Document: PAU-3-68-37

Effects of fire and post-burn treatments on native and exotic vascular plant richness and cryptobiotic soils in Grand Staircase-Escalante National Monument, Utah.

EVANGELISTA, P.H.* ¹, Y.OTSUKI ¹ and T.J.STOHLGREN ²

Colorado State University, Ft. Collins, CO 80523-1499 USA ¹
Midcontinent Ecological Science Center, U.S. Geological Survey, Ft. Collins, CO 80525 USA ²

Abstract:
The susceptibility of native vascular plant communities to post-burn seeding and exotic plant invasion were examined on four natural burn areas in the southwest corner of the Grand Staircase-Escalante National Monument, Utah. Using the modified-Whitaker nested vegetation sample plots, we evaluated native and exotic plant diversity, cryptobiotic crust development, and soils between burned sites and unburned sites and post-burn treatment (drill seeding) and non-treatment as part of a long-term monitoring program in the Monument. Preliminary analyses shows native and exotic plant richness in burned sites were 73% and 160% of adjacent unburned areas while the cover of exotic cheatgrass (Bromus tectorum) was greater than 100% in the burned sites compared to unburned sites. Cryptobiotic crust cover, in burned sites, was reduced to 21% compared to adjacent unburned averages. Burn areas with post-burn treatments showed that drill seeding reduced native species richness to 61% and cryptobiotic crust cover to 17% of averages in burn areas with no post-burn seeding, and increased exotic species richness by 30% and the cover of cheatgrass by more than 150% (averaging 30% cover in treated sites). Fire and post-burn treatments reduces native plant richness and cryptobiotic soil crusts assisting the spread and dominance of invasive plant species.

Keywords: Exotic plant invasion, Species richness, Cryptobiotic soils, Post-burn treatment, Grand Staircase-Escalante National Monument

This abstract is being presented at: 10:30 AM in session:
Poster Session #12: Disturbance Ecology.