A new method for performing smouldering combustion field experiments in peatlands and rich-organic soils

Smouldering ground fires have severe environmental implications. Their main effects are the release of large amounts of carbon to the atmosphere with loses of organic soil and its biota. Quantitative data on the behaviour of smouldering wildfires are very scarce and are needed to understand its ecological effects, to validate fuel consumption and smouldering propagation models and to develop danger-rating systems. We present, for the first time, a methodology for conducting smouldering experiments in field conditions. This method provides key data to investigate smouldering combustion dynamics, acquire fire behaviour metrics and obtain indicators for ecological effects of smouldering fires. It is to be applied in all types of undisturbed soils. The experimental protocol is based on a non-electric ignition source and the monitoring system relies on combining both point and surface specific temperature measurements. The methodology has been developed and applied by means of large series of replicate experiments in highly organic soils at the forest–grassland treeline of the Peruvian Andes. The soil tested exhibited weak ignition conditions. However, transition to oxidation phase was observed, with smouldering combustion during 9¿h at 15-cm depth and residence times at temperatures above dehydration of ~22¿h.Peer ReviewedPreprin

¿Cómo avanzar en la conservación de los bosques de Polylepis y su diversidad biológica?

Polylepis is the dominant genus of the high Andean forest vegetation and they have a crucial ecological role. However, these forests are highly endangered and many of their biological aspects are still unknown. In this context, a series of questions were formulated with the aim that their resolution would contribute to a better understanding of Polylepis’dynamics and biological diversity, as well as improve their conservation efforts. Twenty one speakers from the V International Congress of Conservation and Ecology of Polylepis forests participated in the formulation of 67 questions related to these forests. Comments and additional information were received via email and google doc spreadsheet, open to the participants. Afterwards, two workshops were organized with the researchers to formulate, discuss, analyze and define the final list, narrowing down to a total of 40 questions. The questions were categorized into 6 different topics: Taxonomy, Ecology and Biogeography, Genetics, Conservation, Ethnobiology and Climate Change. We hope these questions will be considered as a priority for new research agendas and to define joint efforts for Polylepis forest conservation. El género Polylepis es dominante en los bosques a mayor elevación en los Andes y es de excepcional importancia ecológica. Sin embargo, estos bosques están gravemente amenazados y muchos aspectos de su biología permanecen poco conocidos. A razón de esto, identificamos preguntas que al ser resueltas contribuirán al mejor entendimiento de la dinámica de los bosques de Polylepis y con esto mejorar las acciones para su conservación y su diversidad biológica. Veintiún conferencistas que asistieron al V Congreso Internacional de Ecología y Conservación de los bosques de Polylepis participaron en la formulación de 67 preguntas asociadas a estos bosques. Los comentarios e insumos fueron recibidos mediante correo electrónico y a través de una matriz desarrollada en hojas de cálculo de google compartida con los participantes. Se realizaron dos talleres continuos con los investigadores, obteniendo una lista final de 40 preguntas formuladas, discutidas, analizadas y consensuadas. Las preguntas están divididas en 6 áreas temáticas: Taxonomía, Ecología y Biogeografía, Genética, Conservación, Etnobiología y Cambio Climático. Esperamos que estas preguntas sean consideradas como prioritarias para la agenda de investigación ya que pretenden generar un marco general para definir esfuerzos conjuntos para la conservación de los bosques de Polylepis

Assessing changes in global fire regimes

PAGES, Past Global Changes, is funded by the Swiss Academy of Sciences and the Chinese Academy of Sciences and supported in kind by the University of Bern, Switzerland. Financial support was provided by the U.S. National Science Foundation award numbers 1916565, EAR-2011439, and EAR-2012123. Additional support was provided by the Utah Department of Natural Resources Watershed Restoration Initiative. SSS was supported by Brigham Young University Graduate Studies. MS was supported by National Science Centre, Poland (grant no. 2018/31/B/ST10/02498 and 2021/41/B/ST10/00060). JCA was supported by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 101026211. PF contributed within the framework of the FCT-funded project no. UIDB/04033/2020. SGAF acknowledges support from Trond Mohn Stiftelse (TMS) and University of Bergen for the startup grant ‘TMS2022STG03’. JMP participation in this research was supported by the Forest Research Centre, a research unit funded by Fundação para a Ciência e a Tecnologia I.P. (FCT), Portugal (UIDB/00239/2020). A.-LD acknowledge PAGES, PICS CNRS 06484 project, CNRS-INSU, Région Nouvelle-Aquitaine, University of Bordeaux DRI and INQUA for workshop support.Background The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Results Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios. Conclusion The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.Peer reviewe

A new method for performing smouldering combustion field experiments in peatlands and rich-organic soils

Smouldering ground fires have severe environmental implications. Their main effects are the release of large amounts of carbon to the atmosphere with loses of organic soil and its biota. Quantitative data on the behaviour of smouldering wildfires are very scarce and are needed to understand its ecological effects, to validate fuel consumption and smouldering propagation models and to develop danger-rating systems. We present, for the first time, a methodology for conducting smouldering experiments in field conditions. This method provides key data to investigate smouldering combustion dynamics, acquire fire behaviour metrics and obtain indicators for ecological effects of smouldering fires. It is to be applied in all types of undisturbed soils. The experimental protocol is based on a non-electric ignition source and the monitoring system relies on combining both point and surface specific temperature measurements. The methodology has been developed and applied by means of large series of replicate experiments in highly organic soils at the forest–grassland treeline of the Peruvian Andes. The soil tested exhibited weak ignition conditions. However, transition to oxidation phase was observed, with smouldering combustion during 9¿h at 15-cm depth and residence times at temperatures above dehydration of ~22¿h.Peer Reviewe

Fire effects and ecological recovery pathways of tropical montane cloud forests along a time chronosequence

Tropical montane cloud forests (TMCFs) harbour high levels of biodiversity and large carbon stocks. Their location at high elevations make them especially sensitive to climate change, because a warming climate is enhancing upslope species migration, but human disturbance (especially fire) may in many cases be pushing the treeline downslope. TMCFs are increasingly being affected by fire, and the long-term effects of fire are still unknown. Here, we present a 28-year chronosequence to assess the effects of fire and recovery pathways of burned TMCFs, with a detailed analysis of carbon stocks, forest structure and diversity. We assessed rates of change of carbon (C) stock pools, forest structure and tree-size distribution pathways and tested several hypotheses regarding metabolic scaling theory (MST), C recovery and biodiversity. We found four different C stock recovery pathways depending on the selected C pool and time since last fire, with a recovery of total C stocks but not of aboveground C stocks. In terms of forest structure, there was an increase in the number of small stems in the burned forests up to 5–9 years after fire because of regeneration patterns, but no differences on larger trees between burned and unburned plots in the long term. In support of MST, after fire, forest structure appears to approximate steady-state size distribution in less than 30 years. However, our results also provide new evidence that the species recovery of TMCF after fire is idiosyncratic and follows multiple pathways. While fire increased species richness, it also enhanced species dissimilarity with geographical distance. This is the first study to report a long-term chronosequence of recovery pathways to fire suggesting faster recovery rates than previously reported, but at the expense of biodiversity and aboveground C stocks

Cómo avanzar en la conservación de los bosques de Polylepis y su diversidad biológica?

Polylepis is the dominant genus of the high Andean forest vegetation and they have a crucial ecological role. However, these forests are highly endangered and many of their biological aspects are still unknown. In this context, a series of questions were formulated with the aim that their resolution would contribute to a better understanding of Polylepis’dynamics and biological diversity, as well as improve their conservation efforts. Twenty one speakers from the V International Congress of Conservation and Ecology of Polylepis forests participated in the formulation of 67 questions related to these forests. Comments and additional information were received via email and google doc spreadsheet, open to the participants. Afterwards, two workshops were organized with the researchers to formulate, discuss, analyze and define the final list, narrowing down to a total of 40 questions. The questions were categorized into 6 different topics: Taxonomy, Ecology and Biogeography, Genetics, Conservation, Ethnobiology and Climate Change. We hope these questions will be considered as a priority for new research agendas and to define joint efforts for Polylepis forest conservation. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Grou

Plant trait and vegetation data along a 1314 m elevation gradient with fire history in Puna grasslands, Perú

International audienceAlpine grassland vegetation supports globally important biodiversity and ecosystems that are increasingly threatened by climate warming and other environmental changes. Trait-based approaches can support understanding of vegetation responses to global change drivers and consequences for ecosystem functioning. In six sites along a 1314 m elevational gradient in Puna grasslands in the Peruvian Andes, we collected datasets on vascular plant composition, plant functional traits, biomass, ecosystem fluxes, and climate data over three years. The data were collected in the wet and dry season and from plots with different fire histories. We selected traits associated with plant resource use, growth, and life history strategies (leaf area, leaf dry/wet mass, leaf thickness, specific leaf area, leaf dry matter content, leaf C, N, P content, C and N isotopes). The trait dataset contains 3,665 plant records from 145 taxa, 54,036 trait measurements (increasing the trait data coverage of the regional flora by 420%) covering 14 traits and 121 plant taxa (ca. 40% of which have no previous publicly available trait data) across 33 families. © The Author(s) 2024