Michigan Horsemen P.L.U
THE RIGHT TO RIDE
ELK RUB
Elk population being surveyed from the air
Count is first in five years
HILLMAN - Wildlife biologists took to the skies over northern Lower Michigan to chase down the state's elk herd.The first scientific survey of Michigan's elk population in five years began Monday with two state Department of Natural Resources airplanes swooping low over the Pigeon River Country State Forest. State wildlife officials peered out the windows of Cessna 182s as they flew from Hillman Airport to search for elk from about 500 feet up.
"If we see animals, we circle around and count them, and also try to determine how many bulls, cows and calves there are," said Brian Mastenbrook, DNR wildlife biologist.
The project is coordinated by Michigan State University doctoral student Dan Walsh. The 28-year-old researcher broke down the state's elk range into two-by-six-mile sections that will be surveyed at random.
"Working with a big game animal like elk is really interesting. It's a neat critter," Walsh said.
Native elk disappeared from Michigan around 1875 and today's herd dates to 1918, when seven western animals were released near Wolverine. The elk herd grew to about 1,500 animals in the early 1960s, but diminished habitat quality and poaching left only 200 animals by 1975.
The elk herd recovered over the decades to recent estimates of between 800 and 900 animals. Hunting resumed in 1984 and now a lottery determines which Michigan hunters get permits. Last year only 155 hunters got a chance from among more than 41,000 applicants.
Walsh said the population survey will document elk behavior, as well as how many are grouped together and what type of ground cover they are found in.
Mastenbrook said officials will also learn how the elk range is changing.
"We know we've got some big clumps of animals outside the management area," he said.
That territory includes all of the Pigeon River Country State Forest, west to Interstate 75 and east to about five miles beyond M-33. The elk that roam east of that highway are a growing concern for the DNR.
"We're worried about elk getting TB from the deer. We've found four elk with TB to date, but none in the last two years," Mastenbrook said. "We have some infected animals, but we don't think the whole herd is infected."
EFFECTS OF OFF-ROAD RECREATION ON MULE DEER AND ELK
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Movement Rates of Elk
Movement rates of elk were substantially higher during periods of all four off-road activities as compared to periods of no human activity (Figure 2). Responses of elk to the morning and afternoon runs were clearly evident, with the most pronounced increase in movement rates observed during the hours when each off-road activity occurred (Figure 2). For example, our morning pass on transects began between 0830 and 0930 Pacific Daylight Time (PDT), and highest movement rates for elk occurred in the hours immediately after, from 0900-1100, during all four activities (Figure 2). Moreover, lunch break for participants in the experiment occurred at or near noon, and movement rates for elk dipped to their lowest level at noon during all activities. Finally, we resumed each activity at 1230-1300 PDT, and movement rates for elk substantially increased immediately after (Figure 2).
Movement rates were substantially higher for elk during the morning pass compared to the afternoon pass for all four activities (Figure 2). Movement rates of elk during the afternoon pass, however, stayed well above the rates observed during the periods of no human activity (control period, Figure 2). Movement rates during the afternoon pass declined after 1500 PDT, when afternoon activities ended.
For the morning pass, movement rates of elk were highest during ATV riding, second-highest during mountain bike riding, and lowest during hiking and horseback riding (Figure 2). Movement rates of elk also stayed higher, over a longer period, during the afternoon ATV run, compared to lower rates during afternoon horseback riding, mountain bike riding, and hiking. Peak movement rates of elk during the morning pass were highest for ATV riding (21 yards/minute [19 m/min]), followed by mountain bike riding (17 yards/minute [16 m/min]) and horseback riding and hiking (both about 15 yards/minute [14 m/min]). For the afternoon run, movement rates of elk again were highest during ATV riding (13 yards/minute [12 m/min]), followed by horseback riding (about 11 yards/minute [10 m/min]) and hiking and mountain bike riding (about 10 yards/minute [9 m/min]).
By contrast, peak movement rates of elk during the control periods did not exceed 9 yards/minute (8 m/min). Moreover, peak movement rates during the control periods stayed below 8 yards/minute (7 m/min) during daylight hours of 0800-1500, the comparable period of each day when off-road treatments were implemented.
Interestingly, movement rates of elk also were higher than control periods at times encompassing sunrise and sunset for the days in which an off-road activity occurred, even though humans were not present at these times of day (Figure 2). These higher movement rates near sunrise and sunset suggest that elk were displaced from preferred security and foraging areas as a result of flight behavior during the daytime off-road activities. In particular, movement rates of elk at or near sunrise and sunset were higher during the 5-day treatments of mountain bike and ATV activity (Figure 2). This finding will be studied in detail in future analyses.
Flight Responses of Elk
The estimated probability of elk flight from a human disturbance was highly dependent on distance. When elk and humans were close to one another, the maximum probability of a flight response was approximately 0.65 during ATV, mountain bike, and hiking activity, and about 0.55 during horseback riding (Figure 3). Higher probabilities of flight response occurred during ATV and mountain bike activity, in contrast to lower probabilities observed during hiking and horseback riding (Table 1). Probability of a flight response declined most rapidly during hiking, with little effect when hikers were beyond 550 yards (500 m) from an elk. By contrast, higher probabilities of elk flight continued beyond 820 yards (750 m) from horseback riders, and 1,640 yards (1,500 m) from mountain bike and ATV riders (Figure 3).
Conclusions and Interpretations
Elk
Movement rates and probabilities of flight response for elk were substantially higher during all four off-road activities compared to control periods of no human activity. Consequently, off-road recreational activities like those evaluated in our study appear to have a substantial effect on elk behavior. The energetic costs associated with these treatments deserve further analysis to assess potential effects on elk survival. For example, if the additional energy required to flee from an off-road activity reduces the percent body fat of elk below 9 percent as animals enter the winter period, the probability of surviving the winter is extremely low (Cook et al. 2004). Animal energy budgets also may be adversely affected by the loss of foraging opportunities while responding to off-road activities, both from increased movements, and from displacement from foraging habitat. These potential effects will be evaluated as part of future analysis.
Our results from 2002 also show clear differences in elk responses to the four off-road activities. Elk reactions were more pronounced during ATV and mountain bike riding, and less so during horseback riding and hiking. Both movement rates and probabilities of flight responses were higher for ATV and mountain bike riding than for horseback riding and hiking.