In Colorado subalpine meadows, nonnative dandelions co-occur with a native flower, the larkspur  Bumblebees visit both species, creating the potential for interactions between the two species with respect to pollination  In a recent study, researchers selected 16 plots containing both species  all dandelions were removed from eight plots  the remaining eight control plots were left undisturbed
The control plots yielded significantly more larkspur seeds than the dandelion-free plots, leading the researchers to conclude that the presence of dandelions facilitates pollination (and hence seed production) in the native species by attracting more pollinators to the mixed plots
In mixed plots, pollinators can transfer pollen from one species to another to augment seed production.