Indonesian Borneo Research Articles

Education4Conservation, an evolving international program and 14-year curriculum of environmental education.

Education4Conservation evolved from an environmental education program in Balikpapan Bay, Indonesian Borneo, after its critical evaluation. The initial goal of the program was to support the development of future conservation leaders who would join the ongoing efforts to conserve proboscis monkeys (Nasalis larvatus) and their coastal forest habitat in Balikpapan Bay. We realized that to achieve this goal, we would need to work with students from the age of 4 years and continue to educate them for many years. We also realized that we needed to focus more on mentoring teachers and incorporating their feedback into the curriculum. The new program, which is in line with the new Indonesian national curriculum (Kurikulum Merdeka), has proved attractive to teachers and has spread from Kalimantan to other Indonesian islands and countries outside Asia. The curriculum continues to improve through regular monthly revisions that incorporate feedback from teachers, while teachers' pedagogical skills have improved through guidance provided by responses to each of their reports. We have been following and supervising participants since the Education4Conservation program began in 2022. Although a preliminary evaluation seems to indicate substantial improvements over the earlier program (in terms of high participation, positive teacher response, improved reporting skills, and increased clarity and applicability of the curriculum), it remains to be seen whether the program ultimately achieves its primary goal to help raise some of the students into conservation leaders.

Conservation among oil palm plantations? Mammalian diversity in protected forest areas of a mixed-use landscape in Indonesian Borneo

Conservation among oil palm plantations? Mammalian diversity in protected forest areas of a mixed-use landscape in Indonesian Borneo

Fire in the rainforest: A 3200‐year history of fire in a West Kalimantan, Indonesia, tropical rainforest

AbstractDespite its perceived historical rarity, fire is an important disturbance in tropical rainforests. Very large rainforest fires have been observed multiple times in recent decades, often during years of strong El Niño‐Southern Oscillation droughts. Fire in rainforest has major short‐term consequences for humans and wildlife by converting forest to fire‐prone fern, shrub, and grass, but the long‐term effects remain to be seen. Borneo's indigenous groups have been using fire to clear land for centuries, yet the prevalence and spatial patterns of premodern fire across forest types in Borneo are not well understood. This research set out to reconstruct fire in a 1500‐ha primary rainforest spanning 800 m of elevation in Indonesian Borneo with the goal of elucidating the role humans have played in rainforest fire. We found that humans played an important role in the occurrence of fire in recent centuries. Evidence of fire—charcoal >2 mm—is more abundant in forest types where humans would be more likely to live and/or practice swidden agriculture. However, pyrogenic material is ubiquitous across the study area, showing that all forest types have experienced fire. A set of 50 radiocarbon dates showed that in lowland areas—where human‐caused fire is most likely—fire occurred throughout the last 3200 years, peaking 1300–1600 ce. The upland areas lacked evidence of fire before 1250 ce but otherwise had a similar pattern to the lowlands. The period of high fire coincides with regional demographic changes as well as regional droughts documented elsewhere in Southeast Asia. In upland areas, fires likely burned only under regional drought when fires could more easily spread upslope. Although forest plot studies at this site show little structural evidence of past fires, tree diversity is lower than expected in the most burned areas (alluvial benches). Thus, our results suggest that land clearance was a major source of fire, but the current intact state of these rainforests indicates that they were largely resilient to fires and land use hundreds of years ago. Recent fires mirror patterns of fire spread that occurred hundreds of years ago, though their severity and extent are likely much greater.

Distinct Island Lineages of Binturong (Arctictis binturong) from Indonesia and Its Conservation Implications

Binturong (Arctictis binturong) is a threatened carnivore that inhabits the forests of South and Southeast Asia. Despite its wide range, binturong is relatively scarce across its habitat distribution and is currently under the threat of poaching and illegal trade. Captive breeding has unfortunately been conducted rather haphazardly with a lack of origin record maintained, implicating potential risks to the management such as inbreeding or genetic swamping. This study thus aims to characterise the phylogenetic relationship of Indonesian binturong within the context of Southeast Asian binturong and further probe the distinctness of lineages originating from Java, Sumatra, Indonesian Borneo, and Bangka using Cytochrome B (CytB) and Cytochrome C Oxidase Subunit 1 (CO1). Genetic distance, phylogram topology, and haplotype analysis of both encoding genes further corroborate the distinctness of Java, Borneo, and Bangka binturong from other binturong from Indochinese regions such as India, Laos, and Myanmar. Search for prospective single nucleotide polymorphism markers to discriminate island lineages consistently found that each Java, Bangka, and Bornean binturong be distinct from each other and other lineages, especially when assessed using haplotype-based clustering. Assigning binturong originated from Sumatra is nonetheless more complicated, suggesting the possibility. Our findings substantiated the much-needed systematic research of Southeast Asian binturong as ex-situ insurance population management grows in Indonesia and other parts of the world to protect the diversity of binturong lineages and their corresponding unique evolutionary history.

Racial Fictions at Work in a Regional Plantation Complex

In this article, I argue for a local and regional focus on landscape racializations rather than a national lens for engaging with the Plantationocene. Racial formations on and around Indonesia’s plantations have emerged differently across regions and through varied colonial-era and contemporary land and labor politics. Inspired by diverse scholars’ historical and contemporary treatments of embodied and emplaced racialisms, I use a region in West Kalimantan Province (Indonesian Borneo) to argue that it is misleading to claim a national-level Plantationocene history relevant to all subnational regions. I then unpack racialized and gendered fictions deployed by state actors to justify the protracted political violence (1967–74) that led to the national state’s expropriation of land held by smallholders of Chinese and Chinese-Dayak descent in half the province. All seized land was reclassified as state land to mask its origins and redistributed to non-Chinese local people and transmigrants who worked the regional rubber plantation. This violent reracializing of the West Kalimantan landscape is the antithesis of the racialisms associated with plantation production in Java and Sumatra. Knowing this region-specific history can help in supporting contemporary struggles against entrenched patterns of racialized injustice.

Quantifying causal teleconnections to drought and fire risks in Indonesian Borneo

AbstractFires occurring over the peatlands in Indonesian Borneo accompanied by droughts have posed devastating impacts on human health, livelihoods, economy and the natural environment, and their prevention requires comprehensive understanding of climate‐associated risk. Although it is widely known that the droughts are associated with El Niño events, the onset process of El Niño and thus the drought precursors and their possible changes under the future climate are not clearly understood. Here, we use a causal network approach to quantify the strength of teleconnections to droughts at a seasonal timescale shown in observations and climate models. We portray two drivers of June‐July‐August (JJA) droughts identified through literature review and causal analysis, namely Niño 3.4 sea surface temperature (SST) in JJA (El Niño Southern Oscillation [abbreviated as ENSO]) and SST anomaly over the eastern North Pacific to the east of the Hawaiian Islands (abbreviated as Pacific SST) in March‐April‐May (MAM) period. We argue that the droughts are strongly linked to ENSO variability, with drier years corresponding to El Niño conditions. The droughts can be predicted with a lead time of 3 months based on their associations with Pacific SST, with higher SST preceding drier conditions. We find that under the SSP585 scenario, the Coupled Model Intercomparison Phase 6 (CMIP6) multi‐model ensembles show significant increase in both the maximum number of consecutive dry days in the Indonesian Borneo region in JJA (p = 0.006) and its linear association with Pacific SST in MAM (p = 0.001) from year 2061 to 2100 compared with the historical baseline. Some models are showing unrealistic amounts of JJA rainfall and underestimate drought risks in Indonesian Borneo and their teleconnections, owing to the underestimation of ENSO amplitude and overestimation of local convections. Our study strengthens the possibility of early warning triggers of fires and stresses the need for taking enhanced climate risk into consideration when formulating long‐term policies to eliminate fires.

Camptostemon philippinensis, a new record of endangered mangrove species in the Balikpapan Bay, East Kalimantan, Indonesia

Background Camptostemon philippinensis, found in mangrove forests in Indonesia and the Philippines, is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List. It is found primarily in isolated mangrove forests in Kalimantan (Indonesian Borneo) and Sulawesi in Indonesia. Despite significant studies on mangrove biodiversity in this region, the occurrence of C. philippinensis in Balikpapan Bay, East Kalimantan, is not extensively recorded. Methods The study was conducted by exploring the mangrove forests along Balikpapan Bay. The first survey of about 200 km was conducted to observe mangrove vegetation and found one C. philippinensis tree. The second survey focused on the area around the first discovered C. philippinensis tree to census and record its growth stage and distribution. Results The study recorded a population of 527 individuals of C. philippinensis in Pantai Lango Village, East Kalimantan, dominated by seedlings. The high number of seedlings indicates good natural regeneration potential, but the low number of trees indicates intense competition for space in a restricted habitat. This species inhabits a small and restricted area in Balikpapan Bay, in the middle area of Balikpapan Bay, and is associated with other mangrove flora, such as Rhizophora apiculata, Rhizophora mucronata, Sonneratia alba, Avicennia alba, Lumnitzera littorea, Osbornia octodonta, Ceriops tagal, and Xylocarpus granatum. Conclusions C. philippinensis is vulnerable to habitat damage from anthropogenic activities, which could lead to local extinction. Its natural habitat in Balikpapan Bay also has the potential to be under pressure due to the development of Indonesia’s new capital city (Ibu Kota Nusantara/IKN). It emphasizes the need to understand the ecological role of this protected flora in the natural habitat of protected fauna (the proboscis monkey). Documenting the population of C. philippinensis is crucial for conservation efforts, including propagation and understanding its ecological role.

Lepidothelphusa menneri n. sp. (Crustacea: Brachyura: Gecarcinucidae), first record of the genus from Kalimantan, Indonesia.

The gecarcinucid freshwater crab genus, Lepidothelphusa Colosi, 1920, is known only from Sarawak in northern Borneo, with six recognised species i.e. Lepidothelphusa cognettii (Nobili, 1903); L. flavochela Grinang & Ng, 2015; L. limau Grinang & Ng, 2015; L. loi Grinang & Ng, 2015; L. padawan Grinang & Ng, 2015; and L. sangon Grinang & Ng, 2015. The genus is now reported from Indonesian Borneo for the first time, from specimens recently collected from Gunung Kelam in Sintang Regency, Kalimantan Barat Province. Lepidothelphusa menneri n. sp. has a very distinctive tri-coloured pattern in life, unique among congeners. It can also easily be separated from congeners by carapace, epistome, male pleonal and male first gonopod characters.

Forest Law Harmony: Bridging the Gap between Forest Area Utilization Agreements (PPKH) and Land Ownership Certificates (Sertifikat Tanah) in Land Ownership with Penal Mediation Approaches

This article explores conflicts from overlapping forest lands allocated through Indonesia's Forest Area Utilization Agreements (PPKH) with occupied customary lands lacking legal ownership certificates. Companies and forest communities often clash over ancestral tenure rights. Mediation balances economic growth, social justice, and environmental sustainability. The paper examines efforts to bridge regulatory gaps between PPKH licensing and Land Ownership Certificates (Sertifikat Tanah) through penal mediation in Indonesian Borneo. Comparative case studies analyze mediation techniques, shaping legal certainty, sustainable land use, governance, and benefit-sharing outcomes. Mediated agreements resulted in formal permit adjustments and land titles for 20,000 hectares, providing legal security. Settlements enhanced social equity through shared employment, profits, and infrastructure. Success factors include participatory mapping, company financing for bureaucratic procedures, leveraging customary institutions, and embedding multi-stakeholder oversight. Partial shortcomings highlight the need for further policy and power structure reforms to fully realize mediation potential in balancing nationwide forest land conflicts.

A Morphological Perspective on Verb Formation: A Contrast Analysis Affixes of English, Indonesia and Banjar Kuala Language of South Borneo

The purpose of this research is to find similarities and differences, as well as to describe the types of prefixes and suffixes in English, Indonesian and Banjar in Indonesian Borneo, to develop a description of the socio-cultural background of speakers of Banjar Kuala language and describe the morphology and syntax of the Banjar Kuala language: Formation of verbs in Banjar Kuala Borneo/South Kalimantan. Describes verbs formed from affixes, namely prefixes and suffixes, infixes, and prefixes + suffixes like the prefix maN-/mam-/ ( /maNujun/ 'fishing', /mambanu/ 'selling water', and the prefix maN-/ma- and ending -an like, /unjun/ 'kail' becomes /maunjunan/ 'all for fish' and /mambanuan/ 'sell all the water' other prefixes and suffixes maN- and -i: /maunjuni/ 'fishing' in a certain place/.and other verbs like /manjukuni/ 'give a boat' and prefix maN - and suffix i- + suffix -will /maunjanikan/ 'fishing for', /manjukuniakan/ 'to run a boat for' This research project clearly illustrates the differences in verb formation between the Banjar-Kuala language in South Kalimantan, Indonesia and the international language, namely English .both can be seen from the use of affixes in the formation of verbs, the similarity of the two can form verbs with the addition of prefixes and suffixes, while the difference is that English cannot form verbs from infixes, but Banjar language can form verbs from the same infixes as Indonesian and other languages in the world.

Camptostemon philippinensis, a new record of endangered mangrove species in the Balikpapan Bay, East Kalimantan, Indonesia

Background Camptostemon philippinensis, found in mangrove forests in Indonesia and the Philippines, is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List. It is found primarily in isolated mangrove forests in Kalimantan (Indonesian Borneo) and Sulawesi in Indonesia. Despite significant studies on mangrove biodiversity in this region, the occurrence of C. philippinensis in Balikpapan Bay, East Kalimantan, is not extensively recorded. Methods The study was conducted by exploring the mangrove forests along Balikpapan Bay. The first survey of about 200 km was conducted to observe mangrove vegetation and found one C. philippinensis tree. The second survey focused on the area around the first discovered C. philippinensis tree to census and record its growth stage and distribution. Results The study recorded a population of 527 individuals of C. philippinensis in Pantai Lango Village, East Kalimantan, dominated by seedlings. The high number of seedlings indicates good natural regeneration potential, but the low number of trees indicates intense competition for space in a restricted habitat. This species inhabits a small and restricted area in Balikpapan Bay, in the middle area of Balikpapan Bay, and is associated with other mangrove flora, such as Rhizophora apiculata, Rhizophora mucronata, Sonneratia alba, Avicennia alba, Lumnitzera littorea, Osbornia octodonta, Ceriops tagal, and Xylocarpus granatum. Conclusions C. philippinensis is vulnerable to habitat damage from anthropogenic activities, which could lead to local extinction. Its natural habitat in Balikpapan Bay also has the potential to be under pressure due to the development of Indonesia’s new capital city (Ibu Kota Nusantara/IKN). It emphasizes the need to understand the ecological role of this protected flora in the natural habitat of protected fauna (the proboscis monkey). Documenting the population of C. philippinensis is crucial for conservation efforts, including propagation and understanding its ecological role.

Accounting for seedling performance from nursery to outplanting when reforesting degraded tropical peatlands

Reforestation is promoted to address the dual global climate and biodiversity crises. This is particularly relevant for carbon‐rich, biodiverse tropical peatlands, for which active reforestation typically involves two post‐germination stages: nursery rearing of seedlings, then outplanting. Yet, linkages between these stages and cumulative seedling performance are rarely quantified during tropical peatland reforestation. By monitoring tree seedling survival and growth, we investigate factors influencing seedling performance (species identity, seedling source, treatments, and climate), whether nursery performance predicts outplanting performance, and calculate cumulative survival (nursery plus outplanting) in Sebangau National Park, Indonesian Borneo. Standardized survival at 2 years was higher in the nursery (mean 67% across 40 species) than outplanting (44% across 24 species). For nursery and outplanting, species identity was the main source of variation in survival and height growth. Seedling source, treatments, site condition, and precipitation had no significant impact on survival but did influence growth in some cases. Nursery survival did not predict outplanting survival, but nursery height did predict outplanting height. Across species, around a quarter of seedlings survived from nursery to outplanting over 4 years. Cumulative survival represents a more realistic basis for assessing the genetic and other resource costs of tropical peatland reforestation. Our two‐phase approach identified outplanting as the greater bottleneck to cumulative seedling survivability. We argue that the nursery stage may be used to harden seedlings for degraded peatland conditions by selecting more relevant treatments (e.g. flooding) and screening for resilience to common disturbances (e.g. fire) to enhance outplanted, and thus cumulative, seedling survival.

Building capacity for estimating fire emissions from tropical peatlands; a worked example from Indonesia

Tropical peatlands are globally significant in the terrestrial carbon cycle as they are comprised of a large forest carbon sink and a large peat carbon store—both of which can potentially be exchanged with the atmosphere on decadal time frames. Greenhouse gas emissions from fire-disturbance and development of tropical peatlands over the last few decades, and the potential for ongoing emissions, highlights the need for policy to slow or halt emissions and to activate mechanisms to sequester carbon through restoration of degraded peatlands. The UN REDD + scheme provides a means for developing countries to receive payments for avoided deforestation and forest degradation, but the steps to achieve REDD+ compliance are rigorous and the details required can be a barrier to activating benefits—especially for peatlands where repeated cycles of fire interrupt forest recovery and create a range of recovery classes. Therefore, to improve estimates of peat fire emissions and of carbon balance of tropical peatlands, the biomass and combustion factor parameters need to be developed and applied according to forest recovery stage. In this study we use published activity data from the extensive 1997 fires in the peatlands of Indonesian Borneo to detail a transparent and accountable way to estimate and report emissions from tropical peatland fires. This example for estimating and reporting emissions is provided to assist REDD+ countries to efficiently develop their capacity for improving emissions estimates from fire-impacted tropical peatlands.

A new species of Trichoglottis (Orchidaceae) from eastern Kalimantan, Indonesia

Trichoglottis najibii Yudistira & Mustaqim is described here as a species new to science based on a specimencollected from eastern Kalimantan, Indonesian Borneo. The most unique characteristics of this species are thethe labellum’s lateral lobes adnate to the column and the 8–9 mm long cylindric and slightly curving spur. Adetailed description, distribution, habitat and ecology, notes, illustrations, and photographs are provided forthe new species.

Haunting the Factory: Indonesian Modernity and the Spiritual Landscape of Central Kalimantan

ABSTRACT This article explores enchantments accompanying industrial development and the national discourse of modernity in the ecologically fragile swamp landscape of Central Kalimantan, situated in the southern part of Indonesian Borneo. Focusing on the experiences of the Ngaju Dayak, a local indigenous group, and mass-mediated narratives on enchantments of (national) development, we explore the promises and anxieties of the modern industrial schemes that become part of their everyday lives. By bringing together the discussions of animate spiritual landscapes and Indonesian modernity, we explore the politics and capacity of the Dayak and the spirits to invite, deny or resist the effects of modern infrastructure projects. We examine the landscape of collaborations, dreams and anxieties influenced by capitalist industrial development (Ong 2010; Taussig 2010; Tsing 2005; Bubandt 2015; Duile 2020). We argue that a plurality of enchantments exists and local indigenous groups must navigate between these enchantments and national modernity projects.

Co-Creation in Community-based Storytelling

The emergence of immersive media and new technologies such as Augmented Reality (AR), Virtual Reality (VR) and Mixed Reality (MR) has contributed to the shift in interactive documentary and community-based storytelling practices. Under the umbrella term known as Extended Reality (XR), the new technologies intervene with and provide the author with a space to negotiate authorship of interactive documentaries in a co-creation setting with the Salako community in Malaysia. Malaysia is a country in the Southeast Asia region. It occupies the Malay Peninsula and part of the Island of Borneo. There are over 120 different communities in Malaysia, and Sarawak, the largest state, has the most diverse communities. The Salako community migrated from West Kalimantan Province of the Indonesian Borneo to Pueh, Sarawak, in the 1870s due to political and geographical reasons. Today, the Salako community members are still involved in farming, and they perform various rituals to seek blessings to avoid harm to their crops. This study investigates the Salako community's storytelling practices in Pueh, Sarawak. It focuses on the co-creation of an interactive documentary storytelling of the paddy farming rituals among the community. Furthermore, it also aims to understand the dynamic relationship negotiated by the author and the community members. Therefore, the questions guiding the study can be framed as follows: How can practice-based research be used in negotiating collaboration with the Salako community? What insights can the author learn from the Salako community that contributes to the creative research practice? The study considers the concept of rhizome, introduced by French philosophers Gilles Deleuze and Félix Guattari, as an approach to decolonising storytelling structure in the co-creation of community-based storytelling with the Salako community. The conceptual and theoretical framework bring together recent studies on community-based storytelling and empirical evidence on interactive documentaries and co-creation with a focus on community storytelling practices. The author engages practice-based research as the creative research practice in this study. In the interactive documentary titled Listening to the Salako: Voices of the Paddy and Human, the author will share the creative research process involved in the initial phase of the study. Highlighting the observations and perspectives drawn from the interactive documentary storytelling project with the Salako community, the article offers insights into understanding the nexus of care, collaboration and craft. In addition, it also looks at how practice-based research is used in community engagement and the negotiation of authorship through a participatory design process with the Salako community in Malaysia. In this study, the author argues that while practice-based research is central to navigating the layers of complexity in community engagement, the element of care, collaboration and craft present additional dimensions that can further unpack and contribute to the understanding of creative research practice. The article ends with a discussion of the impact and implications of practice-based research in empowering both the author and the Salako community in negotiating collaboration in the co-creation of the interactive documentary, Listening to the Salako: Voices of the Paddy and Human.

A 50 year decennial survey of male Bornean orangutans (Pongo pygmaeus wurmbii) with supplemental genetic analysis in Tanjung Puting National Park, Indonesia

Abstract. Galdikas BM, Linsky RE, Djojoasmoro R, Lorenz J, Wagner RS. 2023. A 50 year decennial survey of male Bornean orangutans (Pongo pygmaeus wurmbii) with supplemental genetic analysis in Tanjung Puting National Park, Indonesia. Biodiversitas 24: 2587-2595. This study investigates the declining presence of adult males in a protected wild population of Bornean orangutans (Pongo pygmaeus wurmbii) at the Camp Leakey study area in Tanjung Puting National Park (TPNP), Central Kalimantan, Indonesian Borneo. Orangutan populations are in decline due to habitat destruction and fragmentation. Documenting changes within existing orangutan populations over time is important to understand demographic changes that may indicate pre-extinction processes and imminent collapse. Wild orangutan behavior has been studied at Camp Leakey since 1971. Observations of orangutans over the past five decades have documented a greatly decreased number of encounters with flanged adult males. A supplementary six-month genetic study was hindered by the fact that only two adult males briefly appeared in the study area in 2016 as compared to 40 adult male encounters in the same time period in 1976. The decline which appears most visible in data from 1986 to 1996 continues into 2006 and 2016. Genotypes from 24 wild adult orangutans encountered in 2016 were analyzed to assess the expected genetic parameters of a wild orangutan population. Pairwise relatedness was high among and between adult females and subadult males. The only two flanged males present during the genetic survey shared zero pairwise relatednesses. However, both flanged males had non-zero pairwise relatedness with other members of the Camp Leakey community and thus it is likely they were from different local areas. These data show the genetic consequences of the observed demographic changes. As TPNP forests have become disconnected from neighboring habitats, natural orangutan male dispersal may be disrupted. Disruption of male dispersal would increase the risk of accelerated extirpation for the orangutan population in TPNP as well as other orangutan populations, especially those that are remnant and less protected.

Preserving of Hornbill Bird through 3-Dimensional Animation Clips

Post-Covid-19 pandemic conditions, the use of digital technology in animation and multimedia can produce works that can be used as a solution to existing problems, especially in the conservation of the Indonesian Borneo hornbill. The design in the form of a film or animation clip aims to educate the importance of hornbill conservation. The method used in this study uses a qualitative descriptive method with data collection and data processing, in the technical implementation of the animation pipeline, namely the stages of pre-production, pre-production, and post-production. The results of this study have succeeded in using these stages and producing a video or animation clip entitled The Spirit of Ampong with three-dimensional techniques. It is hoped that the results of the design will have a positive impact on the conservation of the hornbill.

Implications of large-scale infrastructure development for biodiversity in Indonesian Borneo

Indonesia is embarking on an ambitious relocation of its capital city to Kalimantan, Borneo, bringing with it major urban and road infrastructure. Yet, despite being one of the world's most biologically diverse regions, the potential implications of this development for wildlife have yet to be fully assessed. We explored the potential impacts of the capital relocation, and road expansion and upgrades to critical habitat for medium-large mammals (>1 kg) using camera trap data from 11 forested landscapes. We applied Bayesian multi-species occupancy models to predict community and species-level responses to anthropogenic and environmental factors. We extrapolated spatial patterns of occupancy and species diversity across the forests of Kalimantan and identified “critical habitats” as the top 20th percentile of occupancy and species richness values. We subsequently overlapped these critical habitat layers with infrastructure impact zones to estimate the area that could potentially be affected by direct or secondary impacts. At both the community and species-level, distance to primary roads had the strongest negative influence on habitat-use. Occupancy was also influenced by forest quality and multidimensional poverty conditions in adjacent villages, demonstrating the sensitivity of biodiversity to socio-ecological pressures. Less than 1 % of the critical habitat for the threatened mammal community lay within the direct impact zone (30 km radius) of the capital relocation. However, approximately 16 % was located within 200 km and could potentially be affected by uncontrolled secondary impacts such as urban sprawl and associated regional development. The often-overlooked secondary implications of upgrading existing roads could also intersect a large amount of critical habitat for lowland species. Mitigating far-reaching secondary impacts of infrastructure development should be fully incorporated into environmental impact assessments. This will provide Indonesia with an opportunity to set an example of sustainable infrastructure development in the tropics.

Oldest Basement (ca. 462 Ma) in Indonesian Borneo and its Implication for Early Paleozoic Tectonic Evolution of SE Asia

AbstractThe lack of preserved basement results in uncertain placements of many terranes in Southeast Asia. Here, we flag the first evidence of the oldest basement in Indonesian Borneo, which can help locate terranes in Borneo on the northern margin of Gondwana in the early Paleozoic and explain the regional tectonic setting of the island. Two schist samples from the Embuoi Complex in the Semitau Block, Northwest Kalimantan yielded zircon U‐Pb dates of 453.3 ± 1.9 Ma and 462.4 ± 2.6 Ma, respectively, representing the formation time of the protolith. Petrographic, internal structural and high Th/U ratios of zircons indicate that the protolith of schists is of magmatic origin. The zircons have εHf(t) values of –4.1 to +1.1 and Hf model ages of 1.37–1.69 Ga, indicating they were derived from a mixed source of juvenile crust with old components. By comparison of zircon age distribution, two‐stage Hf model ages and εHf(t) variations of the early Paleozoic igneous rocks from Semitau with those of South China, Tengchong–Baoshan, and Indochina, the Semitau Block was most likely a part of or placed next to the Indochina Block of northern Gondwana during the early Paleozoic. Such a similar tectono‐magmatic pattern on northern Gondwana formed a prolonged early Paleozoic arc‐related belt associated with subduction of the Proto‐Tethyan Ocean.