Transient facilitative effects of heather on Scots pine along a grazing disturbance gradient in Scottish moorland
Article first published online: 10 APR 2006
Journal of Ecology
Volume 94, Issue 3, pages 637–645, May 2006
How to Cite
BROOKER, R. W., SCOTT, D., PALMER, S. C. F. and SWAINE, E. (2006), Transient facilitative effects of heather on Scots pine along a grazing disturbance gradient in Scottish moorland. Journal of Ecology, 94: 637–645. doi: 10.1111/j.1365-2745.2006.01129.x
- Issue published online: 10 APR 2006
- Article first published online: 10 APR 2006
- Received 14 November 2005 revision accepted 6 January 2006 Handling Editor: John Lee
- competition importance;
- competition intensity;
- heather Calluna vulgaris;
- positive plant interactions;
- Scots pine Pinus sylvestris
- 1Facilitation between neighbouring plants can promote species survival and regulate community composition. However, the role of facilitation varies along environmental severity gradients. It is important to understand the shape of this relationship to improve our ability to predict the impact of a changing environment on biodiversity.
- 2We used Scots pine saplings growing within heather to examine the shape of the relationship between facilitative interactions (protection from browsing) and the severity of the environment (deer browsing intensity). We also investigated whether protection from browsing translated into a biomass response of saplings.
- 3In the first winter following planting heather had a facilitative effect on saplings by reducing the probability of browsing. This effect was strongest at intermediate deer browsing intensities, thus producing a hump-backed relationship between facilitative effects and the severity of the environment.
- 4Protection from browsing did not lead to longer-term biomass gains for the saplings. The competitive effects of heather on sapling growth therefore outweighed the beneficial effects of protection from browsing.
- 5These results provide much-needed information on the shape of the severity–interactions relationship with respect to a key natural disturbance phenomenon (herbivory), and demonstrate that an observable interaction relationship does not necessarily translate into a biomass response.
- 6This illustrates the complex and potentially transient nature of plant–plant interactions, and the potential difficulty that would be associated with using shelter effects of heather as a management tool to promote Scots pine regeneration.