Short term behavioural and physiological response of moose Alces alces to military disturbance in Norway

0006-3207(96)00004-3

ELSEVIER

Biological Conservation 77 (1996) 169 176 Copyright © 1996 Elsevier Science Limited Printed in Great Britain. All rights reserved 0006-3207/96/$15.00+0.00

SHORT TERM BEHAVIOURAL A N D PHYSIOLOGICAL RESPONSE OF MOOSE Alces alces TO MILITARY DISTURBANCE IN NORWAY Reidar Andersen, John D. C. Linnell & Rolf Langvatn Mammalian Ecology Research Group, Norwegian Institute for Nature Research, Tungasletta-2, 7005 Trondheim, Norway (Received 10 January 1995; accepted l0 October 1995)

Abstract The response of moose Alces alces to mifitary disturbance in a multi-use landscape was studied Four individual free-ranging moose, fitted With heart-rate transmitters, were subjected to specific stimuli in controlled disturbance trials, and 12 radio-collared moose were followed for 3-week-long periods, before, during, and after large-scale military manoeuvres. In the disturbance trials the moose showed much shorter flush distances (the distance from the disturber at which flight began) and normal heart rate returned sooner after being disturbed by mechanical stimuli than after human stimuli. There was no significant difference in flight distance or maximum heart rate for these two categories of disturbance. There was a significant, inverse relationship between flushing distance and both flight distance and the time required for heart rate to return to normal. During manoeuvres the home range size increased, but only one moose within the disturbed area made a significant home range shift. We hypothesised that the greater fear of humans than of vehicles is due to the strict ban on hunting from vehicles, and to the familiarity with unthreatening, all-terrain, timber-cutting vehicles. We concluded that military activity of the type studied here is not especially detrimental to moose, and that the effects of their activity should not differ from comparable civilian harassment. Copyright © 1996 Elsevier Science Ltd Keywords: moose, military activity.

Alces,

disturbance,

reserves, and even within them they are rarely totally undisturbed (Cederna & Lovari, 1985; Stockwell & Bateman, 1991). Knowledge on how ungulates respond to different types of disturbance is therefore important for the effective management of wildlife in these multiuse landscapes (Hansen et al., 1993). Individuals can respond to disturbance in two ways: first, they can move out of their normal home range in search of an undisturbed area (Kuck et al., 1985), or secondly, they can react to the disturbance within their normal home range (Root et al., 1988). The first type of response is measurable by monitoring their home ranges before, during and after a disturbance, and would be expected to carry a cost to the individual by forcing it to occupy unfamilar terrain. The second type of response is less obvious and can vary from physiological effects such as a slight increase in heart rate, through subtle changes in activity pattern to flight. Measurement of responses requires close observation of individuals or the remote monitoring of heart rate during a disturbance. Intermediate responses are also common, where home ranges are temporally abandoned, and are then returned to later (Jeppesen, 1987). Among the range of disturbances with which ungulates are confronted, including logging, hunting and recreation, military activities are regarded as among the most controversial from a human point of view. The large numbers of people, and especially of equipment (tanks, fighter jets, helicopters, artillery) involved in manoeuvres are often judged from an anthropocentric perspective to be extreme disturbances. However, several studies have shown that people and dogs elicit greater flight responses than machines (e.g. skiers versus snowmobiles, Freddy et al., 1986), and many military training areas contain abundant wildlife (Kvam & Stensli, 1991). In fact, the number of publications dealing with military activity are few, and the idea that military disturbance has more impact than other forms of recreational or exploitative activity has little scientific support. Moose are very abundant in the forests of Scandinavia, where they have taken advantage of the modern clearcut/replant system of forestry to increase greatly in

harassment,

INTRODUCTION As areas of true, undisturbed wilderness rapidly decrease, wild ungulates are forced to integrate more and more into a human-influenced environment, which presents novel and often rapidly changing habitats (Wiens, 1990; Andersen, 1991) and many sources of recreational and exploitative disturbance. Most ungulate populations remain outside national parks and Correspondence to: Reidar Andersen, Tel. + 47 73 58 05 00; Fax + 47 73 91 54 33; e-mail reidar'andersen@nina'nina'n° 169

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R. Andersen, J. D. C. L&nell, R. Langvatn

numbers. They represent a considerable economic resource, providing 5600 tonnes of meat annually in Norway, often exceeding the value of timber harvested from the same land. Controversy surrounds the adverse effects of military activity on moose in forested areas. Land owners are concerned that military manoeuvres on their land will either frighten all moose away from the area, or will cause stress detrimental to the moose, both having the effect of reducing the number of harvestable moose from their land. Here we present the results of: (1) a series of experiments on moose which were fitted with heart-rate transmitters and which were exposed to a variety of military-related stimuli; and (2) a study of the effect of a full-scale military exercise on the spatial distribution of radio-collared moose. On the basis of existing knowledge on the responses of wild ungulates to disturbance, we hypothesised that moose would show greater fear responses to stimuli that could be identified as human, as opposed to mechanical, and that they would respond to extensive disturbance by seeking shelter within their normal home range and not make large range shifts. STUDY AREAS The studies were carried out in three different areas, two in Hedmark County in east central Norway. The climate here is continental with relatively warm, dry summers and cold winters. The habitat is almost entirely forested with dry pine Pinus sylvestris forest in the lower parts of river valleys, and more productive forests higher up, where pine was mixed with spruce Picea abies and birch Betula pubescens. Area 1 (Terningmoem 60.8°N, l l°E) is a 30 km 2 military shooting and manoeuvering area and provides both winter and summer feeding grounds for a population of both resident and migratory moose. Area 2 (Amot, 61°N, l l°E) is 1500 km 2, mostly privately owned and used for commercial forestry and hunting. The main features were three broad river valleys (Rena, Julussa and Osa) which flow into an artifical lake (Lopsjoen). The valley bottoms hold most moose in the winter time as many migrate upwards in summer to distinct ranges. Area 3 (Songli, 63.2°N, 9.5°E) is a 80 km 2 state property in South Trondelag County in central Norway. Here the vegetation consists of spruce forest, interspersed with bogs. The climate is somewhat similar to the other areas, although milder due to a stronger oceanic influence.

MATERIALS AND METHODS Capture and instrumentation A total of 16 adult (>1.5 years old) moose were captured by chemical immobilisation with M-99 from helicopters following standard procedures (Langvatn & Andersen, 1991). Heart-rate transmitters were implanted in the chest and throat regions as described in Langvatn and Andersen (1991). A total of 12 moose, includ-

ing one bull with a heart-rate transmitter, were within the area used for the manoeuvres i n / k m o t (Area 2). Of these, eight cows were radio-collared in winter of the previous year (1993) and the others in late summer 1994. In each of the other two areas two moose (two bulls at Songli, two cows at Terningmoen) with heartrate transmitters were available for disturbance trials.

Data collection and disturbances In Amot, moose were radio-tracked in three distinct periods: for six days prior to the military manoeuvres, followed by a day's break, then seven days during the manoeuvres, followed by another day's break, and for six days after the manoeuvres. These periods are hereafter generally referred to as before (B), during (D) and after (A). Each moose was located ("fixed") three times a day, early morning, mid-day and evening, by triangulation from forest roads that criss-cross the area. Based on previous experience it was assumed that a location was accurate to a 100 × 100 m grid square. The manoeuvres (~velse-Elg 94) were carried out throughout most of Amot municipality in mid-September 1994. In total 6000 men, several hundred all-terrain vehicles, battle tanks and self-propelled canons, two wings of attack helicopters, one wing of transport helicopters and four jet fighter squadrons were involved. While most activity was concentrated in the valley bottoms, a large number of units moved around higher ground and the entire area was subjected to repeated low level jet and helicopter overflights. In total nine of the 12 adult moose were exposed to significant levels of military disturbance, while three were outside the main areas and received at most some few high-altitude overflights. At Terningmoen and Songli (Areas 1 and 3) the instrumented moose were fixed before the experimental disturbance occurred. Nine types of stimuli were considered, a cross-country skier, a person on foot, a platoon of soldiers on foot (with small arms firing in two cases), a tracked all-terrain vehicle, a snowscooter, a four-wheel motorcycle, a helicopter, a F-16 fighter jet, and canon fire. For the purpose of analysis these were grouped into two categories, those in which the source of disturbance could be identifed as people per se by the moose (the first three stimuli classes), hereafter called human, and those in which the source would not be regarded as human (the latter six stimuli classes), hereafter called mechanical. In total 40 trials were carried out, 19 human and 21 mechanical. In every case the trial ended when the moose showed a flight response, although not all approaches were close enough to elicit response. The minimum distance of approach, the distance from the disturber at which flight began (the flush distance), and the linear distance covered during flight (the flight distance) was always recorded. The heart rate before disturbance, the maximum heart rate reached and the time for heart rate to return to pre-disturbance levels were recorded in 29 trials.

Military disturbance of moose Analysis For the manoeuvres, home ranges were calculated for each of the three sampling periods. Range size was estimated using two different methods: (1) the minimum convex polygon (MCP) method because of its simplicity and widespread use: and (2) the 95% contour from the adaptive kernel method (Worton, 1989) because of its greater statistical robustness and insensitivity to outliers. The latter method was also used to calculate the centre of activity for each home range. As an index of movement the linear distances (m) between the morning and the evening fixes of the same day, and between the evening and subsequent morning fixes, were calculated. These were then averaged for each animal for each period. Additionally the linear distance between the very first and the very last fix for each tracking period was calculated. All calculations were performed with the R A N G E S IV computer package (Robert Kenward, Institute of Terrestrial Ecology, Wareham, UK). Paired t-tests, two-tailed t-tests with unequal variances and Pearsons correlation were used. All means are presented with standard errors. RESULTS The behaviomal and physiological effects of the stimuli trials The results of the 40 individual disturbance trials are shown in Table 1. There was a clear tendency for all approaches by pedestrian stimuli to elicit flight responses in moose at much greater distances than mechanical stimuli. Even within 100 m only 75% of trials resulted in flight. For further analysis of the difference in response between pedestrian and mechanical stimuli, we considered only those trials in which flight was elicited. Heart rate only increased in those cases in which flight was induced. There was no significant difference in the percentage increase in heart rate (125.9 + 85.4 vs 164.9 + 77.2%, t = 1.02, d.f. = 14,3, p = 0.35) between human and mechanical stimuli, respectively, although the time for the heart rate to return to predisturbance levels was significantly longer after human disturbances (13.9 + 5.0 vs 9.3 + 3-9 min, t -- 2.3, d.f. = 12,5, p = 0,04). There was no significant difference in flight distance between the h u m a n and mechanical stimuli (1147 + 537 vs 857 + 424 m, t -- 1-26, d.f. = 18,6, p = 0.232). The difference in flush distance was significant, however, with human disturbances eliciting flight at much greater distances than mechanical disturbances (211 + 116 vs 58 _+ 35 m, t = 4-81, d.f. = 18,6, p<0.001). Within the pedestrian disturbances there was a significant negative correlation between flush distance and flight distance (r = -0.612, n = 19, p = 0.007), and between flush distance and the time for heart rate to return to normal (r = -0.926, n = 13, p = 0.008). The same trend, although not statistically significant, appeared within the mechanical disturbances for both flush-flight distance (r = -0.708, n -- 7, p -- 0-075) and

171

flush distance-heart rate relationship (r = -0.496, n : 6, p : 0-085).

Movements of moose in ,i.mot before the manoeuvres The mean summer home range size (1993) of eight adult female moose in A m o t from after migration in M a y until the start of the annual moose hunt on 25 September was 11.1 + 1.3 km: (MCP) or 10-3 + 1.4 km 2 (95% kernel), which from the kernel area gives a mean home range diameter (assuming it is circular) of 3.6 km. Five of these eight cows showed a clear spring migration from winter areas to summer areas (greater than a range diameter) in early May. The mean distance migrated for these five cows was 10-9 kin: autumn migration was an indistinct drift in area of activity. For six cows that were present in both samples the mean distance from the centre of the 1993 summer range to that of the 1994 pre-disturbance range was 6.5 + 3 . 5 km. Changes in home range size during the manoeuvres Figure 1 shows the home range size of each of the 12 moose before, during, and after the manoeuvres. While there was much variation in individual response there was a clear trend for home ranges to increase in size during the manoeuvres and then to decrease in size again, apart from bulls 335 and 330 (see Discussion), and cow 280. For the nine disturbed animals the mean MCP home range size during the manoeuvres was significantly greater than the mean of the before and after range sizes (paired t-test: 6.4 + 1.3 km 2 vs 3.7 + 1.1 km 2, t = 2.68, d.f. = 8, p = 0.03) although the equivalent difference was only approaching significance for the kernel estimate (paired t-test: 4.6 + 1.2 km ~ vs 2.5 +_ 0-8 km 2, t = 2-19, d.f. = 8, p = 0-06). In most cases, however, the post-manoeuvres home range did not quite return to the former size within the week of observation. The home range of one of the three peripheral animals (cow 160, Fig. 2) increased rapidly during this period, but the increase in the mean for the entire peripheral group was not significant; (MCP: B 4.8 + l-l, D 7.7 + 3.1, A 5.1 + 3.9 km2: kernel: B 3.2 _+ 0.5, D 6.4 + 2-9, A 3.6 + 1.8 kin2). The exceptional movement of cow 160 was stimulated by a large amount of activity from four hare hunters and their two loose dogs inside her home range for two days, and not to any military activity. The total home ranges of the eight cows in the sample for the three weeks of the disturbance period (before, during and after) were not significantly different from the total summer home ranges of eight cows monitored the previous year (MCP 11.8 vs 11.1 km 2, t = 0.35). Daily movements As there was no significant difference between daily movement vs nightly movement inter-fix distances

R. Andersen, J. D. C. Linnell, R. Langvatn

172

Table 1. Physiological and behavioural responses of radio-collared moose to disturbance stimuli Heart rate before and during flight (beats/min) and time to return to normal (min); minimum approach, flush and flight distances (m).

Disturbance

Sex

Month

Skier Skier Skier Skier Infantry troop Infantry troop Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Pedestrian Infantry troop Infantry troop Mean SD

F F F F F F M M M M M M M M M M M M M

02 02 03 03 03 03 07 07 07 07 07 08 08 08 08 08 09 09 09

Tracked jeep Snowscooter Snowscooter Snowscooter Snowscooter Snowscooter Snowscooter Snowscooter 4WD Motorcycle 4WD Motorcycle Helicopter Helicopter Helicopter Helicopter Helicopter Helicopter 4WD Motorcycle 4WD Motorcycle Jet Cannonfire 4WD Motorcycle Mean SD

F F F F F F F F M M M M M M M M M M M M M

02 03 03 03 03 03 03 03 08 08 08 08 08 08 08 08 08 08 08 09 09

Heart rate (beats/min) Before

Max.

Time to return to normal (min)

30 30

80 95

20 17

50 74 65 70 135 55 60 65 55 52 48 48 46

110 115 95 210 195 105 190 195 110 210 60 70 72

15 15

30

90

13 10 10 7 8 11 15 25 15 13"9 ± 5"0

Minimum distance of approach (m)

Flush distance (m)

100 200 50 40 80 80 400 200 350 200 350 350 70 250 350 120 200 150 200 211 ± 116

100 200 50 40 80 80 400 200 350 200 350 350 70 250 350 120 200 150 200 211 ± 116

9

Flight distance (m) 900 1000 1350 2400 1200 1100 1000 1200 200 950 1200 800 2000 800 600 1400 700 1800 1200 1"147± 537

70

800

5

1200

50

400

70

800

120

300

40

1500

50

1000

70 70 15 100 10 60 50-80 65 80 80 80 50-55 50-55 60 85 70 65 58 54

80 105 80 80 205 55 55 205 85 70 65 58 54

within each o f the three p e r i o d s ( p a i r e d t-tests, d.f. = 11, p >0.05) these were p o o l e d . F o r the nine d i s t u r b e d m o o s e there were no significant differences between periods. These values are actually smaller t h a n the m e a n s for the three p e r i p h e r a l a n i m a l s (B 1.1 + 0.1, D 1.2 + 1.4, A 1.4 + 5.1 km). T h e w i t h i n - p e r i o d linear distance f r o m first to last fix over the three weeks increased significantly; this indicates that the movements increased during the manoeuvres a n d r e m a i n e d h i g h afterwards. T h e m e a n values for the

400 3 400 600 8 500 800 11

9.3 ± 3.9

350 250 150 400 350 321 +_221

~±35

~7±4~

three p e r i p h e r a l a n i m a l s d u r i n g the first a n d third weeks were even higher than for the d i s t u r b e d moose, a l t h o u g h in the third p e r i o d they declined to b e l o w t h a t o f the d i s t u r b e d g r o u p (B 2.3 _+ 0-7, D 3-1 + 1.4, A 1.7 + 0.8 km). Movements of home range centres H o m e range centres o f activity for d i s t u r b e d m o o s e m o v e d a m e a n o f 1.4 + 0.4 k m d u r i n g the m a n o e u v r e s , a n d a further 2.4 _+ 0.2 k m after m a n o u e v r e s , giving a

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Peripheral moose 1614

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Fig. 1.95% kernel and minimum convex polygon home range areas (kin2) for three peripheral and nine disturbed radio-collared moose before (B), during (D) and after (A) military manoeuvres.

mean linear displacement of 3.0 + 0.4 km for the threeweek period. The peripheral moose showed greater variation, but a similar total mean linear displacement

of 3.3 + 2-1 km. The frequency histogram (Fig. 3) shows the frequency distribution of total displacement distances for all moose, where the outlier caused by

R. Andersen, J. D. C. Linnell, R. Langvatn

174

300 I

350

400

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Fig. 2. Examples of the minimum convex polygon home range shifts of four radio-collared moose before (B,--), during (D,- - -) and after (A ..... ) military manoeuvres. Moose 160 was peripheral to the disturbance and the other three were within the disturbed area. The shaded area represents land over 500 m. peripheral cow 160 is clearly shown (displacement 7.5 kin). From this distribution it is apparent that 78% (7 of 9) moose were displaced by less than a mean summer home range diameter. This gradual movement of range centres is mirrored by a decrease in consecutive home range overlap (Fig. 2). After the manoeuvres only 4.5% of the M C P home range overlapped with the original home range, on average. Excluding cow 160 (which had no overlap before and after disturbance) the two peripheral moose had a mean overlap of 27.2%.

ing a response, the greater the flight distance and the time for heart rate to return to normal. This result for

4

--

Z /J

Z f/

3 -O

E .~

Disturbed

moose

2 -f.,

1 --

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<', Z

DISCUSSION

Effects of specific stimuli The clear result from the studies of specific stimuli was that sources of disturbance which can be identified as human in origin trigger flight responses at greater distances, and elevate heart rate for longer periods, than those recognised as mechanical. Also, the closer either stimulus is able to approach the moose before trigger-

,

°t

U

Peripheral m o o s e

I

[

I

I

I

I

I

I

1

2

3

4

5

6

7

8

Displacement

distance

Fig. 3. Frequency histogram of the (km) of the kernel centre of activity three peripheral and nine disturbed before military manoeuvres to the

(kin)

displacement distance~ for the home ranges o: moose, from the wee~ week after it ended.

Military disturbance of moose moose is consistent with other studies on bighorn sheep Ovis canadensis and mule deer Odocoileus hemionus, which have demonstrated greater fear responses to people than to aircraft and snowmobiles, respectively (MacArthur et al., 1982; Freddy et al., 1986). Even the noise of F-16 jets flying (subsonic) at heights of 150 m was not able to elicit any heart rate or activity response from a moose, while skiers and walkers were flushing moose at 2 0 0 4 0 0 m. While flight distances were similar for both forms of disturbance, it should be noted that it was extreme stimuli such as snowscooters being driven to within 5 m, and helicopters flying at 50 m or below, which caused flights in excess of 1 kin, such as were regularly produced by solitary pedestrians. Past experience may be crucial to this behaviour. In Alaska, caribou herds which had the most experience of being hunted from snowscooters and aircraft showed far greater fear responses than herds which had only unthreatening, although much more frequent, experiences with snowscooters and aircraft (Valkenburg & Davis, 1985). This highlights the fact that humans cause disturbance because they are perceived as predators. However, human predation in Norway has been exclusively from hunters on foot. As snowscooters are highly controlled, few if any moose have ever had bad harassment experiences with mechanical stimuli. Should this situation change it would be expected that their response to mechanical disturbances would greatly increase. The ability of ungulates to adapt to people who are confined to predictable areas, activities or routes is clearly shown in studies on the responses of chamois, isard Rupicapra pyreneica and wapiti Cervus elaphus to skiers and hikers (Cederna & Lovari, 1985; Tyler, 1991; Cassirer et al., 1992; Lamerenx et al., 1992), Although these moose received much disturbance from unusual sources, none showed flight distances which would have carried them out of a normal home range; only two flights (both from humans) carried moose >2 km, demonstrating their strong fidelity to home ranges (see Edge et al., 1985).

Effects caused by the manoeuvres The changes in range area from before the manoeuvres to afterwards indicated that the disturbance was having some effect on animal movement. Although morning to evening interfix distances did not increase, the increase in first to last fix distance implies that movements were directional over several days, so that over the period of a week the animals were covering more total area than before. After the manoeuvres most animals reduced their range areas, but not to their pre-disturbance sizes. Several factors may have contributed to their retaining somewhat larger home ranges and greater first to last interfix movements than before. First, those that were slightly displaced may have needed more than a week to return to their normal area. Red deer, for example, required up to four days to return to their normal ranges after being displaced in Denmark (Jeppesen,

175

1987). Secondly, the small game-hunting season began during the manoeuvres, and many hunters with loose dogs entered the woods with the departure of the military. Finally, the moose rut begins in October and the home ranges of moose bulls (especially young bulls) are known to increase in the autumn (Philips et al., 1973; Lynch & Morgantini, 1984; Lorentsen et al., 1991). This is probably the best explanation for the behaviour of bull 335. Only two moose showed any reaction which could be considered as leading them beyond the boundaries of a normal summer home range, which vary from 10-11 km 2 in Amot, to 16 km 2 in the nearby Dokka valley (Andersen, 1991). This may be because they are accustomed to the activities of the forestry industry which uses all-terrain cutting and transporting vehicles throughout the forest to extract timber. These have no direct detrimental effect on moose, and other ungulates such as roe deer Capreolus capreolus appear to ignore their operation (Linnell & Andersen, in press). The extra browse which the offcuts provide in winter may even cause a positive association with vehicle activity. Fears that moose would vacate the area completely because of the disturbance from military activity thus appear unjustified from the data presented here. However, the generality of these results should not be assumed. The same level of disturbance in winter can have more detrimental effects. The mobility of the animals are constrained and more energetically expensive because of snow depth. Additionally, such disturbance of moose in poorer body condition (see Skogland & Grovan, 1988, for reindeer), or at more critical times of the year, such as calving time, could have had far more drastic effects. Nevertheless, it appears probable that moose, like most ungulate species, have the ability to adapt to a human multi-use landscape, in which the military are but one of many users. ACKNOWLEDGEMENTS We are grateful to Alan Bryan, Erling N~ess and Arild Reitan for assistance in radio tracking during the manoeuvres, and to Lt-Col. Bjorn Boye and Major Ola Petter Borg for both logistic and intellectual support. We acknowledge the economical support of the Norwegian Ministry of Defence.

REFERENCES Andersen, R. (1991). Habitat changes in moose ranges: effects on migratory behaviour, site fidelity and size of summer home range. Alces, 27, 85-92. Cassirer, E. F., Freddy, D. J, & Ables, E. D. (1992). Elk responses to disturbance by cross-country skiers in Yellowstone National Park. WildL Soc. BulL, 20, 375-81. Cederna, A. & Lovari, S. (1985). Impact of tourism on chamois feeding activities in an area of the Abruzzo National Park. In The biology and management of mountain ungulates, ed. S. Lovari. Croom Helm, London, pp. 216-25.

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R. Andersen, J. D. C. Linnell, R. Langvatn

Edge, W. D., Marcum, C. L. & Olson, S. L. (1985). Effects of logging activities on home range fidelity of elk. J. Wildl. Manage., 49, 741-4. Freddy, D. J., Bronaugh, W. M. & Fowler, M. C. (1986). Responses of mule deer to disturbance by persons afoot and snowmobiles. Wildl. Soc. Bull., 14, 63-8. Hansen, A. J., Garman, S. L., Marks, B. & Urban, D. L. (1993). An approach for managing vertebrate diversity across multiple-use landscapes. Ecol. AppL, 3, 481-96. Jeppesen, J. L. (1987). Impact of human disturbance on home range, movement and activity of red deer (Cervus elaphus) in a Danish environment. Dan. Rev. Game. Biol., 31, 1-38. Kuck, L., Hompland, G. L. & Merrill, E. H. (1985). Elk calf response to simulated mine disturbance in southeast Idaho. J. Wildl. Manage., 49, 751-7. Kvam, T. & Stensli, O. M. (1991). Registrering av store rovdyr i Mauken og B1Atind vg~ren 1991. NINA Oppdragsmelding, 100, 1-20. Lamerenx, F., Chadelaud, H., Bard, B. & P6pin, D. (1992). Influence of the proximity of a hiking trail on the behaviour of izards (Rupicapra pyrenaica) in a Pyrenean reserve. In Ongul6s/ungulates, ed. F. Spitz, G. Janeau, G. Gonzalez & S. Aulagnier. SFEPM-IRGM, Toulouse, pp. 605-8. Langvatn, R. & Andersen, R. (1991). Stay og forstyrrelsermetodikk til registrering av hjortedyrs reaksjon p~, milit~er aktivitet. NINA Oppdragsmelding, 98, 1-48. Linnell, J. D. C. & Andersen, R. (in press). Site tenacity and logging disturbance in roe deer. Wildl. Soc. Bull. Lorentsen, O., Wiseth, B., Einvik, K. & Pedersen, P. H. (1991). Elg i Nord-Trondelag: resultater fra elgundersokelsene 1987-1990 om vandringsmonster, brunst, kalvinger og dodelighet. Fylkesmannen i Nord-Trondelag Miljovernavdelingen Rapport, 1-1991, 1 208.

Lynch, G. M. & Morgantini, L. E. (1984). Sex and age differential in seasonal home range size of moose in northcentral Alberta, 1971-1979. Alces, 20, 61-78. MacArthur, R. A., Geist, V. & Johnston, R. H. (1982). Cardiac and behavioral responses of mountain sheep to human disturbance. J. Wildl. Manage., 46, 351-8. Philips, R. L., Berg, W. E. & Siniff, D. B. (1973). Moose movement patterns and range use in northwestern Minnesota. J. Wildl. Manage., 37, 266-78. Root, B. G., Fritzell, E. K. & Giessman, N. F. (1988). Effects of intensive hunting on white-tailed deer movement. Wildl. Soc. Bull., 16, 145-51. Skogland, T. & Grovan, B. (1988). The effects of human disturbance on the activity of wild reindeer in different physical condition. Rangifer, 8, 11-9. Stockwell, C. A. & Bateman, G. C. (1991). Conflicts in National Parks: a case study of helicopters and bighorn sheep time budgets at the Grand Canyon. Biol. Conserv., 56, 317-28. Tyler, N. C. (1991). Short-term behavioural responses of Svalbard reindeer Rangifer tarandus platyrhynchus to direct provocation by a snowmobile. Biol. Conserv., 56, 179-94. Valkenburg, P. & Davis, J. L. (1985). The reaction of caribou to aircraft: a comparison of two herds. In Caribou and

human activity. Proceedings of the 1st North American Caribou Workshop, ed. A. M. Martell & D. E, Russell. Whitehorse, Yukon, pp. 7-9. Wiens, J. A. (1990). Habitat fragmentation and wildlife populations: the importance of autecology, time and landscape structure. Trans. Int. Un. Game Biol. Congr., 19th, ed. S. Myrberget. Trondheim, Norway, pp. 381-91~ Worton, B. J. (1989). Kernel methods for estimating the utilization distribution in home range studies. Ecology, 70, 164-8.