Community-level effects of plant traits in a grassland community examined by naultispecies Model of clonal plant growth
Authored by Radka Wildova, Tomas Herben
Date Published: 2012
DOI: 10.1016/j.ecolmodel.2011.06.012
Sponsors:
No sponsors listed
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
Abstract
We examine role of natality-related plant traits in a mountain grassland
community. We use a spatially explicit, individual-based model of clonal
plant population dynamics that includes traits of growth, resource
allocation, response to competition, and spatial spread/plant
architecture, and parameterize it for four co-occurring grass species.
Field measurements of plant growth and architecture were used for
parameterization; the subset of parameters that cannot be obtained by
field estimation were estimated by fitting model predictions to a
fine-scale time series of field data using a formalized gradient-descent
procedure.
The parameterized model was then validated with a separate set of
fine-scale time series of field data. The parameterized model
approximated well grassland dynamics over two decades for which
empirical data were available for comparison. Over long (>50 years)
periods the predictions indicate decrease of spatial correlations and
loss of species richness which does not seem to be realistic in terms of
our knowledge of the modelled grassland systems. This is likely to be
due to structural features of the model, namely equivalence of
competition of ramets that was independent of their tussock or species
identity.
This virtual community was used to test hypotheses on effects of
natality-related traits on community dynamics. We changed values of
individual traits of generative and vegetative reproduction (including
architecture), and examined effects of these changes on (i) performance
of the species with the trait changed, and (ii) performance of
co-occurring species. The analysis showed that effects of individual
traits on its bearer's performance differed across species; the context
of other traits thus interacted with the net trait effect. Comparison of
trait effects in the simulated monoculture with the effect on the whole
community showed that within-community effect of the trait can only be
weakly predicted from its monoculture effect. Individual neighbour
species also differed in their response to a single trait in the target
species. Such modelling approach shows that effects of traits (which
typically cannot be easily manipulated) can be examined both in single
species and in the community. While there was large variation in trait
effects across target and neighbour species, mean effects of individual
traits strongly differed, indicating that traits can be sensibly
generalized over species and constitute a workable reference level for
community studies. (C) 2011 Elsevier By. All rights reserved.
Tags
Simulation
Performance
Diversity
Coexistence
Heterogeneity
scale
Spatial structure
Population-dynamics
Self/non-self discrimination
Competitive ability