A review of the ecosystem functions in oil palm plantations, using forests as a reference system

Exploring the intersection of digitalization and sustainability in oil palm production: challenges, opportunities, and future research agenda

The increasing global demand for palm oil and its derivatives has led to significant environmental and social concerns, prompting the need for sustainable practices in oil palm production. In recent years, digital technologies have emerged as a potential solution to enhance sustainability in this sector. The objective of this review was to provide insights into the potential benefits and limitations of digital technologies in promoting sustainable practices in the oil palm industry, and to identify key challenges that must be addressed to ensure that digitalization contributes to sustainable development in this sector. To obtain valuable insights on this topic, this review employed a thorough analysis and exploration of relevant literature. Our findings highlight the transformative potential of digital technologies such as precision agriculture, data analytics, blockchain, and robotics to optimize resource utilization, improving efficiency, promoting social welfare, improving supply chain transparency, mitigating environmental impacts, and enhancing sustainability in oil palm production. However, the adoption of these technologies is hindered by several challenges, including high cost, lack of knowledge, and inadequate infrastructure. Our findings emphasize the importance of supportive policies, collaborative efforts, and targeted research to promote technology adoption and ensure equitable benefits across the oil palm industry. Recommendations are provided for industry stakeholders, policymakers, and researchers to leverage digitalization effectively and promote sustainable practices in the oil palm industry, ultimately contributing to global sustainability goals.

Spatiotemporal analysis of seasonal trends in land surface temperature within the distribution range of Moringa peregrina (Forssk.) in Southern and Southeastern Iran

Temperature fluctuations and related factors are among the main causes of climate change. Understanding the temporal and spatial variations in temperature can shed light on how species respond to climate change. Plants generally persist in suitable microclimates in response to environmental change; however, examining long-term temperature variations within a species' range can be challenging using field observations. Thermal remote sensing, on the other hand, provides multi-scale time-series data with good coverage and regularity to overcome the challenges associated with field observations in environmental monitoring. Although changes in land surface temperature (LST) affect climate, hydrological processes, land-atmosphere interactions, and ecological activities, this metric has not received much research attention. This study aimed to analyze changes in habitat suitability and microclimatic conditions for Moringa peregrina. Seasonal changes in LST within the distribution range of the species were also investigated. To this aim, mean seasonal LST was computed in Google Earth Engine using the daily MODIS/006/MYD13A2 product from 2003 to 2023. Subsequently, a binary habitat suitability map was created based on the true skill statistic (TSS). The Mann-Kendall test was used to analyze seasonal LST trends. Major trends in LST were quantified based on the z-score, and compatibility with habitat suitability was evaluated via GAP analysis and the Kappa index. Seasonal temperature trends were evaluated by comparing each season with the following season using binary comparison. Landforms at presence points were regarded as microclimates and the sensitivity of microclimates to LST was evaluated using two methods: Principal component analysis (PCA) was used to quantify seasonal LST heterogeneity and the random forest (RF) approach was used to evaluate the effect of environmental parameters on habitat suitability within microclimates. The Kappa index revealed a weak overlapping between suitable / unsuitable habitat and the surfaces affected by the trend of changes. Moreover, the suitable habitat of Moringa peregrina in spring, autumn and winter is spatially overlapped by areas that have shown an increasing LST trend, and the presence points have not experienced an increasing temperature trend only in the summer. The findings show that the analysis of seasonal trends in LST provides insights into the effect of LST on habitat suitability and the condition of vegetation. The current study clearly shows that seasonal changes have had a significant impact on the distribution and habitat suitability of M. peregrina, particularly during summer and winter. Improved habitat suitability and range expansion were observed throughout the year. The study also highlights the role of landforms in regulating temperature. Landforms such as local ridges with minimal temperature fluctuations and regions near the Oman Sea were identified as potential future habitats due to favorable humidity conditions.

Modeling the impacts of oil palm plantations on water quantity and quality in the Kais River Watershed of Indonesia

Oil palm plantations can impact hydrological processes in many tropical watersheds. The rapid conversion of tropical rainforests for commercial operations in recent decades has been associated with water scarcity, flooding, and polluted rivers. However, this widespread and emerging issue is less studied and underreported due to limited data availability, modeling complexity, and the remote nature of these landscapes. Ecohydrologic modeling enables us to investigate changes in watershed conditions caused by large-scale land cover changes from plantations. This study examines the impact of oil plantations on water quantity and quality using the SWAT+ model in the Kais River Watershed, West Papua, Indonesia. The objective is to assess the hydrological changes concerning land cover conversion to oil palm plantations. Results show that establishing oil palm plantations increased surface runoff by 21 %, and sediment yields rose by 16.9 % compared to the baseline. There was also a significant increase of 78 % in mean annual total nitrogen and 144 % in total phosphorous after the plantations' establishment. The results show that forest conversion to oil palm plantations in the Kais River watershed is a primary driver of change in hydrological regimes, resulting in the deterioration of water quality. There is a need for conservation strategies to mitigate the impacts of significant landscape changes in watershed ecosystems.

The socioecological benefits and consequences of oil palm cultivation in its native range: The Sustainable Oil Palm in West Africa (SOPWA) Project

Agriculture is expanding rapidly across the tropics. While cultivation can boost socioeconomic conditions and food security, it also threatens native ecosystems. Oil palm (Elaeis guineensis), which is grown pantropically, is the most productive vegetable oil crop worldwide. The impacts of oil palm cultivation have been studied extensively in Southeast Asia and - to a lesser extent - in Latin America but, in comparison, very little is known about its impacts in Africa: oil palm's native range, and where cultivation is expanding rapidly. In this paper, we introduce a large-scale research programme - the Sustainable Oil Palm in West Africa (SOPWA) Project - that is evaluating the relative ecological impacts of oil palm cultivation under traditional (i.e., by local people) and industrial (i.e., by a large-scale corporation) management in Liberia. Our paper is twofold in focus. First, we use systematic mapping to appraise the literature on oil palm research in an African context, assessing the geographic and disciplinary focus of existing research. We found 757 publications occurring in 36 African countries. Studies tended to focus on the impacts of palm oil consumption on human health and wellbeing. We found no research that has evaluated the whole-ecosystem (i.e., multiple taxa and ecosystem functions) impacts of oil palm cultivation in Africa, a knowledge gap which the SOPWA Project directly addresses. Second, we describe the SOPWA Project's study design and-using canopy cover, ground vegetation cover, and soil temperature data as a case study-demonstrate its utility for assessing differences between areas of rainforest and oil palm agriculture. We outline the socioecological data collected by the SOPWA Project to date and describe the potential for future research, to encourage new collaborations and additional similar projects of its kind in West Africa. Increased research in Africa is needed urgently to understand the combined ecological and sociocultural impacts of oil palm and other agriculture in this unique region. This will help to ensure long-term sustainability of the oil palm industry-and, indeed, all tropical agricultural activity-in Africa.

Ornamental Phoenix palm trees as habitat for fauna in the Mediterranean Region - results from a full year monitoring

In the European Mediterranean Region, palm trees are a common element in cities and semi-urban landscapes and have become important habitat structures for local fauna. This study aimed to monitor the invertebrate and vertebrate fauna occurring on and associated with ornamental palms of the genus Phoenix, over the course of one year. Five study sites were used in southern Spain, with varying levels of management. Several complementary methods were applied monthly in order to assess the vertebrates and invertebrates associated with the full seasonal cycle of palms, including flowering and fruiting. The study resulted in the identification of 216 invertebrate families from seven different classes and 89 vertebrate species, consisting of 62 bird, 20 mammal (including bats), six reptile and one amphibian species associated with Phoenix palms. It thus highlights that Phoenix palms provide a habitat for many species and individuals over the course of one year.

Integrating forest restoration into land-use planning at large spatial scales

Forest restoration is being scaled up globally, carrying major expectations of environmental and societal benefits. Current discussions on ensuring the effectiveness of forest restoration are predominantly focused on the land under restoration per se. But this focus neglects the critical issue that land use and its drivers at larger spatial scales have strong implications for forest restoration outcomes, through the influence of landscape context and, importantly, potential off-site impacts of forest restoration that must be accounted for in measuring its effectiveness. To ensure intended restoration outcomes, it is crucial to integrate forest restoration into land-use planning at spatial scales large enough to account for - and address - these larger-scale influences, including the protection of existing native ecosystems. In this review, we highlight this thus-far neglected issue in conceptualizing forest restoration for the delivery of multiple desirable benefits regarding biodiversity and ecosystem services. We first make the case for the need to integrate forest restoration into large-scale land-use planning, by reviewing current evidence on the landscape-level influences and off-site impacts pertaining to forest restoration. We then discuss how science can guide the integration of forest restoration into large-scale land-use planning, by laying out key features of methodological frameworks required, reviewing the extent to which existing frameworks carry these features, and identifying methodological innovations needed to bridge the potential shortfall. Finally, we critically review the status of existing methods and data to identify future research efforts needed to advance these methodological innovations and, more broadly, the effective integration of forest restoration design into large-scale land-use planning.

Elucidating the daily foraging activity pattern of Oecophylla smaragdina to minimize bite nuisances in Asia large agro-system plantations

Oecophylla smaragdina F., the Asian weaver ant, is one of the oil palm plantation's (Elaeis guineensis) potential predators, for the invasive bagworm species Metisa plana Walker, but this ant is a nuisance species that irritates plantation workers with their sharp bites. Here we assess the foraging activities (FA) of O. smaragdina's major workers, identify its inactive times and the existence of supervision, a novelty for social insects. Between 2018 and 2022, the pattern of trunk foraging activity was used as a mitigation measure. The relationship between trunk FA and air temperature (AT), relative humidity (RH), air pressure (AP), and rainfall interception (RI) was also investigated. Our results showed that, O. smaragdina is a strictly diurnal ant species, has little to no crepuscular activity, and stopped foraging during darkness. Moreover, veteran bigger workers systematically acted as supervisors by monitoring trails, intercepting, and bringing back to nests smaller individuals during heat peaks. In relation to population size relative abundance, all colonies displayed greater intensity during the warmest daily periods with higher mean forager density among the bigger colony, regardless of the dry-rainy intervals corresponded to minimal activity from late scotophase to early photophase and showed a bimodal pattern. Thus, forager activity peaked between 1100-1530 h and 1745-1845 h, and an average two-fold daily sudden decrease in intensity between 1620 and 1650 h as a partial cut-off period (first report). Furthermore, foraging activity, AT, AP showed a significant positive correlation while RH was negative. Finally, we found that from the base palm trunks, defensive territorial layers extended to 5 m on average with different spatial configurations indicating greater foraging density within the first 2 m. Our study shows O. smaragdina daily low activity periods, before 1000 h, being the most suitable to avoid forager attacks to facilitate pruning and harvesting tasks.

Land-use change from market responses to oil palm intensification in Indonesia

Oil palm is a major driver of tropical deforestation. A key intervention proposed to reduce the footprint of oil palm is intensifying production to free up spare land for nature, yet the indirect land-use implications of intensification through market forces are poorly understood. We used a spatially explicit land-rent modeling framework to characterize the supply and demand of oil palm in Indonesia under multiple yield improvement and demand elasticity scenarios and explored how shifts in market equilibria alter projections of crop expansion. Oil palm supply was sensitive to crop prices and yield improvements. Across all our scenarios, intensification raised agricultural rents and lowered the effectiveness of reductions in crop expansion. Increased yields lowered oil palm prices, but these price-drops were not sufficient to prevent further cropland expansion from increased agricultural rents under a range of price elasticities of demand. Crucially, we found that agricultural intensification might only result in land being spared when the demand relationship was highly inelastic and crop prices were very low (i.e., a 70% price reduction). Under this scenario, the extent of land spared (∼0.32 million ha) was countered by the continued establishment of new plantations (∼1.04 million ha). Oil palm intensification in Indonesia could exacerbate current pressures on its imperiled biodiversity and should be deployed with stronger spatial planning and enforcement to prevent further cropland expansion.

Future Climate Effects on Yield and Mortality of Conventional versus Modified Oil Palm in SE Asia

Palm oil is a very important commodity which will be required well into the future. However, the consequences of growing oil palm (OP) are often detrimental to the environment and contribute to climate change. On the other hand, climate change stress will decrease the production of palm oil by causing mortality and ill health of OP, as well as reducing yields. Genetically modified OP (mOP) may be produced in the future to resist climate change stress, although it will take a long time to develop and introduce, if they are successfully produced at all. It is crucial to understand the benefits mOP may bring for resisting climate change and increasing the sustainability of the palm oil industry. This paper employs modeling of suitable climate for OP using the CLIMEX program in (a) Indonesia and Malaysia, which are the first and second largest growers of OP respectively, and (b) Thailand and Papua New Guinea, which are much smaller growers. It is useful to compare these countries in terms of future palm oil production and what benefits planting mOP may bring. Uniquely, narrative models are used in the current paper to determine how climate change will affect yields of conventional OP and mOP. The effect of climate change on the mortality of mOP is also determined for the first time. The gains from using mOP were moderate, but substantial, if compared to the current production of other continents or countries. This was especially the case for Indonesia and Malaysia. The development of mOP requires a realistic appreciation of what benefits may accrue.

Tree islands enhance biodiversity and functioning in oil palm landscapes

In the United Nations Decade on Ecosystem Restoration1, large knowledge gaps persist on how to increase biodiversity and ecosystem functioning in cash crop-dominated tropical landscapes2. Here, we present findings from a large-scale, 5-year ecosystem restoration experiment in an oil palm landscape enriched with 52 tree islands, encompassing assessments of ten indicators of biodiversity and 19 indicators of ecosystem functioning. Overall, indicators of biodiversity and ecosystem functioning, as well as multidiversity and ecosystem multifunctionality, were higher in tree islands compared to conventionally managed oil palm. Larger tree islands led to larger gains in multidiversity through changes in vegetation structure. Furthermore, tree enrichment did not decrease landscape-scale oil palm yield. Our results demonstrate that enriching oil palm-dominated landscapes with tree islands is a promising ecological restoration strategy, yet should not replace the protection of remaining forests.

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.

Smallholder oil palm plantation sustainability assessment using multi-criteria analysis and unmanned aerial vehicles

Oil palm agriculture has caused extensive land cover and land use changes that have adversely affected tropical landscapes and ecosystems. However, monitoring and assessment of oil palm plantation areas to support sustainable management is costly and labour-intensive. This study used an unmanned aerial vehicles (UAV) to map smallholder farms and applied multi-criteria analysis to data generated from orthomosaics, to provide a set of sustainability indicators for the farms. Images were acquired from a UAV, with structure from motion (SfM) photogrammetry then used to produce orthomosaics and digital elevation models of the farm areas. Some of the inherent problems using high spatial resolution imagery for land cover classification were overcome by using texture analysis and geographic object-based image analysis (OBIA). Six spatially explicit environmental metrics were developed using multi-criteria analysis and used to generate sustainability indicator layers from the UAV data. The SfM and OBIA approach provided an accurate, high-resolution (~5 cm) image-based reconstruction of smallholder farm landscapes, with an overall classification accuracy of 89%. The multi-criteria analysis highlighted areas with lower sustainability values, which should be considered targets for adoption of sustainable management practices. The results of this work suggest that UAVs are a cost-effective tool for sustainability assessments of oil palm plantations, but there remains the need to plan surveys and image processing workflows carefully. Future work can build on our proposed approach, including the use of additional and/or alternative indicators developed through consultation with the oil palm industry stakeholders, to support certification schemes such as the Roundtable on Sustainable Palm Oil (RSPO).

Synthesis of 12-aminododecenoic acid by coupling transaminase to oxylipin pathway enzymes

Biobased polymers derived from plant oils are sustainable alternatives to petro based polymers. In recent years, multienzyme cascades have been developed for the synthesis of biobased ω-aminocarboxylic acids, which serve as building blocks for polyamides. In this work, we have developed a novel enzyme cascade for the synthesis of 12-aminododeceneoic acid, a precursor for nylon-12, starting from linoleic acid. Seven bacterial ω-transaminases (ω-TAs) were cloned, expressed in Escherichia coli and successfully purified by affinity chromatography. Activity towards the oxylipin pathway intermediates hexanal and 12-oxododecenoic acid in their 9(Z) and 10(E) isoforms was demonstrated for all seven transaminases in a coupled photometric enzyme assay. The highest specific activities were obtained with ω-TA from Aquitalea denitrificans (TR_AD), with 0.62 U mg^-1 for 12-oxo-9(Z)-dodecenoic acid, 0.52 U mg^-1 for 12-oxo-10(E)-dodecenoic acid and 1.17 U mg^-1 for hexanal. A one-pot enzyme cascade was established with TR_AD and papaya hydroperoxide lyase (HPL_CP-N), reaching conversions of 59% according to LC-ELSD quantification. Starting from linoleic acid, up to 12% conversion to 12-aminododecenoic acid was achieved with a 3-enzyme cascade comprising soybean lipoxygenase (LOX-1), HPL_CP-N and TR_AD. Higher product concentrations were achieved by the consecutive addition of enzymes compared to simultaneous addition at the beginning. KEY POINTS: • Seven ω-transaminases converted 12-oxododecenoic acid into its corresponding amine. • A three-enzyme cascade with lipoxygenase, hydroperoxide lyase, and ω-transaminase was established for the first time. • A one-pot transformation of linoleic acid to 12-aminododecenoic acid, a precursor of nylon-12 was achieved.

Assessing the changes in river water quality across a land-use change (forest to oil palm plantation) in peninsular Malaysia using the stable isotopes of water and nitrate

Land conversion from natural forests to plantations (e.g., oil palm) in Southeast Asia is one of the most intensive land-use changes occurring worldwide. To clarify the effects of oil palm plantations on water quality, we conducted multipoint river and stream water sampling in peninsular Malaysia at the end of the rainy season over a 3-year period (2013-2015). We measured the major dissolved ions and stable isotope ratios of water (δ²H-H₂O and δ¹⁸O-H₂O) and nitrate (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) in water from the upper streams in mountainous forests to the midstream areas of two major rivers in peninsular Malaysia. The electrical conductivity increased, and the d-excess value (as an index of the degree of evaporation) decreased with increasing distance from the headwaters, suggesting the effect of evaporative enrichment and the addition of pollutants. We separated the sampling points into four groups (G1-G4) through cluster analysis of the water quality data. From the land use/land cover (LULC) classification maps developed from satellite images and local information, we found that G1 and G2 mainly consisted of sampling points in forested areas, while G3 and G4 were located in oil-palm-affected areas. The concentrations of major ions were higher in the oil palm areas, indicating the effects of fertilizer and limestone (i.e., pH adjustment) applications. The dissolved inorganic nitrogen concentration did not differ among the groups, but the dissolved organic carbon, total dissolved nitrogen, and δ¹⁵N-NO₃^- were higher in the oil palm area than in the forested area. Although the nitrogen concentration was low, even in the oil palm area, the significantly higher δ¹⁵N-NO₃^- in the oil palm area indicated substantial denitrification. This implies that denitrification contributed to the lowering of the NO₃^- concentration in rivers in the oil palm area, in addition to nutrient uptake by oil palm trees.

Climate Refuges in Nigeria for Oil Palm in Response to Future Climate and Fusarium Wilt Stresses

The detrimental stresses of future climate change are well known and decisions are required to reduce their effects. Climate and disease stresses cause severe damage to plants and it is essential to understand how they will respond. Oil palm (OP) is an Fusarium important crop for many countries. The palm originated in Africa, where palm oil is produced in the largest amount within the continent by Nigeria. OP becomes stressed by climate change and wilt, a devastating disease of OP in Africa. Previous methods to determine the suitability of future climate on OP in continents and whole countries were applied to Nigeria, which is the first time an individual country has been assessed in this manner. Climate maps of Nigeria were divided equally into 16 regions from north to south and east to west to determine the future suitable climate for growing OP. CLIMEX and narrative modelling were used to determine suitability for growing OP and Fusarium wilt incidence for current time and 2050. Maps from published papers were employed directly thereby facilitating the procedure. A distinct latitudinal increasing trend from north to south in suitable climate was observed, which was unexpected. A decreasing longitudinal trend from west to east was also observed. These differences in suitable climates may allow refuges for OP in the future. The growth of OP in the south of Nigeria may be largely unaffected by climate change by 2050, unlike the north. The procedures allow policy decisions at state and national levels to be made from empirical data, which do not otherwise exist. States with low amounts of OP and where the climate deteriorates greatly, could usefully be abandoned. Other low palm oil producers, where the climate does not deteriorate greatly, could be encouraged to develop OP. Little requires to be done in the high producing states where the climate does not deteriorate. In all cases, the environmental impacts require thorough assessment. Climate change requires reduction as indicated in recent Conference of the Parties meetings.

Rainforest conversion to rubber and oil palm reduces abundance, biomass and diversity of canopy spiders

Rainforest canopies, home to one of the most complex and diverse terrestrial arthropod communities, are threatened by conversion of rainforest into agricultural production systems. However, little is known about how predatory arthropod communities respond to such conversion. To address this, we compared canopy spider (Araneae) communities from lowland rainforest with those from three agricultural systems in Jambi Province, Sumatra, Indonesia, i.e., jungle rubber (rubber agroforest) and monoculture plantations of rubber and oil palm. Using canopy fogging, we collected 10,676 spider specimens belonging to 36 families and 445 morphospecies. The four most abundant families (Salticidae N = 2,043, Oonopidae N = 1,878, Theridiidae N = 1,533 and Clubionidae N = 1,188) together comprised 62.2% of total individuals, while the four most speciose families, Salticidae (S = 87), Theridiidae (S = 83), Araneidae (S = 48) and Thomisidae (S = 39), contained 57.8% of all morphospecies identified. In lowland rainforest, average abundance, biomass and species richness of canopy spiders was at least twice as high as in rubber or oil palm plantations, with jungle rubber showing similar abundances as rainforest, and intermediate biomass and richness. Community composition of spiders was similar in rainforest and jungle rubber, but differed from rubber and oil palm, which also differed from each other. Canonical Correspondence Analysis showed that canopy openness, aboveground tree biomass and tree density together explained 18.2% of the variation in spider communities at family level. On a morphospecies level, vascular plant species richness and tree density significantly affected the community composition but explained only 6.8% of the variance. While abundance, biomass and diversity of spiders declined strongly with the conversion of rainforest into monoculture plantations of rubber and oil palm, we also found that a large proportion of the rainforest spider community can thrive in extensive agroforestry systems such as jungle rubber. Despite being very different from rainforest, the canopy spider communities in rubber and oil palm plantations may still play a vital role in the biological control of canopy herbivore species, thus contributing important ecosystem services. The components of tree and palm canopy structure identified as major determinants of canopy spider communities may aid in decision-making processes toward establishing cash-crop plantation management systems which foster herbivore control by spiders.

The role of information in consumer preferences for sustainable certified palm oil products in Germany

Food products are often subject to information asymmetries, which are commonly supposed to be reduced by labels and certifications. However, as the number of labels increases, consumers tend to get confused, bored or impatient and stop using them to make product choices. This study uses data from a discrete choice experiment, conducted in Germany, to analyze consumers’ preferences and willingness-to-pay (WTP) for sustainability indicators on products that contain palm oil as an ingredient. Since information is crucial to the assessment and awareness of, or attendance to, labels on consumer products, this study assesses the effect of factual information on preferences as well as attribute-processing strategies. We use a hybrid latent variable model that allows us to jointly examine the response to the stated choice component and the responses to attribute processing questions, thus capturing attribute non-attendance (ANA) to specific labels while controlling for heterogenous preferences. Our results reveal that the attribute ‘organic’ receives the highest monetary valuation in the overall sample as well as in the information intervention, and the no-information intervention groups. The results also show that providing additional information tends to change consumers’ non-attendance patterns as well as WTP values. In particular, the information intervention tends to increase consumers’ WTP and decreases their ANA for sustainability-indicating attributes. The findings suggest that the attribute ‘organic’ has the potential to be ranked highest across the entire latent variable structure, making it the most promising attribute for promoting sustainable palm oil use across consumer groups.

More sustainable vegetable oil: Balancing productivity with carbon storage opportunities

Intensive cultivation and post-harvest vegetable oil production stages are major sources of greenhouse gas (GHG) emissions. Variation between production systems and reporting disparity have resulted in discordance in previous emissions estimates. The aim of this study was to assess global systems-wide variation in GHG emissions resulting from palm, soybean, rapeseed and sunflower oil production. Such an analysis is critical to understand the implications of meeting increasing edible oil demand. To achieve this, we performed a unified re-analysis of life cycle input data from diverse palm, soybean, rapeseed, and sunflower oil production systems, from a saturating search of published literature. The resulting dataset reflects almost 6000 producers in 38 countries, and is representative of over 71% of global vegetable oil production. Across all oil crop systems, median GHG emissions were 3.81 kg CO2e per kg refined oil. Crop specific median emissions ranged from 2.49 kg CO2e for rapeseed oil to 4.25 kg CO2e for soybean oil per kg refined oil. Determination of the carbon cost of agricultural land occupation revealed that carbon storage potential in native compared to agricultural land cover drives variation in production GHG emissions, and indicates that expansion of production in low carbon storage potential land, whilst reforesting areas of high carbon storage potential, could reduce net GHG emissions whilst boosting productivity. Nevertheless, there remains considerable scope to improve sustainability within current production systems, including through increasing yields whilst limiting application of inputs with high carbon footprints, and in the case of palm oil through more widespread adoption of methane capture technologies in processing stages.

Riparian buffers made of mature oil palms have inconsistent impacts on oil palm ecosystems

Expansion of oil palm has caused widespread declines in biodiversity and changes in ecosystem functioning across the tropics. A major driver of these changes is loss of habitat heterogeneity as forests are converted into oil palm plantations. Therefore, one strategy to help support biodiversity and functioning in oil palm is to increase habitat heterogeneity, for instance, by retaining forested buffers around rivers when new plantations are established, or maintaining buffers made of mature oil palms ("mature palm buffers") when old plantations are replanted. While forested buffers are known to benefit oil palm systems, the impacts of mature palm buffers are less certain. In this study, we assessed the benefits of mature palm buffers, which were being passively restored (in this case, meaning that buffers were treated with no herbicides, pesticides, or fertilizers) by sampling environmental conditions and arthropods within buffers and in surrounding non-buffer areas (i.e., areas that were 25 and 125 m from buffers, and receiving normal business-as-usual management) across an 8-year chronosequence in industrial oil palm plantations (Sumatra, Indonesia). We ask (1) Do environmental conditions and biodiversity differ between buffer and non-buffer areas? (2) Do buffers affect environmental conditions and biodiversity in adjacent non-buffer areas (i.e., areas that were 25 m from buffers)? (3) Do buffers become more environmentally complex and biodiverse over time? We found that buffers can have environmental conditions (canopy openness, variation in openness, vegetation height, ground cover, and soil temperature) and levels of arthropod biodiversity (total arthropod abundance and spider abundance in the understory and spider species-level community composition in all microhabitats) that are different from those in non-buffer areas, but that these differences are inconsistent across the oil palm commercial life cycle. We also found that buffers might contribute to small increases in vegetation height and changes in ground cover in adjacent non-buffer areas, but do not increase levels of arthropod biodiversity in these areas. Finally, we found that canopy openness, variation in openness, and ground cover, but no aspects of arthropod biodiversity, change within buffers over time. Collectively, our findings indicate that mature palm buffers that are being passively restored can have greater environmental complexity and higher levels of arthropod biodiversity than non-buffer areas, particularly in comparison to recently replanted oil palm, but these benefits are not consistent across the crop commercial life cycle. If the goal of maintaining riparian buffers is to consistently increase habitat heterogeneity and improve biodiversity, an alternative to mature palm buffers or a move toward more active restoration of these areas is, therefore, probably required.

Water Regulation Ecosystem Services of Multifunctional Landscape Dominated by Monoculture Plantations

Meeting the growing demand for agricultural production while preserving water regulation ecosystem services (WRES) is a challenge. One way to preserve WRES is by adopting multifunctional landscape approach. Hence, the main objective was to evaluate the role of forest patches (FP) in preserving WRES in tropical landscapes dominated by oil palm plantations. The SWAT model was used to evaluate the essential WRES, such as water yield (WYLD), soil water (SW), surface runoff (SURQ), groundwater recharge (GWR), and evapotranspiration (AET). Due to a compaction, soils in monoculture plantation have higher bulk density and lower porosity and water retention, which decrease WRES. Conserving FP among oil palms evidently improves WRES, such as decreasing SURQ and rain season WYLD and increasing GWR, SW, AET, and dry season WLYD. FP has sponge-like properties by storing water to increase water availability, and pump-like properties by evaporating water to stabilize the microclimate. Mature oil palm also has pump-like properties to maintain productivity. However, it does not have sponge-like properties that make water use more significant than the stored water. Consequently, a multifunctional landscape could enhance WRES of forest patches and synergize it with provisioning ecosystem services of oil palm plantations.

Conservation and cultural intersections within Hong Kong's snake soup industry

Snake soup continues to be an iconic tradition in Cantonese culture. Yet little is known about the relationship between snake soup consumption in Hong Kong, wild snake populations, and the communities depending on this tradition for their livelihoods. We applied an interdisciplinary approach including interviews with shopkeepers and genetic analyses of snake meat samples to determine the species consumed in Hong Kong, their source locations, and shopkeepers’ views on the future of the industry. We genetically identified the common rat snake Ptyas mucosa, widely distributed throughout East and Southeast Asia, and the Javan spitting cobra Naja sputatrix, endemic to Indonesia, as the species most commonly consumed, which was consistent with interview responses. According to interviews, snakes had mostly been imported from mainland China in the past, but now tend to be sourced from Southeast Asia, particularly Indonesia. Interviews also revealed a pessimistic outlook on the continuation of this tradition because of various factors, including a lasting yet misinformed association of snakes with the 2002–2003 outbreak of severe acute respiratory syndrome. Given the COVID-19 pandemic and China's ensuing ban on the consumption of terrestrial wildlife, Hong Kong's snake soup industry will probably continue to rely on Southeast Asian sources to persist. Given the cultural and conservation issues surrounding this tradition, further research on the economic, ecological and social consequences of snake consumption is needed to examine the broader implications of snake soup and similar industries in the region.

Integrating remote sensing with ecology and evolution to advance biodiversity conservation

Remote sensing has transformed the monitoring of life on Earth by revealing spatial and temporal dimensions of biological diversity through structural, compositional and functional measurements of ecosystems. Yet, many aspects of Earth's biodiversity are not directly quantified by reflected or emitted photons. Inclusive integration of remote sensing with field-based ecology and evolution is needed to fully understand and preserve Earth's biodiversity. In this Perspective, we argue that multiple data types are necessary for almost all draft targets set by the Convention on Biological Diversity. We examine five key topics in biodiversity science that can be advanced by integrating remote sensing with in situ data collection from field sampling, experiments and laboratory studies to benefit conservation. Lowering the barriers for bringing these approaches together will require global-scale collaboration.

On the prediction of methane fluxes from pristine tropical peatland in Sarawak: application of a denitrification-decomposition (DNDC) model

Tropical peatlands have high potential function as a major source of atmospheric methane (CH₄) and can contribute to global warming due to their large soil carbon stock, high groundwater level (GWL), high humidity and high temperature. In this study, a process-based denitrification-decomposition (DNDC) model was used to simulate CH₄ fluxes in a pristine tropical peatland in Sarawak. To test the accuracy of the model, eddy covariance tower datasets were compared. The model was validated for the year 2014, which showed the good performance of the model for simulating CH₄ emissions. The monthly predictive ability of the model was better than the daily predictive ability, with a determination coefficient (R²) of 0.67, model error (ME) of 2.47, root mean square error (RMSE) of 3.33, mean absolute error (MAE) of 2.92 and mean square error (MSE) of 11.08. The simulated years of 2015 and 2016 showed the good performance of the DNDC model, although under- and overestimations were found during the drier and rainy months. Similarly, the monthly simulations for the year were better than the daily simulations for the year, showing good correlations at R² at 0.84 (2015) and 0.87 (2016). Better statistical performance in terms of monthly ME, RMSE, MAE and MSE at - 0.11, 3.38, 3.05 and 11.45 for 2015 and - 1.14, 5.28, 4.93 and 27.83 for 2016, respectively, was also observed. Although the statistical performance of the model simulation for daily average CH₄ fluxes was lower than that of the monthly average, we found that the results for total fluxes agreed well between the observed and the simulated values (E = 6.79% and difference = 3.3%). Principal component analysis (PCA) showed that CH₄, GWL and rainfall were correlated with each other and explained 41.7% of the total variation. GWL was found to be relatively important in determining the CH₄ fluxes in the naturally inundated pristine tropical peatland. These results suggest that GWL is an essential input variable for the DNDC model for predicting CH₄ fluxes from the pristine tropical peatland in Sarawak on a monthly basis.

Nexus between climate change and oil palm production in Malaysia: a review

Climate change is believed to be caused by natural processes such as volcanic eruptions, which release ash into the atmosphere, and anthropogenic activities that increase the concentration of greenhouse gases (GHGs) in the atmosphere, such as carbon dioxide (CO₂), which trap energy and cause intense warming. This article conducts a comprehensive review of existing literature relating to climate change and its impact on oil palm production in Malaysia. To enable analysis, articles were arranged, sorted, and categorized into various themes and associations based on the title of the article, abstract, and later the content. The findings reveal that climate change causes variability in the intensity and duration of rainfall, which ultimately affects the production of oil palm fresh fruit bunches (FFB) and the quality of crude palm oil (CPO). The decline in FFB increased the price of crude palm oil. The impacts of climate change on oil palm vary and are felt differently in different regions. Climate change increases the vulnerability and exposure of oil palms to various diseases, exposes them to water stress, and disrupts metabolic activities. The surface temperature in Malaysia is anticipated to rise by 1.5 to 2 °C, worsening the adaptation plans. Oil palm growers explore possible ways to adapt to and withstand the impacts of climate change by adopting the use of an improved variety of oil palm seedlings, soil management and fertility preservation, silt pit, mulching, intercropping, livelihood diversification, buying insurance, and best water conservation practices.

An integrated biorefinery strategy for the utilization of palm-oil wastes

Each year, the palm oil industry generates a significant amount of biomass residue and effluent waste; both have been identified as significant sources of greenhouse gas (GHG) emissions. This issue poses a severe environmental challenge for the industry due to the possibility of long-term negative effects on human well-being. The palm-oil industry must invest significantly in the technology that is required to resolve these issues and to increase the industry's sustainability. However, current technologies for converting wastes such as lignocellulosic components and effluents into biochemical products are insufficient for optimal utilization. This review discusses the geographical availability of palm-oil biomass, its current utilization routes, and then recommends the development of technology for converting palm-oil biomass into value-added products through an integrated biorefinery strategy. Additionally, this review summarizes the palm oil industry's contribution to achieving sustainable development goals (SDGs) through a circular bioeconomy concept.

Optimised and systematic suitable climate modelling confirms future longitudinal-trends for growing oil palm in Africa

Palms are iconic plants. Oil palms are very important economically and originate in Africa where they can act as a model for palms in general. The effect of future climate on the growth of oil palm will be very detrimental. Latitudinal migration of tropical crops to climate refuges may be impossible, and longitudinal migration has only been confirmed for oil palm, of all the tropical crops. The previous method to determine the longitudinal trend for oil palm used the longitudes of various countries in Africa and plotted these against the percentage suitable climate for growing oil palms in each country. An increasing longitudinal trend was observed from west to east. However, the longitudes of the countries were randomly distributed which may have introduced bias and the procedure was time consuming. The present report presents an optimised and systematic procedure that divided the regions, as presented on a map derived from a CLIMEX model, into ten equal sectors and the percentage suitable climates for growing oil palm were determined for each sector. This approach was quicker, systematic and straight forward and will be useful for management of oil palm plantations under climate change. The method confirmed and validated the trends reported in the original method although the suitability values were often lower and there was less spread of values around the trend. The values for the CSIRO MK3.0 and MIROC H models demonstrated considerable similarities to each other, contributing to validation of the method. The procedure of dividing maps equally into sectors derived from models, could be used for other crops, regions, or systems more generally, where the alternative may be a more superficial visual examination of the maps. Methods are required to mitigate the effects of climate change and stakeholders need to contribute more actively to the current climate debate with tangible actions.

Understanding the impacts on land use through GHG-water-land-biodiversity nexus: The case of oil palm plantations in Thailand

The promotion of biodiesel from palm oil for on-road transportation during the past decade has led to the expansion of oil palm plantations, including in Thailand. Hence, it is necessary to study the effects of land use for oil palm and the linkage between each impact for a holistic understanding. Besides, the consideration of various impact aspects in terms of a nexus is necessary for suggesting appropriate practices or zoning, because a single impact evaluation may not be comprehensive. Therefore, this study assessed the land use impacts from oil palm plantations in the five regions of Thailand. The land use impacts studied were greenhouse gas emissions, water scarcity, soil quality, and biodiversity. The assessment indicated the southern region to be the most suitable for further expansion of oil palm plantations, which is consistent with the government recommendation. However, if the expansion of oil palm in other regions is necessary, the central region is recommended because of available irrigation supply and better soil fertility compared to other regions. This study found that the land use impacts resulted from unsuitable management of oil palm plantations in the past. The increase of greenhouse gas emissions was mainly due to the excessive use of chemical fertilizers for soil quality improvement and water pumping from irrigation water consumption. Meanwhile, the deficiency of water availability led to the degradation of biodiversity and ecosystems. To decrease the land use impacts in the long run, suitable practice is important for sustainable oil palm plantations.

A global review of rubber plantations: Impacts on ecosystem functions, mitigations, future directions, and policies for sustainable cultivation

The growing global need for latex is driving rubber plantation (RP) expansion since the last century, with >2 Mha of cultivation area being established in the last decade. Southeast Asia is the hotspot for rubber cultivation at other land-use costs. Although rubber cultivation has improved the economic status of farmers, it has altered the habitat's ecology and ecosystem functions (EF). However, studies on the impacts of RP on EF are limited, and a clear overview is not available. To bridge this gap, we conducted an inclusive review of the EF of RP, including soil carbon storage, aboveground biomass (AGB) and belowground biomass (BGB), litter production and decomposition, respiration, and biodiversity (plants, animals, soil fauna, and microbes). We compared the EF in RP (monoculture) with those in forests because the conversion of forests to RP is prevalent in the tropics and because most RP studies used forests as reference ecosystems. We found RP generally have lower EF than forests. The impacts of RP on some EF are more severe (e.g., AGB, BGB, and plant diversity), causing decreases of >55%, and the effects are consistently negative irrespective of plantation age. However, including agroforestry or polyculture, integrated pest management, cover cropping, mulching, and composting can improve the EF in RP to some extent. We highlighted research gaps, particularly substantial research gaps concerning the influence of plant diversity treatments (i.e., agroforestry) performed in RP on EF. Additionally, more empirical data on the significance of spatial and temporal levels are required, such as how the impact on EF could vary with climate and RP age, as we showed some examples where EF differs spatially and temporally. More importantly, further research on plantation management to offset EF losses is needed. Finally, we emphasized knowledge gaps and suggested future directions and policies for improving EF in RP.

Predicting Heritability of Oil Palm Breeding Using Phenotypic Traits and Machine Learning

Oil palm is one of the main crops grown to help achieve sustainability in Malaysia. The selection of the best breeds will produce quality crops and increase crop yields. This study aimed to examine machine learning (ML) in oil palm breeding (OPB) using factors other than genetic data. A new conceptual framework to adopt the ML in OPB will be presented at the end of this paper. At first, data types, phenotype traits, current ML models, and evaluation technique will be identified through a literature survey. This study found that the phenotype and genotype data are widely used in oil palm breeding programs. The average bunch weight, bunch number, and fresh fruit bunch are the most important characteristics that can influence the genetic improvement of progenies. Although machine learning approaches have been applied to increase the productivity of the crop, most studies focus on molecular markers or genotypes for plant breeding, rather than on phenotype. Theoretically, the use of phenotypic data related to offspring should predict high breeding values by using ML. Therefore, a new ML conceptual framework to study the phenotype and progeny data of oil palm breeds will be discussed in relation to achieving the Sustainable Development Goals (SDGs).

Land-use change and biodiversity: Challenges for assembling evidence on the greatest threat to nature

Land-use change is considered the greatest threat to nature, having caused worldwide declines in the abundance, diversity, and health of species and ecosystems. Despite increasing research on this global change driver, there are still challenges to forming an effective synthesis. The estimated impact of land-use change on biodiversity can depend on location, research methods, and taxonomic focus, with recent global meta-analyses reaching disparate conclusions. Here, we critically appraise this research body and our ability to reach a reliable consensus. We employ named entity recognition to analyze more than 4000 abstracts, alongside full reading of 100 randomly selected papers. We highlight the broad range of study designs and methodologies used; the most common being local space-for-time comparisons that classify land use in situ. Species metrics including abundance, distribution, and diversity were measured more frequently than complex responses such as demography, vital rates, and behavior. We identified taxonomic biases, with vertebrates well represented while detritivores were largely missing. Omitting this group may hinder our understanding of how land-use change affects ecosystem feedback. Research was heavily biased toward temperate forested biomes in North America and Europe, with warmer regions being acutely underrepresented despite offering potential insights into the future effects of land-use change under novel climates. Various land-use histories were covered, although more research in understudied regions including Africa and the Middle East is required to capture regional differences in the form of current and historical land-use practices. Failure to address these challenges will impede our global understanding of land-use change impacts on biodiversity, limit the reliability of future projections and have repercussions for the conservation of threatened species. Beyond identifying literature biases, we highlight the research priorities and data gaps that need urgent attention and offer perspectives on how to move forward.

Oil palm in the 2020s and beyond: challenges and solutions

BACKGROUND

Oil palm, Elaeis guineensis, is by far the most important global oil crop, supplying about 40% of all traded vegetable oil. Palm oils are key dietary components consumed daily by over three billion people, mostly in Asia, and also have a wide range of important non-food uses including in cleansing and sanitizing products.

MAIN BODY

Oil palm is a perennial crop with a > 25-year life cycle and an exceptionally low land footprint compared to annual oilseed crops. Oil palm crops globally produce an annual 81 million tonnes (Mt) of oil from about 19 million hectares (Mha). In contrast, the second and third largest vegetable oil crops, soybean and rapeseed, yield a combined 84 Mt oil but occupy over 163 Mha of increasingly scarce arable land. The oil palm crop system faces many challenges in the 2020s. These include increasing incidence of new and existing pests/diseases and a general lack of climatic resilience, especially relating to elevated temperatures and increasingly erratic rainfall patterns, plus downstream issues relating to supply chains and consumer sentiment. This review surveys the oil palm sector in the 2020s and beyond, its major challenges and options for future progress.

CONCLUSIONS

Oil palm crop production faces many future challenges, including emerging threats from climate change and pests and diseases. The inevitability of climate change requires more effective international collaboration for its reduction. New breeding and management approaches are providing the promise of improvements, such as much higher yielding varieties, improved oil profiles, enhanced disease resistance, and greater climatic resilience.

Impacts of and adaptation to climate change on the oil palm in Malaysia: a systematic review

The interaction and the interplay of climate change with oil palm production in the Southeast Asia region are of serious concern. This particularly applies in Malaysia due to its rank as the second largest palm oil producer in the world. The anthropogenic activities and the agroecological practices in oil palm plantation, including excessive use of fertilisers, bush fire due to land clearing, and cultivation on peatland, have exacerbated the effects of climate change featuring extreme events, drought, flooding, heatwave, as well as infestation of pest and diseases. These adverse impacts on oil palm production highlight the significance of deploying effective adaptation strategies. The study aims to examine the impact of climate change on oil palm production and identify the farmers' adaptation strategies to the impacts of climate change in Malaysia. This study was conducted a comprehensive review of the articles published from 2000 to 2021 in the contexts of climate change and oil palm production in Malaysia. The review shows that climate change has a range of impacts on the oil palm production in Malaysia. As a result, several adaptation options were identified, such as breeding of hybrid varieties that are tolerant and resistant to heat; sustainable management of soil; pit and tranches to enhance water management in plantation areas; minimal use of fertilisers, herbicides, and pesticides; zero burning; and minimum tillage. The reviewed studies recommended the following to mitigate the adverse impacts of climate change: sustainable national policy on climate change, conservation of the existing carbon stock, effective management of tropical rainforest biodiversity, afforestation for carbon sequestration, and reduction in greenhouse gas (GHG) emission.

Alterations in Mycelial Morphology and Flow Cytometry Assessment of Membrane Integrity of Ganoderma boninense Stressed by Phenolic Compounds

Global increase in demand for palm oil has caused an intensification in oil palm plantation; however, production is greatly hindered by Basal Stem Rot (BSR) disease caused by Ganoderma boninense. There are many approaches to controlling BSR, although, there is no accurate, sustainable and effective method to suppress G. boninense completely. Hence, four phenolic compounds [Gallic acid (GA), Thymol (THY), Propolis (PRO) and Carvacrol (CARV)] were selected to evaluate their antifungal effect, ability to alter the mycelium morphology, and fungal cell integrity against G. boninense. Significant differences (p < 0.05) were observed and 94% of inhibition was exerted by GA on G. boninense growth. Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy observations revealed that GA and THY treatment caused severe damage to the mycelium and recorded the highest amount of sugar and electrolyte leakage. The study of cell integrity and morphological disruption has elucidated the reduction of G. boninense cell viability. Generally, our findings confirm the fungistatic effects of GA and THY. The evolution of phenolic compounds during the phytopathology studies indicated their coherence in eradicating the G. boninense. It is proposed that GA and THY had the potential to be developed further as a natural antifungal treatment to suppress G. boninense.

Evaluating the Inclusion of Cold-Pressed Rapeseed Cake in the Concentrate for Dairy Cows upon Ruminal Biohydrogenation Process, Ruminal Microbial Community and Milk Production and Acceptability

The aim of this trial was to assess the effect of feeding a concentrate including cold-pressed rapeseed cake (CPRC) on productive performance, milk quality and its sensory properties, ruminal biohydrogenation, and bacterial communities. Eighteen cows were paired, and two experimental diets (control vs. CPRC) were distributed within the pair. Concentrates were iso-energetic and iso-proteic and contained similar amounts of fat. The average days in milk, milk yield, and body weight of the animals were (mean ± SD) 172 ± 112 d, 585 ± 26 kg, and 25.4 ± 6.2 kg/d, respectively. The experiment lasted for 10 wk. Feeding CPRC resulted in lower ruminal saturated (p < 0.001) and higher monounsaturated (p = 0.002) fatty acids. Feeding CPRC increased Ruminococcus, Prevotella, and Entodinium but decreased Blautia; p-75-a5; undefined genera within orders Clostridiaceae and RF39 and within families Christensenellaceae, Lachnospiracease, and Ruminococcaceae; and fungi from the phylum neocallimastigomycota. The milk fatty acid profile was characterized by a lower n6:n3 ratio (p = 0.028). Feeding CPRC did not affect the milk yield, milk quality, or fat corrected milk (p > 0.05). Feeding CPRC improved the overall milk acceptability (p = 0.047). In conclusion, CPRC affected some microbial taxa, modified the biohydrogenation process, and improved the milk fatty acid profile and consumer acceptance without detrimental effects on milk production and composition.

Longitudinal trends of future climate change and oil palm growth: empirical evidence for tropical Africa

Palms are highly significant tropical plants. Oil palms produce palm oil, the basic commodity of a highly important industry. Climate change from greenhouse gasses is likely to decrease the ability of palms to survive, irrespective of them providing ecosystem services to communities. Little information about species survival in tropical regions under climate change is available and data on species migration under climate change is important. Palms are particularly significant in Africa: a palm oil industry already exists with Nigeria being the largest producer. Previous work using CLIMEX modelling indicated that Africa will have reduced suitable climate for oil palm in Africa. The current paper employs this modelling to assess how suitable climate for growing oil palm changed in Africa from current time to 2100. An increasing trend in suitable climate from west to east was observed indicating that refuges could be obtained along the African tropical belt. Most countries had reduced suitable climates but others had increased, with Uganda being particularly high. There may be a case for developing future oil palm plantations towards the east of Africa. The information may be usefully applied to other palms. However, it is crucial that any developments will fully adhere to environmental regulations. Future climate change will have severe consequences to oil palm cultivation but there may be scope for eastwards mitigation in Africa.

Shifts in mosquito diversity and abundance along a gradient from oil palm plantations to conterminous forests in Borneo

Deforestation precipitates spillover of enzootic, vector-borne viruses into humans, but specific mechanisms for this effect have rarely been investigated. Expansion of oil palm cultivation is a major driver of deforestation. Here, we demonstrate that mosquito abundance decreased over ten stepwise distances from interior forest into conterminous palm plantations in Borneo. Diversity in interior plantation narrowed to one species, Aedes albopictus, a potential bridge vector for spillover of multiple viruses. A. albopictus was equally abundant across all distances in forests, forest-plantation edge, and plantations, while A. niveus, a known vector of sylvatic dengue virus, was found only in forests. A. albopictus collections were significantly female-biased in plantation but not in edge or forest. Our data reveal that the likelihood of encountering any mosquito is greater in interior forest and edge than plantation, while the likelihood of encountering A. albopictus is equivalent across the gradient sampled from interior plantation to interior forest.

Changes in diversity and community assembly of jumping spiders (Araneae: Salticidae) after rainforest conversion to rubber and oil palm plantations

Rainforest conversion into monoculture plantations results in species loss and community shifts across animal taxa. The effect of such conversion on the role of ecophysiological properties influencing communities, and conversion effects on phylogenetic diversity and community assembly mechanisms, however, are rarely studied in the same context. Here, we compare salticid spider (Araneae: Salticidae) communities between canopies of lowland rainforest, rubber agroforest (“jungle rubber”) and monoculture plantations of rubber or oil palm, sampled in a replicated plot design in Jambi Province, Sumatra, Indonesia. Overall, we collected 912 salticid spider individuals and sorted them to 70 morphospecies from 21 genera. Salticid richness was highest in jungle rubber, followed by rainforest, oil palm and rubber, but abundance of salticids did not differ between land-use systems. Community composition was similar in jungle rubber and rainforest but different from oil palm and rubber, which in turn were different from each other. The four investigated land-use systems differed in aboveground plant biomass, canopy openness and land use intensity, which explained 12% of the observed variation in canopy salticid communities. Phylogenetic diversity based on ~850 bp 28S rDNA fragments showed similar patterns as richness, that is, highest in jungle rubber, intermediate in rainforest, and lowest in the two monoculture plantations. Additionally, we found evidence for phylogenetic clustering of salticids in oil palm, suggesting that habitat filtering is an important factor shaping salticid spider communities in monoculture plantations. Overall, our study offers a comprehensive insight into the mechanisms shaping communities of arthropod top predators in canopies of tropical forest ecosystems and plantations, combining community ecology, environmental variables and phylogenetics across a land-use gradient in tropical Asia.

Current strategies and perspectives in detection and control of basal stem rot of oil palm

The rapid expansion of oil palm (OP) has led to its emergence as a commodity of strategic global importance. Palm oil is used extensively in food and as a precursor for biodiesel. The oil generates export earnings and bolsters the economy of many countries, particularly Indonesia and Malaysia. However, oil palms are prone to basal stem rot (BSR) caused by Ganoderma boninense which is the most threatening disease of OP. The current control measures for BSR management including cultural practices, mechanical and chemical treatment have not proved satisfactory. Alternative control measures to overcome the G. boninense problem are focused on the use of biological control agents and many potential bioagents were identified with little proven practical application. Planting OP varieties resistant to G. boninense could provide the ideal long-term solution to basal stem rot. The total resistance of palms to G. boninense has not yet been reported, and few examples of partial resistances have been observed. Importantly, basidiospores are now recognized as the method by which the disease is spread, and control methods require to be revaluated because of this phenomenon. Many methods developed to prevent the spread of the disease effectively are only tested at nursery levels and are only reported in national journals inhibiting the development of useful techniques globally. The initial procedures employed by the fungus to infect the OP require consideration in terms of the physiology of the growth of the fungus and its possible control. This review assesses critically the progress that has been made in BSR development and management in OP.

Species Richness and Carbon Footprints of Vegetable Oils: Can High Yields Outweigh Palm Oil’s Environmental Impact?

Palm oil has been widely criticised for its high environmental impacts, leading to calls to replace it with alternative vegetable oils in food and cosmetic products. However, substituting palm oil would be environmentally beneficial only if the environmental footprint per litre oil were lower than those of alternative vegetable oils. Whether this is the case is not obvious, given the high oil yields of oil palm of up to 10 times those of alternative crops. Here, we combine global agricultural and environmental datasets to show that, among the world’s seven major vegetable oil crops (oil palm, soybean, rapeseed, sunflower, groundnut, coconut, olive), oil palm has the lowest average species richness and carbon footprint associated with an annual production of one litre of vegetable oil. For each crop, these yield-adjusted footprints differ substantially between major producer countries, which we find to be largely the result of differences in crop management. Closing agricultural yield gaps of oil crops through improved management practices would significantly reduce the environmental footprints per oil yield. This would minimise the need for further land conversion to oil cropland and indeed could increase production to such an extent that a significant area of oil croplands could be ecologically restored.

Agroforestry as Policy Option for Forest-Zone Oil Palm Production in Indonesia

With 15–20% of Indonesian oil palms located, without a legal basis and permits, within the forest zone (‘Kawasan hutan’), international concerns regarding deforestation affect the totality of Indonesian palm oil export. ‘Forest zone oil palm’ (FZ-OP) is a substantive issue that requires analysis and policy change. While spatial details of FZ-OP remain contested, we review literature on (1) the legal basis of the forest zone and its conversion, (2) social stratification in oil palm production (large-scale, plasma and independent growers), and (3) environmental consequences of forest conversion to FZ-OP, before discussing policy options in a range of social and ecological contexts. Policy options range from full regularization (as FZ-OP stands could meet international forest definitions), to conditional acceptance of diversified smallholder plantings in ‘agroforestry concessions’, to gradually phasing out FZ-OP and eviction/destruction. A nuanced and differentiated approach to FZ-OP is needed, as certification of legality along supply chains is vulnerable to illegal levies and corruption. Corporate actors trading internationally can avoid use of uncertified raw materials, effectively shifting blame and depressing farmgate prices for domestic-market palm oil, but this will not return forest conditions or stop further forest conversion. We discuss an agenda for follow-up policy research.

The environmental impacts of palm oil in context

Delivering the Sustainable Development Goals (SDGs) requires balancing demands on land between agriculture (SDG 2) and biodiversity (SDG 15). The production of vegetable oils and, in particular, palm oil, illustrates these competing demands and trade-offs. Palm oil accounts for ~40% of the current global annual demand for vegetable oil as food, animal feed and fuel (210 Mt), but planted oil palm covers less than 5-5.5% of the total global oil crop area (approximately 425 Mha) due to oil palm's relatively high yields. Recent oil palm expansion in forested regions of Borneo, Sumatra and the Malay Peninsula, where >90% of global palm oil is produced, has led to substantial concern around oil palm's role in deforestation. Oil palm expansion's direct contribution to regional tropical deforestation varies widely, ranging from an estimated 3% in West Africa to 50% in Malaysian Borneo. Oil palm is also implicated in peatland draining and burning in Southeast Asia. Documented negative environmental impacts from such expansion include biodiversity declines, greenhouse gas emissions and air pollution. However, oil palm generally produces more oil per area than other oil crops, is often economically viable in sites unsuitable for most other crops and generates considerable wealth for at least some actors. Global demand for vegetable oils is projected to increase by 46% by 2050. Meeting this demand through additional expansion of oil palm versus other vegetable oil crops will lead to substantial differential effects on biodiversity, food security, climate change, land degradation and livelihoods. Our Review highlights that although substantial gaps remain in our understanding of the relationship between the environmental, socio-cultural and economic impacts of oil palm, and the scope, stringency and effectiveness of initiatives to address these, there has been little research into the impacts and trade-offs of other vegetable oil crops. Greater research attention needs to be given to investigating the impacts of palm oil production compared to alternatives for the trade-offs to be assessed at a global scale.

The environmental impacts of palm oil in context

Delivering the Sustainable Development Goals (SDGs) requires balancing demands on land between agriculture (SDG 2) and biodiversity (SDG 15). The production of vegetable oils and, in particular, palm oil, illustrates these competing demands and trade-offs. Palm oil accounts for ~40% of the current global annual demand for vegetable oil as food, animal feed and fuel (210 Mt), but planted oil palm covers less than 5-5.5% of the total global oil crop area (approximately 425 Mha) due to oil palm's relatively high yields. Recent oil palm expansion in forested regions of Borneo, Sumatra and the Malay Peninsula, where >90% of global palm oil is produced, has led to substantial concern around oil palm's role in deforestation. Oil palm expansion's direct contribution to regional tropical deforestation varies widely, ranging from an estimated 3% in West Africa to 50% in Malaysian Borneo. Oil palm is also implicated in peatland draining and burning in Southeast Asia. Documented negative environmental impacts from such expansion include biodiversity declines, greenhouse gas emissions and air pollution. However, oil palm generally produces more oil per area than other oil crops, is often economically viable in sites unsuitable for most other crops and generates considerable wealth for at least some actors. Global demand for vegetable oils is projected to increase by 46% by 2050. Meeting this demand through additional expansion of oil palm versus other vegetable oil crops will lead to substantial differential effects on biodiversity, food security, climate change, land degradation and livelihoods. Our Review highlights that although substantial gaps remain in our understanding of the relationship between the environmental, socio-cultural and economic impacts of oil palm, and the scope, stringency and effectiveness of initiatives to address these, there has been little research into the impacts and trade-offs of other vegetable oil crops. Greater research attention needs to be given to investigating the impacts of palm oil production compared to alternatives for the trade-offs to be assessed at a global scale.

Legacy Effects Overshadow Tree Diversity Effects on Soil Fungal Communities in Oil Palm-Enrichment Plantations

Financially profitable large-scale cultivation of oil palm monocultures in previously diverse tropical rain forest areas constitutes a major ecological crisis today. Not only is a large proportion of the aboveground diversity lost, but the belowground soil microbiome, which is important for the sustainability of soil function, is massively altered. Intermixing oil palms with native tree species promotes vegetation biodiversity and stand structural complexity in plantations, but the impact on soil fungi remains unknown. Here, we analyzed the diversity and community composition of soil fungi three years after tree diversity enrichment in an oil palm plantation in Sumatra (Indonesia). We tested the effects of tree diversity, stand structural complexity indices, and soil abiotic conditions on the diversity and community composition of soil fungi. We hypothesized that the enrichment experiment alters the taxonomic and functional community composition, promoting soil fungal diversity. Fungal community composition was affected by soil abiotic conditions (pH, N, and P), but not by tree diversity and stand structural complexity indices. These results suggest that intensive land use and abiotic filters are a legacy to fungal communities, overshadowing the structuring effects of the vegetation, at least in the initial years after enrichment plantings.