Plant and Soil Consequences of Shrub Management in a Big Sagebrush-Dominated Rangeland Ecosystem

Justin D Derner,Ronald F Follett,Gerald E Schuman,George F Vance

doi:10.5539/enrr.v4n1p19

Justin D Derner, Ronald F Follett + Show 2 more

Open Access

https://doi.org/10.5539/enrr.v4n1p19

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Abstract

This study investigated plant and soil (organic carbon, SOC) responses to shrub management in western U.S. rangeland dominated by Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young). Plants and soils were sampled in 2009 from paired sets of treatments (mowing to 10 cm height, aerial herbicide application of Spike® 20P [tebuthiuron]) in Sandy and Loamy ecological sites. Plant responses to mowing were consistent for both ecological sites with 1) no effects on live, but three- to four-fold increases in dead, Wyoming big sagebrush plant density, 2) reduced height and cover of Wyoming big sagebrush, 3) increased cover of perennial grasses, and 4) no effects on bare ground. For soils, increased SOC did occur with herbicide application in the Loamy site for both the 0-5 cm (43% increase) and 5-15 cm (17% increase) soil depths, which corresponded to annual soil C sequestration rates of 0.16 and 0.14 Mg C ha-1 yr-1 for the 0-5 and 5-15 cm soil depths, respectively. Shrub management in Wyoming big sagebrush-dominated rangelands affects the plant component for two different ecological sites, whereas effects on SOC were observed only when density of live Wyoming big sagebrush plants was reduced through selective herbicide use.

Highlights

The world’s rangelands represent a very large and diverse land resource, and encompass broad temperature and precipitation gradients
Soil C and N did not differ between samples collected at the dripline and between the Wyoming big sagebrush plants (P > 0.05), so the dripline and interspace data values were pooled for analyses
Plant consequences of shrub management treatments in Wyoming big sagebrush-dominated rangelands of southwestern Wyoming on two different ecological sites were consistent for responses to mowing for the Sandy Ecological Site (SES) and Loamy Ecological Site (LES) through 1) no effects on live, but three- to four-fold increases in dead, Wyoming big sagebrush plant densities, 2) reduced height and cover of Wyoming big sagebrush, 3) increased cover of perennial grasses, and 4) no effects on bare ground

Summary

Introduction

The world’s rangelands represent a very large and diverse land resource, and encompass broad temperature and precipitation gradients. Interactions of climate, vegetation and management affect ecosystem responses such as the rate and amount of soil carbon (C) sequestered and the dynamics of individual C pools (Derner, Boutton, & Briske, 2006; Derner & Schuman, 2007; Ingram et al, 2008; Follett & Reed, 2010; Liebig, Gross, Kronberg, Phillips, & Hanson, 2010; Morgan et al, 2010; Derner & Jin, 2012) Ecosystem consequences such as the size of soil C pools following shrub management in western U.S rangelands, especially those dominated by Wyoming big sagebrush To maintain positive responses in Wyoming big sagebrush communities, subsequent shrub management efforts would need to occur about every 20-30 years (Torell, McDaniel, & Ochoa, 2005)

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