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the presence of birds such as the Greater Spotted
Woodpecker which feed on them. However, invertebrates are not confined to rotting wood or
to the soil. Different species are also to be found all over the trees and the many other,
perhaps less noticeable plants, equally characteristic of woodlands.
Of course the trees themselves provide a habitat for a great variety of other living
things. Hundreds of different lichens clothe their bark. Mixed in amongst these are yet
more species of algae, microfungi, mosses and liverworts. Many invertebrates live in this
wonderful epiphytic microhabitat. A small piece of moss taken from a tree trunk and placed
under a microscope is absolutely hopping with activity.
The invertebrates feeding on all the plants in the wood attract our small woodland birds,
such as Nuthatches, Treecreepers and Blue Tits, and these in turn are the reason why
Sparrowhawks can be found there.
Larger animals such as Roe deer also roam through the wood. While we are unlikely to
actually see them, the signs of their presence will be all around, from the territorial
scratchings of the males, made on saplings, to the dung which they deposit as they go.
While this dung may be undesirable waste to us, there is no such thing as waste in nature
and it will be eagerly colonized as soon as it falls. As many as 350 different species of
invertebrates are associated with the dung of hoofed mammals in Britain alone. The rich
resource of invertebrates living in and emerging from the dung provides food for any
number of predators, such as beetles, birds, small mammals and bats.
We are now beginning to get a feel for the enormous biodiversity or variety of life
present in a single habitat such as a woodland, which before we learnt how to look seemed
so empty of life. If we extrapolate this to encompass all the available habitats in the
world, which in itself would be a staggering list, some idea of the unbelievable variety
of life on earth starts to emerge.
In spite of hundreds of years of scientific investigation we still have little idea of the
exact numbers of species contained within habitats. We have even less idea of the many
complex interactions going on between them.
As a result of this ignorance it is essential to conserve whole habitats and their
ecosystems rather than tinkering with individual parts of them.
Habitats are the basic essential for biodiversity to exist. They guarantee life on earth.
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