1 The distribution of different plant growth-forms may be caused by interac
tions among plants. Previous studies show that prairie and forest vegetatio
n have different competitive effects and also influence both resource avail
ability and soil community structure.
2 I used a field experiment to distinguish between short-term competitive e
ffects and the long-term effects of vegetation on soils. Soil cores were re
ciprocally transplanted between prairie and forest sites. Seedlings of a gr
ass (Bouteloua gracilis) and a shrub (Elaeagnus commutata) were planted int
o 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 growt
h was suppressed by neighbours to about the same extent in prairie, but onl
y Bouteloua growth was suppressed in forest, resulting in a significant int
eraction between environment and competition. All except one of the interac
tions involving soil origin were not significant, suggesting that plant-soi
l feedbacks did not modify the effects of competition or environment.
4 The results suggest that environment and competition have much larger inf
luences on the performance of juvenile plants in the field than does soil o
rigin. Further work is needed to determine the relative importance of resou
rce competition and soil community effects on plant performance among speci
es and study systems.