback on turnover rates• Currently Amazonia is extremely varied: there
are many different ways of being a forest, different functional composition, different biomass….
How vulnerable is the mature forest biomass sink?
16
Lots of functional diversity is available
in Amazonia!
Baker et al. (2004), Global Change Biology, 10, 545-562.
0
5
10
15
20
25
30
0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95 1.05
Midpoint of specific gravity class / g cm-3
% s
tem
s
NW Amazonia
C & E Amazonia
SW Amazonia
How vulnerable is the mature forest biomass sink?
2. Increases in turnover could affect species composition…
Stand-level mean wood density as a function of annual stem turnover; 127 lowland plots
across South America
y = 0.7075x-0.1605
R2 = 0.334
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0 1 2 3 4 5 6
Mean of mortality and recruitment, % a-1, census-interval corrected
Stan
d-le
vel w
ood
dens
ity, g
cm
-3
How vulnerable is the mature forest biomass sink?
17
2. Increases in turnover could affect species composition and therefore biomass
Biomass as a function of annual stem turnover rate; 127 lowland
plots across South America
y = 349.43x-0.1955
R2 = 0.198
100
200
300
400
500
0 1 2 3 4 5 6
Mean of mortality and recruitment, % a-1, census-interval corrected
Bio
mas
s, M
g ha
-1
How vulnerable is the mature forest biomass sink?
Biomass as a function of stem turnover; 229 lowland forest plots
across South America, Africa, Australia
y = 392.58x-0.3231
R2 = 0.356
100
200
300
400
500
600
700
800
0 1 2 3 4 5 6
Mean of mortality and recruitment, % a-1, census-interval corrected
Bio
mas
s, M
g ha
-1
2. Increases in turnover could affect species composition and therefore biomass across the tropics
18
Compositional change already: Large liana density is increasing across Western Amazonia
2
6
10
14
18
1981 1986 1991 1996 2001
Lian
a st
ems
per h
aN.Peru S.Peru Bolivia Ecuadormean+CI mean-CI mean
Phillips et al. 2002
• Amazonia old-growth has provided a biomass C sink of 0.3-0.6 Pg C a-1, for at least two decades
Conclusions. Permanent Plots indicate:
• Wood production and mortality have increased – there appears already to be a signal of atmospheric change
• Anticipated changes in composition put this at risk, even before considering climate change and land-use change
19