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Plant responses to competition and soil origin across a prairie-forest boundary

Peltzer, D.A.
Journal of ecology 2001 v.89 no.2 pp. 176-185
Elaeagnus commutata, plant competition, soil biology, mortality, forest soils, prairie soils, plant communities, Saskatchewan
1. The distribution of different plant growth-forms may be caused by interactions among plants. Previous studies show that prairie and forest vegetation have different competitive effects and also influence both resource availability and soil community structure. 2. I used a field experiment to distinguish between short-term competitive effects and the long-term effects of vegetation on soils. Soil cores were reciprocally transplanted between prairie and forest sites. Seedlings of a grass (Bouteloua gracilis) and a shrub (Elaeagnus commutata) were planted into these cores and grown with or without neighbours. 3. Soil origin did not significantly alter the survival, growth or responses to competition of either transplant species. Bouteloua and Elaeagnus growth was suppressed by neighbours to about the same extent in prairie, but only Bouteloua growth was suppressed in forest, resulting in a significant interaction between environment and competition. All except one of the interactions involving soil origin were not significant, suggesting that plant-soil feedbacks did not modify the effects of competition or environment. 4. The results suggest that environment and competition have much larger influences on the performance of juvenile plants in the field than does soil origin. Further work is needed to determine the relative importance of resource competition and soil community effects on plant performance among species and study systems.