TY  - JOUR
A1  - Wang, Ming
A1  - White, Neil
A1  - Grimm, Volker
A1  - Hofman, Helen
A1  - Doley, David
A1  - Thorp, Grant
A1  - Cribb, Bronwen
A1  - Wherritt, Ella
A1  - Han, Liqi
A1  - Wilkie, John
A1  - Hanan, Jim
T1  - Pattern-oriented modelling as a novel way to verify and validate functional-structural plant models
BT  - a demonstration with the annual growth module of avocado
JF  - Annals of botany
N2  - Background and Aims Functional-structural plant (FSP) models have been widely used to understand the complex interactions between plant architecture and underlying developmental mechanisms. However, to obtain evidence that a model captures these mechanisms correctly, a clear distinction must be made between model outputs used for calibration and thus verification, and outputs used for validation. In pattern-oriented modelling (POM), multiple verification patterns are used as filters for rejecting unrealistic model structures and parameter combinations, while a second, independent set of patterns is used for validation. Key Results After calibration, our model simultaneously reproduced multiple observed architectural patterns. The model then successfully predicted, without further calibration, the validation patterns. The model supports the hypothesis that carbon allocation can be modelled as being dependent on current organ biomass and sink strength of each organ type, and also predicted the observed developmental timing of the leaf sink-source transition stage.
KW  - Pattern-oriented modelling
KW  - agent-based model
KW  - individual-based model
KW  - functional-structural plant model
KW  - model analysis
KW  - model verification
KW  - model validation
KW  - ODD (Overview, Design concepts, Details) protocol
KW  - Persea americana
KW  - plant architecture
KW  - carbon allocation
KW  - L-systems
Y1  - 2018
U6  - https://doi.org/10.1093/aob/mcx187
SN  - 0305-7364
SN  - 1095-8290
VL  - 121
IS  - 5
SP  - 941
EP  - 959
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Crawford, Michael
A1  - Jeltsch, Florian
A1  - May, Felix
A1  - Grimm, Volker
A1  - Schlägel, Ulrike E.
T1  - Intraspecific trait variation increases species diversity in a trait-based grassland model
JF  - Oikos
N2  - Intraspecific trait variation (ITV) is thought to play a significant role in community assembly, but the magnitude and direction of its influence are not well understood. Although it may be critical to better explain population persistence, species interactions, and therefore biodiversity patterns, manipulating ITV in experiments is challenging. We therefore incorporated ITV into a trait‐ and individual‐based model of grassland community assembly by adding variation to the plants’ functional traits, which then drive life‐history tradeoffs. Varying the amount of ITV in the simulation, we examine its influence on pairwise‐coexistence and then on the species diversity in communities of different initial sizes. We find that ITV increases the ability of the weakest species to invade most, but that this effect does not scale to the community level, where the primary effect of ITV is to increase the persistence and abundance of the competitively‐average species. Diversity of the initial community is also of critical importance in determining ITV's efficacy; above a threshold of interspecific diversity, ITV does not increase diversity further. For communities below this threshold, ITV mainly helps to increase diversity in those communities that would otherwise be low‐diversity. These findings suggest that ITV actively maintains diversity by helping the species on the margins of persistence, but mostly in habitats of relatively low alpha and beta diversity.
KW  - community assembly
KW  - individual-based model
KW  - intraspecific trait variation
Y1  - 2018
U6  - https://doi.org/10.1111/oik.05567
SN  - 0030-1299
SN  - 1600-0706
VL  - 128
IS  - 3
SP  - 441
EP  - 455
PB  - Wiley
CY  - Hoboken
ER  -