scholarly journals Impact of CO<sub>2</sub> and climate on Last Glacial Maximum vegetation – a factor separation

2012 ◽  
Vol 9 (11) ◽  
pp. 15823-15852
Author(s):  
M. Claussen ◽  
K. Selent ◽  
V. Brovkin ◽  
T. Raddatz ◽  
V. Gayler
Keyword(s):  
Tropical Forests ◽  
Climate Warming ◽  
Net Primary Production ◽  
Plant Functional Types ◽  
Strong Increase ◽  
Vegetation Patterns ◽  
Climate Effect ◽  
Fractional Coverage ◽  
Functional Types ◽  
Factor Separation

Abstract. Differences between glacial and pre-industrial potential vegetation patterns can conceptually be attributed to two factors: firstly to differences in the climate, caused by a strong increase in ice masses and the radiative effect of lower greenhouse gas concentrations, and secondly to differences in the ecophysiological effect of lower glacial atmospheric CO2 concentrations. The synergy emerging from these effects when operating simultaneously can be interpreted as sensitivity of the effect of enhancing physiologically available CO2 on shifting vegetation to climate warming. Alternatively and equally valid, it can be viewed as sensitivity of climatically induced vegetation changes to differences in physiologically available CO2. A first complete factor separation based on simulations with the MPI Earth System Model indicates that the pure climate effect mainly leads to a contraction or a shift in vegetation patterns when comparing glacial with pre-industrial simulation vegetation patterns. Globally, a reduction in fractional coverage of most plant functional types is seen – except for raingreen shrubs which strongly benefit from the colder and drier climate. The ecophysiological effect of CO2 appears to be stronger than the pure climate contribution for many plant functional types – in line with previous simulations. The ecophysiological effect of lower CO2 mainly yields a reduction in fractional coverage, a thinning of vegetation and a strong reduction in net primary production. The synergy appears to be as strong as each of the pure contributions locally. For tropical evergreen trees, the synergy appears strong also on global average. Hence this modelling study suggests that for tropical forests, an increase in CO2 has, on average, a stronger ecophysiological effect in warmer climate than in glacial climate. Alternatively, areal differences in tropical forests induced by climate warming can, on average, be expected to be larger with increasing concentration of physiologically effective CO2.

scholarly journals Impact of CO<sub>2</sub> and climate on Last Glacial maximum vegetation – a factor separation

2013 ◽  
Vol 10 (6) ◽  
pp. 3593-3604 ◽  
Author(s):  
M. Claussen ◽  
K. Selent ◽  
V. Brovkin ◽  
T. Raddatz ◽  
V. Gayler
Keyword(s):  
Net Primary Production ◽  
Plant Functional Types ◽  
Strong Increase ◽  
Vegetation Patterns ◽  
Climate Effect ◽  
Global Average ◽  
Functional Types ◽  
The Difference ◽  
Atmospheric Co2 Concentrations ◽  
Factor Separation

Abstract. The factor separation of Stein and Alpert (1993) is applied to simulations with the MPI Earth system model to determine the factors which cause the differences between vegetation patterns in glacial and pre-industrial climate. The factors firstly include differences in the climate, caused by a strong increase in ice masses and the radiative effect of lower greenhouse gas concentrations; secondly, differences in the ecophysiological effect of lower glacial atmospheric CO2 concentrations; and thirdly, the synergy between the pure climate effect and the pure effect of changing physiologically available CO2. It is has been shown that the synergy can be interpreted as a measure of the sensitivity of ecophysiological CO2 effect to climate. The pure climate effect mainly leads to a contraction or a shift in vegetation patterns when comparing simulated glacial and pre-industrial vegetation patterns. Raingreen shrubs benefit from the colder and drier climate. The pure ecophysiological effect of CO2 appears to be stronger than the pure climate effect for many plant functional types – in line with previous simulations. The pure ecophysiological effect of lower CO2 mainly yields a reduction in fractional coverage, a thinning of vegetation and a strong reduction in net primary production. The synergy appears to be as strong as each of the pure contributions locally, but weak on global average for most plant functional types. For tropical evergreen trees, however, the synergy is strong on global average. It diminishes the difference between glacial and pre-industrial coverage of tropical evergreen trees, due to the pure climate effect and the pure ecophysiological CO2 effect, by approximately 50 per cent.

scholarly journals Competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

2016 ◽  
Vol 9 (1) ◽  
pp. 323-361 ◽  
Author(s):  
J. R. Melton ◽  
V. K. Arora
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Plant Functional Types ◽  
Atmospheric Composition ◽  
Climate Modelling ◽  
Fractional Coverage ◽  
Terrestrial Ecosystem Model ◽  
Functional Types

Abstract. The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the Earth system model of the Canadian Centre for Climate Modelling and Analysis. CTEM models land–atmosphere exchange of CO2 through the response of carbon in living vegetation, and dead litter and soil pools, to changes in weather and climate at timescales of days to centuries. Version 1.0 of CTEM uses prescribed fractional coverage of plant functional types (PFTs) although, in reality, vegetation cover continually adapts to changes in climate, atmospheric composition and anthropogenic forcing. Changes in the spatial distribution of vegetation occur on timescales of years to centuries as vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM, which includes a representation of competition between PFTs based on a modified version of the Lotka–Volterra (L–V) predator–prey equations. Our approach is used to dynamically simulate the fractional coverage of CTEM's seven natural, non-crop PFTs, which are then compared with available observation-based estimates. Results from CTEM v. 2.0 show the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. However, differences remain between modelled and observation-based fractional coverage of PFTs since representing the multitude of plant species globally, with just seven non-crop PFTs, only captures the large-scale climatic controls on PFT distributions. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model, and the corresponding driving climate, or the limited number of PFTs used. We also simulate the fractional coverage of PFTs using unmodified L–V equations to illustrate its limitations. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably well with each other and observation-based estimates. The parametrization of competition between PFTs in CTEM v. 2.0 based on the modified L–V equations behaves in a reasonably realistic manner and yields a tool with which to investigate the changes in spatial distribution of vegetation in response to future changes in climate.

scholarly journals Consequences of a Reduced Number of Plant Functional Types for the Simulation of Forest Productivity

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 460 ◽  
Author(s):  
Rico Fischer ◽  
Edna Rödig ◽  
Andreas Huth
Keyword(s):  
Tropical Forests ◽  
Tree Species ◽  
Forest Succession ◽  
Carbon Fluxes ◽  
Forest Growth ◽  
Plant Functional Types ◽  
Pioneer Tree Species ◽  
Old Growth Forest ◽  
Pioneer Tree ◽  
Functional Types

Tropical forests represent an important pool in the global carbon cycle. Their biomass stocks and carbon fluxes are variable in space and time, which is a challenge for accurate measurements. Forest models are therefore used to investigate these complex forest dynamics. The challenge of considering the high species diversity of tropical forests is often addressed by grouping species into plant functional types (PFTs). We investigated how reduced numbers of PFTs affect the prediction of productivity (GPP, NPP) and other carbon fluxes derived from forest simulations. We therefore parameterized a forest gap model for a specific study site with just one PFT (comparable to global vegetation models) on the one hand, and two versions with a higher amount of PFTs, on the other hand. For an old-growth forest, aboveground biomass and basal area can be reproduced very well with all parameterizations. However, the absence of pioneer tree species in the parameterizations with just one PFT leads to a reduction in estimated gross primary production by 60% and an increase of estimated net ecosystem exchange by 50%. These findings may have consequences for productivity estimates of forests at regional and continental scales. Models with a reduced number of PFTs are limited in simulating forest succession, in particular regarding the forest growth after disturbances or transient dynamics. We conclude that a higher amount of species groups increases the accuracy of forest succession simulations. We suggest using at a minimum three PFTs with at least one species group representing pioneer tree species.

Assessing the response of plant functional types to climatic change in tropical forests

1996 ◽  
Vol 7 (3) ◽  
pp. 405-416 ◽  
Author(s):  
Richard Condit ◽  
Stephen P. Hubbell ◽  
Robin B. Foster
Keyword(s):  
Climatic Change ◽  
Tropical Forests ◽  
Plant Functional Types ◽  
Functional Types

scholarly journals Plant-driven variation in decomposition rates improves projections of global litter stock distribution

2011 ◽  
Vol 8 (4) ◽  
pp. 8817-8844 ◽  
Author(s):  
V. Brovkin ◽  
P. M. van Bodegom ◽  
T. Kleinen ◽  
C. Wirth ◽  
W. Cornwell ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Boreal Forests ◽  
Fire Regimes ◽  
Plant Litter ◽  
Plant Functional Types ◽  
Atmospheric Co2 ◽  
Strong Increase ◽  
Decomposition Rates ◽  
Global Databases ◽  
Functional Types

Abstract. Plant litter stocks are critical, regionally for their role in fueling fire regimes and controlling soil fertility, and globally through their feedback to atmospheric CO2 and climate. Here we employ two global databases linking plant functional types to decomposition rates of wood and leaf litter (Cornwell et al., 2008; Weedon et al., 2009) to improve future projections of climate and carbon cycle using an intermediate complexity Earth system model. Implementing separate wood and leaf litter decomposabilities and their temperature sensitivities for a range of plant functional types yielded a more realistic distribution of litter stocks in all present biomes with except of boreal forests and projects a strong increase in global litter stocks and a concomitant small decrease in atmospheric CO2 by the end of this century. Despite a relatively strong increase in litter stocks, the modified parameterization results in less elevated wildfire emissions because of litter redistribution towards more humid regions.

scholarly journals An assessment of geographical distribution of different plant functional types over North America simulated using the CLASS–CTEM modelling framework

2017 ◽  
Vol 14 (20) ◽  
pp. 4733-4753 ◽  
Author(s):  
Rudra K. Shrestha ◽  
Vivek K. Arora ◽  
Joe R. Melton ◽  
Laxmi Sushama
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Plant Functional Types ◽  
The Arctic ◽  
Vegetation Coverage ◽  
Fractional Coverage ◽  
Terrestrial Ecosystem Model ◽  
Modelling Framework ◽  
Functional Types ◽  
Vegetation Fractional Coverage

Abstract. The performance of the competition module of the CLASS–CTEM (Canadian Land Surface Scheme and Canadian Terrestrial Ecosystem Model) modelling framework is assessed at 1° spatial resolution over North America by comparing the simulated geographical distribution of its plant functional types (PFTs) with two observation-based estimates. The model successfully reproduces the broad geographical distribution of trees, grasses and bare ground although limitations remain. In particular, compared to the two observation-based estimates, the simulated fractional vegetation coverage is lower in the arid southwest North American region and higher in the Arctic region. The lower-than-observed simulated vegetation coverage in the southwest region is attributed to lack of representation of shrubs in the model and plausible errors in the observation-based data sets. The observation-based data indicate vegetation fractional coverage of more than 60 % in this arid region, despite only 200–300 mm of precipitation that the region receives annually, and observation-based leaf area index (LAI) values in the region are lower than one. The higher-than-observed vegetation fractional coverage in the Arctic is likely due to the lack of representation of moss and lichen PFTs and also likely because of inadequate representation of permafrost in the model as a result of which the C3 grass PFT performs overly well in the region. The model generally reproduces the broad spatial distribution and the total area covered by the two primary tree PFTs (needleleaf evergreen trees, NDL-EVG; and broadleaf cold deciduous trees, BDL-DCD-CLD) reasonably well. The simulated fractional coverage of tree PFTs increases after the 1960s in response to the CO2 fertilization effect and climate warming. Differences between observed and simulated PFT coverages highlight model limitations and suggest that the inclusion of shrubs, and moss and lichen PFTs, and an adequate representation of permafrost will help improve model performance.

scholarly journals Plant functional types and traits as biodiversity indicators for tropical forests: two biogeographically separated case studies including birds, mammals and termites

2013 ◽  
Vol 22 (9) ◽  
pp. 1909-1930 ◽  
Author(s):  
Andrew N. Gillison ◽  
David E. Bignell ◽  
Kenneth R. W. Brewer ◽  
Erick C. M. Fernandes ◽  
David T. Jones ◽  
...  
Keyword(s):  
Case Studies ◽  
Tropical Forests ◽  
Plant Functional Types ◽  
Biodiversity Indicators ◽  
Functional Types

scholarly journals An assessment of geographical distribution of different plant functional types over North America simulated using the CLASS-CTEM modelling framework

2017 ◽  
Author(s):  
Rudra K. Shrestha ◽  
Vivek K. Arora ◽  
Joe R. Melton ◽  
Laxmi Sushama
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Plant Functional Types ◽  
The Arctic ◽  
Vegetation Coverage ◽  
Fractional Coverage ◽  
Modelling Framework ◽  
South West ◽  
Functional Types ◽  
Vegetation Fractional Coverage

Abstract. The performance of the competition module of the CLASS-CTEM (Canadian Land Surface Scheme and Canadian Terrestrial Ecosystem Model) modelling framework is assessed at 1° spatial resolution over North America by comparing the simulated geographical distribution of plant functional types (PFTs) with two observation-based estimates. The model successfully reproduces the broad geographical distribution of trees, grasses and bare ground although limitations remain. In particular, compared to the two observation-based estimates, the simulated fractional vegetation coverage is lower in the arid south-west North American region and higher in the Arctic region. The lower than observed simulated vegetation coverage in the south-west region is attributed to lack of representation of shrubs in the model and plausible errors in the observation-based data sets. The observation-based data indicates vegetation fractional coverage of more than 60 % in this arid region, despite only 200–300 mm of precipitation that the region receives annually and observation-based leaf area index (LAI) in the region are lower than one. The higher than observed vegetation fractional coverage in the Arctic is due to the lack of representation of moss and lichen PFTs and also likely because of inadequate representation of permafrost in the model as a result of which the C3 grass PFT performs overly well in the region. The model generally reproduces the broad spatial distribution and the total area covered by the two primary tree PFTs (needleleaf evergreen and broadleaf cold deciduous trees) reasonably well. The simulated fractional coverage of tree PFTs increases after 1960s in response to the CO2 fertilization effect and climate warming. Differences between observed and simulated PFT coverages highlight limitations in the model and provide insight into physical and structural processes that need improvement.

scholarly journals Holocene vegetation transitions and their climatic drivers in MPI-ESM1.2

2021 ◽  
Author(s):  
Anne Dallmeyer ◽  
Martin Claussen ◽  
Stephan J. Lorenz ◽  
Michael Sigl ◽  
Matthew Toohey ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Large Scale ◽  
Vegetation Change ◽  
Net Primary Production ◽  
Plant Functional Types ◽  
Holocene Climate ◽  
The Holocene ◽  
Functional Types ◽  
Northern Latitudes ◽  
Rapid Changes

Abstract. We present a transient simulation of global vegetation and climate patterns of the mid and late Holocene using the MPI-ESM (Max Planck Institute for Meteorology Earth System Model) at T63 resolution. The simulated vegetation trend is discussed in the context of the simulated Holocene climate change. Our model captures the main trends found in reconstructions. Most prominent are the southward retreat of the northern treeline that is combined with the strong decrease of forest in the high northern latitudes during the Holocene and the vast increase of the Saharan desert, embedded in a general decrease in precipitation and vegetation in the northern hemispheric monsoon margin regions. The southern hemisphere experiences weaker changes in total vegetation cover during the last 8000 years. However, the monsoon-related increase in precipitation and the insolation-induced cooling of the winter climate lead to shifts in the vegetation composition, mainly between the woody plant functional types (PFTs). The large-scale global patterns of vegetation almost linearly follow the subtle, approximately linear, orbital forcing. In some regions, however, non-linear, more rapid changes in vegetation are found in the simulation. The most striking region is the Sahel-Sahara domain with rapid vegetation transitions to a rather desertic state, despite a gradual insolation forcing. Rapid shifts in the simulated vegetation also occur in the high northern latitudes, in South Asia and in the monsoon margins of the southern hemisphere. These rapid changes are mainly triggered by changes in the winter temperatures, which go into, or move out of, the bioclimatic tolerance range of individual PFTs (Plant Functional Types). The dynamics of the transitions are determined by dynamics of the Net Primary Production (NPP) and the competition between PFTs. These changes mainly occur on timescales of centuries. More rapid changes in PFTs that occur within a few decades are mainly associated with the time scales of mortality and the bioclimatic thresholds implicit in the dynamic vegetation model, which have to be interpreted with caution. Most of the simulated Holocene vegetation changes outside the high northern latitudes are associated with modifications in the intensity of the global summer monsoon dynamics that also affect the circulation in the extra tropics via teleconnections. Based on our simulations, we thus identify the global monsoons as the key player in the Holocene climate and vegetation change.

scholarly journals Competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

2015 ◽  
Vol 8 (6) ◽  
pp. 4851-4948 ◽  
Author(s):  
J. R. Melton ◽  
V. K. Arora
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Plant Functional Types ◽  
Atmospheric Composition ◽  
Climate Modelling ◽  
Fractional Coverage ◽  
Terrestrial Ecosystem Model ◽  
Functional Types

Abstract. The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the Earth system model of the Canadian Centre for Climate Modelling and Analysis. CTEM models land–atmosphere exchange of CO2 through the response of carbon in living vegetation, and dead litter and soil pools, to changes in weather and climate at timescales of days to centuries. Version 1.0 of CTEM uses prescribed fractional coverage of plant functional types (PFTs) although, in reality, vegetation cover continually adapts to changes in climate, atmospheric composition, and anthropogenic forcing. Changes in the spatial distribution of vegetation occur on timescales of years to centuries as vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM which includes a representation of competition between PFTs based on a modified version of the Lotka–Volterra (L–V) predator–prey equations. Our approach is used to dynamically simulate the fractional coverage of CTEM's seven natural, non-crop PFTs which are then compared with available observation-based estimates. Results from CTEM v. 2.0 show the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. However, differences remain between modelled and observation-based fractional coverages of PFTs since representing the multitude of plant species globally, with just seven non-crop PFTs, only captures the large scale climatic controls on PFT distributions. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model, and the corresponding driving climate, or the limited number of PFTs used. We also simulate the fractional coverages of PFTs using unmodified L–V equations to illustrate its limitations. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably well with each other and observation-based estimates. The parametrization of competition between PFTs in CTEM v. 2.0 based on the modified L–V equations behaves in a reasonably realistic manner and yields a tool with which to investigate the changes in spatial distribution of vegetation in response to future changes in climate.

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