Abstracts

SEARCH Open Science Meeting

October 27, 2003
Seattle, Washington, USA

Plant and Soil Responses to Neighbor Removal and Fertilization in Acidic Tussock Tundra

Syndonia Bret-Harte1, Erica A. Garcia2, Vinciane M. Sacré3, Joshua R. Whorley4, Joanna L. Wagner5, Suzanne C. Lippert6, Terry Chapin7
1Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967, ffmsb@uaf.edu
2Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967
3Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967
4Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967
5Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967
6Institute of Arctic Biology, University of Alaska, Room 311, Irving I Bldg., Fairbanks, AK, 99775, USA, Phone 907-474-5434, Fax 907-474-6967
7Institute of Arctic Biology, University of Alaska Fairbanks, PO Box 757000, Fairbanks, AK, 99775-7000, USA, Phone 907-474-7922, Fax 907-474-6967, terry.chapin@uaf.edu

Studies in tundra at Toolik Lake suggest that the characteristics of the dominant plant species may affect the rates of biogeochemical cycling of carbon and nitrogen. For example, the shrub Betula nana becomes dominant in fertilized tussock tundra, leading to greater above-ground storage of carbon in woody biomass than in fertilized non-acidic tundra, where Betula is rare. As climate changes, nutrient availability is expected to increase, and species composition is expected to shift.

To what extent do species characteristics affect ecosystem capacity to respond to perturbation, and the trajectory of response? If plant species coexist in tundra by partitioning soil nitrogen, can they use soil resources freed up by shifts in species composition? In an experimental manipulation, we removed single species and groups of species, in the presence and absence of fertilization, starting in 1997. After two years of treatment, vascular plants mostly responded positively to fertilization, but did not show many significant responses to neighbor removal. However, removal greatly increased soil nutrient availability, particularly in treatments that removed the most plant biomass. Whether plants will be able to take advantage of increased nutrient availability over the longer term, or whether these nutrients will be lost from this ecosystem, remains to be seen.

Abstract Categories: Biological Feedbacks

Back to main abstract page

Previous Abstract | Next Abstract