APPENDIX B BIOLOGICAL ASSESSMENT SCO/LW552.doc/020710015 Biological Assessment for the Imperial Sand Dunes Recreation Area SCO/LW544.DOC/020700005-BA Contents Section Page 1.0 Introduction ........................................................................................................................ 1-1 1.1 Purpose and Need........................................................................................................ 1-1 1.1.1 Purpose.......................................................................................................... 1-1 1.1.2 Need.............................................................................................................. 1-3 1.2 Consultation to Date.................................................................................................... 1-3 1.3 Interim Closures/Temporary Camping Closure..................................................... 1-4 1.3.1 Peirson’s Milk-vetch .................................................................................... 1-4 1.3.2 Desert Tortoise.............................................................................................. 1-4 2.0 Summary of Actions Prescribed by Draft RAMP........................................................ 2-1 2.1 No Action Alternative ................................................................................................. 2-1 2.2 Description of the Draft RAMP.................................................................................. 2-1 2.3 Management Areas and Actions................................................................................ 2-2 2.4 Management Measures ............................................................................................... 2-2 2.5 Individual Management Areas .................................................................................. 2-4 2.5.1 Mammoth Management Area and Management Measures .................. 2-4 2.5.2 North Algodones Dunes Wilderness Management Area and Management Measures ......................................................................................... 2-5 2.5.3 Gecko Management Area and Management Measures.......................... 2-5 2.5.4 Glamis Management Area and Management Measures ........................ 2-6 2.5.5 Adaptive Management Area and Management Measures .................... 2-7 2.5.6 Olgilby Management Area and Management Measures........................ 2-7 2.5.7 Dune Buggy Flats Management Area and Management Measures ..... 2-7 2.5.8 Buttercup Management Area and Management Measures ................... 2-8 2.5.9 Buffer Zone Management Area and Management Measures................ 2-8 2.6 Biological Resource Goals and Objectives of the RAMP ........................................ 2-8 2.7 RAMP Monitoring Plan............................................................................................... 2-9 3.0 Affected Environment....................................................................................................... 3-1 3.1 Climate........................................................................................................................... 3-1 3.2 Geology.......................................................................................................................... 3-1 3.2.1 Dune System ................................................................................................. 3-1 3.2.2 Soils ................................................................................................................ 3-2 3.3 Water Resources........................................................................................................... 3-2 3.3.1 Surface Waters.............................................................................................. 3-2 3.3.2 Ephemeral Washes....................................................................................... 3-3 3.4 Biological Resources .................................................................................................... 3-3 3.4.1 Habitat Types................................................................................................ 3-3 3.4.2 Species Accounts .......................................................................................... 3-6 4.0 Impacts and Mitigation..................................................................................................... 4-1 4.1 Peirson’s Milk-vetch .................................................................................................... 4-1 SCO/LW544.DOC/020700005-BA DRAFT I CONTENTS 4.1.1 Impacts ...........................................................................................................4-1 4.1.2 Mitigation ......................................................................................................4-6 4.2 Desert Tortoise ..............................................................................................................4-7 4.2.1 Impacts ...........................................................................................................4-7 4.2.2 Mitigation ......................................................................................................4-7 4.3 Flat-tailed Horned Lizard............................................................................................4-9 4.3.1 Impacts ...........................................................................................................4-9 4.3.2 Mitigation ......................................................................................................4-9 5.0 Cumulative Effects .............................................................................................................5-1 5.1 Peirson’s Milk-vetch .....................................................................................................5-1 5.2 Desert Tortoise ..............................................................................................................5-1 5.3 Flat-tailed Horned Lizard............................................................................................5-2 6.0 Literature Cited ...................................................................................................................6-1 7.0 List of Preparers and Contributors..................................................................................7-1 Appendix Plant and Wildlife Species Potentially Occurring Within the Plan Area Tables Table 2-1 Draft RAMP Resource Area Management Activities ........................................2-2 Figures Figure 1-1 Regional Location Map..........................................................................................1-5 Figure 1-2 ISDRA Plan Area ....................................................................................................1-7 Figure 1-3 Interim Closure Areas............................................................................................1-9 Figure 2-1 Proposed Action ...................................................................................................2-11 Figure 3-1 Habitat Types ........................................................................................................3-13 Figure 3-2 Peirson’s Milk-vetch 1998 Distribution .............................................................3-15 Figure 3-3 Peirson’s Milk-vetch 1999 Distribution .............................................................3-17 Figure 3-4 Peirson’s Milk-vetch 2000 Distribution .............................................................3-19 Figure 3-5 Peirson’s Milk-vetch Distribution, March – May 2001....................................3-21 Figure 3-6 Flat-tailed Horned Lizard Distribution (1977-1997) ........................................3-23 Figure 4-1 Recreation Impact Areas and Habitat Types....................................................4-11 Figure 4-2 Recreation Impact Areas and Peirson’s Milk-vetch Distribution ..................4-13 Figure 4-3 Peirson’s Milk-vetch Distribution in Adaptive Management Area ..............4-15 Figure 4-4 Recreation Impact Areas and Flat-tailed Horned Lizard Distribution (1977-1997) .............................................................................................................4-17 II DRAFT SCO/LW544.DOC/020700005-BA 1.0 Introduction The purpose of this Biological Assessment (BA) is to review the Draft Imperial Sand Dunes Recreation Area Management Plan (RAMP) to determine the extent implementation of the RAMP may affect the threatened Peirson’s milk-vetch (Astragalus magdalenae var. peirsonii), threatened desert tortoise (Gopherus agassizii), and proposed threatened flat-tailed horned lizard (Phrynosoma mcallii). The Bureau of Land Management (BLM) is requesting formal consultation on the Peirson’s milk-vetch and desert tortoise, and a formal conference on the flat-tailed horned lizard. Because the RAMP is a planning document, this BA focuses on the effect of management actions to be implemented as a part of this planning effort. The actions addressed within this BA do not fall within critical habitat of any species protected under the Endangered Species Act (ESA). This BA has been prepared in accordance with legal requirements set forth under Section 7 of the ESA (16 U.S.C. 1536(c)), and follows the standards established in the National Environmental Policy Act (NEPA) and ESA guidance established for the BLM. As the lead federal agency, BLM will oversee compliance with laws, ordinances, regulations, and standards (LORS) required for the project, as well