THE INGREDIENTS
OF GOOD WILDLIFE MANAGEMENT
What makes a good wildlife
manager? Managers must understand the needs of
wildlife. He or she also needs to understand the
factors at work that make for good, healthy wildlife
populations.
HABITAT, for example, includes
all the things that wildlife and humans need for
life - air, food, water, shelter and space to live.
When these five habitat factors are in good supply
and arranged properly, they contribute to the
well-being of wildlife. When any of these factors is
in short supply, it may limit the kinds of animals,
the number of animals and where they're found. It is
then called a limiting factor.
The
ARRANGEMENT of food, cover, water and space
in an area determines wildlife types, numbers and
where you'll find them. The best arrangements are
those where all of these habitat factors occur in
small blocks that are close together with enough
space to meet the needs of the animals. Also,
animals tend to use the edge areas of food plots the
most, because these areas are the closest to cover.
CARRYING
CAPACITY is the number of animals an area can
support throughout the year without permanently
damaging the habitat or starving the animals. When
there are too many animals for the habitat, the
animals may eat too much of the vegetation that
makes up its food and cover. Once that vegetation is
gone, the habitat is damaged and the carrying
capacity of the area goes down. With less habitat or
poor habitat, the weaker animals will die from
disease, starvation, predators or other causes.
Fewer animals will be able to live there. As more
food and cover return, the carrying capacity goes up
again. Sometimes the vegetation is destroyed,
changing the habitat and carrying capacity.
SOCIAL
TOLERANCE is the number of animals a
landowner or the public will allow in an area. If
wildlife numbers exceed the acceptable or tolerable
levels - for example, if deer or elk are damaging a
farmer's crops - the animal numbers may need to be
reduced. Frequently, this tolerable level is below
the carrying capacity.
The
POPULATION DYNAMICS of a wildlife population
is the way its numbers go up and down over time. Two
major factors affect this - the BIRTH RATE and the
DEATH RATE.
Most wildlife species have a high
BIRTH RATE. In general, the smaller-sized species of
wildlife have higher birth rates than the larger
species.
The DEATH
RATE of most wildlife species is also high.
The smaller sized species of wildlife have higher
death rates than the larger species. Factors
affecting the death rate are:
Starvation, is directly related to
available food in their habitat.
Development/like housing, malls, other
buildings and roads can cut down the cover or
space in their habitat.
Climate extremes, such as cold, snowy
winters or dry, hot summers, can reduce wildlife
numbers.
Predation from other animals like bears,
mountain lions, coyotes, wolves, foxes, skunks,
raccoons, dogs.
Diseases and parasites can kill animals,
especially if the animals are already weak from
injuries or starvation.
Hunting in regulated seasons reduces
animal numbers.
Other human activities, such as animals
being hit by vehicles, getting tangled in
fences, poison, hitting power lines, being
caught in fires and poaching all take a toll on
wildlife and affect the death rate.
How and why do wildlife numbers
go up and down? Let's look at a situation that
generally occurs each year in deer populations.
Late in the spring, the animals
old enough to have bred the previous fall begin
having their young. With the existing animal herd
and their new fawns, the deer population reaches it
peak in the early summer. The population then begins
to decline because of the factors just identified as
affecting the death rate. The decline continues
through the rest of the summer, the fall, winter and
early spring of the following year. The remaining
adult and yearling animals that survived will start
the cycle all over again.
This cycle of birth and death
occurs every year. The cycle is the same for most
species of wildlife. Sometimes, if habitat
conditions are really good and the carrying capacity
goes up, animal populations will boom. At other
times, severe weather, disease, predators or
over-harvest by hunters can cause the population to
drop further than normal.
The job of the
WILDLIFE MANAGER is to
control the numbers of animals at, or just below,
the carrying capacity of their habitat while keeping
an eye on the overall ecosystem. That way, the
animals stand the best chance of staying healthy and
not harming their habitat. The wildlife manager must
also keep animal numbers within social tolerance -
the population level that people are willing to
tolerate.