Mountain hares Lepus timidus and tourism: Stress events and reactions

Abstract

Winter tourism in the European Alps has developed rapidly over the past few decades, leading to the expansion of ski resorts, growing numbers of visitors and a massive increase in snow sport activities such as free-ride skiing and snowboarding, backcountry skiing and snowshoeing. Wildlife is often disturbed by these largely unpredictable activities, and animals may have limited opportunities to adapt. Mountain hares Lepus timidus are affected by this increase in alpine tourism, but their physiological and behavioural reactions to tourist activity are still unknown.We measured the levels of faecal glucocorticoid metabolites (GCM) in wild mountain hares living in areas that had no, medium or high levels of tourist activity during winter in 2011. Furthermore, we compared the changes in GCM excretion, behaviour and food intake of six captive mountain hares following predator challenge experiments from early to mid-winter.Our field results showed that GCM excretion is positively correlated with increased tourism intensity. In the predator challenge experiments, hares spent less time resting and grooming (including re-ingesting faecal pellets) during and after the stress treatments. These stress events lead to higher energy demands due to flushing, increased GCM levels, and disrupted the energy intake that hares derive from faeces.We conclude that mountain hares living in areas with frequent human winter recreational activities show changes in physiology and behaviour that demand additional energy in winter, when access to food resources is limited by snow.Synthesis and applications. To bring down the frequency of stress threats for mountain hares, we recommend that managers keep forests inhabited by mountain hares free of tourism infrastructure and retain undisturbed forest patches within skiing areas. Other species such as black grouse Tetrao tetrix and/or capercaillie Tetrao urogallus are also likely to benefit from such management activities because they share similar habitat requirements with mountain hares.

Full text

Mountain hares Lepus timidus and tourism: stress
events and reactions
Maik Rehnus
1,2
*, Martin Wehrle
3
and Rupert Palme
4
1
Swiss Federal Research Institute WSL, Z€
urcherstrasse 111, 8903 Birmensdorf, Switzerland;
2
Institute of Wildlife
Biology and Game Management, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Str. 33,
1180 Vienna, Austria;
3
Natur- und Tierpark Goldau, Parkstrasse 26, 6410 Goldau, Switzerland; and
4
Department of
Biomedical Sciences/Biochemistry, University of Veterinary Medicine, Veterin€
arplatz 1,1210 Vienna, Austria
Summary
1. Winter tourism in the European Alps has developed rapidly over the past few decades,
leading to the expansion of ski resorts, growing numbers of visitors and a massive increase in
snow sport activities such as free-ride skiing and snowboarding, backcountry skiing and
snowshoeing. Wildlife is often disturbed by these largely unpredictable activities, and animals
may have limited opportunities to adapt. Mountain hares Lepus timidus are affected by this
increase in alpine tourism, but their physiological and behavioural reactions to tourist activity
are still unknown.
2. We measured the levels of faecal glucocorticoid metabolites (GCM) in wild mountain
hares living in areas that had no, medium or high levels of tourist activity during winter
in 2011. Furthermore, we compared the changes in GCM excretion, behaviour and food
intake of six captive mountain hares following predator challenge experiments from early to
mid-winter.
3. Our field results showed that GCM excretion is positively correlated with increased tour-
ism intensity. In the predator challenge experiments, hares spent less time resting and groom-
ing (including re-ingesting faecal pellets) during and after the stress treatments. These stress
events lead to higher energy demands due to flushing, increased GCM levels, and disrupted
the energy intake that hares derive from faeces.
4. We conclude that mountain hares living in areas with frequent human winter recreational
activities show changes in physiology and behaviour that demand additional energy in winter,
when access to food resources is limited by snow.
5. Synthesis and applications. To bring down the frequency of stress threats for mountain
hares, we recommend that managers keep forests inhabited by mountain hares free of tourism
infrastructure and retain undisturbed forest patches within skiing areas. Other species such as
black grouse Tetrao tetrix and/or capercaillie Tetrao urogallus are also likely to benefit from
such management activities because they share similar habitat requirements with mountain
hares.
Key-words: Alps, behaviour, cortisol, faeces, non-invasive, Lepus timidus, tourism
Introduction
Winter tourism in the European Alps has developed
rapidly over the past few decades, leading to the expansion
of ski resorts, growing numbers of visitors and a massive
increase in snow sport activities such as free-ride skiing
and snow-boarding, backcountry skiing and snowshoeing
(Ingold 2005; Schweizer Alpen-Club 2012). Thus, in
addition to predictable environmental conditions such as
seasonal changes in climate and resource availability, wild
animals must also cope with unpredictable levels of human
disturbance (Wingfield & Romero 1999; Taylor & Knight
2003; Ingold 2005). Expansions in tourist activities that
increase pressure upon biodiversity (Czech, Krausman
& Devers 2000; Watson & Moss 2004; Arlettaz et al. 2007;
Barja et al. 2007; Ellenberg et al. 2007) and lead to habitat
loss and degradation can elicit costly behavioural
responses in animals (Lott & McCoy 1995; Fernandez-
Juricic & Telleria 2000; Sapolsky, Romero & Munck 2000;
*Correspondence author. E-mail: maik.rehnus@gmx.de
©2013 The Authors. Journal of Applied Ecology ©2013 British Ecological Society
Journal of Applied Ecology 2014, 51, 6–12 doi: 10.1111/1365-2664.12174

Mar
echal et al. 2011). Even in the absence of behavioural
reactions, the presence of humans may evoke a physiologi-
cal stress response (Stillman & Goss-Custard 2002;
Walker, Boersma & Wingfield 2005; Arlettaz et al. 2007;
Thiel et al. 2008), with chronically elevated stress levels
affecting metabolism, immune response, reproduction and/
or survival (Boonstra et al. 1998; Sapolsky, Romero &
Munck 2000; Sheriff, Krebs & Boonstra 2009; Clinchy
et al. 2011). Both physiological and behavioural responses
are often combined with extra energetic costs (Baltic et al.
2005), especially during winter when most wildlife species
face an energy bottleneck. Nevertheless, the physiological
and behavioural reactions of mountain hares Lepus timidus
to tourist activities are still unknown.
Non-invasive methods for measuring steroid hormone
metabolites in the faeces have become a widely accepted
tool to assess the endocrine status of animals, especially
free-ranging animals (Palme 2005; Sheriff et al. 2011).
The advantage of such methods is that samples can be
collected easily without any need to handle the animal.
The methods are therefore appropriate for evaluating
adrenocortical activity in wild animals.
In this study, we measured the levels of glucocorticoid
metabolites (GCM) in mountain hares in areas with dif-
ferent tourist intensities during winter. We also investi-
gated the influence of predator challenge experiments on
GCM excretion, behaviour and food intake. Finally, we
suggest management strategies for conserving mountain
hare populations in the Alps.
Materials and methods
FIELDWORK
To study the effect of different levels of tourism on mountain
hares, we selected three sites in south-eastern Switzerland based
on their proximities to one another and their tourist activities in
2011. The ski region Lagalp (46°25′N, 10°00′E, 2079–2905 m
a.s.l.) represents an intensively (=high) used region with 227 22
visitors per day on 1 km of ski trail; the ski region Minschuns
(46°38′N, 10°19′E, 2075–2700 m a.s.l.) received moderate (=med-
ium) use with 125 6 visitors per day on 1 km of ski trail; and
the Swiss National Park (46°39′N, 10°11′E, 1897–2201 m a.s.l.) is
closed to tourism (=zero; not frequented) in the winter. The cli-
mate in the region is continental and comparable between all
three sites. As measured over three decades at the Buffalora
weather station at 1970 m a.s.l. (Aschwanden et al. 1996), the
mean winter temperature for the region is 92°C and the mean
precipitation is 54 mm.
Faecal samples were collected over transects with a total length
of 429 km (high =180 km, medium =186 km and zero
=63 km) and altitudinal differences of 900 m between January
and March 2011 (outside the breeding season of mountain hare).
We collected samples close to places with tourist activities (if
available within 100 m of source), and the accessibility (danger of
avalanches) was taken into consideration. We randomly searched
for potential locations for faeces at each site (distinctive stones
and trees, locations with mountain hare tracks), cleared them of
all mountain hare faeces and marked them with GPS. Three
nights later, plots were revisited and fresh samples (one sample
consisted of a minimum of three pellets) were collected as recom-
mended by Rehnus, Hackl€
ander & Palme (2009).
In total, 132 faecal samples were collected (high =33,
medium =46 and zero =53). The altitude of each location and
the type of the nearest tourist activity (‘ski’, ‘snowshoe’ and
‘cross-country skiing’) and its distance to the faeces were deter-
mined. As the mountain hare has been shown to be the only spe-
cies of hare in these three study sites (Rehnus et al. 2010, 2013;
D. Godli & J. Gross, personal communication), our sampled fae-
ces could not have been confused with faeces from European
hares, Lepus europaeus.
STRESS EXPERIMENTS
In general, humans as hikers in wildlife habitats are recognized as
potential predators (Beale & Monaghan 2004). We used predator
challenge experiments to investigate their potential effects on GCM
excretion, behaviour and food intake in six mountain hares by
comparing periods of stress and non-stress (for details see Table 1).
Animals were kept in aviaries (6–12 m
2
) in a separate hall that
was protected against all hare predators. Mean air temperature
(in the morning) in the hall was 7203°C (range 2–12 °C).
We used a trained dog (without barking or whining) and a kite
with a wingspan of 18 m as simulated terrestrial and avian pre-
dators. Both simulate natural predators of the mountain hare
such as the fox Vulpes vulpes and the golden eagle Aquila chrysae-
tos (Thulin & Flux 2003). The hares in the stress aviaries were
separated from those in the control aviaries by a dark green cloth
and a 5-m corridor. The dog (walking and sniffing around the
aviaries) or kite (flying over the aviaries) was taken to each stress
aviary for 1–2 min every other day. To ensure habituation did
not occur (Dallman & Bhatnagar 2001), stressors were used at
various times throughout the day and the order of exposure was
randomized. Control hares had no contact, visual or physical,
with the stressors. Although they may have smelled the dog, con-
trol hares did not alter their behaviour during stress exposure
(Sheriff, Krebs & Boonstra 2009). The same stressors were used
throughout the experiment.
Fresh samples (with a minimum of five pellets) were collected
each morning while cleaning the aviaries. On days with a preda-
tor challenge, additional samples were collected 8 hours after the
simulation. Thus, samples collected after 8, 24 and 48 hours were
available to estimate individual peaks of GCM levels after stress
simulation (Rehnus, Hackl€
ander & Palme 2009).
To detect the changes in relative amounts of a particular type
of behaviour over the course of a day, we compared control and
stressed hares over a 24-hour period. Activities were recorded by
a video camera (Monacor IP65) that allowed observation during
day and night. We observed each individual for four 24-hour
periods, where 2 days were in the stress period (days with simula-
tion) and two in the non-stress period. Usually records started
early in the morning and ended at the same time the next day.
As a result of randomized simulations during daytime, time
between start of recording and initial simulation differed. Behav-
iour activities were analysed by the software CowLog (H€
anninen
& Pastell 2009). We classified the behaviour of hares based on a
literature review (Schneider 1978; Hewson 1990a; Wolfe & Long
2002) as follows: Feeding (feeding activities at available food
boxes and hay place), Canopy (hare under natural canopy in its
©2013 The Authors. Journal of Applied Ecology ©2013 British Ecological Society, Journal of Applied Ecology,51,6–12
Stress responses of mountain hares to tourism 7

aviary), Resting (resting and sleeping in open areas), Moving
(movements in open areas to/from canopy and/or to/from feeding
places) and Grooming (grooming in open areas, coprophagy). In
grooming, we also included potential re-ingestion activities,
because coprophagy could not always be definitively distinguished
from some grooming activities from the fixed camera images.
To investigate food intake (gross MJ per day) during different
periods, we measured the food weight (mix of Provacca chips,
standardized mountain hare mix including lucerne pellets and hay
from alpine meadows) given to the hares before and after each
24-hour period (n=118).
To ensure an adequate state of health for each hare during the
experiment, we regularly checked faecal samples for endoparasites
and took blood samples to check various health parameters (min-
eral nutrients, protein, creatinine, cholesterol, etc.). When a hare
experienced a coccidial infection (each hare up to three times), we
used Toltrazuril over three consecutive days. Faeces collected
during periods of infection were not used for analysis because
infection can increase the GCM levels (Sheriff et al. 2011).
ANALYSIS OF FAECAL CORTISOL METABOLITES
To measure faecal GCM, we used an 11-oxoaetiocholanolone
enzyme immunoassay (EIA) previously shown as being suitable
for evaluating adrenocortical activity in mountain hares (Rehnus,
Hackl€
ander & Palme 2009). Details of the extraction procedure
and the EIA can be found elsewhere (M€
ostl et al. 2002; Rehnus,
Hackl€
ander & Palme 2009; Palme et al. 2013).
Data analysis
All statistical tests were conducted using R 2131 (R Develop-
ment Core Team 2010).
FIELDWORK
Faecal samples were classified according to the intensity of tour-
ism: high (Lagalp), medium (Minschuns) and zero (SNP). The
Shapiro–Wilk normality test showed that the frequencies of visi-
tors to the two study sites (February to March 2011) were nor-
mally distributed, and a t test was used to determine differences
in frequencies. Influences on the GCM concentration were tested
using variance analysis with the GCM concentration as a depen-
dent variable and the site as a predictor variable. Differences
between sites were evaluated with a Tukey test for post hoc test-
ing. In the same way, we tested the potential influence of distance
and type of activity (ski/snowboard, snowshoe and cross-country
skiing) on GCM concentration.
STRESS EXPERIMENTS
To test the effect of stress simulation on GCM levels, behaviour
classes and food intake, we compared two models, with and with-
out the simulation, with likelihood-ratio tests and hare as a
repeated measure. Before analysis, we evaluated linear mixed
models by their residuals (including residual plots). We did not
include temperature as a potential explanatory variable (Flux
1970; Rehnus et al. 2010) because it did not change significantly
during experiments (t tests: t =05387, d.f. =19521, P=059).
To investigate the influence of the predator challenge experi-
ments on GCM level, we initially determined individual delay
times of GCM excretion. Individual differences were found in the
peaks after simulation (8 and 24 hours after treatment). In fur-
ther statistical analyses, we used only samples reflecting peak
GCM production of individuals. Thus, the original sample size
was reduced by 64% from 589 to 219 samples.
Results
FIELDWORK
Concentrations of GCMs in faecal samples of mountain
hares varied significantly across study areas (F
2,132
=436,
P=001). As revealed by post hoc tests, faecal GCM
values were higher (P<005) at the site with high tour-
ist activity than at the other two sites (Fig. 1). Within
Table 1. Chronology of the stress experiment carried out on six mountain hares from October 2011 to January 2012
Date Group* Treatment Procedure (Sample collection times)
October 13 1, 2 Moving to the experimental study site and blood sampling
October 13–23 1, 2 Acclimatization Monitoring of GCM excretion (5 924 hours per week per hare),
behaviour (2 924 hours per hare), food intake (2 days per week
per hare), endoparasites (19per week)
October 24–November 24 1 Predator challenge (random
stressor at various times)
Monitoring of GCM excretion (5 924 hours per week and hare
and an 8-hour sample per hare after threat), behaviour
(2 924 hours per hare), food intake (2 days per week per hare),
endoparasites (19per week)
October 24–November 24 2 No stress simulations Monitoring of GCM excretion (5 924 hours per week per hare),
behaviour (2 924 hours per hare), food intake (2 days per week
per hare), endoparasites (19per week)
November 25 1, 2 Blood sampling
November 26–December 4 1, 2 Recovery As above (acclimatization)
December 5–January 9 1 No stress simulations As above
December 5–January 9 2 Predator challenge (random
stressor at various times)
As above
January 10–30 1, 2 No stress simulations As above
January 30 1, 2 Blood sampling
*Each group consisted of three mountain hares.
©2013 The Authors. Journal of Applied Ecology ©2013 British Ecological Society, Journal of Applied Ecology,51,6–12
8M. Rehnus, M. Wehrle & R. Palme

touristically frequented areas, frequencies of tourists were
different (t test: t =4468, d.f. =54488, P<0001) but
GCM concentrations were not influenced by the type of
activity (F
2,78
=001, P=096) or by the distance of the
activity to the site of collection of faeces (F
1,78
=181,
P=017).
STRESS EXPERIMENT
We found a significant influence of stress simulation on
GCM levels (likelihood-ratio test: v
2
=82878, d.f. =1,
touristically =001). GCM concentrations increased after
simulation (mean SD: 672190ngg
1
) compared
with days without stress simulation (504125ngg
1
).
The maximum increase above baseline was up to fourfold
(Table 2).
The predator challenge had a significant influence on
the behaviour grooming (likelihood-ratio test: v
2
=
45672, d.f. =1, P=003) and resting (v
2
=36526,
d.f. =1, P=005), while moving (v
2
=00375, d.f. =1,
P=085), feeding (v
2
=03392, d.f. =1, P=056) and
canopy (v
2
=14481, d.f. =1, P=022) did not differ.
Grooming and resting decreased after simulation
(Mean SD: grooming: 4023% and resting: 268
142% of a 24-hour period) compared with days with-
out the stressor (grooming: 5431%, resting:
324144% of a 24-hour period; Fig. 2).
We found a significant influence of stress simulation on
food intake (likelihood ratio test: v
2
=5325, d.f. =1,
P<0001). Food intake increased after simulation
(mean SD: 318 029 MJ day
1
) compared with days
without stress simulation (260 036 MJ day
1
).
0
40
80
120
160
high medium zero
GCM [ng g–1 faeces]
Tourist intensity
n = 33 n = 46 n = 53
Fig. 1. Concentrations of faecal glucocorticoid metabolites
(GCM, mean SE; n=132) of mountain hares in areas with
different levels of tourist activity in Switzerland in winter 2011.
The Tukey test showed differences between the area with the
highest activity and the areas with medium (t =22364, P=004)
and no tourist activity (t =26901, P=001).
Table 2. Stress challenge: individual baseline and peak values
(ng/g faeces; percentage increase) of faecal GCM concentrations
after predator challenge (dog/kite) analysed by the 11-oxoaetio-
cholanolone EIA (n=219)
Animal
Baseline
(Mean SD)
After stress simulation
Maximum (ng g
1
) % Increase
14511 160 354
24912 91 186
34313 72 167
44111 99 245
5639 97 152
65310 81 154
28·6 ± 20·3%
26·8 ± 13·6%
23·9 ± 4·6%
16·6 ± 3·9%
4·0 ± 2·3%
22·4 ± 18·7%
32·4 ± 14·4%
23·4 ± 8·8%
16·2 ± 6·1%
5·4 ± 3·1%
(a)
(b)
Fig. 2. Relative duration (mean SD) of each class of behaviour
(clockwise: black =canopy, checked =feeding, white =moving,
dotted =grooming, grey =resting) in a) control hares (n=12)
and b) stressed hares (n=12).
©2013 The Authors. Journal of Applied Ecology ©2013 British Ecological Society, Journal of Applied Ecology,51,6–12
Stress responses of mountain hares to tourism 9

Discussion
FIELDWORK
Our results showed that GCM excretion is positively cor-
related with increased tourist activity. This result is in
accordance with findings from studies on other wildlife
species. For example, black grouse Tetrao tetrix and cap-
ercaillies Tetrao urogallus had higher GCM levels due to
increased human recreation activities during the winter
(Arlettaz et al. 2007; Thiel et al. 2008, 2011) and birds
flushed from their snow burrows showed increased con-
centrations of faecal corticosterone metabolites (Arlettaz
et al. 2007). In red deer Cervus elaphus and wolves Canis
lupus snow-mobile activity and glucocorticoid metabolites
in the faeces were also positively correlated (Creel et al.
2002). Nevertheless, increased GCM levels should be
interpreted with caution. The stress axis plays a key part
in allowing animals to respond to changes and challenges
in the face of environmental certainty and uncertainty
(Boonstra 2013a), and as a consequence, life-history deci-
sions (e.g. to reproduce, to grow or to put energy into
storage) are implemented (Ricklefs & Wikelski 2002). On
the one hand, short-term glucocorticoid secretion is
related to the adaptive response of animals to stressors
and is beneficial, because glucocorticoids facilitate energy
mobilization and behavioural changes (Boonstra et al.
1998; Wingfield & Romero 1999; Arlettaz et al. 2007;
Thiel et al. 2008). On the other hand, chronically elevated
GCM secretion may lead to a pathological status (Munck,
Guyre & Holbrook 1984; Stewart 2003) and may reduce
both survival and reproductive success (Sapolsky 1992;
M€
ostl & Palme 2002; Arlettaz et al. 2007; Ellenberg et al.
2007; Thiel et al. 2011; Sheriff et al. 2012), although no
such increases in pathology were found in snowshoe hares
Lepus americanus (Boonstra 2013b). Boonstra (2013b)
discussed the possibility that an environment with high
predation risk (elevated GCM levels in animals) leads to
a decrease in reproductive success (Sheriff, Krebs &
Boonstra 2009), while surviving offspring have higher
vigilance and anti-predator behaviour. Thus, hares may
make a trade-off between reproduction and survival
(Boonstra 2013b). We interpret our results as a first
indication of a higher risk of such a shift in mountain
hares that are exposed to tourist activities.
STRESS EXPERIMENTS
Our predator challenges increased hares’ GCM concentra-
tions up to fourfold compared with baseline. Peaks were
reached between 8 and 24 hours after treatment, depend-
ing on the individual hare, which is in line with previously
reported results for the species (Rehnus, Hackl€
ander &
Palme 2009). Interestingly, we observed that the female
hares failed to reproduce following our stress experiment,
in agreement with the study by Sheriff, Krebs & Boonstra
(2009) that found a link between elevated GCM levels
and a decline in reproductive output of free-ranging snow-
shoe hares. We postulate that higher GCM levels during
the winter may negatively affect the reproduction of wild
mountain hares in the subsequent breeding season.
Under control conditions, hares behaved similarly to
those in other studies (Hewson 1962; Lemnell & Lindl€
of
1981; Wolfe & Long 2002). However, stress treatments
lead to changes in the behaviour of wildlife (Lott &
McCoy 1995; Fernandez-Juricic & Telleria 2000;
Mar
echal et al. 2011). Animals exposed to tourist activi-
ties tend to move and stay under the canopy (Treves &
Brandon 2005). Similarly, during stress periods, our cap-
tive hares rested less in open areas (close to shelter
resources) and stayed more under the canopy, leading to
a reduction in grooming and resting times in open areas.
Hares are well equipped to detect approaching predators
visually and acoustically and to escape by running, and
may therefore flee from predators they can see, with
escape more likely than from those that are recognized by
scent but unseen (Hewson 1990b). This behaviour reduces
energy demands through the avoidance of direct contact
with predators. Another way to escape predation is to
move into areas of denser cover, although these are asso-
ciated with a lower quality of food (Hik 1995). Further-
more, visual monitoring of humans (vigilance) and/or
spending more time under the canopy may reduce hares’
ability to detect predators or other threats.
Mountain hares and other leporids have been observed
to re-ingest hard and soft faeces excreted during daytime
rest (Hewson 1962; Flux 1970; Pehrson 1983; Hirakawa
1994, 1996; Thulin & Flux 2003). Such activities were sig-
nificantly decreased after stress simulation in our captive
hares. The interruption and prevention of coprophagy is
associated with a disturbance in digestion and a higher
risk of diarrhoea in domestic rabbits (Proto 1968; Laplace
& Lebas 1977). Furthermore, the growth rate of rabbits
was reduced when they were denied access to caecotro-
phes and feed conversion was reduced in comparison with
rabbits given access to caecotrophes (Robinson, Cheeke &
Patton 1985; Kamphues et al. 1986; Robinson et al. 1986;
Phiny & Kaensombath 2006). Thus, stress events decrease
the time hares spend in safe resting positions where they
can re-ingest faecal pellets and reduce the energy hares
derive from faecal pellets.
We found higher food intake after stress treatments (up
to one fifth of the total daily food intake), which must be
compensated from available food resources during other
times. In our experiments, we provided food ad libitum.
However, additional food resources are not always
available during winter in the wild (Rehnus et al. 2013).
Differences between available food and energy demands
probably contribute to a reduced body condition of hares
in the wild. Malnutrition and low temperatures interact
strongly with predation to influence mortality (Keith et al.
1984). After predator challenges, we found higher GCM
levels than in non-stressed periods, which can also lead to
higher energy needs (Baltic et al. 2005).
©2013 The Authors. Journal of Applied Ecology ©2013 British Ecological Society, Journal of Applied Ecology,51,6–12
10 M. Rehnus, M. Wehrle & R. Palme

During winter with limited food resources, wild animals
minimize energy expenditure by reducing their spatial and
temporal activity. The energy saving is disrupted by
behavioural changes due to predation threats through
movement from resting place to canopy, which can addi-
tionally increase energy demands. However, we did not
find that the time used for feeding differs between days
with and without treatments, as has been described for
other species (Lott & McCoy 1995; Fernandez-Juricic &
Telleria 2000). We assume that this discrepancy relates to
the natural behaviour of hares, which mostly use open
fields or grassland when active at night (Tapper & Barnes
1986) to minimize predation risk (Hik 1995).
The observed increase in food intake in captive hares
can be explained by the direct energetic costs of flushing
and increased GCM levels, as well as by indirect factors
such as disruption of re-ingestion and the consequent
loss of energy that hares derive from faeces. Such differ-
ences cannot be compensated by hares in the wild, which
have limited access to additional food resources in win-
ter. In addition, captive hares did not change their
behaviour for searching for food to minimize the risk of
predation.
MANAGEMENT IMPLICATIONS
The findings of our field study and stress experiments
showed that human recreational activities in winter and
simulated predator challenges lead to higher GCM levels
and behavioural changes in mountain hares. Although
further studies are needed, we recommend decreasing
the frequency of stress threats for mountain hares, keep-
ing forests inhabited by mountain hares free of tourism
infrastructure and retaining undisturbed forest patches
within skiing areas. The creation of new skiing areas
should be avoided in mountain hare habitats, and exist-
ing sites should not be further developed. Regulations
in areas where mountain hare habitats overlap with
human winter recreational activities should stipulate that
tourists stay on the marked trails. In areas with low
connectivity to other populations of mountain hare or
with low numbers of hares, trails should be closed or
relocated to reduce the extent of disturbance. Other
species such as black grouse and/or capercaillie are also
likely to benefit from such management activities
because they share similar habitat requirements with
mountain hares.
Acknowledgements
We thank the Swiss National Park for granting permission to conduct the
study; all helpers from Natur- und Tierpark Goldau for their support in
conducting the experiment; Edith Klobetz-Rassam (Department of Bio-
medical Sciences/Biochemistry, University of Veterinary Medicine, Vienna)
for assistance in the laboratory, the Bristol Foundation for financial sup-
port and Marc Cadotte, Paul Lukacs, Graham Tebb and three anonymous
reviewers for constructive and insightful comments on this manuscript.
The animal experiments were conducted with the permission of the Veteri-
nary Office of the Urkantone in Switzerland (SZ-03/11).
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Handling Editor: Paul Lukacs
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12 M. Rehnus, M. Wehrle & R. Palme