scholarly journals Global Evaluation of the Ecosystem Demography Model (ED v3.0)

2021 ◽  
Author(s):  
Lei Ma ◽  
George Hurtt ◽  
Lesley Ott ◽  
Ritvik Sahajpal ◽  
Justin Fisk ◽  
...  
Keyword(s):  
Vegetation Dynamics ◽  
Gross Primary Production ◽  
Critical Role ◽  
Terrestrial Ecosystems ◽  
Global Evaluation ◽  
Ecological Processes ◽  
Modelling Framework ◽  
Global Calibration ◽  
Global Patterns ◽  
Uncertain Future

Abstract. Terrestrial ecosystems play a critical role in the global carbon cycle but have highly uncertain future dynamics. Ecosystem modelling that includes the scaling-up of underlying mechanistic ecological processes has the potential  to improve the accuracy of future projections, while retaining key process-level detail. Over the past two decades,  multiple modelling advances have been made to meet this challenge, including the Ecosystem Demography (ED)  model and its derivatives including ED2 and FATES. Here, we present the global evaluation of the Ecosystem  Demography model (ED v3.0), which likes its predecessors features the formal scaling of physiological processes of  individual-based vegetation dynamics to ecosystem scales, together with integrated submodules of soil  biogeochemistry and soil hydrology, while retaining explicit tracking of vegetation 3-D structure. This new version  builds on previous versions and provides the first global calibration and evaluation, global tracking of the effects of  climate and land-use change on vegetation 3-D structure, new spin-up process and input datasets, as well as  numerous other advances. Model evaluation was performed with respect to a set of important benchmarking  datasets, and model estimates were within observational constraints for multiple key variables including: (i) global  patterns of dominant plant functional types (broadleaf vs evergreen); (ii) spatial distribution, seasonal cycle, and  interannual trends of global Gross Primary Production (GPP); (iii) global interannual variability of Net Biome  Production (NBP); and (iv) global patterns of vertical structure including leaf area and canopy height. With this  global model version, it is now possible to simulate vegetation dynamics from local to global scales and from seconds to centuries, with a consistent mechanistic modelling framework amendable to data from multiple  traditional and new remote sensing sources, including lidar.

Response of tropical terrestrial gross primary production to the super El Niño event in 2015

2020 ◽  
Author(s):  
Jiawen Zhu ◽  
Minghua Zhang ◽  
Yao Zhang ◽  
Xiaodong Zeng ◽  
Xiangming Xiao
Keyword(s):  
Carbon Cycle ◽  
Primary Production ◽  
Tropical Forests ◽  
Gross Primary Production ◽  
Critical Role ◽  
Terrestrial Ecosystem ◽  
Terrestrial Ecosystems ◽  
Climate Feedback ◽  
Test Case ◽  
Climate Data

<p>The Gross Primary Production (GPP) in tropical terrestrial ecosystems plays a critical role in the global carbon cycle and climate change. The strong 2015–2016 El Niño event offers a unique opportunity to investigate how GPP in the tropical terrestrial ecosystems responds to climatic forcing. This study uses two GPP products and concurrent climate data to investigate the GPP anomalies and their underlying causes. We find that both GPP products show an enhanced GPP in 2015 for the tropical terrestrial ecosystem as a whole relative to the multi-year mean of 2001–2015, and this enhancement is the net result of GPP increase in tropical forests and decrease in non-forests. We show that the increased GPP in tropical forests during the El Nino event is consistent with increased photosynthesis active radiation as a result of a reduction in clouds, while the decreased GPP in non-forests is consistent with increased water stress as a result of a reduction of precipitation and an increase of temperature. These results reveal the strong coupling of ecosystem and climate that is different in forest and non-forest ecosystems, and provide a test case for carbon cycle parameterization and carbon-climate feedback simulation in models.</p>

scholarly journals Linking Genes to Traits in Fungi

2021 ◽  
Author(s):  
A. L. Romero-Olivares ◽  
E. W. Morrison ◽  
A. Pringle ◽  
S. D. Frey
Keyword(s):  
Organic Matter ◽  
Nitrogen Uptake ◽  
Brown Rot ◽  
Terrestrial Ecosystems ◽  
Organic Matter Decomposition ◽  
Gene Frequencies ◽  
Ecological Processes ◽  
Linked Gene ◽  
Carbon Cycles ◽  
Brown Rot Fungi

AbstractFungi are mediators of the nitrogen and carbon cycles in terrestrial ecosystems. Examining how nitrogen uptake and organic matter decomposition potential differs in fungi can provide insight into the underlying mechanisms driving fungal ecological processes and ecosystem functioning. In this study, we assessed the frequency of genes encoding for specific enzymes that facilitate nitrogen uptake and organic matter decomposition in 879 fungal genomes with fungal taxa grouped into trait-based categories. Our linked gene-trait data approach revealed that gene frequencies vary across and within trait-based groups and that trait-based categories differ in trait space. We present two examples of how this linked gene-trait approach can be used to address ecological questions. First, we show that this type of approach can help us better understand, and potentially predict, how fungi will respond to environmental stress. Specifically, we found that trait-based categories with high nitrogen uptake gene frequency increased in relative abundance when exposed to high soil nitrogen enrichment. Second, by comparing frequencies of nitrogen uptake and organic matter decomposition genes, we found that most ectomycorrhizal fungi in our dataset have similar gene frequencies to brown rot fungi. This demonstrates that gene-trait data approaches can shed light on potential evolutionary trajectories of life history traits in fungi. We present a framework for exploring nitrogen uptake and organic matter decomposition gene frequencies in fungal trait-based groups and provide two concise examples on how to use our framework to address ecological questions from a mechanistic perspective.

Sensitivity of global gross primary production to elevated CO2

2021 ◽  
Author(s):  
Wenjia Cai ◽  
Iain Colin Prentice
Keyword(s):  
Field Experiments ◽  
Carbon Sink ◽  
Gross Primary Production ◽  
Light Response ◽  
Terrestrial Ecosystems ◽  
Percentage Increase ◽  
Terrestrial Plants ◽  
Fertilization Effect ◽  
Vegetation Models ◽  
The Impact

<p>Terrestrial ecosystems have accounted for more than half of the global carbon sink during the past decades and offset 25%-30% of current anthropogenic CO<sub>2</sub> emissions. The projected increase in CO<sub>2</sub> concentration will depend on the magnitude of terrestrial plants’ feedback to CO<sub>2</sub>: i.e. the sensitivity of plant carbon uptake in response to elevated CO<sub>2</sub>, and the strength of the CO<sub>2</sub> fertilization effect (CFE) in a changing (and warming) environment. Projecting vegetation responses to future increases in CO<sub>2</sub> concentration under climate change is a major uncertainty, as ecosystem models, field experiments and satellite-based models show large disagreements. In this study, using a recently developed, parameter-sparse model (the ‘P model’), we assess the sensitivity of GPP to increasing CO<sub>2</sub> under idealized conditions, in comparison with other vegetation models and field experiments. We investigate the impact of two central parameters, the ratio of J<sub>max </sub>to V<sub>cmax</sub> (at a common temperature) and the curvature of the light response curve, on the sensitivity of GPP to CO<sub>2</sub>. We also quantified the spatial-temporal trend of CFE using the β factor, defined as the percentage increase in GPP in response to a 100-ppm increase in atmospheric CO<sub>2</sub> concentration over a defined period. We show how modelled β has changed over the satellite era, and infer the possible effect of climatic variables on changes of CFE from spatial patterns of the modelled trend in β.</p>

Serpentine Plant Assemblages: A Global Overview

2007 ◽  
Author(s):  
Earl B. Alexander ◽  
Roger G. Coleman ◽  
Todd Keeler-Wolfe ◽  
Susan P. Harrison
Keyword(s):  
Fire History ◽  
New Caledonia ◽  
Physical Factors ◽  
Ecological Processes ◽  
Global Trends ◽  
The World ◽  
Serpentine Vegetation ◽  
Global Patterns ◽  
Plant Assemblages ◽  
Local Levels

Serpentine substrates are found in many parts of the world, but there is considerable variation in the structure, composition, and diversity of the flora they support. To place western North America in a worldwide context, this chapter provides a brief sketch of global patterns in serpentine plant life, drawing on the reviews by Brooks (1987), Baker et al. (1992), and Roberts and Proctor (1992), as well as other sources. Following this is an overview of some of the main physical factors known to cause variation in the vegetation on serpentine both at the regional and local levels. Finally, we discuss what is known about the roles of competition, fire, herbivory, and other ecological processes in shaping plant assemblages on serpentine. The availability of botanical information varies considerably around the world. In most countries where serpentine occurs, it is possible to name at least some of the plant species and vegetation types found on it. But in countries where surveys are incomplete, or where information has not been synthesized at a national or larger level, it is generally not possible to estimate the number of serpentine-endemic taxa or to describe patterns of variation within the serpentine vegetation. Indonesia, Malaysia, the Phillippines, and Brazil are particularly notable as countries with serpentine floras that are potentially rich but in need of more study. With this caveat, however, some of the major global trends can be described based on available knowledge. Flora and vegetation of selected parts of the world are summarized in table 10-1, and global contrasts between the vegetation of serpentine and other soils are summarized in table 10-2. New Caledonia and Cuba lead the world in known serpentine endemic diversity with 900+ species each, >90% of which are also endemics to these islands. Depending on elevation, rainfall, and fire history, the serpentine vegetation on both islands varies from sclerophyllous scrubland that contrasts visibly with the neighboring vegetation, to medium-stature rainforest that is not strikingly different in appearance from the vegetation growing in other soils.

scholarly journals Contrasting Performance of the Remotely-Derived GPP Products over Different Climate Zones across China

2019 ◽  
Vol 11 (16) ◽  
pp. 1855 ◽  
Author(s):  
Yanan Chen ◽  
Hongfan Gu ◽  
Munan Wang ◽  
Qing Gu ◽  
Zhi Ding ◽  
...  
Keyword(s):  
Large Scale ◽  
Climatic Factors ◽  
Southern China ◽  
Gross Primary Production ◽  
Terrestrial Ecosystems ◽  
Northern China ◽  
Tibet Plateau ◽  
Semiarid Region ◽  
Interannual Variations ◽  
Climate Zones

Precise quantification of terrestrial gross primary production (GPP) has been recognized as one of the most important components in understanding the carbon balance between the biosphere and the atmosphere. In recent years, although many large-scale GPP estimates from satellite data and ecosystem models have been generated, few attempts have been made to compare the different GPP products at national scales, particularly for various climate zones. In this study, two of the most widely-used GPP datasets were systematically compared over the eight climate zones across China’s terrestrial ecosystems from 2001 to 2015, which included the moderate resolution imaging spectroradiometer (MODIS) GPP and the breathing Earth system simulator (BESS) GPP products. Additionally, the coarse (0.05o) GPP estimates from the vegetation photosynthesis model (VPM) at the same time scale were used for auxiliary analysis with the two products. Both MODIS and BESS products exhibited a decreasing trend from the southeast region to the northwest inland. The largest GPP was found in the tropical humid region with 5.49 g C m−2 d−1 and 5.07 g C m−2 d−1 for MODIS and BESS, respectively, while the lowest GPP was distributed in the warm temperate arid region, midtemperate semiarid region and plateau zone. Meanwhile, the work confirmed that all these GPP products showed apparent seasonality with the peaks in the summertime. However, large differences were found in the interannual variations across the three GPP products over different climate regions. Generally, the BESS GPP agreed better than the MODIS GPP when compared to the seasonal and interannual variations of VPM GPP. Furthermore, the spatial correlation analysis between terrestrial GPP and the climatic factors, including temperature and precipitation, indicated that natural rainfall dominated the variability in GPP of Northern China, such as the midtemperate semiarid region, while temperature was a key controlling factor in the Southern China and the Tibet Plateau area.

scholarly journals Feasibility of Using MODIS Products to Simulate Sun-Induced Chlorophyll Fluorescence (SIF) in Boreal Forests

2020 ◽  
Vol 12 (4) ◽  
pp. 680 ◽  
Author(s):  
Meng Guo ◽  
Jing Li ◽  
Shubo Huang ◽  
Lixiang Wen
Keyword(s):  
Chlorophyll Fluorescence ◽  
Boreal Forest ◽  
Spatial Resolution ◽  
Vegetation Index ◽  
Mean Squared Error ◽  
Gross Primary Production ◽  
Coniferous Forest ◽  
Terrestrial Ecosystems ◽  
Linear Regression Models ◽  
Modis Evi

Solar-induced chlorophyll fluorescence (SIF) is a novel approach to gain information about plant activity from remote sensing observations. However, there are currently no continuous SIF data produced at high spatial resolutions. Many previous studies have discussed the relationship between SIF and gross primary production (GPP) and showed a significant correlation between them, but few researchers have focused on forests, which are one the most important terrestrial ecosystems. This study takes Greater Khingan Mountains, a typical boreal forest in China, as an example to explore the feasibility of using MODerate resolution Imaging Spectroradiometer (MODIS) products and Orbiting Carbon Observatory-2 (OCO-2) SIF data to simulate continuous SIF at higher spatial resolutions. The results show that there is no significant correlation between SIF and MODIS GPP at a spatial resolution of 1 km; however, significant correlations between SIF and the enhanced vegetation index (EVI) were found during growing seasons. Furthermore, the broadleaf forest has a higher SIF than coniferous forest because of the difference in leaf and canopy bio-chemical and structural characteristic. When using MODIS EVI to model SIF, linear regression models show average performance (R2 = 0.58, Root Mean Squared Error (RMSE) = 0.14 from Julian day 145 to 257) at a 16-day time scale. However, when using MODIS EVI and temperature, multiple regressions perform better (R2 = 0.71, RMSE = 0.13 from Julian day 145 to 241). An important contribution of this paper is the analysis of the relationships between SIF and vegetation indices at different spatial resolutions and the finding that the relationships became closer with a decrease in spatial resolution. From this research, we conclude that the SIF of the boreal forest investigated can mainly be explained by EVI and air temperature.

Interaction of epithelium with mesenchyme affects global features of lung architecture: a computer model of development

2007 ◽  
Vol 102 (1) ◽  
pp. 294-305 ◽  
Author(s):  
Seth Tebockhorst ◽  
DongYoub Lee ◽  
Anthony S. Wexler ◽  
Michael J. Oldham
Keyword(s):  
Local Development ◽  
Critical Role ◽  
Branching Morphogenesis ◽  
Global Features ◽  
Local Branching ◽  
Morphogen Gradients ◽  
Simple Rules ◽  
Global Patterns ◽  
Architecture Development

Lung airway morphogenesis is simulated in a simplified diffusing environment that simulates the mesenchyme to explore the role of morphogens in airway architecture development. Simple rules govern local branching morphogenesis. Morphogen gradients are modeled by four pairs of sources and their diffusion through the mesenchyme. Sensitivity to lobar architecture and mesenchymal morphogen are explored. Even if the model accurately represents observed patterns of local development, it could not produce realistic global patterns of lung architecture if interaction with its environment was not taken into account, implying that reciprocal interaction between airway growth and morphogens in the mesenchyme plays a critical role in producing realistic global features of lung architecture.

scholarly journals Environmental Filtering Drives the Assembly of Habitat Generalists and Specialists in the Coastal Sand Microbial Communities of Southern China

2019 ◽  
Vol 7 (12) ◽  
pp. 598 ◽  
Author(s):  
Anyi Hu ◽  
Hongjie Wang ◽  
Meixian Cao ◽  
Azhar Rashid ◽  
Mingfeng Li ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Southern China ◽  
Critical Role ◽  
Environmental Filtering ◽  
Amplicon Sequencing ◽  
Neutral Model ◽  
Ecological Processes ◽  
Opposite Pattern ◽  
Coastal Sand ◽  
Habitat Generalists

Coastal sands harbor diverse microbial assemblages that play a critical role in the biogeochemical cycling of beach ecosystems. However, little is known about the relative importance of the different ecological processes underlying the assembly of communities of sand microbiota. Here, we employed 16S rDNA amplicon sequencing to investigate the sand microbiota of two coastal beaches, in southern China. The results showed that sand microbial assemblages at intertidal and supratidal zones exhibited contrasting compositions that can be attributed to environmental filtering by electric conductivity. A consistent pattern of habitat generalists and specialists of sand microbiota was observed among different beach zones. Null and neutral model analyses indicated that the environmental filtering was mainly responsible for supratidal microbial communities, while the neutral processes could partially influence the assembly of intertidal communities. Moreover, environmental filtering was found to shape the habitat specialists, while random dispersal played a major role in shaping generalists. The neutral model analysis revealed that the habitat generalists exceeding the neutral prediction harbored a relatively higher proportion of microbial taxa than the specialist counterparts. An opposite pattern was observed for taxa falling below the neutral prediction. Collectively, these findings offer a novel insight into the assembly mechanisms of coastal sand microbiota.

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