Large-scale Oil Palm Plantations Research Articles

Towards a sustainable business model for rubber agroforestry in Indonesia

Agroforestry systems, particularly rubber agroforests, are crucial for Dayak communities in Indonesia, providing economic benefits and vital assets for their livelihoods. Two common types in Simpang Dua sub-district are tembawang (traditional fruit gardens) and rubber agroforests. Both have flourished for generations but they now face threats of conversion due to declining rubber prices and the oil palm boom. Tembawang is considered more resilient due to better protection of tenure rights under local customary law and its greater provision of socioeconomic benefits. In some instances, rubber agroforests are only maintained because of their deep rooted social and cultural importance, but they have potential to still be economically valuable. Rubber agroforests can provide a diversified income, offering resilience against volatile rubber markets, and although oil palm provides higher income in the short term, rubber agroforests can provide higher income over the entire system cycle. Long-term financing is essential to improve yields and product quality, to support smallholder rubber agroforests, but obtaining this type of financing is difficult. Obstacles include low rubber prices, poor-quality latex, a lack of productivity of agroforestry crops and low attention from investors, financiers, and markets. Non-commercial financial support, including technical support, could help strengthen farming practices and market-based instruments, including carbon payments, could help stabilise farmers' income. The expansion, however, of large-scale oil palm plantations has shifted the rural labour force from rubber smallholders to plantation workers. Efforts to address these challenges include the establishment of a rubber processing and collective marketing unit, UPPB, to improve market access and prices for smallholder farmers. Founded in 2022, the unit aims to arrange collective marketing and provide technical capacity for farmers to meet the specifications of Standard Indonesia Rubber. By aggregating rubber slabs, farmers can earn up to 25% higher prices than individual farmers, but irregular supplies from farmers and low prices are affecting their success. Despite facing challenges, local farmers' groups remain resilient in organising themselves to improve their systems with the support of NGOs. Commitment from government and private sector stakeholders is additionally needed to further promote sustainable and inclusive rubber agroforestry businesses.

Analysis Of The Implementation Of Corporate Social And Environmental Responsibility In Kembang Janggut District East Kalimantan

PT. REA Kaltim Plantations is a large-scale oil palm plantation company in Kembang Janggut District, East Kalimantan. This research aims to analyze the implementation of social and environmental responsibility (TJSL) by companies, with a focus on environmental aspects. The problem formulation in this research is how to implement social and environmental responsibility (TJSL) at PT. REA Kaltim Plantations which is environmentally based and what obstacles the company faces in TJSL at PT. REA Kaltim Plantations in its implementation. This research uses empirical research methods using a qualitative approach. The results of research and discussions show that the company has implemented programs related to TJSL, but the achievements are considered not optimal. Some notes of improvement include, among others, the effectiveness of the program in empowering communities, reporting transparency, and active participation in building local sustainability. Companies also face challenges such as the complexity of community needs and environmental dynamics. The conclusion of this research is that companies need to improve TJSL implementation in order to make a greater contribution to sustainable development and welfare of local communities. Recommendations are given to improve the quality and sustainability of the TJSL program by the company.

Large contribution of soil N2O emission to the global warming potential of a large-scale oil palm plantation despite changing from conventional to reduced management practices

Abstract. Conventional management of oil palm plantations, involving high fertilization rate and herbicide application, results in high yield but with large soil greenhouse gas (GHG) emissions. This study aimed to assess a practical alternative to conventional management, namely reduced fertilization with mechanical weeding, to decrease soil GHG emissions without sacrificing production. We established a full factorial experiment with two fertilization rates (conventional and reduced fertilization, equal to nutrients exported via fruit harvest) and two weeding methods (herbicide and mechanical), each with four replicate plots, since 2016 in a ≥ 15-year-old, large-scale oil palm plantation in Indonesia. Soil CO2, N2O, and CH4 fluxes were measured during 2019–2020, and yield was measured during 2017–2020. Fresh fruit yield (30 ± 1 Mgha-1yr-1) and soil GHG fluxes did not differ among treatments (P≥ 0.11), implying legacy effects of over a decade of conventional management prior to the start of the experiment. Annual soil GHG fluxes were 5.5 ± 0.2 Mg CO2-C ha−1 yr−1, 3.6 ± 0.7 kg N2O-N ha−1 yr−1, and −1.5 ± 0.1 kg CH4-C ha−1 yr−1 across treatments. The palm circle, where fertilizers are commonly applied, covered 18 % of the plantation area but accounted for 79 % of soil N2O emission. The net primary production of this oil palm plantation was 17 150 ± 260 kgCha-1yr-1, but 62 % of this was removed by fruit harvest. The global warming potential of this planation was 3010 ± 750 kgCO2eqha-1yr-1, of which 55 % was contributed by soil N2O emission and only < 2 % offset by the soil CH4 sink.

Hibernation of the Village Law in Large-Scale Palm Oil Plantations: A Case Study of Oil Palm Expansion in Sintang District, West Kalimantan

This paper seeks to present the results of testing the implementation of the Village Law in villages covered by large-scale oil palm plantations. The socio-economic and political dynamics of villages with oil palm are in stark contrast to villages that are relatively free from the circle of the plantation capitalist system. This research examines it by focusing on the study of customary land acquisition practices and partnerships between smallholders and oil palm plantation companies in the Sintang District. Qualitative research using a case study approach which is the basis for writing this paper found that the Village Law, which many people hoped would free villages from the threats of the industrialization of forests and oil palm plantations, in fact, could not do much or, in the author's language, the Village Law was in hibernation.

The Effects of Peat Swamp Forest Patches and Riparian Areas within Large Scale Oil Palm Plantations on Bird Species Richness.

It is well established that oil palm is one of the most efficient and productive oil crops. However, oil palm agriculture is also one of the threats to tropical biodiversity. This study aims to investigate how set-aside areas in an oil palm plantation affect bird biodiversity. The research area includes two set-asides areas: peat swamp forest and riparian reserves and two oil palm sites adjacent to reserved forest sites. A total of 3,074 birds comprising 100 species from 34 families were observed in an oil palm plantation landscape on peatland located in the northern part of Borneo, Sarawak, Malaysia. Results showed that efforts by set-asides forest areas in large scale of oil palm dominated landscapes supported distinct bird species richness. High percentage of the canopies and shrub covers had a positive effect on bird species richness at area between oil palm and peat swamp forest. Herbaceous cover with height less than 1 m influenced the abundance of birds in the plantation closed to the peat swamp forest. The set-aside areas in oil palm plantations are essential in supporting bird's refuges and should be part of oil palm landscape management to improve biodiversity conservation. Thus, provided the forest set-aside areas are large enough and risks to biodiversity and habitat are successfully managed, oil palm can play an important role in biodiversity conservation.

Tree identity and canopy openness mediate oil palm biodiversity enrichment effects on insect herbivory and pollination.

As the extent of oil palm (Elaeis guineensis) cultivation has expanded at the expense of tropical rainforests, enriching conventional large-scale oil palm plantations with native trees has been proposed as a strategy for restoring biodiversity and ecosystem function. However, how tree enrichment affects insect-mediated ecosystem functions is unknown. We investigated impacts on insect herbivory and pollination in the fourth year of a plantation-scale, long-term oil palm biodiversity enrichment experiment in Jambi, Sumatra, Indonesia. Within 48 plots systematically varying in size (25-1600 m2 ) and planted tree species richness (one to six species), we collected response data on vegetation structure, understory insect abundances, and pollinator and herbivore activity on chili plants (Capsicum annuum), which served as indicators of insect-mediated ecosystem functions. We examined the independent effects of plot size, tree species richness, and tree identity on these response variables, using the linear model for random partitions design. The experimental treatments were most associated with vegetation structure: tree identity mattered, as the species Peronema canescens strongly decreased (by approximately one standard deviation) both canopy openness and understory vegetation cover; whereas tree richness only decreased understory flower density. Further, the smallest plots had the lowest understory flower density and richness, presumably because of lower light availability and colonization rates, respectively. Enrichment influenced herbivorous insects and natural enemies in the understory to a lesser extent: both groups had higher abundances in plots with two enrichment species planted, possibly because higher associated tree mortality created more habitat, while herbivores decreased with increasing tree species richness, in line with the resource concentration hypothesis. Linking relationships in structural equation models showed that the negative association between P. canescens and understory vegetation cover was mediated through canopy openness. Likewise, canopy openness mediated increases in herbivore and pollinator insect abundances. Higher pollinator visitation increased phytometer yield, while impacts of insect herbivores on yield were not apparent. Our results demonstrate that even at an early stage, different levels of ecological restoration influence insect-mediated ecosystem functions, mainly through canopy openness. These findings suggest that maintaining some canopy gaps while enrichment plots develop may be beneficial for increasing habitat heterogeneity and insect-mediated ecosystem functions.

Population status of the critically endangered tree Vatica venulosa (Dipterocarpaceae) in lowland riparian forests of East Kalimantan

Vatica venulosa is a threatened tree from the family Dipterocarpaceae. Due to degradation and conversion of its habitat in lowland riparian forests, this species is classified as Critically Endangered by the International Union for Conservation of Nature (IUCN) Red List. We carried out surveys for V. venulosa in Kutai Kartanegara, East Kalimantan, to depict the current population status of the species in the region. We surveyed 14 forested areas along Belayan River in Kutai Kartanegara. From these 14 locations, we only successfully identified V. venulosa at one location, namely in Long Beleh Village, Kembang Janggut District. A total of 71 individuals of which 84.5% classified in the 0-5 cm diameter class, were found. We also found nine individuals in the mature stage, i.e., producing flowers and fruits. The main threat to V. venulosa is habitat conversion into large-scale oil palm plantations. Protection of the forest fragment in Long Beleh is highly recommended in order to protect the species from local extinction.

Slowing deforestation in Indonesia follows declining oil palm expansion and lower oil prices

Much concern about tropical deforestation focuses on oil palm plantations, but their impacts remain poorly quantified. Using nation-wide interpretation of satellite imagery, and sample-based error calibration, we estimated the impact of large-scale (industrial) and smallholder oil palm plantations on natural old-growth ("primary") forests from 2001 to 2019 in Indonesia, the world's largest palm oil producer. Over nineteen years, the area mapped under oil palm doubled, reaching 16.24 Mha in 2019 (64% industrial; 36% smallholder), more than the official estimates of 14.72 Mha. The forest area declined by 11% (9.79 Mha), including 32% (3.09 Mha) ultimately converted into oil palm, and 29% (2.85 Mha) cleared and converted in the same year. Industrial plantations replaced more forest than detected smallholder plantings (2.13 Mha vs 0.72 Mha). New plantations peaked in 2009 and 2012 and declined thereafter. Expansion of industrial plantations and forest loss were correlated with palm oil prices. A price decline of 1% was associated with a 1.08% decrease in new industrial plantations and with a 0.68% decrease of forest loss. Deforestation fell below pre-2004 levels in 2017-2019 providing an opportunity to focus on sustainable management. As the price of palm oil has doubled since the start of the COVID-19 pandemic, effective regulation is key to minimising future forest conversion.

Early Effects of Fertilizer and Herbicide Reduction on Root-Associated Biota in Oil Palm Plantations

To secure high yield, tropical oil palm plantations are fertilized, and understory vegetation is controlled by chemical clearing with herbicides. These treatments cause a drastic turnover of soil microbes and cause loss of beneficial mycorrhizal fungi. Here, we tested if reduced fertilization and weeding instead of conventional treatments restored beneficial ecological groups associated with roots. We conducted our study one year after the start of the reduced management in large-scale oil palm plantations. We hypothesized that reduced fertilizer application and weeding result in shifts of the root-associated species composition because changes in the management regimes affect belowground biomass and nutrients in soil and roots. Alternatively, we hypothesized that the legacy of massive soil fertilization and herbicide application preclude compositional shifts of root-associated biota within short time periods. We did not find any significant treatment effects on root nutrient contents, root biomass, and nutrients in soil. At the level of species (based on operational taxonomic units obtained by Illumina sequencing) or phyla, no significant effects of reduced management were observed. However, distinct functional groups showed early responses to the treatments: nematodes decreased in response to weeding; yeasts and ectomycorrhizal-multitrophic fungi increased under fertilizer treatments; arbuscular mycorrhizal fungi increased under fertilizer reduction. Since the responsive ecological groups were represented by low sequence abundances, their responses were masked by very high sequence abundances of saprotrophic and pathotrophic fungi. Thus, the composition of the whole root-associated community was unaffected by reduced management. In conclusion, our results show that changes in management regimes start to re-wire critical constituents of soil–plant food webs.

Developing sustainable and profitable solutions for peatland restoration

Over the past decades, a large area of peat swamp forests in Indonesia has been cleared of the original forest cover and developed as agricultural lands. Several important issues are associated with the clearing and drainage of peat forest areas, including loss of biodiversity, increased emission of Green House Gases (GHGs), and smoke/haze pollution. Moreover, the development of large-scale oil palm plantations did not always improve local livelihoods. We describe how the restoration of degraded peat areas through paludiculture and inclusive value chains development could result in sustainable livelihoods and climate-resilient peat areas in Indonesia. We illustrate this by describing business cases of seven valuable native peat swamp forest species which could provide income for local forest communities. An analysis of the sago value chain shows that sago cultivation has a positive contribution in providing economic benefits to all actors, including local farmers, although improvements could be made for better value sharing. Paludiculture has important environmental benefits in comparison to existing drainage-based peat cultivation systems. The combination of environmental and economic benefits is an important incentive to develop the paludiculture system further to improve current peat management systems and assist further peat restoration in Indonesia. The development and implementation of paludiculture systems, particularly species selection, should have more community participation to ensure the sustainable restoration of degraded peat areas.

Mulching with pruned fronds promotes the internal soil N cycling and soil fertility in a large-scale oil palm plantation

Intensive management practices in large-scale oil palm plantations can slow down nutrient cycling and alter other soil functions. Thus, there is a need to reduce management intensity without sacrificing productivity. The aim of our study was to investigate the effect of management practices on gross rates of soil N cycling and soil fertility. In Jambi province, Indonesia, we established a management experiment in a large-scale oil palm plantation to compare conventional practices (i.e. high fertilization rates and herbicide weeding) with reduced management intensity (i.e. reduced fertilization rates and mechanical weeding). Also, we compared the typical management zones characterizing large-scale plantations: palm circle, inter-row and frond-stacked area. After 1.5 years of this experiment, reduced and conventional management showed comparable gross soil N cycling rates; however, there were stark differences among management zones. The frond-stacked area had higher soil N cycling rates and soil fertility (high microbial biomass, extractable C, soil organic C, extractable organic N, total N and low bulk density) than inter-row and palm circle (all p ≤ 0.05). Microbial biomass was the main driver of the soil N cycle, attested by its high correlation with gross N-cycling rates (r = 0.93–0.95, p < 0.01). The correlations of microbial N with extractable C, extractable organic N, soil organic C and total N (r = 0.76–0.89, p < 0.01) suggest that microbial biomass was mainly regulated by the availability of organic matter. Mulching with senesced fronds enhanced soil microbial biomass, which promoted nutrient recycling and thereby can decrease dependency on chemical fertilizers.

Herbicide weed control increases nutrient leaching compared to mechanical weeding in a large-scale oil palm plantation

Abstract. Nutrient leaching in intensively managed oil palm plantations can diminish soil fertility and water quality. There is a need to reduce this environmental footprint without sacrificing yield. In a large-scale oil palm plantation in Acrisol soil, we quantified nutrient leaching using a full factorial experiment with two fertilization rates (260 kg N, 50 kg P, and 220 kg K ha−1 yr−1 as conventional practice and 136 kg N, 17 kg P, and 187 kg K ha−1 yr−1, equal to harvest export, as reduced management) and two weeding methods (conventional herbicide application and mechanical weeding as reduced management) replicated in four blocks. Over the course of 1 year, we collected monthly soil pore water at 1.5 m depth in three distinct management zones: palm circle, inter-row, and frond-stacked area. Nutrient leaching in the palm circle was low due to low solute concentrations and small drainage fluxes, probably resulting from large plant uptake. In contrast, nitrate and aluminum leaching losses were high in the inter-row due to the high concentrations and large drainage fluxes, possibly resulting from low plant uptake and low pH. In the frond-stacked area, base cation leaching was high, presumably from frond litter decomposition, but N leaching was low. Mechanical weeding reduced leaching losses of base cations compared to the conventional herbicide weeding probably because herbicides decreased ground vegetation and thus reduced soil nutrient retention. Reduced fertilization rates diminished the nitrate leaching losses. Leaching of total nitrogen in the mechanical weeding with reduced fertilization treatment (32±6 kg N ha−1 yr−1) was less than half of the conventional management (74±20 kg N ha−1 yr−1), whereas yields were not affected by these treatments. Our findings suggest that mechanical weeding and reduced fertilization should be included in the program by the Indonesian Ministry of Agriculture for precision farming (e.g., variable rates with plantation age), particularly for large-scale oil palm plantations. We further suggest including mechanical weeding and reduced fertilization in science-based policy recommendations, such as those endorsed by the Roundtable for Sustainable Palm Oil association.

Studying the Impacts of Land Use Changes on the Occurrence of Vector Mosquitoes in Sabah, Malaysia

Land use changes as a result of infrastructural and agricultural development such as construction of forest field centre, establishment of large-scale oil palm plantations, and logging activities are increasing in Malaysia. These activities lead to environmental disturbances and may affect the ecological balance of many organisms. Mosquitoes are very sensitive to environmental changes since their diversity, distribution and abundance are influenced by even small changes in environmental conditions such as availability of suitable breeding sites. Mosquitoes from three different sites of varying disturbance levels at the SAFE Project experimental areas in eastern Sabah i.e., old growth forest (OG), logged forest (LFE) and heavily logged forest (Block B) were collected and identified to species level. Shannon-Wiener index and Simpson index of diversity were calculated and the diversity value were highest in LFE (H’= 0.4434, 1/D= 1.3427) and the least in Block B (H’= 0.3260, 1/D= 1.1627). A similar trend was detected in terms of mosquito abundance with the highest abundance recorded in LFE and the least in Block B. Results of the present study generally suggest that land use changes do affect mosquito diversity and abundance by altering, creating or providing places for the adult mosquitoes to breed.

Cross-regional oil palm tree counting and detection via a multi-level attention domain adaptation network

Providing an accurate evaluation of palm tree plantation in a large region can bring meaningful impacts in both economic and ecological aspects. However, the enormous spatial scale and the variety of geological features across regions has made it a grand challenge with limited solutions based on manual human monitoring efforts. Although deep learning based algorithms have demonstrated potential in forming an automated approach in recent years, the labelling efforts needed for covering different features in different regions largely constrain its effectiveness in large-scale problems. In this paper, we propose a novel domain adaptive oil palm tree detection method, i.e., a Multi-level Attention Domain Adaptation Network (MADAN) to reap cross-regional oil palm tree counting and detection. MADAN consists of 4 procedures: First, we adopted a batch-instance normalization network (BIN) based feature extractor for improving the generalization ability of the model, integrating batch normalization and instance normalization. Second, we embedded a multi-level attention mechanism (MLA) into our architecture for enhancing the transferability, including a feature level attention and an entropy level attention. Then we designed a minimum entropy regularization (MER) to increase the confidence of the classifier predictions through assigning the entropy level attention value to the entropy penalty. Finally, we employed a sliding window-based prediction and an IOU based post-processing approach to attain the final detection results. We conducted comprehensive ablation experiments using three different satellite images of large-scale oil palm plantation area with six transfer tasks. MADAN improves the detection accuracy by 14.98% in terms of average F1-score compared with the Baseline method (without DA), and performs 3.55–14.49% better than existing domain adaptation methods. Experimental results demonstrate the great potential of our MADAN for large-scale and cross-regional oil palm tree counting and detection, guaranteeing a high detection accuracy as well as saving the manual annotation efforts.

In Vitro Wound Healing Potential of Flavonoid C-Glycosides from Oil Palm (Elaeis guineensis Jacq.) Leaves on 3T3 Fibroblast Cells.

Oil palm (Elaeis guineensis Jacq.) leaves (OPL) are widely available at zero cost in Southeast Asia countries, especially in Malaysia and Indonesia due to large scale oil palm plantations. OPLs contain a large amount of flavonoids in particular flavonoid C-glycosides, which are known to possess useful biological properties including antioxidant and wound healing properties. The present study aimed at evaluating the wound healing efficacy of OPL in various solvent extracts and flavonoid enriched fractions and to determine the contribution of flavonoid C-glycosides (orientin, isoorientin, vitexin and isovitexin) using in-vitro scratch assay on 3T3 fibroblast cells. Solvent crude extracts with different polarity were screened and the most active extract was subjected to acid hydrolysis. The crude and acid hydrolysed extracts were further enriched using macroporous resins, XAD7HP. UHPLC-UV/PDA and LC-MS/MS analysis were applied for identification and confirmation of flavonoid C-glycosides. The wound healing properties comprised of cell viability, cell proliferation and cell migration were studied. Allantoin was used as a positive control to compare the efficacy among the tested samples. The results revealed all OPL crude extracts, flavonoid enriched fractions and flavonoid C-glycosides were non-toxic at concentrations below 25 µg/mL and showed better cell proliferation and migration activities at low concentrations than higher concentrations.. This study also demonstrated orientin, isoorientin, vitexin and isovitexin presented in OPL extracts and flavonoid enriched fractions stimulated proliferation and migration of 3T3 fibroblast cells. Hence, these findings may pose potential therapeutic bioactive agents for wound healing by enhancing fibroblast proliferation and migration.

A case study on the impacts of oil palm plantation on butterflies: differences in plantation scale and management implications

Changes in land use to oil palm plantations have an impact on the biodiversity of tropical butterflies known to have species with a wide ecological range. We research to determine the impact of oil palm plantations on the diversity of butterfly species on two different plantation scales (large scale and small scale of plantation). The results showed that both of the oil palm plantations equally affected the increase in the number and level of species diversity of butterflies as many as 100 - 366% on large-scale oil palm plantations and by 0 - 466% on small-scale oil palm plantation. The development of oil palm plantations also has an impact on changes in species composition which is reflected in the level of similarity in species which is quite low, namely 0 - 0.22 in large oil palm plantations and 0.12 - 0.20 in small-scale plantations. The percentage of species loss in both types of plantations is the same, namely 60%, but there is greater species gain on small-scale oil palm plantations (60 - 400%) than large-scale (166 - 366%). Plantation management that creates habitat heterogeneity can increase the level of butterfly biodiversity on both plantations.

Understanding local perceptions of the impacts of large-scale oil palm plantations on ecosystem services in the Brazilian Amazon

Despite the increasing research on the impacts of oil palm, few studies have examined local perceptions of environmental changes of large-scale plantations in Latin America. This paper addresses this research gap through focusing on understanding these perceptions in communities bordering two plantations with different time of exposure to land use transformation in the Amazonian state of Pará, Brazil. Drawing on the concept of ecosystem services, results from our survey and qualitative interviews indicate that water availa bility, air and water quality were perceived to be the most heavily impacted ecosystem services by this crop. While respondents were aware of the negative impacts on ecosystem services of future palm plantations in the two sites, the majority tend to support a future expansion of this crop. Demographic characteristics as well as time of exposure to the crop did not correlate with peoples' perceptions as people in both sites tended to privilege job opportunities and economic benefits. We found that people's perceptions of land use change trade-offs were also linked to wider economic and social sustainability issues such as land conflicts, agribusiness management practices and distinct oil palm trajectories. We suggest that information on stakeholders' interactions, social differentiation and social and economic sustainability is needed for policy design and planning to complement an ecosystem services analysis of the trade-offs of oil palm expansion.

Birds associated with different tree species and structures in oil palm agroforestry landscapes in Malaysia

ABSTRACTThe expansion of oil palm (Elaeis guineensis) cultivation has been recognised as a major threat to tropical biodiversity. Smallholdings, however, unlike large-scale conventional monoculture oil palm plantations, often practice polyculture which may resemble an agroforestry system. These private holdings provide more heterogeneous vegetation which may support greater a greater diversity of birds. This study compared species richness and abundance of birds detected perching in oil palm (both dead and living trees) and seven other planted crop species within oil palm smallholdings. Using transect line surveys, we recorded a total of 816 birds of 39 species from 20 families. Our results indicate that bird species richness and abundance differed significantly between oil palm and the other planted tree species. Non-oil palm trees cumulatively increased bird species richness and abundance. Although birds overall perched more frequently on living oil palm trees (probably reflecting relative abundance), other species including breadfruit, mango, papaya, banana, and coconut, as well as dead trees, were also used. By measuring effect size, we also found that both bird species richness and abundance rely on tree structure and type of tree species. These findings tentatively suggest that providing a larger diversity of tree species within intensively managed oil palm plantations may support a wider variety of local bird species compared to monocultures.

Policy advocation: the potential role of independent smallholding oil palm plantation in biodiversity conservation

Despite the frequent reports of large-scale oil palm plantations’ lack of attention to biodiversity conservation, there is a paucity of reporting on smallholding plantation contributions in this regard. Yet, vegetation heterogeneity supports richer biodiversity, and this is a characteristic of independent smallholdings. This paper discusses the potential role of independent smallholding oil palm plantations in biodiversity conservation with respect to butterfly and earthworms. Data were collected on four large-scale and four smallholding plantations in the Districts of Kampar, Pelalawan, Kuantan, Singingi and Siak of Riau Province, using a time-survey method for butterflies and hand-sorting method for earthworms. The research also used direct interview with oil palm owners and community members to assess the environmental value of independent smallholdings. Results showed that independent smallholdings were considered to be ecologically-friendly, where most have been shown to support higher species richness of butterfly and higher density of earthworms, than large-scale plantations, due to the irregular maintenance practices, as well as proximity to secondary forest and rubber plantations. It can be concluded that the informed management of independent smallholding oil palm plantations could effectively support biodiversity conservation.

Discriminating between large-scale oil palm plantations and smallholdings on tropical peatlands using vegetation indices and supervised classification of LANDSAT-8

ABSTRACTTropical peat swamp forest is rapidly being converted into industrial-scale oil palm agriculture across South-east Asia. This has global and local environmental implications including habitat loss and carbon release. Monitoring oil palm expansion or land-use/land-cover on peatlands is feasible using remote sensing technology, however, there are few examples of assessments of different oil palm management systems. Three peatland land cover types were assessed and mapped using vegetation indices and supervised classifications of Landsat-8 level-2 imagery: peat swamp forest, large-scale oil palm plantation and smallholding. Firstly, we calculated and compared differences in vegetation indices (NDVI, EVI and SAVI) values between each of the land covers. Next, we mapped land cover using three classification methods – Support Vector Machine, Random Trees and Maximum Likelihood – with a single date and multi-temporal datasets. These were applied to the vegetation indices and also a three band Landsat image using band 2 (blue band), band 4 (red band) and band 5 (near-infrared band) i.e. false colour composite. The vegetation index assessment found significant differences in the NDVI, EVI and SAVI between peat swamp forest, large-scale plantation and smallholding. The NDVI in peat swamp forest was highest. In contrast, the EVI and SAVI in the peat swamp forest were the lowest. While the NDVI, EVI and SAVI in the large-scale plantations were greater than the smallholdings. Irrespective of landscape type, there were strong positive correlations between NDVI and EVI, NDVI and SAVI, and EVI and SAVI. For the land cover mapping, the best classifier was Random Trees with the multi-temporal Landsat bands 543 datasets with a mapping accuracy of 95.54% and a Kappa coefficient of 0.933. This study demonstrated that both vegetation indices and land cover mapping can provide planners and decision-makers with tools to monitor natural and production landscapes, managed under different systems in the tropics.