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In the summer of 2000, I had the opportunity to spend three weeks
camping and performing fieldwork in the Cloud Peak Wilderness Area of the Bighorn Mountains of Wyoming. Accompanying me
were 16 of my fellow students from State College Area High School in Pennsylvania, as well as 17 students from James
Gillespie High School in Edinburgh, Scotland (Figure 1). The purpose of the expedition, organized and headed by State
College Area High earth science teacher Dr. Thomas Arnold and Edinburgh geography teacher Mr. George Meldrum, was to
conduct various studies of the region, including a heat-budget determination, a lake water analysis, and a mapping of
the valley. My research focused on the vegetation and small mammals present in the riparian area of Oliver Creek. As a
member of the "Bio Group" (Figure 2), I studied the changes in vegetation with increasing distance from the stream
across three habitats, and determined the types and diversity of small mammals present in those three habitats.
Additionally, I collected and analyzed soil samples in the three habitats, monitored air conditions, and determined the
types of macroinvertebrates found in Oliver Creek. The Bio Group was assisted in these tasks by field biologist Julie
Roth, a graduate student at the University of Nevada. This expedition provided me with a unique opportunity to directly
study the biology of a wilderness area while interacting with a diverse and international group of students who are as
interested in science as I am. Furthermore, since I had never gone camping before, this research endeavor meant that I
also had to meet the challenges of learning to properly pitch a tent, sleep on the hard ground, and prepare meals on an
outdoor cookstove.
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We set up base camp at the Hettinger Rest Area in the Bighorn National
Forest near Buffalo, Wyoming. Our research site, located at an elevation of 8,750 feet in the Cloud Peak Wilderness
Area, was about a 10-minute drive away, followed by a 2.5-mile uphill climb from the main campsite (Figures 3 and 4).
Each morning, regardless of what day of the week it was or what the weather was like, we trudged up the mountain at nine
in the morning and returned either at 4 pm or 6:30 pm, depending on the research conducted on that day. The sound of
banging pots and pans roused us from our slumbers every morning no later than 7 am. Breakfast was always the same:
oatmeal. While we tried to spice it up with brown sugar, raisins, or honey, it always had the same thick and bland
taste. The first few days of our expedition were somewhat bleak; it rained every day. It was so cold that we went to
sleep wearing multiple layers of clothes. The Scots were delayed in their arrival, and we were trying to comprehend the
reality of eating oatmeal every day for the next three weeks. However, once the days became sunnier and everyone arrived
so that we could begin our research, we began to enjoy the trip immensely. Everyone in my group joined in the excitement
of actually holding a chipmunk prior to weighing it, or finally locating an unknown forb in a field guide. In the
evenings, we all gathered around the campfire and shared our discoveries as well as our misfortunes.
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The first part of the Bio Group's research dealt with the vegetation
of the Oliver Creek drainage basin (Figure 5). The study site consisted of meadowland and a recovering burn area on the
north side of Oliver Creek, and forested land on the creek's south side. To determine how the vegetation changed with
increasing distance from the stream, a straight-line transect was set up perpendicular to the eastwardly-flowing creek.
This transect began at 44°16'19"N, 107°00'46"W on the north side of the stream and at 44°16'19"N, 107°00'45"W on the
stream's south side. White flags were positioned every 10m from the stream along the transect, for 150m on the creek's
north side and for 110m on the creek's south side (Figure 6). The meadow extended for a distance of about 60m, while the
remaining land on the north side was an area experiencing regrowth after a 1988 burn event. Mature forest was found on
the south side of the creek. At each white flag, we laid out a 1m2 vegetation sampling quadrat, using meter sticks.
Within each quadrat, the percentage of cover was determined by means of the point-intercept method of using knitting
needles on a meter stick frame (Elzinga). Vegetative species present were identified using guides such as Earl Jensen's
Flowers of Wyoming's Big Horn Mountains and Big Horn Basin and Classification of Riparian Communities on the Bighorn
National Forest, published by the USDA Forest Service. It was interesting to look at the Western vegetation, which
differed from what I was used to seeing in Pennsylvania. Although I am well acquainted with many Eastern species of
trees, shrubs, and plants, I encountered many plants, such as pussytoes (Antennaria), with which I was not familiar.
Figures 7 and 8 show two of the plants that grew next to Oliver Creek, lupine (Lupinus) and sedge (Carex).
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The second focus of our research efforts was a determination of the
types and diversity of small mammals present in each habitat. This aspect of our studies was the most fun, since we got
to hold the mammals in order to weigh and measure them (Figure 9). (Note that all of the mammals were safely released
after trapping.) To conduct this part of the study, small-mammal trapping grids were set up in the same three habitats
in which the vegetation transect was laid out. We did not place the trapping grids exactly along the vegetation
transect, since our movements in assessing the vegetation could have distracted the mammals. Consequently, the mammal
trapping grids were set up in different representative areas of the habitats. Each trapping grid consisted of 30 traps
spaced 10m apart. The burn area and forest trapping grids were set up as 5x6 sampling rectangles, while the meadow was
set up as a 4x7 trapping grid, with the two remaining traps positioned as extensions of the middle rows. Bait made of
peanut butter and oats was placed in each of the aluminum traps; cotton wool was also added to keep the mammals warm in
case of overnight capture. The traps were then covered with litter and brush to disguise them and to provide insulation
against temperature extremes (Figure 10). The small mammals that we caught were carefully handled while they were
measured for mass, total length, tail length, ear length, and hind foot length (Figure 11). Gender and reproductive
condition were also noted. The animals that were captured were marked in case they were trapped again. We placed nail
polish markings on their ears and also clipped a small amount of hair from a particular location that was noted on the
data chart. We checked the traps twice daily -- at approximately 10 am and again at about 5 pm, each time resetting them
for the next trapping session. The vegetation work was done in the afternoon between trap checks. Because of our long
trapping day, the biology group stayed overnight at our high camp on the mountain in order to be able to check the traps
on time in the morning on the five days that mammal counts were made.
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In addition to the main vegetation and small mammal studies, soil
samples were collected in the three habitats, temperature variations of the air were monitored, and a macroinvertebrate
sampling of the creek was performed. The purpose of the soil sampling was to provide a better idea of the conditions in
which the vegetation grew. Soil sampling was performed at each of the vegetation quadrats. On-site measurements included
soil moisture content, pH, and infiltration rates. Collected soil samples were sent for further analysis for
conductivity and phosphorus, potassium, and magnesium content to Pennsylvania State University. The thermistor study was
set up to provide hourly air-temperature monitoring of the valley. Five thermistor poles were set up on the north side
of Oliver Creek at 30m intervals along the vegetation transect (Figure 12). Each pole had six probes, placed at 1m
intervals, from ground level to a height of 5m. Temperature readings were recorded hourly over a three-day study period.
Since we were working in a riparian zone, we identified the macroinvertebrates present at three stream locations -- a
riffle, a run, and a pool just downstream of our vegetation transect -- and calculated the Pollution Tolerance Index (PTI)
for each location (Figure 13). As the stream's substrate was made up of various-sized boulders and cobbles, 20 rocks
were selected for examination at each location, and the number and type of macroinvertebrates present were recorded. The
average rock circumferences and lengths were also measured.
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The data that we obtained during our expedition is presented in the
accompanying graphs and tables. Figures 14A and 14B show the percent coverage of the three habitats by plants, litter,
wood debris, rock, bare ground, and animal waste in relation to distance from Oliver Creek. Figures 15A and 15B are kite
diagrams that break down the plant cover into forbs, grasses, sedges, shrubs, mosses and lichens, and conifers, while
the specific types of plants found and their frequency of occurrence are listed in Table 1 (tables included at the end
of the essay). Frequency of occurrence is obtained by dividing the number of quadrats that a plant occurs in by the
total number of quadrats in a particular habitat -- seven in the meadow, nine in the burn area, and 12 in the forested
area -- and then multiplying by 100%. Note that the vegetation quadrats did not include large-diameter trees in order to
get a representative picture of the non-canopy vegetation in the forested and burn areas. An indication of the size of
the trees in the wooded areas is given by Figure 16, which shows the mean circumference of the five closest trees within
3m of the vegetation quadrats. There were no notable trees in the meadow; although willows were found, they were so
small that they were designated as shrubs. The burn area showed the greatest plant-species richness, with 80% of the
observed types located there. The meadow had the lowest richness, with only 12 of the 30 observed types of plants.
Plants common to all three areas included heartleaved arnica (Arnica cordifolia), fireweed (Epilobium angustifolium),
grasses (Poa), and mosses. The majority of the quadrats on the north side of the stream (meadow/burn area) exhibited 50%
or higher plant cover, while only five of the 12 studied quadrats on the forested south side showed a percentage plant
cover greater than 50%.
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Seven different species of mammals were captured during a five-day
study period, as shown in Figure 17. Least chipmunks (Tamius minimus confines) were the dominant species in the burn
area and forest, while meadow voles (Microtus pennsylvanicus insperatus) were the most frequently caught species in the
meadow. Table 2 lists the number of small mammal captures that occurred overnight and during the day in each of the
three habitats. Both new captures (bold type) and recaptures (parentheses) are listed. The burn area had the highest
number of small mammals caught, but the lowest richness, since only chipmunks were captured. The forest showed the
greatest species richness, with five types of mammals captured. There appears to be no direct correlation between plant
and small-mammal species richness, as indicated in Figure 18. The burn area, which exhibited the greatest plant-species
richness, also had the lowest small-mammal species richness. Only two small mammal species were captured in more than
one habitat; least chipmunks in all three habitats and the red squirrel (Tamusciurus hudsonicus baileyi) in the forest
and the meadow. Five of the seven observed species limited themselves to one environment. Use of the Simpson diversity
index, Ds =1-Spi2, where pi is the relative species abundance, to compare the small mammal communities in the three
habitats yielded values of Ds(burn)=0, Ds(meadow)=0.66, and Ds(forest)=0.65. The diversity indices of the meadow and
forest are very comparable and are greater than that of the burn area, in which only one small mammal species was found.
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The soil was acidic throughout the entire riparian zone, as indicated
by the graph in Figure 19, with the least acidic soil found in the burn area. Mean values of pH increased from 4.8 in
the forested area to 5.0 in the meadow to 5.7 in the burn area. As shown in Tables 3A and 3B, the soil analysis by the
Agricultural Analytical Services Laboratory at Pennsylvania State University indicated that the meadow had the lowest
soil-nutrient levels, with only magnesium in the optimum plant-growth zone. Highest nutrient levels were found in the
burn area, with the amounts of potassium and magnesium present increasing significantly at the meadow/burn area
transition.
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As is seen in Figure 20, the region experienced measurable levels of
precipitation only during the first part of the study; there was negligible precipitation after June 30. Since the small
mammal study began on June 29, on which only 0.3 mm of rain fell, rainfall was not a factor in the capture rate. Figure
21 gives the air temperature results at ground level and at 5m from two thermistor poles located 120m apart, one placed
in the meadow and the other in the burn area. The results indicate that the air at ground level in the meadow exhibited
greater variations in temperature than did the air next to the ground in the burn area. At higher air column levels,
both the meadow and the burn area showed comparable fluctuations in air temperature over a 24-hour time period as well
as a smaller level of variation than that which occurred in the air closer to the ground.
The quality of the water in Oliver Creek was assessed using the 22 specific-indicator organisms of the Pollution
Tolerance Index (PTI). Table 4 lists the indicator macroinvertebrates that were found in the three study areas.
Classification of the macroinvertebrates present in a riffle, run, and pool yielded cumulative index values of 20, 15,
and 15, respectively. PTI values between 17 and 22 indicate good water quality, while numbers in the range 1116 suggest
fair water quality.
Much still remains to be done in order to finish the analysis of the data that were collected on the expedition, and not
all of it, such as the data on the small mammals' weight and size and soil infiltration rates, have been included in
this essay. Additional statistical relationships need to be determined, comparisons between data acquired on this
expedition and that obtained on any previous studies of the area and cited in the literature must be made, and study
techniques and methods must be examined for deficiencies. A follow-up expedition to the area would be especially useful,
particularly to see how the regrowth in the burn area has progressed.
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Even if my research efforts do not produce a significant scientific
contribution, my Wyoming expedition was a success. It provided me with an amazing opportunity to learn how fieldwork is
actually conducted, to spend time in the wilderness examining and marveling at the natural world, and to interact with
people from another continent whom I had never met before but who had the common bond of a love of science. This trip
held a lot of "firsts" for me: my first time camping, my first time holding a chipmunk, my first time going to the
bathroom in the woods. I had to carefully measure distances for the vegetation quadrats, set up the 5m thermistor poles,
carry traps up the side of a mountain, and make sure that I correctly recorded my findings. Although the trip was
serious while we were working, we also had time to have fun. I am left with many memories of the expedition. I remember
the first day we spent with the Scots, and how we marveled over how they supposedly spoke the same language as we did
yet used so many foreign words. Their use of "trainers" for sneakers, "minging" for disgusting, and "Philadelphia" for
any type of cream cheese, prompted us to put together a Scottish-American dictionary. I remember spending the Fourth of
July at an artists' residency, playing volleyball, eating at "Aunt Bea's Chuckwagon" (Figure 22), and watching fireworks
light up the night sky. I remember stumbling out of the tent at high camp at four in the morning to take a thermistor
reading and sitting in the hot afternoon sun determining sedge cover. I remember my first sighting of a moose along
Oliver Creek and looking up into the clear Wyoming night sky to find Cassiopeia and Cygnus. I remember 34 students
sitting around a campfire making s'mores and the way we slowly dismantled the camp on our last day in Wyoming. The three
weeks that I spent in the mountains of Wyoming doing research as part of a scientific expedition allowed me to learn
more about our wilderness areas while interacting with a diverse group of people. This experience led me to the
realization that I want to discover more about the natural world and go on many more scientific expeditions.
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References
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Craighead, John, Frank Craighead, Jr., and Ray Davis. A Field Guide to Rocky Mountain Wildflowers. New York: Houghton Mifflin Co., 1963.
Despain, Don G. "Vegetation of the Big Horn Mountains, Wyoming, in Relation to Substrate and Climate." Ecological Monographs 43.3 (1973): 329355.
Elzinga, Caryl, Daniel Salzer, and John Willoughby. Measuring and Monitoring Plant Populations. USDI Bureau of Land Management, BLM/RS/ST-98/005+1730, 1998.
Girard, Michele, David Wheeler, and Stephanie Mills. Classification of Riparian Communities on the Bighorn National Forest, USDA Forest Service, R2-RR-97-02, 1997.
Jensen, Earl R. Flowers of Wyoming's Big Horn Mountains and Big Horn Basin. Greybull, Wyoming: Chimney Rock Books, 1987.
Lofgren, Lawrence. "Alpine Flowering Plants of the Cloud Peak-Cliff Lake Area, Big Horn County, Wyoming." M.S. Thesis. Laramie, Wyoming: University of Wyoming, 1956.
McComb, William C., Carol L. Chambers, and Michael Newton. "Small Mammal and Amphibian Communities and Habitat Associations in Red Alder Stands, Central Oregon Coast Range." Forest Research Laboratory. Res. Pap. 2762. Corvallis, Oregon: Oregon State University, 1992.
Mitchell, Mark and William Stapp. Field Manual for Water Quality Monitoring. 11th ed. Dubuque, Iowa: Kendall/Hunt Publishing Co., 1997.
Wilson, Don, F., Russell Cole, James Nichols, R. Rudran, and Mercedes Foster, eds. Measuring and Monitoring Biological Diversity: Standard Methods for Mammals. Washington: Smithsonian Institution Press, 1996.
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