Behavioral Ecology
doi:10.1093/beheco/ars110
Advance Access publication 14 August 2012
Original Article
Solomon A. Tadesse and Burt P. Kotler
Mitriani Department for Desert Ecology, Blaustein Institutes for Desert Research, Ben-Gurion University
of the Negev, Midreshet Ben-Gurion 84990, Israel
Behavioral indicators can provide critical information to conservation managers. Here we apply behavioral indicators based on
foraging theory to quantify the effect of tourists on the critically endangered Nubian ibex (Capra nubiana). Ibex are habituated
to human presence in En Avdat National Park, Israel; nevertheless, they exhibit heightened wariness of humans especially during the kidding season or when far from escape terrain. We applied behavioral indicators through the measurement of givingup-densities (GUD, the amount of food that a forager leaves behind in a resource patch) and vigilance behavior to investigate
the spatial and temporal variation in the patch use behavior of Nubian ibex under the influence of tourism. We hypothesized
that Nubian ibex should treat the presence of tourists in a similar matter to the risk of predation. Our results show that the
impact of tourism on ibex significantly varied both temporally and spatially in response to tourist activity. In regard to the temporal variation, ibex had higher GUDs on weekends when tourist activity was high than on weekdays. Furthermore, ibex GUDs
were highest in the habitat most frequented by tourists, but only at times of high tourist activity. In a second experiment, the
presence of tourists in close proximity always caused Nubian ibex to increase their GUDs in resource patches, even on a steep
slope. The spatial position of the tourists up slope or down slope from the ibex affected both GUDs and vigilance behavior. The
response was especially sharp when the tourists disturbed ibex from up slope, blocking escape lines. Even for this apparently
well-habituated population of ibex, tourist presence significantly increased foraging costs as revealed by behavioral indicators.
This study demonstrates how applying methods from behavioral ecology to conservation problems allows access to useful information that may be difficult to obtain using other approaches. Key words: behavioral indicators, conservation, foraging costs,
giving-up-densities, spatial and temporal variations, tourist presence, vigilance behavior [Behav Ecol].
Introduction
A
forager should exploit a foraging patch according to
patch quality as well as related costs and benefits of foraging (e.g., Brown 1988, 1992; Hochman and Kotler 2006a,
2006b). Consequently, it should leave a resource patch when
its harvest rate falls to equal its energetic, predation, and
missed-opportunity costs of foraging. So, measuring patch use
of a forager can reveal its costs and benefits from foraging
(Kotler et al. 1994). Behavioral indicators of patch use such
as the giving-up-density (GUD, the amount of food that a
forager leaves behind in a resource patch when it leaves the
patch) can thus be used to reveal the role of environmental
factors and the significance of energy, nutrients, and predation risk as inputs to fitness (Tilman 1982; Kotler et al. 1993).
GUDs are often used to measure foraging efficiencies and
landscapes of fear for different prey species foraging in their
natural environment (Brown and Kotler 2004). For example,
Druce (2005) used GUDs in experimental food trays to measure the landscape of fear for Klipspringer (Oreotragus oreotragus) and Rock Hyrax (Procavia capensis), and Kotler et al.
(1994) showed that Nubian ibex (Capra nubiana) extract
more foods from safe patches than they do from risky patches.
Address correspondence to Solomon A. Tadesse. E-mail: tadesse@
bgu.ac.il.
Received 27 December 2011; revised 29 May 2012; accepted 7 June
2012.
© The Author 2012. Published by Oxford University Press on behalf of
the International Society for Behavioral Ecology. All rights reserved.
For permissions, please e-mail: [email protected]
Tourism based on free-ranging wild animals is one of the
most rapidly growing sectors of the travel industry (Otley
2005), leading to growing tourism pressure and associated
impacts on wildlife worldwide (e.g., Klein et al. 1995; Burger
and Gochfeld 1998; Lindsay et al. 2007). These impacts
include continuous and rapid human modification of natural environments even in protected wildlife areas (Morris and
Kingston 2002) and ever greater levels of contact between
humans and wildlife (Manor and Saltz 2003).
The risk-disturbance hypothesis proposes that human
disturbance is analogous to predation risk (Frid and Dill
2002; Gilroy and Sutherland 2007). Consequently, human
disturbance should lead to responses similar to that of actual
predation risk. For example, human activities in natural
areas are known to influence wildlife breeding, habitat use,
nest site selection, and foraging behavior (e.g., Lindsay et al.
2007), and Barnes et al. (1997) found that overall elephant
density in Gabon was inversely related to human activity. This
implies that individuals trade off foraging and antipredator
behaviors in relation to predation risk (Lima and Dill 1990;
Brown and Kotler 2004).
Some ecologists have questioned whether behavioral ecology has anything to offer conservation biology (e.g., Caro
2007). Recently, however, Berger-Tal et al. (2011) noted that
behavioral studies in conservation are extensive. These studies follow 3 themes, including the application of behavioral
indicators. Behavioral indicators based on foraging theory
have many advantages. They are often fast, inexpensive, and
Editor’s choice
Impact of tourism on Nubian Ibex
(Capra nubiana) revealed through assessment
of behavioral indicators
1258
simple to implement. But more importantly, they provide
answers from the forager’s perspective rather than ours,
and they have the potential to provide leading indicators of
change (Kotler et al. 2001; Morris et al. 2009).
Here, we applied behavioral indicators to a herd of apparently well-acclimated Nubian ibex for the purpose of assessing
the impact of humans. We hypothesized that the impacts of
tourism presence on the patch use behavior of Nubian ibex
will vary depending on the landscape and habitat types that
Nubian ibex occupy specifically at the time of human visitations, which can be assessed by measuring GUDs and vigilance behaviour. Perceived predation risk can be indicated
by higher GUDs and the amount of vigilance (Hochman and
Kotler 2006a). Ibex should treat the presence of tourists in
a similar matter to the risk of predation. In effect, tourists
should lead ibex to increase vigilance and to leave resource
patches at higher GUDs.
METHODS
The study species
The critically endangered Nubian ibex (Capra nubiana) are
relatively mobile, stout, sexually dimorphic social animals
that are distributed throughout the central highlands of the
Negev Desert of Israel. They segregate into single sex herds of
adult males or females outside the breeding season in which
individual activity time budgets are similar and synchrony of
activities are generally high (Kohlmann et al. 1996; Tadesse
and Kotler 2010; Tadesse and Kotler 2011). The mass of an
adult Nubian ibex ranges between 25 and 70 kg (Stuart and
Stuart 2000), with males larger and heavier than females
(Gross et al. 1995). As females care for the young, they often
seek habitat that is relatively safe from predation for their offspring (Muller et al. 1995; Tadesse and Kotler 2011). Nubian
ibex are extremely agile in steep terrain. They are primarily
animals of open rocky-desert habitats of rough, dry areas with
abundant cliffs and mountainous terrain. Nubian ibex exhibit
gender differences in diet and habitat selection, which results
in part from gender dependent scaling of gut size and metabolism with body size (Demment 1983). The main predators
of Nubian ibex are leopards (Panthera pardus), striped hyenas
(Hyaena hyaena), and wolves (Canis lupus) (Hochman and
Kotler 2006b), with kids being susceptible to predation by
eagles and bearded vultures (Gypaetus barbatus) (Gross et al.
1995; Stuart and Stuart 2000).
Nubian ibex are habituated to human presence in En
Avdat National Park, Israel. Wildlife habituation to humans
might be observed when the frequency, duration, and type of
intrusion from visitors are regular and predictable (Yorio and
Boersma 1992). Nubian Ibex exhibit heightened wariness of
humans during the kidding season or when far from escape
terrains (Kotler et al. 1994; Muller et al. 1995; Hochman and
Kotler 2006b). During hours of heavy human presence, most
Nubian ibex leave Avdat Canyon (i.e., a habitat between the
steep rocky hills), but return before nightfall (Muller et al.
1995; Shkedy and Saltz 2000). In addition, the use of a nursery by females with lactating young may be promoted by
disturbances associated with human visitation (Muller et al.
1995).
The study area
The study was carried out in the central highlands of the
Negev Desert, Israel (30°52′N, 34°46′E) near Sede Boqer and
in the vicinity of En Avdat National Park. The area is characterized by varied topography whose elevation ranges from
320 to 580 m above sea level. The area is known for its dry
Behavioral Ecology
riverbeds and steep walled hills. It has a dry and warm summer climate and receives an annual average of 100 mm rainfall, but rainfall is extremely variable among years (Gross
et al. 1995). The area contains rocky, undulating terrains,
and small rock strewn hills with bare ground except for some
xerophytic plants in valleys, wadis, and dry river bottoms.
There are 3 major types of habitat where we conducted
our study. These are cliff face, plateau, and the grave area
habitats. We briefly describe each as follows. The cliff face
is an open, steep-sloped terrain habitat frequently utilized
by ibex. The cliff face provides good escape and refuge for
Nubian ibex, but little forage (Tadesse and Kotler 2010).
The plateau is an open habitat on the top of the cliff with
scattered vegetation. Nubian ibex regularly use this habitat;
however, the level of habitat use by Nubian ibex may vary
depending on the intensity of tourist activity and other
human impacts. The “grave area” habitat (here after the
“garden” habitat) is an area with tended, watered gardens
and lawns where habitat productivity and food and moisture
availability is much greater than for either the cliff face or the
plateau habitats, but it also has the highest use by humans.
The ibex especially use the garden habitat from June to
December when food resources are scarce in other habitats
(Tadesse and Kotler 2010). The garden habitat is an aesthetic
and recreational site that is visited by many tourists especially
on weekends. Nubian ibex are the leading wildlife attraction
to tourists in our study site. The tourists visiting our study site
usually arrive on private vehicles or tour buses and so may
have substantial impact on the patch use behavior of ibex.
When we examined number of tourists in the park area and
hiking along the plateau on weekends versus weekdays, we
found that there were substantially more tourists present
on weekends (727.38 on weekends vs. 381.00 on weekdays,
t = 8.223, n = 16, P < 0.001).
Field experiments
We measured the GUDs of Nubian Ibex under the impact
of tourism. Lower GUDs signify lower costs of foraging and
greater foraging efficiency. In this manner, GUDs provide
quantitative measures of foraging costs and foraging efficiencies and can reveal habitat preferences and assessments at
small spatial and temporal scales. To test the temporal and
spatial impact of tourists, we measured GUDs of Nubian ibex
in different habitat types under the influence of tourists in
2 separate field experiments. We conducted the first field
experiment for 4 consecutive weeks in October 2007, and
the second for 16 consecutive days in November 2007. We
describe the details of each field experiment as follows.
Measurement of GUDs in different habitat types on weekdays
versus weekends
Once Nubian ibex became accustomed to experimental feeding trays and fed regularly from them, we chose one site in
each of the 3 habitat types in which to measure GUDs. The
habitats sampled were: cliff face, plateau, and garden habitats.
We set out a single permanent line in each habitat type
along which we placed 4 feeding trays spaced 20-m apart. The
wooden feeding trays measured 46 × 30 × 12 cm and included
a 6-cm wire mesh fence covering. Into each tray, we placed
100 g of compressed food pellets thoroughly mixed with
1.3 kg of nonedible 3-cm-long pieces of plastic irrigation tubing. The presence of the substrate increases search time for
the ibex while feeding from the trays and causes diminishing
returns in which harvest rates decline as food is depleted from
the patch (Hochman and Kotler 2006a). Covering the trays
with the open mesh fencing prevented ibex from pushing the
nonedible substrate out of the wooden trays. It also better
1259
Tadesse and Kotler • Impact of tourism on Nubian Ibex (Capra nubiana)
mimicked natural foraging by forcing ibex to insert their
muzzles between the links of the wire fence mesh as much
as they do when browsing leaves from inside the branches of
natural shrubs (Hochman and Kotler 2006a).
For each foraging bout, the feeding trays provisioned with
food were left for 24 h in the field to allow Nubian ibex to
discover and feed from them. To verify that only Nubian ibex
removed food from the trays, we spread sand around each
tray, and identified the tracks left on sand during each foraging bout. When the tracks of other animal species were seen
on the sand spread around the experimental tray, the GUD
data were not collected and included in the analyses. Then,
we sieved and collected the remaining food pellets from each
tray and later in the laboratory weighed them on an electronic balance to determine the GUDs. We then replenished
each tray with another 100 g of food pellets.
To assess the impacts of tourists on the patch use behavior of ibex in different habitat types, we collected GUD data
on days of the week that differ in the level of tourist activity:
2 days in the middle of the week (Tuesday, Wednesday; low
tourist activity) and 2 days on the weekend (Friday, Saturday;
high tourist activity). This allowed us to compare the impact
of tourists on the GUDs of Nubian ibex in different habitat
types (i.e., plateau, cliff face, and garden habitat) during the
weekday versus weekend.
We used ANOVA (Systat version 10) to analyze the impact
of tourists on the GUDs of Nubian ibex, with time (weekday
vs. weekend), habitat type (plateau vs. cliff face vs. garden
habitat), and the interactions of time and habitat type as
factors.
Impact of tourist presence and spatial position on GUDs and
vigilance
This field experiment examined the extent of tourist impact
on the patch use behavior of Nubian ibex in the cliff habitat
based on the location of the tourist along the slope relative to
the ibex. The experiment was conducted by selecting a steep
slope cliff face habitat where tourists could disturb the ibex
from different places along the slope. Accordingly, we set 9
feeding trays arrayed 3 × 3 with 10 m between trays. We provided the appropriate tourist disturbance by walking on the
up slope, alongside, or down slope from the feeding tray grid
at a distance of 25 m from the closest feeding stations for 3
consecutive hours during which time the ibex could exploit
the trays. When the control treatment level was called for, we
were not present near trays. We ran 4 rounds of the complete
experimental protocol of control, down slope, alongside, or
up slope from trays. We rotated the order of treatment levels
between rounds according to a Latin square.
Simultaneously with provisioning feeding trays and collecting GUDs, we counted the number of Nubian ibex observed
in the vicinity of the experimental feeding station and
recorded their sex and age class. After the group scan method
proposed by Altmann (1974) and Martin and Bateson (1993),
we also conducted focal animal observations of target individuals near the experimental feeding station to quantify the
time devoted to the activities of vigilance, feeding, walking,
resting, or other activities. Because vigilance is expected to be
the strongest indicator of human disturbance (Third World
Conference on Mountain Ungulates 2002), it is the dependent variable of greatest interest. Moreover, the influence of
group size on the vigilance level of Nubian ibex was taken
into account because group size often affects vigilance activity
in ungulates (e.g., Roberts 1996; Manor and Saltz 2003).
We took ibex individuals representing each sex and age
class for focal observations each day, randomly selecting an
individual from each sex and age class from the group of
ibex coming to feed from the experimental feeding trays. For
each focal observation, we noted the type of activity in which
the focal individual was engaged at the start of the observation period and recorded the length of time spent in different activities mentioned above. Observation periods lasted
for 10 min for each focal individual. A total 32 ibex (i.e., 12
adult females, 9 subadults, and 11 juveniles) totaling 5.2 h
were taken for the focal observations. In no instance did
adult male ibex feed from the feeding trays and so were not
included in the analysis.
We analyzed the effect of tourist presence and tourist
spatial position on the cliff face (up slope vs. alongside vs.
down slope vs. control) on the GUDs of Nubian ibex using
Anova and a post hoc Tukey’s HSD test for multiple comparisons. We analyzed focal animal observations using multivariate analyses of variance (MANOVA) and univariate tests to
quantify the effect of the spatial position of tourist on the
vector of the proportion of times spent in different activities, including the proportion of time spent vigilant (arcsine
transformed).
RESULTS
Measurement of GUDs in different habitat types
on weekday versus weekend
Tourist activity and habitat type significantly affected patch use
in ibex. In particular, ibex showed significantly higher GUDs
on weekends (mean square [MS] = 3071.11; F(2, 91) = 41.59;
P < 0.001; Figure 1) and in the garden habitat (MS = 503.41;
F(2, 91) = 6.82; P < 0.001; Figure 1). Higher GUDs on weekends
than weekdays indicate that greater tourist activity is associated
with higher foraging costs (Figure 1). Also, higher GUDs in
the garden habitat, an area of heavy tourist activity, suggest that
habitat quality may be affected by tourist activity (Figure 1).
The interaction between time (weekday or weekend) and
location (habitat type) was significant, with GUDs for plateau
Figure 1 The effect of habitat type, time period (weekday and weekend),
and the interaction of habitat type and time period on the
giving-up-densities (g pellets) of Nubian Ibex. The error bars
represent +1 SE.
1260
Figure 2 The effect of the spatial position of tourist on the giving-up-densities
(g pellets) of Nubian Ibex in the cliff face habitat. The error bars
represent +1 SE.
and garden habitat types being higher on weekends than on
weekdays (MS = 1037.54; F(2, 91) = 14.05; P < 0.001; Figure 1).
Impact of tourist presence and spatial position on GUDs
Spatial position of tourists significantly affected the GUDs
of feeding ibex on the cliff face habitat (MS = 2273.43;
F(3, 140) = 34.02; P < 0.001; Figure 2). Highest GUDs occurred
when the tourist walked up slope from feeding trays, followed
by alongside, and then down slope (Figure 2). Moreover,
all instances of tourist presence significantly raised GUDs
compared with that of the control (absence of tourist;
Figure 2). A post hoc Tukey’s HSD test showed a significant
difference in GUDs between up slope versus alongside, and
up slope versus down slope (Figure 2), but not alongside
versus down slope (Figure 2).
Focal animal observations
Spatial position of the tourists on the cliff significantly
affected ibex behavior around the feeding tray stations,
increasing rates of vigilance and decreasing feeding
(MS = 3784.95; F(2, 29) = 24.69; P < 0.001). Highest rates of
vigilance occurred when the tourists disturbed ibex from up
slope (Figure 3). The age class of the focal animal (adult
Figure 3 The effect of the spatial position of tourist on the vigilance level of
Nubian Ibex around the foraging bout. The error bars represent +1 SE.
Behavioral Ecology
Figure 4 The effect of age class on the vigilance of Nibian Ibex around the
foraging bout. The error bars represent +1 SE. The number of focal
individuals considered for this analysis was 12 adult females,
9 sub-adults, and 11 juveniles.
female vs. subadult vs. juvenile) also marginally affected rates
of vigilance (MS = 533.79; F(2, 29) = 3.48; P = 0.05). In particular, adult females showed the highest rates of vigilance,
followed by juveniles, and then subadults (Figure 4). These
results show that tourists have the greatest impact on ibex
when they are allowed to travel in areas up slope from the
ibex. The result further revealed that group size had no significant effect (df = 1; r2 = 0.1061; P = 0.241) on the vigilance
level of ibex.
DISCUSSION
Our results support the efficacy of using behavioral indicators to provide information useful to conservation mangers.
Human disturbance due to tourism affected the foraging
behavior of Nubian ibex. The impact of tourism varied with
the spatial and temporal frames, and this was clearly demonstrated by the GUDs obtained from our field experiments.
Nubian ibex left the feeding trays with highest GUDs in the
garden habitat, a location which many tourists visit especially
on weekends, followed by the plateau, and the cliff face habitats, respectively (Figure 1). This suggests that the cliff face
habitat is safest for ibex due to easy escape from predators
(Kotler et al. 1994; Hochman and Kotler 2006a), impacts of
tourism, and other human disturbances (Muller et al. 1995;
Tadesse and Kotler 2010).
Tourist impacts further caused habitat quality for ibex to
change from day to day. The number of tourists visiting our
study area varies with day of the week, and is almost always
higher on weekends. GUDs should be higher on weekends.
This was true, but on a habitat specific basis (Figure 1).
Ibex left both the plateau and the garden habitats with significantly higher GUDs during the weekend than during the
weekday. This suggests that in these 2 habitats, the impact of
tourism during the weekend is stronger compared with the
cliff face habitat, where GUDs changed little from weekday
to weekend. In fact, GUDs in all 3 habitats were similar on
weekdays (Figure 1), suggesting that habitat selection by ibex
is strongly driven by tourist impacts in our study site. Other
studies also support our findings. For example, Galicia and
Baldassarre (1997) measured the impacts of tourism by comparing the activity time budgets between flocks of flamingos
(Phoenicopterus ruber ruber) disturbed or undisturbed by tour
boats. Their result showed that tour boat disturbance reduced
the feeding time from 40% before disturbance to 24% after, a
40% loss in total feeding time. In addition, boat disturbance
1261
Tadesse and Kotler • Impact of tourism on Nubian Ibex (Capra nubiana)
increased alert behavior of flamingos by 400%. Burger and
Gochfeld (1998) also found that many species of water-birds
decreased their foraging time and increased their vigilance
when people were nearby. Done White et al. (1999) quantified the effect of disturbances on Grizzly Bears (Ursus arctos
horribilis) by alpinists in Montana, USA: this leisure activity led
to a 53% reduction in feeding time by bears, a 52% increase
in movements, and a 23% increase in aggressive behaviors.
The presence of tourists in our study always caused ibex to
increase their GUDs in resource patches regardless of the
tourist’s position relative to the Ibex (Figure 2). Spatial position
of the tourists on the cliff relative to the Ibex also affected
foraging costs for ibex. As predicted, the response was especially
sharp when the tourists were up slope from the ibex. Because
an ibex’s major advantage on a slope is its ability to climb, this
result suggests that a threat positioned above that cuts off this
line of escape negates much of the advantage of being on a cliff
slope, thus making the threat much more serious. Moreover,
predator lethality may increase when the predator approaches
the prey above because the predator can attack down hill, and
it is hard for the prey to easily escape from an actively chasing
predator. This may have consequences for other behaviors.
Brown (1999) showed theoretically that increased predator
lethality will result in an increase in the vigilance rate, GUDs,
and predation risk to the prey individuals. The result of our
focal animal observations obtained during the foraging bouts
supports this. Ibex were most vigilant when tourists were up
slope from them. That the presence of tourists negatively affects
Ibex even in the safe cliff face habitat reveals much about how
severely even animals that appear well habituated to humans
can be affected by tourists.
Many field studies on habitat selection demonstrated that
animals increase their vigilance to reduce risk of predation
(e.g., Kotler et al. 1994; Kohlmann et al. 1996; Hochman and
Kotler 2006b) and human disturbances (Fernández-Juricic
and Tellería 2000; Manor and Saltz 2003), including impacts
of tourism (Muller et al. 1995). In response to such disturbances, foragers may allocate much more time to safety
related activities at the expense of other important activities such as feeding and resting, as do the ibex in this study.
Belanger and Bedard (1990) also noted that human activities resulting in flight and greater alertness increased energy
expenditure by Snow Geese (Chen caerulescens) and reduced
their energy intake due to lower feeding rates.
Regarding the many eyes effect of group size, vigilance level
of individuals is expected to decrease when there are more individuals in the group while at the same time overall vigilance for
the group increases (e.g., Lagory 1986; Elgar 1989; Lima and
Dill 1990; Roberts 1996; Brown 1999; Manor and Saltz 2003).
However, this did not occur here with the ibex. Hochman and
Kotler (2006b) also obtained a similar result for this same ibex
population. These results suggest that for ibex personal information is valued more highly than social information (e.g., Lima
et al. 1985), resulting in vigilance independent of group size (Dall
and Valone 2005). Other possible reasons for a lack of group
size effect include minimal risk of predation, large groups being
attacked disproportionately more often (Brown 1999), or the
sparse vegetation and steep terrain reducing the dilution effect.
Lack of a group size effect on vigilance has been documented
in other species of social ungulates including elk (Cervus elaphus)
and bison (Bison bison) (Laundre et al. 2001; Beauchamp 2003).
This study demonstrates the utility of behavioral indicators.
This method requires relatively little researcher input to determine how habitat quality varies from day to day and between
habitats in relation to human activity. The resulting information is valuable to conservation managers deciding when and
where to allow access by tourists and by how many people. Our
results also suggest that considerable attention should be given
to limit human access to provide some foraging localities where
ibex can remain undisturbed. Moreover, using behavioral
indicators allowed us to track changes in cost from day to day
rather than on the longer time scale that demographic methods would require. Furthermore, we were also able to assess
how the presence of humans up slope or down slope from foraging ibex affects foraging costs and time budgets. This information is valuable for planning hiking trails that have reduced
impact on foraging ibex. It is hard to see how similar information could be gathered using traditional conservation methods
such as measuring demographic parameters or assessing movement using telemetry. Rather than having little to offer conservation and management, behavioral ecologists have valuable
concepts and tools that can obtain just the information most
needed by conservation managers and do so quickly, cheaply,
and accurately.
We thank Marc Goldberg for his technical help. We are grateful
to Keren Embar, Cecilia Iribarren, Noa Angel, Ishai Hoffman, and
Oded Berger for their assistance in the field work, and especially we
thank Yaron Ziv, and Ofer Ovadia for their valuable comments during different stages of this work. We also thank the editor-in- chief,
Ben Hatchwell, and the 2 anonymous reviewers whose comments
helped much to improve the manuscript. We forward our heartfelt
thanks to the staff of En Avdat National Park in particular and Israeli
Nature Reserves and National Parks Protection Authority in general
for their cooperation in permitting us to work on the endangered
Nubian Ibex and their habitats. The research was conducted at the
Marco and Louise Mitrani Department of Desert Ecology, Blaustein
Institutes for Desert Research, Ben-Gurion University of the Negev.
During this research, State of Israel provided financial assistance.
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