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THINKING beyond the canopy
Peat swamp forest degradation: A comparison between
the two peat-richest tropical countries Indonesia and
Peru
Hergoualc’h K, Gutierrez-Velez VH, Menton M, Verchot LV
10 October 2014 – IUFRO World Congress 2014 – Salt Lake City
THINKING beyond the canopy
Introduction
C stored in tropical peat soils 40%
total C stored in woody vegetation in
the entire Tropics
Indonesia & Peru: The 2 peat-richest
countries in the Tropics (Page et al., 2011)
Indonesian peat forests first
described 12 decades ago
/
Existence of peatlands in Peru
documented about 1 decade ago
THINKING beyond the canopy
Peatland threats
Indonesia: Extreme degradation and
deforestation for agricultural
expansion. Fires a major concern (Gaveau
et al., 2014)
/
Peru: Increasing pressure from
logging and deforestation for gold
mining
Peat forest degradation poorly
addressed in both countries
THINKING beyond the canopy
Peru: Land covers on peat and threat
Variety of land covers in Peruvian
peatlands
Research focused on M. flexuosa palm
dominated peat forest locally known
as ‘dense aguajal’
Major threat: Over-harvesting of M.
flexuosa palm by slashing it.
Purpose: palm fruit and larva (suri)
collection
THINKING beyond the canopy
Objectives
State of the art on Indonesian and
Peruvian peatlands’ extent, properties,
C stocks and degradation level
Evaluate potential of satellite data to:
- Distinguish M. flexuosa palm
dominated peat forest (‘dense
aguajal’) from other land covers
- Assess degradation level of ‘dense
aguajales’
THINKING beyond the canopy
Case study
Peruvian Amazon, Loreto, Pastaza-
Marañon basin, watersheds Marañon
& Ucayali rivers. Wide pressure
gradient in ‘dense aguajales’
´10
km
Vegetation
- Terra-firme forest (non-flooded)
- Restinga forest (periodically flooded, alluvial soils, dominated by
woody tree species)
- ‘Mixed aguajal’ (seasonally flooded, upland valley, with but not
dominated by M. flexuosa),
- ‘Dense aguajal’ (permanently flooded, depressions, M. flexuosa-
dominated swamp forests)
THINKING beyond the canopy
Degradation: 3 levels
Low: Undisturbed ‘dense aguajal’, clear dominance of
M. flexuosa palms, absence of stumps or other signs
of tree-cutting
Moderate: Structural characteristics of an undisturbed
‘dense aguajal’, presence of some stumps, cut trees
or other degradation evidence
High: ‘Dense aguajal’dominated by woody-tree
species rather than M. flexuosa palms as a
consequence of degradation, presence of stumps, cut
trees or other degradation evidence
THINKING beyond the canopy
Field data collection
Biomass inventory
Land cover Qty Purpose
Mixed aguajal 14 Groundtruthing land cover map
Dense aguajal
Groundtruthing land cover map &
Biomass inventory
Low degradation 2
Medium degradation 2
High degradation 4
50x50 m plots divided in
Four 25x25 m subplots: trees w/ DBH
> 10 cm; palms w/ H > 3 m
Four 10x10 m miniplots: trees 2.5 <
DBH < 10 cm; palms 1 < H < 3 m
Allometric models for calculating AGB
& BGB in woody trees, M. flexuosa,
M. aculeate, other palms
THINKING beyond the canopy
Satellite analysis
Landsat images fused with ALOS-PALSAR data
Database w/ structural data associated w/ each polygon & plot
linked to their geographic information
Terra-firme & restinga forests differentiated visually using a
false composite w/ Landsat bands 4, 5, 7 (non flooded/flooded)
Groundtruthing to differentiate between ‘dense/mixed aguajal’
Random forest algorithm to map ‘dense aguajal’ under
different levels of degradation and other LC
2 separate ‘mixed aguajal’ classes (2 very distinct groups in
the spectral space)
Quantitative separability analysis using Jeffries-Matusita index
THINKING beyond the canopy
Peatlands of Indonesia and PeruIndonesia Peru
Extent (km2) 150,000 50,000
Indonesia Peru
Extent (km2) 150,000 50,000
Location
(% of above
extent)
Sumatra (43%),
Kalimantan (32%),
Papua (25%)
Pastaza-Marañón basin (Loreto, San Martin,
Amazonas) (88%), Madre de Dios (1%)
Coastal & inland Inland
Indonesia Peru
Extent (km2) 150,000 50,000
Location
(% of above
extent)
Sumatra (43%),
Kalimantan (32%),
Papua (25%)
Pastaza-Marañón basin (Loreto, San Martin,
Amazonas) (88%), Madre de Dios (1%)
Coastal & inland Inland
Ecosystem type Variety of swamp
forests dominated by
woody trees
Herbaceous plant-dominated ecosystems
Mixed swamp forests,
Palm-dominated swamp forests (‘aguajal’)
- ‘Dense aguajal’ dominated by M.
flexuosa, permanently flooded
- ‘Mixed aguajal’ dominated by several
palm species, seasonally flooded
Not all ‘mixed aguajales’ grow on peat
THINKING beyond the canopy
Peatlands of Indonesia and Peru
Indonesia Peru
Nutrient regime Ombrotrophic mostly Ombrotrophic & minerotrophic
Indonesia Peru
Nutrient regime Ombrotrophic mostly Ombrotrophic & minerotrophic
C stocks
Peat C pool (Gt)
Peat C density
(mg C cm-3)
Vegetation
(Mg C ha-1)
57
64
220 peat swamp forest
4
35 ombrotrophic/26 minerotrophic
115 dense aguajal/88 mixed aguajal
Indonesia Peru
Nutrient regime Ombrotrophic mostly Ombrotrophic & minerotrophic
C stocks
Peat C pool (Gt)
Peat C density
(mg C cm-3)
Vegetation
(Mg C ha-1)
57
64
220 peat swamp forest
4
35 ombrotrophic/26 minerotrophic
115 dense aguajal/88 mixed aguajal
Degradation Logging & drainage
Initial AGB C stock reduced
by 53%
Peat emissions 22 Mg CO2eq.
ha−1 y−1
Logging
NO DATA
NO DATA
THINKING beyond the canopy
Case study Mapping of ‘dense aguajales’
degradation and
impact on biomass C stocks
THINKING beyond the canopy
Stand structural variables
0
300
600
900
1200
Low Medium High
# total trees/ha
0
300
600
900
1200
Low Medium High
# Woody trees/ha
0
200
400
600
Low Medium High
# M. flexuosa
palms/ha
No significant effect of degradation on the size of trees (DBH
woody trees or H of palms)
Biomass reduced considerably with
degradation
0
50
100
150
Low Medium High
Tree biomass (Mg C/ha)
THINKING beyond the canopy
Land covers and degradation of ‘dense aguajales’
Most of degradation in the
North (Tigre river).
Low degradation inside
Pacaya-Samiria reserve
‘Dense aguajales’ with low
degradation had a very
distinctive signature
Main confusion between LC:
‘Mixed aguajal’ overlapping with
spectral signature of ‘dense
aguajal’ with medium and high
degradation
THINKING beyond the canopy
Lowland peatlands Indonesia Peru: Knowledge gaps
Indonesia
Body of knowledge considerably improved over the past
decade
Forest degradation dynamics and related trace gas
emissions need much more attention
Peru
Huge knowledge gap: map, land cover description &
peat properties characterization, trace gas exchanges,
current and future extent of degradation
Particularly relevant for REDD+ implementation these
C-rich ecosystems
THINKING beyond the canopy
Approach to map peat dense aguajales & their
degradation in the Peruvian Amazon
Suitable to map non/slightly degraded dense aguajales
as the discrimination from other LC high reliable
Potential for degradation temporal monitoring in
non/slightly degraded dense aguajales using a reference
year
Discrimination highly & moderately degraded dense
aguajales & other LC: Moderate, confusion w/ mixed
aguajales. Improvement feasible w/ more field data
THINKING beyond the canopy
Approach to map peat dense aguajales & their
degradation in the Peruvian Amazon
Caveats:
- Low sampling intensity,
- Limited knowledge on the land use history in the
degraded areas
Further steps:
- Ground measurements to capture variables explaining
differences in the 2 groups of mixed aguajales
- Evaluation extent to which biomass changes relates to
peat C dynamics
- Application to a larger area and characterization of
additional peat LC
THINKING beyond the canopy
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