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The recently described peatlands of northern Peruvian Amazonia are relatively intact compared with peatlands elsewhere in the tropics. They make an important contribution to regional biodiversity and, by sequestering carbon, to climate change mitigation. Research to date has focused on their physical and biological aspects, but peatlands are not simply natural phenomena: they are used, valued and understood socially and culturally in profoundly different ways by different groups of people.This research project used an interdisciplinary participatory approach, working with peatland communities and stakeholders in Peru, to bring together the different perspectives needed to produce a comprehensive understanding which the natural sciences cannot achieve alone. The three central aims of the project were to 1) characterise the ecology and sociocultural values of the ecosystem types identified by local communities; 2) identify the strategies and challenges around community management of natural resources; and 3) identify opportunities for peatland conservation and maintenance of livelihoods. We worked with five peatland forest communities, three mestizo and two indigenous, in the Pastaza-Marañón Basin, which is the largest peat-forming area in lowland Peru. To address our aims we used a range of methods, both ecological (plot-based vegetation survey, measuring peat properties) and sociological (participatory mapping, interviews, focus groups).A key outcome of this work is a better understanding of the multifaceted importance of peatlands to local communities. The resources and spaces provided by peatland ecosystems were important culturally and socioeconomically to all five communities, but with pronounced differences relating to the communities’ different sociocultural and economic experiences and contexts. Another striking finding was that the nature of communities’ relationships with external actors, and their exposure to different opportunities and challenges, varied very markedly from one community to the next. For example, our study communities have experienced different interventions, some more successful and enduring than others, by government agencies and NGOs focusing mainly on biodiversity conservation; the success or otherwise of these past projects is likely to shape the willingness of communities to engage with future conservation efforts. Some communities have been more heavily influenced than others by the expansion of regional markets and value chains for timber and non-timber forest products into remote peatland areas over recent decades; other communities have been profoundly affected by activities of multinational extractive industries, including the oil industry and plantation agriculture.We conclude that future peatland conservation efforts and sustainable development projects in Peruvian Amazonia will need to recognize the significant variations from one community to the next in terms of the ways in which they use and value the peatlands, and in terms of their wider socio-economic and cultural contexts. Long-term protection of the peatlands will only be possible by engaging with communities individually, taking into account the concerns, needs, desires, threats, and opportunities particular to each one.

Funding: This work was supported by the Natural Environment Research Council (Grant No. NE/R016860/1 and NE/R000751/1), the German Research Foundation (BE 2116/32-1) for funding KAH; the Newton-Paulet Institutional Links Grant (Grant ref. 220–2018) for part-funding KHR and LESC, and to the Leverhulme Trust for part-funding LESC (Research Grant RPG-2018-306). Tropical peatlands are a globally important carbon store. They host significant biodiversity and provide a range of other important ecosystem services, including food and medicines for local communities. Tropical peatlands are increasingly modified by humans in the rapid and transformative way typical of the “Anthropocene,” with the most significant human—driven changes to date occurring in Southeast Asia. This review synthesizes the dominant changes observed in human interactions with tropical peatlands in the last 200 years, focusing on the tropical lowland peatlands of Southeast Asia. We identify the beginning of transformative anthropogenic processes in these carbon-rich ecosystems, chart the intensification of these processes in the 20th and early 21st centuries, and assess their impacts on key ecosystem services in the present. Where data exist, we compare the tropical peatlands of Central Africa and Amazonia, which have experienced very different scales of disturbance in the recent past. We explore their global importance and how environmental pressures may affect them in the future. Finally, looking to the future, we identify ongoing efforts in peatland conservation, management, restoration, and socio-economic development, as well as areas of fruitful research toward sustainability of tropical peatlands. Publisher PDF

This work was funded by the Wildlife Conservation Society, Gordon and Betty Moore Foundation (Grant #5439, MonANPeru network), NERC (Grant ref. NE/R000751/1), Concytec/British Council/Embajada Británica Lima/Newton Fund (Grant ref. 220-2018), Concytec/NERC/Embajada Británica Lima/Newton Fund (Grant ref. 001-2019), Leverhulme Trust (Grant ref. RPG-2018-306), Scottish Funding Council, and USAID/SWAMP program. Peatland pole forest is the most carbon-dense ecosystem in Amazonia, but its spatial distribution and species composition are poorly known. To address this knowledge gap, we quantified variation in the floristic composition, peat thickness, and the amount of carbon stored above and below ground of 102 forest plots and 53 transects in northern Peruvian Amazonia. This large dataset includes 571 ground reference points of peat thickness measurements across six ecosystem types. These field data were also used to generate a new land-cover classification based on multiple satellite products using a random forest classification. Peatland pole forests are floristically distinctive and dominated by thin-stemmed woody species such as Pachira nitida (Malvaceae), Platycarpum loretense (Rubiaceae), and Hevea guianensis (Euphorbiaceae). In contrast, palm swamps and open peatlands are dominated by Mauritia flexuosa (Arecaceae). Peatland pole forests have high peat thickness (274 ± 22 cm, mean ± 95% CI, n = 184) similar to open peatlands (282 ± 46 cm, n = 46), but greater than palm swamps (161 ± 17 cm, n = 220) and seasonally-flooded forest, terra firme, and white-sand forest where peat is rare or absent. As a result, peatland pole forest has exceptional carbon density (1,133 ± 93 Mg C ha−1). The new sites expand the known distribution of peatland pole forest by 61% within the Pastaza-Marañón Foreland basin, mainly alongside the Tigre river, to cover a total of 7540 km2 in northern Peruvian Amazonia. However, only 15% of the pole forest area is within a protected area, whilst an additional 26% lies within indigenous territories. The current low levels of protection and forest degradation but high threat from road paving projects makes the Tigre river basin a priority for conservation. The long-term conservation of peatland pole forests has the potential to make a large contribution towards international commitments to mitigate climate change. Publisher PDF

The effective conservation and sustainable management of tropical peatlands in Southeast Asia is a major challenge. Pervasive deforestation, drainage and conversion to agricultural land, is disrupting these ecosystems’ ability to sequester atmospheric carbon. Conserving peatlands in an intact state has been described as a “low hanging fruit in tackling climate change” by the international conservation community. Yet, peatland drainage and land conversion continue unabated. Focusing on Malaysia’s coastal peatlands, this study interrogates local and global perspectives on peatland conversion. We combine diverse datasets obtained using palaeoecological and social science research methods to provide a comprehensive context to this conservation challenge. We also identify where the local and global perspectives are in conflict and where they align. To do this, we employ a literature review and qualitative analysis of the interview data, enabling us to draw out key themes of local versus global discourses on the current management and future prospects of these peatland ecosystems. Palaeoecological data, derived from cores collected from three peatlands in Sarawak, Malaysian Borneo, provide a quantitative assessment of long-term ecological changes in these environments; qualitative surveys of local stakeholders provide complementary detail on the history of and future perspectives on human-peatland interaction. Finally, a comparison of interview data with key themes in the international discourses on peatland conservation, illustrates conflicts between the two. The coastal peatlands of Sarawak serve as a case study to explore the fragile context of sustainable tropical peatland management, illustrating the diversity of datasets and knowledges that can be integrated. This approach enables a more effective dialogue amongst the multiple stakeholders involved in the management of these globally important ecosystems.

Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models. The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland-carbon-climate nexus.

Conservation planning tends to focus on protecting species' ranges or landscape connectivity but seldom both-particularly in the case of diverse taxonomic assemblages and multiple planning goals. Therefore, information on potential trade-offs between maintaining landscape connectivity and achieving other conservation objectives is lacking. We developed an optimization approach to prioritize the maximal protection of species' ranges, ecosystem types, and forest carbon stocks, while also including habitat connectivity for range-shifting species and dispersal corridors to link protected area. We applied our approach to Sabah, Malaysia, where the state government mandated an increase in protected-area coverage of approximately 305,000 ha but did not specify where new protected areas should be. Compared with a conservation planning approach that did not incorporate the 2 connectivity features, our approach increased the protection of dispersal corridors and elevational connectivity by 13% and 21%, respectively. Coverage of vertebrate and plant species' ranges and forest types were the same whether connectivity was included or excluded. Our approach protected 2% less forest carbon and 3% less butterfly range than when connectivity features were not included. Hence, the inclusion of connectivity into conservation planning can generate large increases in the protection of landscape connectivity with minimal loss of representation of other conservation targets.Incorporación de la Conectividad a la Planeación de la Conservación para la Representación Óptima de Especies Múltiples y Servicios Ambientales Resumen Las tendencias de planeación de la conservación tienden a enfocarse en la protección de la distribución geográfica de las especies o en la conectividad de paisajes, pero rara vez se enfocan en ambas - particularmente para el caso de los ensamblajes taxonómicos y las metas múltiples de planeación. Por lo tanto, hay carencias en la información sobre las compensaciones potenciales entre mantener la conectividad de los paisajes y alcanzar otros objetivos de conservación. Desarrollamos una estrategia de optimización para priorizar la protección máxima de la distribución de las especies, los tipos de ecosistemas y los stocks de carbono de los bosques, a la vez que incluimos la conectividad del hábitat para las especies que modifican su distribución y los corredores de dispersión para conectar el área protegida. Aplicamos nuestra estrategia en Sabah, Malasia, en donde el gobierno estatal ordenó un incremento de ∼305, 000 ha en la cobertura de áreas protegidas sin especificar la ubicación de las nuevas áreas protegidas. En comparación con una estrategia de planeación de la conservación que no incorporó las dos características de la conectividad, nuestra estrategia incrementó la protección de los corredores de dispersión y la conectividad altitudinal en un 13% y 21% respectivamente. La cobertura de la distribución de las especies de plantas y vertebrados y de los tipos de bosque fue la misma con o sin la inclusión de la conectividad. Nuestra estrategia protegió 2% menos del carbono forestal y 3% menos de la distribución de mariposas que cuando no se incluyeron las características de conectividad en la estrategia. Por lo tanto, incluir a la conectividad en la planeación de la conservación puede generar grandes incrementos en la protección de la conectividad del paisaje con una pérdida mínima de representación para los demás objetivos de conservación.

The status of tropical peatlands, one of Earth’s most efficient natural carbon stores, is of increasing international concern as they experience rising threat from deforestation and drainage. Peatlands form over thousands of years, where waterlogged conditions result in accumulation of organic matter. Vast areas of Southeast Asian peatlands have been impacted by land use change and fires, whilst lowland tropical peatlands of Central Africa and South America remain largely hydrologically intact. To predict accurately how these peatlands may respond to potential future disturbances, an understanding of their long-term history is necessary. This paper reviews the palaeoecological literature on tropical peatlands of Southeast Asia, Central Africa and South America. It addresses the following questions: (i) what were the past ecological dynamics of peatlands before human activity?; (ii) how did they respond to anthropogenic and natural disturbances through the palaeoanthropocene, the period from whence evidence for human presence first appeared?; and, (iii) given their past ecological resilience and current exposure to accelerating human impacts, how might the peatlands respond to drivers of change prevalent in the anthropocene? Throughy synthesising palaeoecological records, this review demonstrates how tropical peatland ecosystems have responded dynamically, persisting through fire (both natural and anthropogenic), climatic and human-induced disturbances in the palaeoanthropocene. Ecosystem resilience does, however, appear to be compromised in the past c. 200 years in Southeast Asian peatlands, faced with transformative anthropogenic impacts. In combination, this review’s findings present a pantropical perspective on peatland ecosystem dynamics, providing useful insights for informing conservation and more responsible management. Natural Environment Research Council (NERC): NE/R016860/1 and NE/R000751/1.

This paper stemmed from discussions at a workshop held in Cornwall, UK, for which we thank the Biotechnology and Biosciences Research Council (BBSRC) through a GCRF‐IAA grant to the University of Exeter, and Borneo Nature Foundation (BNF) for funding. M.E.H.'s drafting of this paper was supported financially by BNF and A.H.'s research was funded through a doctoral scholarship by DAAD (German Academic Exchange Service). 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: Reducing Fires.Our analysis suggests that (a) all challenges have potential for impact on activities under all 4Rs, and many are inter‐dependent and mutually reinforcing, implying that narrowly focused solutions are likely to carry a higher risk of failure; (b) addressing challenges relating to Rewetting and Reducing Fire is critical for achieving goals in all 4Rs, as is considering the local socio‐political situation and acquiring local government and community support; and (c) the suite of challenges faced, and thus conservation interventions required to address these, will be unique to each project, depending on its goals and prevailing local environmental, social and political conditions.With this in mind, we propose an eight‐step adaptive management framework, which could support projects in both Indonesia and other tropical areas to identify and overcome their specific conservation and restoration challenges. Publisher PDF

This research was fully supported by a NERC Ph.D. Grant, from 2008 to 2012. The open access publication fees will be paid for by the University of St Andrews. Tropical peat swamp forests are invaluable for their role in storing atmospheric carbon, notably in their unique below-ground reservoirs. Differing from terra firme forests, the peat-forming function of tropical swamps relies on the integrity of discrete hydrological units, in turn intricately linked to the above-ground woody and herbaceous vegetation. Contemporary changes at a local, e.g. fire, to global level, e.g. climatic change, are impacting in the integrity and functioning of these ecosystems. In order to determine to what extent and predict their likely future response, it is essential to understand past ecosystem disturbance and resilience. Here, we explore the impact of burning on tropical peat swamp forests. Fires within degraded tropical peatlands are now commonplace; whilst fires within intact peat swamp forests are thought to be rare events. Yet little is known about their long-term natural fire regime. Using fossil pollen and charcoal data from three peat cores collected from Sarawak, Malaysian Borneo, we looked at the incidence and impact of local and regional fire on coastal peat swamp forests over the last 7000 years. Palaeoecological results demonstrate that burning has occurred in these wetland ecosystems throughout their history, with peaks corresponding to periods of strengthened ENSO. However, prior to the Colonial era c. 1839 when human presence in the coastal swamp forests was relatively minimal, neither local nor regional burning significantly impacted on the forest vegetation. After the mid-19th Century, at the onset of intensified land-use change, fire incidence elevated significantly within the peatlands. Although fire does not correlate with past vegetation changes, the long-term data reveal that open vegetation, a proxy for human forest clearance, does follow a similar pattern. Our results suggest that human activity may be strongly influencing and acting synergistically with fire in the recent past, leading to the enhanced degradation of these peatland ecosystems. However, intact tropical peat swamp forests can and did recover from local fire events. These findings support present-day concerns about the increase in fire incidence and combined impacts of fire, human disturbance and El Niño on peat swamp forests, with serious implications for biodiversity, human health and global climate change. Publisher PDF

In the version of this Analysis originally published, the following affiliation for A. Lohila was missing: ‘Finnish Meteorological Institute, Climate System Research, Helsinki, Finland’. This affiliation has now been added, and subsequent affiliations renumbered accordingly, in the online versions of the Analysis.

Summary 1.The coastal peat swamp forests of Sarawak, Malaysian Borneo, are undergoing rapid conversion, predominantly into oil palm plantations. This wetland ecosystem is assumed to have experienced insignificant disturbance in the past, persisting under a single ecologically-stable regime. However, there is limited knowledge of the past disturbance regime, long-term functioning and fundamentally the resilience of this ecosystem to changing natural and anthropogenic perturbations through time. 2. In this study, long-term ecological data sets from three degraded peatlands in Sarawak were collected to shed light on peat swamp forest dynamics. Fossil pollen and charcoal were counted in each sedimentary sequence to reconstruct vegetation and investigate responses to past environmental disturbance, both natural and anthropogenic. 3. Results demonstrate that peat swamp forest taxa have dominated these vegetation profiles throughout the last c. 2000-year period despite the presence of various drivers of disturbance. Evidence for episodes of climatic variability, predominantly linked to ENSO events, and wildfires is present throughout. However, in the last c. 500 years, burning and indicators of human disturbance have elevated beyond past levels at these sites, concurrent with a reduction in peat swamp forest pollen. 4. Two key insights have been gained through this palaeoecological analysis: (i) peat swamp forest vegetation has demonstrated resilience to disturbance caused by burning and climatic variability in Sarawak in the late Holocene, however (ii) coincident with increased fire combined with human impact c. 500 years ago, these communities started to decline. 5. Synthesis. Sarawak's coastal peat swamps have demonstrated resilience to past natural disturbances, with forest vegetation persisting through episodes of fire and climatic variability. However, palaeoecological data presented here suggest that recent, anthropogenic disturbances are of a greater magnitude, causing the observed decline in the peat swamp forest communities in the last c. 500 years and challenging the ecosystem's persistence. This study greatly extends our knowledge of the ecological functioning of these understudied ecosystems, providing baseline information on the past vegetation and its response to disturbance. This understanding is central to developing management strategies that foster resilience in the remaining peat swamp forests and ensure continued provision of services, namely carbon storage, from this globally important ecosystem.

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.

Science fields, including tropical peatland research, are facing persistent under-representation of women. In this perspective piece, we explore, as women at different stages of our career, our personal experiences of ‘what is it like to be a woman working in tropical peatland science’? We collected our responses and analysed them thematically. Although we come from a variety of different backgrounds and cultures, our responses all dealt with common issues, such as from practical challenges of being women in the field, persistent sexism, issues of harassment to navigating the politics of research as a woman. The peat swamp is seen as a site of rebellion against traditional gender roles. Senior female role models were also vital for us all, which highlights that mentoring schemes in aquatic and wetland research, as in other science fields, need further consideration and investment. Continuing to improve gender balance is central to effecting a positive change in research culture, and we stress that the issue of the ‘bravado’ surrounding fieldwork needs to be further explored and challenged. By pushing these ‘limits’ both in the field and in the academy, we will not only produce a more equal and compassionate working environment, but also ultimately improve our science.

A recent metabolic scaling theory predicts that plants minimize resistance to hydraulic conduction in the bulk transport network by narrowing the diameter of xylem conduits distally. We hypothesized that trees growing at high altitude or on nutrient-depleted soils would prioritize survival over minimizing hydraulic resistance, and that their vascular systems would be structured differently from those of trees growing under more benign conditions. In fact, conduits were observed to narrow towards the periphery of vascular system within all 45 trees of three species we investigated, and scaling relationships were indistinguishable across a range of environments. Thus, conduit tapering relationships appear to be invariant with respect to environmental conditions.

The time taken for forested tropical ecosystems to re-establish post-disturbance is of widespread interest. Yet to date there has been no comparative study across tropical biomes to determine rates of forest re-growth, and how they vary through space and time. Here we present results from a meta-analysis of palaeoecological records that use fossil pollen as a proxy for vegetation change over the past 20,000 years. A total of 283 forest disturbance and recovery events, reported in 71 studies, are identified across four tropical regions. Results indicate that forests in Central America and Africa generally recover faster from past disturbances than those in South America and Asia, as do forests exposed to natural large infrequent disturbances compared with post-climatic and human impacts. Results also demonstrate that increasing frequency of disturbance events at a site through time elevates recovery rates, indicating a degree of resilience in forests exposed to recurrent past disturbance., Forest recovery after past disturbances can help to understand how forests will respond to future scenarios. Here, the authors analyse palaeoecological records from tropical forests and find that Central American and African forests have recovered faster after disturbances than those in South America and Asia.