Human Impact – Habitat Destruction

A few centuries ago, when the human population on Earth was smaller and less affluent, mankind required less land and consumed far less of the planet’s resources. Enough contiguous wild habitat existed to ensure that butterflies could move easily between their breeding sites.

Since then the human population has grown and has become increasingly wasteful and greedy. Wild places have consequently diminished in size and become increasingly fragmented and isolated.

Shrinking habitats mean smaller butterfly populations. As breeding sites become smaller and more isolated, gene interchange reduces to insignificant levels.

Butterflies then lose their adaptability and become become dependent on highly localised and specialised habitats. The isolated populations of Papilio machaon in England e.g. can only now survive at a handful of flooded Norfolk fenland sites, whereas in mainland Europe where habitats are larger and less isolated, the species breeds over a very wide area and utilises a broad range of habitat types.

Habitat destruction across the world is caused almost entirely by human activity. Urban expansion has the greatest impact, but governmental policy on farming, forestry and road planning also has a very profound effect on the distribution and abundance of butterflies.

The destruction of the rainforests

In excess of 10000 square miles ( 2.6 million hectares ) of Amazon rainforest is deliberately burnt down every year to clear land for soya and oil palm plantations.

The notion that vegetarianism is beneficial to wildlife is utterly absurd, as wonderful rainforests that support billions of animals and plants are wantonly destroyed, burnt down and replaced with these lifeless and sterile plantations.

In addition to the gargantuan areas of land destroyed to make way for plantations, vast expanses of forest are devastated by slash and burn farming. This normally occurs on a smaller scale as it is carried out by small farming communities rather than by multi-national companies.

Nevertheless it accounts for the loss or severe degradation of many thousands of sq kms of rainforest every year. Land which once supported 750 species of trees, 1500 species of flowering plants, 500+ species of birds and perhaps 1000 species of butterfly, is cleared to make way for cattle ranches. The bounty is short-lived however.

The resulting pastures are poor in nutrients, and only capable of supporting cattle at very low densities. The pastures are burned annually to promote new grass growth and to destroy cattle parasites. The fires rage uncontrolled, devastating vast areas of land.

The deforested land is much hotter and drier than the rainforests – consequently the average temperature of the entire region rises and the humidity falls dramatically. This causes major changes in the vegetation structure of the remaining areas of forest, leading to reduced biodiversity even in protected areas.

Please support rainforest conservation :

sign on-line petitions reduce consumerismreduce your mileageboycott tropical hardwoodsboycott South American beefboycott oil palm productssupport eco-tourismsupport rainforest conservation organisations

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