Animal Activity and Tree Well Width

1. Animal Activity and Tree Well Width Erin Kinney Winter Ecology 2011 Mountain Research Station, University of Colorado, Boulder

2. Common Animal Species to be Found Moose Snowshoe Hare Squirrel Vole Weasel Bird Not all species are selected to be out and active during the winter time. The presence of tracks are made by those animals who are physically able to handle the demanding winter cold. Each are adapted with different mechanisms for handling the cold and being able to maneuver in the snow. Animals such as the snow shoe hare are adapted with wider hind feet to redistribute weight for easy transportation on top of the snow. Snow Shoe Hare-front 1 7/8 -3in long and 1 1/8-2 1/4in wide, back 3 ¼-6in long and 1 5/8-5in wide (Murie). The wider chests of moose make it easier for then to travel to higher elevations with deeper snow pack that similar animals like deer could not walk through easily. Found in a study, deer are restricted when snow depth is greater than 40cm, while moose can roam in depths up to 70 cm but experienced difficulty when in ranges of 70-99cm (Kelsall, 1969). Not all species are selected to be out and active during the winter time. The presence of tracks are made by those animals who are physically able to handle the demanding winter cold. Each are adapted with different mechanisms for handling the cold and being able to maneuver in the snow. Animals such as the snow shoe hare are adapted with wider hind feet to redistribute weight for easy transportation on top of the snow. Snow Shoe Hare-front 1 7/8 -3in long and 1 1/8-2 1/4in wide, back 3 ¼-6in long and 1 5/8-5in wide (Murie). The wider chests of moose make it easier for then to travel to higher elevations with deeper snow pack that similar animals like deer could not walk through easily. Found in a study, deer are restricted when snow depth is greater than 40cm, while moose can roam in depths up to 70 cm but experienced difficulty when in ranges of 70-99cm (Kelsall, 1969).

3. Types of Activity Entrance/Exit Holes Resting Tree to Tree Eating The home ranges of animals are looked at as circular when clearly they are not. It is important to think about their actual shape and that the area be calculated on the actual shape rather than a circle. There are several reasons for these animals to be moving around and staying where they are. Scarcity of food, direct or in direct competition, no competition, territorial or compatible species, over or under population(Mohr, 1966). This is going to lead to animals moving around. By looking at their tracks in the snow we are able to tell what they are doing. Subnivean- Small rodents spend most of their time under the snow pack. Vegetation is a large part of why the area is not completely uniform and so in these breaks animals are going to be spending a lot of their time arising to the surface (KORSLUND, 2006). Squirrel-male home range-826ft female-512ft (Mohr,1966) A lot of the time their activity in the winter is going to be focused around trees for food and shelter.The home ranges of animals are looked at as circular when clearly they are not. It is important to think about their actual shape and that the area be calculated on the actual shape rather than a circle. There are several reasons for these animals to be moving around and staying where they are. Scarcity of food, direct or in direct competition, no competition, territorial or compatible species, over or under population(Mohr, 1966). This is going to lead to animals moving around. By looking at their tracks in the snow we are able to tell what they are doing. Subnivean- Small rodents spend most of their time under the snow pack. Vegetation is a large part of why the area is not completely uniform and so in these breaks animals are going to be spending a lot of their time arising to the surface (KORSLUND, 2006). Squirrel-male home range-826ft female-512ft (Mohr,1966) A lot of the time their activity in the winter is going to be focused around trees for food and shelter.

4. Importance of Tree Wells Cover and Protection Heat Transfer Formation Tree Well-area of depression around a tree due to heat transfer and often low hanging branches forming protected air pockets. In a study, tree well size increases with tree height. The effect of conifers to their tree well size is a function of diameter, cover and snow depth. Larger diameter trees tend to have a more gradual sloped well down to the trunk of the tree while smaller diameter trees tend to have a sharper slope down to the trunk. This is due to the amount of snow cover falling off of the tree’s branches(Strum,1992). Low hanging branches create a sheltered environment where heat and air pockets form a well. Tree wells give a somewhat protected area for when subnivean creatures when they may run into them and choose to come to the surface. Other larger mobile and active animals, like the snowshoe hare, will choose a protected cover area to take their time to rest (KORSLUND, 2006). Factors such as size of tree well, amount of cover and snow depth may influence where thee animals are choosing to spend their time.Tree Well-area of depression around a tree due to heat transfer and often low hanging branches forming protected air pockets. In a study, tree well size increases with tree height. The effect of conifers to their tree well size is a function of diameter, cover and snow depth. Larger diameter trees tend to have a more gradual sloped well down to the trunk of the tree while smaller diameter trees tend to have a sharper slope down to the trunk. This is due to the amount of snow cover falling off of the tree’s branches(Strum,1992). Low hanging branches create a sheltered environment where heat and air pockets form a well. Tree wells give a somewhat protected area for when subnivean creatures when they may run into them and choose to come to the surface. Other larger mobile and active animals, like the snowshoe hare, will choose a protected cover area to take their time to rest (KORSLUND, 2006). Factors such as size of tree well, amount of cover and snow depth may influence where thee animals are choosing to spend their time.

5. What is the Correlation to Animal Activity and Tree Well Size and Quality? Question By Quality I mean coverQuestion By Quality I mean cover

6. Methods Field Observations going from tree well to tree well, activity under tree, resting area, entrance/exit hole Measurements width of tree well, area of track, area of hole Observations-Walking around in the woods on two different occasions Measurements- Using a ruler and snow depth probe, taking measurements of distance from tree trunk to edge of snow, amount of cover provided, type of activity, observations Classification-Tree to Tree, Resting, Holes, Area of Animal Track Graphs- Cover to no cover, Animal area of track vs Tree well size Pearson Product-a measure of correlation between two variables, giving a value between -1 and 1, measures the strength of linear dependence between the two variables, A value of 1 implies that a linear equation describes the relationship between X and Y perfectly, -1 means that as Y decreases X increases, 0 means no correlation Limitations-poor weather conditions for seeing tracks, not enough data points, identification Results-Classified animal tracks by their areaObservations-Walking around in the woods on two different occasions Measurements- Using a ruler and snow depth probe, taking measurements of distance from tree trunk to edge of snow, amount of cover provided, type of activity, observations Classification-Tree to Tree, Resting, Holes, Area of Animal Track Graphs- Cover to no cover, Animal area of track vs Tree well size Pearson Product-a measure of correlation between two variables, giving a value between -1 and 1, measures the strength of linear dependence between the two variables, A value of 1 implies that a linear equation describes the relationship between X and Y perfectly, -1 means that as Y decreases X increases, 0 means no correlation Limitations-poor weather conditions for seeing tracks, not enough data points, identification Results-Classified animal tracks by their area

7. Methods Data Analysis Classification 3 categories (tree to tree, hole, resting) Comparative Graphs track or hole area vs well width average track or hole area with and without cover Pearson product-moment correlation coefficient range of -1 to 1 Limitations weather, snow fall Observations-Walking around in the woods on two different occasions Measurements- Using a ruler and snow depth probe, taking measurements of distance from tree trunk to edge of snow, amount of cover provided, type of activity, observations Classification-Tree to Tree, Resting, Holes, Area of Animal Track Graphs- Cover to no cover, Animal area of track vs Tree well size Pearson Product-a measure of correlation between two variables, giving a value between -1 and 1, measures the strength of linear dependence between the two variables, A value of 1 implies that a linear equation describes the relationship between X and Y perfectly, -1 means that as Y decreases X increases, 0 means no correlation Limitations-poor weather conditions for seeing tracks, not enough data points, identification Results-Classified animal tracks by their areaObservations-Walking around in the woods on two different occasions Measurements- Using a ruler and snow depth probe, taking measurements of distance from tree trunk to edge of snow, amount of cover provided, type of activity, observations Classification-Tree to Tree, Resting, Holes, Area of Animal Track Graphs- Cover to no cover, Animal area of track vs Tree well size Pearson Product-a measure of correlation between two variables, giving a value between -1 and 1, measures the strength of linear dependence between the two variables, A value of 1 implies that a linear equation describes the relationship between X and Y perfectly, -1 means that as Y decreases X increases, 0 means no correlation Limitations-poor weather conditions for seeing tracks, not enough data points, identification Results-Classified animal tracks by their area

8. Entrance/Exit Holes No correlation between animal area and tree well width Medium size holes around large trees Most Holes in general were around the smaller trees No correlation between animal area and tree well width Medium size holes around large trees Most Holes in general were around the smaller trees

9. Entrance/Exit Holes Small correlation that frequency of holes is related to cover Larger holes tend to not have cover Small correlation that frequency of holes is related to cover Larger holes tend to not have cover

10. Resting Areas Large Correlation That the larger your area the smaller your tree well Small sample size Mostly includes mooseLarge Correlation That the larger your area the smaller your tree well Small sample size Mostly includes moose

11. Resting Areas Large correlation-the larger you are the less you prefer cover Small sample size Mostly just mooseLarge correlation-the larger you are the less you prefer cover Small sample size Mostly just moose

12. Tree to Tree No Correlation between animal area and tree well widthNo Correlation between animal area and tree well width

13. Tree to Tree Medium correlation, the smaller you are the more you prefer cover.Medium correlation, the smaller you are the more you prefer cover.

14. Discussion Cover Tree Well Size Area of Tracks Area of Holes Areas of Improvement and New Study Cover-There was a correlation for a preference to cover, especially for smaller area tracks. This could be due to vulnerability in a decreasing size animal. Tree Well Size-There was mostly no correlation, only in resting area with a small sample size. Though tree well size can vary, they are not the main reason for animals to go to a tree for protection based on well size. Area of Tracks-They are a good way to generalize smaller animals, but when looking at resting areas they should be classified differently. Area of Holes-Sometimes there are more than one hole which shows a large amount of activity in a single tree well. Future - Follow one specie, follow one animal, or look into burrows inside of tree wells compare to burrows away from tree wells. I tried to look at correlations between well size and activity and didn’t find one but there does seem to be a correlation between smaller animals and a preference of cover for the trees they do stay near. By knowing that tree well width does not effect where animals are spending their time we can start to focus more on studies of habitat cover and why they are spending their time there. Cover-There was a correlation for a preference to cover, especially for smaller area tracks. This could be due to vulnerability in a decreasing size animal. Tree Well Size-There was mostly no correlation, only in resting area with a small sample size. Though tree well size can vary, they are not the main reason for animals to go to a tree for protection based on well size. Area of Tracks-They are a good way to generalize smaller animals, but when looking at resting areas they should be classified differently. Area of Holes-Sometimes there are more than one hole which shows a large amount of activity in a single tree well. Future - Follow one specie, follow one animal, or look into burrows inside of tree wells compare to burrows away from tree wells. I tried to look at correlations between well size and activity and didn’t find one but there does seem to be a correlation between smaller animals and a preference of cover for the trees they do stay near. By knowing that tree well width does not effect where animals are spending their time we can start to focus more on studies of habitat cover and why they are spending their time there.

15. Conclusions Animals out in Winter Specializations, Limitations, Active Tree Wells Formation, Cover and Protection Methods Observations, Measurements, Data Analysis, Pearson Product -1 to 1 Animals to Tree Well Size No Correlation Animals to Amount of Cover Correlation Select animals out in winter time have adaptations that allow them to be there. They are limited by many factors, such as scarcity of food, direct or in direct competition, no competition, territorial or compatible species, over or under population. Tree wells are related in size to the diameter of the trunk they form around. They are what keeps the subnivean area uniform and can provide a covered and protected habitat. This experiment was done on observations and data measurements. Analysis form excel spreadsheets, using graphs and the Pearson Product. Animal to tree well size had no correlation, but on some we could see a little bit of a trend for smaller animal entrance/exit holes preferring smaller trees. There was a correlation of animals preferring trees with cover, There was little data for the resting areas but it was starting to suggest that the larger animals, like moose choose no cover. Further study can look into what these animals are doing in these covered areas? Eating this mushroom? Select animals out in winter time have adaptations that allow them to be there. They are limited by many factors, such as scarcity of food, direct or in direct competition, no competition, territorial or compatible species, over or under population. Tree wells are related in size to the diameter of the trunk they form around. They are what keeps the subnivean area uniform and can provide a covered and protected habitat. This experiment was done on observations and data measurements. Analysis form excel spreadsheets, using graphs and the Pearson Product. Animal to tree well size had no correlation, but on some we could see a little bit of a trend for smaller animal entrance/exit holes preferring smaller trees. There was a correlation of animals preferring trees with cover, There was little data for the resting areas but it was starting to suggest that the larger animals, like moose choose no cover. Further study can look into what these animals are doing in these covered areas? Eating this mushroom?

16. References Kelsall, John. "Structural Adaptations of Moose and Deer for Snow." Journal of Mammology. 50.2 (1969): 302-310. KORSLUND, L. and STEEN, H. “ Small rodent winter survival: snow conditions limit access to food resources.” Journal of Animal Ecology(2006): 75: 156–166. Mohr, Carl, and William Stumpf. "Comparison of Methods for Calculating Areas of Animal Activity." Journal of Wildlife Management. 30.2 (1966): 293-304. Murie, Olaus Johan. "A Field Guide to Animal Tracks." Google Books. Web. 18 Feb. 2011. http://books.google.com/books?hl=en&lr=&id=BwVw6YpLyDkC&oi=fnd&pg=PT13&dq=animal tracks&ots=15OgSGjc2A&sig=KaxjItEV4X1OCi2TsNoEYFnDUnE#v=onepage&q&f=false. Strum, Matt. "Snow Distribution and Heat Flow in the Taiga." Arctic and Alpine Research. 24.2 (1992): 145-152.