Impact of Recreational Snow Compaction on Small Mammals in the Subnivean Space

1. as recreational use of snow covered areas increases, the potential impacts on those ecosystems also increases, there have been a few studies that have looked at various impacts from noise, pollution, habitat destruction, trail erosion but very little in looking at the impact of recreation on the subnivean space utilized by small animals, the impacts include cross country ski areas, backcountry ski and snowboard use, snowmobile, other various over snow transport, alpine ski runs and lifts combination of literature review and snow compaction experimentas recreational use of snow covered areas increases, the potential impacts on those ecosystems also increases, there have been a few studies that have looked at various impacts from noise, pollution, habitat destruction, trail erosion but very little in looking at the impact of recreation on the subnivean space utilized by small animals, the impacts include cross country ski areas, backcountry ski and snowboard use, snowmobile, other various over snow transport, alpine ski runs and lifts combination of literature review and snow compaction experiment

2. the subnivean space is incredibly important to the winter ecosystems of alpine and sub-alpine regions, the subnivean space is used by many small mammals (voles, mice, etc.) for insulation and movement through the snowpack to food sources, these animals form the base of the winter food web providing food for predators such as the marten, weasel, coyote, lynx, bobcat, raptors, since the margin for survival is small during winter, even small changes can have a large effect on survival rates and composition the subnivean space is incredibly important to the winter ecosystems of alpine and sub-alpine regions, the subnivean space is used by many small mammals (voles, mice, etc.) for insulation and movement through the snowpack to food sources, these animals form the base of the winter food web providing food for predators such as the marten, weasel, coyote, lynx, bobcat, raptors, since the margin for survival is small during winter, even small changes can have a large effect on survival rates and composition

3. small mammals that utilize the subnivean space in our area other areas of the world have similar small mammals using the subnivean space small mammals that utilize the subnivean space in our area other areas of the world have similar small mammals using the subnivean space

4. small mammals that utilize the subnivean space in our area other areas of the world have similar small mammals using the subnivean space small mammals that utilize the subnivean space in our area other areas of the world have similar small mammals using the subnivean space

5. most home range and habitat studies are done in the summer very little research on the effect of snow cover on the home range and activity of small mammals but recent research shows that the snowpack does reduce home range and access to food (even though it is better than no snowpack at all)most home range and habitat studies are done in the summer very little research on the effect of snow cover on the home range and activity of small mammals but recent research shows that the snowpack does reduce home range and access to food (even though it is better than no snowpack at all)

6. predators relying on subnivean animals mink, ermine, weasels, marten, fisher, coyote, bobcat, lynx, raptors/owls any impact on the small mammal populations also affects predators predators relying on subnivean animals mink, ermine, weasels, marten, fisher, coyote, bobcat, lynx, raptors/owls any impact on the small mammal populations also affects predators

7. depth hoar at base of pack causes subnivean space in continental snowpacks maritime snowpacks also have a subnivean space used by small mammals, but is caused not by depth hoar formed through high temperature gradients, but vegetation and microtopography providing spacedepth hoar at base of pack causes subnivean space in continental snowpacks maritime snowpacks also have a subnivean space used by small mammals, but is caused not by depth hoar formed through high temperature gradients, but vegetation and microtopography providing space

9. photo of subnivean space in the snowpack average height of subnivean space in the study area was 16 cm photo of subnivean space in the snowpack average height of subnivean space in the study area was 16 cm

10. in the loose depth hoar of the snowpack in winter, tunnels aren�t readily formed as mammals burrow through the unconsolidated snow as the snow melts out in the spring the snow become denser and more permanent tunnels can be formed and seen when the snow melts outin the loose depth hoar of the snowpack in winter, tunnels aren�t readily formed as mammals burrow through the unconsolidated snow as the snow melts out in the spring the snow become denser and more permanent tunnels can be formed and seen when the snow melts out

11. photo of effect of ski pass on the snowpackphoto of effect of ski pass on the snowpack

12. possible factors affecting changes in the subnivean space load frequency snow depthpossible factors affecting changes in the subnivean space load frequency snow depth

13. Site lodgepole pine forest--typical forest type for recreational use, sparse understory minimizes under snow vegetation variation and the effects of the vegetation on the subnivean space chose open, uniform, undisturbed sites uniform slope with south aspect shaded areas to minimize sun effects and melt/freeze crusts originally measured to get an idea of current long term use effects of trails, dug pits at trails and measured trail and side data dug snow pits approx. 2 meters across and measured snow depth, height of subnivean space from the ground and density of snow in the subnivean space (ground to 10 cm) then walked over area with skis (210 lbs. load with 180 cm skis tested different snow depths with one pass, holding load and frequency constant tested snow depths of 30 cm, 50 cm, 65 cm, 75 cm, 100 cm 3 pits dug for each depth and results averaged tested amount of use (number of passes), holding load and snow depth constant chose snow depth at which there was some compaction effect (65 cm) tested 1, 3, 5, and 10 passes for each pit and measured height and snow density 3 pits tested Site lodgepole pine forest--typical forest type for recreational use, sparse understory minimizes under snow vegetation variation and the effects of the vegetation on the subnivean space chose open, uniform, undisturbed sites uniform slope with south aspect shaded areas to minimize sun effects and melt/freeze crusts originally measured to get an idea of current long term use effects of trails, dug pits at trails and measured trail and side data dug snow pits approx. 2 meters across and measured snow depth, height of subnivean space from the ground and density of snow in the subnivean space (ground to 10 cm) then walked over area with skis (210 lbs. load with 180 cm skis tested different snow depths with one pass, holding load and frequency constant tested snow depths of 30 cm, 50 cm, 65 cm, 75 cm, 100 cm 3 pits dug for each depth and results averaged tested amount of use (number of passes), holding load and snow depth constant chose snow depth at which there was some compaction effect (65 cm) tested 1, 3, 5, and 10 passes for each pit and measured height and snow density 3 pits tested

14. photo of compaction effect of skis in a snow pit after one pass you can see the subnivean space at the bottom and the platform that the ski made about half way up notice that the entire snowpack is compressed to less than half of original depth but that compaction of the upper snow provides some protection to the subnivean space photo of compaction effect of skis in a snow pit after one pass you can see the subnivean space at the bottom and the platform that the ski made about half way up notice that the entire snowpack is compressed to less than half of original depth but that compaction of the upper snow provides some protection to the subnivean space

15. the subnivean space was completely destroyed (compacted) when snow depth was 30 cm as snow depth increases, there is less compaction of the subnivean space, until about 100 cm, where there is enough snow that the upper layers of snow become compacted with very little effect on the lower subnivean spacethe subnivean space was completely destroyed (compacted) when snow depth was 30 cm as snow depth increases, there is less compaction of the subnivean space, until about 100 cm, where there is enough snow that the upper layers of snow become compacted with very little effect on the lower subnivean space

16. snow density increased due to ski compactionsnow density increased due to ski compaction

17. the first pass causes the most compaction to the subnivean space after 3-5 passes, there is little decrease in subnivean space height because most of the compaction has already happenedthe first pass causes the most compaction to the subnivean space after 3-5 passes, there is little decrease in subnivean space height because most of the compaction has already happened

18. snow depth, frequency of use, and type of load are factors influencing subnivean change size and snow density of the subnivean space is affected with snowpack deeper than 100 cm, the snow compaction occurs higher in the snowpack and provides a platform above the subnivean space the maximum compression of the subnivean space occurs after 3-5 ski passes, additional use has little additional effect on the subnivean space there seems to be an effect on the subnivean space, resulting in reduction or compaction of the subnivean space and increasing density of the snow beyond the ability of small mammals to utilize it, essentially this provides barriers and can section home ranges to such an extent that it reduces survival rates due to lack of food access, reduced insulation quality, and increased energy use, also, they may have to travel on the surface to bypass these barriers, increasing predation this compaction may benefit some mammals in the short term, reduced transportation energy use for deer, elk, moose, increased range for coyotes, but can also have far reaching, unexpected effects, lynx decline due to opening of habitat to coyote snow depth, frequency of use, and type of load are factors influencing subnivean change size and snow density of the subnivean space is affected with snowpack deeper than 100 cm, the snow compaction occurs higher in the snowpack and provides a platform above the subnivean space the maximum compression of the subnivean space occurs after 3-5 ski passes, additional use has little additional effect on the subnivean space there seems to be an effect on the subnivean space, resulting in reduction or compaction of the subnivean space and increasing density of the snow beyond the ability of small mammals to utilize it, essentially this provides barriers and can section home ranges to such an extent that it reduces survival rates due to lack of food access, reduced insulation quality, and increased energy use, also, they may have to travel on the surface to bypass these barriers, increasing predation this compaction may benefit some mammals in the short term, reduced transportation energy use for deer, elk, moose, increased range for coyotes, but can also have far reaching, unexpected effects, lynx decline due to opening of habitat to coyote

19. there seems to be an effect on the subnivean space, resulting in reduction or compaction of the subnivean space and increasing density of the snow beyond the ability of small mammals to utilize it, essentially this provides barriers and can section home ranges to such an extent that it reduces survival rates due to lack of food access, reduced insulation quality, and increased energy use, also, they may have to travel on the surface to bypass these barriers, increasing predation sanecki 2006 is one of the few studies on snow compaction effect on small mammals compacted 50 cm deep snowpack and found that subnivean space height decreases from 8-20 cm to 1.2 cm and that densities increased from .35 g/cm3 to .55 g/cm3 also found that detection of 2 small mammal species in the compacted areas decreased 75-80% there seems to be an effect on the subnivean space, resulting in reduction or compaction of the subnivean space and increasing density of the snow beyond the ability of small mammals to utilize it, essentially this provides barriers and can section home ranges to such an extent that it reduces survival rates due to lack of food access, reduced insulation quality, and increased energy use, also, they may have to travel on the surface to bypass these barriers, increasing predation sanecki 2006 is one of the few studies on snow compaction effect on small mammals compacted 50 cm deep snowpack and found that subnivean space height decreases from 8-20 cm to 1.2 cm and that densities increased from .35 g/cm3 to .55 g/cm3 also found that detection of 2 small mammal species in the compacted areas decreased 75-80%

20. lessons for mgmt./planning be aware of impacts on the subnivean space need more winter mammal surveys esp. on home ranges and subnivean use restrict early season travel on shallow snowpack, after 100 cm of snow, less impact on the subnivean space limit travel to designated trails in high use areas (after 3-5 people, same as 100 people) make travel corridors narrower with more tree islands note that presence of vegetation also affects subnivean space (clearing, killing plants) provide tunnels under ski runs, heavily used areas lessons for mgmt./planning be aware of impacts on the subnivean space need more winter mammal surveys esp. on home ranges and subnivean use restrict early season travel on shallow snowpack, after 100 cm of snow, less impact on the subnivean space limit travel to designated trails in high use areas (after 3-5 people, same as 100 people) make travel corridors narrower with more tree islands note that presence of vegetation also affects subnivean space (clearing, killing plants) provide tunnels under ski runs, heavily used areas

24. the subnivean space is incredibly important to the winter ecosystems of alpine and sub-alpine regions, the subnivean space is used by many small mammals (voles, mice, etc.) for insulation and movement through the snowpack to food sources, these animals form the base of the winter food web providing food for predators such as the marten, weasel, coyote, lynx, bobcat, raptors, since the margin for survival is small during winter, even small changes can have a large effect on survival rates and composition small mammals living in and utilizing the subnivean space masked shrew montane shrew southern red-backed vole montane vole deer mouse and other species of mice chipmunks ground squirrels pocket gophers? some bird species others the subnivean space is incredibly important to the winter ecosystems of alpine and sub-alpine regions, the subnivean space is used by many small mammals (voles, mice, etc.) for insulation and movement through the snowpack to food sources, these animals form the base of the winter food web providing food for predators such as the marten, weasel, coyote, lynx, bobcat, raptors, since the margin for survival is small during winter, even small changes can have a large effect on survival rates and composition small mammals living in and utilizing the subnivean space masked shrew montane shrew southern red-backed vole montane vole deer mouse and other species of mice chipmunks ground squirrels pocket gophers? some bird species others