journal of applied ecology modelling environmental and ... · of the land-sharing and land-sparing...
TRANSCRIPT
Modelling environmental and socio-economic
trade-offs associated with land-sparing and
land-sharing approaches to oil palm expansion
Janice Ser Huay Lee1*, John Garcia-Ulloa1, Jaboury Ghazoul1, Krystof Obidzinski2 and
Lian Pin Koh1,3
1Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland; 2Center for International Forestry
Research, Bogor, Indonesia; and 3Environment Institute, and School of Earth and Environmental Sciences, University
of Adelaide, Adelaide, Australia
Summary
1. The effectiveness of land-sharing and land-sparing approaches has been widely debated.
Yet, few studies quantify the environmental and socio-economic outcomes of these
approaches within a real-world landscape. Indonesia’s plans to increase its palm oil produc-
tion present an opportunity to investigate the potential environmental and socio-economic
implications of the land-sharing and sparing approaches.
2. We developed a computer model to simulate the expansion of oil palm agriculture in
Sumatra, Indonesia, under four different scenarios distinguishable by the dominance of
scheme smallholders or industrial estates: business-as-usual, BAU (25 : 75, scheme smallhold-
ers:industrial estates); high-yielding industry dominated, ESTATE (10 : 90); low-yielding
smallholder dominated, SMALLHOLDER (40 : 60), high-yielding smallholder dominated,
HYBRID (40 : 60; but with improved smallholder yields).
3. Our results reveal several trade-offs associated with varying the proportion of scheme
smallholders and productivity of oil palm plantations. The ESTATE scenario (reflecting land-
sparing) resulted in lowest environmental costs in terms of forest conversion, greenhouse gas
emissions, biodiversity losses and nitrogen fertilizer usage. Additionally, infrastructural devel-
opment and tax revenues were highest under the land-sparing approach, though fewer jobs
were created. The SMALLHOLDER scenario (indicating land-sharing) resulted in highest
environmental costs in terms of forest conversion, carbon dioxide emissions and biodiversity
losses but involved more households in oil palm agriculture and thus created more employ-
ment opportunities. The HYBRID scenario ranked second best in terms of both minimizing
forest loss and job creation. However, the drawbacks of this approach included high nitrogen
fertilizer consumption, lower infrastructural development and lower tax revenues.
4. Synthesis and applications. From an environmental perspective, it is far more important to
implement spatial restrictions on oil palm expansion over forests since increasing the produc-
tivity of smallholdings and industrial estates among the four scenarios examined show mini-
mal differences to biodiversity loss and greenhouse gas emissions. The hybrid approach
shows that increasing the proportion of scheme smallholders need not come at a great envi-
ronmental cost for achieving Indonesia’s palm oil production target. From a policy perspec-
tive, this hybrid approach requires a change in legislation to increase the minimum land area
an industrial estate owner must allocate to scheme smallholders (40%), as well as increased
support to improve productivity in oil palm smallholdings.
Key-words: agribusiness, deforestation, Elaeis guineensis, farmer, livelihoods, trade-offs,
yield intensification
*Correspondence author. E-mail: [email protected]
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society
Journal of Applied Ecology 2014 doi: 10.1111/1365-2664.12286
Introduction
Rising global demands for more food and biofuels are
driving agricultural production world-wide (WWI 2007;
Tilman et al. 2009; Cirera & Masset 2010; Kearney 2010;
Foley et al. 2011). Approximately 80% of recent agricul-
tural expansion in the tropics came at the expense of
intact and disturbed forests (Gibbs et al. 2010), raising
concerns for the fate of tropical biodiversity (Phalan et al.
2013). Some researchers advocate land-sharing, which
involves applying wildlife-friendly farming methods in
agricultural lands and integrating biodiversity conserva-
tion and agricultural production (Fischer et al. 2008;
Perfecto & Vandermeer 2008). Others argue that subopti-
mal agricultural yields resulting from this land-sharing
approach might drive agricultural expansion and convert
more natural vegetation to meet growing demands for
crops (Green et al. 2005). These critics, instead, propose a
contrasting strategy of land-sparing, which separates land
for conservation from land for agricultural production
and maximizing production on agricultural land so that
natural vegetation could be spared from agriculture
(Green et al. 2005; Phalan et al. 2011b). The effectiveness
of the land-sharing and land-sparing approaches to con-
servation in the face of rising agricultural demands has
been widely debated (Fischer et al. 2008, 2011; Tscharntke
et al. 2012). Yet, few studies have quantified the environ-
mental and socio-economic outcomes of these strategies in
relation to the biophysical and socio-economic contexts of
a real-world agricultural landscape.
Oil palm Elaeis guineensis expansion in Indonesia is a
striking example of how agricultural expansion has
impacted forests, livelihoods and biodiversity over the
last thirty years (Sheil et al. 2009). Oil palm has contrib-
uted significantly to Indonesia’s economic development
and provided an important source of employment (Zen,
Barlow & Gondowarsito 2006; Bahroeny 2009). How-
ever, its rapid expansion has also brought about environ-
mental problems (Koh et al. 2011; Carlson et al. 2013)
and social conflicts (Colchester et al. 2006). Indonesia
has plans to increase annual crude palm oil (CPO) out-
put by 69% to 40 Mt by 2020 (comparisons are made
relative to 2012 oil palm statistics) (Bahroeny 2009;
Suparno & Afrida 2009; Indonesian Ministry of Agricul-
ture 2011). This prospect of further oil palm expansion
in Indonesia presents an opportunity to examine the
potential environmental and socio-economic implications
of pursuing a land-sparing vs. land-sharing approach to
its development.
The oil palm industry in Indonesia comprises industrial
estates and oil palm smallholdings which broadly reflect
the land-sparing and land-sharing approaches to oil palm
cultivation, respectively. Industrial estates are large
commercial estates owned by either government or private
companies and are intensively managed to maximize
efficiency in plantation practices (e.g. fertilizing and
harvesting routines) (Corley & Tinker 2003). Industrial
estates are on average 5000–6000 ha in size, but can be as
large as 20 000 ha (Casson 2000; Elson 2009), and achieve
the highest CPO yields (3�60–3�77 t ha�1 y�1) among oil
palm producers in Indonesia (Indonesian Palm Oil Coun-
cil 2010). In contrast, smallholdings are between 2 and
50 ha in size with average CPO yields that are 35–40%
lower than industrial estates (Suharto 2009). Smallhold-
ings can be managed either independently by the farmer
(independent smallholders) or in association with an oil
palm company (scheme smallholders) (Zen, Barlow &
Gondowarsito 2006). In Indonesia, oil palm companies
are required by law to allocate at least 20% of their con-
cession area to affiliated scheme smallholders (OECD
2012).
Currently, approximately 40% of Indonesia’s oil palm
plantations are smallholdings and 60% are industrial
estates (Indonesian Ministry of Agriculture 2011). Within
the smallholder sector, there is an equal split between
independent and scheme smallholders (Colchester et al.
2011). Hence, the land occupied by independent small-
holdings, scheme smallholdings and industrial estates in
Indonesia is estimated to be in the ratio of 20 : 20 : 60.
This also implies that oil palm companies, on average,
allocate 25% of their concession area to scheme
smallholders.
An oil palm industry that is dominated by either indus-
trial estates or smallholdings could have different environ-
mental and livelihood implications. For example,
industrial estates have been shown to retain lower bird
diversity than smallholdings (Azhar et al. 2011). Also,
industrial estates typically use larger quantities of nitrogen
fertilizers per unit area to maintain high yields compared
to smallholders (Boer et al. 2012), which could increase
the risk of water pollution and other environmental
impacts (Sheil et al. 2009). Furthermore, more efficient
labour management in industrial estates allows them to
operate with fewer workers on a per unit area basis com-
pared to smallholdings, which might imply fewer employ-
ment opportunities, particularly for local communities
(Elson 2009). On the other hand, the development of
industrial estates is associated with greater infrastructure
development (e.g. roads), as well as higher tax revenues
for provincial and national governments, which might not
be as forthcoming from a smallholder-dominated oil palm
industry (Koh & Wilcove 2007; Gillespie 2011).
From a policy perspective, the national government has
the ability to influence the dominance of industrial estates
or smallholdings in the oil palm industry by legislating
the minimum proportion of concession area that an
industrial estate owner must allocate to its affiliated
scheme smallholders. We simulated oil palm expansion in
Sumatra, Indonesia, under four development scenarios
(Table 1) distinguishable by this particular requirement.
We did so to explore the environmental and socio-
economic implications of an oil palm industry dominated
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
2 J. S. H. Lee et al.
by industrial estates or smallholdings (i.e. land-sparing or
land-sharing approaches):
1. business-as-usual (BAU), whereby industrial estates
allocate at least 25% of their concession to scheme small-
holdings,
2. high-yielding land-sparing approach (ESTATE),
whereby this requirement was reduced to 10% of conces-
sion area,
3. low-yielding land-sharing approach (SMALL-
HOLDER), whereby this requirement was increased to
40% of concession area. This proportion of smallholder
affiliation is not unprecedented as the original smallholder
schemes (nucleus estate schemes) developed in Indonesia
in the late 1960s were based on a land allocation ratio of
60 : 40, 70 : 30 or 80 : 20 in favour of scheme smallhold-
ers (McCarthy 2010). In recent years, this land allocation
ratio has reversed (McCarthy, Vel & Afiff 2012), possibly
to increase tax and export revenues from industrial estates
(Gillespie 2011).
4. high-yielding land-sharing scenario (HYBRID),
whereby industrial estates allocate at least 40% of their
concession area to scheme smallholdings (same as the
SMALLHOLDER scenario) and the CPO yield gap
between industrial estates and smallholdings was reduced.
In this case, CPO yields from independent and scheme
smallholdings would be increased by 49% and 18%,
respectively (see Materials and methods), due primarily to
increased use of fertilizers, pesticides and higher quality
seeds, and improved labour efficiency (Zen, Barlow &
Gondowarsito 2006; Boer et al. 2012). The Indonesian
government and international organizations would
provide the institutional support for these improvements
(Drajat 2010; World Bank 2011; Yulisman 2011; Boer
et al. 2012). Indeed, increasing smallholder productivity is
one of the main aims of the Indonesian Sustainable Palm
Oil initiative (UNDP 2012), and has been identified by
World Bank as one of its key criteria for re-engagement
with the Indonesian oil palm industry (World Bank 2011).
It is important to note that these scenarios are distin-
guished by the dominance of industrial estates or scheme
smallholders. The proportion of independent smallholders
would remain at 20% of total oil palm area in Indonesia
across all scenarios since the expansion of independent
smallholdings is not regulated under any of Indonesia’s
laws, and the lack of baseline data on independent small-
holder oil palm expansion limits our ability to confidently
predict the growth of independent smallholdings. We
developed a computer model to simulate the expansion of
oil palm agriculture in Indonesia under these four devel-
opment scenarios, and compared the resultant environ-
mental (forest loss, biodiversity loss, net carbon
emissions, nitrogen fertilizer usage) and socio-economic
(employment, road development, tax revenues) outcomes.
Materials and methods
OIL PALM EXPANSION AND PRODUCTION TARGETS
In 2012, the estimated area of oil palm cultivation in Indonesia
was ~9�3 Mha (Indonesian Ministry of Agriculture 2011), of
which 71�7% (~6�7 Mha) was mature oil palm plantations pro-
ducing ~23�6 Mt y�1 of CPO. In order to meet the Indonesian
Ministry of Agriculture’s production target of 40 Mt y�1 of
CPO, Indonesia needs to produce an additional ~16�4 Mt y�1 of
CPO. If we assume that the production capacity of existing
immature oil palm plantations would contribute to future pro-
duction (i.e., ~9�3 Mt y�1 CPO from ~2�6 Mha of plantations at
2012 national average yield 3�55 t ha�1 y�1), Indonesia would
still need to produce an additional ~7�1 Mt y�1 of CPO in order
to reach its production target. Based on the percentage contribu-
tion of Sumatra to national CPO production (69�7%; see Appen-
dix S1, Supporting information) (Indonesian Ministry of
Agriculture 2010), we estimated that Sumatra would need to
increase its CPO production by ~4�9 Mt y�1. We included only
Sumatra in our analysis as Sumatra contributes to the bulk
(69�7%) of Indonesia’s oil palm production.
OIL PALM YIELDS OF SMALLHOLDINGS
We obtained data on average yields of FFB in independent small-
holdings, scheme smallholdings and industrial estates from two
meta-analytical papers (Zen, Barlow & Gondowarsito 2006; Boer
et al. 2012). Based on these data, we derived the average relative
yield of independent (~44%) and scheme (~76�6%) smallholdings
compared to industrial estates (see Appendix S1, Supporting
information). These values were used in our calculations of FFB
production in the BAU, SMALLHOLDER and ESTATE model
scenarios. The same studies also reported potential improvements
in FFB yields in smallholdings through better management and
production practices (Zen, Barlow & Gondowarsito 2006; Boer
Table 1. Proportion of land area under independent smallhold-
ings, scheme smallholdings and industrial estates under our four
model scenarios. Scheme smallholdings and Industrial estates
make up 80% of the land area across all scenarios while Indepen-
dent smallholdings make up 20% of the land area. Relative yields
for smallholdings were increased under the HYBRID scenario.
See Table S2 (Supporting information) for more information on
relative yields
Scenarios
BAU ESTATE
SMALL
HOLDER HYBRID
Proportion of land area
Independent
smallholdings
20 20 20 20
Scheme
smallholdings
20 8 32 32
Industrial
estates
60 72 48 48
Relative yields (%)
Independent
smallholdings
43�9 43�9 43�9 65�5
Scheme
smallholdings
76�6 76�6 76�6 90
Industrial
estates
100 100 100 100
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
Simulating oil palm expansion in Sumatra 3
et al. 2012). We derived that, under these improved conditions,
the relative yield of independent and scheme smallholdings would
increase to 65�5% (i.e., a 49% improvement) and 90% (18%
improvement), respectively (see Table S2, Supporting informa-
tion). These values for improved yields were used in our
HYBRID scenario.
SPATIAL DATA BASE
We generated a raster data base at 100-ha grid cell resolution
containing information on several key biophysical and infrastruc-
tural attributes for Sumatra using the following geographic infor-
mation systems (GIS) layers: land cover, above-ground biomass
carbon, peatlands, suitability for oil palm cultivation, existing
road networks, existing oil palm mills, existing shipping ports
and locations of capital cities and towns (see Appendix S1,
Supporting information). We excluded regions with missing
spatial data as well as unsuitable areas for oil palm expansion
such as urban areas, water bodies, islands, areas higher than
1000 m in altitude, montane land classes, areas under an oil
palm, timber or logging concession, areas zoned as settlements
and protected areas (see Appendix S1, Supporting information).
Variation in yield potential due to soil type and climate variables
was taken into account under our suitability map for oil palm
cultivation derived from the Global Agro-Ecological Zones
(Fischer et al. 2001). This data base was compiled into a data
frame in R using the ‘raster’ package for subsequent analyses
(R Development Core Team, 2008; Hijmans & Etten 2012).
SIMULATING OIL PALM EXPANSION
We simulated oil palm expansion in Sumatra by assigning ‘conver-
sion priorities’ to each grid cell based on the biophysical and in-
frastructural attributes described above. Furthermore, we
considered that different oil palm producers might respond differ-
ently to different attributes. We assumed that distance to oil palm
mills, roads, capital cities and main towns would have the strong-
est influence on a grid cell being converted to an independent
smallholding. Based on these attributes, each grid cell is assigned
a conversion priority index for it becoming an independent small-
holding (Pids; see Appendix S1, Supporting information).
On the other hand, an industrial estate developer who has the
resources to build new roads and oil palm mills might have a dif-
ferent set of criteria for deciding where to establish a new planta-
tion. Scheme smallholders would have similar criteria as they
typically rely on the estate developer for plantation management
and FFB processing (Vermeulen & Goad 2006). We assumed that
distance to shipping ports, contiguity of suitable land, and agri-
cultural suitability of the land for oil palm development would
have the highest weighting on a grid cell becoming an industrial
estate or scheme smallholder. Based on these attributes, each grid
cell is also assigned a second conversion priority index for it
becoming an industrial estate or scheme smallholding (Pcps; see
Appendix S1, Supporting information).
During the first part of the simulation, each grid cell was
labelled as an independent smallholding if Pids > Pcps; conversely,
if Pids < Pcps the grid cell would be labelled as either an industrial
estate or scheme smallholding, based on the ratio defining each
model scenario (e.g. 90 : 10 in ESTATE scenario). This part of
the simulation produced 159 097 grid cells labelled as indepen-
dent smallholdings, and 103 508 grid cells labelled as industrial
estates or scheme smallholdings. In order to maintain the propor-
tion of independent smallholdings at 20% of total oil palm
planted area in Sumatra, 133 641 grid cells were randomly
selected and excluded from subsequent analyses, leaving 25 456
grid cells representing independent smallholdings. It is important
to note that a different set of grid cells was excluded for each run
of the simulation.
During the second part of the simulation, the pool of 128 964
grid cells (25 456 independent smallholding cells and 103 508
industrial estates/scheme smallholding cells) was converted to oil
palm one cell at a time until FFB production reaches the produc-
tion target for Sumatra (21�7 Mt y�1). The order of conversion
of these cells into oil palm was quasi-random, weighted by a gen-
eral conversion priority index based on distance to roads, capital
cities and towns (Pgen; see Appendix S1, Supporting information).
Suitable regions for scheme smallholding and industrial estate
expansion were clustered in the middle of the island possibly due
to higher weighting given to the contiguity of suitable land under
our Pcps (Fig. 1). Our simulation model was coded in R (R Devel-
opment Core Team, 2008).
MEASURING OUTCOME VARIABLES
We performed a total of 10 000 runs for each model simulation
and obtained the average values for the following outcome vari-
ables: area of different land cover types converted to oil palm,
above-ground biomass and peat soil carbon losses to oil palm,
area of independent smallholdings, area of scheme smallholdings
and area of industrial estates.
Additionally, we calculated bird biodiversity outcomes based
on the projected areas of land cover converted to oil palm small-
holdings and industrial estates under each scenario using the
matrix calibrated species area model developed by Koh &
Ghazoul (2010a) (see Appendix S1, Supporting information). We
estimated net changes in carbon dioxide emissions by considering
(i) changes in biomass from land cover change (above-ground
biomass loss and peat soil carbon losses via oxidation as well as
carbon biomass gain in oil palm plantations) under a burning
and a non-burning scenario, and (ii) greenhouse gas emissions
from nitrogen fertilizer use (see Appendix S1, Supporting infor-
mation). We quantified nitrogen fertilizer usage, employment,
road development and tax revenue based on projected areas of
independent smallholdings, scheme smallholdings and industrial
estates in Sumatra upon reaching its oil palm production target
(see Appendix S1, Supporting information).
Results
Under the BAU scenario, our model predicted an expan-
sion of 1699 700 ha of oil palm plantations in Sumatra to
meet its FFB production target of 21�7 Mt y�1. The
ESTATE scenario (land-sparing) led to a reduction of this
area requirement by ~3�5% (i.e., predicted expansion of
1640 300 ha), while the SMALLHOLDER scenario (land-
sharing) led to an increase of ~4% in oil palm expansion
(i.e., 1763 500 ha) compared to the BAU scenario. The
HYBRID scenario (high-yield land-sharing) predicted an
expansion of 1645 200 ha of oil palm plantations, which
is just ~5000 ha higher than that of the ESTATE
scenario, and 3�2% lower than BAU.
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
4 J. S. H. Lee et al.
Across all scenarios, oil palm expansion occurred pre-
dominantly over the following land cover categories
(Fig. 2): lowland mosaic (645 442–693 993 ha; 39�6%),
plantation or regrowth forests (564 447–606 797 ha;
34�4%) and lowland open (281 412–302 517 ha; 17�5%).
In comparison, the extent of oil palm expansion on low-
land forests and peatswamp forests was considerably
lower [lowland: 7�2% (117 291–126 126 ha); peatswamp:
1�4% (23 354–25 098 ha)]. The extent of oil palm expan-
sion over peatlands (which include both peatswamp for-
ests and non-forested land cover and which collectively
are an important reservoir of below-ground carbon)
amounted to ~9% (153 752–165 197 ha) across all four
scenarios.
The above model results on oil palm area requirements
were based on the mean relative yields of FFB derived for
independent and scheme smallholdings (Table S2, Support-
ing information). In a sensitivity analysis, we applied low
and high estimates of relative FFB yields for independent
and scheme smallholdings (Table S2, Supporting informa-
tion) to calculate the area of oil palm required to reach
Sumatra’s FFB production target (Table S8, Supporting
information). Under low estimates of relative yields for
independent and scheme smallholdings, the area of oil
palm predicted under the BAU scenario was 1760 300 ha,
and the ESTATE scenario accounted for the least amount
of land used (5�5% less than BAU). Under high estimates
of relative yields, the area of oil palm predicted under the
BAU scenario was 1643 100 ha, and the HYBRID
scenario accounted for the least amount of land used
(4�5% less than BAU) (Table S8, Supporting information).
Projected area of total oil palm expansion using low and
high relative yields for each scenario varied by 1–6%
compared to the use of mean estimates of relative yields
(Fig. S1, Supporting information).
The ESTATE scenario led to the lowest environmental
costs in terms of peatswamp and lowland forest loss and
peatland conversion (Table 2, Fig. 3a,b). The ESTATE
scenario also led to lower total nitrogen fertilizer usage
compared to the BAU and SMALLHOLDER scenarios
(Fig. 3c), even though on a per unit area basis nitrogen
fertilizer usage was second highest in the ESTATE sce-
nario (4�1 Nt ha�1). Net greenhouse gas emissions derived
from land cover change and nitrogen fertilizer usage was
lowest under the ESTATE scenario, followed by the
HYBRID scenario, BAU scenario and SMALLHOLDER
scenario (Fig. 3b). Oil palm expansion in Sumatra would
result in the loss of 0�27% of bird diversity under the
ESTATE scenario (equivalent to the local extirpation of
two bird species), which is only slightly lower than the
(a)
(b)
(c)
(d)
Fig. 1. Suitable regions determined by conversion priority indices for oil palm expansion under the (a) BAU, (b) ESTATE, (c) SMALL-
HOLDER and (d) HYBRID scenarios. The large figure of Sumatra reflects the BAU scenario.
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
Simulating oil palm expansion in Sumatra 5
loss of bird diversity under the BAU (0�28%) or SMALL-
HOLDER (0�29%) scenarios (Table 2).
Oil palm development under the ESTATE scenario gen-
erated a total of US$5�4 billion in tax revenues at the
national level, which was significantly higher than reve-
nues generated by the BAU (US$ 4�7 billion), SMALL-
HOLDER (US3�9 billion) and HYBRID (US 3�6 billion)
scenarios (Fig. 4a). A similar trend can be observed for
tax revenues at the provincial and district levels (Fig. 4b).
The ESTATE scenario also resulted in better infrastruc-
tural development in terms of road construction
(80 991 km) compared to the BAU (79 580 km),
SMALLHOLDER (78 781 km) and HYBRID
(73 343 km) scenarios (Fig. 4c). However, the ESTATE
scenario created the fewest jobs (245 102) compared to
the BAU (268 304), SMALLHOLDER (293 259) and
HYBRID (273 610) scenarios (Fig. 4d).
Discussion
Indonesia’s rapidly expanding oil palm industry is both
an important source of revenue for the economy and an
immediate threat to carbon-rich and biodiverse forests.
This has led to an urgent need to identify future
development pathways that could reconcile environmental
and socio-economic priorities of oil palm expansion in
the country (Sandker, Suwarno & Campbell 2007; Koh
& Ghazoul 2010b; Wicke et al. 2011; Sayer et al. 2012;
Carlson et al. 2013). Here, we modelled the environmen-
tal and socio-economic outcomes from a land-sparing vs.
land-sharing approach reflecting alternative policy
changes to the scheme smallholder initiative. From a bio-
diversity conservation perspective, our results show that
biodiversity losses derived from a land-sparing approach
are lower than a land-sharing approach, though the dif-
ferences are slight among all scenarios. This indicates
that the main determinant of biodiversity losses from oil
palm expansion depends not on who grows oil palm but
where expansion occurs. Therefore, spatial restrictions on
oil palm expansion over forests could be a priority for
conservation efforts, since differences in oil palm yields
appear to have little influence. However, it is important
to note here that our biodiversity outcomes were based
on species richness of bird taxa which could limit our
approach in two ways. First, birds represent only one
group of species, and being volant, are able to resist
land-use changes. Secondly, our use of species richness as
an indicator for biodiversity may not be the best
0
100 000
200 000
300 000
400 000
500 000
600 000
700 000
800 000
Mangrove Peatswamp forest Lowland forest Plantation/regrowth forest
Lowland mosaic Lowland open
Are
a co
nver
ted
to o
il pa
lm (h
a)
Land cover
BAUESTATESMALLHOLDERHYBRID
Fig. 2. Extent of land cover converted to
oil palm predicted by our model under the
BAU, ESTATE, SMALLHOLDER, and
HYBRID scenarios. Error bars represent
the sensitivity of land cover outcomes to
low (top error bar) and high (bottom error
bar) estimates of FFB yields drawn from
Table S2 (Supporting information). The
95% confidence intervals for land cover
outcomes are presented in Table S9
(Supporting information).
Table 2. Mean (� SD) values of outcome variables for oil palm plantations, peatland conversion and biodiversity losses averaged over
10 000 runs from our computer model simulation. Values in parentheses represent the 95% confidence interval range. Biodiversity loss is
represented as the percentage of bird species extinction (see Supporting Information for more details). Please refer to Table S8 (Support-
ing information) for oil palm expansion under low and high yield estimates
Oil palm plantations (ha)
Scenario
Oil palm
expansion
(ha)
Independent
smallholdings Scheme smallholdings Industrial estates
Peatland converted
(ha)
Biodiversity
losses (%)
BAU 1699 700 335 472 � 4879 341 068 � 4844 1023 158 � 5946 159 306 � 3593 0�286 � 5�991(335 376; 335 568) (340 973; 341 163) (1023 041; 1023 275) (159 236; 159 376) (0�169; 0�403)
ESTATE 1640 300 323 813 � 4766 131 596 � 3230 1184 890 � 5351 153 752 � 3590 0�277 � 5�987(323 720; 323 906) (131 533; 131 659) (1184 785; 1184 995) (153 682; 153 822) (0�160; 0�394)
SMALL
HOLDER
1763 500 348 002 � 4944 566 258 � 5755 849 238 � 6158 165 197 � 3718 0�296 � 6�021(347 905; 348 099) (566 145; 566 371) (849 117; 849 359) (165 124; 165 270) (0�178; 0�414)
HYBRID 1645 200 324 836 � 4764 528 154 � 5650 792 209 � 5996 154 172 � 3596 0�278 � 5�989(324 743; 324 929) (258 043; 528 265) (792 091; 792 327) (154 102; 154 242) (0�161; 0�395)
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
6 J. S. H. Lee et al.
approach in evaluating land-sparing and land-sharing
strategies (Phalan et al. 2011a). Instead, species abun-
dance or population density within these landscapes
under different production systems (smallholdings and
industrial estates) could be considered (Phalan et al.
2011a). It is also important to note that our model may
overestimate biodiversity losses from smallholdings since
our simulation occurred in blocks of 100 ha units which
may introduce greater habitat fragmentation and resem-
ble a more homogenous landscape than we would expect
smallholdings to be. Concerning oil palm agriculture,
most studies propose a high-yielding land-sparing
approach to conserve biodiversity (e.g. Phalan et al.
(2009), Edwards et al. (2010), Phalan et al. (2011b)).
However, these studies (including ours) do not account
for possible expansion following intensification driven by
higher agricultural land rents (Angelsen 1999; Nantha &
Tisdell 2009) as illustrated by Phelps et al. (2013) in the
Congo Basin.
Based on the results of our model, the contribution of
forested land towards reaching Sumatra’s palm oil pro-
duction target is small (<10% of total expansion area),
suggesting that improving forest protection will not
greatly compromise palm oil production. Lowland forest
conversion predicted from our model (~120 000 ha) was
approximately 1�2–1�4 times lower compared to lowland
forest loss within Sumatra’s oil palm industry from 2000
to 2010 (~290 000 ha) (Lee et al. 2013a). The extent of
peatswamp forest conversion predicted from our model
was much lower (~24 000 ha; 14�2–15�4 times lower) com-
pared to peatswamp forest loss from 2000 to 2010
(~380 000 ha). The reduced extent of peatswamp forest
conversion may reflect (i) lower extents of forested peat-
lands in 2010 (1�8 Mha) as compared to 2000 (3�1 Mha)
in Sumatra, and/or (ii) the relative importance placed on
biophysical and geographical attributes as compared to
socio-political attributes in determining oil palm expan-
sion in our model (Casson 2000; Irawan, Tacconi & Ring
2013).
Non-forested peatlands constitute more than 80% of
projected peatland conversion to oil palm in our model.
While converting non-forested peatlands is certainly less
damaging than converting forested peatlands from a bio-
diversity conservation perspective, there could be severe
carbon emission impacts from the conversion of any peat-
lands into oil palm due to the drainage process associated
with cultivating oil palm on peat (Koh et al. 2011; Page
et al. 2011; Moore et al. 2013). We show that large
extents of non-forested peatlands are situated in favour-
able oil palm production regions and if not restored, are
likely to be converted into oil palm, accounting for 25–
34% of gross carbon emissions (84–125 Mt C; range
reflecting the minimum and maximum values from a no
burning and burning scenario) over a 25-year oil palm
plantation cycle. To reduce carbon emissions while reach-
ing Sumatra’s palm oil production target, a prohibition
on planting over peatlands is crucial.
Employment, road development and increased tax bene-
fits from the oil palm industry are often cited by local
and central authorities for expanding the oil palm sector
in Indonesia (Bahroeny 2009; Indonesian Ministry of
Economic Affairs 2011). We show within our land-sharing
scenarios (SMALLHOLDER, HYBRID), increasing the
proportion of land allocated to smallholders leads to a
higher number of jobs but results in lower road develop-
ment and tax revenues compared to an industrial expan-
sion of oil palm (ESTATE). The higher tax revenues
generated from the ESTATE scenario (Fig. 4a,b) indicate
a high economic incentive that might favour industrial
estate development over smallholdings. While increasing
employment and road development can spur greater rural
development, they might also impact rural population
dynamics by increasing the rate of migration as demon-
strated in Riau (Susanti & Burgers 2012; Budidarsono,
Susanti & Zoomers 2013). The impact of migration on
the long-term sustainability of oil palm development is
beyond the scope of our analysis but warrants future
research. Often, job creation, increased tax revenues and
road construction are seen as positive socioeconomic indi-
cators in developing countries. However, it is important
to note that labour conditions vary widely within oil palm
plantations (Li 2011; Skinner 2013), government revenues
have been mismanaged (Human Rights Watch 2013), and
roads could lead to further environmental degradation
(Chomitz & Gray 1996; Gaveau et al. 2009). Our results
provide only socio-economic figures but are unable to
paint the context of successful development of these indi-
cators, which rely crucially on effective governance.
Agricultural lands and secondary regrowth comprised
the bulk of land cover converted to oil palm under our
model simulations (Fig. 2). These largely agricultural
areas may come under existing ownership by local com-
munities and incur high social costs should a purely
industrial estate expansion occur. Allocating a higher pro-
portion of land for smallholder agriculture such as that
defined under our SMALLHOLDER and HYBRID sce-
nario may help mitigate social conflicts over land grab-
bing issues and spread the benefits of oil palm production
among local communities. Assuming that the average oil
palm smallholding is 2 ha (Lee et al. 2013b), the potential
number of households which can be supported by oil
palm agriculture would amount to 457 130 and 426 495
households under a SMALLHOLDER and HYBRID sce-
nario, respectively, approximately twice the number of
smallholder households involved under a ESTATE sce-
nario (227 704 households) (Appendix S1, Supporting
information). Linking smallholder oil palm development
with pro-poor policies such as involving landless farmers
could also contribute towards reducing the number of
landless farmer households, which was reported in 2003
to be ~1�7 million for the island of Sumatra (Badan Pusat
Statistik 2004; Zen, McCarthy & Gillespie 2008). How-
ever, success of Indonesian smallholder oil palm develop-
ment varies (Rist, Feintrenie & Levang 2010; McCarthy,
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
Simulating oil palm expansion in Sumatra 7
Gillespie & Zen 2012), and partnerships with oil palm
smallholders need to be transparent and established
under fair and equitable conditions [see Cramb (2013),
McCarthy (2010), Li (2011), and McCarthy, Gillespie &
Zen (2012) for varying outcomes of smallholder oil palm
development].
Our HYBRID scenario appears to be the best compro-
mise between environmental and socio-economic out-
comes for achieving Indonesia’s crude palm oil
production target. Less land is converted, and more small-
holder households were involved as well as employment
opportunities created under this HYBRID approach. The
drawbacks, however, include increased nitrogen fertilizer
consumption as well as lower road development and tax
revenues generated. In the last International Conference
on Oil Palm and the Environment 2012 meeting in Bali,
smallholder yield intensification was raised as an example
to increase palm oil production without resulting in rising
land demands (Widjaja 2012). Indeed initiatives such as
the Smallholder Acceleration Reducing Emissions from
Deforestation and Degradation Plus (REDD+) Program
(SHARP - http://www.sharp-partnership.org/) are finding
solutions for reduced deforestation and improved rural
livelihoods via increased yields from smallholder agricul-
tural production, including oil palm. While these initia-
tives are laudable for enhancing smallholder agriculture
and empowering smallholders, the link between deforesta-
tion and increased yields is complex (Angelsen 1999;
0
1
2
3
4
5
6
7
8
Tota
l Nit
roge
n fe
rtili
zer
usag
e (M
t)
0
20 000
40 000
60 000
80 000
100 000
120 000
140 000
160 000
Are
a of
fore
st lo
ss (h
a)
Peatswamp forest Lowland forest(a)
(b)
(c)
0
200
400
600
800
1000
1200
BAU ESTATE SMALLHOLDER HYBRID
BAU ESTATE SMALLHOLDER HYBRID
BAU ESTATE SMALLHOLDER HYBRID
Net
gre
enho
use
gas
emis
sion
s fr
om la
ndco
ver
chan
ge a
nd N
itro
gen
fert
ilize
r us
age
(Mt)
Burning No burning
Fig. 3. Environmental outcomes for (a)
forest cover loss, (b) net greenhouse gas
emissions and (c) total nitrogen fertilizer
usage predicted by our model under the
BAU, ESTATE, SMALLHOLDER and
HYBRID scenarios. Error bars represent
the sensitivity of environmental outcomes
to low (top error bar) and high (bottom
error bar) estimates of fresh fruit bunch
yields drawn from Table S2 (Supporting
information). The 95% confidence inter-
vals for environmental outcomes are pre-
sented in Table S10 (Supporting
information).
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
8 J. S. H. Lee et al.
Fischer et al. 2011) and relies crucially on effective land-
use planning to avoid increased deforestation (Balmford,
Green & Phalan 2012). While more land is spared under
the HYBRID scenario, increased smallholder incomes
from oil palm production may lead to further land con-
version as wealthy smallholders acquire more land to
increase oil palm cultivation (McCarthy 2010). In Indone-
sia, other socio-political complexities of oil palm expan-
sion also exist, such as high economic incentives for local
authorities to allocate forested land for oil palm establish-
ment (Irawan, Tacconi & Ring 2013). These institutional
problems may continue to drive the expansion of high-
yielding oil palm plantations over forests as demonstrated
in Peru (Guti�errez-V�elez et al. 2011).
CONCLUSION
Using spatially explicit information on various important
attributes for oil palm expansion, we developed a com-
puter model to simulate different pathways of oil palm
expansion in Indonesia, and considered the environmental
and socio-economic outcomes of pursuing oil palm expan-
sion in Sumatra via a land-sparing, land-sharing, and a
hybrid approach. We demonstrate that the hybrid
approach generated the best compromise between envi-
ronmental and socio-economic outcomes from oil palm
expansion (Fischer et al. 2008). However, it is important
to note two limitations of our model: (i) we did not
account for complex socio-political determinants of oil
palm expansion, and (ii) we could not capture long-term
economic decisions towards land-use change from oil
palm smallholders who benefited from yield intensifica-
tion. Nevertheless, our model does show the value of
increasing oil palm land allocation to smallholders to
involve more local communities in oil palm production,
increase employment opportunities and potentially reduce
poverty in rural parts of Sumatra. We also demonstrate
that land spared from high-yielding oil palm expansion
led to lower biodiversity losses than low-yielding oil palm
expansion, though differences were very slight.
As Indonesia moves forward to reach its 40 Mt y�1
CPO production target, we show the value of investing in
high yields and increasing company–community partner-
ships to move towards a more equitable land-sharing and
sparing arrangement for future oil palm production. This,
however, needs to be coupled with effective land-use plan-
ning to avoid escalating deforestation from increasing oil
palm yields. We see the need for further research into the
impacts of migration resulting from oil palm development
as well as examining smallholder household dynamics to
provide insights as to whether our hybrid approach can
be a long-term sustainable solution for oil palm expansion
in Indonesia.
Acknowledgements
We thank B. Azhar for sharing data on bird diversity from oil palm plan-
tations, S. Fux and U. Borstnik for technical support, and Z. Burivalova
0
1000
2000
3000
4000
5000
6000
BAU ESTATE SMALLHOLDER HYBRID BAU ESTATE SMALLHOLDER HYBRID
BAU ESTATE SMALLHOLDER HYBRIDBAU ESTATE SMALLHOLDER HYBRID
Nat
iona
l rev
enue
(mill
ion
USD
)
National
0
5
10
15
20
25
Reve
nue
(mill
ion
USD
)
Provincial
District
0
50 000
100 000
150 000
200 000
250 000
300 000
350 000
Empl
oym
ent (
no. j
obs)
0
10 000
20 000
30 000
40 000
50 000
60 000
70 000
80 000
90 000
Road
dev
elop
men
t (km
)
(a)
(d)(c)
(b)
Fig. 4. Socio-economic outcomes for (a) national tax revenues, (b) provincial and district tax revenues, (c) road development and (d)
employment predicted by our model under the BAU, ESTATE, SMALLHOLDER, and HYBRID scenarios. Error bars represent the
sensitivity of socio-economic outcomes to low (top error bar) and high (bottom error bar) estimates of fresh fruit bunch yields drawn
from Table S2 (Supporting information). The 95% confidence intervals for socio-economic outcomes are presented in Table S11
(Supporting information).
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
Simulating oil palm expansion in Sumatra 9
for helpful comments. J.S.H.L. is supported by the Swiss National Science
Foundation (SNF 0-12818-06). J.G.U. is supported by the Mercator Foun-
dation Switzerland and the Zurich-Basel Plant Science Center.
References
Angelsen, A. (1999) Agricultural expansion and deforestation: modelling
the impact of population, market forces and property rights. Journal of
Development Economics, 58, 185–218.Azhar, B., Lindenmayer, D.B., Wood, J., Fischer, J., Manning, A.,
McElhinny, C. & Zakaria, M. (2011) The conservation value of oil palm
plantation estates, smallholdings and logged peat swamp forest for
birds. Forest Ecology and Management, 262, 2306–2315.Badan Pusat Statistik (2004) Sebaran Rumah Tannga Pertanian dan
Rumah Tangga Petani Gurem menurut Propinsi di Indonesia. Berita
Resmi Statistik No. 14/VII. Badan Pusat Statistik, Jakarta.
Bahroeny, J. (2009) Palm oil as an economic pillar of Indonesia. (http://
www.thejakartapost.com/news/2009/12/02/palm-oil-economic-pillar-
indonesia.html) [Accessed on 1 November 2013].
Balmford, A., Green, R. & Phalan, B. (2012) What conservationists need
to know about farming. Proceedings of the Royal Society B: Biological
Sciences, 279, 2714–2724.Boer, R., Nurrochmat, D.R., Ardiansyah, M., Hariyadi, Purwawangsa, H.
& Ginting, G. (2012) Reducing agricultural expansion into forests in
Central Kalimantan - Indonesia. Center for Climate Risk and Opportu-
nity Management, Bogor Agricultural University, Bogor, Indonesia.
Budidarsono, S., Susanti, A. & Zoomers, A. (2013) Oil Palm Plantations
in Indonesia: The Implications for Migration, Settlement/Resettlement
and Local Economic Development. InTech, http://www.intechopen.com/
books/export/citation/EndNote/biofuels-economy-environment-and-
sustainability/oil-palm-plantations-in-indonesia-the-implications-for-
migration-settlement-resettlement-and-local-e [Accessed on 1 November
2013].
Carlson, K.M., Curran, L.M., Asner, G.P., Pittman, A.M., Trigg, S.N. &
Marion Adeney, J. (2013) Carbon emissions from forest conversion by
Kalimantan oil palm plantations. Nature Climate Change, 3, 283–287.Casson, A. (2000) The Hesitant Boom: Indonesia’s Oil Palm Sub-Sector in
an Era of Economic Crisis and Political Change. Center for International
Forestry Research, Bogor, Indonesia. pp. 55.
Chomitz, K.M. & Gray, D.A. (1996) Roads, land use, and deforestation:
a spatial model applied to belize. The World Bank Economic Review, 10,
487–512.Cirera, X. & Masset, E. (2010) Income distribution trends and future food
demand. Philosophical Transactions of the Royal Society B Biological
Sciences, 365, 2821–2834.Colchester, M., Boscolo, M., Contreras-Hermosilla, A., Gatto, F.D.,
Dempsey, J., Lescuyer, G. et al. (2006) Justice in the forest: rural liveli-
hoods and forest law enforcement. Center for International Forestry
Research (CIFOR), Bogor, Indonesia.
Colchester, M., Chao, S., Dallinger, J., Sokhannaro, H.E.P., Dan, V.T. &
Villanueva, J. (2011) Oil Palm Expansion in South East Asia: Trends
and implications for local communities and indigenous peoples. Forest
Peoples Programme and Perkumpulan Sawit Watch.
Corley, R.H.V. & Tinker, P.B.H. (2003) The Oil Palm (World Agriculture
Series). Balckwell Publishing Limited, Oxford.
Cramb, R.A. (2013) Palmed off: incentive problems with joint-venture
schemes for oil palm development on customary land. World Develop-
ment, 43, 84–99.Drajat, B. (2010) The contribution and challenges of smallholders in the
oil palm industry. The Jakarta Post. (http://www.thejakartapost.com/
news/2010/12/03/the-contribution-and-challenges-smallhold-
ers-oil-palm-industry.html) [Accessed on February 2013].
Edwards, D.P., Hodgson, J.A., Hamer, K.C., Mitchell, S.L., Ahmad,
A.H., Cornell, S.J. & Wilcove, D.S. (2010) Wildlife-friendly oil palm
plantations fail to protect biodiversity effectively. Conservation Letters,
3, 236–242.Elson, D. (2009) Palm Oil Business Models for Land Use and Develop-
ment Planning in Indonesia. Prepared for the Indonesian National
Development Planning Agency (BAPPENAS) as part of a project sup-
ported by UK Department for International Development.
Fischer, G., Shah, M., van Velthuizen, H. & Nachtergaele, F.O. (2001)
Global Agro-ecological Assessment for Agriculture in the 21st Century.
International Institute for Applied Systems Analysis, Laxenburg,
Austria.
Fischer, J., Brosi, B., Daily, G.C., Ehrlich, P.R., Goldman, R., Goldstein,
J. et al. (2008) Should agricultural policies encourage land sparing or
wildlife-friendly farming? Frontiers in Ecology and the Environment, 6,
380–385.Fischer, J., Bat�ary, P., Bawa, K.S., Brussaard, L., Chappell, M.J., Clough,
Y. et al. (2011) Conservation: limits of land sparing. Science, 334, 593.
Foley, J.A., Ramankutty, N., Brauman, K.A., Cassidy, E.S., Gerber, J.S.,
Johnston, M. et al. (2011) Solutions for a cultivated planet. Nature,
478, 337–342.Gaveau, D., Wich, S., Epting, J., Juhn, D., Kanninen, M. & Leader-Wil-
liams, N. (2009) The future of forests and orangutans (Pongo abelii) in
Sumatra: predicting impacts of oil palm plantations, road construction,
and mechanisms for reducing carbon emissions from deforestation.
Environmental Research Letters, 4, 11.
Gibbs, H.K., Ruesch, A.S., Achard, F., Clayton, M.K., Holmgren, P.,
Ramankutty, N. & Foley, J.A. (2010) Tropical forests were the primary
sources of new agricultural land in the 1980s and 1990s. Proceedings of
the National Academy of Sciences of the United States of America, 107,
16732–16737.Gillespie, P. (2011) How does legislation affect oil palm smallholders in
the Sangga district of Kalimantan, Indonesia? Australasian Journal of
Natural Resources Law and Policy, 14, 1–44.Green, R.E., Cornell, S.J., Scharlemann, J.P.W. & Balmford, A. (2005)
Farming and the fate of wild nature. Science, 307, 550–555.Guti�errez-V�elez, V.H., DeFries, R., Pinedo-V�asquez, M., Uriarte, M.,
Padoch, C., Baethgen, W., Fernandes, K. & Lim, Y. (2011) High-yield
oil palm expansion spares land at the expense of forests in the Peruvian
Amazon. Environmental Research Letters, 6, 044029.
Hijmans, R.J. & Etten, J.V. (2012) Raster: Geographic analysis and mod-
eling with raster data. R package version 2.0-12.
Human Rights Watch (2013) The Dark Side of Green Growth. Human
Rights Impacts of Weak Governance in Indonesia’s Forestry Sector.
Human Rights Watch, USA.
Indonesian Ministry of Agriculture (2010) Rencana Strategis. Pembang-
unan Perkebunan 2010 - 2014. Direktorat Jenderal Perkebunan, Kemen-
terian Pertanian, Jakarta.
Indonesian Ministry of Agriculture (2011) Tree Crop Estate Statistics of
Indonesia 2010-2012 Oil Palm. (ed. Directorate General of Plantations).
Jakarta.
Indonesian Ministry of Economic Affairs (2011) Masterplan for Accelera-
tion and Expansion of Indonesia Economic Development 2011–2025 Min-
istry for Economic Affairs. Ministry of National Development Planning/
National Development Planning Agency, Jakarta, Indonesia.
Indonesian Palm Oil Council (2010) Indonesian Palm Oil in Numbers 2010.
Indonesian Palm Oil Producers Association, Jakarta.
Irawan, S., Tacconi, L. & Ring, I. (2013) Stakeholders’ incentives for
land-use change and REDD+: the case of Indonesia. Ecological Eco-
nomics, 87, 75–83.Kearney, J. (2010) Food consumption trends and drivers. Philosophical
Transactions of the Royal Society B Biological Sciences, 365, 2793–2807.Koh, L.P. & Ghazoul, J. (2010a) A matrix-calibrated species-area model
for predicting biodiversity losses due to land-use change. Conservation
Biology, 24, 994–1001.Koh, L.P. & Ghazoul, J. (2010b) A spatially-explicit scenario analysis for
reconciling agricultural expansion, forest protection and carbon conser-
vation in Indonesia. Proceedings of the National Academy of Sciences of
the United States of America, 107, 11140–11144.Koh, L.P. & Wilcove, D.S. (2007) Cashing in palm oil for conservation.
Nature, 448, 993–994.Koh, L.P., Miettinen, J., Liew, S.C. & Ghazoul, J. (2011) Remotely sensed
evidence of tropical peatland conversion to oil palm. Proceedings of the
National Academy of Sciences of the United States of America, 108,
5127–5132.Lee, J.S.H., Abood, S., Ghazoul, J., Barus, B., Obidzinski, K. & Koh, L.P.
(2013a) Environmental impacts of large-scale oil palm enterprises exceed
that of smallholdings in Indonesia. Conservation Letters, 7, 25–33.Lee, J.S.H., Ghazoul, J., Obidzinski, K. & Koh, L. (2013b) Oil palm
smallholder yields and incomes constrained by harvesting practices and
type of smallholder management in Indonesia. Agronomy for Sustainable
Development, 34, 501–513.Li, T.M. (2011) Centering labor in the land grab debate. The Journal of
Peasant Studies, 38, 281–298.McCarthy, J.F. (2010) Processes of inclusion and adverse incorporation:
oil palm and agrarian change in Sumatra, Indonesia. The Journal of
Peasant Studies, 37, 821–850.
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
10 J. S. H. Lee et al.
McCarthy, J.F., Gillespie, P. & Zen, Z. (2012) Swimming upstream: local
indonesian production networks in “globalized” palm oil production.
World Development, 40, 555–569.McCarthy, J.F., Vel, J.A.C. & Afiff, S. (2012) Trajectories of land acquisi-
tion and enclosure: development schemes, virtual land grabs, and green
acquisitions in Indonesia’s Outer Islands. The Journal of Peasant
Studies, 39, 521–549.Moore, S., Evans, C.D., Page, S.E., Garnett, M.H., Jones, T.G., Freeman,
C. et al. (2013) Deep instability of deforested tropical peatlands revealed
by fluvial organic carbon fluxes. Nature, 493, 660–663.Nantha, H.S. & Tisdell, C. (2009) The orangutan-oil palm conflict: eco-
nomic constraints and opportunities for conservation. Biodiversity and
Conservation, 18, 487–502.OECD (2012) OECD Review of Agricultural Policies: Indonesia 2012.
OECD Publishing.
Page, S.E., Morrison, R., Malins, C., Hooijer, A., Rieley, J.O. & Jauhiai-
nen, J. (2011) Review of Peat Surface Greenhouse Gas Emissions from
Oil Palm Plantations in Southeast Asia. The International Council on
Clean Transportation, Washington, DC. pp. 1–80.Perfecto, I. & Vandermeer, J. (2008) Biodiversity conservation in tropical
agroecosystems - A new conservation paradigm. Annals of the New York
Academy of Sciences, 1134, 173–200.Phalan, B., Fitzherbert, E.B., Rafflegeau, S., Struebig, M.J. & Verwilghen,
A. (2009) Conservation in oil-palm landscapes. Conservation Biology,
23, 244–245.Phalan, B., Balmford, A., Green, R.E. & Scharlemann, J.P.W. (2011a)
Minimising the harm to biodiversity of producing more food globally.
Food Policy, 36 Suppl 1, S62–S71.Phalan, B., Onial, M., Balmford, A. & Green, R.E. (2011b) Reconciling
food production and biodiversity conservation: land sharing and land
sparing compared. Science, 333, 1289–1291.Phalan, B., Bertzky, M., Butchart, S.H.M., Donald, P.F., Scharlemann,
J.P.W., Stattersfield, A.J. & Balmford, A. (2013) Crop expansion and
conservation priorities in tropical countries. PLoS ONE, 8, e51759.
Phelps, J., Carrasco, L.R., Webb, E.L., Koh, L.P. & Pascual, U. (2013)
Agricultural intensification escalates future conservation costs. Proceed-
ings of the National Academy of Sciences, doi:10.1073/pnas.1220070110.
R Development Core Team, (2008) R: A Language and Environment for
Statistical Computing. R Foundation for Statistica Computing, Vienna,
Austria.
Rist, L., Feintrenie, L. & Levang, P. (2010) The livelihood impacts of oil
palm: smallholders in Indonesia. Biodiversity and Conservation, 19,
1009–1024.Sandker, M., Suwarno, A. & Campbell, B.M. (2007) Will forests remain in
the face of oil palm expansion? Simulating change in Malinau, Indonesia
Ecology and Society, 12, 37 (http://www.ecologyandsociety.org/vol12/
iss2/art37/)
Sayer, J., Ghazoul, J., Nelson, P. & Klintuni Boedhihartono, A. (2012) Oil
palm expansion transforms tropical landscapes and livelihoods. Global
Food Security, 1, 114–119.Sheil, D., Casson, A., Meijaard, E., Noordwijk, M.v., Gaskell, J., Sunder-
land-Groves, J., Wertz, K. & Kanninen, M. (2009) The impacts and
opportunities of oil palm in Southeast Asia: What do we know and what
do we need to know? Occasional paper no. 51. CIFOR, Bogor, Indonesia.
Skinner, E.B. (2013) Indonesia’s Palm Oil Industry Rife with Human
Rights Abuses. Bloomberg Business week. (http://www.businessweek.
com/articles/2013-07-18/indonesias-palm-oil-industry-rife-with-human-
rights-abuses#p1) [Accessed on 21 November 2013].
Suharto, R. (2009) Sustainable production in Indonesia. China Interna-
tional Oil and Oilseeds Summit 2009. 8-10 July 2009, Beijing, China.
Suparno, R. & Afrida, N. (2009) RI to expand oil palm estates amid envi-
ronmental concerns. The Jakarta Post. (http://www.thejakartapost.com/
news/2009/12/03/ri-expand-oil-palm-estates-amid-environmental-concerns.
html) [Accessed on 21 November 2013]
Susanti, A. & Burgers, P. (2012) Oil palm expansion in Riau province,
Indonesia: Serving People, Planet, Profit? European Report on Develop-
ment. Utrecht University.
Tilman, D., Socolow, R., Foley, J.A., Hill, J., Larson, E., Lynd, L. et al.
(2009) Beneficial biofuels-the food, energy, and environment trilemma.
Science, 325, 270–271.Tscharntke, T., Clough, Y., Wanger, T.C., Jackson, L., Motzke, I.,
Perfecto, I., Vandermeer, J. & Whitbread, A. (2012) Global food secu-
rity, biodiversity conservation and the future of agricultural intensifica-
tion. Biological Conservation, 151, 53–59.
UNDP (2012) Indonesia Sustainable Palm Oil Initiative. United Nations
Development Program, Green Commodities Facility.
Vermeulen, S. & Goad, N. (2006) Towards better practice in small-
holder palm oil production. Natural Resources Issues Series No. 5.
International Institute for Environment and Development, London,
UK.
Wicke, B., Sikkema, R., Dornburg, V. & Faaij, A. (2011) Exploring land
use changes and the role of palm oil production in Indonesia and
Malaysia. Land Use Policy, 28, 193–206.Widjaja, F.O. (2012) A New Vision for Sustainable Agriculture. Interna-
tional Conference on Oil Palm and the Environment 2012. Bali,
Indonesia.
World Bank (2011) The World Bank Group Framework and IFC Strategy
for Engagement in the Palm Oil Sector. International Finance Corpora-
tion, Washington DC, USA. pp. 91.
WWI (2007) Biofuels for Transport: Global Potential and Implications for
Sustainable Energy and Agriculture. Worldwatch Institute, Earthscan,
U.K.
Yulisman, L. (2011) Empowering smallholders ‘key to output’. The
Jakarta Post. (http://www.thejakartapost.com/news/2011/05/12/empow-
ering-smallholders-%E2%80%98key-output%E2%80%99.html) [Acces-
sed on 30 November 2012].
Zen, Z., Barlow, C. & Gondowarsito, R. (2006) Oil Palm in Indonesian
Socio-Economic Improvement A Review of Options. Working Paper in
Trade and Economics 11. Economics,. Research School of Pacific and
Asian Studies, Australian National University.
Zen, Z., McCarthy, J.F. & Gillespie, P. (2008) Linking pro-poor policy
and oil palm cultivation. Crawford School of Economics and Govern-
ment at the Australian National University.
Received 17 December 2013; accepted 7 May 2014
Handling Editor: Julia Jones
Supporting Information
Additional Supporting Information may be found in the online version
of this article.
Appendix S1. Supplementary methods and supporting informa-
tion.
Table S1. Projected CPO production from 2010 to 2014 from each
island.
Table S2. Reported yield (tFFB ha�1 y�1) of independent small-
holders (Ind), scheme smallholders (Sch), and industrial estates
(Est) from published literature.
Table S3. Yield factors for oil palm production based on Fischer
et al. (2001).
Table S4. Assigning values to conversion priority indices for each
attribute i) proximity to oil palm mills (Imill), ii) proximity to road
networks (Iroad), iii) proximity to shipping ports (Iport), iv)
proximity to cities and main towns (Itown), v) land contiguity for
oil palm (Icontiguity), and vi) oil palm yield suitability (Iyield), to
derive conversion priority indices of a grid cell being converted into
an independent smallholding (Pids) and an industrial estate or
scheme smallholding (Pcps).
Table S5. Nitrogen fertilizer usage in different oil palm plantations.
Low and high estimates are calculated using the standard devia-
tion.
Table S6. Road development under different oil palm plantations.
Low and high estimates are calculated using the standard deviation.
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
Simulating oil palm expansion in Sumatra 11
Table S7. Public revenues generated (USD ha�1) at different
government levels from oil palm plantation development without
logging.
Table S8. Projected area of oil palm expansion under mean, low
and high estimates of relative yields for independent and scheme
smallholdings.
Table S9. Mean (� SD) values of outcome variables for land cover
converted to oil palm averaged over 10 000 runs from our
computer model simulation.
Table S10. Mean (� SD) values of environmental outcomes
averaged over 10 000 runs from our computer model simulation.
Table S11. Mean (� SD) values of outcome variables for socio-
economic outcomes averaged over 10 000 runs from our computer
model simulation.
Fig. S1. Spatial data used to parameterize the model. Our input
parameters include (a) distance to oil palm mills, (b) distance to
shipping ports, (c) distance to roads, (d) distance to towns, (e) yield
suitability for oil palm cultivation and (f) land contiguity for large-
scale oil palm expansion.
Fig. S2. Percentage difference between projected area of total oil
palm expansion using mean estimates of relative yields and using
low and high estimates of relative yields derived under Table S2.
© 2014 The Authors. Journal of Applied Ecology © 2014 British Ecological Society, Journal of Applied Ecology
12 J. S. H. Lee et al.