In this study we surveyed 3 deserts along the extension of the Atacama Desert: Atiquipa (15.7 S), Romeral (29.5 S) and Fray Jorge (30.5 S) over 3 years. Within each desert we sampled 5 sites, each separated at lest 2 km from each other. This allowed us to sample extensively the effects of dominant plants (shrubs) on plant communities within these deserts.
Results, as can be seen in the figures above, indicate that at extreme aridity conditions such as in Romeral and especially Fray Jorge (the most arid sites), dominant plants have a negative effect on both richness and abundance of arid plant communities. Surprisingly at Atiquipa, the strongest positive effects occurred during the driest year of the 3 years surveyed.