Puma concolor. Source: U.S. National Park Service
The
Ecology and Conservation of Puma
concolor in
North America
The
cougar, Puma
concolor, is
a large American cat, up to 2.6 m in length, with a comparatively
small, rounded head with muscular jaws and characteristically rounded
ears. It has a uniformly beige coat; the uniformity of colour is
expressed in the cougar’s Latin name, concolor,
and differentiates it from any other American cat species, all of
which, for example the lynx, are patterned to some degree (Miller,
2007).
Taverna
et al.
(1990) describe the habitat of the cougar as being the most
wide-ranging of any large American carnivore, inhabiting rocky
outcrops, low to dense shrub, chaparral, and densely wooded areas.
Maehr et al.
(2004) even identifies shopping centres in Florida as viable habitat
for the cougar, where the animals exhibit similar traits to
populations living in naturally sparse landscapes.
The
cougar was once widespread throughout the whole of the United States
(Sweanor, et
al.,1999).
Human persecution forced the cougar into remote western regions,
effectively removing it from the eastern states.
P.
concolor has
a range encompassing 13 western states, while subspecies P.
concolor coryi
and P.
concolor stanleyana
exist in Florida (Maehr et
al., 2002).
Habitat
fragmentation, mainly by the building of roads is leading to cougar
ranges being limited (Beier, 1993), and a need for a minimum habitat
area study for cougars has been identified in order to properly
maintain cougar numbers in the face of social, industrial and
economic progress.
Husseman
et al. (2003)
found that wolves and cougars share a prey base. Elk form the main
prey item for wolves and cougars. Mule deer, bighorn sheep and
mountain goats make up the rest of the prey base. However, wolves
were found to be more likely to take juveniles of all prey species,
while cougars were able to take adults, reducing direct competition.
Beier
(1993) reported that the independent nature of adult female cougars
acted to regulate density, and that male density was separately
defined by the territorial nature of adult males. Female density is
primarily regulated by vegetative land cover, geological factors, and
prey accessibility, since it is her responsibility to raise young and
provide suitable cover and sustenance for them. Male numbers are
affected by competition for females, and so their range is partially
delimited by the same abiotic factors that influence distribution of
females. However, since ground cover is less of an issue for the
adaptable cougar, it is behaviours, particularly sexual and parental,
that govern range, with ranges being relative to those of other
adults, and density regulation may therefore been seen as an
extension of behavioural factors.
Population
dynamics are further affected by competition from bears and wolves,
where those species’ ranges overlap with cougar territories (Riley
et al.,
2004). Wolves are being actively reintroduced throughout the western
United States, and there is a projected conflict of interests between
both conserved species (Sweanor et
al., 2000).
White-tailed deer are colonising many valley locations in the western
states(Ripple, 2006), and these are being followed by cougars not
normally associated with valley environments. In fact, wolf
habitation of valleys may have affected cougar range at the time when
these two species were first learning to live together, and may have
been the deciding factor in limiting cougars to higher altitudes in
those areas.
The
recent cougar colonisation of valleys, such as those in Yellowstone
National Park, has led to confrontations between wolves and cougars,
in some cases leading to mortality in both species (Knopf, 2009).
Wolf conservation is therefore impacting on cougar regeneration,
forcing the cats to live in less desirable habitats, such as rocky
areas to which the cougars are better adapted than the wolves.
The
sampling and monitoring techniques currently employed by scientists
looking at the regeneration of P.
concolor in
North America are various and range from active trapping (Sweanor et
al., 2000)
to passive tracking (Miller, 2007).
Spring
activated animal snares were set up around Wyoming by Sweanor et
al. (2000)
to capture independent adults and mature cubs. These animals were
ear-tagged, radio-collared and marked with coded ear tattoos. In a
separate study in Florida, radio-tagged cougars were monitored by
aircraft (Maehr et
al., 2002)
Bounties
were regularly paid to cougar hunters (Knopf et
al., 2009;
Riley et al.,
2004), and although this practice has ceased, the term bounty
is still used to refer to hunted animals. However, cougars have been
reclassified as game animals and are still hunted in all states
except California and Oregon. Bag counts are currently limited to one
kill per day per season, and kills are recorded, leading to a
reliable system of cougar population assessment. Changes in hunting
style have led to conflict with new legislation, however: the
practice of treeing has been banned in all states except Texas
(Sweanor, et
al., 2000).
This entails hunting a cat with dogs until it runs up a tree. The cat
is then surrounded and shot at close range. Although curtailing overt
cruelty towards cougars, the ban on treeing has had the knock-on
effect of reducing the amount of time a hunter has to look at the
animal before killing it. Legislation limits the killing of females;
when treeing an animal, hunters could differentiate between males and
females and spare the latter. Now, however, both sexes are shot
indiscriminately.
A
roadkill survey in Florida by Lotz and Land (2007) estimated the
Florida cougar population and set out to discover the relationship
between road deaths and recorded births. The lowest annual estimate
of cougar births was determined by analysing birth and death rates of
known cougar populations as well as numbers of cougar bodies found on
local roads. It was found that the amount of Florida cougar roadkills
formed a set percentage of the total numbers of the cougar
population, suggesting that the roads were disturbing established
cougar ranges.
Cougars
have dog-like tracks (Miller, 2007), but a number of features easily
distinguish the two species. Kill sites can also identify predators:
kill efficiency, wound depth and length, subcutaneous haemorrhaging,
carcass entrance and covering of prey are all indicative of predator
identity.
Ever
since Europeans colonised the land mass now known as the United
States, any dangerous animal was considered fair game (Knopf et
al., 2009),
and could be destroyed to protect livestock as well as the settlers.
All wild animals were considered a food source in the early days of
the formation of the United States, so cougars may well have been
hunted for sustenance as well as for homeland security reasons.
Three
waves of cougar management have occurred in modern times: firstly, an
attempt at total annihilation, succeeded by managed sport hunting to
ameliorate livestock depredation, and finally an ostensibly concerted
effort to protect the cougar’s place in natural American ecosystems
(Riley, 2004).
It
has been demonstrated (Ripple et
al., 2006)
that the removal of cougars has allowed populations of their prey
species, particularly ungulates, to multiply exponentially. These
large numbers of unpredated ungulates in turn over-graze the native
herbaceous biomass, leading to the collapse of trophic cascades and
causing localised secondary extinctions.
However,
P. concolor
is now regaining some of its former North American territories
(Gloyne et
al., 2001;
Maehr et al.,
2002; Sweanor et
al., 2000).
This is due in large part to a relaxation of human persecution and a
coordinated effort on behalf of the majority of states (Knopf et
al., 2009),
with the notable exception of Texas, where cougars are regarded as a
pest species and hunting remains unregulated. Wildlife underpasses
are also being used in Florida to counter habitat fragmentation
(Lotz, M., Land, D., 2007) and are shown to be positively affecting
local cougar populations.
In
terms of habitat, the eastern regions of the United States present
large, viable ecosystems into which the cougar can be reinserted. The
cougar should be able to pick up its role as a top predator
relatively easily in those areas where habitat allows, and suitable
prey species still exist (Taverna, 1999). However, the cougar’s
main obstacle to reintroduction in Northern America is the public.
Beier (1991) suggests that the cougar’s negative image, caused
mainly by an increase in attacks on humans as the cougar’s range
extends towards concentrations of human habitation, could be
positively altered through information campaigns, and by providing
visitors to areas of known habitation with advice regarding possible
encounters.
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