Vegetation of Two Relict Mesas in Zion National Park

Abstract

Twelve permanent vegetation sampling plots were established on Greatheart and Church mesas in Zion National Park, Utah. Both relict mesas are surrounded by cliffs but contain the same variety of soil conditions as the nearby "mainland." The mesa vegetation was segregated into the following broad community types: mixed conifer forest, ponderosa pine savanna, Gambel oak woodland, pinyon woodland, snowberry-sagebrush steppe, and oak-sagebrush shrubland. Cover of all species was measured in the plots, in addition to tree stem density. Relationships of each community type to topo-edaphic factors and response to fire are noted. The mesa ecosystems can be used as standards to gauge the various effects of resource exploitation on analogous "mainland" areas.