REFERENCES APFP (2009) Peatlands in Southeast Asia - A Profile. ASEAN Peatlands Forests Project. Rehabilitation and Sustainable Use of Peatland Forests in Southeast Asia. ASEAN Secretariat &GEC. Miettinen, J., Shi, C. & Liew, S.C. (2012) Two decades of destruction in Southeast Asia’s peat swamp forests. Frontiers in Ecology and the Environment, 10: 124–128. Page, S.E., Siegert, F., Rieley, J.O., Boehm, H.-D.V., Jaya, A. & Limin, S. (2002) The Amount of Carbon Released from Peat and Forest Fires in Indonesia During 1997. Nature, 420: 61–65. Page, S.E., Rieley, J.O. & Banks, C.J. (2011) Global and regional importance of the tropical peatland carbon pool. Global Change Biology, 17: 798–818. Phillips, V.D. (1998) Peatswamp ecology and sustainable development in Borneo. Biodiversity and Conservation, 7: 651–671. Posa, M.R.C., Wijedasa, L.S. & Corlett, R.T. (2011) Biodiversity and conservation of tropical peat swamp forests. BioScience, 61: 49–57. SarVision (2011) Impact of oil palm plantations on peatland conversion in Sarawak 2005-2010. Wetlands International.

ACKNOWLEDGEMENTS S. Jones, K. L. Khoon, B. Phalan & A. Massey provided assistance and advice. NERC, the NERC Radiocarbon Dating Facility (Radiocarbon Analysis Allocation Number 1565.0411) and SUERC Dating Laboratory provided financial support.

RESULTS CONCLUSIONS

①, ② & ③

• Peat swamp forest vegetation has dominated in each site since peat development started, showing fluctuations in pioneer & mature taxa that suggest the forest was responding dynamically to small disturbances

• Forest vegetation in these peat ecosystems has shown resilience to past disturbances, for example perturbations caused by local fires and climatic changes, such as ENSO events

• In the last c. 300 years, local & regional burning & increases in open vegetation taxa, in combination indicative of elevated human disturbance in the landscape, appear to have been impacting the peat swamp forest vegetation, especially in CPL & PSF sites, suggesting a loss of ecosystem resilience

④

• The majority of stakeholders of the tropical peat swamp forests of Sarawak see their development potential as their greatest asset & an important opportunity for future generations

• There is little expectation that the conversion of this ecosystem will slow, & oil palm plantation development is seen as a highly attractive & in some cases, sustainable land-use option 0% 20% 40% 60% 80% 100%

"What can you see happening to the PSF in the future?"

Percentage of Respondents

"Is it important for the next generation to have

access to PSF?"

Yes

No

Reduction

Same

Cannot predict

NA

VARIABLE PROXY INDICATED

POLLEN SUM Past vegetation composition (in ecological groups)

OPEN VEGETATION (sum of Poaceae, Cyperaceae & fern spores) Human disturbance

MICROCHARCOAL (<150µm) Regional fire

MACROCHARCOAL (>150µm) Local fire

MAGNETIC SUSCEPTIBILITY Moisture & mineral content of sediment

RADIOCARBON DATING Age-depth profile of peat core

SEDIMENT STRATIGRAPHY Sequence of sediment types

ENSO PROFILE Regional climatic changes

An investigation into the resilience and sustainable management of tropical peat swamp forests

Lydia Cole*, Shonil Bhagwat & Kathy Willis *lydia.cole@zoo.ox.ac.uk

WHAT? RESEARCH QUESTIONS

① How has the vegetation of these peat swamp forests changed through time?

② What disturbances has the ecosystem experienced & when did they occur? (i.e. fire, climatic & human drivers of perturbation)

③ How did the peat swamp forest vegetation respond to these disturbances?

④ What potential is there for sustainable peat swamp forest management?

CPL

DPLPSF Table 1 Proxies used to answer long-term ecological questions.

Development opportunities

& poverty reduction

Research & education

Water management

Ecology Reliance on forest

NA

0

2

4

6

8

10

12

14

16

Nu

mb

er

of

resp

on

de

nts

①

• Peat swamp forest (PSF & PSF+) has been the major vegetation type since peat started to accumulate in all three sites

• Fluctuations between mature & pioneer taxa have occurred throughout

WHY? THE ISSUES.... • Tropical peatlands cover c. 25 million ha in Southeast Asia (APFP, 2009), contain

high biodiversity (Posa et al., 2011) & store large amounts of carbon (Page et al., 2011)

• Rapid conversion for agriculture (mostly oil palm plantations) is threatening this habitat (Miettinen et al., 2012), disrupting ecosystem service provision for people & the environment (Phillips, 1998) & causing large quantities of CO2 emissions (Page et al., 2002)

WHERE? STUDY SITES Three sites in the coastal tropical peat swamp forests of Sarawak, Malaysian Borneo; a state where peat drainage & development is occurring at a particularly rapid rate (SarVision, 2011).

HOW? METHODS

Questions ①, ② & ③ – Long-term ecological study:

• Collected & processed three peat cores, one per site, ranging from 382cm to 285cm in depth

• Measured a variety of proxies (Table 1); counted c. 300 fossil pollen grains per sampled level (i.e. “Pollen sum”), & allocated identified taxa to ecological groups (see Fig. 3)

Question ④ – Social surveys:

• Semi-structured interviews with 40 peatland stakeholders, including smallholder farmers & oil palm plantation estate managers, government officials, non-governmental organisation employees & scientists

• Questions were asked to investigate: (a) what values stakeholders assign to this ecosystem, & (b) their perceptions of the future of peat swamp forests in Sarawak

③

• Peat swamp forest vegetation has maintained dominance during episodes of disturbance in the past

• Only in the last c. 300 years in CPL & PSF sites, is the peat vegetation showing a decline in response to disturbances

②

• Local & regional fire is present in all sites through time, to varying degrees

• Notable ↑ in local burning in the last c. 300 years across sites

• Coincides with a significant ↑ in Open Vegetation in the very recent past

• Climatic changes, linked to intensifying El Nino Southern Oscillation (ENSO), have occurred

④

• The majority of stakeholders thought that it was important for their children to have access to peat swamp forest ecosystems so they could develop them in the future for enhanced income

• Nearly 80% of stakeholders expected the peat swamp forest to continue declining in the future

IMPLICATIONS • There is no evidence from the past to suggest that tropical peat swamp forests can recover from the

anthropogenic forms of disturbance they are experiencing today

• There is a mismatch between the management strategy for this ecosystem adopted by stakeholders on the ground (i.e. conversion) & aspired to by the international conservation community (i.e. strict protection of the intact peat swamp forest for its carbon storage service)

• Policies defining tropical peat swamp forest use need to promote the precautionary principle, limiting anthropogenic disturbances to more natural levels, & address the values & aspirations of all stakeholders

Fig. 4 Stakeholder responses to questions asked.

(a)

(b)

Fig. 3 Summary diagrams showing changes in all proxies through time.

Coastal Vegetation

Other Forest

Degraded Peat

Peat Swamp Forest - pioneers

Peat Swamp Forest - mature taxa

Pollen sum

ENSO ENSO ENSO ENSO ENSO weak ENSO (wet & warm)

Macrocharcoal concentration

Microcharcoal concentration

Rate of change of TotPSF%

Palynological richness

AMS Radiocarbon Dates (yrs BP)

Age (Cal. yrs BP)

CV%

OF%DP%

PSF+%

PSF%

Sediment stratigraphy

Laminations

Peat with clay

Clay with peat

Peat

Key to sediment stratigraphy

par

ticl

es/c

m3

cm/c

m2

3to

tal

spore

s/g

rain

su

nit

dif

fere

nce

/yr

E(T

)8

3

Magnetic susceptibility

Z-4

Z-3

Z-2

Z-1

144178

160196

258213

242207

223239

236228

186243

232254

243257

272258

274250

251243

277290

265242

246253

167155

83218

5625

4153

14175

109

65

33

23

18

38

4626

2127

3463

6887

85

97

237

129

147

117

124Sum TotPSF pollen grains

%

Z-3

“Why is it important for the next generation to have access to PSF?”

Fig. 2 Map of Sarawak, within Southeast Asia, showing peatland distribution (brown) & study sites: CPL – Converted Peatland, PSF – Peat Swamp Fragment, DPL – Deforested Peatland.

CPL

PSF

DPL

All photographs taken by LC.

Fig. 1 Peatlands after various types of disturbance.

(a) Selective logging

(b) Fire

(c) Drainage for agriculture