Effectiveness of Managing Cheatgrass and Other Fine Fuels in Non-Native Dominated Sagebrush Ecological Sites

Location

USU Eccles Conference Center

Event Website

http://www.restoringthewest.org/

Abstract

Managing fire risk by reducing nonnative plants and restoring native plant communities is paramount to habitat conservation and implementing mandates such as Secretarial Order (3336) for Rangeland Fire Prevention, Management and Restoration in the western United States. Nowhere will this effort be more challenging than in the low precipitation (<8-10 inch) areas where repeated fires have resulted in conversion of big sagebrush communities to nonnative annual grasses and forbs. To evaluate potential restoration actions in these dry sites, we treated 48 1-ha experimental plots in nonnative plantdominated communities located within three large replicate blocks with a full-factorial, completely randomized combination of fuel reduction/native plant restoration treatments: mowing, mowing + herbicide, herbicide application, and control (no treatment), with half of all plots seeded with native species. We also out-planted big sagebrush seedlings in some plots the growing season following seeding. Preliminary results suggest that treatment effects on fuels either disappear within the first year, or are often overshadowed by effects of inter-annual variability in precipitation. Seeding of native species was mostly unsuccessful, and out-planted sagebrush seedlings survived for a limited duration during the growing season, likely due to drought conditions. Survival probabilities for sagebrush seedlings did increase with mowing, except when followed by seeding, probably because the soil disturbance from the minimum-till drill led to less bare ground cover. Treatments had no significant effects on soil C decomposition or N mineralization rates. Thus, changes in soil nutrients were unlikely to explain observed treatment effects, or the lack thereof.

Comments

David Pilliod is with the U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center

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Oct 29th, 12:00 PM Oct 29th, 12:30 PM

Effectiveness of Managing Cheatgrass and Other Fine Fuels in Non-Native Dominated Sagebrush Ecological Sites

USU Eccles Conference Center

Managing fire risk by reducing nonnative plants and restoring native plant communities is paramount to habitat conservation and implementing mandates such as Secretarial Order (3336) for Rangeland Fire Prevention, Management and Restoration in the western United States. Nowhere will this effort be more challenging than in the low precipitation (<8-10 inch) areas where repeated fires have resulted in conversion of big sagebrush communities to nonnative annual grasses and forbs. To evaluate potential restoration actions in these dry sites, we treated 48 1-ha experimental plots in nonnative plantdominated communities located within three large replicate blocks with a full-factorial, completely randomized combination of fuel reduction/native plant restoration treatments: mowing, mowing + herbicide, herbicide application, and control (no treatment), with half of all plots seeded with native species. We also out-planted big sagebrush seedlings in some plots the growing season following seeding. Preliminary results suggest that treatment effects on fuels either disappear within the first year, or are often overshadowed by effects of inter-annual variability in precipitation. Seeding of native species was mostly unsuccessful, and out-planted sagebrush seedlings survived for a limited duration during the growing season, likely due to drought conditions. Survival probabilities for sagebrush seedlings did increase with mowing, except when followed by seeding, probably because the soil disturbance from the minimum-till drill led to less bare ground cover. Treatments had no significant effects on soil C decomposition or N mineralization rates. Thus, changes in soil nutrients were unlikely to explain observed treatment effects, or the lack thereof.

https://digitalcommons.usu.edu/rtw/2015/Posters/5