Effects of Rock Climbing on Vegetation and Invasive Species at Devils Lake,
Wisconsin
By
Charles Clement Hoover
An Undergraduate Thesis
Submitted in Partial Fulfillment for the Requirements of
Bachelor of Arts
In
Geography and Earth Science
Carthage College
Kenosha, WI
May, 2011
Table of Contents
Section
Page #
Introduction
Page 2
Literature Review
History of Recreational Management
Rock Climbing
Invasion and Disturbance
Environmental Impacts of Climbing
Page 3
Page 3
Page 4
Page 5
Page 7
Location
Devils Lake
Page 9
Page 9
Methods
Field Sampling
Satellite Imagery Methods
Lab Methods
Statistical Methods
Page 12
Page 12
Page 14
Page 16
Page 16
Results
Field Results
Satellite Imagery Results
Page 17
Page 17
Page 21
Discussion
Page 23
Work Cited
Page 26
1
List of Figures
Figure 1.
Page 9
Figure 2.
Page 10
Figure 3.
Page 11
Figure 4.
Page 13
Figure 5.
Page 13
Figure 6.
Page 15
Figure 7
Page 15
Figure 8.
Page 17
Figure 9.
Page 21
Figure 10.
Page 22
Figure 11.
Page 22
2
List of Tables
Table 1.
Page18
Table 2.
Page 19
Table 3.
Page 20
3
Effects of rock climbing on vegetation and invasive species at Devils Lake, Wisconsin
Charles Clement Hoover
_________________________________________________
Abstract
Since the passing of the Wilderness Act in 1964 participation in outdoor recreation has
risen to six times more participants. Rock climbing is a fairly new recreational activity
taking hold in the 1920’s. The two main aspects of climbing include the approach and the
climb that consequently affect vegetation on and leading up to the climb. This study was
conducted at Devils Lake in Merrimac Wisconsin. 10 x 10 m plots were set on the top
and bottom of two high use routes and two low use routes. At each plot species diversity,
percentage cover, species, soil texture, and soil pH where all recorded. Satellite imagery
was also used to view the vegetation surrounding the cliffs. The data collected showed
differences between the high use routes and the low use routes and the top of routes vs.
the bottom of routes in species diversity. With proper management the impact from
recreation and climbing can be greatly reduced if the proper rules and regulations are set
in place.
_________________________________________________
Introduction
Outdoor recreation is a major part of the 20th century lifestyle; it has grown
continually since the Wilderness Act in 1964. This increase in the recreationist
population has inadvertently caused environmental impacts and disturbances on delicate
ecosystems. These anthropogenic disturbances disrupt erosion, succession, and
biodiversity by placing added stress on the environment. Humans are also used as a
vector of transport by invasive species to reach isolated areas. Rock climbing is a fairly
new and growing recreational activity, gaining popularity in the 1920’s and growing
considerably from there. Rock climbing is traditionally considered to be one of the more
environmentally friendly outdoor recreations; however, the increase in popularity has
begun to impact erosion, succession, and biodiversity. Studies have previously been
conducted on the effects of rock climbing on vegetation, but little is still known. Many
recreational areas are being opened to climbers, bringing along these anthropogenic
disturbances and invasive species, such as at the popular climbing area Devils Lake,
located in Merrimac Wisconsin and has many climbing routes. These routes differ in
popularity among climbers due to accessibility and difficulty. Differences are then caused
4
from the amount of which they are climbed. Consequently rock climbers have the
capacity to impact surrounding vegetation of the climbing area.
Literature Review
History of Recreational Management
The recreational use of the National Wilderness preservation has escalated to six
times its original use since the Wilderness Act in 1964 (Cole 1996). Between 1980 and
1990 the number of individuals taking part in non-consumptive outdoor recreation almost
doubled (U.S. Department of the Interior, Fish and Wildlife Service and U.S. Department
of Commerce, Bureau of the Census 1993). Though individually these activities can be
low-impact, this increase in recreational activity has inadvertently over time begun to
impact the environment. The increase in activity and impact has pushed ideas such as the
Leave No Trace principals. These principals such as being prepared, using sturdy
surfaces, dispose of waste properly, leave what you find, properly use campfires, respect
wild life, and respecting other visitors have helped minimize impact. “Leave No Trace”
principles are based on guided principals for minimizing the impact of outdoor recreation
helping to reduce anthropogenic disturbance on natural systems (Borrie and Harding
2002). However the impact is still high, and attempts have been made to educate
recreationists encouraging respect for the regulations aiming to reduce degradation
(Borrie and Harding 2002). The introduction of social morals such as Leave No Trace is
thought to be enough to make recreationists aware of their impact (Borrie and Harding
2002). A study conducted by Borrie and Harding (2002) in the Bitterroot Valley in
Montana showed that there are social factors that come into play when making lowimpact leave no trace decisions. Four cognitive social factors impacted the individuals
decisions (1) comprehending the situation and identifying the needs for low-impact
practices, (2) retrieving the possible behavior options from memory, (3) judging which
behaviors are most appropriate, and (4) deciding which behavior to carry out. In this
study three informational posters were placed at three different main trailheads to inform
climbers on impact, compliance, and ethics. Climbers were then given a survey
answering questions on social aspects of climbing, including where they learned how to
climb, their experience in the area, attitudes toward environmental impacts, and attitudes
5
toward placing new route and climbing near Native American artifacts. The results show
that climbers who began climbing outdoors where more comfortable placing new routes
and using power drills to place equipment. This study also found that placing bulletins
and alerts at trailheads is ineffective in changing visitor behavior, but may reinforce
previous morals. These studies show that recreationists can correctly answer questions
about low-impact behaviors, though they may not be actually carrying out those
behaviors (Stubbs 1991). Ignoring low-impact behavior is placing an unnatural stress and
disturbance on the environment.
Rock Climbing
There are many forms of climbing including traditional climbing, sport climbing,
bouldering, aid climbing, mountaineering, and free soloing. Each is unique and requires
different protection and equipment that can effect the environment in different ways. The
different protection and equipment is used for the safety of the climber, to avoid serious
injury or even death. Traditional climbing uses protection called nuts and cams coming in
various sizes, allowing them to be placed in different sized cracks and fissures within the
rock. The climber then clips his/her rope into the nut or cam, which uses the friction of
the device against the rock to catch a fall. Sport climbing is less technical than traditional
climbing using quick draws to clip the rope into previously bolted routes. This form of
climbing adds a degree of safety because of the previously bolted routs, making it one of
the most popular. Bouldering is considered the simplest form of climbing, usually not
occurring over 15 feet, the required equipment is a “crash pad” which cushions the fall
and allows for a safe landing (Reid 1998). Aid climbing also depends on the use of bolts;
the climber depends completely on ascenders to progress upward. The most natural but
most dangerous form of climbing is free climbing; this method is completely protection
free, making it a very uncommon form of climbing.
6
Climbing has changed considerably from its origins, new technology has allowed
climbing becoming less intrusive and less damaging to the rock and the environment.
Many factors such as accidents, marketing, demographics, climbing developments,
developments in related sports, research, assorted climbing organizations, and
government regulations, have forced the evolution of climbing gear and equipment
(Custer 2007). These factors pushed for new technology that meet regulations and
increased research to reduced equipment failure. There are two forms of protection that
have been developed, active protection and passive protection. Active protection (cams)
have moving spring loaded parts, Passive protection (Slings, Hexes, Nuts, and Tricame)
are solid with no moving parts. These are both used in multiple forms of climbing. The
protection is placed in spaces to hold the rope should a climber fall. Stuck protection is
just left in the rock bringing down the aesthetics of the environment. Many times a
weighted fall will break the rock or become stuck. This can permanently alter the rock
disturbing the natural environment. Various species can be influenced by alterations
caused by climbers.
Invasion and Disturbances
Isolation drives the development of new species. Allopatric speciation occurs
through geographic isolation, such as the dividing of one species by a physical feature,
such as mountains, and rivers creating barriers (Huggett 1998). These barriers drive
diversity within the environment; occasionally they are naturally crossed through forms
of migration. Since humans first began their process of dispersion, through migration
they have helped species cross these geographic boundaries more readily. Non-native
species have used humans as a vector of transport via clothes, boats, cars, and shoes ex.
Using humans as a transport has allowed non-native species to reach areas unavailable by
traditional transport mechanisms. These new invasive species threaten the original
biodiversity of an ecosystem, directly altering and affecting the health of that
environment (Lockwood et al. 2007). These non-domestic species threaten the wellbeing
of many ecosystems, causing them to lose their complexity, simplifying the interactions
between species, alter nutrient cycling, and disrupting important processes such as
succession (Elton 1958).
7
Succession is an important process in the development of new plant communities
altering them over time. The two forms of succession, primary and secondary, both occur
after different degrees of disturbance. The process starts with pioneer species (mosses
and Lichens) altering the environment to fit their needs; withdrawing nutrients from rock
and soil for growth. The alterations made by the pioneer species allow for further
colonization by the intermediate species, this stage is highly competitive for space,
nutrients, and light. Finally the climax species are the last to arrive, bringing stability and
balance to the community (Huggett 1998).
Non-native species can disrupt succession and diversity by out competing native
species during these important stages. Many invasive species lack natural predators in
their invaded environment (Elton 2000), allowing them to out compete domestic species.
When resources are low due to over competition from invasive species it makes it much
more difficult for native species to take hold. Ecosystems are designed to adapt to natural
disturbance and to stress placed on the environment from environmental factors such as
freeze thaw, heavy rain, natural erosion, and falling rocks.
The non-native stress and disturbance coming from overuse, erosion, soil
compaction, cleared trails, and other manipulations of an area put greater stress on the
environment. Recreational sports such as hiking and camping have been around for
centuries, continually placing non-native stresses on the environment. The disturbances
caused by recreation alter natural systems leading to losses in energy through destruction
and negative influences on wildlife deterring the natural habitat (Taylor and Knight
2003). In the 1920’s rock climbing started to become a very popular recreational sport in
the United States (Morva). The continual growth and popularity of rock climbing has
created another unnatural stress and disturbance on the environment. Researching the
reactions of ecosystems to disturbances from human activities can help understand the
impact of specific activities, knowing these impacts can lead to rules and regulations that
preserve these natural systems (Taylor and Knight 2003). According to a study conducted
by Knight, the impact of outdoor recreation disrupts wildlife, results in energy costs,
influences the behavior and fitness of animals, and causes avoidance of humans within
the habitat (2003). All animal species researched (mule deer, bison, and pronghorn)
demonstrated a 70% probability be to be driven 100m off a given trail. This study also
8
included the recreationist perception of recreational impacts on wildlife, of 640
backcountry travelers 50% of them believed outdoor recreation had no effect on wildlife
and the environment (Taylor and Knight 2003). Not much is known about the impact of
recreational rock climbing, compared to the more traditional recreation activities such as
hiking (Taylor and Knight 2003). As a result climbing has the potential to the
environment surrounding the climbing route.
Environmental Impacts of Climbing
Climbing has many aspects that can place stress and disturbance on the
environment and vegetation. The approach of a climb is one of the most important
aspects of a climb because it gets you to your route and because there is somewhat of a
mental preparation done during the approach. However important, the approach can
cause a great deal of stress on the environment. Often from increased use of climbing
areas the approach is made easy by packed trails. Some areas have become so compact it
has caused major erosion, ruining the landscape (Genetti and Zenone 1987). Genetti and
Zenone found that within Pinnacles National Monument, Monterey, and San Benito
Counties fourteen percent of the climbed areas studied had trail depth of 78 cm or more,
with two being 128 cm. Many times the increased traffic along with the absence of
designated trails climbers create a maze of unnatural trails leading to the climbing areas,
disturbing the vegetation and increasing erosion (Genetti and Zenone 1987). There are
many other factors that can effect the erosion of these trails other than use frequency. The
grade of the area, vegetation type, soil type, and soil depth can cause differences in
erosion. The study done in Pinnacles National Monument, Monterey, and San Benito
Counties, California also found that a flat trail receiving twice as much use as the others
had far less erosion, then the areas with steepness grades of at least 35 percent (Genetti
and Zenone 1987). Of the studied sites 32% of them had “substantial to severe “ impact
and 68% had “no to moderate” impact, the majority of the impact was to the vegetation in
the areas through direct damage from climbers or from erosion caused by climbing trails.
It is not evident the role that vegetation plays in the process of erosion, but it is known
that the removal of vegetation has a major influence on erosion (Genetti and Zenone
1987).
9
Along with the effects from erosion climbing is believed to directly effect
vegetation, however little is known about the actual impacts of climbing (Rusterholz,
Muller, & Baur 2004). However a study conducted by Nuzzo, examined the effects of
rock climbing on cliff goldenrod in the Mississippi Palisades State Park on the cliff banks
of the Mississippi River. The data collected from climbing routes that have been
continually used since the 1940’s. At the top of each route, eleven 1-m wide belt transects
were established at the top of actual routes on the cliff face. This study found that rock
climbing has a significant effect on cliff goldenrod; with a decrease in both fertile and
sterile plants the density was greatly reduced (Nuzzo 1995). When climbing a new or
unused route, climbers generally “clean the route,” removing vegetation and debris. This
directly affects the delicate ecosystems which are not exposed to frequent disturbance
(Kuntz & Larson 2005). If a system is not adapted to dealing with such disturbances,
having a low level of resilience after a large disturbance. Studying the effects of climbing
is still a fairly recent area of study, so there is still much to be learned (Genetti and
Zenone 1987). Aspects that should be researched to further gain better understandings of
the effects are route difficulty, type of climbing, and current climbing trends (Kunts &
Larson 2005). The route difficulty can give an estimate of the amount of use on each
route (the more difficult, the less used). The various types of climbing involve different
equipment and methods effecting vegetation and geology differently. The climbing
protection mentioned does not directly effect vegetation, however it can effect soil
located on and in the rock, also the physical features of the rock can be altered if
protection is placed improperly. Studies conducted in Danube valley, Germany recorded
damaging effects from climbing such as 1) reduction of plant cover 2) extinction of
disturbance sensitive species 3) clearing of soil from crevices 4) erosion of the cliff and
face 5) increase in ruderal species (Rusterholz, Muller, & Baur2004). This study sampled
92 plots finding a total of 6091 individual plants of 44 different species. Within the
climbed areas species density was 50% lower than unclimbed areas, while species
diversity was 30% lower than in unclimbed areas.
10
Location
Devils Lake
Devils Lake is a popular climbing destination located in close proximity to
Milwaukee, Wisconsin and Chicago, Illinois that receives many climbers from both
areas. Devils lake is located in Wisconsin, 3 miles south of Baraboo, 40 miles North by
northwest of Madison, 80 miles southeast of Lacross, and 100 miles west by northwest of
Milwaukee (Trowbridge 1917). This close proximity to major populations makes this
location a great study site for looking at the impacts of climbing.
Figure 1.
Location of Devils Lake, Wisconsin
11
Devils Lake Wisconsin contains a very unique geological feature having a rare
relief in the central Mississippi Basin. This feature is comprised of two ridges known as
the North Ridge and the South ridge, forming a syncline. These ranges reach elevations
between 1,000 and 1,500 feet above sea level. The Devils Lake formation contains
numerous types of rock including granite, diorite, rhyolite, quartzite, and slate
(Trowbridge 1917). The quartzite came from sand deposited in shallow water above
igneous rock. Over time the gathered sand became very deep reaching depths of 4,000
feet. The sand contained high amounts of quarts, eventually forming sandstone. The rock
has colors ranging from light pink to dark maroon, this is caused by the high amount of
iron that was in the water when the sand was deposited (Schultz 2004) This sand stone
was then metamorphosed to its current state, very dense quartzite through uplift and
syncline folding. The Cambrian and Ordovician times brought large amounts sediment,
depositing it over the hard quartzite hills; this can be seen by residual sandstone and
limestone on the summits of the ridges.
Figure 2. Image displaying the syncline structure of Devils Lake
http://www.nps.gov/history/history/online_books/science/2/chap7.html
12
The formation of Devils Lake was caused by advancing glaciers and moraines
damming off the Devils lake gorge, trapping the water forming the lake (Schultz 2004).
The glaciers also destroyed the vegetation in the area, but once they retreated they left
behind glacial till, outwash sand, and other fine sediments making colonization easy for
pioneer species, starting the first stages of succession (Melder 1987). Devils Lake is
primarily deciduous forest with a tree canopy comprised primarily of white pine,
hemlock, basswood, sugar maple, white oak, shag bark hickory, and yellow birch. The
under story of Devils Lake has white snakes root, goldenrod, horse chestnut, northern bed
straw, new England aster, among others.
Climbing at Devils Lake has become very popular and because of its proximity to
Chicago Illinois and Milwaukee Wisconsin, the distance is just enough to make it a long
day trip. This opens the area up to many commuters and not just locals for numerous
recreational activities such as fishing, boating, hiking, camping, and climbing. However,
while Devils Lake allows climbing, the park is not specifically maintained for climbing.
This means that there are no previously bolted routes; climbers must set anchors around
large boulders or trees. Creating an anchor adds a degree of danger to climbing at Devils
Lake, if anchors are not set properly the results can be life threatening.
Figure 3. Image of properly set anchors on large boulder at Devils Lake
By: Charles Hoover
13
Devils Lake also has general regulations in place to reduce the impact from
recreation and to reduce invasion by non-native plants. Some prevention techniques
include signage and the use of foot brushes to the entrances to the main trails. The
brushes are used to brush invasives off potential carriers. Garlic mustard is the primary
reason for the use of these brushes. Along with each brush station there are informational
areas informing recreationists on the potential dangers of invasive and why it is important
to keep them out. Through awareness the park hopes to educate guests and reduce their
impact. Devils Lake contains many climbing routes that range in various degrees of use
and difficulty. It was hypothesized that routes with the higher climbing activity were
expected to have lower species diversity, and a higher amount of invasive species
compared to unclimbed areas. Furthermore, top routes were expected to contain a greater
level of species diversity in contrast to bottom routes.
Methods
Field Sampling
The effects of rock climbing on vegetation were researched at Devils Lake
Wisconsin. Two bluffs, the east bluff and the west bluff surround Devils Lake. The data
was gathered from the east bluff. Data collection began on 9/17/10 and ended on 9/18/10,
and the temperature of each of these days was 61.2F and 57.6F respectively. Four
routes were randomly selected from the east bluff, using a random number generator. The
routes selected all vary in degrees of use, high use, moderate use, and low use. Two high
use and two low use areas selected for comparison. Degrees of usage were determined
based on the condition of the base of the climb, accessibility to the route, and amount of
climbers present during data collection. The latitude and longitude (waypoint) was
recorded at the top of each location using a GPS unit. The waypoint of each location was
also used to find the corresponding base of the location.
Each waypoint marked the bottom left corner of a 10m x 10m quadrat laid out
using 30m tapes. Species, DBH, and percent cover of the overstory were all recorded
within each quadrat. In addition species diversity was calculated using the Shannon
index of diversity formula (Figure 4):
14
Figure 4. Shannon index of diversity formula
The species were identified using standard field guides (Stan Tekiela 2000). Diameter at
breast height (DBH) was recorded on all trees larger than 10cm in diameter at breast
height. The percent cover of each over story was calculated by judging the percentage of
canopy cover. A random point within the 10m x 10m quadrat was randomly selected
using a random number generator. The bottom left of each quadrat was the starting point
of each random sample (Figure 5). The random number generator was used twice to
obtain an X-axis and a Y-axis for the quadrat; these XY coordinates selected the sight of
sampling within the quadrat. A soil sample was then taken using a soil core. On two
occasions the selected coordinate was over rock a soil sample was unobtainable, and
another point was then selected. In many occasions the soil was rocky or contained a
large amount of organic matter, the core was pushed as far as it could go at each point,
averaging 6 inches.
m
m
Figure 5. Shows the layout of the plots at the top and bottom of each route.
15
Satellite Imagery Methods
Using Idrisi Taiga 2010 true color and false color composite were created. False
color images use infrared to display differences in land use and vegetation. This was done
in Idrisi Taiga with the composite tool, placing thermatic mapper (TM) bands four in the
red image band, TM bands three in the green image band, and TM band two in the blue
image band. The composite tool was also used for creating the true color images using
TM bands one, two, and three in the color bands of blue, green, and red respectively.
Images were taken on 08/31/2009 and 11/03/ 2009 by the USGS using Land Sat 4&5
TM. Two different months were selected to show the differences in vegetation. August
when vegetation is in full growth (Figure 6) and early November when the canopy and
native species have dropped their leaves (Figure 7). Viewing the different TM bands will
allow areas containing both non-native and other species that hold their leaves beyond the
summer months to be identified.
16
Figure 6. True color image taken 2009
Figure 7. True color image taken November 2009
17
Lab Methods
Using the La Motte Soil Texture unit the soil texture of each of the soil samples
was found. Each sample was sieved with 1.7mm mesh wire to separate out the gravel and
large organic material. The weight of the gravel and soil was taken using an electric
balance to the nearest milligram. Fifteen ml of each sample was placed in a test tube, with
29 ml of water and 1 ml of dispersant. The test tube was then gently shaken for
approximately two minutes and then allowed to let stand for exactly 30 seconds. The
solution was then poured into a new test tube, without displacing the solid material at the
bottom of test tube one. The solution in the second test tube was then allowed to stand for
30 minutes. The solution was then poured into another clean test tube, being careful not
to displace the solid material in the bottom of the second test tube. By adding the amount
in the first test tube and the second test tube, and subtracting from 15 ml, the amount of
test tube three can be found. The amount in each test tube allows for percentage of sand,
silt and clay to be calculated with the following calculations:
Percent Sand = Reading in ml of test tube one x 100
Total Volume
Percentage Silt = Reading in ml of test tube two x 100
Total Volume
Percentage Clay = Calculated Volume x 100
Total Volume
Using the USDA soil texture field chart the soil texture triangle was then used to find the
soil texture of each sample, based on the percentages of sand, silt, and clay.
Statistical methods
A paired T-test was used to analyze the variation between heavily used climbing
routes and low use climbing routes on both top and bottom of the routes.
18
Results
Field Results
The level of disturbance at climbing routes in Devils Lake was observed to impact
plant percent cover such that low disturbance areas at the top and bottom of the routes
contained the highest percent cover, whereas the high disturbance areas exhibited the
lowest (Figure 8).
Mean Percentage Cover
Mean Percentage Cover Vs.
Disturbance
140
120
100
80
60
40
20
0
High
Low
High
Top
Low
Bottom
Disturbance
Figure 8. Mean percentage cover of overstory for each top and bottom plots
In total there were seven different species recorded for the over story, all ranging
in abundance. In both the bottom plots and top plots white oak appeared the most
frequently (Table 1). Each species mean DBH was calculated for both the top and bottom
plots, American basswood had the greatest DBH of both the top and bottom plots, and
shagbark hickory had the lowest DBH measured in the top plots. Within the bottom plots
white oak had the largest DBH and the one buckthorn had the lowest DBH (Table 1).
19
Table 1. Mean DBH (+/- standard deviation) of each species and the number of
individuals in the overstory of bottom and top plots of all four routes
TOP
Bottom
Species
American
Basswood
Tilla americana
Red Cedar
Thuja occidentalis
White Pine
Pinus strobus
White Oak
Quercus alba
Shagbark Hickory
Carya ovata
White Oak
Quercus alba
Shagbark Hickory
Carya ovata
White Pine
Pinus strobus
White Cedar
Thuja occidentalis
Buckthorn
Rhamnus
Mean DBH
SD +/-
Number of
Individuals
55.1
28
26.5
26.2
16.8
36.1
34.2
33.6
11
10
6.2
1
0
3
6.8
1
0
12
6.9
8
13.6
11
0
1
16.1
5
0
1
0
1
In the understory, goldenrod had the greatest number of individuals in the top plots and
false salmons seal had the least amount of individuals (Table 2). In the bottom plots
white-flowered leaf-cup had the most individuals, while nightshade had the least. (Table
2.)
20
Table 2. The number of each recorded understory species for both the top and
bottom of all four routes.
Under story Species
Number of
Individuals
Goldenrod
TOP
Bottom
Solidago canadensis
Woodland Sunfower
Helianthus Diravicatus
Horse Chestnut
Aesculusglabra
White Snakeroot
Ageratina altissima
Buckthorn
Rhamnus cathartica
White Oak Sapling
Quercus alba
Northern Bed Straw
Galium boreale
New England Aster
Aster novae-angliae
Shagbark Sappling
Carya orata
Flase Solomons Seal
Smilacina racemosa
White-Flowered-LeafCup
Polymnia canadensis
White Snakeroot
Ageratina altissima
Horse Chestnut
Aesculusglabra
Goldenrod
Solidago canadensis
Devils Beggar-ticks
Bidens frondosa
Night Shade
Solanum dulcamar
284
115
79
75
30
29
16
13
4
2
36
24
17
12
5
1
21
A soil pH of 4 was recorded for all plots both top and bottom. The soil collected from the
top plots consisted of two soil types sandy clay loam and silt loam. Soil collected from
the bottom blots was found to also be silt loam and sandy clay loam. The organic material
found in the bottom plots was associated with the amount of leaf litter over partially
exposed bedrock (Table 3).
Table 3. Soil pH and texture of all four routes
Top Plots
wp 132
wp 134
wp 135
pH
4
4
4
wp 136
Bottom
Plots
wp 132
4
wp 134
wp 135
4
4
wp 136
4
4
Texture
Silt loam
Silt loam
Silt loam
Sandy clay
loam
Organic
Sandy clay
loam
Organic
Sandy clay
loam
The low disturbance areas had a mean species diversity of 29.5 (+/- 27.9) and the high
disturbance areas had a mean diversity of 10.8 (+/- 8.3 SD). Species diversity differed
between the top and bottom areas of the routes. The low disturbance areas at the top and
bottom of the routes contained the higher species diversity; however, the low disturbance
areas at the top of the routes exhibited the highest species diversity overall (Figure 9.). At
both the top and bottom routes high disturbance areas were observed to contain lower
species diversity (Figure 9.)
22
Mean species Diversity for High Vs. Low
Disturbance of Top and Bottom Routes
Mean Species Diversity
80
70
60
50
40
30
20
10
0
High Disturbance Low Disturbance High Disturbance Low Disturbance
Top
Bottom
Figure 9. Mean species diversity of both the high and low disturbance climbing routes at
the top and bottom
Satellite Imagery Results
A change in foliage was observed from August to November 2009 (Figures 10,11). Plants
primary growing season is in the summer months, when foliage is required for
photosynthesis (Figure 10). From the end of summer to fall native species shed their
leaves. As exhibited, other plants including non-native species hold onto their leave for a
longer period of time (Figure 11).
23
Figure 10. False color image taken August 2009
Figure 11. False color image taken November 2009
24
Discussion
Field and lab data collected from plots at Devils Lake, Wisconsin demonstrate
significant differences between the top and bottom of the low use climbing routes and
high use climbing routes. The high disturbance areas exhibited lower species diversity
and percent cover due to accessibility while the low disturbance areas at the top and
bottom of routes contained the highest species diversity and percent cover. Percentage
cover was taken at each site; the top plot of low disturbance contained the greatest mean
species diversity. The low disturbance bottom plot also contained greater mean species
diversity than the highly disturbed area.
There is relationship between the use of the routes and the percentage cover.
There may be a greater percent cover at the low use routes because there is less
disturbance and the areas are much harder to access, allowing for natural growth. The low
use routes were fairly difficult to access and were far from the main trails; this may
influence the high percentage cover found under low anthropogenic disturbance (Figure
8). The data did not support the hypothesis that the high use areas would contain more
invasive species. Very few invasive species were found at any of the study sites, however
buckthorn was present at two of the study sites. This low amount of non-native species
may be due to the park conservation, large warning are posed at major trail entrances
requiring guests to brush their feet, removing any unwanted species. Many native species
were recorded that would be expected to find in mixed conifer-deciduous forest
(Table1&2).
The base plots soil samples consisted of primarily sandy clay loam, this may be
due to the location at the base of the cliffs. Devils Lake was once sand containing high
amounts of quarts that eventually formed sandstone, which metamorphosed to its current
state. Being previously sand and sand stone explains the sandy soils at the base of the
cliffs. At the top of the cliffs however the majority of the soil textures at each plot were
silt loam. The soil was also a darker color than the soil at the base of the cliffs. This is
from the soil being primarily decayed plant material, with little to no sand or gravel. The
top and bottom plots each had different soil types but all of the plots had a pH of four.
This is believed to be from the large amount of decomposing pine needles in the area,
25
which are the dominant canopy species in the area. Over time pine needles can lower the
pH of the soil, making it more suitable for conifer trees, which thrive in low pH soil
(Table 3.).
Mean species diversity was calculated using the Shannon index for the high use
and low use climbing routes. With one degree of freedom the t-values of 1.49 for the high
and low disturbance top plots and 1.90 for the high and low disturbance bottom plots was
calculated using a paired t-test rejecting the null hypothesis. The mean species diversity
was much higher with the low use climbing routes (29.5) compared to the high use routes
(10.8). The difference found in the species diversity between the high use routes and the
low use routes supports the hypothesis that there would be lower species diversity at the
heavily climbed routes. However the statistical analysis rejected the null hypothesis with
one degree of freedom, this may be due to the very small sample size. The location,
accessibility, and development of the heavily climbed routes may also have influenced
the species diversity. The heavily climbed routes have bases that are accessible by paved
trails making them more convenient, thus more popular. The convenience of the easily
accessible routes brings greater anthropogenic disturbances from climbers. Species
diversity may have also have been reduced due to paved paths in proximity to the high
use routes (Figure 9).
The low disturbance climbing routes reported higher species diversities for both
the base and top of each route. Low species diversity was recorded for each of the high
disturbance routes (Figure 9). The plots containing high species diversity also reported
greater percent cover for both top and base plots (Figure 8.). The greater species diversity
may be due to the lack of disturbance. The routes with the highest percentage cover and
species diversity were low disturbance route. While the areas with the lowest percentage
cover and species diversity were high disturbance routes.
The false color image of Devils Lake taken in November demonstrates partial
understory represented as light red surrounding the cliff area (Figure 11). As observed,
the majority of native species have shed their leaves by November, whereas non-native
species such as buckthorn hold their leaves much longer. The red color could also
indicate coniferous trees present in the area that hold their leaves year round. The false
26
color image taken of Devils Lake demonstrates surrounding canopy represented in red
(Figure 10.) As observed, the canopy of the study sites in August is in full foliage.
This study shows possible correlations between rock climbing and vegetation.
The hypothesis was partially supported by the data collected at each plot on species
diversity showing lower species diversity at high disturbance routes; however, invasive
species were not present at the majority of the routes. If this study were to be replicated
more sample areas would be needed for a better representation both high use and low use
routes. Also adding additional parks that allow climbing would create a better
representative sample. In addition further research could be conducted in different
ecosystem types to determine environmental responses.
The incredible expansion and resulting increases in participation in rock climbing
raises many questions for land managers and park officials. What role should they play in
this recreational activity? To what degree should forms of the sport be regulated? Which
participants should receive special management interventions? These questions are being
asked everywhere rock climbing is present. Many public and private landowners have
developed rules and regulations specifically for climbers. Many of these places simply
use methods of information to try and reduce impact. A study done by Borrie and
Harding in the Bitterroot Valley, Montana looked at effective recreation visitor’s
communication strategies of rock climbers. This study found that those people who
understand their impact do not use “leave no trace” practices. Rock climbing is a very
aesthetically pleasing sport, so the condition of the rock is important, being a nonrenewable resource. “More than any other sport, rock climbing needs an ethical code
with respect to the environment. Unlike most other forms of recreation, the very essence
of the rock climbing depends on the natural scene, a nonrenewable resource. The
popularity of rock climbing is causing a tremendous human impact of the cliffs and the
surrounding land at Devil’s Lake.” (Climbers Guide to Devils Lake 14-15)
The low impact from invasive species may be due to the proper conservation efforts
being practiced by park management. If other parks were to adopt the same management
practices as Devils Lake, the impact from non-native species may be reduced. With
further implementation of rules and regulations the impact from rock climbing may be
reduced.
27
Work Cited
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Strategies: Rock Climbers in the Bitterroot Valley, Montana (USDA Forest
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Cole, D. N. (1996). Wilderness Recreation in the United States: Trends in Use, Users,
and Impacts. International Journal of Wilderness, 2(3): 14-18.
Custer, D. (2007). The Evolution of Climbing Equipment Standards [PDF document].
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Conservation Biology, 20(3): 821-832.
Lockwood, Julie L., Martha F. Hoopes, and Michael P. Marchetti. Invasion Ecology.
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28
Taylor, A. R. & Knight R. L. (2003). Wildlife Responses to Recreation and Associated
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