J Plant Ecol ›› 2015, Vol. 8 ›› Issue (5): 513-522 .DOI: 10.1093/jpe/rtu039

• Research Articles • Previous Articles     Next Articles

Short-term responses of an alpine meadow community to removal of a dominant species along a fertilization gradient

Wei Li1,2,*, Jimin Cheng1,2, Kailiang Yu3, Howard E. Epstein3 and Guozhen Du4   

  1. 1 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A & F University, 26 Xinong Road, Yangling 712100, China; 2 Institute of Soil and Water Conservation of Chinese Academy of Sciences and Ministry of Water Resource, 26 Xinong Road, Yangling 712100, China; 3 Department of Environmental Sciences, University of Virginia, 291 McCormick Road, Charlottesville, VA 22904–4123, USA; 4 State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, 222 Tianshui Road, Lanzhou 730000, China
  • Received:2014-05-28 Accepted:2014-11-22 Published:2015-09-16
  • Contact: Li, Wei

Short-term responses of an alpine meadow community to removal of a dominant species along a fertilization gradient

Abstract: Aims The relationship between biodiversity and ecosystem functioning has intrigued ecologists for several decades, but the effect of loss of a dominant species on community structure and functioning along a nutrient gradient remains poorly understood. The aim of this paper was to test the effect of a dominant species on community structure and function by conducting a species removal experiment along a fertilization gradient.
Methods We removed the population of a dominant species (Elymus nutans) in a long-term fertilization field in an alpine meadow on the Tibetan Plateau, China. Univariate general linear models were used to evaluate the effects of fertilization and removal on above-ground vegetation characteristics, including photosynthetically active radiation in the understory, species richness, Shannon–Weiner diversity index, Simpson's dominance index, above-ground biomass (including different functional groups) and seedling richness and density.
Important findings Results revealed that after two plant growing seasons, there was no significant effect of the removal of a dominant species on species richness and diversity of the remaining vegetation, but the biomass of forbs and seedling recruitment were significantly increased indicative of the potential for long-term effects. Moreover, removal had a large effect at high fertilization levels, but little effect when fertilization levels were low. Our studies indicated that community response to loss of a dominant species was mainly dependent on resource availability and the remaining functional group identities. We also found seedling recruitment was usually more sensitive to the influence of competition of dominant species than the established vegetation in the short term.

Key words: alpine meadow, competition, dominant species, fertilization, removal, Tibetan Plateau

摘要:
Aims The relationship between biodiversity and ecosystem functioning has intrigued ecologists for several decades, but the effect of loss of a dominant species on community structure and functioning along a nutrient gradient remains poorly understood. The aim of this paper was to test the effect of a dominant species on community structure and function by conducting a species removal experiment along a fertilization gradient.
Methods We removed the population of a dominant species (Elymus nutans) in a long-term fertilization field in an alpine meadow on the Tibetan Plateau, China. Univariate general linear models were used to evaluate the effects of fertilization and removal on above-ground vegetation characteristics, including photosynthetically active radiation in the understory, species richness, Shannon–Weiner diversity index, Simpson's dominance index, above-ground biomass (including different functional groups) and seedling richness and density.
Important findings Results revealed that after two plant growing seasons, there was no significant effect of the removal of a dominant species on species richness and diversity of the remaining vegetation, but the biomass of forbs and seedling recruitment were significantly increased indicative of the potential for long-term effects. Moreover, removal had a large effect at high fertilization levels, but little effect when fertilization levels were low. Our studies indicated that community response to loss of a dominant species was mainly dependent on resource availability and the remaining functional group identities. We also found seedling recruitment was usually more sensitive to the influence of competition of dominant species than the established vegetation in the short term.