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Response of Grassland Birds in Sand Shinnery Oak Communities Restored Using Tebuthiuron and Grazing in Eastern New Mexico

Authors

  • Lindsay A. Smythe,

    Corresponding author
    1. Department of Natural Resources Management, Texas Tech University, Box 42125, Lubbock, TX 79409, U.S.A.
    2. Present address: Kofa National Wildlife Refuge, 9300 E. 28th street, Yuma, AZ 85365, U.S.A.
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  • David A. Haukos

    1. Department of Natural Resources Management, Texas Tech University, Box 42125, Lubbock, TX 79409, U.S.A.
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L. A. Smythe, email lindsay_smythe@fws.gov

Abstract

Sand shinnery oak (Quercus havardii) communities are a unique component of grassland bird habitat in eastern New Mexico and have been impacted by human activities for decades. These communities are frequently managed with livestock grazing and herbicide application for shrub control, strategies that potentially can be used to restore the historical shrub–grass composition of this plant community. During spring migration and the breeding seasons of 2004 and 2005, we compared density and community structure of grassland bird species among four combinations of tebuthiuron application and grazing treatments that were being evaluated for restoration of shinnery oak communities. We performed biweekly point transects on sixteen 65-ha study plots in these communities. Density of all avian species combined did not differ between grazed and ungrazed plots. Tebuthiuron-treated plots had a 40% higher average density for combined species than untreated plots. There was a 41% higher average density of all species during spring 2005 than 2004, but density was similar during the breeding season of both years. These trends were predominantly influenced by densities of migratory Cassin’s Sparrow (Aimophila cassinii), which were greater in tebuthiuron-treated plots in both years. Densities of resident Meadowlarks (Sturnella spp.) exhibited little response to tebuthiuron or grazing treatments. Avian species richness, evenness, and diversity were only minimally affected by the tebuthiuron and grazing treatments. This study occurred over a period of highly variable precipitation, so future assessments, spanning longer wet–dry cycles and maturing plant communities, may be necessary to completely determine avian response to these restoration efforts.

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