Plant and soil responses to neighbour removal and fertilization in Alaskan tussock tundra
Article first published online: 23 JUL 2004
Journal of Ecology
Volume 92, Issue 4, pages 635–647, August 2004
How to Cite
BRET-HARTE, M. S., GARCÍA, E. A., SACRÉ, V. M., WHORLEY, J. R., WAGNER, J. L., LIPPERT, S. C. and CHAPIN, F. S. (2004), Plant and soil responses to neighbour removal and fertilization in Alaskan tussock tundra. Journal of Ecology, 92: 635–647. doi: 10.1111/j.0022-0477.2004.00902.x
- Issue published online: 23 JUL 2004
- Article first published online: 23 JUL 2004
- Received 3 November 2003 revision accepted 22 March 2004 Handling Editor: John Lee
- plant functional types;
- soil nutrient availability;
- species interactions
- 1Species interactions will probably be important in determining plant community structure as availability of soil nutrients changes due to climate warming or anthropogenic N deposition. We removed dominant species, combinations of species, and entire plant functional types, in fertilized and unfertilized plots in tussock tundra.
- 2After 2 years, graminoids responded more strongly to fertilizer than other growth forms, and the responses of graminoids and deciduous shrubs to fertilizer were greater under neighbour removal than in the intact community. Deciduous shrubs, evergreen shrubs and graminoids increased their biomass with fertilization, whereas non-vascular plants decreased.
- 3Dominant species from each growth form usually responded strongly to fertilization, but half of all subdominant species responded weakly or not at all. Few species responded to neighbour removal.
- 4Soil nutrient availability, however, was elevated significantly by both fertilization and neighbour removal. Neighbour removal increased nutrient availability in fertilized plots by up to two orders of magnitude, and availability of and in some unfertilized removal treatments was greater than in the fertilized intact community.
- 5The failure of many plant species to respond with enhanced growth to soil nutrients made available by neighbour removal, despite their response to fertilization, could be due to (i) tundra plants having such rigid niche complementarity that they are unable to utilize these additional resources, or (ii) insufficient time having elapsed for the remaining species to respond, because nutrients derived from neighbour removal probably became available later than nutrients added as fertilizer.
- 6There may be a high potential for loss of available nutrients from the tundra ecosystem when species composition changes, if the remaining plants cannot adjust to use nutrients made available by the loss of their neighbours.