Facilitating the tropical forest carbon sink: The evolution and function of symbiotic N2 fixation

Lead Research Organisation: University of Leeds
Department Name: Sch of Geography

Abstract

Trees with the ability to access nitrogen fertilizer from the atmosphere (N2 fixers) fill a critical role in supporting tropical forest growth and carbon storage and may become increasingly important as climate changes. Whether N2 fixers will help tropical forests store additional CO2 in the future-thereby offsetting human CO2 emissions-may depend on what controls their function and evolution in ecosystems. To better understand the future role of fixers as climate changes, we can learn by examining how fixers responded to major past global change, deducing why fixers evolved and what factors caused their diversification and spread across forests and other ecosystems. I will address this previously-unposed question using a combination of approaches: 1) establishing a large-scale, long-term fertilization experiment in Panamanian tropical forests to test how nutrients limit forest recovery from disturbance and the ability of N2-fixing trees to facilitate carbon storage; 2) utilizing the largest dataset of fixer prevalence and biodiversity across the Amazon Basin to analyze how nutrients control fixers; 3) combining a recent reconstruction of the evolutionary history (phylogeny) of fixers with a dataset of fixer prevalence and biodiversity across tropical regions globally to determine how nutrients govern the evolution and geographical spread of fixers; and, 4) pairing the fixer phylogeny with a review of ancient geological and climatic events to determine what precipitated the major evolutionary events that led to the modern-day distribution of fixers. This approach is expected to lead a new understanding of the function of fixers throughout earth's history and a better ability to predict how their role may change into the future. New findings will inform policy-makers and the public about the reliability of tropical forests to buffer our CO2 emissions, scientists about the importance of biodiversity and plant function, and practitioners about how to protect and restore ecosystems.

Planned Impact

The research contained within this proposal will produce a number of societal and economic impacts. Determining the role of N2-fixing trees in tropical biogeochemical cycles, both past and present, will help to identify how their functional role will change in the future and how they will support a carbon sink in tropical forests as climate changes. The new information will support public policy making, inform conservation and restoration efforts, improve quality of life and health and impact economic activity.

Decision makers about public policy will benefit from our improved understanding of whether mechanisms exist to facilitate a tropical forest CO2 sink. The proposed research will help to determine whether we can count on N2-fixing trees to supply the nitrogen needed for tropical forests to grow more and store more carbon in response to rising CO2 levels. If we positively identify this mechanism, then scientists will be able to improve predictions about the size of the terrestrial CO2 sink, which will reduce uncertainty about the environmental and social costs of carbon that humans emit. This will in turn help to reduce the uncertainty about setting a price on carbon. In addition, policy-makers will be better informed about the importance of protecting forests and biodiversity, through policies such as REDD+.

The findings will inform conservation and restoration efforts by providing evidence of the role of N2 fixers in forests, including their role in supporting forests from recovery and response to climate change. Conservationists will make improved decisions about what forests to conserve and about the importance of protecting biodiversity and ensuring the presence of N2 fixers. People restoring degraded ecosystems will select species (e.g., particular species of N2 fixers) for a particular environment based on scientific evidence to improve restoration efforts and the quality of the restored habitat.

Human quality of life and health will also be improved because the findings will help us to understand what the future environment will be like with regards to climate change. This could lead to improved social welfare and national security because there will be less uncertainty about what the future climate will be like and what our options are with regards to protecting our future and reducing potential future conflicts.

Finally, this research will have economic impacts because understanding the basic mechanisms of how N2 fixers function within biogeochemical cycles can help improve agricultural production, particularly in developing countries where agricultural practices are currently sub-optimal. By understanding when and why N2-fixing trees bring in additional nitrogen fertilizer from the atmosphere can inform farmers about improving agricultural practices such as through intercropping with N2-fixing trees or crops, and improving agricultural efficiency and minimizing agricultural damage via fertilizer application by rotating crops and using N2 fixers as an alternative source of nitrogen.

Publications

10 25 50

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Batterman SA (2018) Fixing tropical forests. in Nature ecology & evolution

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Dobson A (2023) Plant communities and food webs in Frontiers in Ecology and Evolution

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Epihov DZ (2021) Legume-microbiome interactions unlock mineral nutrients in regrowing tropical forests. in Proceedings of the National Academy of Sciences of the United States of America

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Gurung K (2024) Geographic range of plants drives long-term climate change. in Nature communications

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Kalamandeen M (2020) Limited biomass recovery from gold mining in Amazonian forests in Journal of Applied Ecology

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Levy-Varon JH (2019) Tropical carbon sink accelerated by symbiotic dinitrogen fixation. in Nature communications

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Mills BJW (2018) Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition. in Philosophical transactions of the Royal Society of London. Series B, Biological sciences

 
Description This project has discovered that biodiversity is critical for the functioning of tropical forests because nitrogen-fixing tree species from across the nitrogen fixer phylogeny function in different ways within tropical forests. Nitrogen-fixing trees are particularly important in supporting a tropical carbon sink in forests that are recovering from disturbance such as following deforestation and the abandonment of agriculture. We found that nitrogen-fixing trees have evolved to bring in new nitrogen into tropical ecosystems and help tropical forests recover twice as fast in the first few decades of recovery and store 10% more carbon in the long term. We have also discovered that plants have evolved different relationships with their microbial partners that have important and different impacts on the global environment -- including influencing atmospheric CO2 concentrations and temperature -- over earth's history. We also found that tropical forests that are recovering from agriculture initially are limited by nitrogen and later become limited by phosphorus over secondary succession, while mature tropical forests show little indication of nutrient limitation. Finally, our results indicate that herbivory by insects presents a major cost to nitrogen-fixing trees such that it has limited their function and evolution in tropical forests.
Exploitation Route The outcomes of this funding may be taken forward in several ways. First, the findings will be incorporated into climate change models to improve our predictions of how nitrogen fixer evolution affected the global environment in the past, and how it will affect climate and the environment in the future. Second, our finding that fixers evolved different strategies across the fixer phylogeny may help practitioners aiming to improve reforestation efforts to improve carbon sequestration by providing guidance on the types of species that should be used in reforestation. Third, improving understanding of the role of nitrogen-fixing trees in tropical forests will give guidance on the ability of tropical forest reforestation and protection of existing tropical forests to offer a negative emissions technology to offset anthropogenic carbon emissions. This impacts the energy sector. Finally, offering concrete findings on the role of biodiversity and evolution of the most diverse family of tropical trees offers new insight for the public on why diversity is so important globally.
Sectors Energy

Environment

Other

 
Description Cary Institute of Ecosystem Studies The Lang Assael Family Scientific Innovation Fund Award : Filters of postfire tree regeneration; a carbon-cycle linchpin in the boreal biome
Amount $80,000 (USD)
Organisation Cary Institute of Ecosystem Studies 
Sector Charity/Non Profit
Country United States
Start 01/2023 
End 07/2024
 
Description Climate Research Bursary Fund to Barker
Amount £2,000 (GBP)
Organisation University of Leeds 
Sector Academic/University
Country United Kingdom
Start 05/2018 
End 09/2018
 
Description Fellowship to Zachary James
Amount $2,000 (USD)
Organisation Millbrook Garden Club 
Sector Charity/Non Profit
Country Canada
Start 04/2019 
End 07/2019
 
Description Grant to Arielle Biro from Millbrook Garden Club
Amount $5,000 (USD)
Organisation Millbrook Garden Club 
Sector Charity/Non Profit
Country Canada
Start 11/2020 
 
Description How did the evolution of plants, microbial symbionts and terrestrial nutrient cycles change Earth's long-term climate?
Amount £617,796 (GBP)
Funding ID NE/S009663/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 05/2019 
End 05/2023
 
Description Leeds Anniversary Research Scholarship to Barker
Amount £75,000 (GBP)
Organisation University of Leeds 
Sector Academic/University
Country United Kingdom
Start 09/2016 
End 09/2019
 
Description Leeds-China Scholarship
Amount £60,000 (GBP)
Organisation University of Leeds 
Sector Academic/University
Country United Kingdom
Start 09/2018 
End 09/2021
 
Description Priestley International Centre for Climate grant to Wenguang Tang
Amount £2,500 (GBP)
Organisation University of Leeds 
Department Priestley International Centre for Climate
Sector Academic/University
Country United Kingdom
Start 06/2019 
End 09/2019
 
Description STRI short term fellowship to Barker
Amount $4,500 (USD)
Organisation Smithsonian Institution 
Department Smithsonian Tropical Research Institute
Sector Academic/University
Country Panama
Start 09/2017 
End 01/2018
 
Description Society for Experimental Biology to Barker
Amount £500 (GBP)
Organisation Society for Experimental Biology (SEB) 
Sector Academic/University
Country Global
Start 05/2017 
End 09/2017
 
Title A new way to scale symbiotic nitrogen fixation 
Description I developed a new scaling approach to improve estimates of symbiotic nitrogen fixation 
Type Of Material Improvements to research infrastructure 
Year Produced 2020 
Provided To Others? No  
Impact Submission of grant proposal 
 
Title Computer model for Levy-Varon, Batterman et al 2019 
Description This is a new model available to the public 
Type Of Material Computer model/algorithm 
Year Produced 2019 
Provided To Others? Yes  
Impact This was used in the publication Levy-Varon, Batterman et al 2019 
 
Title Data and code associated with: Trees adjust nutrient acquisition strategies across tropical forest secondary succession. 
Description Nutrient limitation may constrain the ability of recovering and mature tropical forests to serve as a carbon sink. However, it is unclear to what extent trees can utilize nutrient acquisition strategies - especially root phosphatase enzymes and mycorrhizal symbioses - to overcome low nutrient availability during succession. We use a large-scale, full factorial nitrogen and phosphorus fertilization experiment of 76 replicate plots along a tropical forest secondary succession gradient in Panama to test the extent to which trees adjust nutrient acquisition strategies. We show that tropical forests are highly dynamic in adjusting strategies - particularly root phosphatase - during forest recovery, reflecting a shift from strong nitrogen to weak phosphorus limitation over succession. We contextualize these results within a broader meta-analysis, where tree strategies also dynamically respond to nutrients and forest age. Together, our findings indicate that high functional diversity characterizes nutrient strategies in tropical forests, likely critical for alleviating nutrient limitation on the carbon sink.File list:EL_roots_README_09072023_share.pdf. Contains data dictionaries for data tables, project abstract, creators, full list of funders, methodology, citation list and additional project documentation.EL_code.R. Commented code for data transformation, statistical analyses, figures, and meta-analysis.EL_fertilization_root_data.csv. Data for mycorrhizal colonization and root phosphatase activity in response to nitrogen and phosphorus fertilization across four forest age classes in Panama.EL_Plasticity_phosphatase_mycorrhizae.csv. Data for meta-analysis of root phosphatase and mycorrhizal colonization responses to nitrogen and phosphorus additions in tropical forests.EL_secondary_forest_mycorrhizal_colonization_literature_review.csv. Data for literature review on mycorrhizal colonization rates across secondary succession in tropical forests. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
Impact NA 
URL https://caryinstitute.figshare.com/articles/dataset/Data_and_code_associated_with_Trees_adjust_nutri...
 
Title Data for Levy-Varon, Batterman et al 2019 
Description This is a dataset developed for Levy-Varon, Batterman et al 2019 that is available as a supplemental material for the paper. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact This is data made available to the public. 
 
Title Data from: Nitrogen-fixing tree abundance in higher-latitude North America is not constrained by diversity 
Description The rarity of nitrogen (N)-fixing trees in frequently N-limited higher-latitude (here, > 35°) forests is a central biogeochemical paradox. One hypothesis for their rarity is that evolutionary constraints limit N-fixing tree diversity, preventing N-fixing species from filling available niches in higher-latitude forests. Here, we test this hypothesis using data from the USA and Mexico. N-fixing trees comprise only a slightly smaller fraction of taxa at higher vs. lower latitudes (8% vs. 11% of genera), despite 11-fold lower abundance (1.2% vs. 12.7% of basal area). Furthermore, N-fixing trees are abundant but belong to few species on tropical islands, suggesting that low absolute diversity does not limit their abundance. Rhizobial taxa dominate N-fixing tree richness at lower latitudes, whereas actinorhizal species do at higher latitudes. Our results suggest that low diversity does not explain N-fixing trees' rarity in higher-latitude forests. Therefore, N limitation in higher-latitude forests likely results from ecological constraints on N fixation. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Analysis of data published in a paper 
URL https://datadryad.org/stash/dataset/doi:10.5061/dryad.2d4t3
 
Title Data from: Rapid nitrogen fixation by canopy microbiome in tropical forest determined by both phosphorus and molybdenum 
Description Biological nitrogen fixation is critical for the nitrogen cycle of tropical forests, yet we know little about the factors that control the microbial nitrogen-fixers that colonize the microbiome of leaves and branches that make up a forest canopy. Forest canopies are especially prone to nutrient limitation because they are (1) disconnected from soil nutrient pools, and (2) often subject to leaching. Earlier studies have suggested a role of phosphorus and molybdenum in controlling biological N-fixation rates, but experimental confirmation has hitherto been unavailable. We here present the results of a manipulation of canopy nutrient availability . Our findings demonstrate a primary role of phosphorus in constraining overall N-fixation by canopy cyanobacteria, but also a secondary role of molybdenum in determining per-cell fixation rates. A conservative evaluation suggests that canopy fixation can contribute to significant N fluxes at the ecosystem level, especially as bursts following atmospheric inputs of nutrient-rich dust. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Analyses published in a journal 
URL https://datadryad.org/stash/dataset/doi:10.5061/dryad.bt5rc79
 
Title Herbivory rates, species traits and leaf traits across symbiotic nitrogen-fixing and non-fixing species from a Panamanian tropical forest, 2007-2019 
Description This dataset contains measurements of herbivory and the potential controls on herbivory for nitrogen-fixing and non-fixing trees in a mature tropical forest of Panama. Data include herbivory measures on 1,626 leaves from 350 seedlings belonging to 43 species, 23 nitrogen-fixing species, 20 non-fixing species. Herbivory metrics are presented at the leaf and seedling level. The data also includes leaf chemical and physical traits hypothesized to influence herbivory at the species level, and seedling-level traits such as stem length and growth rate. Data were collected in 2017 by measuring leaf area missing on seedlings in the BCI 50 ha plot seedling census in order to determine whether fixers have higher rates of herbivory than non-fixers, and what traits govern herbivory. Data were collected by W. Barker, S.J. Wright, L. Comita, B. Sedio and colleagues. Funders of research generating the data include the Natural Environment Research Council, U.S. National Science Foundation, Leverhulme Trust, British Council, Society of Experimental Biology Company of Biologists, University of Leeds Priestly International Centre for Climate and Smithsonian Tropical Research Institute 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact BA 
URL https://catalogue.ceh.ac.uk/id/67c95112-edee-435f-9355-9d8bab3a5634
 
Title Nitrogen fixation and phosphatase traits in Panamanian trees 
Description This data includes information about nitrogen fixation, phosphatase activity, plant nitrogen and phosphorus demand and soil nitrogen and phosphorus availability of nitrogen-fixing and non-fixing trees from seven species grown in an experimental plantation at the Agua Salud Native Species Plantation, El Giral, Panama (9°12'50.15''N, 79°43'26''W). Data were collected by the Smithsonian Tropical Research Institute and Princeton University and were analysed by the University of Leeds. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Dataset made available to the public 
URL https://catalogue.ceh.ac.uk/documents/3578bae2-4b88-4b2e-93e1-6965dfe1348c
 
Title Organic Acid Exudation Rates. from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the Early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix atmospheric N2 and higher leaf N compared with non-legumes (35-65%) but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric CO2. Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed N to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity. We suggest the high CO2 Early Cenozoic atmosphere further amplified legume weathering. Evolution of legumes with high weathering rates was likely driven by their high demand for phosphorus and micronutrients required for N2-fixation and nodule formation. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/journal_contribution/Organic_Acid_Exudation_Rates_from_N_sub_2_sub_...
 
Title Organic Acid Exudation Rates. from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the Early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix atmospheric N2 and higher leaf N compared with non-legumes (35-65%) but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric CO2. Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed N to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity. We suggest the high CO2 Early Cenozoic atmosphere further amplified legume weathering. Evolution of legumes with high weathering rates was likely driven by their high demand for phosphorus and micronutrients required for N2-fixation and nodule formation. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/journal_contribution/Organic_Acid_Exudation_Rates_from_N_sub_2_sub_...
 
Title Supplementary Figures 1 and 2 from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Weathering processes and the Legume Fossil Record 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/journal_contribution/Supplementary_Figures_1_and_2_from_N_sub_2_sub...
 
Title Supplementary Figures 1 and 2 from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Weathering processes and the Legume Fossil Record 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/journal_contribution/Supplementary_Figures_1_and_2_from_N_sub_2_sub...
 
Title Supplementary Table 1 from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Foliar data 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/dataset/Supplementary_Table_1_from_N_sub_2_sub_-fixing_tropical_leg...
 
Title Supplementary Table 1 from N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic? 
Description Foliar data 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://rs.figshare.com/articles/dataset/Supplementary_Table_1_from_N_sub_2_sub_-fixing_tropical_leg...
 
Title Supplementary material from "N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic?" 
Description Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the Early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix atmospheric N2 and higher leaf N compared with non-legumes (35-65%) but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric CO2. Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed N to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity. We suggest the high CO2 Early Cenozoic atmosphere further amplified legume weathering. Evolution of legumes with high weathering rates was likely driven by their high demand for phosphorus and micronutrients required for N2-fixation and nodule formation. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://figshare.com/collections/Supplementary_material_from_N_sub_2_sub_-fixing_tropical_legume_evo...
 
Title Supplementary material from "N2-fixing tropical legume evolution: a contributor to enhanced weathering through the Cenozoic?" 
Description Fossil and phylogenetic evidence indicates legume-rich modern tropical forests replaced Late Cretaceous palm-dominated tropical forests across four continents during the Early Cenozoic (58-42 Ma). Tropical legume trees can transform ecosystems via their ability to fix atmospheric N2 and higher leaf N compared with non-legumes (35-65%) but it is unclear how their evolutionary rise contributed to silicate weathering, the long-term sink for atmospheric CO2. Here we hypothesize that the increasing abundance of N2-fixing legumes in tropical forests amplified silicate weathering rates by increased input of fixed N to terrestrial ecosystems via interrelated mechanisms including increasing microbial respiration and soil acidification, and stimulating forest net primary productivity. We suggest the high CO2 Early Cenozoic atmosphere further amplified legume weathering. Evolution of legumes with high weathering rates was likely driven by their high demand for phosphorus and micronutrients required for N2-fixation and nodule formation. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact NA 
URL https://figshare.com/collections/Supplementary_material_from_N_sub_2_sub_-fixing_tropical_legume_evo...
 
Description Collaboration with Arielle Biro 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution Expertise, intellectual leadership, laboratory assistance, equipment and space, and ethics training
Collaborator Contribution Field data collection, leading an experiment, intellectual contribution, data analysis, writing
Impact It has led to submission of grant proposal
Start Year 2017
 
Description Collaboration with Ben Hur Marimon and Bia Marimon 
Organisation UNEMAT - Nova Xavantina
Country Brazil 
Sector Academic/University 
PI Contribution Designed research and trained masters students.
Collaborator Contribution Provided facilities, collected data, analyzed data and trained masters students.
Impact collaboration is ongoing
Start Year 2016
 
Description Collaboration with Ben Mills 
Organisation University of Leeds
Department School of Biology
Country United Kingdom 
Sector Academic/University 
PI Contribution I provided a major contribution to identifying the research question, designing the study and writing the manuscript.
Collaborator Contribution Ben Mills provided a major contribution to identifying the research question, designing the study and writing the manuscript. Ben Mills did the modeling.
Impact Manuscript in review at Philosophical Transactions: Mills, B., Batterman, S.A., Field, K. Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition. This research is interdisciplinary, with Ben Mills coming from earth and environment and modeling, Katie Fields coming from biology, and me coming from geography and ecology.
Start Year 2016
 
Description Collaboration with Duncan Menge 
Organisation Columbia University
Country United States 
Sector Academic/University 
PI Contribution I am bringing expertise to a new project with Duncan Menge and his PhD student Palani Akana that was informed by this NERC project.
Collaborator Contribution They bring expertise and effort.
Impact The project is in development.
Start Year 2019
 
Description Collaboration with Efrat Sheffer 
Organisation Hebrew University of Jerusalem
Country Israel 
Sector Academic/University 
PI Contribution I helped to formulate and design the study on evolution of nitrogen fixation strategies across latitudinal gradients. I helped to write the paper.
Collaborator Contribution Efrat Sheffer led the development and analysis of the theoretical model and took the lead on writing the paper (Sheffer, Batterman et al. 2015, Nature Plants).
Impact Sheffer E, Batterman S, Levin S, Hedin L. (2015). Biome-scale nitrogen fixation strategies selected by climatic constraints on nitrogen cycle. Nature Plants, 1 (12), pp. 15182 (Commentary) Houlton, B. Z. NITROGEN FIXATION Fixing evolution in global forests. Nature Plants 1, doi:Artn 15205 10.1038/Nplants.2015.205 (2015). https://www.princeton.edu/main/news/archive/S44/88/96G13/index.xml?section=newsreleases
Start Year 2015
 
Description Collaboration with Joe Wright 
Organisation Smithsonian Institution
Department Smithsonian Tropical Research Institute
Country Panama 
Sector Academic/University 
PI Contribution Leading effort to evaluate how fixation rates across the fixer phylogeny are governed by soil nutrients by collecting data on fixation across the fertilization experiment at the Gigante site, to pair with the new experiment in young forests developed as part of the NERC fellowship
Collaborator Contribution Provided dataset collected over 20 years, access to sites, assistance from field technician, guidance on experimental design
Impact No outputs yet
Start Year 2017
 
Description Collaboration with Joice Ferreira, Erika Berenguer, Jos Barlow, Rodrigo Oliveira 
Organisation Brazilian Agricultural Research Corporation
Country Brazil 
Sector Public 
PI Contribution Developing project, supervision of masters student, training
Collaborator Contribution Data collection, analysis and synthesis
Impact No research outcomes yet
Start Year 2016
 
Description Collaboration with Joice Ferreira, Erika Berenguer, Jos Barlow, Rodrigo Oliveira 
Organisation Lancaster University
Country United Kingdom 
Sector Academic/University 
PI Contribution Developing project, supervision of masters student, training
Collaborator Contribution Data collection, analysis and synthesis
Impact No research outcomes yet
Start Year 2016
 
Description Collaboration with Joice Ferreira, Erika Berenguer, Jos Barlow, Rodrigo Oliveira 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution Developing project, supervision of masters student, training
Collaborator Contribution Data collection, analysis and synthesis
Impact No research outcomes yet
Start Year 2016
 
Description Collaboration with Katie Field 
Organisation University of Leeds
Department Sustainability Service
Country United Kingdom 
Sector Academic/University 
PI Contribution I provided a major contribution to identifying the research question, designing the study and writing the manuscript.
Collaborator Contribution Katie Field provided a major contribution to identifying the research question, designing the study and writing the manuscript. Katie Field provided experimental data.
Impact Manuscript in review at Philosophical Transactions: Mills, B., Batterman, S.A., Field, K. Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition. This collaboration is multi-disciplinary with Katie Field coming from biology, Ben Mills coming from earth and environment, and me coming from geography and ecology.
Start Year 2016
 
Description Collaboration with Klaus Winter 
Organisation Smithsonian Institution
Department Smithsonian Tropical Research Institute
Country Panama 
Sector Academic/University 
PI Contribution Our team designed and conducted an experiment to evaluate the constraints by herbivory or symbiotic nitrogen fixation
Collaborator Contribution Winter provided guidance in experimental design, conduct and analysis, and the facilities and technician help for the experiment
Impact No outputs yet
Start Year 2017
 
Description Collaboration with Liza Comita and Steve Hubbell 
Organisation University of California, Los Angeles (UCLA)
Country United States 
Sector Academic/University 
PI Contribution My team is leading the analysis of a large dataset collected and maintained by Comita and Hubbell to understand the evolution of fixation in tropical forests and the role of herbivory.
Collaborator Contribution They have provided the data, and Comita has provided code and assistance in the data analysis.
Impact The collaboration is in its early stages, so there are no outputs yet.
Start Year 2017
 
Description Collaboration with Liza Comita and Steve Hubbell 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution My team is leading the analysis of a large dataset collected and maintained by Comita and Hubbell to understand the evolution of fixation in tropical forests and the role of herbivory.
Collaborator Contribution They have provided the data, and Comita has provided code and assistance in the data analysis.
Impact The collaboration is in its early stages, so there are no outputs yet.
Start Year 2017
 
Description Collaboration with Michelle Wong 
Organisation Cary Institute of Ecosystem Studies
Country United States 
Sector Charity/Non Profit 
PI Contribution Michelle started as a postdoctoral research associate working with me on research relating to the NERC-funded project. She is building upon the platform developed by the NERC project.
Collaborator Contribution Michelle brings expertise and effort to the partnership.
Impact No outcomes have emerged yet
Start Year 2019
 
Description Collaboration with Nina Wurzburger 
Organisation University of Georgia
Country United States 
Sector Academic/University 
PI Contribution Expertise, intellectual input, data
Collaborator Contribution Expertise, intellectual input, data, computing power, training of staff
Impact Facilitated research following training of postdoctoral researcher and PhD student; led to submission of grant proposal
Start Year 2020
 
Description Collaboration with Palani Akana 
Organisation Columbia University
Country United States 
Sector Academic/University 
PI Contribution I am serving as a PhD committee member for this PhD student and using the expertise and knowledge I have gained from this NERC project to give guidance and inform his research plans.
Collaborator Contribution This student is bringing expertise and effort to the partnership.
Impact I participated in the exam for his PhD qualification.
Start Year 2019
 
Description Collaboration with Powell working group 
Organisation US Geological Survey
Country United States 
Sector Public 
PI Contribution Intellectual leadership, data collection
Collaborator Contribution Intellectual leadership, data collection, writing
Impact Manuscript forthcoming
Start Year 2019
 
Description Collaboration with Yale Center for Natural Carbon Capture workshop on below ground restoration 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution Brought expertise on symbiotic nitrogen fixation, plant nutrient strategies, nutrient limitation and tropical forest carbon recovery following disturbance
Collaborator Contribution Expertise on below ground restoration
Impact grant proposals, manuscripts, etc.
Start Year 2023
 
Description Collaboration with Yale Center for Natural Carbon Capture workshop on fertility and tropical forest carbon 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution Expertise on tropical carbon sink, nutrients and plant nutrient strategies
Collaborator Contribution Expertise on tropical carbon sink and nutrients
Impact Grant proposals and manuscripts
Start Year 2023
 
Description Collaboration with Yong Zhou 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution Intellectual leadership, training, laboratory equipment
Collaborator Contribution Intellectual leadership, writing
Impact Led to submission of grant proposal
Start Year 2020
 
Description Collaboration with Yong Zhou 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution We are using what we have learned from the NERC-funded project to inform research in the Southern African savanna biome. We are training Yong Zhou on techniques that he will use to collect data in this new system.
Collaborator Contribution Yong Zhou is bringing expertise in the savanna biome and field efforts to the partnership.
Impact No outcomes have emerged yet as the collaboration is just starting.
Start Year 2019
 
Description Contribution to ELTI course 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Assisted with training course for practitioners and politicians surrounding the importance of tropical forests for the environment and best practices for reforestation. The training course actively engaged students who went on to implement best practice recommendations for reforestation generated from my research into their own reforestation projects and government policy.
Year(s) Of Engagement Activity 2016
 
Description Participation in British Ecological Society workshop on highlight topics development 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact 20 people participated in a workshop to develop ideas for highlight topics proposals for NERC. My idea was selected to be developed, and was submitted to NERC in summer 2019.
Year(s) Of Engagement Activity 2019
 
Description Participation in INCyTe -- a working group that is linking field researchers with modellers to improve predictions of the terrestrial carbon sink 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact 100 postgraduates, postdoctoral researchers and academics learned about and discussed better ways to link field based research with global dynamic vegetation models
Year(s) Of Engagement Activity 2020
 
Description Participation in Powell Working Group on improving estimate of global nitrogen fixation 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact 18 people participated in a working group whose outcomes are ongoing and will be disseminated to global modelers, the general public and practitioners.
Year(s) Of Engagement Activity 2019,2020
 
Description Participation in TropiRoot 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact 50 people discussed root traits and their effect on terrestrial productivity and plants
Year(s) Of Engagement Activity 2020
 
Description Press release for Levy-Baron, Batterman et al 2019 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact This press release was widely distributed to the general public through the associated press and through the social media accounts and website of the Cary Institute of Ecosystem Studies
Year(s) Of Engagement Activity 2020
 
Description Press release for Nature Plant study 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Our Nature Plant study was highlighted in press releases and the media:

http://blog.pnas.org/2015/12/journal-club-model-shows-why-trees-to-fix-nitrogen-where-they-do-offering-insights-with-big-implications-for-the-biosphere/

https://www.princeton.edu/main/news/archive/S44/88/96G13/index.xml?section=topstories

http://www.nature.com/articles/nplants2015205?WT.feed_name=subjects_plant-symbiosis
Year(s) Of Engagement Activity 2015
URL http://blog.pnas.org/2015/12/journal-club-model-shows-why-trees-to-fix-nitrogen-where-they-do-offeri...
 
Description Public press coverage of Batterman et al 2018 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Press release for Ecology Letters study
Year(s) Of Engagement Activity 2018
 
Description Public press coverage of Mills et al 2018 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Press coverage (BBC, Guardian, Botany One, etc.) of Mills et al. 2018
Year(s) Of Engagement Activity 2018