Plant mycorrhization is resilient to land use change in a thornscrub in northwestern Mexico

Abstract

Land-use change, such as the conversion of thornscrub to buffelgrass (Cenchrus ciliaris) pastures, poses a significant threat to natural plant communities in northwestern Mexico. However, its effects on arbuscular mycorrhizal fungi (AMF) associations with native plant species remain poorly understood. This study evaluated the impact of such conversion on AMF associations in four native plant species by comparing soil and root samples from a natural thornscrub and a buffelgrass pasture in Sonora, Mexico, during both wet and dry seasons. Mycorrhizal variables measured included root mycorrhizal colonization, visual density, root hair density, spore density, spore viability, AMF spore morphotype diversity, and soil nutrient content. Most mycorrhizal variables did not differ significantly between the two habitats. When significant differences were observed, values tended to be higher in the pasture, possibly reflecting the more stressful conditions of this habitat. A total of 27 AMF spore morphotypes were identified, with a greater number found in the pasture (22) compared to the thornscrub (7); only two morphotypes were shared between the two habitats. These findings suggest that AMF associations in thornscrub are resilient to buffelgrass conversion, with increased mycorrhization and spore density likely linked to the stress conditions of the pasture and dry season.