FIG. 2.

Number of soil bacteria isolated on YTS 250 medium from an unvegetated mixture (•), grasses-legume mixture 1 (▾), and native grasses mixture 2 (○) that contained a gene involved in hydrocarbon degradation, alkB, ndoB, or xylE. Error bars (n = 4) represent one standard error and may be obscured by the data points. The dashed and solid lines indicate the gene prevalence in the planted and unplanted treatments averaged over all the sampling times.