Perennial grass recovery following livestock overgazing and shrub removal: an experiment at the Jornada Experimental Range (Jornada Basin LTER), 1996-2016

The objective of this ongoing study is to determine the effect of cattle grazing and shrub removal on the decline and recovery of perennial grasses in a mesquite-invaded black grama grassland on sandy soils in the northern Chihuahuan Desert. The experiment was implemented as a randomized complete block with 3 levels of grazing (summer, winter, and control) and 2 levels of shrub treatment (shrub removal and control) in each of 3 replicate blocks. The 18 experimental units are 0.5 ha (70 x 70 m) exclosures constructed in a mesquite-invaded black grama grassland in the southwest portion of the Jornada Experimental Range in Dona Ana County, New Mexico, USA. Vegetation sampling was conducted with the line-point intercept method. Initial pre-treatment sampling occurred in 1996. Grazing treatments removed 65-80% of aboveground perennial grass biomass over 24-36 hour periods in each of four years from summer 1996 to winter 2000; shrub removal occurred during this time as well. No livestock grazing or shrub removal have occurred since 2000. Post-treatment sampling occurred in 2002, 2009, and 2016.