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

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.

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

10.5194/bg-2017-35 ◽

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.

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

Geoscientific Model Development ◽

10.5194/gmd-9-323-2016 ◽

2016 ◽

Vol 9 (1) ◽

pp. 323-361 ◽

Cited By ~ 52

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.

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

Geoscientific Model Development Discussions ◽

10.5194/gmdd-8-4851-2015 ◽

2015 ◽

Vol 8 (6) ◽

pp. 4851-4948 ◽

Cited By ~ 2

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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Simulating Competition and Coexistence between Plant Functional Types in a Dynamic Vegetation Model

Earth Interactions ◽

10.1175/ei170.1 ◽

2006 ◽

Vol 10 (10) ◽

pp. 1-30 ◽

Cited By ~ 58

Author(s):

Vivek K. Arora ◽

George J. Boer

Keyword(s):

Terrestrial Ecosystem ◽

Ecosystem Model ◽

Plant Functional Types ◽

Quasi Equilibrium ◽

Terrestrial Ecosystem Model ◽

Functional Types ◽

Dynamic Global Vegetation Models ◽

Vegetation Models ◽

Competition Equations ◽

Global Vegetation

Abstract The global distribution of vegetation is broadly determined by climate, and where bioclimatic parameters are favorable for several plant functional types (PFTs), by the competition between them. Most current dynamic global vegetation models (DGVMs) do not, however, explicitly simulate inter-PFT competition and instead determine the existence and fractional coverage of PFTs based on quasi-equilibrium climate–vegetation relationships. When competition is explicitly simulated, versions of Lotka–Volterra (LV) equations developed in the context of interaction between animal species are almost always used. These equations may, however, exhibit unrealistic behavior in some cases and do not, for example, allow the coexistence of different PFTs in equilibrium situations. Coexistence may, however, be obtained by introducing features and mechanisms such as temporal environmental variation and disturbance, among others. A generalized version of the competition equations is proposed that includes the LV equations as a special case, which successfully models competition for a range of climate and vegetation regimes and for which coexistence is a permissible equilibrium solution in the absence of additional mechanisms. The approach is tested for boreal forest, tropical forest, savanna, and temperate forest locations within the framework of the Canadian Terrestrial Ecosystem Model (CTEM) and successfully simulates the observed successional behavior and the observed near-equilibrium distribution of coexisting PFTs.

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Climate change in the Arctic: using plant functional types in a meta-analysis of field experiments

Functional Ecology ◽

10.1046/j.0269-8463.2001.00596.x ◽

2002 ◽

Vol 16 (1) ◽

pp. 4-17 ◽

Cited By ~ 240

Author(s):

C. F. Dormann ◽

S. J. Woodin

Keyword(s):

Climate Change ◽

Field Experiments ◽

Meta Analysis ◽

Plant Functional Types ◽

The Arctic ◽

Functional Types

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The geographical distribution response of plant functional types to climate change in southwestern China

Acta Ecologica Sinica ◽

10.5846/stxb201810302336 ◽

2020 ◽

Vol 40 (1) ◽

Author(s):

陆双飞 LU Shuangfei ◽

殷晓洁 YIN Xiaojie ◽

韦晴雯 WEI Qingwen ◽

张超 ZHANG Chao ◽

马东旭 MA Dongxu ◽

...

Keyword(s):

Climate Change ◽

Geographical Distribution ◽

Plant Functional Types ◽

Southwestern China ◽

Functional Types

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Relative Abundance of Plant Functional Types in Grasslands and Shrublands of North America

Ecological Applications ◽

10.2307/2269602 ◽

1996 ◽

Vol 6 (4) ◽

pp. 1212-1224 ◽

Cited By ~ 203

Author(s):

Jose M. Paruelo ◽

W. K. Lauenroth

Keyword(s):

North America ◽

Relative Abundance ◽

Plant Functional Types ◽

Functional Types

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

Biogeosciences Discussions ◽

10.5194/bgd-9-15823-2012 ◽

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.

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