The role of vegetative spread and seed dispersal for optimal life histories of clonal plants: a simulation study
Sexual and vegetative reproduction of clonal plants phenotypically differ in dispersal distance, in the phenology of offspring production and establishment, and in the success of establishment. We applied a combination of analytical and of spatially explicit individual-based simulation modelling to calculate long-term fitness. We predicted optimal clonal plant life histories in a parameter space spanned by stolon number, stolon internode length, and relative allocation to sexual and vegetative reproduction. For a given allocation to sexual reproduction and number of stolons, fitness was optimised for rather short internode lengths under small disturbances, and for the longest possible internodes under larger disturbances. A trade-off between length and number of vegetative spacers drew parameters away from their unrestricted optima. Now, intermediate length and number of spacers led to maximum fitness under large disturbances. Simultaneous trade-offs between sexual and vegetative reproduction and between the length and number of spacers could also lead to fitness optima at intermediate parameter values, depending on the success of seedling establishment. We demonstrated that spatial habitat structure (1) selects for an efficient use of available space either by optimum internode length or by investment into seeds, which disperse farther than vegetative spacers, and (2) leads to an interaction between trade-offs. We conclude, that dispersal distance, i.e. a spatial life-history component, and trade-offs must be included in considerations on adaptive evolution of clonal life histories.
Key wordsclonal plants dispersal disturbed habitat optimal life histories reproduction simulation model trade-off
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- Huston, M., De Angelis, D. and Post, W. (1988) New computer models unify ecological theory. BioScience 38, 682–691.Google Scholar
- Johst, K. and Brandi, R. (1999) Natal versus breeding dispersal: evolution in a model system. Evol. Ecol. Res. 1, 911–921.Google Scholar
- Stearns, S.C. (1992) The Evolution of Life Histories. Oxford University Press, Oxford.Google Scholar
- Watson, A.W., Hay, M.J.M. and Newton, C.D. (1997) Developmental phenology and the timing of determination of shoot bud fates: ways in which the developmental program modulates fitness in clonal plants. In H. de Kroon and J. van Groenendael (eds) The Ecology and Evolution of Clonal Plants. Backhuys Publishers, Leiden, p. 31–53.Google Scholar
- Winkler, E. and Schmid, B. (1995) Clonal strategies of herbaceous plant species: a simulation study on population growth and competition. In B. Oborny and J. Podany (eds) Clonality in Plant Communities. Proceedings of the 4th International Workshop on Clonal Plants (Abstracta Bot. 19, 17–28 ).Google Scholar