Publications
53 results found
Waring BG, 2024, The potential for enhanced soil carbon sequestration to mitigate climate change
This briefing note assesses the potential for soil carbon sequestration to mitigate climate change, summarising the basic science and providing an overview of best practices for measuring and modifying soil carbon stocks. We also set out recommendations for policy makers, examining UK land use policies as a case study.
Li S, Waring B, Powers J, et al., 2024, Tropical dry forest response to nutrient fertilization: a model validation and sensitivity analysis, Biogeosciences, Vol: 21, Pages: 455-471, ISSN: 1726-4170
Soil nutrients, especially nitrogen (N) and phosphorus (P), regulate plant growth and hence influence carbon fluxes between the land surface and atmosphere. However, how forests adjust biomass partitioning to leaves, wood, and fine roots in response to N and/or P fertilization remains puzzling. Recent work in tropical forests suggests that trees increase fine root production under P fertilization, but it is unclear whether mechanistic models can reproduce this dynamic. In order to better understand mechanisms governing nutrient effects on plant allocation and improve models, we used the nutrient-enabled ED2 model to simulate a fertilization experiment being conducted in a secondary tropical dry forest in Costa Rica. We evaluated how different allocation parameterizations affected model performance. These parameterizations prescribed a linear relationship between relative allocation to fine roots and soil P concentrations. The slope of the linear relationship was allowed to be positive, negative, or zero. Some parameterizations realistically simulated leaf, wood, and fine root production, and these parameterizations all assumed a positive relationship between relative allocation to fine roots and soil P concentration. Model simulations of a 30-year timeframe indicated strong sensitivity to parameterization and fertilization treatment. Without P fertilization, the simulated aboveground biomass (AGB) accumulation was insensitive to the parameterization. With P fertilization, the model was highly sensitive to the parameterization and the greatest AGB accumulation occurred when relative allocation to fine roots was independent of soil P. Our study demonstrates the need for simultaneous measurements of leaf, wood, and fine root production in nutrient fertilization experiments and for longer-term experiments. Models that do not accurately represent allocation to fine roots may be highly biased in their simulations of AGB, especially on multi-decadal timescales.
Saunders T, Adkins J, Beard KH, et al., 2023, Herbivores influence biogeochemical processes by altering litter quality and quantity in a subarctic wetland, Biogeochemistry, Vol: 166, Pages: 67-85, ISSN: 0168-2563
Global change drivers that modify the quality and quantity of litter inputs to soil affect greenhouse gas fluxes, and thereby constitute a feedback to climate change. Carbon cycling in the Yukon–Kuskokwim (Y–K) River Delta, a subarctic wetland system, is influenced by landscape variations in litter quality and quantity generated by herbivores (migratory birds) that create ‘grazing lawns’ of short stature, nitrogen-rich vegetation. To identify the mechanisms by which these changes in litter inputs affect soil carbon balance, we independently manipulated qualities and quantities of litter representative of levels found in the Y–K Delta in a fully factorial microcosm experiment. We measured CO2 fluxes from these microcosms weekly. To help us identify how litter inputs influenced greenhouse gas fluxes, we sequenced soil fungal and bacterial communities, and measured soil microbial biomass carbon, dissolved carbon, inorganic nitrogen, and enzyme activity. We found that positive correlations between litter input quantity and CO2 flux were dependent upon litter type, due to differences in litter stoichiometry and changes to the structure of decomposer communities, especially the soil fungi. These community shifts were particularly pronounced when litter was added in the form of herbivore feces, and in litter input treatments that induced nitrogen limitation (i.e., senesced litter). The sensitivity of carbon cycling to litter quality and quantity in this system demonstrates that herbivores can strongly impact greenhouse gas fluxes through their influence on plant growth and tissue chemistry. Graphical abstract: [Figure not available: see fulltext.]
Liang G, Reed SC, Stark JM, et al., 2023, Unraveling mechanisms underlying effects of wetting-drying cycles on soil respiration in a dryland, BIOGEOCHEMISTRY, ISSN: 0168-2563
Murray J, Smith AP, Simpson M, et al., 2023, Climate, as well as branch-level processes, drive canopy soil abundance and chemistry, GEODERMA, Vol: 438, ISSN: 0016-7061
Liang G, Stark J, Waring B, 2023, Mineral reactivity determines root effects on soil organic carbon, Nature Communications, Vol: 14, Pages: 1-10, ISSN: 2041-1723
Modern conceptual models of soil organic carbon (SOC) cycling focus heavily on the microbe-mineral interactions that regulate C stabilization. However, the formation of ‘stable’ (i.e. slowly cycling) soil organic matter, which consists mainly of microbial residues associated with mineral surfaces, is inextricably linked to C loss through microbial respiration. Therefore, what is the net impact of microbial metabolism on the total quantity of C held in the soil? To address this question, we constructed artificial root-soil systems to identify controls on C cycling across the plant-microbe-mineral continuum, simultaneously quantifying the formation of mineral-associated C and SOC losses to respiration. Here we show that root exudates and minerals interacted to regulate these processes: while roots stimulated respiratory C losses and depleted mineral-associated C pools in low-activity clays, root exudates triggered formation of stable C in high-activity clays. Moreover, we observed a positive correlation between the formation of mineral-associated C and respiration. This suggests that the growth of slow-cycling C pools comes at the expense of C loss from the system.
Beidler KV, Powers JS, Dupuy-Rada JM, et al., 2023, Seasonality regulates the structure and biogeochemical impact of ectomycorrhizal fungal communities across environmentally divergent neotropical dry forestsPalabras clave, JOURNAL OF ECOLOGY, Vol: 111, Pages: 1598-1613, ISSN: 0022-0477
Waring B, Gurgel A, Koberle A, et al., 2023, Natural Climate Solutions must embrace multiple perspectives to ensure synergy with sustainable development, Frontiers in Climate, Vol: 5, Pages: 1-7, ISSN: 2624-9553
To limit global warming to well below 2°C, immediate emissions reductions must be coupled with active removal of greenhouse gases from the atmosphere. 'Natural Climate Solutions' (NCS) achieve atmospheric CO2 reduction through the conservation, restoration, or altered management of natural ecosystems, 1,2 with enormous potential to deliver 'win-win-win' outcomes for climate, nature and society.Yet the supply of high-quality NCS projects does not meet market demand, and projects already underway often fail to deliver their promised benefits, due to a complex set of interacting ecological, social, and financial constraints. How can these cross-sectoral challenges be surmounted? Here we draw from expert elicitation surveys and workshops with professionals across the ecological, sociological, and economic sciences, evaluating differing perspectives on NCS, and suggesting how these might be integrated to address urgent environmental challenges. We demonstrate that funders' perceptions of operational, political, and regulatory risk strongly shape the kinds of NCS projects that are implemented, and the locations where they occur. Because of this, greenhouse gas removal through NCS may fall far short of technical potential.Moreover, socioecological co-benefits of NCS are unlikely to be realized unless the local communities engaged with these projects are granted ownership over implementation and outcomes.
Gutierrez GV, Perez-Aviles D, Raczka N, et al., 2023, Throughfall exclusion and fertilization effects on tropical dry forest tree plantations, a large-scale experiment, BIOGEOSCIENCES, Vol: 20, Pages: 2143-2160, ISSN: 1726-4170
Waring BG, 2023, Grand challenges in ecosystem restoration, Frontiers in Environmental Science, Vol: 11
Waring B, Smith K, Belluau M, et al., 2022, Soil carbon pools are affected by species identity and productivity in a tree common garden experiment, Frontiers in Forests and Global Change, Vol: 5, ISSN: 2624-893X
The formation and turnover of soil organic carbon (C), the largest terrestrial C pool, is strongly impacted by the ultimate source of that C: leaves, wood, roots, and root exudates. The quantity and quality of these inputs is determined by the identity of the plants involved. Yet substantial uncertainty surrounds the complex relationships among plant traits and soil C, precluding efforts to maximize whole-ecosystem C uptake in nature-based climate mitigation scenarios. In this study, we leveraged a biodiversity-ecosystem function experiment with trees (IDENT) to explore the effects of interspecific variation in plant traits on soil C dynamics in the very early stages of stand development (9 years since planting). Mineral soil C stocks to 5 cm depth were quantified in monospecific plots of 19 tree species planted on a former agricultural field, and analyzed in relation to tree growth and functional traits. We found that tree species identity affected soil bulk density and, to a lesser extent, the carbon content of the topsoil, and thereby total C pools. Among species and across plots, mineral soil C stocks were positively correlated with rates of tree growth and were significantly larger beneath broadleaf trees with “fast” functional traits vs. conifers with more conservative leaf traits, when comparisons were made over equivalent soil depth increments. Thus, plant functional traits mediate interspecific differences in productivity, which in turn influence the magnitude of belowground C stocks. These results highlight important linkages between above- and belowground carbon cycles in the earliest stages of afforestation.
Liang G, Sun P, Waring BG, 2022, Nitrogen agronomic efficiency under nitrogen fertilization does not change over time in the long term: Evidence from 477 global studies, SOIL & TILLAGE RESEARCH, Vol: 223, ISSN: 0167-1987
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- Citations: 5
Waring B, Gee A, Liang G, et al., 2022, A quantitative analysis of microbial community structure-function relationships in plant litter decay, iScience, Vol: 25, Pages: 1-13, ISSN: 2589-0042
Soil microbes play a central role in ecosystem element cycling. Yet a central question in microbial ecology remains unanswered: to what extent does the taxonomic composition of soil microbial communities mediate biogeochemical process rates? In this quantitative review, we explore the mechanisms that lead to variation in the strength of microbial community structure-function relationships over space and time. To evaluate these mechanisms, we conduct a meta-analysis of studies that have monitored the decomposition of sterilized plant litter inoculated with different microbial assemblages. We find that the influence of microbial community composition on litter decay is pervasive and strong, rivalling in magnitude the influence of litter chemistry on decomposition. However, no single environmental or experimental attribute was correlated with variation in the inoculum effect. These results emphasize the need to better understand ecological dynamics within microbial communities, particularly emergent features such as cross-feeding networks, to improve predictions of soil biogeochemical function.
Foley KM, Beard KH, Atwood TB, et al., 2022, Herbivory changes soil microbial communities and greenhouse gas fluxes in a high-latitude wetland, MICROBIAL ECOLOGY, Vol: 83, Pages: 127-136, ISSN: 0095-3628
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- Citations: 4
Waring BG, Smith KR, Grote EE, et al., 2021, Climatic Controls on Soil Carbon Accumulation and Loss in a Dryland Ecosystems, JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, Vol: 126, ISSN: 2169-8953
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- Citations: 2
Waring BG, Sulman BN, Reed S, et al., 2021, Response to "Connectivity and pore accessibility in models of soil carbon cycling", GLOBAL CHANGE BIOLOGY, Vol: 27, Pages: E15-E16, ISSN: 1354-1013
Vargas GG, Brodribb TJ, Dupuy JM, et al., 2021, Beyond leaf habit: generalities in plant function across 97 tropical dry forest tree species, NEW PHYTOLOGIST, Vol: 232, Pages: 148-161, ISSN: 0028-646X
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- Citations: 18
Liang G, Luo Y, Zhou Z, et al., 2021, Nitrogen effects on plant productivity change at decadal time-scales, Global Ecology and Biogeography Letters, Vol: 30, Pages: 2488-2499, ISSN: 0960-7447
AimAlthough some long-term studies have been conducted to quantify the impacts of nitrogen (N) on plant productivity, uncertainties remain regarding whether these impacts change over time and the underlying mechanisms. By overlooking this, we might over- or underestimate the impacts of N on terrestrial ecosystems. Our goal was to determine whether the impacts of N on plant productivity change in the long term and what controls these dynamics.LocationGlobal.Time period1999–2018.Major taxa studiedEffects of N on plant productivity.MethodsWe synthesized 63 N addition studies with duration ≥ 8 years in natural terrestrial ecosystems.ResultsOur results showed temporally dynamic impacts of N on plant productivity in terrestrial ecosystems. The interannual coefficient of variation (CV) of N impacts ranged from 19 to 768% across 63 studies, with higher variability in acidic soils. Moreover, a substantial proportion (44%) of studies showed evidence of a consistent directional change in the strength of the impacts of N over time. The direction of change varied with biome type (forests, decrease; grasslands and shrublands, increase). The temporal pattern of the impacts of N was mostly responsive to mean annual precipitation (MAP), mean annual temperature (MAT) and initial soil pH, which accounted for 24%, 19% and 19% of the variation, respectively.Main conclusionsOur findings indicate that temporally dynamic impacts of long-term N addition on plant productivity and large fluctuations of the impacts of N between years are generally observed among studies in terrestrial ecosystems. Therefore, not only the magnitude of N impacts on plant productivity, but also their temporal pattern and variability should be considered in future experimental and model research.
Waring BG, De Guzman ME, Du DV, et al., 2021, Soil biogeochemistry across Central and South American tropical dry forests, ECOLOGICAL MONOGRAPHS, Vol: 91, ISSN: 0012-9615
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- Citations: 17
Waring BG, Sulman BN, Reed S, et al., 2021, Response to `Stochastic and deterministic interpretation of pool models', GLOBAL CHANGE BIOLOGY, Vol: 27, Pages: e11-e12, ISSN: 1354-1013
Waring BG, Sulman BN, Reed S, et al., 2020, From pools to flow: The PROMISE framework for new insights on soil carbon cycling in a changing world, GLOBAL CHANGE BIOLOGY, Vol: 26, Pages: 6631-6643, ISSN: 1354-1013
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- Citations: 46
Waring B, Neumann M, Prentice IC, et al., 2020, What role can forests play in tackling climate change?, What role can forests play in tackling climate change?, www.imperial.ac.uk/grantham, Publisher: Grantham Institute, Discussion paper 6
This discussion paper consolidates knowledge on the potential environmental, economic and societal benefits of using trees to reduce the concentration of carbon dioxide in the atmosphere. It highlights areas for further research and defines the limits of trees’ ability to halt the progress of climate change.
Hulshof CM, Waring BG, Powers JS, et al., 2020, Trait-based signatures of cloud base height in a tropical cloud forest, AMERICAN JOURNAL OF BOTANY, Vol: 107, Pages: 886-894, ISSN: 0002-9122
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- Citations: 3
Waring B, Neumann M, Prentice IC, et al., 2020, Forests and decarbonization: roles of natural and planted forests, Frontiers in Forests and Global Change, Vol: 3, ISSN: 2624-893X
The severe consequences of human disruptions to the global carbon cycle have prompted intense interest in strategies to reduce atmospheric CO2 concentrations. Because growing forests capture CO2 in their biomass and soils, large-scale tree planting efforts have been advertised as a viable way to counteract anthropogenic emissions as part of net-zero emission strategies. Here, we assess the potential impact of reforestation and afforestation on the global climate system, and identify ecological, economic, and societal implications of such efforts.
Wooliver R, Pellegrini AFA, Waring B, et al., 2019, Changing perspectives on terrestrial nitrogen cycling: The importance of weathering and evolved resource-use traits for understanding ecosystem responses to global change, FUNCTIONAL ECOLOGY, Vol: 33, Pages: 1818-1829, ISSN: 0269-8463
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- Citations: 11
Medvigy D, Wang G, Zhu Q, et al., 2019, Observed variation in soil properties can drive large variation in modelled forest functioning and composition during tropical forest secondary succession, NEW PHYTOLOGIST, Vol: 223, Pages: 1820-1833, ISSN: 0028-646X
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- Citations: 29
Waring BG, Perez-Aviles D, Murray JG, et al., 2019, Plant community responses to stand-level nutrient fertilization in a secondary tropical dry forest, ECOLOGY, Vol: 100, ISSN: 0012-9658
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- Citations: 27
Smith KR, Waring BG, 2019, Broad-Scale Patterns of Soil Carbon (C) Pools and Fluxes Across Semiarid Ecosystems are Linked to Climate and Soil Texture, ECOSYSTEMS, Vol: 22, Pages: 742-753, ISSN: 1432-9840
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- Citations: 9
Werden LK, Waring BG, Smith-Martin CM, et al., 2018, Tropical dry forest trees and lianas differ in leaf economic spectrum traits but have overlapping water-use strategies, TREE PHYSIOLOGY, Vol: 38, Pages: 517-530, ISSN: 0829-318X
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- Citations: 35
Averill C, Waring B, 2018, Nitrogen limitation of decomposition and decay: How can it occur?, Global Change Biology, Vol: 24, Pages: 1417-1427, ISSN: 1354-1013
The availability of nitrogen (N) is a critical control on the cycling and storage of soil carbon (C). Yet, there are conflicting conceptual models to explain how N availability influences the decomposition of organic matter by soil microbial communities. Several lines of evidence suggest that N availability limits decomposition; the earliest stages of leaf litter decay are associated with a net import of N from the soil environment, and both observations and models show that high N organic matter decomposes more rapidly. In direct contrast to these findings, experimental additions of inorganic N to soils broadly show a suppression of microbial activity, which is inconsistent with N limitation of decomposition. Resolving this apparent contradiction is critical to representing nutrient dynamics in predictive ecosystem models under a multitude of global change factors that alter soil N availability. Here, we propose a new conceptual framework, the Carbon, Acidity, and Mineral Protection hypothesis, to understand the effects of N availability on soil C cycling and storage and explore the predictions of this framework with a mathematical model. Our model simulations demonstrate that N addition can have opposing effects on separate soil C pools (particulate and mineral‐protected carbon) because they are differentially affected by microbial biomass growth. Moreover, changes in N availability are frequently linked to shifts in soil pH or osmotic stress, which can independently affect microbial biomass dynamics and mask N stimulation of microbial activity. Thus, the net effect of N addition on soil C is dependent upon interactions among microbial physiology, soil mineralogy, and soil acidity. We believe that our synthesis provides a broadly applicable conceptual framework to understand and predict the effect of changes in soil N availability on ecosystem C cycling under global change.
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