Modelling the morphological response to nutrient availability in the clonal plant Trientalis europaea L.

The morphological responses to changes in environmental quality shown by ma ny clonal plants have been interpreted as an expression of foraging behavio ur, as they allow the ramets to become concentrated in more favourable micr ohabitats. The morphological response to increased nutrient availability in the pseudoannual plant Trientalis europaea was studied in a field experime nt. The response was largely size-dependent and consistent with enhanced cl onal growth. Fertilized ramets produced more tubers and a larger main tuber . In contrast, stolon length was not affected by the treatment. A spatially explicit simulation model calibrated with data from the field experiment e xamined the population dynamics of T. europaea ramets in a spatially hetere ogeneous, temporally constant, environment. The model showed that T. europa ea was effective at concentrating its ramets in favourable patches, but thi s process was strongly influenced by patch size. The analysis of this respo nse at the clone level showed that ramet aggregation was mainly due to the enhanced performance of clones located initially in the favourable patches, or clones that located a favourable patch by chance. In these clones, the simultaneous increase of ramet size and survival accelerated the production of ramets. The temporal and spatial scale at which the aggregation of rame ts in favourable patches was manifested suggests that the effectiveness of the morphological response in T. europaea is favoured by a high spatio-temp oral predictability in the environment. Overall, the model emphasized the i mportant role of population dynamics in understanding the nature of the for aging response.