Fire in Chihuhahuan desert grassland: effects of vegetation, small mammal populations, and biopedoturbation

We studied the effect of a prescribed burn in a black-grama-(Bouteloua eriopoda)-dominated desert grassland on vegetation, small mammals and biopedoturbation (soil disturbance by animals). The burn was conducted during the hot-dry season just prior to monsoon rains. One month post-burn, there were significant decreases in canopy cover of the grasses (Bouteloua eriopoda, Sporobolus flexuosus, and Aristida purpurea). One year post-burn, percent cover of B. eriopoda remained significantly lower than in unburned areas. There were no differences in cover of all other grass species in burned and unburned plots 1 year after the burn. Fire killed 100% of the snakeweed shrubs (Gutierrezia sarothrae), 77% of the Torrey ephedra (Ephedra torreyana), and 36% of the soap tree yucca (Yucca elata). One year post-burn, the surviving Y. elata were significantly smaller than the soap tree yucca in the unburned sites. The fire resulted in top kill of all P. glandulosa in the burn areas but all of the mesquite resprouted from root crowns within 1 month after the burn. Fire had no effect on the abundance and diversity of small mammals. Area and volume of soil disturbed by animals (ant nest soil mounds, burrowing spider tunnels and ejected soil, and excavations by small mammals) were not significantly different in burned areas and unburned areas. The area and volume of soil in termite galleries and sheeting were significantly larger in the unburned grassland than in the burned areas