A1.3.4 Threats to Biodiversity
“The world is losing biodiversity at an ever-increasing rate as a result of human activity. In the UK we have lost over 100 species during the last century, with many more species and habitats in danger of disappearing, especially at the local level.”
Source: DEFRA: http://www.defra.gov.uk/wildlife-countryside/biodiversity/about.htm
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Habitat Loss
As we clear rainforests and woodland for housing, agriculture and industry, whilst concreting over fields for the same purposes, we are destroying the homes of many species.
Some species are able to adapt. For example, foxes move into urban areas and there are even birds of prey in Manchester City Centre. However, some species, such as Orangutan’s cannot.
All animals have basic needs to our own – food, water, shelter. By destroying their natural habitats, we can restrict their access to these basic needs.
Habitat Isolation
Through development we not only destroy habitat, but we fragment what’s left. Two patches of isolated woodland either side of a motorway do not necessarily offer the same habitat as they would if they were joined by a wildlife corridor. Species may not be able to move between the two areas, yet each area may offer something specific that the animals need (water in one and food and good nesting sites in the other).
Genetic Pollution
As species reduce in numbers, the gene pool is also reduced. This can result in specimens with unsound traits reproducing or result in interbreeding; both of which affect will the health of their offspring.
Environmental Pollution
Chemicals and substances released into the environment through human activity, whether emissions to land, air or water all affect the habitats they enter. The substances may be toxic and kill organisms outright (e.g. mercury), or they may change the natural balance making an area inhospitable to life (e.g. excess phosphorus in soil).
