On Thu, 22 Apr 2004 15:08:29 GMT, " S o r n i" <
[email protected]> wrote:
..Mike Vandeman wrote:
..>> From: "Don Weir" <
[email protected]>
..
..> However there
..> is little evidence scientifically and in engineering
..> that a bicycle will cause more erosion than a hiker,
..> cause more impact on wildlife, et cetera.
..
..EXACTLY!!!
That's what all mountain bikers (but no one else) thinks. However:
FINALLY, a careful, honest study showing that mountain biking is more harmful to
wildlife than hiking and horseback riding!
Mike
Subject: ORV wildlife impacts
Date: Thu, 22 Apr 2004 15:41:10 -0700
EFFECTS OF OFF-ROAD RECREATION ON MULE DEER AND ELK
Michael J. Wisdom Research Wildlife Biologist
USDA Forest Service, Pacific Northwest Research Station
Forestry and Range Sciences Laboratory
1401 Gekeler Lane, La Grande, Oregon 97850
Phone (541-962-6532), fax (541-962-6504), Email
[email protected]
Alan A. Ager
Operations Research Analyst
USDA Forest Service Umatilla National Forest
2517 Hailey Ave., Pendleton, OR 97801
Phone (541-278-3740) fax (541-278-3730)
Email
[email protected]
Haiganoush K. Preisler
Statistician
USDA Forest Service, Pacific Southwest Research Station
800 Buchanan St., Albany, CA 94710
Phone (510-559-6484), fax (510-559-6440)
Email
[email protected]
Norman J. Cimon
Systems Analyst
USDA Forest Service, Pacific Northwest Research Station
Forestry and Range Sciences Laboratory
1401 Gekeler Lane, La Grande, Oregon 97850
Phone (541-962-6551), fax (541-962-6504)
Email
[email protected]
Bruce K. Johnson
Starkey Project Leader
Oregon Department of Fish and Wildlife
Forestry and Range Sciences Laboratory
1401 Gekeler Lane, La Grande, Oregon 97850
Phone (541-962-6556), fax (541-962-6504) Email
[email protected]
Suggested Citation:
Wisdom, M. J., H. K. Preisler, N. J. Cimon, B. K. Johnson. 2004. Effects
of Off-Road Recreation on Mule Deer and Elk. Transactions of the North
American Wildlife and Natural Resource Conference 69: in press. Wisdom
et al. 2
Effects of Off-Road Recreation on Mule Deer and Elk
Michael J. Wisdom
U.S. Department of Agriculture, Forest Service, Pacific Northwest
Research Station
La Grande, Oregon
Alan A. Ager
U.S. Department of Agriculture, Forest Service, Umatilla National Forest
Pendleton, Oregon
Haiganoush K. Preisler
U.S. Department of Agriculture, Forest Service, Pacific Southwest
Research Station
Berkeley, California
Norman J. Cimon
U.S. Department of Agriculture, Forest Service, Pacific Northwest
Research Station
La Grande, Oregon
Bruce K. Johnson
Oregon Department of Fish and Wildlife
La Grande
Introduction
Off-road recreation is increasing rapidly in the United States,
especially on public lands (Havlick 2002, U.S. Department of Agriculture
Forest Service 2004). An expansive network of roads provides easy access
to many public lands, which facilitates off-road uses in the form of
all-terrain vehicles (ATVs), horses, mountain bikes, and foot traffic.
No research, however, has evaluated effects of these off-road activities
on vertebrate species in a comparative and experimental manner (see
review by Gaines et al. 2003). One recent study (Taylor and Knight
2003a) evaluated bison (Bison bison), pronghorn (Antilocapra americana),
and mule deer (Odocoileus hemionus) responses to mountain biking and
hiking. This study, however, did not include ATV or horseback riding,
nor did it include experimental controls needed to assess cause-effect
relations.
To address these knowledge gaps, we initiated a manipulative, landscape
experiment in 2002 to measure effects of off-road recreation on mule
deer and elk (Cervus elaphus), two charismatic species of keen
recreational, social, and economic interest across western North
America. Our objectives were to (1) document cause-effect relations of
ATV, horseback, mountain bike, and hiking activities on deer and elk,
using these off-road activities as experimental treatments and periods
of no human activity as experimental controls; (2) measure effects with
response variables that index changes in animal or population
performance, such as movement rates, flight responses, resource
selection, spatial distributions, and use of foraging versus security
areas; (3) use these response variables to estimate the energetic and
nutritional costs associated with each activity and the resultant
effects on deer and elk survival; and (4) interpret results for
recreation management.
Our research began in 2002 and ends in 2004. In this paper, we present
findings from 2002 to address parts of objectives 1, 2, and 4. We
specifically focus on changes in movement rates and flight responses of
mule deer and elk in relation to the off-road activities, as compared to
periods of no human activity. We then describe potential uses of the
results for recreation management.
We present findings from our first year of study because of the urgent
need for timely management information to address the rapid growth in
off-road recreation (U.S. Department of Agriculture Forest Service
2004). For example, ATV use on public lands has increased seven-fold
during Wisdom et al. 3
the past 20 years, and many conservation groups are calling for
widespread restrictions on ATV travel (U.S. Department of Agriculture
Forest Service 2004). Yet no studies have evaluated the role of ATVs
compared to other off-road activities, such as mountain biking and
horseback riding, which also are increasing rapidly. Without
comprehensive studies of ATV effects in relation to other recreation,
the debate over ATV is likely to intensify. Our study was designed to
measure a variety of ungulate responses to address this debate, such
that results can be used to identify compatible mixes of different
off-road recreational opportunities in relation to deer and elk
management.
Throughout our paper, we refer to off-road recreation, both motorized
and non-motorized, as that occurring on trails, primitive (unpaved)
roads, or areas without trails or roads. This definition complements the
term "off-highway vehicle (OHV) use," which refers to motorized vehicle
use on any surface beyond highways (U.S. Department of Agriculture
Forest Service 2004), but which does not include other forms of
non-winter recreation that typically occur on primitive roads and
trails, such as hiking, horseback riding, and mountain biking.
Study Area and Technologies
We conducted our research at the Starkey Experimental Forest and Range
(Starkey, Figure 1) in northeast Oregon, a facility equipped to evaluate
real-time and landscape-level responses of deer and elk to human
activities under controlled experimentation (Rowland et al. 1997, Wisdom
et al. 2004a). The facility encompasses spring, summer, and fall ranges
typical of those used by mule deer and elk in the western United States.
Timber harvest, livestock grazing, motorized traffic, hunting, camping
and other public uses of Starkey also are managed like those on National
Forests in the western United States, thus providing a large inference
space for research findings (Rowland et al. 1997, Wisdom et al. 2004a).
An essential research component at Starkey is the ungulate-proof
enclosure, one of the largest in the world, which allows scientists to
evaluate ungulate responses to human activities over large areas and
under controlled conditions (Bryant et al. 1993, Rowland et al. 1997).
Another key technology is the automated tracking system (ATS), which can
generate up to one animal location every 20 seconds, 24 hours a day,
from April through December each year (Rowland et al. 1997, Kie et al.
2004). Additional technologies include maps and databases of more than
100 environmental variables to relate animal movements to the landscape
experiments, and supporting methods and software to analyze these data
(Rowland et al. 1997, 1998).
Implementing the Recreation Treatments
To meet our objectives, a network of off-road transects was established
and run in 2002, using ATV, horseback, mountain bike, and hiking
activities as experimental treatments in the 3,590-acre (1,453-ha)
northeast study area (Figure 1). Approximately 20 miles (32 km) of
transects were established (Figure 1), over which ATV, horseback,
mountain bike, and foot traffic was experimentally applied from
mid-April through October. Locations of each transect were established
with Global Positioning System (GPS) units (Figure 1). Transects were
located on flat or moderate terrain typically used by off-road
activities. Primitive roadbeds, like those often established by off-road
vehicles (U.S. Department of Agriculture Forest Service 2004), were
included in the transects. Use of roadbeds and trails to implement human
activities is referred to as a "tangential" experimental approach
because animals are not targeted directly by the activities (Taylor and
Knight 2003b). This is in contrast to a direct experimental approach,
such as testing the reaction of nesting birds to designed encounters
with humans at nest sites.
A sufficient number and length of transects were established to
encompass all portions of the northeast study area (Figure 1). Each
off-road activity was run on a given transect twice daily, once in the
morning and once in the afternoon, during a 5-day period; this daily
frequency of activity corresponds to traffic frequency on Starkey roads
that produced an avoidance response by elk in earlier research (Wisdom
1998, Wisdom et al. 2004b). Wisdom et al. 4
A particular activity for a given morning or afternoon was completed by
one to three people who rode ATVs ("four-wheelers" or "quads"), mountain
bikes, or horses, or hiked as a group. On most days, group size
consisted of two people moving as a pair; that is, by two people hiking
or each riding ATVs, mountain bikes, or horses. A group size of two,
with a range of one to three people, often is typical for these
recreation activities in non-wilderness portions of National Forests
(personal communication, D. Barrett, Wallowa-Whitman National Forest).
Group size can vary substantially, however, with larger groups of 5-10
ATV riders or horseback riders, for instance. We had neither the
resources nor the experimental options to include these larger groups as
treatments in our study. Moreover, group size of mountain bikers and
hikers often does not approach 5-10 people, and we wanted to maintain
approximately the same group size across all four activities. A group
size of two people, with a range of one to three people, provided this
consistency.
For ATV travel, a pair of riders could easily cover the 20 miles (32 km)
of transects during a given morning or afternoon. A pair of mountain
bike riders, however, could cover about 50 percent of the 20 miles (32
km) in a morning or afternoon. Horseback riders and hikers could cover
about 30 percent. Because we wanted to standardize the experiment by the
same number of transect runs or "passes" (twice daily) among all four
off-road activities, two different groups of mountain bikers, and three
groups of horseback riders or hikers, were used to obtain complete
coverage of transects for a given morning or afternoon. For mountain
biking, the transects were divided in half, with each of the two groups
assigned to ride a different half of the 20 miles (32 km) in a morning
or afternoon. Similarly, three groups of horseback riders or hikers,
each assigned to hike a different third of the transect length, were
used for each morning and afternoon to obtain complete coverage of
transects.
Each of the four off-road activities was implemented under an
"interrupted" movement design, where humans were allowed to momentarily
stop to view animals for less than 1 minute when animals were observed.
This is in contrast to a "continuous" movement design, where human
activities are not delayed or stopped when animals are observed (Taylor
and Knight 2003b).
Each 5-day period of off-road activity was followed by a 9-day control
period, during which no human activities occurred in the study area.
This pattern was followed from mid-April through October, resulting in
three replicates of each of the four off-road activities. Each 5-day
replicate of an off-road activity thus was paired with a 9-day control
period that immediately followed the replicate. Only one type of
off-road activity (ATV, horseback, mountain bike, or hiking) occurred on
transects during a given 5-day replicate. The chronological order of
each off-road activity, in terms of which activity occurred during the
first 5-day replicate in late April, versus the next 5-day replicate in
early May, and so on, was randomly chosen.
Throughout the experiment, all human entry beyond the four off-road
activities, including administrative use of roads, was prohibited to
eliminate the confounding effects of other human activities with animal
response to the off-road activities. Consequently, human activities such
as timber harvest, road traffic, camping, and hunting did not occur
during the study because of their confounding effects.
Measuring Animal Responses
To monitor animal responses, 12 female mule deer and 12 female elk were
radio-collared among a larger population of approximately 25 female deer
and 100 female elk present in the northeast study area in early April.
Movements of these radio-collared animals were monitored with the ATS
(Rowland et al. 1997). During periods of off-road activity, locations of
each radio-collard deer or elk were generated at approximately 10-minute
intervals. Locations of humans engaged in each off-road activity were
generated at approximately 1-minute intervals, using GPS units carried
by one of the persons in each group of hikers or riders of ATVs, horses,
or mountain bikes. Use of the automated telemetry system to track animal
movements, combined with the use of GPS units to track human movements,
provided real-time, unbiased estimates of the distances between each
ungulate and group of humans.
Our method of estimating distances between ungulates and humans
contrasts strongly with the use of direct observation, using
rangefinders or other devices, to measure distances. Direct observation
as Wisdom et al. 5
a means of estimating distances between ungulates and humans is likely
to be biased by the proportion of deer or elk whose reactions to human
activities cannot be observed because such reactions are different than
those of animals that can be observed. For example, some animals may run
from human activity at distances beyond the view of observers, while
other animals may react at close distances to, and in view of,
observers. This bias in observed distances would result in
underestimation of the true distance at which animals react to the human
activity. In other cases, animals may flee from humans at close
distances, but not be viewed because such animals seek dense cover
during flight; this bias would result in overestimation of distances. We
avoided such biases with the use of our automated telemetry system and
GPS units to continuously monitor the movements of ungulates and humans
throughout our study.
We also located radio-collared animals during the 9-day periods of no
human activity, or control period. Approximately two locations of each
radio-collared animal were obtained every hour during control periods,
to establish baseline information about areas of deer and elk use,
habitat selection, movement rates, and flight responses in the absence
of human activities. For this paper, we analyzed two types of animal
reactions: (1) movement rate and (2) probability of flight response. We
evaluated movement rate and probability of flight response because both
