Assessment Forest Plan Revision Final Nonforested Terrestrial Ecosystems Report Prepared by: Kim Reid Rangeland Management Specialist for: Custer Gallatin National Forest February 16, 2017 1 Custer Gallatin National Forest Assessment – Nonforested Terrestrial Ecosystems Contents Introduction .................................................................................................................................................. 1 Process, Methods and Existing Information Sources .................................................................................... 2 Scale .............................................................................................................................................................. 3 Current Forest Plan Direction ....................................................................................................................... 4 Custer Forest Plan ..................................................................................................................................... 4 Gallatin Forest Plan ................................................................................................................................... 7 Existing Condition ......................................................................................................................................... 7 Key Ecosystem Components ..................................................................................................................... 7 Structure and Composition ................................................................................................................... 8 Pattern and Processes ........................................................................................................................ 55 Key Benefits to People ................................................................................................................................ 61 Trends and Drivers ...................................................................................................................................... 63 Climate .................................................................................................................................................... 64 Fire .......................................................................................................................................................... 67 Herbivory ................................................................................................................................................. 74 Grazing ................................................................................................................................................ 74 Beaver ................................................................................................................................................. 75 Insect Outbreaks ................................................................................................................................. 76 Key Findings ................................................................................................................................................ 77 Information Needs ...................................................................................................................................... 81 References .................................................................................................................................................. 82 General .................................................................................................................................................... 82 Pre-settlement ........................................................................................................................................ 83 Riparian ................................................................................................................................................... 84 Grasslands ............................................................................................................................................... 85 Sagebrush ................................................................................................................................................ 87 Juniper ..................................................................................................................................................... 88 Green Ash ................................................................................................................................................ 88 Aspen and Cottonwood .......................................................................................................................... 89 Aspen .................................................................................................................................................. 89 Cottonwood ........................................................................................................................................ 90 Alpine ...................................................................................................................................................... 90 Plant Materials ........................................................................................................................................ 91 Appendix A – Non-Forest Life Forms and Cover Types (VMap) .................................................................. 93 i Custer Gallatin National Forest Assessment – Nonforested Terrestrial Ecosystems Tables Table 1. Key ecosystem components – non-forested ecosystems .............................................................. 8 Table 2. Non-forested potential vegetation groups for the Custer Gallatin National Forest .................... 13 Table 3. Forested and non-forested potential by habitat type groups within assessment montane and pine savanna areas (forest inventory and analysis). ......................................................... 14 Table 4. Potential forested and non-forested vegetation by landscape area (forest inventory and analysis). ................................................................................................................................... 15 Table 5. Custer Gallatin National Forest habitat types/community types/plant associations (HTs/CTs) ................................................................................................................................... 15 Table 6. Custer Gallatin National Forest estimated # plant species and # HTs/CTs by landscape area .... 16 Table 7. National Forest System acres and proportion of existing vegetation: forested, non- forested, and transitional forested vegetation (Region 1 existing vegetation database) ........ 17 Table 8. Existing non-forested cover types ................................................................................................ 17 Table 9. Riparian vegetation cover types and acreage by landscape area (National Forest System) ....... 19 Table 10. Riparian vegetation and associated corridor vegetation acreage by ownership within the proclaimed boundary of the Custer Gallatin National Forest .................................................. 20 Table 11. Montane units – acres of riparian vegetation cover types by ownership ................................. 21 Table 12. Pine savanna units – acres of riparian vegetation cover types by ownership ........................... 23 Table 13. Total National Forest System primary rangeland and amount of riparian vegetation within primary rangeland vegetation .................................................................................................. 25 Table 14. National Forest System acreage of grasslands and shrublands by landscape area, VMap 2015 .......................................................................................................................................... 27 Table 15. Acreage of greater sage-grouse habitat by landscape area ....................................................... 31 Table 16. Acreage of greater sage-grouse habitat within permitted grazing allotments .......................... 31 Table 17. Acreage of invasive species found within greater sage-grouse habitat ..................................... 32 Table 18. Amount of core (priority) and general greater sage-grouse habitat by wildfire burn severity (acres) .......................................................................................................................... 33 Table 19. National Forest System acreage of juniper and limber pine woodlands by landscape area, VMap 2015................................................................................................................................ 33 Table 20. National Forest System acreage of deciduous broadleaf woodlands by landscape area, VMap 2015................................................................................................................................ 35 Table 21. Pine savanna units – green ash cover types ............................................................................... 37 Table 22. National Forest System acreage of deciduous broadleaf woodlands by landscape area, VMap 2015................................................................................................................................ 39 Table 23. Acreage of aspen by landscape area and ownership ................................................................. 42 Table 24. Acreage