The biggest threat to habitats comes from humans and these threats come in many forms, including:
- other industries
- use in the pet trade
- bad reputation of certain animals
- for medicine and magic
- competition with humans
An increasing world population means more food needs to be grown, particularly in third world countries. However, bad land management and a lack of long-term planning is destroying important habitats. For example, one of the quickest ways of clearing land for crops is to set fire to rainforests. These can quickly get out of control however, destroying bigger areas than intended and denying animals and plants food and shelter.
Wetland areas are also being drained to make space for farmland, with rivers and streams being altered for irrigation. This has also been badly managed, damaging greater areas than first planned.
Overfishing in seas has also affected entire ocean-based ecosystems. The biggest threat to whales now comes from the harvesting of krill to make animal feed.
Other industries are also contributing to the destruction of animal and plant habitats. If managed well, rainforests can supply timber and still remain sustainable. However, demand for certain woods, together with the chance of making a quick financial gain, has led to the destruction of vast sections of rainforests, with no signs of them being replaced.
The use of herbicides and pesticides has poisoned large numbers of wildlife and led to essential plants and animals being removed from food chains. What effect the increase in greenhouse gas will have on the atmosphere is unclear at present but experts believe it will lead to even more damage.
Many species are still hunted and killed by humans. Gorilla steaks are popular in some countries, as are shark's fin soup and turtle eggs, putting already endangered species even more at risk.
Animals are also hunted for sport and their body parts seized as trophies by hunters. For example, rhinoceros are usually killed for their horns and elephants for their tusks, with the rest of their bodies left behind.
Although most of the trade in exotic bird feathers or animal fur is now illegal, a substantial black market still exists.
There is a long history of species, especially birds and primates such as monkeys, chimpanzees and gorillas, being captured, usually when they are young, and sold as pets.
In some countries, animals are also captured and used, often illegally, in medical or scientific experiments. Myths about animals exist in many cultures where people believe certain creatures possess magical or medicinal properties.
For example, some populations drink animal blood, eat crushed bones or minced brains or wear teeth or other body parts as protection. They believe such practices will bring them strength, long life, wisdom and virility. Some of the claims may have some basis in reality, for example, taking calcium for strong bones or teeth, but most are simply old wives' tales or folklore from a particular area.
Competition with humans
Humans also persecute animals when there is competition for food or space. When their habitat is reduced or their usual food sources dry up, herbivores often turn to crops and carnivores to livestock herds to find food. They are then labelled as pests by humans.
For example, sea lions and other natural fishers are often shot by fishermen who consider them a threat to their livelihood.
Humans are also responsible for creating competition between different animal species. The most famous example is the dodo, which had no natural predators until the arrival of man.
Humans not only hunted the dodo but also introduced rats, cats, dogs and goats which destroyed the bird's habitat and contributed to its final extinction.