title: Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra.
abstract: Ecologists have long been intrigued by the ways co-occurring species divide limiting resources. Such resource partitioning, or niche differentiation, may promote species diversity by reducing competition. Although resource partitioning is an important determinant of species diversity and composition in animal communities, its importance in structuring plant communities has been difficult to resolve. This is due mainly to difficulties in studying how plants compete for below-ground resources. Here we provide evidence from a 15N-tracer field experiment showing that plant species in a nitrogen-limited, arctic tundra community were differentiated in timing, depth and chemical form of nitrogen uptake, and that species dominance was strongly correlated with uptake of the most available soil nitrogen forms. That is, the most productive species used the most abundant nitrogen forms, and less productive species used less abundant forms. To our knowledge, this is the first documentation that the composition of a plant community is related to partitioning of differentially available forms of a single limiting resource.
authors.affiliation: US Environmental Protection Agency, Corvallis, Oregon 97333, USA. mckane.bob@epa.gov
authors.forename: Robert B
authors.initials: RB
authors.lastname: McKane
authors.forename: Loretta C
authors.initials: LC
authors.lastname: Johnson
authors.forename: Gaius R
authors.initials: GR
authors.lastname: Shaver
authors.forename: Knute J
authors.initials: KJ
authors.lastname: Nadelhoffer
authors.forename: Edward B
authors.initials: EB
authors.lastname: Rastetter
authors.forename: Brian
authors.initials: B
authors.lastname: Fry
authors.forename: Anne E
authors.initials: AE
authors.lastname: Giblin
authors.forename: Knut
authors.initials: K
authors.lastname: Kielland
authors.forename: Bonnie L
authors.initials: BL
authors.lastname: Kwiatkowski
authors.forename: James A
authors.initials: JA
authors.lastname: Laundre
authors.forename: Georgia
authors.initials: G
authors.lastname: Murray
mesh_terms: D000413:Alaska; D001110:Arctic Regions; D005075:Biological Evolution; D018533:Biomass; D017753:Ecosystem; D004777:Environment; D014644:Genetic Variation; D005998:Glycine / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D018521:Plant Physiological Phenomena; D010944:Plants / Q000145:classification / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012987:Soil / Q000032:analysis
chemical_list: D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012987:Soil; D009584:Nitrogen; D005998:Glycine