Co-ordinating Editor: E. Ezcurra.
A functional analysis of large-scale temporal shifts from 1970 to 2000 in weed assemblages of sunflower crops in France
Article first published online: 23 FEB 2009
© 2009 International Association for Vegetation Science
Journal of Vegetation Science
Volume 20, Issue 1, pages 49–58, February 2009
How to Cite
Fried, G., Chauvel, B. and Reboud, X. (2009), A functional analysis of large-scale temporal shifts from 1970 to 2000 in weed assemblages of sunflower crops in France. Journal of Vegetation Science, 20: 49–58. doi: 10.1111/j.1654-1103.2009.05284.x
- Issue published online: 23 FEB 2009
- Article first published online: 23 FEB 2009
- Received 11 April 2007; Accepted 16 January 2008
- Agricultural practice;
- Diachronic survey;
- Helianthus annuus;
- Multiple correspondence analysis;
- Plant functional type;
- Species temporal turnover;
- Trait-based approach;
- Vegetation monitoring
Questions: What are the relationships between weed species traits and their change in distribution over a 30-year period? What does it tell us about factors that have driven shifts in the composition of weed communities?
Methods: We analysed the links between change in the status of weed species in sunflower crops (decreasing or increasing) and a set of 17 traits using data sets collected in the 1970s and the 2000s, respectively. We analysed the contribution of traits to explain changes in the status of species both individually and in a multivariate way by mean of a clustering of species into functional groups.
Results: 69% of the most widespread species had significantly changed their frequency rank status over the last 30 years. Nearly two thirds of the increasing species belonged to a single functional group, out of the five groups identified in this analysis. Overall, the weed flora occurring in sunflower crops has specialised since the 1970s in favour of ‘sunflower mimicking’ functional groups: increasing species were more nitrophilous, more heliophilous, less sensitive to sunflower herbicides and shared a rapid summer life cycle.
Conclusions: The individual trait approach gave some indication as to the environmental factors likely to have caused the shift in sunflower weed communities. The functional group approach seemed to outperform direct trait comparisons as it accounted for major traits combinations i.e. cases where a species has a number of favourable traits, but is severely disadvantaged by the possession of one or a few deleterious traits.