Search

Interactions between the Sumatran tiger Panthera tigris sumatrae and people (e.g. injury or loss of lives of people and tigers, evacuation of injured tigers, loss of livestock and sightings of tigers) can negatively affect the conservation of the subspecies. Land-use change in Sumatra has reduced habitat for tigers, forcing them into human-dominated landscapes and increasing the probability of interactions with people. Although the number of such interactions is high in South-east Asia, few studies have been published since 2000 and for Sumatra there is a lack of information regarding where these events occur. We collated data on human–tiger interactions in the province of Riau using web scraping of news sources published during 2010–2020, and mapped these data to village boundaries. We recorded 101 interaction events, with a total of 107 interactions, which we categorized into seven types (people injured or killed, livestock killed, sightings of tigers, tigers killed, injured or evacuated), in 78 villages. Most interactions with reported locations occurred close to settlements (35%), followed by in plantations (26%) and smallholdings (25%), with forests and forest edges comprising 14% of such events. Interactions were dominated by sightings of tigers, but severe interaction types (human death or injury and attacks on livestock) were also reported. The mean annual number of human–tiger interactions was 4.6 during 2011–2017 and 21.3 during 2017–2020. We highlight the need for mitigation and prevention, such as establishing conflict mitigation teams, improving animal husbandry practices, and providing training and education on human–tiger interactions focused in plantations and settlements. Ministry of Education (MOE) National Research Foundation (NRF) Published version This research was supported by the Earth Observatory of Singapore via its funding from the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative. This work comprises Earth Observatory of Singapore contribution number 454.

India is the world’s largest consumer and importer of palm oil. In an aggressive push towards self-sufficiency in vegetable oils, the Indian government is prioritizing the rapid expansion of domestic oil palm plantations to meet an expected doubling in palm oil consumption in the next 15 years. Yet the current expansion of oil palm in India is occurring at the expense of biodiversity-rich landscapes. Using a spatially explicit model, we show that at the national scale India appears to have viable options to satisfy its projected national demand for palm oil without compromising either its biodiversity or its food security. At finer spatial scales, India’s oil palm expansion needs to incorporate region-specific contingencies and account for trade-offs between biodiversity conservation, climate change, agricultural inputs and economic and social security. The policy decisions that India takes with respect to oil palm can substantially reduce future pressures to convert forests to oil palm plantations in the tropics globally. The current expansion of oil palm in India is occurring at the expense of biodiversity-rich landscapes. This study shows that on the national scale India has the potential to become self-sufficient in palm oil production without compromising either its biodiversity or its food security, while economic, social, political and nutritional factors will require attention at finer spatial scales.

Vietnam is a major rice producer, and much of the rice grown is concentrated in the Red River Delta (RRD) and the Mekong River Delta (MRD). While the two deltas are highly productive regions, they are vulnerable to natural hazards and the effects of human-induced environmental change. To show that the processes and issues affecting food security are reinforcing, interdependent and operating at multiple scales, we used a systems-thinking approach to represent the major linkages between anthropogenic land-use and natural hazards and elaborate on how the drivers and environmental processes interact and influence rice growing area, rice yield and rice quality in the two deltas. On a local scale, demand for aquaculture and alternative crops, urban expansion, dike development, sand mining and groundwater extraction decrease rice production in the two deltas. Regionally, upstream dam construction impacts rice production in the two deltas despite being distally situated. Separately, the localized natural hazards that have adversely affected rice production include droughts, floods and typhoons. Outbreaks of pests and diseases are also common. Climate-change-induced sea level rise is a global phenomenon that will affect agricultural productivity. Notably, anthropogenic developments meant to improve agricultural productivity or increase economic growth can create many unwanted environmental consequences such as an increase in flooding, saltwater intrusion and land subsidence, which in turn decreases rice production and quality. In addition, natural hazards may amplify the problems created by human activities. Our meta-analysis highlights the ways in which a systems-thinking approach can yield more nuanced perspectives to tackle “wicked” and interrelated environmental challenges. Given that deltas worldwide are globally significant for food production and are highly stressed and degraded, a systems-thinking approach can be applied to provide a holistic and contextualized overview of the threats faced in each location.

Fire represents a mainstay for rural communities managing tropical landscapes. However, increasing uncontrolled fires in tropical landscapes because of land use and climate change pose a major threat to livelihoods, public health, and ecosystems. Peatlands in Southeast Asia are one such example of tropical landscapes that experience high flammability due to clearance of forests and excessive drainage for agriculture and forestry. The degradation of tropical peatland ecosystems increases their susceptibility to landscapes fires, which in turn increase the vulnerability of people and peatland conditions to future fires. To identify locations of tropical peatlands and surrounding communities that are vulnerable to fires, we conducted a socio-ecological vulnerability assessment and mapped the socio-ecological vulnerability of tropical peatlands to fires. We used an inductive approach to conceptualize and operationalize vulnerability and its associated dimensions of exposure, sensitivity, and adaptive capacity through empirical case studies in the literature, with a focus on tropical peatlands and fires in Indonesia. We present preliminary results of our mapped social and ecological vulnerability of Indonesia’s tropical peatlands to peat landscape fires. This would allow policymakers to identify places which display both high ecological and social vulnerability to fires and channel aid and mitigation efforts where they are most urgently needed.

Fire plays an important role in the earth system. While some aspects of fire including burnt area and fire frequencies have been extensively studied; fire carbon emissions, which could exert significant influence on the carbon cycle and a wide range of geophysical processes relating to ecosystem services and human well-being, are relatively understudied in terms of its global trends and drivers. We investigated fire emission trends from 2001 to 2019 at global and regional scales using total carbon emission data from the fourth generation Global Fire Emission Database (GFED4s). We identified geophysical and anthropogenic drivers for fire emission trends for regions defined by geographical regions and biomes with a causal model; and quantified driver importance with machine learning models by estimating their impact on fire emissions. We observed an insignificant global fire emission trend; mainly caused by conflicting fire emission trends in tropical savanna/grasslands and boreal forests. The two biomes were the largest sources for global fire emissions. Tropical savanna/grasslands contributed 60% to global fire emissions and showed a decreasing fire emission trend at a rate of -9.7±1.4 ×10 12 gC/year; boreal forests contributed around 8% and increased at a rate of 7.4±2.2 × 10 12 gC/year (rates estimated by Huber robust regression). At the regional scale, we found that fire emission trends were driven by geophysical factors for all regions. Anthropogenic interventions only caused changes in fire emissions in limited regions, including all biomes in Africa, and some biomes in Boreal Asia, Central Asia and North America. Decreasing fire emission trends in tropical savanna/grasslands mainly occurred in Africa; and the most dominant drivers were anthropogenic interventions, namely agriculture expansion and the subsequent declines in vegetation. Increasing fire emissions from boreal forests largely came from Boreal Asia, where anthropogenic interventions were also important drivers, and climatic drivers relating to moisture, drought, and temperature played a vital role as well, especially moisture. Vegetation indices were also identified as drivers for this region but were the least important ones. Our results suggested future fire emission trend for boreal forests in Boreal Asia could be highly vulnerable to climate change. It is possible that fire emissions in this region continue to increase if the climate becomes drier since drivers relating to moisture were highly important. On the other hand, further decrease for fire emissions in African savanna/grasslands is limited by the already shrunk vegetation. Therefore, at the global scale, risks of increasing fire carbon emissions are rather high. Increasing carbon emissions and the slow recovery of carbon sink capacity in burnt forests imply long-term net carbon source from boreal forests, which could be challenging for climate mitigation. Nanyang Technological University S.W., S.W.S. and J.S.H.L. 598 receive financial support from an Imperial-NTU Seed Grant (INCF-2021-006) for this study. S.W. is 599 supported by NTU Research Scholarship (PhD).

Information on agriculture-related damage and losses in Asia is under-reported in major multi-peril disaster databases. National disaster databases in some countries may have information on agricultural losses, but this information is not always available. We address this knowledge gap by creating a database of cyclone-induced rice damage from 1970–2018 for four major rice producing countries in Asia which experience frequent and intense tropical cyclones as a result of their geographical location (Philippines, Vietnam, Bangladesh, and Myanmar). We collated information using online news sources on rice damage locations, rice area damaged, loss in rice production, and loss in rice value from 1970–2018. Of the 1,046 cyclone events recorded, 138 events were associated with rice damage and loss, and majority of these events (93 %) happened in the Philippines and Vietnam. The average area of rice damaged per cyclone event ranged from 42,407 ha in Vietnam to 423,075 ha in Myanmar. The average rice production loss per cyclone event ranged from 460,667 metric tonnes in Bangladesh to 2,943,088 metric tonnes in the Philippines. Losses in rice production value from 1970–2018 were only reported in the Philippines and amounted to an average of US$42 million per cyclone event. Although Category 4 events tend to cause the most damage, tropical storms and Category 1 events were more frequent, especially in Vietnam. While our study is limited by the availability and quality of online news sources, we provide an assessment of rice agricultural damage from tropical cyclones in major rice producing countries in Asia.

Tropical deforestation is increasingly driven by the expansion of agricultural commodity production. Mapping commodity crops is an important step towards monitoring commodity-driven deforestation. Advances in remote sensing technology, such as the availability of high-resolution imagery and the combination of optical and radar imagery have enabled the detection of the tree-like crops which are difficult to distinguish from forest cover. Cashew is an example of a tree-like crop that grows in areas with high forest cover and biodiversity. Cashew is reported to occupy ∼7.1 million ha globally yet mapping it has been constrained by unclear boundaries due to spatial mixing with forests, an indistinct spectral signature, and structural composition that resembles forests. We employed optical, radar, and a combination of the two imagery types to detect and map cashew monocultures in south Maharashtra, India for 2020. We performed a land cover classification on Google Earth Engine using Random Forest, Classification And Regression Trees and Support Vector Machine algorithms. The combination of Sentinel-2 and Sentinel-1 SAR imagery using Random Forest algorithm yielded the highest unbiased overall accuracy (83%) and unbiased producer's and user's accuracies of 71% and 86% respectively for cashew land cover and was considered the best approach. According to our best approach, monoculture cashew plantations occupy 53,350.37 ha of total land area in the Sawantwadi- Dodamarg landscape in India. This study shows that a combination of optical and radar imagery can be used for cashew land cover classification in the Western Ghats, and future studies could modify these methods for cashew mapping in other landscapes. This study contributes to a growing body of literature supporting the use of both optical and radar imagery for detecting tree-like crop cover. Ministry of Education (MOE) National Research Foundation (NRF) Published version Funding for the study was provided by the Singaporean Ministry of Education Academic Tier 1 Research Funds (RG145/19 (NS)) and the Navjot Sodhi Conservation Research Award 2021. This research was supported by the Earth Observatory of Singapore via its funding from the National Research Foundation Singapore and the Singapore Ministry of Education under the Research Centres of Excellence initiative.

China’s decision to ban the trade and consumption of terrestrial wild animals, while controversial, is a viable response to the COVID-19 pandemic. The ban has implications that extend beyond safeguarding human health to also help combat illegal wildlife trade and protect threatened species.

As climate change continues to threaten human and natural systems, the search for cost-effective and practical mitigation solutions is gaining momentum. Reforestation has recently been identified as a promising nature-based climate solution. Yet there are context-dependent biophysical, financial, land-use and operational constraints to reforestation that demand careful consideration. Here, we show that 121 million ha of presently degraded land in Southeast Asia, a region noted for its significant reforestation potential, are biophysically suitable for reforestation. Reforestation of this land would contribute 3.43 ± 1.29 PgCO2e yr−1 to climate mitigation through 2030. However, by taking a combination of on-the-ground financial, land use and operational constraints into account, we find that only a fraction of that mitigation potential may be achievable (0.3–18%). Such constraints are not insurmountable, but they show that careful planning and consideration are needed for effective landscape-scale reforestation. Reforestation has been recently identified as a promising climate mitigation option. In Southeast Asia, 120 million ha of land are biophysically suitable for reforestation. However, financial, land-use and operational factors constrain mitigation potential to a fraction of its total possible value.

Efforts to shift unsustainable human behaviour are at the crux of many conservation interventions, particularly when addressing illegal or unsustainable wildlife trade. These efforts, often in the form of behaviour change interventions, have proven largely unable to counteract this pervasive issue, however, leading to calls for more robust intervention designs. In behavioural science fields like public health, design processes that integrate human behaviour theory and evidence from data collection are often developed to ground behaviour change interventions within a strong understanding of the context, thus supporting interventions that are efficient and have a higher likelihood of success. Here we detail the foundational process of designing an intervention around the use of a wildlife product by a particular group: Singaporean consumers of saiga horn (from the Critically Endangered Saiga tatarica). We employ both qualitative and quantitative data, along with human behaviour theories and past literature on the study system, to develop a comprehensive understanding of the many influences driving this target audience to purchase saiga horn products. We use this insight to identify the key influences to leverage in a behaviour change intervention: those that are both the most powerful and the most amenable to change. This work provides a reproducible process which can be used by other intervention implementers, highlights the often complex intricacies of socially influenced behaviour, and demonstrates why a methodical understanding of these intricacies is invaluable when attempting to shift human behaviour for conservation goals. A free Plain Language Summary can be found within the Supporting Information of this article.

Interventions to shift the behaviour of consumers using unsustainable wildlife products are key to threatened species conservation. Whether these interventions are effective is largely unknown due to a dearth of detailed evaluations. We previously conducted a country-level online behaviour change intervention targeting consumers of the Critically Endangered saiga antelope (Saiga tatarica) horn in Singapore. To evaluate intervention impact, we carried out in-person consumer surveys with >2,000 individuals pre- and post-intervention (2017 and 2019), and 93 in-person post-intervention surveys with traditional Chinese medicine (TCM) shopkeepers (2019). The proportion of self-reported high-usage saiga horn consumers in the target audience (Chinese Singaporean women aged 35–59) did not change significantly from pre- to post-intervention (24.4% versus 22.6%). However, post-intervention the target audience was significantly more likely than the non-target audience to accurately recall the intervention message and to report a decrease in saiga horn usage (4% versus 1% reported a behaviour change). Within the target audience, high-usage consumers were significantly more likely than lower-usage consumers to recall the message and report a behaviour change. Across respondents who reported a decrease in saiga horn usage, they cited the intervention message as a specific reason for their behaviour change significantly more than other reasons. Additionally, across all respondents, the belief that saiga is a common species in the wild decreased significantly from pre- to post-intervention. TCM shopkeepers, however, cited factors such as price and availability as the strongest influences on saiga horn sales. In sum, the intervention did significantly influence some consumers but the reduction of high-usage consumer frequency was not significant at the population level. We explore reasons for these findings, including competing consumer influences, characteristics of the intervention, and evaluation timing. This work suggests our intervention approach has potential, and exemplifies a multi-pronged in-person evaluation of an online wildlife trade consumer intervention. Published version This research was funded by Oxford University through the Oxford Martin Programme on the Illegal Wildlife Trade (grant held by author EJMG). The funder provided support in the form of salaries for authors (EJMG, DV) and fieldwork costs but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section of the manuscript.

About half of the world's tropical peatlands occur in Southeast (SE) Asia, where they serve as a major carbon (C) sink. Nearly 80% of natural peatlands in this region have been deforested and drained, with the majority under plantations and agriculture. This conversion increases peat oxidation which contributes to rapid C loss to the atmosphere as greenhouse gas emissions and increases their vulnerability to fires which generate regional smoke haze that has severe impacts on human health. Attempts at restoring these systems to mitigate environmental problems have had limited success. We review the current understanding of intact and degraded peatlands in SE Asia to help develop a way forward in restoring these ecosystems. As such, we critically examine them in terms of their biodiversity, C storage, hydrology and nutrients, paying attention to both above-ground and below-ground subsystems. We then propose an approach for better management and restoration of degraded peatlands that involves explicit consideration of multiple interacting ecological factors and the involvement of local communities who rely on converted peatlands for their livelihood. We make the case that as processes leading to peatland development involve modification of both above-ground and below-ground subsystems, an integrated approach that explicitly recognizes both subsystems and their interactions is key to successful tropical peatland management and restoration. Synthesis and applications. Gaining a better understanding of not just carbon stores and their changes during peat degradation, but also an in-depth understanding of the biota, nutrient dynamics, hydrology and biotic and abiotic feedbacks, is key to developing better solutions for the management and restoration of peatlands in Southeast Asia. Through the application of science- and nature-based solutions that recognize the interactions among the above-ground and below-ground subsystems, and taking into account the livelihood needs of local people, we propose a way to mitigate the ongoing environmental damage that is occurring in these iconic and unique ecosystems. Ministry of Education (MOE) National Research Foundation (NRF) Singapore Ministry of Education, Grant/Award Number: MOE2018-T2-2-156; National Research Foundation, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) Programme, Grant/Award Number: NRF2016-ITCOO1-021.

Vietnam is a major rice producer and much of the rice grown is concentrated in the Red River Delta (RRD) and the Mekong River Delta (MRD). While the two mega-deltas are highly productive regions, they are vulnerable to natural hazards and the effects of human related environmental change. The natural hazards that affect Vietnam include typhoons, floods and droughts while the major anthropogenic developments happening in Vietnam include dike development, sand mining, dam construction and groundwater extraction. Outbreaks of pests and diseases are also common. Although there is a substantial volume of work investigating the environmental impacts of these natural hazards and anthropogenic interventions, few studies have examined the implications of these on food security. To show that the processes and issues affecting food security are reinforcing and interdependent, we used a systems thinking approach to represent the ways in which natural hazards, anthropogenic land-use and climate change affect rice production in the two mega-deltas. A key finding is that anthropogenic developments meant to improve agricultural productivity or increase economic development create many unwanted environmental consequences such as an increase in flooding, saltwater intrusion and land subsidence which in turn create other negative feedbacks on rice production and quality. In addition, natural hazards may amplify the problems created by human activities. In future, besides creating new environmental threats, climate change may exacerbate the effects of natural hazards by increasing the frequency and severity of natural disasters. Our meta-analysis highlights the ways in which a systems thinking approach can yield more nuanced perspectives to tackle complex and interrelated environmental challenges. Given that mega-deltas worldwide are globally significant for food production and are highly stressed and degraded landscapes, a systems thinking approach can be applied to provide a holistic and contextualized overview of the threats faced in each location.

Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66% probability) GMSL rise of 0.30–0.65 m by 2100, and 0.54–2.15 m by 2300, relative to 1986–2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63–1.32 m by 2100, and 1.67–5.61 m by 2300. Expert projections for 2100 are similar to those from the original survey, although the projection for 2300 has extended tails and is higher than the original survey. Experts give a likelihood of 42% (original survey) and 45% (current survey) that under the high-emissions scenario GMSL rise will exceed the upper bound (0.98 m) of the likely range estimated by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, which is considered to have an exceedance likelihood of 17%. Responses to open-ended questions suggest that the increases in upper-end estimates and uncertainties arose from recent influential studies about the impact of marine ice cliff instability on the meltwater contribution to GMSL rise from the Antarctic Ice Sheet. Ministry of Education (MOE) National Research Foundation (NRF) Published version Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66% probability) GMSL rise of 0.30–0.65 m by 2100, and 0.54–2.15 m by 2300, relative to 1986–2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63–1.32 m by 2100, and 1.67–5.61 m by 2300. Expert projections for 2100 are similar to those from the original survey, although the projection for 2300 has extended tails and is higher than the original survey. Experts give a likelihood of 42% (original survey) and 45% (current survey) that under the high-emissions scenario GMSL rise will exceed the upper bound (0.98 m) of the likely range estimated by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, which is considered to have an exceedance likelihood of 17%. Responses to open-ended questions suggest that the increases in upper-end estimates and uncertainties arose from recent influential studies about the impact of marine ice cliff instability on the meltwater contribution to GMSL rise from the Antarctic Ice Sheet.

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%1 of the current global annual demand for vegetable oil as food, animal feed, and fuel (210 million tons2 (Mt)), but planted oil palm covers less than 5-5.5%3 of total global oil crop area (ca. 425 Mha)4 , due to oil palm’s relatively high yields5. 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 3% in West Africa to 47% in Malaysia. 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.\ud Over the past 25 years, global oil crops have expanded rapidly, with major impacts on land use. The land used for growing oil crops grew from 170 million ha (Mha) in 1961 to 425 Mha in 2017 or ~30% of all cropland world-wide. Oil palm, soy, and rapeseed together account for >80% of all vegetable oil production with cotton, groundnuts, sunflower, olive, and coconut comprising most of the remainder (Table 1, Figure 1). These crops, including soy (125 Mha planted area) and maize (197 Mha planted area), are also used as animal feed and other products.\ud Oil palm is the most rapidly expanding oil crop. This palm originates from equatorial Africa where it has been cultivated for millennia, but it is now widely grown in Southeast Asia. Between 2008 and 2017, oil palm expanded globally at an average rate of 0.7 Mha per year, and palm oil is the leading and cheapest edible oil in much of Asia and Africa. While it has been estimated that palm oil is an ingredient in 43% of products found in British supermarkets, we lack comparable studies for the prevalence of other oils.\ud As a wild plant, the oil palm is a colonising species that establishes in open areas. Cultivated palms are commonly planted as monocultures, although the tree is also used in mixed, small-scale and agroforestry settings. To maximize photosynthetic capacity and fruit yields, oil palm requires a warm and wet climate, high solar radiation, and high humidity. It is thus most productive in the humid tropics, while other oil crops, except coconut, grow primarily in subtropical and temperate regions (Table 1). Moreover, because oil palm tolerates many soils including deep peat and sandy substrates, it is often profitable in locations where few other commodity crops are viable. The highest yields from planted oil palm have been reported in Southeast Asia5 . Yields are generally lower in Africa and the Neotropics, likely reflecting differences in climatic conditions including humidity and cloud cover, as well as management, occurrence of pests and diseases, and planting stock.\ud Palm oil is controversial due to its social and environmental impacts and opportunities. Loss of natural habitats, reduction in woody biomass, and peatland drainage that occur during site preparation are the main direct environmental impacts from oil palm development. Such conversion typically reduces biodiversity and water quality and increases greenhouse gas emissions, and, when fire is used, smoke and haze. Industrial oil palm expansion by large multi-national and national companies is also often associated with social problems, such as land grabbing and conflicts, labour exploitation, social inequity16 and declines in village-level well-being. In producer countries, oil palm is a valued crop that brings economic development to regions with few alternative agricultural development options, and generates substantial average livelihood improvements when smallholder farmers adopt oil palm. Here we review the current understanding of the environmental impacts from oil palm cultivation and assess what we know about other oil crops in comparison. Our focus is on biodiversity implications and the environmental aspects of sustainability, and we acknowledge the importance of considering these alongside socio-cultural, political, and economic outcomes.

Environmental and social problems triggered by rapid palm oil expansion in the tropics have spurred the proliferation of sustainability certification systems such as the Roundtable on Sustainable Palm Oil (RSPO). While the RSPO aims to improve the impact of oil palm production on people and environments, its effect on local development, environmental quality, and, especially, potential trade-offs between these outcomes remain unclear. Here, we evaluate whether RSPO certification of large-scale industrial concessions has promoted village development and supported environmental quality in Indonesia, the top global palm oil producer. Using a panel dataset with observations from 11 000 villages in Kalimantan and Sumatra from 2003 to 2014, we apply rigorous quasi-experimental methods to quantify the RSPO's impacts on village development and environmental outcomes. In the short-run, RSPO contributed to environmental conservation, but had limited development outcomes. On average, relative to villages with non-certified concessions, RSPO certification reduced deforestation and protected primary forests in Sumatra and lowered the incidence of village-reported land pollution in Kalimantan. RSPO certification also increased the number of private educational facilities in Kalimantan, but had no statistically significant impacts on other development indicators. However, the trade-offs and complementarities between conservation and development vary by slope, a proxy for ecosystem fragility and oil palm profitability. On gentler slopes, we generally find complementarities between conservation and development outcomes. In Kalimantan, certification increased the number of private educational facilities and reduced deforestation and the incidence of land pollution on slopes < 2°. In Sumatra, certification retained more primary forests, decreased deforestation and the incidence of water pollution on slopes < 1°, along with a decrease in population density. Higher slopes in both locations were associated with environment and development trade-offs. We highlight the need to better understand the mechanisms behind the impacts of RSPO and emphasized how the outcomes of certification depend on the communities' bargaining power and the profitability of the land for oil palm production. Thus, we provide insights into understanding these mechanisms behind the impacts of RSPO, which is a prerequisite for improving the design of certification systems and their impacts on the ground. Ministry of Education (MOE) Published version JSHL acknowledges funding from the Singapore Ministry of Education Academic Research Fund Tier 1 RG145/19. OS acknowledges support of a NERC Doctoral Training Partnership grant (NE/S007407/1). KMC was supported by the NASA New (Early Career) Investigator Program in Earth Science (NNX16AI20G).

Changing human behavior is essential for biodiversity conservation, but robust approaches for large scale change are needed. Concepts like repeat message exposure and social reinforcement, as well as mechanisms like online news coverage and targeted advertisements, are currently used by private and public sectors, and could prove powerful for conservation. Thus, to explore their potential in influencing wildlife consumption, we used online advertisements through Facebook, Google, and Outbrain, to promote news articles discussing the use of a Critically Endangered antelope (the Saiga tatarica) as a traditional Chinese medicine in Singapore. Our message, tailored to middle‐aged Chinese Singaporean women, framed saiga horn products as being no longer socially endorsed. Through advert performance and in‐depth analyses of Facebook user engagement, we assessed audience response. Our message pervaded Singapore's online media (e.g., our adverts were shown almost five million times; and the story ran on seven news outlets), and resulted in widespread desirable audience responses (e.g., 63% of Facebook users' engagements included identifiably positive features like calls for public action to reduce saiga horn consumption, anger at having unknowingly used a Critically Endangered species, and self‐pledges to no longer use it; only 13% of engagements included identifiably negative features). This work shows that targeted dissemination of online news articles can have promising results, and may have wide applicability to conservation. Published version

Monitoring the expansion of commodity crops in the tropics is crucial to safeguard forests for biodiversity and ecosystem services. Oil palm (Elaeis guineensis) is one such crop that is a major driver of deforestation in Southeast Asia. We evaluated the use of a semi-automated approach with random forest as a classifier and combined optical and radar datasets to classify oil palm land-cover in 2015 in Sumatra, Indonesia, using Google Earth Engine. We compared our map with two existing remotely-sensed oil palm land-cover products that utilized visual and semi-automated approaches for the same year. We evaluated the accuracy of oil palm land-cover classification from optical (Landsat), radar (synthetic aperture radar (SAR)), and combined optical and radar satellite imagery (Combined). Combining Landsat and SAR data resulted in the highest overall classification accuracy (84%) and highest producer’s and user’s accuracy for oil palm classification (84% and 90%, respectively). The amount of oil palm land-cover in our Combined map was closer to official government statistics than the two existing land-cover products that used visual interpretation techniques. Our analysis of the extents of disagreement in oil palm land-cover indicated that our map had comparable accuracy to one of them and higher accuracy than the other. Our results demonstrate that a combination of optical and radar data outperforms the use of optical-only or radar-only datasets for oil palm classification and that our technique of preprocessing and classifying combined optical and radar data in the Google Earth Engine can be applied to accurately monitor oil-palm land-cover in Southeast Asia. Ministry of Education (MOE) Published version This research was funded by Singapore Ministry of Education Academic Research Fund Tier 1 grant number RG146/16.

Minimizing the negative impacts of tropical agricultural expansion and intensification on biodiversity and food security has been intensively discussed in the context of the land-sparing/land-sharing framework. Here, we evaluate how study scope, methodologies, geographical focus, number of species studied, and type of cropping system helped to shape authors’ recommendations. First, we found that empirical studies focusing on tropical biodiversity were primarily in favor of land sparing (67%, 12 of 18 studies), whereas reviews and perspectives with a non-biodiversity focus (e.g. ecosystem services and food security) were more likely to favor of land sharing (58%, 7 of 12 studies). Second, wildlife-friendly tree crops or shaded systems (e.g. coffee and cacao) were the focus of most applied ecology research, while annual crops accounted for the majority of tropical cropland area and recent expansion. While these trends lend support that land sparing—by closing yield gaps paired with the protection of large contiguous habitats—is favored to limit the impacts on sensitive tropical forest biodiversity, the necessary policies and enforcement mechanisms may not yet be present or effective, nor is there adequate understanding and mitigation of negative food security impacts. By illustrating how a study's context shapes recommendations, our results help move the land-sparing/land-sharing debate forward by clarifying the origins of long-standing disagreements.

In order to address sustainability challenges, we posit that knowledge generation needs to move rapidly from a disciplinary linear ‘tree’ model to an interdisciplinary ‘web’ model. We show how such a shift is useful by looking at case studies in the context of water management.

The wildlife trade is now one of the greatest threats to biodiversity, and birds are among the most commonly traded groups worldwide. The demand for pet birds is especially high in Indonesia, a country with many exploited, imperiled bird species. Finding solutions to the threat that trade poses for birds, and wildlife in general, requires an understanding of its socioeconomic dimensions. We examined consumer demography and preferences of 762 bird owners in Medan, Sumatra, focusing on the differences among owners of birds taken from the wild versus birds bred in captivity. We found that the vast majority of bird owners have at least one wild-caught bird. However, wild-caught bird ownership is not uniformly distributed across Medan; rather, there are distinct hotspots with high proportions of people with wild-caught birds. The main reasons for owning wild-caught birds are lack of access to and the high cost of captive-bred birds, and a perception that captive-bred birds do not sing as well as wild-caught ones. We conclude that captive-breeding programs could reduce the pressure on wild populations, especially if suppliers are able to produce relatively cheap captive-bred birds. However, the perceived poorer song quality of captive-bred individuals might be a problem for the captive breeding of some species, notably the White-rumped Shama, Copsychus malabaricus. Since many owners of this species compete in bird song competitions, establishing competition categories specifically for captive-bred shamas could promote captive-bred bird ownership. Tackling the problem of the wild bird trade in Indonesia and elsewhere will require consideration of both the economic and the social factors that underlie pet ownership.

Key findings-19% of individuals interviewed stated saiga was a product they use most often, to treat heatiness or fever in themselves or others.-Saiga users were significantly more likely to be aged 36-59 years old and to identify as Buddhist or Taoist.-47% of individuals who use saiga themselves also buy it for someone else.-Women aged 35-59 years old were significantly more likely to purchase saiga for someone else.-Saiga ‘cooling water’ was the most commonly preferred product form.-Saiga users were significantly more likely than non- saiga users to think that saiga was common in the wild.

Southeast (SE) Asia holds high regional biodiversity and endemism levels but is also one of the world's most threatened regions. Local, regional and global threats could have severe consequences for the future survival of many species and the provision of ecosystem services. In the face of myriad pressing environmental problems, we carried out a research prioritisation exercise involving 64 experts whose research relates to conservation biology and sustainability in SE Asia. Experts proposed the most pressing research questions which, if answered, would advance the goals of biodiversity conservation and sustainable development in SE Asia. We received a total of 333 questions through three rounds of elicitation, ranked them (by votes) following a workshop and grouped them into themes. The top 100 questions depict SE Asia as a region where strong pressures on biodiversity interact in complex and poorly understood ways. They point to a lack of information about multiple facets of the environment, while exposing the many threats to biodiversity and human wellbeing. The themes that emerged indicate the need to evaluate specific drivers of biodiversity loss (wildlife harvesting, agricultural expansion, climate change, infrastructure development, pollution) and even to identify which species and habitats are most at risk. They also suggest the need to study the effectiveness of practice-based solutions (protected areas, ecological restoration), the human dimension (social interventions, organisational systems and processes and, the impacts of biodiversity loss and conservation interventions on people). Finally, they highlight gaps in fundamental knowledge of ecosystem function. These 100 questions should help prioritise and coordinate research, conservation, education and outreach activities and the distribution of scarce conservation resources in SE Asia. Accepted version The workshop was funded by a generous donation from Haiyi Holdings Pte Ltd. to the Department of Biological Sciences of the National University of Singapore.

Unsustainable wildlife trade is a pervasive issue affecting wildlife globally. To address this issue, a plethora of demand reduction efforts have been carried out. These necessitate consumer research which provides crucial knowledge for designing and evaluating targeted interventions. We implemented a rigorous consumer survey on saiga (Saiga tatarica) horn use in Singapore, where usage is legal and widely sold. Saiga are Critically Endangered antelopes from Central Asia with horns (often marketed as ling yang) used in traditional Chinese medicine (TCM). Few past studies have assessed saiga horn consumers. This work is the most extensive consumer research to date specifically characterising saiga horn consumers and usage. We conducted 2294 in-person surveys on saiga horn use with Chinese Singaporeans, employing neutral questioning approaches. We found 19% of individuals reported saiga horn as a product they choose most often for themselves and/or others when treating fever and/or heatiness (a TCM state of illness), indicating a minimum estimate of high-frequency usage, not including possible low-frequency users. Overall saiga users were most characterised as middle-aged Buddhists and Taoists. However, saiga users were found in a range of demographic groups. Women preferred saiga shavings (the more traditional form), while men preferred saiga cooling water (the more modern form). About 53% of individuals who used saiga horn themselves also bought it for someone else. Buyers for others were most likely to be female middle-aged Buddhists or Taoists. Key motivating reasons for usage were "it works" and "someone recommended it to me." The top two reported recommenders were family and TCM shopkeepers. Saiga users were more likely than non-saiga users to perceive saiga as a common species in the wild. This research holds significance for interventions targeting saiga horn consumption within Singapore and throughout Asia, by identifying potential target audiences, product types, non-desirable alternatives, and motivations for use. Published version

[This corrects the article DOI: 10.1371/journal.pone.0222038.].

Addressing transboundary environmental problems, such as pollution, and climate change, hinge on strategies that often require both mandatory and voluntary participation of affected nations. Using an unprecedented approach, the Singapore government recently passed a Transboundary Haze Pollution Act (THPA) that financially penalizes companies for smoke-haze affecting the city-state but originating from activities outside her political boundaries. This Act may set a precedent for future actions against proximate actors of environmental degradation but is fraught with substantial challenges in implementation. In attempting to hold agri-business companies accountable, the THPA must present indisputable evidence of fire burning activities and positively identify the initiator of these fires. We further argue that small amendments to the THPA, and other similar laws, may result in environmental co-benefits related to carbon emissions, ecosystem services and biodiversity preservation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Tropical deforestation in Southeast Asia is one of the leading causes of carbon emissions and reductions of biodiversity. Spatially explicit analyses of the dynamics of deforestation in Indonesia are needed to support sustainable land use planning but the value of such analyses has so far been limited by data availability and geographical scope. We use remote sensing maps of land use change from 2000 to 2010 to compare Bayesian computational models: autologistic and von Thunen spatial-autoregressive models. We use the models to analyze deforestation patterns in Indonesia and the effectiveness of protected areas. Cross-validation indicated that models had an accuracy of 70–85%. We find that the spatial pattern of deforestation is explained by transport cost, agricultural rent and history of nearby illegal logging. The effectiveness of protected areas presented mixed results. After controlling for multiple confounders, protected areas of category Ia , exclusively managed for biodiversity conservation, were shown to be ineffective at slowing down deforestation. Our results suggest that monitoring and prevention of road construction within protected areas, using logging concessions as buffers of protected areas and geographical prioritization of control measures in illegal logging hotspots would be more effective for conservation than reliance on protected areas alone, especially under food price increasing scenarios.

The first International Peat Congress (IPC) held in the tropics – in Kuching (Malaysia) – brought together over 1000 international peatland scientists and industrial partners from across the world (“International Peat Congress with over 1000 participants!,” 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat.

The effectiveness of land-sharing and land-sparing approaches has been widely debated. Yet, few studies quantify the environmental and socio-economic outcomes of these approaches within a real-world landscape. Indonesia's plans to increase its palm oil production present an opportunity to investigate the potential environmental and socio-economic implications of the land-sharing and sparing approaches.We developed a computer model to simulate the expansion of oil palm agriculture in Sumatra, Indonesia, under four different scenarios distinguishable by the dominance of scheme smallholders or industrial estates: business-as-usual, BAU (25 : 75, scheme smallholders:industrial estates); high-yielding industry dominated, ESTATE (10 : 90); low-yielding smallholder dominated, SMALLHOLDER (40 : 60), high-yielding smallholder dominated, HYBRID (40 : 60; but with improved smallholder yields).Our results reveal several trade-offs associated with varying the proportion of scheme smallholders and productivity of oil palm plantations. The ESTATE scenario (reflecting land-sparing) resulted in lowest environmental costs in terms of forest conversion, greenhouse gas emissions, biodiversity losses and nitrogen fertilizer usage. Additionally, infrastructural development and tax revenues were highest under the land-sparing approach, though fewer jobs were created. The SMALLHOLDER scenario (indicating land-sharing) resulted in highest environmental costs in terms of forest conversion, carbon dioxide emissions and biodiversity losses but involved more households in oil palm agriculture and thus created more employment opportunities. The HYBRID scenario ranked second best in terms of both minimizing forest loss and job creation. However, the drawbacks of this approach included high nitrogen fertilizer consumption, lower infrastructural development and lower tax revenues.

Indonesia contributes significantly to deforestation in Southeast Asia. However, much uncertainty remains over the relative contributions of various forest-exploiting sectors to forest losses in the country. Here, we compare the magnitudes of forest and carbon loss, and forest and carbon stocks remaining within oil palm plantation, logging, fiber plantation (pulp and paper), and coal mining concessions in Indonesia. Forest loss in all industrial concessions, including logging concessions, relate to the conversion of forest to nonforest land cover. We found that the four industries accounted for ∼44.7% (∼6.6 Mha) of forest loss in Kalimantan, Sumatra, Papua, Sulawesi, and Moluccas between 2000 and 2010. Fiber plantation and logging concessions accounted for the largest forest loss (∼1.9 Mha and ∼1.8 Mha, respectively). Although the oil palm industry is often highlighted as a major driver of deforestation, it was ranked third in terms of deforestation (∼1 Mha), and second in terms of carbon dioxide emissions (∼1,300–2,350 Mt CO2). Crucially, ∼34.6% (∼26.8 Mha) of Indonesia's remaining forests is located within industrial concessions, the majority of which is found within logging concessions (∼18.8 Mha). Hence, future development plans within Indonesia's industrial sectors weigh heavily on the fate of Southeast Asia's remaining forests and carbon stocks.

Environment Institute and School of Earth and EnvironmentalSciences, University of Adelaide, Adelaide, SA 5005, AustraliaSummaryExpansion of oil palm plantations has led to extensive wild-life habitat conversion in Southeast Asia [1]. This expansionis driven by a global demand for palm oil for productsranging from foods to detergents [2], and more recently forbiofuels [3]. The negative impacts of oil palm developmenton biodiversity [1, 4, 5], and on orangutans (Pongo spp.) inparticular, have been well documented [6, 7] and publicized[8, 9]. Although the oil palm is of African origin, Africa’sproduction historically lags behind that of Southeast Asia.Recently, significant investments have been made that willlikely drive the expansion of Africa’s oil palm industry [10].There is concern that this will lead to biodiversity lossessimilar to those in Southeast Asia. Here, we analyze thepotential impact of oil palm development on Africa’s greatapes. Current great ape distribution in Africa substantiallyoverlaps with current oil palm concessions (by 58.7%) andareas suitable for oil palm production (by 42.3%). Moreimportantly, 39.9% of the distribution of great ape specieson unprotected lands overlaps with suitable oil palm areas.There is an urgent need to develop guidelines for the expan-sion of oil palm in Africa to minimize the negative effects onapes and other wildlife. There is also a need for researchto support land use decisions to reconcile economic devel-opment, great ape conservation, and avoiding carbonemissions.ResultsOil Palm Threat to Known Great Ape DistributionCurrent oil palm concessions for which spatial data are avail-able show a 58.7% 6 53.3% (6SD; all 6% data show 6SD)overlap with the distribution of great ape species in Africa(see Table S1 available online). Potential future oil palm devel-opment among African countries, as indicated by the percent-ageoflandsuitableforoilpalmproduction,rangesfrom0%forBurkina Faso, Mali, Rwanda, and South Sudan to 96.6% forLiberia (mean = 32.2% 6 31.9%; Table S2; Figure 1). Onaverage, the amount of overlap between the current distribu-tions of great ape species and suitable oil palm area is42.3% 6 38.4%, ranging from 0.5% in Tanzania to 100% inGhana.Large parts of great ape habitats are not protected and aresuitable for oil palm (Table S2; Figure 1). The mean countryoverlap between areas of known African ape species distribu-tion that are not protected and areas suitable for oil palm is39.9% 6 36.8%, whereas the mean percentage of Africanape species distribution that is not suitable for oil palm andis not protected is 49.8% 6 34.5%. The mean percentage ofAfrican ape species habitat that is protected under IUCNcategory II is 10.3% 6 13.1% (Table S2; Figure 1).Not all great ape species are equally threatened by oil palmdevelopment (Table S3; Figure 2). The amount of overlapbetween species distribution and suitable oil palm area is10.7% 6 18.5% for Gorilla beringei, 41.7% 6 37.9% for Pantroglodytes, 73.8% 6 16.8% for G. gorilla, and 99.2% forP. paniscus. Species that are most threatened by future oilpalm development also have some of the smallest extentsof their current distribution under protection: G. gorilla(11.2% 6 14.4%), P. troglodytes (10.2% 6 12.5%), andP. paniscus (8.0%). The percentage of distribution that is notsuitable for oil palm and at the same time not protected alsovaries across species, being highest for P. troglodytes(50.4% 6 33.9%) and lowest for G. beringei (17.6% 625.0%). We also quantified the overlap between the distribu-tion of great ape species and suitable oil palm areas withinprotected areas (Table S4). For all species combined, thisrepresents 2.4% 6 2.9%, ranging from 1.4% 6 2.4% forG. beringei to 8.7% 6 13.4% for G. gorilla (Table S4).Oil Palm Threat to Suitable Environmental Conditions forAfrican Great Ape SpeciesInall countries where great ape species predominantly inhabitrainforests, a large proportion of land containing sustainableenvironmental conditions (SEC) for these species overlapswith suitable oil palm areas (Figure 3; Table S5). This is thecase for Sierra Leone (48.8%), Liberia (81.7%), Coˆte d’Ivoire(59.6%), and Ghana (87.9%) in West Africa, and for all CentralAfrican countries containing great apes (49.5%). For some ofthe countries, such as Liberia and Republic of the Congo,more than three-quarters of great ape SEC overlaps withsuitable oil palm areas. In East Africa and countries at therange limits of ape species in West Africa, suitable oil palmareas cover much smaller proportions of SEC (