Variation of forest structure and composition with

Report
Variation of forest ecosystems with elevation:
insights from a 3500 m elevation gradient in
the Andes
The Andes Biodiversity and Ecosystems Research Group (ABERG)
Y. Malhi, M. Silman, P. Meir, K. Feeley, N. Salinas, S. Saatchi, M. Bird
L. Aragao, C. Girardin, J. Fisher, T. Marthews, D. Metcalfe, J. Espejo, W. Farfan,
K. Garcia, A. Nottingham, J. Whittaker, M. Zimmerman, K. Feeley, J. Rapp. J.
Lloyd, R. Guerreri, O. Atkin and many more
University of Oxford UK,
Wake Forest University USA,
University of Edinburgh UK,
Univesidad San Antonio Abad ,Cuzco, Peru
Pontoficia Universidad de Lima, Peru
Jet Propulsion Laboratory, NASA
[email protected]
www.yadvindermalhi.org
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
Kosñipata Valley and adjoining Amazon lowlands
Andes Biodiversity and Ecosystem Research Group:
www.aberg.org
200m
2000m
1250m
1000m
1750m
1500m
2250m
2500m
2750m
3450m
3250m
3000m
26.4oC
15.3oC
21oC
22.1oC
16.7oC
19oC
14.8oC
13.3oC
11.9oC
8.5oC
9.2oC
10.5oC
Malhi, Y. et al (2010) Elevation gradients in the tropics: laboratories for ecosystem ecology and
global change research, Global Change Biology, 16, 12, 3171-3175
Malhi, Y. et al (2010) Elevation gradients in the tropics: laboratories for ecosystem ecology and
global change research, Global Change Biology, 16, 12, 3171-3175
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
Temperature and rainfall gradients
Precipitation (mm yr-1)
8000
30
Precipitation (mm yr-1)
7000
25
6000
20
5000
4000
15
3000
10
2000
5
Mean Annual Temperature (deg C)
Mean Annual Temperature(deg C)
1000
0
0
0
>60 ha
1000
2000
Elevation (m)
3000
4000
1 ha plots
Trees 10cm dbh
Tree Species Diversity
Lowland levels of diversity
maintained to ~1700 m
**
Most species have narrow elevation ranges
Tree species ranking
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
gem.tropicalforests.ox.ac.uk
Measuring Tropical Forest Carbon Allocation and Cycling: A RAINFOR-GEM Field Manual for
Intensive Census Plots (v2.2). Manual, Global Ecosystems Monitoring network,
GPP= 36.15±3.97
The carbon
cycle of a
forest at
Tambopata.
Peru
NPPTotal = 15.14±0.83
NPPAG = 9.96±0.41
NPPBG = 5.18±0.72
NPP litterfall = 5.61±0.32
NPP herbivory = 0.76±0.05
R leaf =8.86±2.78
NPP branch turnover = 0.95±0.10
D fine litterfall
R stem = 5.85±2.50
NPP ACW= 2.64±0.24
R soil =12.98±0.82
R cwd
5.61±0.32
D CWD 3.59±0.26
R coarseroot
1.23±0.62
R rhizosphere
5.07±0.86
NPP coarse roots = 0.51±0.05
NPP fine roots = 4.67±0.72
D root
5.18±0.72
R soilhet = 7.14±0.49
Malhi et al, Plant Ecology and Diversity, 2014
No. of tree species
GPP and NPP decline with elevation
but the transition is abrupt at
100around 16-1700 m asl
(dry season cloud base)
0.60
0.55
0.50
(E)
400
35
300
(B)
14
(F)
150012
10
1000
8
30
200
25
100
500 6
20
0
0
density (g cm-3 ha-1)
Epiphyte biomass-1(g m-2-1)
NPP (Mg C ha year )
(A)
40
0.70
50
16
1000
2000
Elevation (m)
3000
4
4000
(C)
0
tree species (ha-1)
No. of tree ferns -1
(ha-1)
GPP (Mg C ha year-1)
Wood density (g cm
0.65
1000
2000
3000
Elevation (m)
150plots along an elevation transect in the
Fig. 1. Ecosystem characteristics in 1 ha forest dynamics
0.65
Peruvian Andes. Solid lines indicate linear fits above/below cloud forest transition (dashed line).
0.60
100
4000
(D)
LAI
0
Max photosynthesis
under high light
0
25
12
Leaf Area Index
2.08
10
P (LAI
g m-2)
Asat (umol m
-2
N (g m
m-2 )sec-1)
Asat (umol
6
4 leaf area index do
Canopy
photosynthetic capacity and
4 not show a strong decline or abrupt transition with
2
elevation
2
208
6
154
1.56
1.04
0.52
2
100
25 0
0.00
1000 2000 3000 4000
2.0
Elevation (m)
0
1000 2000 3000 4000
Elevation (m)
g m-2)
g m-2)
1.5
Fig.cloud
2.
characteristics
1 ha
forest dynamics
plotsmay
alonghave
an elevation
transect
20Leaf-level
Once
immersion
is factoredinout,
autotrophic
processes
little dependence
temperature
in the Peruvian Andes. Dashed on
linemean
indicates
cloud1.0
forest transition.
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
Exploring heterotrophic processes
26.4oC
15.3oC
21oC
22.1oC
16.7oC
19oC
14.8oC
13.3oC
11.9oC
8.5oC
9.2oC
10.5oC
Translocation of root-free soil
Zimmermann et al. (2010)
Large-scale leaf and wood
translocation experiment
Salinas et al. (2011) New Phytologist
Translocation experiments along the elevation gradient
Leaf litter
4725 litter bags
Q10 = 3.06±0.28
(r2 = 0.97, p = 0.002)
Salinas et al.,
New Phytologist, 2011
2.5
Salinas et al.
In review.
2
k (x 10-3 d-1)
Fine wood litter
1575 litter bags
Q10 = 4.0±0.56
(r2 = 0.95, p = 0.004)
1.5
1
0.5
0
10
12
14
16
18
20
Annual mean soil temp. (°C)
22
24
26
The sensitivity of heterotrophic decomposition is so high because
soil microbial and macrofaunal communities completely change at
warmer temperatures
Microbial biomass increases with elevation
Increased dominance of fungi relative to
bacteria at high elevation
Termites are only abundant in the lowlands
Palin et al. (2011) Biotropica
Whittaker et al. (2014) Journal of Ecology
Palin et al. (2001) Biotropica
Implications under warming
Autotrophic processes may be very insensitive to
temperature (within the range observed) because
of acclimation and community turnover
Heterotrophic processes may be very sensitive to
temperature because of community turnover
Hence warming would be expected to increase loss
of carbon from soil more than it increases gain of
carbon in tree biomass
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
Niches from collection data
MIGRATION RATE (m yr-1)
10
8
6
4
2
0
-2
PLOT
The mean plant community in most plots has been increasing over
last 10 years by 2.0m yr-1 (+0.5 – +3.5m yr-1).
Feeley et al. 2011 JBioGeo
Perú:
MIGRATION RATE (m yr-1)
10
8
Required migration rate for climate
equilibrium
10
8
6
6
4
4
2
2
0
0
-2
-2
+2.0m yr-1 (+0.6 – +3.6m yr-1)
Costa Rica:
+2.0m yr-1 (+0.5 – +3.5m yr-1).
Feeley, et al. 2013, Global Change Biology
Talk structure
Study region
Plant diversity and distributions
Ecosystem productivity
Heterotrophic processes
Plant distribution change
Tree line studies
So tree species are shifting upslope.
Is the forest biome also shifting?
1963
2005
1963
2005
1963 US Air
Force
Recon aerial
photography
1963
IKONOS
satellite
imagery
2005
Results: Andean timberline migration
• Across study area, ~80% of timberline did not change
• Upslope migration more likely in protected areas
• Upslope migration rates decreased with increasing elevation
• Overall migration rates far slower than required to maintain
equilibrium with climate change
Status
Annualized migration Years to 2100 climate
rate (m y-1)
equilibrium (+5⁰C)
Timberline
Timberline
Protected
0.24
3,750
Unprotected
0.05
18,000
The Grass Ceiling?
Ecotone migration rates are 12 to 110
times slower than the observed species
migration rates in our valley
Protected areas help, but management
may be needed interventions are needed
to assist migration
Large changes in composition with elevation
600
TO_1000
DCA Axis 2
500
PA_600
TO_800
400
300
TU_1800
CA_1250
WA_3000
SP_1750 TU_2000
TU_2750
TU_2250
TU_3000
TU_3450 AC_3565 AK_3625
SP_1500
PA_425
TU_2500
TU_3250
CA_1500
200
100
SI_1500
SI_1250
0
0
500
1000
DCA Axis 1
1500
2000
Composition and Elevation
(1 ha plots)
1400
1200
DCA Axis 1
1000
800
600
400
200
0
-200
-400
-600
-800
0
1000
2000
Elevation (m)
3000
4000

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