CHAPTER 1 - INTRODUCTION This document identifies and describes the physical, biological, and human features of Mahogany Creek Watershed. This is a dynamic document subject to change as new information becomes available and data is collected. A multiple discipline team of resource specialists gathered and analyzed data and information currently available. The team developed issues, researched historic and current conditions, determined trends within the watershed, developed desired future conditions (dfc) and recommendations to achieve those dfcs. The analysis was completed during winter 1999, 2000. General Description Mahogany Creek Watershed is located on the Teton Basin Ranger District of the Targhee National Forest along the east side of the Big Hole Mountains and the north side of the Snake River Mountain Range. The watershed includes all of the waters that drain into the Teton River from Teton Pass Highway west to Pine Creek Pass and north to Grandview Point. The analysis area is not a true watershed, but a composite watershed. A true watershed is a fully contained geomorphic unit flowing to a common point (usually the confluence with a larger stream). A composite watershed is a series of smaller watersheds that are grouped together but do not form a “closed system” draining to a common point. The analysis area (42,967 acres) includes all of the National Forest lands, private lands within the National Forest boundary and adjacent Bureau of Land Management (BLM) lands.(See Map 17) Within the analysis area, 1,824 acres are privately owned and 300 acres are managed by BLM; the Forest Service manages approximately 40,843 acres within the analysis area. Land uses on the private lands immediately adjacent to the analysis area are housing developments, ranches and a golf course in the development stages. The adjacent lands will be included in the analysis in general terms because less information was available at the time of the analysis and they impact the resources in the analysis area. Portions of Garns Mountain (19,527 acres) and Palisades (6,302 acres) Roadless Areas are included in the watershed. No new road construction or timber sales (except for stewardship purposes) are allowed with in these areas. This is important in terms of management options. See Map 3 for roadless area locations. The Revised Forest Plan subdivides the Forest into management prescription areas that have specific goals, objectives standards and guidelines. The management prescription areas located within this watershed are Visual Quality Maintenance (2.1.1), Elk and Deer Winter Range (2.7 a), Semi-Primitive Motorized (3.2j,i), Timber Management No Clearcut (5.1.3b), Timber Management Big Game (5.1.4b) and Concentrated Development Areas (8.1). The prescription areas determine management options. See Map 4 for location. Draft1/15/2001 1 The resource areas discussed in the following chapters are as follows. The amount of detail analyzed for each resource was based on the issues listed in the following chapter. A resource that was a component of the watershed but not a main issue was not analyzed in great detail. Physical Resources Geology/Soils Hydrology Biological Resources Vegetation Wildlife Fish Social Resources Cultural Recreation Transportation System Economics Draft1/15/2001 2 CHAPTER 2 – ISSUES AND KEY QUESTIONS Issues and key questions were developed to focus the analysis on specific concerns in the watershed. Indicators were developed for the issues to direct and quantify the analysis. Issues were gathered from the public during a public meeting held on January 4, 2000, through discussions with interested parties, resource specialists knowledge of the area and Line Officer’s purpose for the analysis. The main issues are: ¾ Water quality and watershed improvements ¾ Cutthroat trout habitat improvements ¾ Change in vegetation disturbance regimes ¾ Big game winter range ¾ Canada lynx ¾ Management of roads and trails In addition to the resources covered under the issues, other resource areas were documented in less detail to provide background and an overall picture of the watershed. Issue: Water quality specifically sedimentation and stream function has been affected by construction and use of roads and trails, grazing, decrease in beaver populations, mine tailings and introduction of non-native plant species. Key Questions: How have human disturbances affected water quality? Are the streams and riparian zones resilient and functioning properly? What are the effects and extent of mine tailings? How have natural occurrences affected water quality? What are those occurrences? Are the plant populations within their natural range of variability? What is the status of beaver? Indicators: Miles of roads and trails within riparian corridors Trend in beaver populations Stream characteristics Location and content of mine tailings Trend in plant species – native versus non-native Issue: Introduction of exotic fish species, removal of corridors and de-watering of streams has decreased the native fish populations. Key Questions: Has the introduction of exotic fish species lead to the decline of native fish species and how? Where are the points of stream diversions and how has this affected native fish populations? Are the streams and creeks connected to Teton River and where? Indicators: Trend in cutthroat and brook trout populations Draft1/15/2001 3 Issue: Vegetative structure, composition and function have been altered due to human activities such as fire suppression, grazing, development and logging. Key Questions: What are the main vegetation types? What are the disturbance regimes? How has interruption of natural disturbance processes affected structure, composition and function of vegetative species? How have vegetation patterns changed over time across the landscape and what caused those changes? Are there noxious weeds and exotic plant species in the analysis area and where are they? Indicators: Acres and distribution of vegetative types and age classes Patch size Fire regimes Insect and disease regimes Acres logged and logging method Grazing trends Issue: Past trapping and habitat alteration (roads, logging, fire suppression, grazing) has decreased lynx populations. Key Questions: What is the status of lynx in the watershed? What and where is lynx habitat? How have human activities affected lynx populations and habitat? How have changes in vegetation types, patterns and structure affected lynx? Indicators: Acres of denning and foraging habitat Affects of human access on movement corridors, denning habitat, competition with other predators. Issue: Increased access, development and change in vegetation have decreased big game winter range and caused disturbance and displacement of these animals. Key Questions: How has increased year round human access, development on private lands and motorized access affected the availability and use of critical big game winter range? How has recreation use (roads, atv, hunting) affected wildlife? What is the condition of winter range? Indicators: Acres of big game winter range Trends in vegetation composition, pattern and structure Trends in recreational use on winter range Issue: An increasing and diverse local, regional, national population has demanded a variety of recreational experiences changing recreational use in the Big Holes. Key Questions: What are the current and predicted recreational uses? Draft1/15/2001 4 Are trails and roads adequate to meet current and future recreation needs? Indicators: Number of user days Number of outfitter permits and applications Trail and road condition and stability Types of recreation use Draft1/15/2001 5 CHAPTER 3 – REFERENCE AND CURRENT CONDITION Reference and current conditions were researched for all resources known to occur in the watershed using available literature, forest specialist’s knowledge and anecdotal information. Timeframes for reference and current conditions vary by resource depending on European settler influence. SOILS The timeframes selected for reference conditions for soils are prior to 1840 for riparian soils and prior to 1880 for all other soils. The near elimination of beaver by trappers by 1840 greatly influenced riparian conditions. Permanent European settlers arrived later (1880) and began to harvest timber, graze livestock and suppress fires. Not much information exists on the types of soils present during reference conditions. There have been events in recent history that have changed the soils. Most of the information relates to current conditions of the soils and events leading to these conditions. The following soils information is taken from the Targhee National Forest Ecological Unit Inventory (Bowerman 1999). The acres represent those found in the watershed. See Map XX for locations of the Ecological Units. Table 3-1 EUI Ecological Dominant Current Vegetation Management Limitations Dominant Unit Slopes Soils Number and (acres) 1106 40-70% Sage grass, open canopy Steep slopes limit use of heavy Deep to very (819ac) Douglas fir equipment. Steep slopes also deep limit re-vegetating cut and fill calcareous slopes. soils with high % gravels and cobbles 1130 4-30% Short sod forming Off-road vehicle use limited due Very deep (185ac) grasses and sedges to highly erodible soils. calcareous Fencing is severely limited due soils with high to rocky soils. % gravels and Re-vegetation limited due to cobbles short growing seasons and rocky, droughty soils 1170 4-35% Subalpine High potential for mass Very deep (154ac) fir/gooseberry and tall