Native and introduced seed mix performances on cheatgrass rangelands

Authors: Clements, Darin - Charlie; Harmon, Daniel - Dan

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2019
Publication Date: 2/17/2020
Citation: Clements, D.D., Harmon, D.N. 2020. Native and introduced seed mix performances on cheatgrass rangelands. Society for Range Management Meeting Abstracts. 73:51. February 16-20, 2020 Denver, CO.

Interpretive Summary: Invasion of alien plant species influences many phases of wildland research in the Great Basin. The accidental introduction and subsequent invasion of cheatgrass (Bromus tectorum L.) onto millions of hectares of Great Basin rangelands has led to the conversion of former big sagebrush (Artemisia tridentata Nutt.)/bunchgrass communities to cheatgrass dominance. Cheatgrass has revolutionized secondary succession in more arid big sagebrush plant communities throughout the Great Basin by increasing the chance, rate, spread and season of wildfires. The best known method to suppress cheatgrass densities and associated fuels is through the establishment of perennial grasses. We investigated the performance of native, introduced and native/introduced perennial grass seed mixes following for two consecutive years in northern Nevada. Following weed control efforts using the pre-emergent herbicide, Sulfometuron methyl, we seeded native and introduced perennial grasses in seed mixes to record establishment and the ability of these seed mixes to suppress cheatgrass. Following 2-years of recording seedling emergence and establishment, we recorded 35.5 perennial grasses/m² in the introduced and native mix plots and 25.8/m² in the native/introduced plots for year-1. Year-2 resulted in 27.9 perennial grasses/m² in the introduced and native/introduced plots, while the native plot decreased to 14.0/m². Year-1 received 335.3mm of annual precipitation compared to 201.9mm in year-2. Cheatgrass densities were recorded from a low of 10.8/m² in the year-1 introduced plots to a high of 144.2/m² in the year-2 native plots. Introduced perennial grass seed mix performed the best at suppressing cheatgrass fuels from 1,352 kg/ha in control plots down to 103 kg/ha, while the native/introduced and native plots recorded 151 kg/ha and 381 kg/ha, respectfully. In arid environments introduced perennial grasses and introduced/native perennial grass seed mixes consistently performed better at suppressing cheatgrass than native perennial grass seed mixes which can be attributed to more arid years than mesic years.

Technical Abstract: Invasion of alien plant species influences many phases of wildland research in the Great Basin. The accidental introduction and subsequent invasion of cheatgrass (Bromus tectorum L.) onto millions of hectares of Great Basin rangelands has led to the conversion of former big sagebrush (Artemisia tridentata Nutt.)/bunchgrass communities to cheatgrass dominance. Cheatgrass has revolutionized secondary succession in more arid big sagebrush plant communities throughout the Great Basin by increasing the chance, rate, spread and season of wildfires. The best known method to suppress cheatgrass densities and associated fuels is through the establishment of perennial grasses. We investigated the performance of native, introduced and native/introduced perennial grass seed mixes following for two consecutive years in northern Nevada. Following weed control efforts using the pre-emergent herbicide, Sulfometuron methyl, we seeded native and introduced perennial grasses in seed mixes to record establishment and the ability of these seed mixes to suppress cheatgrass. Following 2-years of recording seedling emergence and establishment, we recorded 35.5 perennial grasses/m² in the introduced and native mix plots and 25.8/m² in the native/introduced plots for year-1. Year-2 resulted in 27.9 perennial grasses/m² in the introduced and native/introduced plots, while the native plot decreased to 14.0/m². Year-1 received 335.3mm of annual precipitation compared to 201.9mm in year-2. Cheatgrass densities were recorded from a low of 10.8/m² in the year-1 introduced plots to a high of 144.2/m² in the year-2 native plots. Introduced perennial grass seed mix performed the best at suppressing cheatgrass fuels from 1,352 kg/ha in control plots down to 103 kg/ha, while the native/introduced and native plots recorded 151 kg/ha and 381 kg/ha, respectfully. In arid environments introduced perennial grasses and introduced/native perennial grass seed mixes consistently performed better at suppressing cheatgrass than native perennial grass seed mixes which can be attributed to more arid years than mesic years.