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BLM Final Environmental Assessment DOI-BLM-NV-W010-2012-0055-EA Owyhee Complex Herd Management Area Gather Humboldt River Field Office /Nevada October 2012 Prepared by: U.S. Bureau of Land Management U.S. Bureau of Land Management Winnemucca District Office Elko District Office 5100 E. Winnemucca Blvd. 3900 Idaho Street Winnemucca NV 89445-2921 Elko, Nevada 89801-4211 It is the mission of the Bureau of Land Management to sustain the health, diversity, and productivity of the public lands for the use and enjoyment of present and future generations. DOI-BLM-NV-W010-2012-0055-EA Contents Page Figures............................................................................................................................................ ix Tables ............................................................................................................................................. ix Acronyms ........................................................................................................................................ x Chapter 1. Introduction ................................................................................................................... 1 1.1 Background ........................................................................................................................ 3 1.1.1 October 2012 Site Assessment................................................................................... 8 1.2 Purpose and Need for Action ........................................................................................... 12 1.3 Decision to be Made ........................................................................................................ 12 1.4 Scoping, Public Involvement and Issues ......................................................................... 13 Chapter 2. Action Alternatives ..................................................................................................... 15 2.1 Actions Common to Alternatives A-C ............................................................................ 15 2.2 Alternative A. Phased-in Gather, Selective Removal, and Population Growth Control. .................................................................................................................................. 18 2.3 Alternative B. Selective Removal of Excess Wild Horses to Low AML and Population Growth Control.................................................................................................... 19 2.4 Alternative C. Remove Excess Wild Horses to within AML without Population Growth Control.................................................................................................... 20 2.5 Alternative D. No Action Alternative .............................................................................. 20 2.6 Alternatives Considered but not Analyzed in Detail ....................................................... 20 2.6.1 Use of Bait and/or Water Trapping Only ................................................................. 20 2.6.2 Field Darting PZP Treatment ................................................................................... 21 2.6.3 Gathering the Owyhee Complex to High AML ....................................................... 21 2.6.4 Control of Wild Horse Numbers by Natural Means ................................................ 22 2.6.5 Raising the Appropriate Management Levels for Wild Horses ............................... 22 2.6.6 Remove or Reduce Livestock within the Owyhee Complex ................................... 22 2.6.7 Control of Wild Horse Numbers by Fertility Control Treatment Only ................... 23 2.6.8 Make Individualized Excess Wild Horse Determinations Prior to Removal ............................................................................................................................ 24 2.6.9 Use of Alternative Capture Techniques Instead of Helicopter Capture .................. 25 2.6.10 Designation of the HMAs to be Managed Principally for Wild Horses. ............... 26 2.7 Conformance .................................................................................................................... 26 2.8 Relationship to Laws, Regulations and other Plans ......................................................... 27 2.9 Conformance with Rangeland Health Standards and Guidelines .................................... 27 Chapter 3. Affected Environment: ................................................................................................ 28 3.1 General Description of the Affected Environment .......................................................... 28 3.2 Supplemental Authorities ................................................................................................ 28 iv 3.2.1 Cultural Resources ................................................................................................... 29 3.2.2 Invasive, Nonnative Species .................................................................................... 29 3.2.3 Migratory Birds ........................................................................................................ 30 3.2.4 Native American Religious Concerns ...................................................................... 31 3.2.5 Threatened and Endangered Species ....................................................................... 32 3.2.6 Water Quality (Surface) ........................................................................................... 35 3.2.7 Wetlands and Riparian Zones .................................................................................. 35 3.3 Additional Affected Resources ........................................................................................ 38 3.3.1 Fisheries ................................................................................................................... 38 3.3.2 Public Health and Safety .......................................................................................... 38 3.3.3 Rangeland Management........................................................................................... 39 3.3.4 Recreation ................................................................................................................ 45 3.3.5 Soils.......................................................................................................................... 45 3.3.6 Special Status Species .............................................................................................. 46 3.3.7 Vegetation ................................................................................................................ 48 3.3.8 Wild Horses ............................................................................................................. 50 3.3.9 Wilderness Study Areas ........................................................................................... 59 3.3.10 Wildlife .................................................................................................................. 61 Chapter 4. Environmental Effects ................................................................................................. 63 4.1 Cultural Resources ........................................................................................................... 63 4.1.1 Impacts from Actions Common to Alternatives A-C .............................................. 63 4.1.2 Impacts from Alternative A ..................................................................................... 63 4.1.3 Impacts from Alternative B ..................................................................................... 63 4.1.4 Impacts from Alternative C ..................................................................................... 64 4.1.5 Impacts from Alternative D ..................................................................................... 64 4.2 Invasive, Nonnative Species ............................................................................................ 64 4.2.1 Impacts from Actions Common to Alternatives A-C .............................................. 64 4.2.2 Impacts from Alternative A ..................................................................................... 65 4.2.3 Impacts from Alternative B ..................................................................................... 65 4.2.4 Impacts from Alternative C ..................................................................................... 65 4.2.5 Impacts from Alternative D ..................................................................................... 65 4.3 Migratory Birds ............................................................................................................... 66 4.3.1 Impacts from Actions Common to Alternatives A-C .............................................. 66 4.3.2 Impacts from Alternative A ..................................................................................... 66 4.3.3 Impacts from Alternative B ..................................................................................... 66 4.3.4 Impacts from Alternative C ..................................................................................... 67 4.3.5 Impacts from Alternative D ..................................................................................... 67 4.4 Native American Religious Concerns ............................................................................. 67 v 4.4.1 Impacts from Actions Common to Alternatives A-C .............................................