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This ongoing data set contains percent canopy cover estimates of 6 perennial plant species and 3 genera from transects that cross a grazed/ungrazed boundary fenceline of a single exclosure on the New Mexico State University Chihuahuan Desert Rangeland Research Center in Dona Ana County, New Mexico, USA. In the spring of 1982, as part of the establishment of the Jornada Long-Term Ecological Research site in southern New Mexico, a 135 ha portion of a 1500 ha, internally drained, watershed was exclosed from grazing by domestic livestock. Prior to exclosure the watershed, as well as the rest of the Jornada basin, had been moderately to heavily grazed for the past 100 years. Concurrent with grazing, the vegetation had undergone a dramatic change from desert grassland, with an almost continuous cover of C4 perennial grasses, to isolated patches of the original grassland in a mosaic with desert shrub dominated plant communities (Buffington and Herbel, 1965). The exclosure lies along a northeast facing piedmont slope at the base of a steep isolated mountain peak, and covers a variety of component landforms from the foot of the mountain to the basin floor. This provided the opportunity to investigate the response of vegetation with respect to landscape characteristics as well as release from grazing. This data set is limited to 6 perennial species and 3 genera because of the limited taxonomic resolution of the initial sampling in 1982. See data package knb-lter-jrn.210120001 for a dataset that contains all perennial species encountered but begins in 1986 instead of 1982. Sampling occurs approximately every five years; it was last conducted in November 2015 and will take place again in 2020.