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Prey species may adjust their use of antipredator behaviours to counter the hunting strategies (e.g. ambush versus cursorial) and the level of risk imposed by different predators. Studies of suites of behaviours across well-defined contrasts of predation risk and type are rare, however. Here we explored the degree to which six herbivore species adjusted their antipredator behaviours to two predator treatments (lion, Panthera leo, versus cheetah, Acinonyx jubatus, and wild dogs, Lycaon pictus). We focused on prey behaviour (vigilance, grouping, temporal use) at waterholes. We predicted that if the hunting strategy of the predator was the key driver of antipredator behaviour, ambushing lions would elicit a greater response than cursorial cheetah and wild dogs. Alternatively, if predator preference was the main driver, then we expected prey species to adjust their antipredator behaviours in response to the predators that specifically target them (i.e. preferred prey of the different predators). Overall, we found that the herbivores maintained greater vigilance, generally moved in larger groups and used waterholes less at dawn, at dusk or at night (when lions are active) when exposed to the potential threat of ambushing lions. However, some species within the accessible prey range of cheetah and/or wild dogs (i.e. red hartebeest, warthog, gemsbok) moved in larger groups when exposed to these predators. Yet, the magnitude of the differences in group size for these herbivores were small. Thus, we suggest that, overall, the potential threat of ambushing lions was the main driver of antipredator behaviour around waterholes, probably determined by prey weight preference and the possibility of being ambushed.
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Herbivores employ a suite of antipredator behaviours to minimize risk
from ambush and cursorial predators
Douglas F. Makin
a
,
*
, Simon Chamaill
e-Jammes
b
, Adrian M. Shrader
a
a
School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
b
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Universit
e de Montpellier, Universit
e Paul-Val
ery MontpelliereEPHE, Montpellier, France
article info
Article history:
Received 7 November 2016
Initial acceptance 11 January 2017
Final acceptance 2 March 2017
MS. number: 16-00973R
Keywords:
group size
hunting strategies
predatoreprey interactions
prey preferences
temporal activity
vigilance
Prey species may adjust their use of antipredator behaviours to counter the hunting strategies (e.g.
ambush versus cursorial) and the level of risk imposed by different predators. Studies of suites of be-
haviours across well-dened contrasts of predation risk and type are rare, however. Here we explored
the degree to which six herbivore species adjusted their antipredator behaviours to two predator
treatments (lion, Panthera leo, versus cheetah, Acinonyx jubatus, and wild dogs, Lycaon pictus). We
focused on prey behaviour (vigilance, grouping, temporal use) at waterholes. We predicted that if the
hunting strategy of the predator was the key driver of antipredator behaviour, ambushing lions would
elicit a greater response than cursorial cheetah and wild dogs. Alternatively, if predator preference was
the main driver, then we expected prey species to adjust their antipredator behaviours in response to the
predators that specically target them (i.e. preferred prey of the different predators). Overall, we found
that the herbivores maintained greater vigilance, generally moved in larger groups and used waterholes
less at dawn, at dusk or at night (when lions are active) when exposed to the potential threat of
ambushing lions. However, some species within the accessible prey range of cheetah and/or wild dogs
(i.e. red hartebeest, warthog, gemsbok) moved in larger groups when exposed to these predators. Yet, the
magnitude of the differences in group size for these herbivores were small. Thus, we suggest that, overall,
the potential threat of ambushing lions was the main driver of antipredator behaviour around water-
holes, probably determined by prey weight preference and the possibility of being ambushed.
©2017 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Prey possess a whole suite of behaviours that they may employ
to reduce predation risk (Caro, 2005; Lima &Dill, 1990). In partic-
ular, vigilance and grouping are exible behaviours that can be
used to reduce risk, although they come with associated costs. For
example, increased vigilance allows individuals to detect attacks
earlier, providing a greater chance of escaping (Lima &Bednekoff,
1999), but often reduces food intake rate (Fortin, Boyce, Merrill, &
Fryxell, 2004). Living in larger groups allows individuals to poten-
tially benet from dilution, collective vigilance and/or deterrence
effects (Beauchamp, 2003; Schmitt, Stears, Wilmers, &Shrader,
2014), but could increase intragroup competition (Krause &
Ruxton, 2002). Because of these costs, prey are not expected to
always display a full suite of antipredator behaviours, but rather to
nely adjust antipredator behaviours to the level of risk, by prior-
itizing certain behaviours over others (e.g. vigilance, grouping,
temporal shifts; Creel, Schuette, &Christianson, 2014).
Predation risk varies both temporally and spatially across the
landscape. This translates into a landscape of fear(Laundr
e,
Hern
andez, &Altendorf, 2001) that is shaped by differences in
the prey's perception of the likelihood of meeting a specic pred-
ator (e.g. predator density, similar landscape use between predator
and prey, shared time of activity), and of the likelihood of being
killed when attacked (i.e. threatof the predator). However, as not
all predators are the same, prey species probably adjust the extent
to which they utilize different antipredator behaviours (e.g. vigi-
lance levels, group size) in response to different predators or
predator combinations.
One factor that probably greatly inuences antipredator stra-
tegies is the hunting strategy of a predator. For instance, large
mammalian predators are usually classied as either cursorial or
stalking/ambush predators. Cursorial predators roam over large
areas looking for prey, and then approach prey rapidly and silently
when found (Creel &Creel, 2002; Pomilia, McNutt, &Jordan, 2015).
As a result, their distribution in the landscape is generally unpre-
dictable, and thus prey tend not to associate specic places with
predation risk from these species (see discussion in Preisser,
Orrock, &Schmitz, 2007). In contrast, ambush predators rely on
*Correspondence: D. F. Makin, School of Life Sciences, University of KwaZulu-
Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa.
E-mail address: doug.makin4@gmail.com (D. F. Makin).
Contents lists available at ScienceDirect
Animal Behaviour
journal homepage: www.elsevier.com/locate/anbehav
http://dx.doi.org/10.1016/j.anbehav.2017.03.024
0003-3472/©2017 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Animal Behaviour 127 (2017) 225e231
places where the likelihood of meeting prey is high, relying on
small-scale vegetation cover, rather than speed, to approach prey
(Preisser et al., 2007). Thus, areas attracting prey usually also attract
ambush predators, and thus prey should increase their antipredator
behaviour when using these areas (Valeix, Fritz, et al., 2009). For
example, within the arid and semiarid environments that we
studied here, water sources attract both large mammalian herbi-
vores and their ambush predators such as lions, Panthera leo (Ogutu
et al., 2014; Thaker et al., 2011; Valeix et al., 2010; de Boer et al.,
2010).
In addition to a predator's hunting strategy, prey species prob-
ably also consider the degree of threat posed by a specic predator.
Predators tend to target prey species within specic body size
ranges (for lion: Clements, Tambling, Hayward, &Kerley, 2014;
Hayward, 2006; Hayward, Hayward, Tambling, &Kerley, 2011).
Thus, some predators will be more of a threat than others. For
example, lions are more likely to attack a 290e340 kg zebra, Equus
quagga, than a 40e70 kg impala, Aepyceros melampus (Hayward &
Kerley, 2005). As a result, prey species should increase the extent
to which they utilize specic behaviours (e.g. increase vigilance
levels) in response to their primary predators, compared to more
peripheral predators. Yet, an overarching factor that greatly in-
uences predation risk is the overlap in the activity patterns of
predators and prey (i.e. whether they are nocturnal or diurnal;
Kronfeld-Schor &Dayan, 2003). To minimize contact with preda-
tors, prey species can shift their temporal use of the landscape to
periods when predators are least active. For example, in Hwange
National Park, Zimbabwe, most ungulate species appear to avoid
coming to drink at night when lions are in the vicinity of the
waterholes (Valeix, Fritz, et al., 2009).
Here we explored the degree to which prey species adjust their
antipredator strategies in response to different predators. We
focused our observations at waterholes in a semiarid ecosystem as
a model of key interaction areas between predators and prey, and
studied the antipredator behaviour (grouping, vigilance, time of
use) of six large herbivore species (i.e. eland, Taurotragus oryx;
gemsbok, Oryx gazella; plains zebra, red hartebeest, Alcelaphus
buselaphus caama; warthog, Phacochoerus africanus; blue wilde-
beest, Connochaetes taurinus) at these waterholes. We did this in
two sections of the same reserve that were separated by fences, one
with only lions (ambush predators), the other with cheetah, Aci-
nonyx jubatus, and wild dogs, Lycaon pictus (both cursorial preda-
tors) and no lions.
In many ecosystems, lions select and kill in areas close to water
(Ogutu et al., 2014; Thaker et al., 2011; Valeix et al., 2010; de Boer
et al., 2010). Cheetah and wild dog may also do this, but their
presence near waterholes might be less predictable as their
cursorial hunting strategies probably increase their use of areas
away from water sources, more so than lions (e.g. Ndaimani,
Tagwireyi, Sebele, &Madzikanda, 2016). Thus, we predicted that
if hunting strategy was a key driver of prey a ntipredator behaviour,
lions would elicit a greater antipredator response from prey spe-
cies than the less spatially predictable cheetah and wild dogs. This
could be through all the prey species changing their antipredator
behaviours (e.g. increased vigilance and larger groups) and/or
adjusting their temporal activity patterns more in response to li-
ons than to cheetah and wild dogs. Alternatively, if antipredator
behaviours of prey species are driven more by prey preferences of
predators, then we would expect individual prey species to change
their antipredator behaviours more in response to the predators
that specically target them (i.e. prey falling within the predator's
preferred prey weight range) than if the prey species falls outside
the predator's prey weight range. This could then result in species-
specic differences both within and between the predator
sections.
METHODS
Ethical Note
The University of KwaZulu-Natal approved all aspects of the
research design (Ethics code: 058/14/Animal).
Data Collection
We conducted our study in Tswalu Kalahari Reserve (Tswalu
hereafter) in the Northern Cape, South Africa (S 27
13
0
30
00
and E
022
28
0
40
00
) from October 2013 to April 2015. The fenced reserve
encompasses 1000 km
2
of restored farmland (Cromhout, 2007)
located in the southern Kalahari (Roxburgh, 2008). Tswalu has a
mean annual rainfall of 250 mm, with an extended dry season
lasting from May to September/October when there is less than
10 mm rainfall (Roxburgh, 2008). Large mammalian herbivores
found in the reserve include kudu, Tragelaphus strepsiceros,
springbok, Antidorcas marsupialis, gemsbok, eland, sable, Hippo-
tragus niger, zebra, red hartebeest, warthog and wildebeest.
Tswalu is divided into two adjacent sections which support
different large predator populations, but are separated by about
50 m comprising a road and two predator fences. The western
section of the reserve (200 km
2
) contains lion (N¼24), while the
eastern section (800 km
2
) contains populations of cheetah (N~10)
and wild dog (N¼14). Habitat types across both sections are
similar, made up of Digitaria polyphylla-dominated hills, Stipagrostis
uniplumis-dominated plains and valleys and Anthephora pubescens-
dominated sand dunes (see Van Rooyan, 1999). Likewise, both
sections have a similar mean annual rainfall (mm), with
326 ±40 mm falling within the western section compared to
345 ±42 mm within the eastern section recorded over a 9-year
period. We limited data collection to the herbivore species that
occurred in both sections of the reserve. These included eland,
gemsbok, zebra, red hartebeest, warthog and wildebeest. The her-
bivores living in the two sections face different levels of predation
risk due to the hunting strategy employed, their activity patterns
and the prey weight preferences of the different predator species
(Hayward &Slotow, 2009; Hayward et al., 2007). Lion are stalk and
ambush predators that are predominantly active at night, while
cheetah and wild dogs are mostly diurnal and hunt by chasing
down their prey (Hayward &Somers, 2009). Comparing prey
weight preferences from a multisite analysis, Clements et al. (2014)
determined that lion have an accessible prey weight class range of
32e632 kg and therefore all six herbivores species monitored in
our study fall within their prey weight range. However, they tend to
prefer prey weights of 92e632 kg (Clements et al., 2014) with
wildebeest and zebra often preferentially targeted over other prey
(Sinclair, Mduma, &Brashares, 2003). In contrast, cheetah and wild
dogs have smaller accessible prey weight ranges of 14e135 kg (with
a peak weight mode of 36 kg; Hayward, Hofmeyr, O'Brien, &Kerley,
2006) and 10e289 kg (peak weight modes of 16e32 kg and
120e40 kg; Hayward, Hofmeyr, et al., 2006), respectively. There-
fore, only warthog and red hartebeest fall within the accessible
range of cheetah, while all the herbivores, except eland, fall within
the accessible prey range of wild dogs (Clements et al., 2014).
However, although warthog fall within the accessible prey range of
both cheetah and wild dogs, they are generally avoided (Clements
et al., 2014;Hayward, Hofmeyr, et al., 2006). Despite discrep-
ancies in prey weight range preferences, cheetah and wild dogs
have the highest recorded dietary overlap (73.5%; Hayward &
Kerley, 2008) of the large African predator guild and therefore
present a signicant cumulative predation risk to shared prey
species. Within Tswalu, lion prey upon wildebeest and gemsbok
(Roxburgh, 2008), while cheetah prey on red hartebeest and
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231226
springbok, and wild dogs prey on kudu, red hartebeest and impala
(Makin, n.d).
Throughout the study, all three predators were observed uti-
lizing waterholes. Moreover, lions were active at waterholes pre-
dominantly at night and during crepuscular periods (80% of
observations). In contrast, cheetah and wild dogs were more
diurnal, visiting waterholes during the crepuscular periods and
during the day (65% and 70% of observations, respectively).
To assess the antipredator strategies used by the different prey
species in response to the different predators, we deployed Bush-
nell video camera traps with heat-motion sensors at ve water-
holes in the cheetah and wild dog section and three waterholes in
the lion section. Camera traps were attached to trees 1 m above the
ground. This ensured that each camera's eld of view extended
from the ground up to over 2.5 m. Camera traps were placed so that
they had a clear view of the entire waterhole. This enabled all in-
dividuals visiting the waterholes to be recorded. Only videos
showing clearly discernible individuals were included in the data
analysis.
We limited the chances of collecting data from the same indi-
vidual multiple times within a single recording event, by rst
noting when individuals left the eld of view. We then waited
30 min before collecting data from groups of the same species
comprising the same number of individuals (i.e. potentially the
same group) that entered the eld of view (Linkie &Ridout, 2011;
Tambling et al., 2015). Previous studies have suggested that
30 min represents a sufcient trade-off between recording the
same individual multiple times and missing new individuals
(Rovero, Jones, &Sanderson, 2005; Tambling et al., 2015).
We analysed the video camera data recording for (1) herbi-
vores species, (2) time of day (day: 0600e1700; crepuscular:
0400e0600 and 1700e1900; night: 1900e0400), (3) typical group
size (i.e. the reection of the animal's rather than the human
observer's experience within the group; calculated as G¼(PNi
2
)/
(N), where the sum of the squares of all individuals in all groups
(Ni
2
) is divided by the total number of individuals seen (N);
Jarman, 1974; Reiczigel, Lang, R
ozsa, &T
othm
er
esz, 2008), (4)
predator section (lion versus cheetah and wild dogs), and (5)
proportion of time individual herbivores within groups were
vigilant at waterholes. We followed the approach of P
eriquet et al.
(2010) where vigilance was monitored for a focal animal within
the centre of each group. We did this as central individuals are
less likely to be killed than individuals on the periphery; thus, any
increase in vigilance by central individuals is likely to reect an
increase in vigilance for all individuals within the group. We
considered an animal to be vigilant when it stood in an upright
position, head alert and actively scanning with ears held forward.
All individuals recorded were adult members of the group. As
females with juveniles will maintain higher levels of vigilance to
protect dependent offspring we focused on the vigilant responses
of females without juveniles (P
eriquet et al., 2010). Additionally,
the study was conducted following a severe drought year and
therefore there was little recruitment into the different herbivore
populations during this period, with most breeding groups con-
sisting of only adults and subadults from the previous year (Makin
Pers. Obs.).
We recorded the proportion of time each individual spent
vigilant at waterholes over a 10 min period or over the entire time
herbivore groups were drinking at a waterhole if it was less than
10 min. We dened both these time periods as an observation.
Vigilance was recorded for individuals within groups that were
close to the waterhole (i.e. drinking or standing on the water's
edge). Within the lion section, we recorded 85 wildebeest, 23
eland, 91 gemsbok, 147 zebra, 36 red hartebeest and 88 warthog
observations, while in the cheetah and wild dog section we
recorded 182 wildebeest, 76 eland, 222 gemsbok, 78 zebra, 187 red
hartebeest and 275 warthog observations.
Statistical Analysis
For each herbivore species, we compared the effect of predator
section (i.e. lion versus cheetah and wild dog) and the interaction
between predator section and herbivore species on changes in the
antipredator behaviours of typical group size and proportion of
time spent vigilant using generalized linear models (GLM) with
Poisson and binomial errors, respectively. To keep the model sim-
ple, we did not include group size as a predictor of the proportion of
time spent vigilant. Preliminary analyses showed that there was no
relationship for ve of the six species (all P>0.10), with only red
hartebeest showing a slight positive relationship between indi-
vidual vigilance and increasing group size (z¼3.86, P<0.01), but
this was of a very small magnitude (lion section: y¼0.03xþ0.33;
cheetah and wild dog section: y¼0.03xþ0.11). For each herbivore
species in each predator section, we visually displayed the diel
distribution of visits to waterholes using kernel-based density
plots. In addition, we tested for the statistical signicance of dif-
ferences between predator sections by tting a GLM with Poisson-
distributed errors with the number of herbivore observations
recorded at a waterhole within each time period (night, crepus-
cular, day) as the response variable, and time period and predator
section as explanatory variables, including interactions between
variables. Warthog were not recorded visiting waterholes at night
in the lion section and therefore could not be compared for this
period. All analysis was performed using R 3.21 (R Core Team, 2014)
using the lme4 package (Bates, Maechler, &Bolker, 2012), MASS
package (Venables &Ripley, 2002) and the multcomp package
(Hothorn, Bretz, &Westfall, 2008).
RESULTS
Typical group sizes varied signicantly between herbivore
species (x
2
10
¼732.7, P<0.01), between the predator sections
(x
2
6
¼51.5, P<0.01) and for the interaction between herbivore
species and the different predator sections (x
2
5
¼51.4, P<0.01).
Overall, group size did not differ between the sections for eland
(z¼1.7 2 , P¼0.08; Fig. 1a). Zebra (z¼2.12, P¼0.03) and wilde-
beest (z¼5.05, P<0.01) maintained larger groups in response to
lion than to cheetah and wild dogs. In contrast, gemsbok (z¼2.18,
P¼0.03), red hartebeest (z¼2.37, P¼0.018) and warthog
(z¼3.45, P<0.01) maintained slightly larger groups in response
to cheetah and wild dogs than in response to lion (Fig. 1a).
All the herbivore species tended to be more vigilant at water-
holes within the lion section compared to within the cheetah and
wild dog section (Fig. 1b). Differences, however, were only statis-
tically signicant for gemsbok (z¼2.52, P¼0.01), red hartebeest
(z¼3.54, P<0.01) and warthog (z¼2.88, P<0.01) groups, and not
for eland (z¼1.69, P¼0.09), zebra (z¼1.92, P¼0.06) or wilde-
beest (z¼0.94, P¼0.35; Fig. 1b).
Gemsbok, zebra and wildebeest were predominantly diurnal at
waterholes in both predator sections (Fig. 2). However, when we
compared the differences in temporal waterhole use (day, crepus-
cular, night) for the same species across sections, we found statis-
tically signicant differences in the waterhole use of gemsbok
(z¼2.58, P¼0.01), zebra (z¼2.48, P¼0.02) and wildebeest
(z¼2.14, P¼0.03). Specically, in the lion section, these herbi-
vores visited the waterholes less during the night (z¼10.98,
z¼5.161, z¼3.63, all P<0.01, respectively) and during
crepuscular periods (z¼3.58, z¼3.59, z¼3.35, all P<0.01,
respectively) than they did in the cheetah and wild dog section.
There were no statistically signicant differences in temporal use of
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231 227
waterholes for eland (night: z¼0.12, P¼1.00; crepuscular:
z¼0.12, P¼1.0 0; d a y: z¼0.36, P¼0.998), red hartebeest
(night: z¼0.69, P¼0.982; crepuscular: z¼0.33, P¼0.999; day:
z¼0.29, P¼0.997) and warthog (crepuscular: z¼0.03, P¼1.0 0 ;
day: z¼0.26, P¼0.998; Fig. 2).
DISCUSSION
In response to predators, prey species can adjust their behaviour
in several ways to reduce risk (Caro, 2005; Creel et al., 2014; Lima &
Dill, 1990). However, as not all predators impose the same threat,
the behavioural strategies utilized by prey are likely to vary in
response to different predator hunting modes (i.e. ambush versus
cursorial), overlap in activity patterns (i.e. nocturnal versus diurnal)
and their prey preferences. We found that the antipredator
behavioural strategies of six herbivore species differed between the
lion and cheetah and wild dog sections. Overall, lions had the
greatest effect suggesting that the threat of this ambush predator
around waterholes was a key driver of the observed antipredator
behavioural adjustments of most of the herbivores.
It is possible, however, that the differences in antipredator be-
haviours we recorded were driven by landscape differences be-
tween the sections, although the two sections were only separated
by about 50 m, had identical history of land use, similar climates/
rainfall and similar topography (Cromhout, 2007; Van Rooyan,
1999). As a result, we believe that it is more likely that the
behavioural differences between the two sections were driven by
differences in predation risk posed by the two sets of predators.
Across African landscapes, lions are one of the most dangerous
predators that herbivores can encounter. The combination of their
large body size and group-hunting tactics mean that they can
successfully kill a number of species ranging from warthogs to large
herbivores including buffalo, Syncerus caffer (550e700 kg), giraffe,
Giraffa spp. (700e1400 kg) and in some cases even elephants,
Loxodonta africana (up to 7 years old; 700e900 kg; Hanks, 1972;
Loveridge, Hunt, Murindagomo, &Macdonald, 2006). Moreover,
lion actively select habitats close to waterholes and therefore pre-
sent a signicant risk to herbivores aggregated around these water
sources (Valeix, Fritz, et al., 2009; de Boer et al., 2010).
Comparing differences in the herbivore species' antipredator
behaviours between predator sections, we found that most
*****
*
*
*
Lion Cheetah/wild dogs
25
20
15
10
5
0
Typical group sizes
0.6
0.5
0.4
0.3
0.2
0.1
0
(a)
(b)
Proportion of time spent vigilant
Eland Gemsbok Plains zebra Red hartebeest Warthog Wildebeest
Eland Gemsbok Plains zebra Red hartebeest Wartho
g
Wildebeest
Figure 1. (a) Typical group sizes and (b) mean proportion of time herbivore groups were vigilant at waterholes in the two predator sections (lion versus cheetah and wild dogs).
Bars represent SE. *P<0.05.
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231228
herbivore species adjusted their behaviours so as to minimize the
risk of attack from ambushing lions. This was evident in that all the
herbivore species maintained greater vigilance in the lion section
(signicantly so for gemsbok, red hartebeest and warthog) than the
cheetah and wild dog section. This could also be partly because
vigilance may not be so necessary in the face of cursorial predators
that often testherds for vulnerable animals (Creel &Creel, 2002).
Moreover, all herbivores preferred to utilize waterholes during
midday when lions tended to be less active (Tambling et al., 2015;
Valeix, Loveridge, et al., 2009). The fact that zebra, wildebeest and
gemsbok (all preferred prey of lions) reduced their night-time us-
age of waterholes in the lion section indicates that these species
adjusted their activity patterns to reduce contact with lions. In
addition, both zebra and wildebeest moved in larger groups in the
lion section than in the cheetah and wild dog section. Thus, both
zebra and wildebeest increased the use of their range of anti-
predator behaviours against their main predator, lions. This was
similar to Valeix, Fritz, et al. (2009) and Valeix, Loveridge, et al.
(2009) who found that in Hwange National Park, wildebeest and
zebra increased their group sizes with the long-term risk of
encountering lion around waterholes.
As all the herbivore species in our study fall within the prey
weight range of lions, it is difcult to tease apart which factors are
driving the observed behavioural differences between the herbi-
vores in the two predator sections. However, as the main species
making these adjustments (i.e. zebra and wildebeest) are generally
preferred prey species of lions, we suggest that it is probably the
combination of prey preference of the lions (Sinclair et al., 2003)
and heightened predation risk at the waterholes (i.e. possibility of
being ambushed) that lead to adjustments to these and the other
species' antipredator strategies (de Boer et al., 2010).
In contrast to the general response towards lions, we found that
red hartebeest, warthog (accessible and avoided prey of cheetah and
wild dog, respectively; Hayward, O'Brien, Hofmeyr, &Kerley, 2006;
Marker, Dickman, Wilkinson, Schumann, &Fabiano, 20 07)and
gemsbok (within the prey range of wild dogs; Hayward, Hofmeyr,
et al., 2006) moved in larger groups at waterholes in the cheetah
and wild dog section. This suggests that these herbivores were
responding to the combined threat from cheetah and wild dog. Yet,
all three of these herbivore species also fall within the prey range of
lions. A potential reason for why these herbivores maintained larger
groups in the presence of cheetah and wild dogs is that it is possible
that the combined risk from these predators was greater than the
risk from lions alone. This may have been due to more frequent
contact with cheetah and wild dogs than lions. Within the lion
section, there were only two prides of lions. In contrast, in the
cheetah and wild dog section there were a minimum of 10 cheetahs,
each moving separately (D. F. Makin, personal observation), and one
pack of wild dogs (i.e. 11 potential encounters with predators).
Moreover, as cheetahand wild dogs are predominantly active during
the day (Hayward &Somers, 2009), and thus there is a greater
overlap in the activity patterns of these predators and their prey, it is
possible that by moving in larger groups these herbivores reduced
the combined risk from both predators (Clements et al., 2014).
Despite this, the differences in group size for all six herbivore
species were small with typical group sizes differing by only a few
individuals between the predator sections. This suggests that group
size may in fact not be a major adaptive response to increased
0.25
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Cheetah and wild dogs
Lions
Cheetah and wild dogs
Lions
Cheetah and wild dogs
Lions
Cheetah and wild dogs
Lions
Cheetah and wild dogs
Lions
Cheetah and wild dogs
Lions
0000 0300 0600 0900 1200 1500 1800 2100 2400
0000 0300 0600 0900 1200 1500 1800 2100 2400
0000 0300 0600 0900 1200 1500 1800 2100 2400 0000 0300 0600 0900 1200 1500 1800 2100 2400
0000 0300 0600 0900 1200 1500 1800 2100 2400
0000 0300 0600 0900 1200 1500 1800 2100 2400
Density
0.3
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0
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Time (hours)
(a)
(b)
(c)
(d)
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(f)
Figure 2. Density kernel plots estimating the daily activity patterns of (a) eland, (b) gemsbok, (c) zebra, (d) red hartebeest, (e) warthog and (f) wildebeest at waterholes in the two
predator sections (cheetah and wild dog: dotted black line; lions: solid black line) and time periods (night: dark grey; crepuscular: light grey; day: white).
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231 229
predation risk from predators at waterholes in Tswalu. If this is the
case, then this suggests that all the herbivores in our study adjusted
their antipredator behaviours more in response to the potential
threat from the two prides of ambushing lions than to the cursorial
cheetah and wild dogs. Additional support for this comes from the
nding that herbivores preferred by cheetah and wild dogs did not
shift to utilizing water holes during the night when these predators
were less active (Ford et al., 2015; Hilborn, Pettorelli, Orme, &
Durant, 2012; but see Cozzi et al., 2012). One possible reason for
this is that there may have been costs that prevented these herbi-
vores from doing this, but it is unclear what these costs may be.
In conclusion, we found that the herbivores tended to display
stronger antipredator behaviour in response to lions (i.e. greater
vigilance, larger groups and temporal shift in water hole usage)
than when living with cheetah and wild dogs. This suggests that the
cursorial hunting strategy of cheetah and wild dogs imposed lower
perceived risk around waterholes than the stalk and ambush
strategy adopted by lions. Our study is one of the few that has
directly addressed the effect of hunting mode on prey behaviour,
using a powerful semiexperimental design. Moreover, our results
support the common assertion that ambush predators are likely to
induce stronger nonconsumptive effects on prey than cursorial
predators (Middleton et al., 2013; Preisser et al., 2007).
Yet, as predation risk varies across the landscape (Laundr
e,
Hern
andez, &Ripple, 2010; Shrader, Brown, Kerley, &Kotler, 2008),
behavioural strategies utilized to reduce this risk probably also vary
spatially. As waterholes represent key interaction areas between
predators and prey, the suite of behaviours utilized by each species
we recorded probably reect those best suited against ambush
predators.However, as the possibility of ambush probablydeclines as
herbivores move away from waterholes, herbivores possibly adjust
their antipredator behaviours to reduce the use of behaviours that
decrease risk from ambush predators and increase those that are
better suited against roaming cursorial predators. Observations in
landscapes with multiple predators using contrasting hunting stra-
tegies will be required to test this hypothesis. However, in such a
landscape, Thaker et al. (2011) found that all prey species tended to
avoid the activity areas of ambush, but not of cursorial, predators.
They also found that prey responded more to habitat cues than to
actual predator distribution. See Schmitz (2007) for further discus-
sion on additive or substitutive effects in multipredator systems.
Despite focusing on a number of antipredator behaviours, there
are others we did not consider, for instance multiscale habitat use
(e.g. Padi
e et al., 2015) or reactive responses (e.g. Courbin et al.,
2016). Our study, however, highlights an important point, namely
that ecologists (including ourselves) need to move beyond focusing
on a limited set of behaviours (e.g. just vigilance) when studying
prey species' responses to predation risk. This will be difcult, but is
required, as our results highlight that animals do not reduce risk by
simply adjusting one or two behaviours, but rather exploit and
combine an array of antipredator behaviours.
Acknowledgments
We thank the Oppenheimer family and the Tswalu foundation
for allowing us to conduct the study in Tswalu. Funding for this
research was provided by UKZN, NRF (Research Grant 77582, AMS),
GreenMatter (DM) and the Tswalu Foundation. Two referees pro-
vided constructive comments on the manuscript.
References
Bates, D., Maechler, M., & Bolker, B. (2012). lme4: Linear mixed-effects models using
S4 classes (2011). R package version 0.999375-42 http://CRAN.R-project.org/
package¼lme4.
Beauchamp, G. (2003). Group-size effects on vigilance: A search for mechanisms.
Behavioural Processes, 63(3), 111e121.
Caro, T. (2005). Antipredator defenses in birds and mammals. Chicago, IL: University
of Chicago Press.
Clements, H. S., Tambling, C. J., Hayward, M. W., & Kerley, G. I. (2014). An objective
approach to determining the weight ranges of prey preferred by and accessible
to the ve large African carnivores. PloS One, 9(7), e101054.
Courbin, N., Loveridge, A. J., Macdonald, D. W., Fritz, H., Valeix, M., Makuwe, M. T.,
et al. (2016). Reactive responses of zebras to lion encounters shape their
predator-prey space game at large scale. Oikos, 125, 829e838.
Cozzi, G., Broekhuis, F., McNutt, J. W., Turnbull, L. A., Macdonald, D. W., & Schmid, B.
(2012). Fear of the dark or dinner by moonlight? Reduced temporal partitioning
among Africa's large carnivores. Ecology, 93(12), 2590e2599.
Creel, S., & Creel, N. M. (2002). The African wild dog: Behavior, ecology, and conser-
vation. Princeton, NJ: Princeton University Press.
Creel, S., Schuette, P., & Christianson, D. (2014). Effects of predation risk on group
size, vigilance, and foraging behavior in an African ungulate community.
Behavioral Ecology, 25(4), 773e784.
Cromhout, M. (2007). The ecology of the African buffalo in the eastern Kalahari region,
South Africa [M.Sc. thesis]. Pretoria, South Africa: University of Pretoria.
de Boer, W. F., Vis, M. J., de Knegt, H. J., Rowles, C., Kohi, E. M., van Langevelde, F.,
et al. (2010). Spatial distribution of lion kills determined by the water de-
pendency of prey species. Journal of Mammalogy, 91(5), 1280e1286.
Ford, A. T., Goheen, J. R., Augustine, D. J., Kinnaird, M. F., O'Brien, T. G., Palmer, T. M.,
et al. (2015). Recovery of African wild dogs suppresses prey but does not trigger
a trophic cascade. Ecology, 96(10), 2705e2714.
Fortin, D., Boyce, M. S., Merrill, E. H., & Fryxell, J. M. (2004). Foraging costs of vig-
ilance in large mammalian herbivores. Oikos, 107(1), 172e180.
Hanks, J. (1972). Growth of the African elephant (Loxodonta africana). African Journal
of Ecology, 10(4), 251e272.
Hayward, M. (2006). Prey preferences of the spotted hyaena (Crocuta crocuta) and
degree of dietary overlap with the lion (Panthera leo). Journal of Zoology, 270(4),
606e614.
Hayward, M. W.,Hayward, G. J., Tambling, C. J., & Kerley, G. I. (2011).Do lions Panthera
leo actively select prey or do prey preferences simply reect chance responses
via evolutionary adaptations to optimal foraging? PloS One, 6(9), e23607.
Hayward, M. W., Hofmeyr, M., O'Brien, J., & Kerley, G. I. H. (2006). Prey preferences
of the cheetah (Acinonyx jubatus) (Felidae: Carnivora): Morphological limita-
tions or the need to capture rapidly consumable prey before kleptoparasites
arrive? Journal of Zoology, 270(4), 615e627. http://dx.doi.org/10.1111/j.1469-
7998.2006.00184.x.
Hayward, M. W., & Kerley, G. I. (2005). Prey preferences of the lion (Panthera leo).
Journal of Zoology, 267(03), 309e322.
Hayward, M. W., & Kerley, G. I. (2008). Prey preferences and dietary overlap
amongst Africa's large predators. South African Journal of Wildlife Research,
38(2), 93e108.
Hayward, M. W., Kerley, G. I., Adendorff, J., Moolman, L. C., O'brien, J., Sholto-
Douglas, A., et al. (20 07). The reintroduction of large carnivores to the Eastern
Cape, South Africa: An assessment. Oryx, 41(02), 205e214.
Hayward, M. W., O'Brien, J., Hofmeyr, M., & Kerley, G. I. (2006). Prey preferences of
the African wild dog Lycaon pictus (Canidae: Carnivora): Ecological re-
quirements for conservation. Journal of Mammalogy, 87(6), 1122e113 1.
Hayward, M. W., & Slotow, R. (2009). Temporal partitioning of activity in large
African carnivores: Tests of multiple hypotheses. South African Journal of Wildlife
Research, 39(2), 109e125.
Hayward, M. W., & Somers, M. (2009). Reintroduction of top-order predators. Chi-
chester, U.K.: J. Wiley.
Hilborn, A., Pettorelli, N., Orme, C. D. L., & Durant, S. M. (2012). Stalk and chase: How
hunt stages affect hunting success in Serengeti cheetah. Animal Behaviour,
84(3), 701e706.
Hothorn, T., Bretz, F., & Westfall, P. (2008). Simultaneous inference in general
parametric models. Biometrical Journal, 50(3), 346e363.
Jarman, P. (1974). The social organisation of antelope in relation to their ecology.
Behaviour, 48(1), 215e267.
Krause, J., & Ruxton, G. D. (2002). Living in groups. Oxford, U.K: Oxford University
Press.
Kronfeld-Schor, N., & Dayan, T. (2003). Partitioning of time as an ecological
resource. Annual Review of Ecology, Evolution, and Systematics, 34,153
e181.
Laundr
e, J. W., Hern
andez, L., & Altendorf, K. B. (2001). Wolves, elk, and bison:
Reestablishing the landscape of fearin Yellowstone National Park, USA. Ca-
nadian Journal of Zoology, 79(8), 1401e1409.
Laundr
e, J. W., Hern
andez, L., & Ripple, W. J. (2010). The landscape of fear: Ecological
implications of being afraid. Open Ecology Journal, 3,1e7.
Lima, S. L., & Bednekoff, P. A. (1999). Temporal variation in danger drives anti-
predator behavior: The predation risk allocation hypothesis. American Natu-
ralist, 153(6), 649e659.
Lima, S. L., & Dill, L. M. (1990). Behavioral decisions made under the risk of pre-
dation: A review and prospectus. Canadian Journal of Zoology, 68(4), 619e640.
Linkie, M., & Ridout, M. (2011). Assessing tigereprey interactions in Sumatran
rainforests. Journal of Zoology, 284(3), 224e229.
Loveridge, A. J., Hunt, J. E., Murindagomo, F., & Macdonald, D. W. (2006). Inuence of
drought on predation of elephant (Loxodonta africana) calves by lions (Panthera
leo) in an African wooded savannah. Journal of Zoology, 270(3), 523e530.
Makin, D. F.. (n.d.) [Cheetah and wild dog prey kill data, Tswalu Kalahari Reserve].
Unpublished raw data.
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231230
Marker, L., Dickman, A., Wilkinson, C., Schumann, B., & Fabiano, E. (2007). The
namibian cheetah: Status report. Cat News, 3,4e13.
Middleton, A. D., Kauffman, M. J., McWhirter, D. E., Jimenez, M. D., Cook, R. C.,
Cook, J. G., et al. (2013). Linking anti-predator behaviour to prey demography
reveals limited risk effects of an actively hunting large carnivore. Ecology Letters,
16, 1023e1030.
Ndaimani, H., Tagwireyi, P., Sebele, L., & Madzikanda, H. (2016). An ecological
paradox: The African wild dog (Lycaon Pictus) is not attracted to water points
when water is scarce in Hwange National Park, Zimbabwe. PloS One, 11(1),
e0146263.
Ogutu, J. O., Reid, R. S., Piepho, H.-P., Hobbs, N. T., Rainy, M. E., Kruska, R. L., et al.
(2014). Large herbivore responses to surface water and land use in an East
African savanna: Implications for conservation and human-wildlife conicts.
Biodiversity and Conservation, 23(3), 573e596.
Padi
e, S., Morellet, N., Hewison, A., Martin, J. L., Bonnot, N., Cargnelutti, B., et al.
(2015). Roe deer at risk: Teasing apart habitat selection and landscape con-
straints in risk exposure at multiple scales. Oikos, 124(11), 1536e1546.
P
eriquet, S., Valeix, M., Loveridge, A. J., Madzikanda, H., Macdonald, D. W., & Fritz, H.
(2010). Individual vigilance of African herbivores while drinking: The role of
immediate predation risk and context. Animal Behaviour, 79(3), 665e671.
Pomilia, M. A., McNutt, J. W., & Jordan, N. R. (2015). Ecological predictors of African
wild dog ranging patterns in northern Botswana. Journal of Mammalogy,1e10.
Preisser, E. L., Orrock, J. L., & Schmitz, O. J. (2007). Predator hunting mode and
habitat domain alter nonconsumptive effects in predatoreprey interactions.
Ecology, 88(11), 2744e2751.
Reiczigel, J., Lang, Z., R
ozsa, L., & T
othm
er
esz, B. (2008). Measures of sociality: Two
different views of group size. Animal Behaviour, 75(2), 715e721.
Rovero, F., Jones, T., & Sanderson, J. (2005). Notes on Abbott's duiker (Cephalophus
spadix True 1890) and other forest antelopes of Mwanihana Forest, Udzungwa
Mountains, Tanzania, as revealed by camera-trapping and direct observations.
Tropical Zoology, 18(1), 13e23.
Roxburgh, D. J. (2008). Prey and range use of lions on Tswalu Kalahari Reserve. [M.Sc.
thesis]. Pretoria, South Africa: University of Pretoria.
Schmitt, M. H., Stears, K., Wilmers, C. C., & Shrader, A. M. (2014). Determining the
relative importance of dilution and detection for zebra foraging in mixed-
species herds. Animal Behaviour, 96,151e158.
Schmitz, O. J. (2007). Predator diversity and trophic interactions. Ecology, 88,
2415e2426.
Shrader, A. M., Brown, J. S., Kerley, G. I. H., & Kotler, B. P. (2008). Do free-ranging
domestic goats show landscapes of fear? Patch use in response to habitat
features and predator cues. Journal of Arid Environments, 72(10), 1811e1819.
http://dx.doi.org/10.1016/j.jaridenv.2008.05.004.
Sinclair, A., Mduma, S., & Brashares, J. S. (2003). Patterns of predation in a diverse
predatoreprey system. Nature, 425(6955), 288e290.
Tambling, C. J., Minnie, L., Meyer, J., Freeman, E. W., Santymire, R. M., Adendorff, J.,
et al. (2015). Temporal shifts in activity of prey following large predator rein-
troductions. Behavioral Ecology and Sociobiology, 69(7), 1153e1161.
Team, R. C. (2014). R: A language and environment for statistical computing. Vienna,
Austria: R Foundation for Statistical Computing. http://www.RStudio.com.
Thaker, M., Vanak, A. T., Owen, C. R., Ogden, M. B., Niemann, S. M., & Slotow, R.
(2011). Minimizing predation risk in a landscape of multiple predators: Effects
on the spatial distribution of African ungulates. Ecology, 92(2), 398e407.
Valeix, M., Fritz, H., Loveridge, A. J., Davidson, Z., Hunt, J. E., Murindagomo, F., et al.
(2009). Does the risk of encountering lions inuence African herbivore
behaviour at waterholes? Behavioral Ecology and Sociobiology, 63(10),
1483e1494.
Valeix, M., Loveridge, A., Chamaill
e-Jammes, S., Davidson, Z., Murindagomo, F.,
Fritz, H., et al. (2009). Behavioral adjustments of African herbivores to predation
risk by lions: Spatiotemporal variations inuence habitat use. Ecology, 90(1),
23e30.
Valeix, M., Loveridge, A. J., Davidson, Z., Madzikanda, H., Fritz, H., &
Macdonald, D. W. (2010). How key habitat features inuence large terrestrial
carnivore movements: Waterholes and African lions in a semi-arid savanna of
north-western Zimbabwe. Landscape Ecology, 25(3), 337e351.
Van Rooyan, N. (1999). The vegetation types and veld condition of Tswalu Private
Desert Reserve. Unpublished Report to the Management of Tswalu Kalahari
Reserve.
Venables, W. N., & Ripley, B. D. (2002). Random and mixed effects. In
W. N. Venables, & B. D. Ripley (Eds.), Modern Applied Statistics with S (pp.
271e
300). New York, NY: Springer.
D. F. Makin et al. / Animal Behaviour 127 (2017) 225e231 231
... Les recherches conduites sur les zèbres des plaines se sont initialement focalisées sur leur organisation sociale (Klingel 1969b, Penzhorn 1984, Rubenstein 1986) et leur reproduction (Klingel 1969a, Smuts 1976b. Le comportement des zèbres des plaines a été documenté en 1974 par Klingel et de nombreux travaux de recherche sur ce sujet ont suivi : des études se sont par exemple intéressées au budget d'activité (Neuhaus and Ruckstuhl 2002), au leadership (Fischhoff et al. 2007a), à la sélection de l'habitat (Fischhoff et al. 2007b, Courbin et al. 2016, Makin et al. 2017, Patin 2018, Mandinyenya et al. 2020, aux comportements d'infanticide par les mâles (Pluháček and Bartoš 2000, Pluháček et al. 2006, Ransom and Kaczensky 2016, à la vigilance (Simpson et al. 2012, Schmitt et al. 2014, Creel et al. 2014, Barnier et al. 2016, Makin et al. 2017, Périquet et al. 2017) et à l'acquisition des ressources (Barnier et al. 2014, Creel et al. 2014, Périquet et al. 2017. Cependant, l'effet de la taille de groupe sur le comportement des zèbres des plaines a rarement été investigué (Schmitt et al. 2014, Périquet et al. 2017 (Smuts 1976a, Georgiadis et al. 2003, Grange et al. 2004, de Vos et al. 2020. ...
... Les recherches conduites sur les zèbres des plaines se sont initialement focalisées sur leur organisation sociale (Klingel 1969b, Penzhorn 1984, Rubenstein 1986) et leur reproduction (Klingel 1969a, Smuts 1976b. Le comportement des zèbres des plaines a été documenté en 1974 par Klingel et de nombreux travaux de recherche sur ce sujet ont suivi : des études se sont par exemple intéressées au budget d'activité (Neuhaus and Ruckstuhl 2002), au leadership (Fischhoff et al. 2007a), à la sélection de l'habitat (Fischhoff et al. 2007b, Courbin et al. 2016, Makin et al. 2017, Patin 2018, Mandinyenya et al. 2020, aux comportements d'infanticide par les mâles (Pluháček and Bartoš 2000, Pluháček et al. 2006, Ransom and Kaczensky 2016, à la vigilance (Simpson et al. 2012, Schmitt et al. 2014, Creel et al. 2014, Barnier et al. 2016, Makin et al. 2017, Périquet et al. 2017) et à l'acquisition des ressources (Barnier et al. 2014, Creel et al. 2014, Périquet et al. 2017. Cependant, l'effet de la taille de groupe sur le comportement des zèbres des plaines a rarement été investigué (Schmitt et al. 2014, Périquet et al. 2017 (Smuts 1976a, Georgiadis et al. 2003, Grange et al. 2004, de Vos et al. 2020. ...
Thesis
Chez les espèces sociales, les coûts et bénéfices de la vie en groupe sont nombreux et dynamiques, et la balance entre ces derniers est un déterminant clé de la taille des groupes. La taille de groupe est un composant de la socialité qui peut avoir d’importants effets sur le comportement des individus, leurs paramètres démographiques et leur dynamique sociale (mouvements intergroupes des individus, associations entre groupes). Cependant, ces effets restent mal compris. Dans cette thèse, j’explore l’effet de la taille de groupe sur le comportement, la démographie et la dynamique sociale du zèbre des plaines Equus quagga dans les populations sauvages du Parc National de Hwange (HNP, Zimbabwe) et du Parc de Hluhluwe-iMfolozi (HiP, Afrique du Sud). Dans le premier chapitre, je montre qu’à HNP la taille de groupe a peu d’effet sur la vigilance individuelle et l’acquisition des ressources, et n’a pas d’effet significatif sur la survie des individus, ce qui suggère que les effets de dilution et de détection importent peu sur le plan comportemental et démographique dans cette population. Dans le second chapitre, je montre que la probabilité qu’il y ait un changement d’étalon au sein des harems augmente lorsque le nombre de femelles reproductrices dans les harems augmente à HNP, mais que ces changements d’étalon n’affectent pas la survie des poulains. Ainsi, si le comportement d’infanticide par les mâles existe chez le zèbre des plaines en milieu sauvage, il devrait être très rare et ne pas avoir d’impact important sur la survie des poulains à l’échelle de la population. Enfin, dans le troisième chapitre, je montre que le nombre de femelles reproductrices dans les harems n’a pas d’effet sur la probabilité des harems à être observés seuls ou avec d’autres harems. En revanche, les harems comprenant davantage de femelles reproductrices semblent être moins souvent observés avec des groupes de mâles célibataires (bien que des incertitudes demeurent). Cela suggère que les harems comprenant beaucoup de femelles reproductrices pourraient éviter de s’associer avec les mâles célibataires, et semblent mieux réussir à les éviter à HiP où la végétation est globalement plus fermée qu’à HNP. De ce fait, la probabilité qu’il y ait un changement d’étalon au sein des harems n’augmente pas avec le nombre de femelles reproductrices dans les harems à HiP. Globalement, cette thèse remet en question le fonctionnement de l'effet de dilution et souligne l'importance de considérer l'effet régulateur potentiel des dynamiques sociales sur les populations, à travers leur effet sur la distribution spatiale des groupes.
... Although almost all prey live with many types of predators in their habitats (GriVen 2006), most experimental studies of predation have examined the effects of only one predator at a time (Sih et al. 1998;Ahlgren and Brönmark 2012). Several recent papers have suggested that multiple predators have effects on prey that cannot be predicted simply by summing the effects of single predator types (Alcaraz and Arce 2017;Makin et al. 2017;Blake et al. 2018). Because predator-induced defenses may lower the encounter rate and/or increase the chance of surviving a predator attack, when used against other predators, the same defenses may be useless or even increase predation risk (Petrin et al. 2010;Ahlgren and Brönmark 2012). ...
... Predators with different hunting modes may have varying levels of NCEs acting on prey (Preisser et al. 2007;Alcaraz and Arce 2017;Makin et al. 2017). For instance, it has been suggested that cues from ambush predators should be more indicative of imminent predation risk and thereby evoke stronger NCEs than cues from more widely ranging active hunting predators (Preisser et al. 2007). ...
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Wildlife are increasingly being found in urban habitats, and likely rely on some resources in suburban household yards, which exposes them to the effects of yard management and human and pet activities. We compared the relationships between these potential disturbances and benefits to the number of different types of wildlife sighted by householders, using written surveys. Owing to the inability of many household respondents to identify animals to the species or genus level, each different ‘type’ of animal individually listed was counted to generate the total number of types of wildlife observed by each household. We found that relatively more types of wildlife were observed by residents whose yards provided ease of faunal access under or through fences, had reduced pesticide use, increased levels of anthropogenic noise, and increased presence of pets in yards. The latter two associations likely relate to the increased opportunities to observe wildlife in yards that each creates. We also investigated the use of yards by wildlife and domestic pets in open compared to more vegetated habitats by day and night, using motion-sensor cameras. All animals observed were compared to the activity of introduced brown and black rats (Rattus norvegicus, R. rattus), owing to their wild origins but long commensal history with humans. Camera images indicated that animals’ natural activity periods were maintained in yards. Brown antechinuses (Antechinus stuartii), northern brown bandicoots (Isoodon macrourus), domestic cats (Felis catus) and native birds (species as listed below) each preferred sheltered or vegetated habitats over open habitats, when compared to the introduced rats that showed little habitat preference. However, unlike the other species, the native birds used open areas more than vegetated or sheltered areas when compared within their group only. The common brushtail possum (Trichosurus vulpecula) was observed to use open areas comparatively more than the introduced rats, but used vegetated or sheltered habitats more when compared to self only. The domestic dog (Canis familiaris) and red fox (Vulpes vulpes) used open areas more than vegetated or sheltered areas, when compared to the introduced rats, and against themselves. This indicated a level of coping with urban stressors by the native animals, but with a reliance on more vegetated habitats to allow for natural stress-relieving behaviours of escape or hiding. Here, we offer insights into how each of these findings may be used to help educate and motivate increased household responsibility for urban wildlife conservation.
... Temporal changes in activity may also occur if perceived risks from stressors are high and resources are available at alternative times (e.g., Makin et al., 2017;Wu et al., 2018;Smith et al., 2019). However, high activity overlaps between species, including predators and prey, are likely if the ecosystem can support the diversity of species present (Kronfeld-Schor and Dayan, 2003). ...
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Urban environments provide the only or best habitats that are left for wildlife in many areas, promoting increased interest in urban conservation and a need to understand how wildlife cope with urban stressors, such as altered predator activity and human disturbance. Here, we used filmed giving-up density experiments to investigate behavioral coping responses of foraging small prey animals at three sites (close, mid, and far) along an urban disturbance gradient. Our study design included “natural” and experimentally added stressor cues of predators and/or human disturbance. We observed small mammal foraging behaviors, particularly: the common brushtail possum ( Trichosurus vulpecula ), northern brown bandicoot ( Isoodon macrourus ), brown antechinus ( Antechinus stuartii ), black rat ( Rattus rattus ), and brown rat ( Rattus norvegicus ), and to a lesser degree several species of native birds. We found that at the close urban-edge environment, coping responses to human disturbances were most pronounced, and predator cues from the red fox ( Vulpes vulpes ) were perceived as least risky. However, at the mid environment, red fox cues were perceived as most risky, especially when combined with human disturbance. At the far environment, domestic cat ( Felis catus ) cues were perceived as most risky, again when combined with human disturbance. Impacts from the combined stressors of predator and human disturbance cues appeared to be additive, with higher risk being perceived with increasing distance from urban build-up. Behavioral adjustments were observed to be the primary response to stressors by small prey animals in the close environment. In the mid environment, slight temporal shifts in activity across the night were more evident. In the far environment, habitat components were likely being used differently as the primary coping response to stressors. As mostly the same species were observed along the disturbance gradient, our results suggest a level of response plasticity that is calibrated to the level of exposure to a stressor and the stressor type. To maximize conservation outcomes in urban habitats, we therefore propose that management should be sensitive to the level and history of human disturbance, as this affects the coping responses of wildlife that remain.
... Similarly, authors previously showed that mouflon were able to shift foraging activities from daytime to nocturnal hours as a strategy to avoid intense and temporally predictable human activities . Since mouflon crossed segments of ALF during night-time, irrespective of the level of use by humans during the day (Makin et al., 2017), the intensity of frequentation influences the probability of crossing on the scale of the whole day and therefore the habitat use. ...
Thesis
Les effets des changements globaux sur les habitats naturels sont de plus en plus perceptibles, et comprendre comment les animaux y répondent est nécessaire pour une meilleure gestion de leurs populations. C’est en effet à travers leur impact sur l’environnement, et essentiellement sur les habitats, que les activités humaines ont souvent le plus grand effet sur les écosystèmes, à travers le changement climatique, la fragmentation, la destruction de l'habitat, les changements dans l'utilisation des terres ou la surexploitation des ressources. Les ongulés constituent un exemple marquant de progression numérique et spatiale d’une guilde d’espèces dans des écosystèmes impactés par l’Homme. Cet essor démographique est à l’origine d’un nombre croissant d’interactions entre Homme et faune et place la gestion de ces espèces au cœur des préoccupations des politiques publiques. Dans ce contexte, j’ai étudié cinq espèces de grands ongulés sauvages : le chamois, le mouflon, le bouquetin, le chevreuil et le cerf, dans le cadre du projet Mov-It (Ungulates MOVing across heterogeneous landscapes: identifying behavioural processes linking global change to spatially-explicIT demographic performance and management), soutenu par l’Agence Nationale de la Recherche (ANR). Dans un premier temps, je mets en évidence les liens entre variations intraspécifiques de la taille du domaine vital saisonnier des ongulés, le paysage (i.e. les ressources, le risque et l’hétérogénéité) et les traits d’histoire de vie de ces espèces. Je me suis ensuite intéressée plus particulièrement à l’influence des structures linéaires anthropiques et naturelles du paysage sur l'utilisation individuelle de l'espace. Je montre ainsi que les grands herbivores utilisent des structures linéaires du paysage pour délimiter leur domaine vital mensuel, mais que l'importance relative de ces structures linéaires dans la délimitation du domaine vital mensuel diminuait à mesure que leur densité augmentait dans le paysage local. Je mets également en évidence le caractère risqué des structures anthropiques pour les ongulés, en particulier l'effet de l'intensité de l’utilisation humaine de ces structures sur le nombre de traversées par les mouflons. Enfin, l’importance de la prise en compte du paysage du risque et des ressources sur l’organisation sociale est démontré. En effet, la formation de dyades (i.e. paires d’individus) est plus probable dans les milieux ouverts riche en ressources et lorsque le risque, incluant prédation et dérangement, est le plus fort (i.e. le jour). L’ensemble des résultats présentés dans ce travail de thèse a permis d’améliorer notre compréhension des effets de la structure du paysage et de la socialité sur la sélection d’habitat et le mouvement chez différentes espèces d’ongulés.
... Being Canids, coyotes should be well equipped to locate carrion directly based on the presence of strong olfactory and visual cues (Danner & Smith, 1980;Kamler et al., 2004;Natusch et al., 2017), but coyotes may be limited in their ability to detect mountain lions. Mountain lions are stalk-and-ambush predators (Beier et al., 1995), and should be difficult to perceive directly, but should occupy somewhat predictable habitats (Makin et al., 2017;Preisser et al., 2007) and thus be more perceptible via indirect means. Coyotes navigating risky areas may be better equipped to identify habitats (i.e., indirect assessment) frequented by mountain lions, than the exact location of a mountain lion itself (i.e., direct assessment). ...
Article
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Successfully perceiving risk and reward is fundamental to the fitness of an animal, and can be achieved through a variety of perception tactics. For example, mesopredators may “directly” perceive risk by visually observing apex predators, or may “indirectly” perceive risk by observing habitats used by predators. Direct assessments should more accurately characterize the arrangement of risk and reward; however, indirect assessments are used more frequently in studies concerning the response of GPS‐marked animals to spatiotemporally variable sources of risk and reward. We investigated the response of a mesopredator to the presence of risk and reward created by an apex predator, where risk and reward likely vary in relative perceptibility (i.e., degree of being perceptible). First, we tested whether coyotes (Canis latrans) use direct or indirect assessments to navigate the presence of mountain lions (Puma concolor; risk) and kills made by mountain lions (reward) in an area where coyotes were a common prey item for mountain lions. Second, we assessed the behavioral response of coyotes to direct encounters with mountain lions. Third, we evaluated spatiotemporal use of carrion by coyotes at kills made by mountain lions. Indirect assessments generally outperformed direct assessments when integrating analyses into a unified framework; nevertheless, our ability to detect direct perception in navigating to mountain lion kills was likely restricted by scale and sampling limitations (e.g., collar fix rates, unsampled kill sites). Rather than responding to the risk of direct encounters with mountain lions, coyotes facilitated encounters by increasing their movement rate, and engaged in risky behavior by scavenging at mountain lion kills. Coyotes appear to mitigate risk by using indirect perception to avoid mountain lions. Our predator–predator interactions and insights are nuanced and counter to the conventional predator–prey systems that have generated much of the predation risk literature. Successfully perceiving risk and reward can be achieved through direct or indirect cues. First, we tested whether coyotes (Canis latrans) use direct or indirect assessments to navigate the presence of mountain lions (Puma concolor; risk) and kills made by mountain lions (reward) in an area where coyotes were a common prey item for mountain lions. Second, we assessed the behavioral response of coyotes to direct encounters with mountain lions. Third, we evaluated spatiotemporal use of carrion by coyotes at kills made by mountain lions.
... For example, in pronghorns (Antilocapra americana), Kitchen (1974) showed a positive correlation between forage quality in a territory and either the average number of females present or the mating success of males. With respect to top-down mechanisms, species can alter their habitat use in response to predation risk, avoid areas of high quality or quantity of forage to increase safety (Creel et al. 2005), change temporal and spatial patterns of habitat use (Valeix et al. 2009;Riginos 2015;Palmer et al. 2017), increase vigilance and reduce foraging time (Creel et al. 2014) and change group size (Makin et al. 2017). ...
Article
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The factors that regulate the abundance and distribution of wild herbivores are key components of a species’ ecology and include bottom-up and top-down mechanisms, as well as aspects related to social organization. In territorial ungulates, males distribute themselves to enhance access to females by anticipating how resources will influence female distribution. Although the variables that influence the distribution of territorial males have implications for mating opportunities and reproductive success, these relationships remain largely unknown. We assessed how bottom-up, top-down and social factors influence the spatial distribution of territorial male guanacos (Lama guanicoe) in a semiarid ecosystem during three periods of the reproductive season, in a population with two alternative mating tactics: a resource-defence tactic adopted by family group males and a clustered territorial tactic adopted by solitary males. We conducted ground surveys of males from both social units and used density surface models to assess the influence of primary productivity, predation risk and female grouping on their spatial distribution. Our results showed that territorial males were more abundant in areas of increased primary productivity during the group formation period in years of good plant growth and higher number of females/female groups throughout the reproductive season, suggesting that both bottom-up and social traits regulate their spatial distribution. Predation risk did not significantly influence the abundance of territorial males. Overall, our research contributes to the understanding of territorial systems in ungulates and reinforces the current theory that bottom-up processes are relatively more important than top-down processes in regulating populations of large herbivores. Significance statement Many factors operate together to regulate the abundance and spatial distribution of territorial ungulates. Understanding these relationships has implications for mating opportunities and reproductive success. In this study, we combined field data with density surface models to assess the influence of bottom-up, top-down and social factors on the spatial distribution of a territorial ungulate during the reproductive season. We used the guanaco (Lama guanicoe), the main wild ungulate of the southern region of South America, as a study model. Our results suggest that in low-productivity environments, bottom-up (primary productivity) and social traits (female grouping) predominate in regulating the spatial distribution of territorial male guanacos, rather than top-down factors (predation risk). We highlight the possibility that different populations of herbivores respond differently depending on environmental conditions that shape both the quality and quantity of forage and predation.
... Different behavioral categories are hypothesized to have contrasting functions (Table 1), such as alerting conspecifics to imminent risk [3,4], informing predators that they have been detected [5,6], signaling high levels of physical fitness [1,2,7], monitoring or detecting additional predators [8,9], diluting individual predation risk [10][11][12], or fleeing the immediate area [13,14]. As predators vary in key traits which may render particular responses more or less effective [15][16][17], the anti-predator behaviors performed may be chosen based on the specific threat faced [13,18,19]. However, we still know little about which elements of predatory threat shape variation in reactive anti-predator strategies in large mammals [1,2]. ...
Article
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Large mammalian herbivores use a diverse array of strategies to survive predator encounters including flight, grouping, vigilance, warning signals, and fitness indicators. While anti-predator strategies appear to be driven by specific predator traits, no prior studies have rigorously evaluated whether predator hunting characteristics predict reactive anti-predator responses. We experimentally investigated behavioral decisions made by free-ranging impala, wildebeest, and zebra during encounters with model predators with different functional traits. We hypothesized that the choice of response would be driven by a predator’s hunting style (i.e., ambush vs. coursing) while the intensity at which the behavior was performed would correlate with predator traits that contribute to the prey’s relative risk (i.e., each predator’s prey preference, prey-specific capture success, and local predator density). We found that the choice and intensity of anti-predator behaviors were both shaped by hunting style and relative risk factors. All prey species directed longer periods of vigilance towards predators with higher capture success. The decision to flee was the only behavior choice driven by predator characteristics (capture success and hunting style) while intensity of vigilance, frequency of alarm-calling, and flight latency were modulated based on predator hunting strategy and relative risk level. Impala regulated only the intensity of their behaviors, while zebra and wildebeest changed both type and intensity of response based on predator traits. Zebra and impala reacted to multiple components of predation threat, while wildebeest responded solely to capture success. Overall, our findings suggest that certain behaviors potentially facilitate survival under specific contexts and that prey responses may reflect the perceived level of predation risk, suggesting that adaptive functions to reactive anti-predator behaviors may reflect potential trade-offs to their use. The strong influence of prey species identity and social and environmental context suggest that these factors may interact with predator traits to determine the optimal response to immediate predation threat.
Article
Experiments have begun demonstrating that the fear (antipredator behavioral responses) large carnivores inspire in ungulates can shape ecosystem structure and function. Most such experiments have focused on the impacts of either just one large carnivore, or all as a whole, rather than the different impacts different large carnivores may have in intact multi-predator-prey systems. Experimentally testing the relative fearfulness ungulates demonstrate toward different large carnivores is a necessary first step in addressing these likely differing impacts. We tested the fearfulness ungulates demonstrated to playbacks of lion (Panthera leo), African wild dog (Lycaon pictus), cheetah (Acinonyx jubatus) or non-predator control (bird) vocalizations, in Greater Kruger National Park, South Africa. Ungulates ran most to lions, then wild dogs, and then cheetahs, demonstrating a very clear hierarchy of fear. Those that did not run looked toward the sound more on hearing large carnivores than controls, looking most on hearing lions. Notably, prey species-specific population level kill rates by each predator did not predict the patterns observed. Our results demonstrate that different large carnivores inspire different levels of fear in their ungulate prey, pointing to differing community-level impacts, which we discuss in relation to the ongoing worldwide decline and loss of large carnivores.
Article
Spatiotemporal variation in predation risk arises from interactions between landscape heterogeneity, predator densities, and predator hunting mode, generating landscapes of fear for prey species that can have important effects on prey behaviour and ecosystem dynamics. As widespread apex predators, humans present a significant source of risk for hunted animal populations. Spatiotemporal patterns of risk from hunters can be overlapping or contrast with patterns of risk from other predators. Human infrastructure can also reshape spatial patterns of risk by facilitating or impeding hunter or predator movement, or deterring predators that are themselves wary of humans. We examined how anthropogenic and natural landscape features interact with hunting modes of rifle hunters and mountain lions (Puma concolor) to generate patterns of spatiotemporal risk for their primary prey. We explored the implications of human‐modified landscapes of fear for Columbian black‐tailed deer (Odocoileus hemionus columbianus) in Mendocino County, California. We used historical harvest records, hunter GPS trackers, and camera trap records of mountain lions to model spatiotemporal patterns of risk for deer. We then used camera traps to examine deer spatial and temporal activity patterns in response to this variation in risk. Hunters and mountain lions exhibited distinct, contrasting patterns of spatiotemporal activity. Risk from rifle hunters, who rely on long lines of sight, was highest in open grasslands and near roads and was confined to the daytime. Risk from mountain lions, an ambush predator, was highest in dense shrubland habitat, farther from developed areas, and during the night and crepuscular periods. Areas of human settlement provided a refuge from both hunters and mountain lions. We found no evidence that deer avoided risk in space at the scale of our observations, but deer adjusted their temporal activity patterns to reduce the risk of encounters with humans and mountain lions in areas of higher risk. Our study demonstrates that interactions between human infrastructure, habitat cover, and predator hunting mode can result in distinct spatial patterns of predation risk from hunters and other predators that may lead to trade‐offs for prey species. However, distinct diel activity patterns of predators may create vacant hunting domains that reduce costly trade‐offs for prey. Our study highlights the importance of temporal partitioning as a mechanism of predation risk avoidance.
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In dry biomes, spatio-temporal variation in surface water resource stocks is pervasive, with unknown effects on the ranging behaviour of large predators. This study assessed the effect of spatial variation in surface water resources on the ranging behaviour of the African wild dog (Lycaon pictus). We analyzed data for 1992 (dry year with 20 water points) and 2000 (wet year with 30 water points) against presence-only data for five packs of L. pictus in a part of Hwange National Park and adjacent smallholder communal farming areas in western Zimbabwe. Modelling the potential habitat for L. pictus using Maxent with distance from water points (Dw) and Normalized Difference Vegetation Index (NDVI) as predictor variables was successful for 2000 (AUC = 0.793) but not successful for 1992 (AUC = 0.423), with L. pictus probability of occurrence near water points being more for year 2000 than for year 1992. The predicted L. pictus range was wider in 1992 (~13888.1 km2) than in 2000 (~958.4 km2) (Test of Proportions, χ2 = 124.52, df = 1, P = 0.00). Using the 2nd order Multitype Nearest Neighbour Distance Function (Gcross), we also observed significant attraction between L. pictus and water points within only ~1km radius for 1992 but up to ~8km radius for 2000. Our study reinforced the notion that surface water resources attract wild dogs in the savannahs but paradoxically less so when water resources are scarce. In particular, our study furthers current understanding of the effects of changing water availability regimes on the endangered L. pictus, providing evidence that the endangered predator's home range encroaches into potential ecological traps (i.e., smallholder communal farming areas) when water resources are scarce.
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The predator-prey space game and the costs associated with risk effects are affected by prey 1) proactive adjustments (when prey modify their behaviour in response to an a priori assessment of the risk level) and 2) reactive adjustments (when prey have detected an immediate threat). Proactive adjustments are generally well-studied, whereas the frequency, strength and duration of reactive adjustments remain largely unknown. We studied the space use and habitat selection of GPS-collared zebras Equus quagga from 2 to 48 h after an encounter with lions Panthera leo. Lion-zebra encounters generally occurred close to artificial waterholes (< 1 km). Two hours after an encounter, zebras were more likely to have fled than stay when the encounter occurred in more risky bushy areas. During their flight, zebras selected grasslands more than usual, getting great visibility. Regardless of their initial response, zebras finally fled at the end of the night and reached areas located far from waterholes where encounters with lions are less frequent. The large-scale flights (∼4-5 km) of zebras led to a local zebra depression for lions. Zebras that had fled immediately after the encounter resumed their behaviour of coming close to waterholes on the following day. However, zebras that had initially stayed remained far from waterholes for an extra 24 h, remaining an elusive prey for longer. The delay in the flight decision had different short-term consequences on the lion-zebra game. We reveal that the spatial context of the encounter shapes the immediate response of prey, and that encountering predators induces strong behavioural responses: prey flee towards distant, safer, areas and have a constrained use of key resource areas which are at the heart of the predator-prey game at larger spatio-temporal scales. Nighttime encounters were infrequent (once every 35 days on average), zebra responses were short-lived (< 36 h) but occurred over a large spatial scale (several km).
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Extinction risk in African wild dogs (Lycaon pictus) has been linked to their wide-ranging movement behavior. However, drivers of variability in African wild dog ranging are not well understood. This study examines the effects of intrinsic and extrinsic factors on ranging patterns and describes scale-dependent and intra-annual variation in the ranging of 5 packs of African wild dogs in the Okavango Delta from 2007 to 2010. 95% fixed kernel home ranges (X = 739 ± 81 km2) and daily step lengths (X = 8.5 ± 0.5 km) in this study are larger than have generally been reported for African wild dogs elsewhere. Little seasonal variation in daily ranging distances was observed despite home-range contractions during denning to 27% of packs’ ranges outside the denning period. During nondenning periods, litter size was the most influential driver of ranging patterns, with large litters associated with reduced pack movements and smaller home ranges at all temporal scales. Pack size was also a significant driver of home-range size (but not daily distance travelled) at weekly timescales, where larger packs utilized smaller ranges. Daily temperatures were inversely related to home-range size and step length at short timescales, while higher flood levels were related to reduced ranging distances at intermediate timescales. Our results indicate that extrinsic drivers of African wild dog ranging behavior tend to be scale dependent, while intrinsic factors may be more influential for ranging patterns than previously reported.
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The response of prey to predation risk varies through time and space. These responses relate to trade-offs between foraging and predator avoidance. Following the extirpation of predators from many landscapes, the responses related to predator avoidance may have been lost or diluted. Investigating the activity pattern of prey species on comparable landscapes with and without large predators provides an opportunity to understand how predators may shape prey activity and behaviour. Using camera trap data from neighbouring fenced sections of the Addo Elephant National Park (Eastern Cape, South Africa), we investigated the activity patterns of species exposed to large predators, where the predators were only present in one of the sections. Our results suggest that prey species at risk of predation (e.g., buffalo, kudu and warthog) are more likely to be active diurnally when co-existing with nocturnally active predators, thereby reducing the activity overlap with these predators. In the absence of predators, kudu and buffalo were more active at night resulting in a low overlap in activity between sections. Warthog activity was predominantly diurnal in both sections, resulting in a high overlap in activity between sections. The presence of predators reduced the nocturnal activity of warthogs from 6 to 0.6 % of all warthog captures in each section. Elephants, which are above the preferred prey weight range of the predators and therefore have a low risk of predation, showed higher overlap in activity periodicity between predator-present and predator-absent areas. Our findings suggest that maintaining prey with their predators has the added benefit of conserving the full spectrum of prey adaptive behaviours.
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Increasingly, the restoration of large carnivores is proposed as a means through which to restore community structure and ecosystem function via trophic cascades. After a decades-long absence, African wild dogs (Lycaon pictus) recolonized the Laikipia Plateau in central Kenya, which we hypothesized would trigger a trophic cascade via suppression of their primary prey (dik-dik, Madoqua guentheri) and the subsequent relaxation of browsing pressure on trees. We tested the trophic-cascade hypothesis using (1) a 14-year time series of wild dog abundance; (2) surveys of dik-dik population densities conducted before and after wild dog recovery; and (3) two separate, replicated, herbivore-exclusion experiments initiated before and after wild dog recovery. The dik-dik population declined by 33% following wild dog recovery, which is best explained by wild dog predation. Dik-dik browsing suppressed tree abundance, but the strength of suppression did not differ between before and after wild dog recovery. Despite strong, top-down limitation between adjacent trophic levels (carnivore- herbivore and herbivore-plant), a trophic cascade did not occur, possibly because of a time lag in indirect effects, variation in rainfall, and foraging by herbivores other than dik-dik. Our ability to reject the trophic-cascade hypothesis required two important approaches: (1) temporally replicated herbivore exclusions, separately established before and after wild dog recovery; and (2) evaluating multiple drivers of variation in the abundance of dik-dik and trees. While the restoration of large carnivores is often a conservation priority, our results suggest that indirect effects are mediated by ecological context, and that trophic cascades are not a foregone conclusion of such recoveries.
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Non-consumptive effects of predators result from the cost of responses to perceived risk. Prey modulate risk exposure through flexible habitat selection at multiple scales which, in interaction with landscape constraints, determines their use of risky habitats. Identifying the relative contributions of landscape constraints and habitat selection to risk exposure is a critical first step towards a mechanistic understanding of non-consumptive effects.Here, we provide an integrative multi-scale study of roe deer spatial responses to variable hunting pressure along a landscape gradient of open habitats and dispersed refuges. Between low-risk and high-risk periods, we investigated shifts in 1) home-range location, 2) probability of using risky habitats (between-habitat scale) and 3) distance to the nearest refuge (within-habitat scale). For 2) and 3), we disentangled the contributions of landscape constraints and habitat selection to risky habitat use.We found that when risk was high, roe deer did not shift their home-range, but generally decreased their use of risky habitats, and sometimes reduced their distance to cover (particularly older animals). There was a functional response in between-habitat selection, with animals living in more open landscapes responding more than those living in landscapes with more refuges. However, individuals living in more open landscapes avoided open risky habitat less. Finally, we found that among-individual variation in risk exposure was generally, but not always, minimized by habitat selection across gradients of landscape constraints.To our knowledge, this is the first study simultaneously documenting prey responses to risk at the within-habitat, between-habitat and home-range scales. Our results support the view that between-habitat selection acts at a higher hierarchical level than within-habitat selection, and provide a framework for disentangling the contributions of habitat selection and landscape constraints to risk exposure. Selection cannot always compensate for landscape constraints, indicating a need for further investigation of the processes underlying habitat selection.
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Predators alter prey dynamics by direct killing and through the costs of antipredator responses or risk effects. Antipredator behavior includes proactive responses to long-term variation in risk (e.g., grouping patterns) and reactive responses to short-term variation in risk (e.g., intense vigilance). In a 3-year field study, we measured variation in antipredator responses and the foraging costs of these responses for 5 ungulates (zebra, wildebeest, Grant’s gazelle, impala, and giraffe) that comprised more than 90% of the prey community available to the 2 locally dominant predators, lions and spotted hyenas. Using a model-selection approach, we examined how vigilance and group size responded to attributes of the predator, prey, and environment. We found that 1) the strength of antipredator responses was affected by attributes of the predator, prey, and environment in which they met; 2) grouping and vigilance were complementary responses; 3) grouping was a proactive response to the use of dangerous habitats, whereas vigilance was a reactive response to finer cues about predation risk; 4) increased vigilance caused a large reduction in foraging for some species (but not all); and 5) there was no clear relationship between direct predation rates and the foraging costs of antipredator responses. Broadly, our results show that antipredator responses and their costs vary in a complex manner among prey species, the predators they face, and the environment in which they meet.
Book
S-Plus is a powerful environment for statistical and graphical analysis of data. It provides the tools to implement many statistical ideas which have been made possible by the widespread availability of workstations having good graphics and computational capabilities. This book is a guide to using S-Plus to perform statistical analyses and provides both an introduction to the use of S-Plus and a course in modern statistical methods. All data sets and S-Plus functions used are supplied with the book on a diskette.
Chapter
We collect together several ways to handle linear and non-linear models with random effects, possibly as well as fixed effects.