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

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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

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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

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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’

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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)

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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

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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

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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

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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

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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

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Case study Mapping of ‘dense aguajales’

degradation and

impact on biomass C stocks

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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)

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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

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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

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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

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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

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