Appendix H: Environmental Assessment Appendix H: Environmental Assessment 291 Mark Twain NWR Complex Comprehensive Conservation Plan 294 Chapter 1: Purpose and Need for the Proposed Action .........................................................301 1.1 Purpose and Need for Action ................................................................................ 301 1.1.1 Purpose ........................................................................................................ 301 1.1.2 Need for Action ........................................................................................... 303 1.2 Decision Framework .............................................................................................. 304 1.3 Background ............................................................................................................ 304 1.3.1 The United States Fish and Wildlife Service .............................................. 304 1.3.2 The National Wildlife Refuge System ........................................................ 305 1.3.3 Mark Twain National Wildlife Refuge Complex ........................................ 305 1.3.4 Mark Twain Refuge Complex Vision Statement for Desired Future Condition ............................................................................. 306 1.3.5 Area of Ecological Concern ......................................................................... 307 1.4 Scoping and Public Involvement ........................................................................... 308 1.4.1 Issues and Concern ..................................................................................... 308 1.5 Legal, Policy and Administrative Guidelines ........................................................ 310 1.5.1 Legal Mandates ........................................................................................... 310 Chapter 2: Alternatives Including the Preferred Alternative ...............................................311 2.1 Rationale for Alternative Designs ......................................................................... 311 2.2 Description of Alternatives ................................................................................... 312 2.2.1 Alternative A: Expanded Boundaries, Increased River Connectivity (Preferred Alternative) .................................................................................. 315 2.2.1.1 Background on Land Preservation Component ............................... 315 2.2.1.2 Alternative A, Expanded Boundaries, Increased River Connectivity (Preferred Alternative) Description ............................ 318 2.2.2 Alternative B: Current Program .................................................................. 320 2.2.3 Alternative C: Existing Boundaries, Maximum River Connectivity ............ 320 2.2.4 Alternative D: Existing Boundaries, Least River Connectivity: .................. 321 2.2.5 Elements Common To All Alternatives ....................................................... 321 2.2.5.1 Fire ................................................................................................... 321 2.2.5.1.1 Prescribed Fire ................................................................ 322 2.2.5.1.2 Fire Prevention and Detection ........................................ 323 2.2.5.1.3 Fire Suppression ............................................................. 324 2.2.5.1.4 Listed Species and Other Species of Interest ................ 326 2.2.6 Elements Common to All Alternatives ........................................................ 327 2.2.6.1 Cultural Resources .......................................................................... 327 2.2.6.2 Environmental Justice ..................................................................... 327 2.2.6.3 Climate Change Impacts ................................................................. 327 Chapter 3: Affected Environment ...............................................................................................347 3.1 Description of Existing Units Within Mark Twain NWR Complex ....................... 347 3.1.1 Port Louisa NWR ......................................................................................... 347 3.1.2 Great River NWR and Clarence Cannon NWR ............................................ 347 3.1.3 Two Rivers NWR ......................................................................................... 347 3.1.4 Middle Mississippi River NWR ................................................................... 347 3.2 Habitat Overview .................................................................................................. 348 Appendix H: Environmental Assessment 295 3.2.1 Forested Resources ..................................................................................... 348 3.2.2 Wetland Resources ..................................................................................... 349 3.2.3 Grassland Resources ................................................................................... 349 3.2.4 Invasive Species .......................................................................................... 349 3.2.5 Sedimentation and Water Quality .............................................................. 350 3.2.6 Geomorphology and Soils ........................................................................... 351 3.2.6.1 Geomorphology ............................................................................... 351 3.2.6.2 Soils ................................................................................................ 352 3.3 Wildlife ..................................................................................................................353 3.3.1 Migratory Bird Species ................................................................................ 353 3.3.2 Fish Species ................................................................................................. 353 3.3.3 Freshwater Mussels .................................................................................... 354 3.3.4 Mammals, Upland Game Birds ................................................................... 354 3.3.5 Amphibians and Reptiles ............................................................................ 354 3.3.6 Federally Listed Threatened and Endangered Species ............................... 354 3.3.6.1 Mammals ........................................................................................ 355 3.3.6.2 Birds ................................................................................................ 355 3.3.6.3 Fish .................................................................................................. 356 3.3.6.4 Mussels ........................................................................................... 356 3.3.6.5 Reptiles ........................................................................................... 357 3.3.6.6 Plants .............................................................................................. 357 3.3.6.7 Invertebrates ................................................................................... 357 3.4 Public Use .............................................................................................................. 357 3.5 Socioeconomics .................................................................................................... 358 3.6 Cultural Resources ................................................................................................ 360 Chapter 4: Environmental Consequences ................................................................................ 362 4.1 Effects Common to All Alternatives ...................................................................... 362 4.1.1 Environmental Justice ................................................................................. 362 4.1.2 Cultural and Archaeological Resources ...................................................... 362 4.1.3 Climate Change Impacts ............................................................................. 362 4.1.4 Prescribed Fire as a Management Tool ...................................................... 363 4.1.4.1 Social Implications .......................................................................... 363 4.1.4.2 Cultural and Archaeological Resources .......................................... 364 4.1.4.3 Flora ................................................................................................ 364 4.1.4.4 Listed Species ................................................................................. 365 4.1.4.5 Soils ................................................................................................ 365 4.1.4.6 Escaped Fire .................................................................................... 366 4.1.4.7 Trapping .......................................................................................... 366 4.2 Alternative A: (Expanded Boundaries, Increased River Connectivity) ................. 366 4.2.1 Listed and Other Species of Interest ........................................................... 367 4.2.2 Habitat Management .................................................................................. 367 4.2.3 Sedimentation and Water Quality .............................................................. 368 4.2.4 Floodplain Management ............................................................................. 368 4.2.5 Public Use and Education ...........................................................................