Extinction of wildlife is the disappearance of wild animals brought about by
natural or unnatural means. The rapid disappearance of wildlife species was
ranked as one of the planet's gravest environmental worries, surpassing
pollution and global warming.
Over 34 000 plant species and 5200 animal species around the globe are
threatened with extinction and many thousands more become extinct each year. The
primary causes of species extinction or endangerment are habitat destruction,
commercial exploitation such as plant collecting, hunting and trade in animal
parts. Of these causes, direct habitat destruction threatens most species.
Many types of human activity result in habitat destruction. As species
evolve, they adapt to a specific habitat or
environment that best meets their survival needs. Without this habitat, the
species may not survive. Pollution, conversion of shrub lands to grazing lands,
cutting and clearing of forests, urbanisation, road and dam construction have
destroyed or seriously damaged available wildlife habitats.
Agriculture is another leading cause, with about 45 percent of the total land
area in many countries used for farming. Besides replacing natural habitat with
fields and plantations for the cultivation of crops, agricultural activity also
results in soil erosion, pollution from pesticides and fertilisers.
As for urban development, it has destroyed wild habitat areas as well. Like
agricultural activities, urbanisation has led to the direct replacement of
natural habitats. For instance, it causes the depletion
of local resources such as water. Shortage of water is detrimental to the
survival of many species. The cutting of forests for the clearance of land has
destroyed many important habitats for numerous species.
Numerous other forms of human activity result in habitat destruction and
degradation. These are grazing by domestic livestock reared by humans, mining
activities that degrade habitats through pollution and building of dams.
human recreational activity, particularly the use of off road vehicles, results
in the destruction of natural habitats.
Pollution is another important contributing cause of extinction. Water
pollution and increased water temperatures have wiped out species of fish in
many habitats. Oil spills contaminate the
ocean floor for many years after the event. Acid rain, which is the toxic result
of extreme air pollution, has been known to kill organisms in freshwater lakes
and destroy large tracts of forested land.
The warming of the Earth can alter habitats drastically, with serious
consequences for numerous species. It has caused expanses of evergreen forests
located immediately south of the tundra to shrink. Another effect is the
shifting of forests and grasslands towards more appropriate climate regimes.
However, animal species cannot shift their ranges quickly enough, so they have
no habitat to shift into.
The extinction of wildlife species is indeed a serious matter. Therefore,
preventing it is of utmost importance.