African conservation areasyawning are
internationally sought out as destinations to
observe charismatic megafauna. Recently,
research has identified that wildlife can become
stressed at the presence of human observers and
tourists. We investigated the impact of tourist
presence and absence on the reintroduced lion
Panthera leo Linnaeus, 1758 population in Addo
Elephant National Park, South Africa, by
measuring the frequency of
disturbance-indicating (yawning, sitting,
standing, moving away) and relaxation-indicating
(rolling, grooming) behaviours when tourists
were present and absent. Lions were
significantly more likely to exhibit disturbance
behaviours when tourists were present, and
significantly more likely to perform relaxation
behaviours when tourists were absent. We also
measured the number of breaths per minute, as an
indicator of stress, and found that this also
increased in the presence of tourists. Lions
incur stress and an energetic cost (albeit
minor) from being observed by tourists. Some
lion populations may face this chronically,
which may increase their susceptibility to
disease by reducing their immunity. Enforcing
rules banning off-road driving in pursuit of
wildlife and ensuring adequate refuge away from
tourist infrastructure are important methods to
minimise the stressful impacts of tourists on
wildlife.
Introduction
Ecotourism is considered to offer
substantial benefits to biodiversity
conservation by yielding economic benefits to
lands that would otherwise have been managed
with little consideration for biodiversity
(Hayward 2005, Lindsey et al. 2005, 2009,
Norton-Griffiths 2007). Yet it is only recently
that the impact of ecotourism on the
biodiversity it is hypothesised to benefit has
been investigated (Kruger 2005). Similarly, the
subtle impacts of tourism, via sublethal
physiological effects, which may ultimately
reduce individual fitness and have population
consequences, are slowly becoming apparent
(Buckley 2001, McClung et al. 2004) suggesting
ecotourism is far from benign.
Ecotourism has been shown to have a range of
impacts on wildlife. For example, tourist
presence reduced body condition and health in
lizards (Amo et al. 2006). Fledgling penguins in
New Zealand are smaller and had lower survival
rates at ecotourism sites than sites without
tourists (McClung et al. 2004). Seabird nesting
behaviour was also affected by tourist presence
(Burger and Gochfeld 1993). Tourist presence
causes higher rates of disease mortality in
chimpanzees (Kondgen et al. 2008). Whale
watching affects the behaviour of marine
mammals, for example, dolphins Tursiops
truncatus are forced to reduce resting time and
remain active for longer periods in the presence
of permitted tourist boats (Constantine et al.
2003). Brown bears Ursus arctos altered their
foraging behaviour and, in some cases, food
intake in experiments of ecotourism impacts
(Rode et al. 2006). Tourists on snowmobiles
caused increased stress levels in wolves Canis
lupus and elk Cervus elaphus (Creel et al.
2002). Apart from the latter studies, very
little work has been done on the impacts of
ecotourism on wild terrestrial mammals, although
cheetah Acinonyx jubatus hunting behaviour was
affected by the presence of tourists (Eaton
1970).
Conservation in Africa is becoming
increasingly dependent upon the economic
benefits provided by ecotourism (Lindsey et al.
2005, 2009). Lions Panthera leo Linnaeus, 1758
are amongst the most sought after animals to
view by tourists (Boshoff et al. 2007, Lindsey
et al. 2007). Hence, any reduction in their
visibility by tourists could have economic
ramifications as tourists seek other sites where
lions are more visible. Ultimately, this would
reduce the economic benefits of ecotourism
ventures compared to agriculture and risk losing
the benefits of habitat conservation in private
lands that are necessary to conserve viable
populations of wildlife to sustain an ecotourism
venture (Lindsey et al. 2005, 2009).
Stress is known to increase breathing and
heart rate (Wareham et al. 1997, Eston et al.
1998), and hence energy expenditure (Cohen et
al. 1975), and ultimately reduce immunity to
disease (Ellenberg et al. 2006). There are
several behaviours of felids that may indicate
stress or discomfort. Yawning is a
behaviour that felids use to warn conspecifics
not to approach any closer (Estes 1999). Sitting
up from a lying/ sleeping position, standing and
moving indicate a readiness for activity that
can be caused by the approach of tourists or
their behaviour/noise. These behaviours also
incur an energetic cost, albeit minor, that may
not have occurred had the animal remained lying
or asleep. Conversely, grooming is a relaxation
behaviour in felids (Estes 1999). Breathing rate
is an indirect measure of energy expenditure
(Wareham et al. 1997, Eston et al. 1998) that we
used to measure the energetic costs of tourists
on lions. Similar physiological responses were
used to identify the impacts of tourists on
penguins (Ellenberg et al. 2006) and cheetahs
(Eaton 1974). In this study, we tested the
predictions that stress/warning (yawning)
and energetically costly behaviours like
sitting, standing and moving would be more
common when tourists were present, which would
be reflected in increased breathing rates; and
that relaxation behaviour (grooming) would be
more common when tourists were absent.
Discussion
Lions incur energetic costs (albeit minor)
attributable to the presence of tourists through
an increased frequency of energetically
expensive behaviour. The increased rate of
breathing is also an indicator of stress, which
may compound the impact of the increase in
disturbance related behaviours.
The impact of tourists on lions in Addo may
be an underestimate compared to other sites
throughout Africa. Addo has a relatively low
visitation rate (150 000 per year) and offers
dense vegetation that can act as a refuge for
lions from tourists (Bradfield 2005). Numerous
ecotourism sites around Africa have a much
higher visitation rate, which may increase the
frequency of lions being observed at close
proximity by tourists. Other sites are far more
open (notably the Serengeti &endash; Mara
ecosystem) and lions have little refuge habitat.
Private game reserves offer opportunities to
observe predators at very close proximity and
game drives can leave the road to follow moving
animals. This may mean that predators cannot get
refuge from harassment and may lead to much
greater behavioural modification and energetic
costs. There are rules to prevent this in most
state-owned conservation areas, however off-road
driving in pursuit of animals of interest is not
uncommon (MWH pers. obs.). While habituation
occurs, our observations suggest that lions can
discriminate between vehicles and possibly even
people within those vehicles (MWH pers. obs.),
so frequent presence of novel vehicles and
tourists is not likely to lead to habituation.
Habituation to game drive vehicles may occur,
but our results suggest habituation to private
tourist vehicles did not occur. It may not be
the vehicles themselves that causes stress,
rather the behaviour of the tourists within,
which included loud talking and leaning out of
windows.
While the stress and energetic impacts of
tourists on lions do not appear great and may
not have population-level consequences, it is
feasible that continued presence may lead to
chronic impacts and consequences. If these
impacts do become chronic, then wildlife may
become more susceptible to disease, which may
ultimately threaten small populations,
particularly those that are enclosed. While
stress has not been shown to have population
level consequences in lions, such impacts have
been observed in a range of penguin species
(Ellenberg et al. 2006).
Determining the actual impacts of human
observers is only possible by investigating
reproductive output and mortality, which require
study over much longer term than was possible in
this pilot study. Although lions are commonly
considered to be accustomed to tourists, the
significance of results obtained in this
preliminary study points at the fact that some
impact may be overlooked and it urges for more
detailed research in other areas. Recent
research suggests that other supposedly
resilient species are also impacted by human
presence (eg spotted hyaenas Crocuta crocuta in
the Masai Mara, Kenya; Kolowski and Holekamp
2008).
Strict adherence to roads is one way to
minimize tourist impacts, as well as ensuring
wildlife gets some refuge sites where they can
avoid humans. Spatial displacement of animals
into refuge from tourists can lead to excess
energetic costs however (Rode et al. 2006)
