Final Environmental Impact Statement Ochoco Summit Trail System Project Chapter 3 – Environmental Consequences – Wildlife
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Final Environmental Impact Statement Ochoco Summit Trail System Project Chapter 3 – Environmental Consequences – Wildlife Wildlife _________________________________________ This section includes a summary of the Wildlife specialist’s report and Biological Evaluation; the entire report is in the Ochoco Summit Trail System project record, located at the Ochoco National Forest, Prineville, Oregon. General Effects to Wildlife With all management activities, there are negative effects to some species and benefits to others that must be considered and balanced along with the need for those human activities. Negative effects of recreational OHV use on wildlife may include wildlife mortality, direct and indirect loss of habitat, displacement, and reduced connectivity. Factors that influence the vulnerability of different wildlife species include behavior and ecology. For example, animals that tend to stay closer to shelter, such as gray squirrel and woodchuck, can tolerate closer encounters with humans because they can quickly escape (Frid and Dill 2002; Gill et al. 1996). Other species tend to forage less and spend less time in quality habitat near human activity (Gill et al. 1996). Still other species may respond positively to human development and use of OHV trails and roads; potential benefits are related to habitat, mobility, and food resources. Openings, shrubs and grasses may develop alongside roads, providing additional foraging habitats. Cleared roads and trails are utilized as travel corridors for some species. No road construction is proposed for the Ochoco Summit project; however, there are ongoing effects of existing roads, and the effects of existing roads and proposed OHV trails are similar. Road widths vary from 14 to 35 feet depending on single or double lane and maintenance of right of way. For trails, effects are less than roads regarding direct alteration of habitat as the width of the footprint for motorcycle trails would be 24 inches wide; ATV trails would be 50 inches wide; and jeep trails would be 80 inches wide. General effects to wildlife include altered reproductive success, mortality, loss of habitat or habitat quality due to: • Access for predators and people • Fragmentation of habitat patches • Behavioral changes in response to human use • Impacts due to noise • Physical alteration of habitat Access for predators and people Roads may act as barriers for some species but may aid in the dispersal of other native and non-native species. Pocket gophers have extended their ranges by traveling on roads and canals (Hey 1941 in Ouren et al. 2007). Brown-headed cowbirds are attracted to trails giving them easier access to parasitize nests near the trail or roads (Hickman 1990). Studies have found predation rates increase with decreasing distance to trails by raven, domestic dogs, mice, squirrels, skunks, and coyotes (Miller and Hubbs 2000; Miller et al. 1998). Roads and trails provide greater human access to habitats previously not accessed (Forman et al. 2003). There is increased human access to and contact with animals resulting in intentional or accidental harm or mortality. Roads and trails also increase access for falconers to remove young raptors from nests (Erdman et al. 1998 in Gaines et al. 2003). Increased contact can result in increased intentional or accidental killing of wildlife, resulting in increased vulnerability of species like mink, marten, deer and elk (Cole et al. 1997; pers. comm. ODFW; Gaines et al. 2003). Edge effect from roads and trails may also increase predation access to songbird nests. Studies found an increase in predators attracted to the corridors and the adjacent forest interior on trails and roads 7 223 Ochoco Summit Trail System Project Final Environmental Impact Statement Chapter 3 – Environmental Consequences – Wildlife to 26 feet (Rich et al. 1994 in Ouren et al. 2007; Hickman 1990). In addition, open areas such as junctions, play areas, campgrounds, and staging areas have perches and a clear view of surrounding areas can be a factor in higher nest predation (Ratti & Reese 1988 in Paton 1994). Adjacent roads and trails provide travel corridors into forested habitat from nearby areas (Small and Hunter 1988; Askins 1994 in Montana TWS 1999). Predators such as great gray owls and red-tail hawks take advantage of forest edge. Roads and 4 wheel drive trails provide additional nesting habitat for these species. Indirect effects would include competition with other predators, such as Goshawk and Coopers hawk. In recent years there have been few restrictions to cross country travel across the Forest except in designated areas (e.g. wilderness, research natural areas, Travel Management Areas, Roadless Areas). Closed roads have administrative use allowed. This use is highly variable in any given year from short-term daily use for a vegetation management project to years of inactivity. Because of the variability and high degree of inactivity these roads are not included in the disturbed habitat analysis. Outside of closed areas cross country travel has been permitted on Ochoco National Forest, and many miles of user-created trails, closed roads, non-motorized trails and other unauthorized routes are receiving motorized use. Within the project area there are 659 miles of roads that are legal for mixed use by OHVs. In addition there are 140 miles of open road that are not legal for OHV use, and 669 miles of closed roads, many of which are receiving OHV use. Given the traditional pattern of “open unless designated closed” on this forest, there are currently large areas with high levels of human disturbance and predator access. The Ochoco Summit project does not propose to construct any new roads. Proposed trail construction would utilize roads, user-created trails, fire lines, snowmobile trails, and other areas disturbed from management activities wherever possible. Through the action alternatives, OHV use would only be allowed on designated trails, routes, shared use roads and/ or play areas, and would no longer be permitted on user-created trails. Within each action alternative, there is a proposal to decrease habitat disturbance by closing and rehabilitating user-created trails, physically closing roads that are not managed as open roads, and converting roads into trails. Table 89 displays the length of trail by existing disturbance type. “Miles of trail not on roads” includes new routes, as well as routes on existing disturbance that are not recognized in GIS as Forest System Roads (ie. temporary roads, skid roads, user created trails, or old roads that have been removed from the transportation database). A combination of rehabilitation of unwanted user created or unauthorized routes and reinforcement of existing road closures would be implemented, which should ameliorate effects of human access across the project area. However, closed roads, converted trails and rehabilitated routes may still provide access for predators. Given the relatively open travel conditions present across much of the project area for hunters and predators alike, it is assumed that animal mortality rates would be similar to what currently exists. Table 89. Comparison of Alternative Actions. Miles of Miles of trails Miles of trail Miles of trails Miles of mixed use on Alternative route on open on closed trails not (OHV decommissioned roads roads on roads legal) road roads Alternative 1 659 0 0 0 0 Alternative 2 659 46 44 11 69 Alternative 3 659 13 30 7 50 Alternative 4 659 53 62 14 81 224 Final Environmental Impact Statement Ochoco Summit Trail System Project Chapter 3 – Environmental Consequences – Wildlife Fragmentation of habitat patches Roads contribute to forest fragmentation by dissecting large patches into smaller patches. Forest fragmentation results in decreased interior forest habitat and increased edge habitat (Askins et al. 1987; Small and Hunter 1988; Schonewald-Cox and Buechner 1992; Askins 1994 in Montana TWS 1999; Reed et al. 1996). Patch size and distribution can determine the probability that a patch may be occupied (Laan and Verboom 1990; Fahrig 1998 in Montana TWS 1999). Habitat fragmentation from roads and 4-wheel-drive trails may reduce a species capacity by disrupting continuous forest cover and reducing space needed by interior species (Hickman 1990 in Montana TWS 1999, Hutto 1996). However, some species such as flycatching birds and accipiters may respond favorably to canopy gaps and corridors, which they utilize as foraging sites or flyways. Riparian areas are usually areas of high diversity. Fragmentation of riparian habitats by roads may create greater impacts on the landscape. Patch size is reduced and roads may separate important habitat associations between the uplands and riparian areas. Songbirds, such as the brown creeper and dark-eyed junco, utilizing both the riparian and upslope forested habitat (McGarigal and McComb 1992) used habitats more effectively when they were connected (Hutto 1995). Road and trail edges may serve as ecological traps for some species (Andrews 1990 in Ouren et al. 2007; Kokko and Sutherland 2001). These areas may have the necessary resources for species to live and potentially reproduce but impose high mortality rates. For example, some bird species are attracted to roadsides due to the lush vegetation for nesting and foraging; although the road and trail sides contains suitable habitat, these individuals are at greater risk of mortality of being hit by vehicles or predation (Clark and Karr 1979 in Ouren et al. 2007, Brooks and Lair 2005; Mumme et al. 2000 in Ouren et al. 2007; Yahner et al. 1979 in Ouren et al. 2007; Kokko and Sutherland 2001). In the Ochoco Summit project area, the more likely potential effect would be increased predation, as risk of animals being hit by an OHV on trails designed for slow speed is low. Forman (2000) described a “road effect distance” of 200 meters (660 feet) for secondary roads to calculate the indirect loss of habitat and the displacement of many species. Forman also mentions the road effect zone is highly variable and is dependent on the species affected, adjacent habitat, road type, and traffic volume.