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Species removal and experimental warming in a subarctic tundra plant community

TitleSpecies removal and experimental warming in a subarctic tundra plant community
Publication TypeJournal Article
Year of Publication2009
AuthorsRixen, C, Mulder, CPH

Neighbor interactions are likely to play animportant role in subarctic plant communities. We conductedexperiments in Interior Alaska in which we crossedspecies removal with greenhouse warming manipulations.We examined changes in community biomass, and in plantsurvival and growth of individual species in response toexperimental warming and to: (1) removal of whole speciesversus an equivalent amount of biomass across many species,and (2) removal of subdominant (locally common)versus minor (locally uncommon) plants. Community biomassindicated compensation in growth after removal ofminor species and after biomass removal without eliminationof entire species, but under-compensation afterremoval of subdominants. Growth and survival of individualspecies showed facilitation between some species.Warming increased growth of dominant vascular plants, butat the same time reduced survival, and these impacts weregreater for larger, more mesic species than for the smallerspecies associated with drier habitats. Growth of mosseswas reduced by the warming. Removal eVects did not diVerbetween warming and ambient conditions. The results indicatethat common species are able to reduce resources forothers (competitive eVect) and increase their growth afterneighbor removal, whereas locally uncommon species arenot able to respond rapidly to increased resources madeavailable by neighbor removal. Therefore, the impact of thepresence of common species on locally uncommon specieswas facilitative overall, but not vice versa. The balancebetween disturbances such as changes in temperature andspecies losses from the community will likely be crucial indetermining shifts in subsequent community composition.

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