Buffelgrass Effects Above and Belowground in the Sonoran Desert

Abstract

The Sonoran Desert has highly diverse environmental characteristics that produce an extraordinary variety of endemic plant species as well as shaping interactions between them. One crucial interaction in this ecosystem is the dynamic of nurse species, often observed between dominant trees and other native species. Buffelgrass (Cenchrus ciliaris), introduced for cattle production, has become one of the most detrimental invaders in the Sonoran Desert, threatening the dynamic of nurse species since it is known to begin its invasion process in desertscrub under the canopy of trees. This field study investigates the impact of buffelgrass invasion on native vegetation and soil microbial communities under dominant tree species canopies in the Sonoran Desert. Vegetation and soil were sampled from two adjacent sites situated in the Plains of Sonora subdivision of the Sonoran Desert in the core region of buffelgrass invasion in the state of Sonora, Mexico. One of the sites underwent significant transformation, forming a buffelgrass pasture, while the other site retained its native desertscrub vegetation with buffelgrass patches resulting from the invasion process. The results of the vegetation analysis show that site is the primary factor that determines the vegetation richness. In contrast to the vegetation results, the results of the soil analyses indicate that cover type is the primary factor determining the richness and composition of soil microbial communities. Overall, our results provide insights of the above and belowground effects of buffelgrass invasion which can inform management and restoration strategies in uninvaded and invaded desertscrub in the Sonoran Desert.