Road permeability issues and solutions for migrating ungulates

1. Road permeability issues and solutions for migrating ungulates

2. General Negative Effects Of Roads Mortality from construction and collisions Habitat fractionation Modified animal behavior Exotic species introduction Restriction of wildlife movement Reduction of gene flow, biodiversity “The definition of a road, as outlined by the United States Forest Service (USFS) IRA process, is any vehicular route that is greater than 50 inches wide and constructed for the purpose of full size vehicle use.” “Wide-ranging species are especially vulnerable to road e??ects. Wolves, bears, and elk have sizeable home ranges that typically require them to cross roads frequently. Moreover, road right- of-ways often attract vertebrate species because they provide good habitat for hunting, grazing, and movement (Oehler and Litvaitis, 1995; Forman and Alexander, 1998). Consequently, the chance of vehicular-caused mortality of large mammals increases.” (Alexander 2000) Trombulak gives a list of negative road effects “The definition of a road, as outlined by the United States Forest Service (USFS) IRA process, is any vehicular route that is greater than 50 inches wide and constructed for the purpose of full size vehicle use.” “Wide-ranging species are especially vulnerable to road e??ects. Wolves, bears, and elk have sizeable home ranges that typically require them to cross roads frequently. Moreover, road right- of-ways often attract vertebrate species because they provide good habitat for hunting, grazing, and movement (Oehler and Litvaitis, 1995; Forman and Alexander, 1998). Consequently, the chance of vehicular-caused mortality of large mammals increases.” (Alexander 2000) Trombulak gives a list of negative road effects

3. Methods of Observing Crossings GPS Video Tracks Collisions “Video surveillance constituted a valuable means to assess and compare wildlife use at our UPs. Though sizable, the cost of video surveillance equipment ($5,000) and power distribu- tion ($2,000) was relatively minor compared to the cost of each UP ($1.5–2 million) and the value of the data in evaluating their effectiveness, improving future UP use, and reducing property loss, human injuries, and potential loss of life.” (Dodd 2007) “We used track count studies, infrared cameras, aerial moose Inventory and GPS – collared moose to examine several aspects of moose and roe deer use of a highway crossing.” (Olsson 2007) “We used two sources of tracking to assess WVC. Our primary source was a long-term statewide accident database maintained by the ADOT Data Management Section (ADOT database; Phoenix, AZ), including WVC. Most records (86.0%) were logged by the Arizona Department of Public Safety (DPS) Highway Patrol, and reflected dispatcher and accident reports; ADOT maintenance personnel made 11.5 percent of the reports. As such, we considered this database to be a relatively consistent long-term accounting of WVC.” (Dodd 2005) Note WVC means wildlife-vehicle collisions “Video surveillance constituted a valuable means to assess and compare wildlife use at our UPs. Though sizable, the cost of video surveillance equipment ($5,000) and power distribu- tion ($2,000) was relatively minor compared to the cost of each UP ($1.5–2 million) and the value of the data in evaluating their effectiveness, improving future UP use, and reducing property loss, human injuries, and potential loss of life.” (Dodd 2007) “We used track count studies, infrared cameras, aerial moose Inventory and GPS – collared moose to examine several aspects of moose and roe deer use of a highway crossing.” (Olsson 2007) “We used two sources of tracking to assess WVC. Our primary source was a long-term statewide accident database maintained by the ADOT Data Management Section (ADOT database; Phoenix, AZ), including WVC. Most records (86.0%) were logged by the Arizona Department of Public Safety (DPS) Highway Patrol, and reflected dispatcher and accident reports; ADOT maintenance personnel made 11.5 percent of the reports. As such, we considered this database to be a relatively consistent long-term accounting of WVC.” (Dodd 2005) Note WVC means wildlife-vehicle collisions

4. Seasonal Ranges Roosevelt and Rocky Mountain elk migrate from one area to another according to season and weather conditions. These two subspecies occupy mountain forests and meadows, valleys, foothills, bottomland wood- lands, and open plains throughout the year. Adequate winter habitat in the form of lowland woodland cover is crucial for elk survival. Loss of winter range to development, logging, grazing, agriculture, and other intensive land uses continues to potentially threaten elk populations in certain areas. Summer Range Elk in the northwest and other regions of the country that experience high snowfall and severe winter conditions typically migrate to higher elevations in summer once adverse winter conditions subside. Protection from human disturbance is a major factor luring elk to summer ranges. A general lack of disturbance provided in the high country woodlands and pastures of national forests, wilderness areas, and national parks makes these lands common elk summer ranges. New grasses and forbs and wood- land cover provide the necessary summer food and cover requirements for elk. In states where weather conditions do not prompt migration, elk summer and winter ranges may differ little from one another provided that necessary food and cover requirements are present. A key element of summer range is suitable areas for calving that are free of disturbance, particularly during May and June when calves are most vulnurable. Winter range In regions in which cold weather and snow prompt migration, elk winter in lower-elevation wooded areas that provide hiding and security cover. Densely wooded lowlands and north/northeast-facing slopes provide valuable hiding cover, and drier, open south/southwest-facing slopes can provide avail- able forage. Because of their large body size and thick coat insulating them from the cold, elk can be found bedding down on open slopes in winter as well. Located together with open woodlands that re- ceive ample sunlight, these habitats create an ideal complex of cover and foraging opportunities that provide elk with suitable winter range. Since human disturbance causes elk to expend more energy, lack of disturbance is also an important factor for good winter habitat. Transitional range Transitional range is used by elk (up through late December) when migrating between summer and winter ranges. Transitional range is commonly made up of habitats such as Douglas fir, as- pen/pine, and other woodland communities inter- mixed with open pasture. These transitional range habitats provide forage needed by elk to build fat reserves in the fall and to support calving in the spring. Since winter range forage quality is typi- cally poor, transitional range can be extremely important in sustaining elk populations. (USDA 1999)Roosevelt and Rocky Mountain elk migrate from one area to another according to season and weather conditions. These two subspecies occupy mountain forests and meadows, valleys, foothills, bottomland wood- lands, and open plains throughout the year. Adequate winter habitat in the form of lowland woodland cover is crucial for elk survival. Loss of winter range to development, logging, grazing, agriculture, and other intensive land uses continues to potentially threaten elk populations in certain areas. Summer Range Elk in the northwest and other regions of the country that experience high snowfall and severe winter conditions typically migrate to higher elevations in summer once adverse winter conditions subside. Protection from human disturbance is a major factor luring elk to summer ranges. A general lack of disturbance provided in the high country woodlands and pastures of national forests, wilderness areas, and national parks makes these lands common elk summer ranges. New grasses and forbs and wood- land cover provide the necessary summer food and cover requirements for elk. In states where weather conditions do not prompt migration, elk summer and winter ranges may differ little from one another provided that necessary food and cover requirements are present. A key element of summer range is suitable areas for calving that are free of disturbance, particularly during May and June when calves are most vulnurable. Winter range In regions in which cold weather and snow prompt migration, elk winter in lower-elevation wooded areas that provide hiding and security cover. Densely wooded lowlands and north/northeast-facing slopes provide valuable hiding cover, and drier, open south/southwest-facing slopes can provide avail- able forage. Because of their large body size and thick coat insulating them from the cold, elk can be found bedding down on open slopes in winter as well. Located together with open woodlands that re- ceive ample sunlight, these habitats create an ideal complex of cover and foraging opportunities that provide elk with suitable winter range. Since human disturbance causes elk to expend more energy, lack of disturbance is also an important factor for good winter habitat. Transitional range Transitional range is used by elk (up through late December) when migrating between summer and winter ranges. Transitional range is commonly made up of habitats such as Douglas fir, as- pen/pine, and other woodland communities inter- mixed with open pasture. These transitional range habitats provide forage needed by elk to build fat reserves in the fall and to support calving in the spring. Since winter range forage quality is typi- cally poor, transitional range can be extremely important in sustaining elk populations. (USDA 1999)

5. Why Did The Ungulate Cross The Road? Seasonal differences in crossing frequencies demonstrate winter effect on mammals Elk winter migration has been associated with an increase in EVC (elk vehicle collisions) Dodd 2005 Elk have been observed summering and wintering on opposite sides of a highway, with short migratory movements crossing the highway. Gagnon 2007. “The recurring pattern of lower elk passage rates in the winter season coincided with the time when migratory elk drop off the Mogollon Rim traveling to wintering areas adjacent to SR 260 (Brown 1990). We believe nonresident elk diluted the in?uence of habituated resident elk. Migratory elk do not appear to exhibit the same propensity for habituation to UP as do resident elk since they typically winter south of the SR 260 corridor and are not exposed to the UP on a regular basis. The seasonal decline in passage rates associated with migrating elk has serious implications for achieving consistent, high yearlong UP passage rates by Elk”. (Dodd 2007) Elk winter migration has been associated with an increase in EVC (elk vehicle collisions) Dodd 2005 Elk have been observed summering and wintering on opposite sides of a highway, with short migratory movements crossing the highway. Gagnon 2007. “The recurring pattern of lower elk passage rates in the winter season coincided with the time when migratory elk drop off the Mogollon Rim traveling to wintering areas adjacent to SR 260 (Brown 1990). We believe nonresident elk diluted the in?uence of habituated resident elk. Migratory elk do not appear to exhibit the same propensity for habituation to UP as do resident elk since they typically winter south of the SR 260 corridor and are not exposed to the UP on a regular basis. The seasonal decline in passage rates associated with migrating elk has serious implications for achieving consistent, high yearlong UP passage rates by Elk”. (Dodd 2007)

6. Factors Influencing Crossing Frequency and Location Elk Season Tolerance Gender Nutrients During migration season, elk are more likely to cross a road at high traffic volumes Steep elevation causes shorter migration periods and more residents Also more motivated to cross in riparian meadow areas. They do shift closer to the highway during lower traffic volumes, but there is a lot of noise in this measurement due to the motivational effects of the landscape Elk that live near roadways are more tolerant of high traffic volumes Males have been documented to have higher sensitivity to roads than females Spring-summer bull crossings related to nutritional demand of antler growth Summer-fall cow crossings related to nutritional demands of lactation “The influence of riparian-meadow habitats is reflected in seasonal fluctuations in EVC and elk crossing patterns. We believe that the high proportion of bull EVC and crossings during late-spring and early-summer were tied to nutri- tional demands associated with antler growth (Bubenik 1982).” (Dodd 2005) Male roe deer used the overpass less During migration season, elk are more likely to cross a road at high traffic volumes Steep elevation causes shorter migration periods and more residents Also more motivated to cross in riparian meadow areas. They do shift closer to the highway during lower traffic volumes, but there is a lot of noise in this measurement due to the motivational effects of the landscape Elk that live near roadways are more tolerant of high traffic volumes Males have been documented to have higher sensitivity to roads than females Spring-summer bull crossings related to nutritional demand of antler growth Summer-fall cow crossings related to nutritional demands of lactation “The influence of riparian-meadow habitats is reflected in seasonal fluctuations in EVC and elk crossing patterns. We believe that the high proportion of bull EVC and crossings during late-spring and early-summer were tied to nutri- tional demands associated with antler growth (Bubenik 1982).” (Dodd 2005) Male roe deer used the overpass less

7. Crossing Structure Design Placement: Habitat quality has shown a relation to preferred crossing areas “Our results for passage rates, probabilities of UP use, and behavioral response led us to reject our hypotheses that no differences existed in elk use between UP and season. The concurrence among these measures underscored the degree of differences in elk use of the 2 UPs. Elk use was dependent on UP, and elk exhibited consistent preference for the east UP.” (Dodd 2007) “Studies assessing the e?cacy of wildlife crossing structures often lead to spurious results because of their failure to address masking e?ects of confounding variables. Confounding variables include variation in human activity, density of crossing structures along the highway corridor, and equality of species’ perceived access to each crossing structure.” (Clevenger 2004)“Our results for passage rates, probabilities of UP use, and behavioral response led us to reject our hypotheses that no differences existed in elk use between UP and season. The concurrence among these measures underscored the degree of differences in elk use of the 2 UPs. Elk use was dependent on UP, and elk exhibited consistent preference for the east UP.” (Dodd 2007) “Studies assessing the e?cacy of wildlife crossing structures often lead to spurious results because of their failure to address masking e?ects of confounding variables. Confounding variables include variation in human activity, density of crossing structures along the highway corridor, and equality of species’ perceived access to each crossing structure.” (Clevenger 2004)

8. Conclusions Although a severe ecological barrier, roads are crossed by mammals due to larger forcings Seasonality has a large influence on ungulate movement and sensitivity to roads Crossing structures can mitigate this effect but much more work needs to be done to determine the most effective methods

9. Works Cited S.M. Alexander, N.M. Waters. “The effects of highway transportation corridors on wildlife: a case study of Banff National Park” Transportation Research Part C 8 (2000) 307±320 A.P. Clevenger, N. Waltho. “Performance indices to identify attributes of highway crossing structures facilitating movement of large mammals” Biological Conservation 121 (2005) 453–464 N.L. Dodd, J.W. Gagnon, A.L. Manzo, R.E. Schweinsburg. “Video Surveillance to Assess Highway Underpass Use by Elk in Arizona” JOURNAL OF WILDLIFE MANAGEMENT 71-2 (2007) 637–645 N.L.Dodd, J.W. Gagnon, S. Boe, E.E. Schweinsburg. “Characteristics of elk-vehicle collisions and comparison to GPS-determined highway crossing patterns” (2005) http://repositories.cdlib.org/jmie/roadeco/Dodd2005a S.C. Trombulak, C.A. Frissell. “Review of Ecological Effects of Roads on Terrestrial and Aquatic Communities” Conservation Biology V 14 no.1 (2000) 18-30 USDA “American Elk (Cervus elaphus)” Fish and Wildlife Habitat Management Leaflet no. 11 (1999)