Central and peripheral Hornungia petraea populations: patterns and dynamics
Article first published online: 21 APR 2005
Journal of Ecology
Volume 93, Issue 3, pages 584–595, June 2005
How to Cite
KLUTH, C. and BRUELHEIDE, H. (2005), Central and peripheral Hornungia petraea populations: patterns and dynamics. Journal of Ecology, 93: 584–595. doi: 10.1111/j.1365-2745.2005.00997.x
- Issue published online: 21 APR 2005
- Article first published online: 21 APR 2005
- Received 13 July 2004 revision accepted 22 November 2004 Handling Editor: Michael J. Hutchings
- ‘abundant centre’ distribution;
- central-marginal model;
- evolutionary ecology;
- nested repeated measures design;
- population dynamics;
- spatio-temporal variation
- 1More or less continuous distributions tend to become fragmented towards species’ distribution limits. Peripheral or isolated populations of a species are predicted to have lower population sizes and densities than central populations, as a result of environmental and/or genetic stress. Population densities at the periphery may be reduced by decreased reproduction or higher interannual variation in reproduction. In particular, fecundity and survival are likely to be reduced by less favourable growing conditions.
- 2We compared populations of the annual species Hornungia petraea (Brassicaceae) in two contrasting regions of the species’ range and at the population scale within regions. Ten populations in Italy (central to the species range) and 10 German populations (peripheral) were monitored for three growing periods from spring 1999 to spring 2001.
- 3All life-cycle stages, adult plant density, seed production and pre- and post-dispersal seed bank density were studied in a nested sampling design and variation in various demographic factors was attributed to the effects of the two countries, of populations nested within country and to temporal effects.
- 4Peripheral populations had higher densities than populations in the centre of the species distribution, both as adult plants and in the seed bank.
- 5Fecundity was strongly influenced by temporal effects, but only affected to a minor degree by the study region. High interannual variation in fecundity was not reflected in high interannual variation of either adult plant density in spring or of the seed bank. Significant regional differences were, however, found in seasonal seed bank dynamics, which were more pronounced in peripheral German populations than in central Italian populations.
- 6We conclude that seasonal seed bank dynamics are a key factor in explaining differences in H. petraea density patterns, particularly in central populations, where fewer seeds are incorporated into the seed bank.