This means that many of the
species which live on heathland are under threat. When you visit a heathland you might
think that there is little wildlife present, as you gaze over the open expanse of heather
and gorse, intermingled with grasses, bracken and scattered trees such as Silver Birch.
However it is actually seething with life. At least 5,000 different species of
invertebrate actually live on heathland. These invertebrates include wonderfully marked
butterflies such as the Silver-studded Blue butterfly. You might also see Golden Ringed
dragonflies acrobatically darting about as they catch insects on the wing. On the ground,
bright green Tiger beetles rush about hunting even smaller insects. Birds such as the
Dartford Warbler and the Nightjar also live on heaths, together with reptiles such as the
adder and lizard. If you go out to a Lowland Heath in midsummer at dusk you might even
hear the sound of the male nightjar and witness its
territorial displays. As you look around you
might also see rounded hillocks of earth which are now overgrown with vegetation. These
are ancient burial mounds dating back to as long ago as the Bronze age. Even before this,
neolithic (stone age) people lived on heaths. Indeed it is thought that they created some
of the first heaths, through clearing the original woodlands and then grazing their stock
in the newly created open areas. Grazing stock, such as sheep and cattle, in these areas,
favoured plants like heather because the animals didn't
actually like to eat them! This meant that the animals would eat the grasses and young
tree seedlings instead. Where the soils were poor, sandy and acid in nutrients, this also
favoured heath-type plants and gradually the landscape which we now term Lowland Heath
came about.
Of course, in modern Britain, you don't see so many animals
grazing on heaths. This means that many of the few heaths that remain are being taken over
by trees such as Silver Birch. Silver Birch trees are known as a pioneer species, because
they are often the first trees to become established in an area.
This invasion by trees continues year after year and the
habitat is altered. Eventually slow growing large trees such as oak dominate. The
area gradually becomes a dense woodland and all the plants and animals which can only live
on a heathland are lost. This process of change is known as sucession. The surroundings
have been changed in such a way that conditions favour different plants and animals.
Today, heaths need management in order to prevent trees and
other unwanted vegetation becoming dominant. Management may include the introduction of
grazing animals. Where there are too many trees these will have to be reduced in number.
This type of work is essential if more of this endangered habitat is not to be lost.
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