Improving the environment for living things
About two hundred years ago, a great change took place in the way that we make things. Up until that time everything was made by hand. Then it was discovered that things could be made by machines. This change was called the Industrial Revolution. The machines were powered by steam engines and the steam engines needed coal to provide them with energy. Coal is found underground beneath the countryside. This meant that the countryside had to be destroyed when a mine was set up. Things could be made more cheaply if a large number of machines were set up together in a factory. Land was needed to build the factory so more countryside was destroyed to provide factory space. People were needed to run the machines. They also needed to live close to the factory so they did not have far to travel and could work long hours. Houses were set up round the factories. In many places they were built from local stone that was dug out of a quarry. Later, when concrete became widely used, gravel was dug out of the pits to mix with sand and cement. Quarries and gravel pits also destroyed large areas of the countryside.

Today many of the factories are closed. The things they made are now made more cheaply in other countries or new, more efficient machinery can make the things, using less factory space. Most of the mines are closed because it is cheaper to use other fuels such as oil or gas now. When gravel pits were emptied holes in the ground were left behind. Each one of these derelict places is a habitat. They are known as wastelands. A small number of plants and animals live in them.

If you look at a wasteland you see a lot of exposed rock and concrete. The soil is found in patches between them. And it may be teeming with plant life. Many of the plants are the weeds that are found in gardens but they form a supply of food for some insects and other mini beasts. There are no trees or bushes and the only birds that are seen are scavengers such as magpies and starlings. There are few places for mammals to hide and feed. If rubbish has been tipped on the waste ground, rats visit it to feed and even set up home. The main water features in a wasteland habitat are puddles. They dry up quickly and do not give water life any time to set up home there. If a wasteland is left alone, the habitat gradually improves as bushes and even small trees grow but the changes take place only very slowly. In many places scientists are improving wasteland habitats very quickly and setting up a range of habitats in them.

Hollows are dug out to make ponds or lakes. The soil from out of the hollows is used to make small hills and banks. These are covered in grass and planted with trees and bushes. Reed beds are set up on the edge of ponds and lakes and islands may be set up in their centres. Paths are laid through the wasteland to allow people to visit but also to keep them away from some areas where more secretive animals, like deer, may set up home.

The ponds and lakes may be stocked with fish but other animals, such as hedgehogs and rabbits, find their own way to the wasteland. In time birds such as the robin and wren take up residence in the trees and bushes, moorhen and ducks breed on the ponds and lakes and kestrels hunt for voles in the long grass. The wasteland habitat has been changed back to the countryside habitats that existed there over two hundred years ago.

Can people go and look at wasteland habitats?
Wasteland habitats are fenced off to keep people out. This is done for safety reasons, as there may be old mine shafts, large amounts of broken glass and rusty rubbish. You must not go onto wasteland which is fenced off. Sometimes there are smaller patches of wasteland in a town. They may be just a few metres long by the side of a road. Even in a park there may be a piece of wasteland that is waiting to be redeveloped. In these small patches of wasteland you can see typical wasteland plants such as shepherd's purse, knotgrass and groundsel.

What kind of animal is a scavenger?
It is an animal which feeds on a wide range of foods. For example, a starling feeds on roots, fruits seeds, earthworms, insects, spiders, snails and slugs. As it has such a wide range of foods it is found on a wasteland because it has a chance of finding something that it can eat. Some scavengers, like the blackheaded gull, will look for scraps of food among the rubbish left on wasteland.

How do animals find their way naturally to the new habitats on an old wasteland?
Many animals travel long distances to find new habitats. At night, even in a town, foxes, hedgehogs and even rabbits can be on the move. Frogs can travel great distances slowly. They move from one shelter to another in damp weather until they find a habitat in which they feel they can stay. It is easy for birds and insects ? they just fly in.

What happens when large numbers of plants and animals build up in the new habitats?
If you think about a natural habitat such as a pond or a wood, it stays the same for many years even though all the plants and animals are breeding. The reason for this is due to the way all the living things are linked together through feeding. Each plant and animal produces a large number of offspring because most of them will become the food of something else. If a kind of plant were to begin to increase greatly in number the animals that feed upon it would also increase greatly in number. They would reduce the numbers of the plant. In a similar way the predators of the plant-eating animal would increase in number too. If the numbers of the plant-eating animal fell, some of the predators would starve to death or move away to find other food. In this way the numbers of plants and animals in a habitat are controlled. It is done naturally and is sometimes called the balance of nature.