Habitat loss is possibly the greatest threat to the natural world.

Every living thing needs somewhere to live, find food and reproduce. This is known as its habitat. In order for a species to be viable its habitat must have sufficient territory, necessary food and water and a range of necessary physical features. These features can include tree cover, rocky hills or deep pools, as well as the organisms and ecosystems that are needed to complete the life cycle.

Habitat loss is when land cover, or its aquatic equivalent, is changed, usually as a result of changing use by humans. Whenever we humans take over natural areas for our own use, we are encroaching on the habitat of another creature and progressively we are doing this at an alarming rate.

The world's forests, swamps, lakes and other habitats continue to disappear as we make way for agriculture, housing, roads, pipelines and all the other hallmarks of industrial development.

Human activity is responsible for the loss of around half of the forests that once covered the Earth. Although these can recover and can even be sustainably harvested, their rate of loss is about ten times higher than the rate of regrowth.

Europe's wetlands are traditionally an important habitat for countless numbers of creatures, but around 60% have been damaged, even though they are often an essential provider of clean drinking water.

Taking just one example: because of rainforest habitat loss it is estimated that at least 120 out of the 620 living primate species (apes, monkeys, lemurs and others) will be extinct within the next 10 to 20 years.

Habitat loss is generally more serious for the larger animals because they need a greater area in which to have a healthy breeding population. Tigers, mountain gorillas, pandas and Indian lions are good examples, but habitat loss does not just affect animals.

A recent study has indicated that more than 40 species of fish currently found in the Mediterranean could disappear in the next few years. Tropical orchids that thrive in the rain forests are at serious risk as are numerous species of birds from a wide variety of habitats. In fact the only species that are not truly affected by habitat loss are creatures that benefit from human activity such as cockroaches and rats.

The International Union for Conservation of Nature and Natural Resources (IUCN) has a Red List of species officially classified as ''Threatened'' or ''Endangered''. Habitat loss has been identified as being the main threat to 85% of these.

Habitat loss is also a huge problem in the marine environment. Destructive fishing, using deep trawlers and dynamiting coral reefs destroy entire ecosystems. Coastal habitats are destroyed when land is drained for development. Excess nutrients from fertilisers or domestic sewage flow into the sea, causing harmful algae to form, blocking out the sunlight and depleting the water of oxygen.

Pollution from toxic substances such as industrial chemicals, pesticides and motor oil are also a real problem. Dredging ship channels will stir up accumulated sediments and pollutants and the removed material is often dumped on salt marshes, destroying the habitats of the creatures that live there.

Accidents at sea have also had a profound effect on habitat destruction. Several large oil tankers have been involved in major spills, and of course there was the Deepwater Horizon oilrig disaster in the Gulf of Mexico. In each case, enormous quantities of oil have been released into the ocean, devastating the entire ecosystems of the area.

Diversity loss is yet another feature of habitat degradation. A particular ecosystem is home to a number of species and as these begin to go into a rapid decline following the loss of their habitat, a more aggressive species might take the opportunity and move in. As the original species struggle to survive in an increasingly hostile environment, the aggressive invader causes further decline until it eventually reigns supreme.

The proliferation of invasive species poses a strong threat to native species as they struggle to cope with highly fluctuating environments. In order to mitigate diversity loss, it is important for conservation efforts to focus on reducing the numbers of invasive species.

The world is getting warmer and climate change has already had, or is expected to have, a serious influence on habitat loss. Many former habitats have already become inhospitable. Plants that thrive in damp, cool conditions now simply wither and die during prolonged dry periods.

A study in Nature indicated that within the next 50 years a quarter of the world's land animals and plants could become extinct. This is around a million species.

In the UK, as sea levels rise, marshland close to river estuaries would disappear. The loss of inland wet grassland and coastal sea marsh would lead to the loss of breeding habitats of birds such as the redshank. A continued rise in level would mean the loss of feeding areas needed by waders and other shore birds.

Still in the UK, trees such as the oak and the ash would find it difficult to survive frequent prolonged droughts. Wetland areas that are home to rare moths and other creatures would simply dry out. Warm hot summers also encourage algae to flourish on rivers and lakes, at the expense of fish and bird life.

Milder winters will allow the survival of pests and bacteria that cold weather would formerly have eradicated. This will have a serious effect on crops and wildlife. Thin soils will dry out and erode in summer and flash floods will cause more soil to be washed away.

Rapidly changing weather patterns will also disrupt growing patterns. In parts of the world where rainfall is already scarce, as in parts of Africa and China, crop failure and subsequent famine will become a real danger.

Extreme weather events are increasingly occurring as a result of climate change. These events can be enormously destructive and have a disastrous effect on habitat, since they are often associated with high winds or floods.

We are fortunate to be part of a world that is characterised by the diversity of its many species of plant and animal life. Countless numbers of these species are under threat of extinction, mainly through loss of habitat. The chief reasons for this loss are human intervention and climate change.

The world is already warming and although there is little that can be done about it, we can slow the process down by reducing the amounts of greenhouse gas currently being released into the atmosphere and concentrating more on energy saving measures and renewable energy systems

We are all jointly responsible for the world around us. If mankind can be persuaded to be more environmentally aware of the responsibility to safeguard the habitats of these endangered creatures, there is yet some hope for their survival.