Advanced snowmelt causes shift towards positive neighbour interactions in a subarctic tundra community
Article first published online: 26 JUN 2006
Global Change Biology
Volume 12, Issue 8, pages 1496–1506, August 2006
How to Cite
WIPF, S., RIXEN, C. and MULDER, C. P. H. (2006), Advanced snowmelt causes shift towards positive neighbour interactions in a subarctic tundra community. Global Change Biology, 12: 1496–1506. doi: 10.1111/j.1365-2486.2006.01185.x
- Issue published online: 26 JUN 2006
- Article first published online: 26 JUN 2006
- Received 25 October 2005; revised version received 27 January 2006; accepted 22 February 2006
- dwarf shrub heath;
- Empetrum nigrum;
- neighbour removal experiment;
- Vaccinium vitis-idaea;
- winter climate change
Positive and negative species interactions are important factors in structuring vegetation communities. Studies in many ecosystems have focussed on competition; however, facilitation has often been found to outweigh competition under harsh environmental conditions. The balance between positive and negative species interactions is known to shift along spatial, temporal and environmental gradients and thus is likely to be affected by climate change.
Winter temperature and precipitation patterns in Interior Alaska are rapidly changing and could lead to warmer winters with a shallow, early melting snow cover in the near future. We conducted snow manipulation and neighbour removal experiments to test whether the relative importance of positive and negative species interactions differs between three winter climate scenarios in a subarctic tundra community. In plots with ambient, manually advanced or delayed snowmelt, we assessed the relative importance of neighbours for survival, phenology, growth and reproduction of two dwarf shrub species. Under ambient conditions and after delayed snowmelt, positive and negative neighbour effects were generally balanced, but when snowmelt was advanced we found overall facilitative neighbour effects on survival, phenology, growth and reproduction of Empetrum nigrum, the earlier developing of the two target species. As earlier snowmelt was correlated with colder spring temperatures and a higher number of frosts, we conclude that plants experienced harsher environmental conditions after early snowmelt and that neighbours could have played an important role in ameliorating the physical environment at the beginning of the growing season.