Biodiversity & Environmental

Studies

Describing all the different forms and kinds of life in a specific area.

Studying the effect that changing nature has on the level of biodiversity in an area.

Natural and Man-made effects can change the level of biodiversity.

Natural effects will balance out over time.Man-made effects more often than not lead to extinction and limiting of biodiversity.

It describes two distinct but related phenomena observed since the late 1970s – 1)a steady decline of about 4% per decade in the total volume of ozone in Earth's stratosphere (the ozone layer), and 2)a much larger springtime decrease in stratospheric ozone over Earth's polar regions (ozone hole).

The primary cause of ozone depletion is the presence of chlorine-containing source gases (primarily CFCs and related halocarbons).

In the presence of UV light, these gases dissociate (move apart), releasing chlorine atoms, which then go on to catalyze ozone destruction (breaking).

A process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions.

This causes the maintenance of planetary temperatures.

If greenhouse gases increase, the planetary temperature also increases.

Clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use.

Examples include road construction, farming etc.

1992

2006

Trees are necessary for:1)O2 production2)CO2 sink

The process by which fertile land becomes desert.

This naturally happens due to drought.

Man also causes desertification through deforestation and inappropriate agricultural practices.

Rainfall which has been made sufficiently acidic due to atmospheric pollution.

Damage occurs not at the source of pollution, but at the point where rain falls.

Excessive richness of nutrients in a lake or other body of water.

Caused by runoff from the land, mainly agricultural land which has richly been fertilized.

Reducing the population of a wild animal by selective slaughter.

This is done to get the numbers of the population back down to sustainable levels.

Usually enforced when the habitat’s carrying capacity is exceeded.

Overgrazing: damaging a grassland so much through grazing that the vegetation is damaged and the ground becomes liable to erosion

Crops: Monoculture leads to decrease in biodiversity because only one type of plant growth is promoted.

Commercial Forestry: Trees planted in blocks that are all roughly same developmental age and have been planted in fixed spacing.

In South Africa the species are mostly exotic (invader species), thus having few natural enemies and usually being more nutrient ‘hungry’ than local species.

The human population reached 7 billion individuals this year.

As the population number increases it requires an increase in food, housing, clothing, education, medical care, transportation etc.

This has an effect on nature, either directly or indirectly.

These are poisons that are aimed at Insects specifically.

They either kill pests to humans or pests to the food sources of humans.

Problems exist when bio-accumulation effects come into play in nature.

Insects can develop resistance to poisons which leads to development of new substances.

dichlorodiphenyltrichloroethane

These are plants or animals that do not originate in the country where they are now found.

Often there is no natural enemy and the invasive specie can reproduce and spread as much as they want.

The ability to use the natural resources AND make them last.

Natural resources are finite, thus if we want them to be available in the future, we need to manage them and their use properly.

1) Environmental lobbying

2) Land rehabilitation

3) Emission reduction

4) Management and treatment of waste