Saturday, 7 February 2009

Britain's Rare Animals and Plants - How they came here

In this blog yesterday I said

"If the whole of Britain sank under the sea the world as a whole would only have lost a few species.

"There are comparatively few species under threat of global extinction in Britain.

In today's entry I will think about the British vegetation and fauna - why it is so limited, how it has come to be here at all - and alert you to some threatened species.


What - Few British Species under threat of global extinction?

A good number of plants, insects, etc are threatened nationally, and within each county, over the past 100 years, on average one native species of wildflower becomes extinct every two years. (I'll write about that later, with examples of species lost in West Yorkshire)

78 UK higher plant species are now designated as threatened with extinction within Britain.

Only a few species in the UK are under threat of world extinction - and of these we should take especial care.

I'll have to look some of these up!! -

Oh I have just learned about the Lundy Cabbage. The Lundy Cabbage Coincya wrightii only grows on the cliffs on the East side of Lundy Island It is endemic to Lundy. (Endemic means Native to or confined to a certain region). - And it has two endemic beetles living on it!..

Actually that reminds me that near to us in Settle, the Rock Whitebeam Sorbus rupicola which grows in the Malham Cove area is another endemic.. It is slightly different to the Lancastrian Whitebeam which grows across the border in Lancashire Sorbus lancastriensis: the Sorbus rupicola grows near Malham Cove so that my guess is that the whitebeam on the vertical part of the Cove face is also Rock Whitebeam,

but without ropes, I cannot prove it...



Why does Britain have such a relatively poor flora and fauna?

Look at the numbers of native wild flowers found in these three countries:

Native wild flowers in UK:1550 (1,756); France: 4,500; South Africa 23,000.,

Doesn't make you very proud to be British, does it!
Source: Earthtrends website using data from World Conservation Monitoring Centre, Cambridge.

It is all to do with the ice.

Britain was covered by ice in the last Ice Age, 18,000 years ago, Plants and animal could not survive then.. Land not covered in ice in the south of England had very cold conditions.

Since then, temperate animals and plants have come back into Britain in the last 12,000 years from the continent. If we lose some of these species - and it would be sad if we did - most still exist in other countries. -

One such example of a very rare plant is the Large Yellow Sedge Carex flava. It only grows in two places in the UK, one of them being at Malham Tarn, seven miles from our church. It is a highlight of the Sedges courses I sometimes run. But it does also grow in Scandinavia.


More interesting facts: How did the animals and plants get back to Britain after the ice age.?

Many walked across the Land Bridge from the continent. During the Ice age 20,000 years ago the sea level dropped 120m (400ft) below its present level because water was locked up in ice, and also the sea was colder and so had contracted. There was a land bridge stretching across from eastern England to Denmark and the Netherlands . - Fisher men have found flints, remains of conifer forests and on

Why has the land bridge gone?
- after all it is only say 9000(?) years ago - 360 generations ago since it went. (The land bridge to Ireland was lost 12,000 years ago).. The ice melted, the cold water expanded. Also the ice on the North west of UK, especially Scotland weighed Scotland down so the south east of England stuck up like a seesaw - Now the Scottish ice is gone Scotland and Western Ireland are Rising, the south east of England is sinking. If the sea level has risen this much already - think what global warming will do..)

1 comment:

dayana said...

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Margaret

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