3. Causes of habitat destruction

Importance of habitats.

Habitats – the different types of environment, which provide food, water and shelter for living things. Forests, deserts, mountains, reefs and wetlands – all examples of natural habitats.

Wetland (habitat of waterfowl) – an ecosystem in which the soil is saturated with water part of the year, such as a marsh or bog.

• Each habitat has its own community of plants and animals, which can take thousands of years to develop fully.

• Humans are extremely adaptable to many habitats and have managed to inhabit a large part of the earth’s land surface. They able to use the products of all sorts of habitats to provide the resources they need for survival and for technological progress.

• Habitats are “stores” of genetic resources, some of which are useful to humans. All domesticated plants and animals species have been developed from wild species, and characteristics from wild varieties can be bred into domesticated plants and animals to improve them.

• Remember that habitats are important for their own sake and not just for the sake of humans. Species are closely related to their environments, and each one is an essential part of the living world.

Two types of factors of habitat destruction:

Inevitably, human activities have had an impact on habitats. The use of land and resources is fundamental to human survival.

• External factors: transboundary effect of river contamination, industrial pollution, rocket-nuclear testing areas.

• Internal factors: wide-scale farming, intensive pasture, haymaking, medical-technical fields, logging, poaching, construction, mining, natural disasters.

Two major causes of habitat destruction:

• urban development

• exploitation of land for resources (mining, timber, agriculture).

If the habitat is destroyed species may die out if they cannot adapt to a new habitat.

• The human population has grown at an increasing rate, and the pace of technological change has accelerated. This is reflected in the rate of habitat change and destruction.

• Strictly speaking, there are no truly “natural” habitats left in the world. Alternation caused by, for example, climate change and bioconcentration – the accumulation of polluting substances – have, over the course of time, had an impact on the remotest parts of the world.

• In the past, exploitation of habitats, by humans and other species, occurred at rates, which the earth could tolerate. We do not know what consequences of the changes may be, but the course of evolution is certainly being altered.

• With every species lost, we lose another resource, which could be of use to us. It is vitally important to preserve local people’s knowledge of habitats and their species if we are to understand the changes that are taking place.

Industries can contribute to habitat damage if they:

• Use raw materials from threatened species.

Examples: tropical hardwoods and peat from ancient bogs, which both take so long to replace that they are effectively not renewable.

• Use the products of any endangered species.

Examples: ivory from elephants, many whale products, black coral and some orchid species.

• Develop land that has not been built on before, but which is rich in species.

• Contribute to pollution of the environment in ways that are harmful to the processes that support life.

Deforestation – the destruction of forests by clear-cutting (cutting-off, fire).

• 25% of land area of the Earth is occupied by the forest (including tropical, moderate, boreal).

• 5% of the world’s surface is tropical rainforest, but it contains 40-50% of the world’s species.

The tropical forests are now being cut down at an alarming rate. However, rainforest destruction is a very difficult political issue, precisely because most rainforests are found in less developed countries. Rainforests are a rich and diverse habitat, but their land, timber and other products are also valuable sources of income. This is an area where global interests appear to conflict with local interests.