Representation of vegetation dynamics in the modelling of terrestrial ecosystems: comparing two contrasting approaches within European climate space

1 Advances in dynamic ecosystem modelling have made a number of different approaches to vegetation dynamics possible. Here we compare two models representing contrasting degrees of abstraction of the processes governing dynamics in real vegetation. 2 Model (a) (GUESS) simulates explicitly growth and competition among individual plants. Differences in crown structure (height, depth, area and LAI) influence relative light uptake by neighbours. Assimilated carbon is allocated individually by each plant to its leaf, fine root and sapwood tissues. Carbon allocation and turnover of sapwood to heartwood in turn govern height and diameter growth. 3 Model (b) (LPJ) incorporates a ‘dynamic global vegetation model’ (DGVM) architecture, simulating growth of populations of plant functional types (PFTs) over a grid cell, integrating individual-level processes over the proportional area (foliar projective cover, FPC) occupied by each PFT. Individual plants are not simulated, but are replaced by explicit parameterizations of their growth and interactions. 4 The models are identical in their representation of core physiological and biogeochemical processes. Both also use the same set of PFTs, corresponding to the major woody plant groups in Europe, plus a grass type. 5 When applied at a range of locations, broadly spanning climatic variation within Europe, both models successfully predicted PFT composition and succession within modern natural vegetation. However, the individual-based model performed better in areas where deciduous and evergreen types coincide, and in areas subject to pronounced seasonal water deficits, which would tend to favour grasses over drought-intolerant trees. 6 Differences in model performance could be traced to their treatment of individual-level processes, in particular light competition and stress-induced mortality. 7 Our results suggest that an explicit individual-based approach to vegetation dynamics may be an advantage in modelling of ecosystem structure and function at the resolution required for regional- to continental-scale studies.

[1]  J. Slavíková.  Vegetation of the earth and ecological systems of the geo-biosphere , 1981, Biologia Plantarum.

[2]  Michael T. Coe,et al.  Testing the performance of a dynamic global ecosystem model: Water balance, carbon balance, and vegetation structure , 2000 .

[3]  Douglas P. Wiens,et al.  Comparison of nonlinear height–diameter functions for major Alberta tree species , 1992 .

[4]  I. C. Prentice,et al.  An integrated biosphere model of land surface processes , 1996 .

[5]  I. Colin Prentice,et al.  Silvics of north European trees: compilation, comparisons and implications for forest succession modelling. , 1991 .

[6]  S. Pacala,et al.  Forest models defined by field measurements : Estimation, error analysis and dynamics , 1996 .

[7]  Hsin-I Wu,et al.  Spatial considerations in physiological models of tree growth. , 1986, Tree physiology.

[8]  T. Czárán,et al.  The effect of spatial pattern on community dynamics; a comparison of simulated and field data , 1989, Vegetatio.

[9]  T. Kira,et al.  A QUANTITATIVE ANALYSIS OF PLANT FORM-THE PIPE MODEL THEORY : I.BASIC ANALYSES , 1964 .

[10]  M. G. Ryan,et al.  Respiration from the organ level to the stand , 1995 .

[11]  M. G. Ryan,et al.  Effects of Climate Change on Plant Respiration. , 1991, Ecological applications : a publication of the Ecological Society of America.

[12]  Jean Clobert,et al.  Tree community dynamics in a humid savanna of the Côte-d'Ivoire: modelling the effects of fire and competition with grass and neighbours. , 1990 .

[13]  Boris Zeide,et al.  Primary Unit of the Tree Crown , 1993 .

[14]  S. Sitch.  The role of vegetation dynamics in the control of atmospheric CO2 content , 2000 .

[15]  M. Fortescue.  Pattern and Process: A Whiteheadian perspective on linguistics , 2001 .

[16]  J. Lloyd,et al.  On the temperature dependence of soil respiration , 1994 .

[17]  M. Monsi.  Uber den Lichtfaktor in den Pflanzengesellschaften und seine Bedeutung fur die Stoffproduktion , 1953 .

[18]  S. Pacala,et al.  Forest models defined by field measurements: I. The design of a northeastern forest simulator , 1993 .

[19]  Wolfgang Cramer,et al.  A simulation model for the transient effects of climate change on forest landscapes , 1993 .

[20]  I. C. Prentice,et al.  BIOME3: An equilibrium terrestrial biosphere model based on ecophysiological constraints, resource availability, and competition among plant functional types , 1996 .

[21]  Mark R. Fulton,et al.  Adult recruitment as a function of juvenile growth rate in size- structured plant populations , 1991 .

[22]  Douglas H. Deutschman,et al.  Details That Matter: The Spatial Distribution of Individual Trees Maintains Forest Ecosystem Function , 1995 .

[23]  Wolfgang Cramer,et al.  An introduction to the European Terrestrial Ecosystem Modelling Activity , 2008 .

[24]  Wolfgang Cramer,et al.  The effects of fragmentation and disturbance of rainforest on ground‐dwelling small mammals on the Robertson Plateau, New South Wales, Australia , 1996, Journal of Biogeography.

[25]  Tonya D. Horton.  An Introduction to the Euro , 1999 .

[26]  Joe Landsberg,et al.  Physiological ecology of forest production , 1986 .

[27]  R. Busing,et al.  A spatial model of forest dynamics , 1991, Vegetatio.

[28]  John L. Harper,et al.  Population Biology of Plants. , 1978 .

[29]  N. Kräuchi.  Modelling forest succession as influenced by a changing environment , 1994 .

[30]  o. Prof. em. Dr. h. c. Heinrich Walter,et al.  Vegetation of the Earth and Ecological Systems of the Geobiosphere , 1983, Heidelberg Science Library.

[31]  J. B. Faliński.  Vegetation Dynamics in Temperate Lowland Primeval Forests , 1986, Geobotany.

[32]  Ian D. Davies,et al.  A spatial model of savanna function and dynamics: model description and preliminary results. , 1998 .

[33]  P. Reich,et al.  Leaf Life‐Span in Relation to Leaf, Plant, and Stand Characteristics among Diverse Ecosystems , 1992 .

[34]  R. Leemans,et al.  Pattern and process and the dynamics of forest structure: a simulation approach. , 1990 .

[35]  Hervé Sinoquet,et al.  Treegrass: a 3D, process-based model for simulating plant interactions in tree-grass ecosystems , 2000 .

[36]  Stephen P. Ellner,et al.  Coexistence of plant species with similar niches , 1984, Vegetatio.

[37]  F. Woodward,et al.  Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models , 2001 .

[38]  L. Aarssen.  Causes and consequences of variation in competitive ability in plant communities , 1992 .