Proceedings of the National Academy of Sciences, 2024
Uncontrolled fires place considerable burdens on forest ecosystems, compromising our ability to m... more Uncontrolled fires place considerable burdens on forest ecosystems, compromising our ability to meet conservation and restoration goals. A poor understanding of the impacts of fire on ecosystems and their biodiversity exacerbates this challenge, particularly in tropical regions where few studies have applied consistent analytical techniques to examine a broad range of ecological impacts over multiyear time frames. We compiled 16 y of data on ecosystem properties (17 variables) and biodiversity (21 variables) from a tropical peatland in Indonesia to assess fire impacts and infer the potential for recovery. Burned forest experienced altered structural and microclimatic conditions, resulting in a proliferation of nonforest vegetation and erosion of forest ecosystem properties and biodiversity. Compared to unburned forest, habitat structure, tree density, and canopy cover deteriorated by 58 to 98%, while declines in species diversity and abundance were most pronounced for trees, damselflies, and butterflies, particularly for forest specialist species. Tracking ecosystem property and biodiversity datasets over time revealed most to be sensitive to recurrent high-intensity fires within the wider landscape. These megafires immediately compromised water quality and tree reproductive phenology, crashing commercially valuable fish populations within 3 mo and driving a gradual decline in threatened vertebrates over 9 mo. Burned forest remained structurally compromised long after a burn event, but vegetation showed some signs of recovery over a 12-y period. Our findings demonstrate that, if left uncontrolled, fire may be a pervasive threat to the ecological functioning of tropical forests, underscoring the importance of fire prevention and long-term restoration efforts, as exemplified in Indonesia.
Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major... more Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major contributor to carbon emissions globally. Being subterranean, these fires can be difficult to detect and track, especially during periods of thick haze and in areas with limited accessibility. Thermal infrared detectors mounted on drones present a potential solution to detecting and managing underground fires, as they allow large areas to be surveyed quickly from above and can detect the heat transferred to the surface above a fire. We present a pilot study in which we show that underground peat fires can indeed be detected in this way. We also show that a simple temperature thresholding algorithm can be used to automatically detect them. We investigate how different thermal cameras and drone flying strategies may be used to reliably detect underground fires and survey fire-prone areas. We conclude that thermal equipped drones are potentially a very powerful tool for surveying for fires and firefighting. However, more investigation is still needed into their use in real-life fire detection and firefighting scenarios.
Southeast Asia's tropical peat-swamp forests (TPSF) are globally important for carbon storage... more Southeast Asia's tropical peat-swamp forests (TPSF) are globally important for carbon storage and biodiversity conservation, but are at risk from multiple threats and urgently require improved management. Ants are often used as ecological indicators in monitoring programmes to guide adaptive management, but data on TPSF ants are scarce. We conducted a twelve-month study on ants in the Sabangau TPSF in Indonesian Borneo using baited traps, to compare community composition across three disturbance categories (forest gaps, forest edge and relatively undisturbed interior forest) and between dry and wet season. The three disturbance categories supported distinct ant communities across seasons. Differences in canopy cover likely underlie these changes in ant community composition. Surveying was more effective in the dry season, because ant capture rates were higher and more indicator taxa were identified than in the wet season, but overall ant community composition did not differ sign...
We thank the Indonesian Ministry of Research and Technology (RISTEK) and UPT LLG CIMTROP UPR for ... more We thank the Indonesian Ministry of Research and Technology (RISTEK) and UPT LLG CIMTROP UPR for research permissions in the NLPSF. Collection of the species records described here has been made possible through financial support from a large number of sources over the years, among which we are particularly indebted to The Orangutan Project, Arcus Foundation, US Fish & Wildlife Service Great Apes Conservation Fund, the StOLT fund of SaveTheOrangutan and the Orangutan Land Trust, Orangutan Appeal UK, EAZA, Bioparcs Foundation, Orangutan Outreach, Orangutan Conservancy, Taronga Zoo, Riverbanks Zoo, Wallace Global Fund, Ocean Parks Conservation Foundation Hong Kong, Wildlife Conservation Society, Primate Conservation Inc., IFAW, Karen Hanssen Trust, the Rufford Foundation, Point Defiance Zoo and Aquarium, Clouded Leopard Project, Fresno Chafee Zoo, and Panthera and Robertson Foundation (through WildCRU, University of Oxford). A large number of staff, students, volunteers and other visi...
Southeast Asia’s tropical peat-swamp forests (PSFs) are important for biodiversity conservation, ... more Southeast Asia’s tropical peat-swamp forests (PSFs) are important for biodiversity conservation, but decades of peat mis-management, illegal logging and largely unrestricted agricultural development in Kalimantan has led to peat drainage in most areas and consequent fire vulnerability. This was highlighted in 2015, when a strong El Niño event led to extensive peatland fires, which reached their peak during August to October 2015. Thousands of square kilometres of peatland were burned, including fires in/around such important PSFs as Sabangau, Mawas, Katingan and Tanjung Puting. We consider the potential impacts of these fires on Kalimantan’s biodiversity. The huge majority of PSF fauna species will have been negatively impacted, owing to (1) forest area/habitat loss, including destruction of entire smaller forest fragments; (2) toxic haze inhalation; (3) impacts of drought and low sunlight on forest trees; and (4) increased river acidity. Less mobile, longer-lived and slower-breedin...
Conservation projects are likely to fail if plans to preserve important wildlife habitats and spe... more Conservation projects are likely to fail if plans to preserve important wildlife habitats and species are not co-developed between conservation organisations and local communities to reflect the needs and diverse values of the latter. Tropical peatland conservation represents a case in point: local community livelihoods have only recently come into focus, particularly within academic literature. Instead, many previous studies emphasise the need to conserve intact peat swamp forests for their carbon storage, as a habitat for flagship species such as the orangutan, and to provide fire-free landscapes. Here, we explore the socio-environmental issues being faced in the peatland landscapes of Central Kalimantan, Indonesia. This includes the loss of peat-swamp forest, decreases in peatland fish populations and related socio-cultural challenges such as potential loss of fishing livelihoods along with historic and continued experiences of marginalisation of indigenous communities. To find solutions to these complex and interrelated problems, an interdisciplinary approach which focuses on interdependencies and includes multiple worldviews is required. We propose an approach which deploys both Ethan Miller's use of livelihoods (incl. Miller, 2019) and biocultural approaches to conservation to analyse human-nonhuman relationships, with a focus on fish and fishing livelihoods. We draw on data from in-depth social and ecological research in two village communities in Central Kalimantan, and in so doing illustrate how fish conservation has the potential to support important biocultural and livelihood relationships between human and nonhuman communities in peatland areas. Our findings lend support to previous calls for biocultural approaches to conservation in other socio-ecological contexts, and lead us to conclude that tropical peatland conservation initiatives that integrate such approaches will result in improved outcomes for peatlands, forests, biodiversity and people. These findings will be relevant to other tropical peatland areas with high dependence on fishing as a source of livelihood, such as the peatlands of the Amazon and Congo basins.
As the COVID‐19 pandemic continues to affect societies across the world, the ongoing economic and... more As the COVID‐19 pandemic continues to affect societies across the world, the ongoing economic and social disruptions are likely to present fundamental challenges for current and future biodiversity conservation. We review the literature for outcomes of past major societal, political, economic and zoonotic perturbations on biodiversity conservation, and demonstrate the complex implications of perturbation events upon conservation efforts. Building on the review findings, we use six in‐depth case studies and the emerging literature to identify positive and negative outcomes of the COVID‐19 pandemic, known and anticipated, for biodiversity conservation efforts around the world. A number of similarities exist between the current pandemic and past perturbations, with experiences highlighting that the pandemic‐induced declines in conservation revenue and capacity, livelihood and trade disruptions are likely to have long‐lasting and negative implications for biodiversity and conservation e...
Peatlands are highly dynamic systems, able to accumulate carbon over millennia under natural cond... more Peatlands are highly dynamic systems, able to accumulate carbon over millennia under natural conditions, but susceptible to rapid subsidence and carbon loss when drained. Short-term, seasonal and long-term peat surface elevation changes are closely linked to key peatland attributes such as water table depth (WTD) and carbon balance, and may be measured remotely using satellite radar and LiDAR methods. However, field measurements of peat elevation change are spatially and temporally sparse, reliant on low-resolution manual subsidence pole measurements, or expensive sensor systems. Here we describe a novel, simple and low-cost image-based method for measuring peat surface motion and WTD using commercially available time-lapse cameras and image processing methods. Based on almost two years’ deployment of peat cameras across contrasting forested, burned, agricultural and oil palm plantation sites in Central Kalimantan, Indonesia, we show that the method can capture extremely high resolu...
The COVID-19 pandemic has caused global disruption, with the emergence of this and other pandemic... more The COVID-19 pandemic has caused global disruption, with the emergence of this and other pandemics having been linked to habitat encroachment and/or wildlife exploitation. High impacts of COVID-19 are apparent in some countries with large tropical peatland areas, some of which are relatively poorly resourced to tackle disease pandemics. Despite this, no previous investigation has considered tropical peatlands in the context of emerging infectious diseases (EIDs). Here, we review: (i) the potential for future EIDs arising from tropical peatlands; (ii) potential threats to tropical peatland conservation and local communities from COVID-19; and (iii) potential steps to help mitigate these risks. We find that high biodiversity in tropical peat-swamp forests, including presence of many potential vertebrate and invertebrate vectors, combined, in places, with high levels of habitat disruption and wildlife harvesting represent suitable conditions for potential zoonotic EID (re-)emergence. A...
Tropical forests and peatlands provide important ecological, climate and socio‐economic benefits ... more Tropical forests and peatlands provide important ecological, climate and socio‐economic benefits from the local to the global scale. However, these ecosystems and their associated benefits are threatened by anthropogenic activities, including agricultural conversion, timber harvesting, peatland drainage and associated fire. Here, we identify key challenges, and provide potential solutions and future directions to meet forest and peatland conservation and restoration goals in Indonesia, with a particular focus on Kalimantan. Through a round‐table, dual‐language workshop discussion and literature evaluation, we recognized 59 political, economic, legal, social, logistical and research challenges, for which five key underlying factors were identified. These challenges relate to the 3Rs adopted by the Indonesian Peatland Restoration Agency (Rewetting, Revegetation and Revitalization), plus a fourth R that we suggest is essential to incorporate into (peatland) conservation planning: Reduc...
Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major... more Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major contributor to carbon emissions globally. Being subterranean, these fires can be difficult to detect and track, especially during periods of thick haze and in areas with limited accessibility. Thermal infrared detectors mounted on drones present a potential solution to detecting and managing underground fires, as they allow large areas to be surveyed quickly from above and can detect the heat transferred to the surface above a fire. We present a pilot study in which we show that underground peat fires can indeed be detected in this way. We also show that a simple temperature thresholding algorithm can be used to automatically detect them. We investigate how different thermal cameras and drone flying strategies may be used to reliably detect underground fires and survey fire-prone areas. We conclude that thermal equipped drones are potentially a very powerful tool for surveying for fires...
The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought... more 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…
Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian populati... more Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian population density. Studies relating habitat quality to population density have typically made comparisons among distant species or communities without considering variation in food quality among localities. We compared dietary nutritional quality of two Bornean orangutan populations with differing population densities in peatland habitats, Tuanan and Sabangau, separated by 63 km. We hypothesized that because Tuanan is alluvial, the plant species included in the orangutan diet would be of higher nutritional quality compared to Sabangau, resulting in higher daily caloric intake in Tuanan. We also predicted that forest productivity would be greater in Tuanan compared to Sabangau. In support of these hypotheses, the overall quality of the diet and the quality of matched dietary items were higher in Tuanan, resulting in higher daily caloric intake compared to Sabangau. These differences in dietary nutritional quality may provide insights into why orangutan population density is almost two times greater in Tuanan compared to Sabangau, in agreement with a potentially important influence of diet quality on primate population density.
The timing and frequency of flowering and fruiting events are key tropical forest characteristics... more The timing and frequency of flowering and fruiting events are key tropical forest characteristics that have substantial influence on fauna. Although our understanding of geographic variation in habitat‐wide timing and frequency of flowering and fruiting is advancing, corresponding information for individual tree species is limited. Thus, we compared climate and reproductive phenology of 16 tree species over 70 mo at two Bornean tropical peat‐swamp forest sites. We found significant inter‐site correlations in rainfall and temperature, and only small absolute temperature differences. In both sites, most species exhibited within‐site synchrony in flowering and fruiting onset. Broad‐scale flowering and fruiting onset frequency classifications showed high congruence between sites. Significant correlations in flowering and fruiting onset timing between sites were found for only 19 and 17 percent of the species, respectively. This remained the case when applying 1‐ and 2‐month lag periods ...
Key to the subfamilies of ants This key is a simplified version of Bolton (1994), filtered only t... more Key to the subfamilies of ants This key is a simplified version of Bolton (1994), filtered only to include subfamilies that have been recorded in the Southeast-Asian region. Subfamilies marked with * have been recorded in the Sabangau or Kalampangan forests.
The orangutan is the world's largest arboreal mammal, and images of the red ape moving throug... more The orangutan is the world's largest arboreal mammal, and images of the red ape moving through the tropical forest canopy symbolise its typical arboreal behaviour. Records of terrestrial behaviour are scarce and often associated with habitat disturbance. We conducted a large-scale species-level analysis of ground-based camera-trapping data to evaluate the extent to which Bornean orangutans Pongo pygmaeus come down from the trees to travel terrestrially, and whether they are indeed forced to the ground primarily by anthropogenic forest disturbances. Although the degree of forest disturbance and canopy gap size influenced terrestriality, orangutans were recorded on the ground as frequently in heavily degraded habitats as in primary forests. Furthermore, all age-sex classes were recorded on the ground (flanged males more often). This suggests that terrestrial locomotion is part of the Bornean orangutan's natural behavioural repertoire to a much greater extent than previously th...
Pteropus vampyrus natunae, the Bornean subspecies of the large flying fox, has important roles in... more Pteropus vampyrus natunae, the Bornean subspecies of the large flying fox, has important roles in pollination but unsustainable hunting has been reported in Malaysian states. We provide the first description of hunting techniques and intensity in Indonesian Borneo. In forests around Palangka Raya this species is captured in canopy-level nets to support trade in the provincial capital. We estimate that in 2003 4,500 individuals were extracted from a single location in 30 days, which, together with trends reported in interviews with hunters and traders, suggests that hunting in this region is intensive and probably causing severe population declines. Further surveys are needed throughout Kalimantan to determine if this trend is occurring around other cities and whether intervention is needed to safeguard viable populations.
Orang-utans (Pongo spp.) are primarily frugivorous (Morrogh-Bernard et al. 2009) and are often re... more Orang-utans (Pongo spp.) are primarily frugivorous (Morrogh-Bernard et al. 2009) and are often regarded as important seed dispersers (Corlett 1998). In Tanjung Puting, Borneo, Galdikas (1982) found intact seeds in 94% of faecal samples, with a median 111 seeds per defecation; and in Ketambe, Sumatra, Rijksen (1978) found seeds in 44% of faecal samples. Furthermore, orang-utans have large day ranges (e.g. mean = 968 m, range = 280–2834 m across adults in Sabangau; Harrison 2009) and slow passage rates of digesta through the gut (Caton et al. 1999), and, hence, may disperse seeds far from parent trees. Many seeds are also spat out or discarded at distances up to 75 m from parent trees (Galdikas 1982).
Here, we show how the mechanical properties of a thick-shelled tropical seed are adapted to permi... more Here, we show how the mechanical properties of a thick-shelled tropical seed are adapted to permit them to germinate while preventing their predation. The seed has evolved a complex heterogeneous microstructure resulting in hardness, stiffness and fracture toughness values that place the structure at the intersection of these competing selective constraints. Analyses of different damage mechanisms inflicted by beetles, squirrels and orangutans illustrate that cellular shapes and orientations ensure damage resistance to predation forces imposed across a broad range of length scales. This resistance is shown to be around the upper limit that allows cracking the shell via internal turgor pressure (i.e. germination). Thus, the seed appears to strike an exquisitely delicate adaptive balance between multiple selection pressures.
Proceedings of the National Academy of Sciences, 2024
Uncontrolled fires place considerable burdens on forest ecosystems, compromising our ability to m... more Uncontrolled fires place considerable burdens on forest ecosystems, compromising our ability to meet conservation and restoration goals. A poor understanding of the impacts of fire on ecosystems and their biodiversity exacerbates this challenge, particularly in tropical regions where few studies have applied consistent analytical techniques to examine a broad range of ecological impacts over multiyear time frames. We compiled 16 y of data on ecosystem properties (17 variables) and biodiversity (21 variables) from a tropical peatland in Indonesia to assess fire impacts and infer the potential for recovery. Burned forest experienced altered structural and microclimatic conditions, resulting in a proliferation of nonforest vegetation and erosion of forest ecosystem properties and biodiversity. Compared to unburned forest, habitat structure, tree density, and canopy cover deteriorated by 58 to 98%, while declines in species diversity and abundance were most pronounced for trees, damselflies, and butterflies, particularly for forest specialist species. Tracking ecosystem property and biodiversity datasets over time revealed most to be sensitive to recurrent high-intensity fires within the wider landscape. These megafires immediately compromised water quality and tree reproductive phenology, crashing commercially valuable fish populations within 3 mo and driving a gradual decline in threatened vertebrates over 9 mo. Burned forest remained structurally compromised long after a burn event, but vegetation showed some signs of recovery over a 12-y period. Our findings demonstrate that, if left uncontrolled, fire may be a pervasive threat to the ecological functioning of tropical forests, underscoring the importance of fire prevention and long-term restoration efforts, as exemplified in Indonesia.
Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major... more Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major contributor to carbon emissions globally. Being subterranean, these fires can be difficult to detect and track, especially during periods of thick haze and in areas with limited accessibility. Thermal infrared detectors mounted on drones present a potential solution to detecting and managing underground fires, as they allow large areas to be surveyed quickly from above and can detect the heat transferred to the surface above a fire. We present a pilot study in which we show that underground peat fires can indeed be detected in this way. We also show that a simple temperature thresholding algorithm can be used to automatically detect them. We investigate how different thermal cameras and drone flying strategies may be used to reliably detect underground fires and survey fire-prone areas. We conclude that thermal equipped drones are potentially a very powerful tool for surveying for fires and firefighting. However, more investigation is still needed into their use in real-life fire detection and firefighting scenarios.
Southeast Asia's tropical peat-swamp forests (TPSF) are globally important for carbon storage... more Southeast Asia's tropical peat-swamp forests (TPSF) are globally important for carbon storage and biodiversity conservation, but are at risk from multiple threats and urgently require improved management. Ants are often used as ecological indicators in monitoring programmes to guide adaptive management, but data on TPSF ants are scarce. We conducted a twelve-month study on ants in the Sabangau TPSF in Indonesian Borneo using baited traps, to compare community composition across three disturbance categories (forest gaps, forest edge and relatively undisturbed interior forest) and between dry and wet season. The three disturbance categories supported distinct ant communities across seasons. Differences in canopy cover likely underlie these changes in ant community composition. Surveying was more effective in the dry season, because ant capture rates were higher and more indicator taxa were identified than in the wet season, but overall ant community composition did not differ sign...
We thank the Indonesian Ministry of Research and Technology (RISTEK) and UPT LLG CIMTROP UPR for ... more We thank the Indonesian Ministry of Research and Technology (RISTEK) and UPT LLG CIMTROP UPR for research permissions in the NLPSF. Collection of the species records described here has been made possible through financial support from a large number of sources over the years, among which we are particularly indebted to The Orangutan Project, Arcus Foundation, US Fish & Wildlife Service Great Apes Conservation Fund, the StOLT fund of SaveTheOrangutan and the Orangutan Land Trust, Orangutan Appeal UK, EAZA, Bioparcs Foundation, Orangutan Outreach, Orangutan Conservancy, Taronga Zoo, Riverbanks Zoo, Wallace Global Fund, Ocean Parks Conservation Foundation Hong Kong, Wildlife Conservation Society, Primate Conservation Inc., IFAW, Karen Hanssen Trust, the Rufford Foundation, Point Defiance Zoo and Aquarium, Clouded Leopard Project, Fresno Chafee Zoo, and Panthera and Robertson Foundation (through WildCRU, University of Oxford). A large number of staff, students, volunteers and other visi...
Southeast Asia’s tropical peat-swamp forests (PSFs) are important for biodiversity conservation, ... more Southeast Asia’s tropical peat-swamp forests (PSFs) are important for biodiversity conservation, but decades of peat mis-management, illegal logging and largely unrestricted agricultural development in Kalimantan has led to peat drainage in most areas and consequent fire vulnerability. This was highlighted in 2015, when a strong El Niño event led to extensive peatland fires, which reached their peak during August to October 2015. Thousands of square kilometres of peatland were burned, including fires in/around such important PSFs as Sabangau, Mawas, Katingan and Tanjung Puting. We consider the potential impacts of these fires on Kalimantan’s biodiversity. The huge majority of PSF fauna species will have been negatively impacted, owing to (1) forest area/habitat loss, including destruction of entire smaller forest fragments; (2) toxic haze inhalation; (3) impacts of drought and low sunlight on forest trees; and (4) increased river acidity. Less mobile, longer-lived and slower-breedin...
Conservation projects are likely to fail if plans to preserve important wildlife habitats and spe... more Conservation projects are likely to fail if plans to preserve important wildlife habitats and species are not co-developed between conservation organisations and local communities to reflect the needs and diverse values of the latter. Tropical peatland conservation represents a case in point: local community livelihoods have only recently come into focus, particularly within academic literature. Instead, many previous studies emphasise the need to conserve intact peat swamp forests for their carbon storage, as a habitat for flagship species such as the orangutan, and to provide fire-free landscapes. Here, we explore the socio-environmental issues being faced in the peatland landscapes of Central Kalimantan, Indonesia. This includes the loss of peat-swamp forest, decreases in peatland fish populations and related socio-cultural challenges such as potential loss of fishing livelihoods along with historic and continued experiences of marginalisation of indigenous communities. To find solutions to these complex and interrelated problems, an interdisciplinary approach which focuses on interdependencies and includes multiple worldviews is required. We propose an approach which deploys both Ethan Miller's use of livelihoods (incl. Miller, 2019) and biocultural approaches to conservation to analyse human-nonhuman relationships, with a focus on fish and fishing livelihoods. We draw on data from in-depth social and ecological research in two village communities in Central Kalimantan, and in so doing illustrate how fish conservation has the potential to support important biocultural and livelihood relationships between human and nonhuman communities in peatland areas. Our findings lend support to previous calls for biocultural approaches to conservation in other socio-ecological contexts, and lead us to conclude that tropical peatland conservation initiatives that integrate such approaches will result in improved outcomes for peatlands, forests, biodiversity and people. These findings will be relevant to other tropical peatland areas with high dependence on fishing as a source of livelihood, such as the peatlands of the Amazon and Congo basins.
As the COVID‐19 pandemic continues to affect societies across the world, the ongoing economic and... more As the COVID‐19 pandemic continues to affect societies across the world, the ongoing economic and social disruptions are likely to present fundamental challenges for current and future biodiversity conservation. We review the literature for outcomes of past major societal, political, economic and zoonotic perturbations on biodiversity conservation, and demonstrate the complex implications of perturbation events upon conservation efforts. Building on the review findings, we use six in‐depth case studies and the emerging literature to identify positive and negative outcomes of the COVID‐19 pandemic, known and anticipated, for biodiversity conservation efforts around the world. A number of similarities exist between the current pandemic and past perturbations, with experiences highlighting that the pandemic‐induced declines in conservation revenue and capacity, livelihood and trade disruptions are likely to have long‐lasting and negative implications for biodiversity and conservation e...
Peatlands are highly dynamic systems, able to accumulate carbon over millennia under natural cond... more Peatlands are highly dynamic systems, able to accumulate carbon over millennia under natural conditions, but susceptible to rapid subsidence and carbon loss when drained. Short-term, seasonal and long-term peat surface elevation changes are closely linked to key peatland attributes such as water table depth (WTD) and carbon balance, and may be measured remotely using satellite radar and LiDAR methods. However, field measurements of peat elevation change are spatially and temporally sparse, reliant on low-resolution manual subsidence pole measurements, or expensive sensor systems. Here we describe a novel, simple and low-cost image-based method for measuring peat surface motion and WTD using commercially available time-lapse cameras and image processing methods. Based on almost two years’ deployment of peat cameras across contrasting forested, burned, agricultural and oil palm plantation sites in Central Kalimantan, Indonesia, we show that the method can capture extremely high resolu...
The COVID-19 pandemic has caused global disruption, with the emergence of this and other pandemic... more The COVID-19 pandemic has caused global disruption, with the emergence of this and other pandemics having been linked to habitat encroachment and/or wildlife exploitation. High impacts of COVID-19 are apparent in some countries with large tropical peatland areas, some of which are relatively poorly resourced to tackle disease pandemics. Despite this, no previous investigation has considered tropical peatlands in the context of emerging infectious diseases (EIDs). Here, we review: (i) the potential for future EIDs arising from tropical peatlands; (ii) potential threats to tropical peatland conservation and local communities from COVID-19; and (iii) potential steps to help mitigate these risks. We find that high biodiversity in tropical peat-swamp forests, including presence of many potential vertebrate and invertebrate vectors, combined, in places, with high levels of habitat disruption and wildlife harvesting represent suitable conditions for potential zoonotic EID (re-)emergence. A...
Tropical forests and peatlands provide important ecological, climate and socio‐economic benefits ... more Tropical forests and peatlands provide important ecological, climate and socio‐economic benefits from the local to the global scale. However, these ecosystems and their associated benefits are threatened by anthropogenic activities, including agricultural conversion, timber harvesting, peatland drainage and associated fire. Here, we identify key challenges, and provide potential solutions and future directions to meet forest and peatland conservation and restoration goals in Indonesia, with a particular focus on Kalimantan. Through a round‐table, dual‐language workshop discussion and literature evaluation, we recognized 59 political, economic, legal, social, logistical and research challenges, for which five key underlying factors were identified. These challenges relate to the 3Rs adopted by the Indonesian Peatland Restoration Agency (Rewetting, Revegetation and Revitalization), plus a fourth R that we suggest is essential to incorporate into (peatland) conservation planning: Reduc...
Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major... more Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major contributor to carbon emissions globally. Being subterranean, these fires can be difficult to detect and track, especially during periods of thick haze and in areas with limited accessibility. Thermal infrared detectors mounted on drones present a potential solution to detecting and managing underground fires, as they allow large areas to be surveyed quickly from above and can detect the heat transferred to the surface above a fire. We present a pilot study in which we show that underground peat fires can indeed be detected in this way. We also show that a simple temperature thresholding algorithm can be used to automatically detect them. We investigate how different thermal cameras and drone flying strategies may be used to reliably detect underground fires and survey fire-prone areas. We conclude that thermal equipped drones are potentially a very powerful tool for surveying for fires...
The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought... more 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…
Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian populati... more Bottom-up regulatory factors have been proposed to exert a strong influence on mammalian population density. Studies relating habitat quality to population density have typically made comparisons among distant species or communities without considering variation in food quality among localities. We compared dietary nutritional quality of two Bornean orangutan populations with differing population densities in peatland habitats, Tuanan and Sabangau, separated by 63 km. We hypothesized that because Tuanan is alluvial, the plant species included in the orangutan diet would be of higher nutritional quality compared to Sabangau, resulting in higher daily caloric intake in Tuanan. We also predicted that forest productivity would be greater in Tuanan compared to Sabangau. In support of these hypotheses, the overall quality of the diet and the quality of matched dietary items were higher in Tuanan, resulting in higher daily caloric intake compared to Sabangau. These differences in dietary nutritional quality may provide insights into why orangutan population density is almost two times greater in Tuanan compared to Sabangau, in agreement with a potentially important influence of diet quality on primate population density.
The timing and frequency of flowering and fruiting events are key tropical forest characteristics... more The timing and frequency of flowering and fruiting events are key tropical forest characteristics that have substantial influence on fauna. Although our understanding of geographic variation in habitat‐wide timing and frequency of flowering and fruiting is advancing, corresponding information for individual tree species is limited. Thus, we compared climate and reproductive phenology of 16 tree species over 70 mo at two Bornean tropical peat‐swamp forest sites. We found significant inter‐site correlations in rainfall and temperature, and only small absolute temperature differences. In both sites, most species exhibited within‐site synchrony in flowering and fruiting onset. Broad‐scale flowering and fruiting onset frequency classifications showed high congruence between sites. Significant correlations in flowering and fruiting onset timing between sites were found for only 19 and 17 percent of the species, respectively. This remained the case when applying 1‐ and 2‐month lag periods ...
Key to the subfamilies of ants This key is a simplified version of Bolton (1994), filtered only t... more Key to the subfamilies of ants This key is a simplified version of Bolton (1994), filtered only to include subfamilies that have been recorded in the Southeast-Asian region. Subfamilies marked with * have been recorded in the Sabangau or Kalampangan forests.
The orangutan is the world's largest arboreal mammal, and images of the red ape moving throug... more The orangutan is the world's largest arboreal mammal, and images of the red ape moving through the tropical forest canopy symbolise its typical arboreal behaviour. Records of terrestrial behaviour are scarce and often associated with habitat disturbance. We conducted a large-scale species-level analysis of ground-based camera-trapping data to evaluate the extent to which Bornean orangutans Pongo pygmaeus come down from the trees to travel terrestrially, and whether they are indeed forced to the ground primarily by anthropogenic forest disturbances. Although the degree of forest disturbance and canopy gap size influenced terrestriality, orangutans were recorded on the ground as frequently in heavily degraded habitats as in primary forests. Furthermore, all age-sex classes were recorded on the ground (flanged males more often). This suggests that terrestrial locomotion is part of the Bornean orangutan's natural behavioural repertoire to a much greater extent than previously th...
Pteropus vampyrus natunae, the Bornean subspecies of the large flying fox, has important roles in... more Pteropus vampyrus natunae, the Bornean subspecies of the large flying fox, has important roles in pollination but unsustainable hunting has been reported in Malaysian states. We provide the first description of hunting techniques and intensity in Indonesian Borneo. In forests around Palangka Raya this species is captured in canopy-level nets to support trade in the provincial capital. We estimate that in 2003 4,500 individuals were extracted from a single location in 30 days, which, together with trends reported in interviews with hunters and traders, suggests that hunting in this region is intensive and probably causing severe population declines. Further surveys are needed throughout Kalimantan to determine if this trend is occurring around other cities and whether intervention is needed to safeguard viable populations.
Orang-utans (Pongo spp.) are primarily frugivorous (Morrogh-Bernard et al. 2009) and are often re... more Orang-utans (Pongo spp.) are primarily frugivorous (Morrogh-Bernard et al. 2009) and are often regarded as important seed dispersers (Corlett 1998). In Tanjung Puting, Borneo, Galdikas (1982) found intact seeds in 94% of faecal samples, with a median 111 seeds per defecation; and in Ketambe, Sumatra, Rijksen (1978) found seeds in 44% of faecal samples. Furthermore, orang-utans have large day ranges (e.g. mean = 968 m, range = 280–2834 m across adults in Sabangau; Harrison 2009) and slow passage rates of digesta through the gut (Caton et al. 1999), and, hence, may disperse seeds far from parent trees. Many seeds are also spat out or discarded at distances up to 75 m from parent trees (Galdikas 1982).
Here, we show how the mechanical properties of a thick-shelled tropical seed are adapted to permi... more Here, we show how the mechanical properties of a thick-shelled tropical seed are adapted to permit them to germinate while preventing their predation. The seed has evolved a complex heterogeneous microstructure resulting in hardness, stiffness and fracture toughness values that place the structure at the intersection of these competing selective constraints. Analyses of different damage mechanisms inflicted by beetles, squirrels and orangutans illustrate that cellular shapes and orientations ensure damage resistance to predation forces imposed across a broad range of length scales. This resistance is shown to be around the upper limit that allows cracking the shell via internal turgor pressure (i.e. germination). Thus, the seed appears to strike an exquisitely delicate adaptive balance between multiple selection pressures.
1. Interactions between conservation and the social sciences are frequently characterized by eith... more 1. Interactions between conservation and the social sciences are frequently characterized by either critique (of conservation by social scientists) or co-optation (of social scientific methods and insights by conservationists). 2. This article seeks to push beyond these two dominant positions by exploring how conservationists and social scientists can engage in mutually transformative dialogue. Jointly authored by conservation scientists and social scientists, it uses the global nexus of orangutan conservation as a lens onto current challenges and possibilities facing the conservation-social science relationship. 3. We begin with a cross-disciplinary overview of recent developments in orangu-tan conservation-particularly those concerned with its social, political and other human dimensions. 4. The article then undertakes a synthetic analysis of key challenges in orangutan conservation-working across difference, juggling scales and contexts and dealing with politics and political economy-and links them to analogous concerns in the conservation-social science relationship. 5. Finally, we identify some ways by which orangutan conservation specifically, and the conservation-social science relationship more generally, can move forward: through careful use of proxies as bridging devices, through the creation of new, shared spaces, and through a willingness to destabilize and overhaul status quos. This demands an open-ended, unavoidably political commitment to critical reflexiv-ity and self-transformation on the part of both conservationists and social scientists.
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