Variation in growth pattern and response to slug damage among native and invasive provenances of four perennial Brassicaceae species
Article first published online: 9 MAR 2005
Journal of Ecology
Volume 93, Issue 2, pages 322–334, April 2005
How to Cite
BUSCHMANN, H., EDWARDS, P.J. and DIETZ, H. (2005), Variation in growth pattern and response to slug damage among native and invasive provenances of four perennial Brassicaceae species. Journal of Ecology, 93: 322–334. doi: 10.1111/j.1365-2745.2005.00991.x
- Issue published online: 9 MAR 2005
- Article first published online: 9 MAR 2005
- Received 21 September 2004; revision accepted 13 December Handling Editor: Susan Hartley
- Arion lusitanicus;
- choose experiments;
- clonal growth;
- EICA hypothesis;
- intraspecific comparisons;
- sexual reproduction;
- vegetative reproduction
- 1The EICA (evolution of increased competitive ability) hypothesis suggests that release from natural enemies and pathogens results in higher vigour of invasive plants as a result of the selection of less defended but rapidly growing genotypes. Slug diversity and abundance appear to be low in North America compared with Europe, and we therefore hypothesized that release from slug herbivory contributes to the invasiveness of European Brassicaceae species in North America.
- 2In common garden and glasshouse experiments we compared life history and fitness parameters in native (NP) and introduced (IP) provenances of four invasive Brassicaceae species (Barbarea vulgaris, Bunias orientalis, Cardaria draba, Rorippa austriaca) that were subjected to herbivory by Arion lusitanicus. In climate chamber bioassays we investigated slug damage to seedlings and leaf discs using the same sources of plant material.
- 3In all species except B. orientalis we found significant but not always consistent differences in growth and reproductive characteristics between IP and NP plants. Plants of B. vulgaris and R. austriaca from the introduced range had a considerably higher growth rate than those from the native range. While IP plants of the non-clonal B. vulgaris allocated more resources to seed production than NP plants, the IP plants of the clonal R. austriaca showed a decreased number of seeds.
- 4Contrary to expectation, there were no differences between NP plants and IP plants in the number of damaged leaves and leaf area consumed by slugs, or in the proportion of seedlings damaged and killed. Nor were there interaction effects between slug treatments and provenance.
- 5The results suggest that there are genetically based differences in growth and reproductive parameters between NP and IP plants. As there were no differences in herbivore damage between the provenances, this genetic differentiation is probably due to factors such as competition rather than herbivore effects.
- 6In order to make progress in understanding why some species become invasive, more comparative experimental studies are needed that investigate how different kinds of antagonists (generalist and specialist herbivores and pathogens) influence the performance of plants at different life stages.