|
'one
of the most prolific localities in rarities both Entomological
and Botanical, and embracing the most beautiful scenery with
which I am acquainted.'
The
most numerous insect is probably the yellow meadow ant, whose
anthills are often an indicator that an area has been grassland
for many years. There are also several types of bees and wasps,
including wood wasps, and a number of interesting beetles
such as the soldier beetle, the bloody-nosed beetle and the
cardinal beetle. An invisible life is lived in these grasslands
by many other invertebrates, not least the grasshopper and
the large Roman snail, now becoming scarce. Wingless female
glow-worms shine in the grass on summer nights; the males,
which are winged, glow less brightly but sometimes fly into
lighted rooms.
But the show-stoppers are the butterflies: Box Hill provides
a habitat for a staggering 40 of the 58 British species, among
them the common blue, the chalk hill blue, the Essex skipper
and the marbled white. The adonis blue, which due to careful
management has recently made a comeback, enjoys a remarkable
symbiotic relationship with the yellow meadow ants and the
horseshoe vetch: the butterfly lays its eggs on the vetch
on warm south-facing slopes and when the eggs hatch the caterpillar
produces honey dew on which the ants feed. In return, the
ants protect the pupa and the caterpillar, taking it below
ground where it turns into a butterfly - and so the cycle
repeats itself. Centuries of light grazing have produced the
extraordinary species-rich pastures of Box Hill. The North
Downs were cleared by Stone Age people in about 4000 BC, when
crops were planted and settlement patterns developed.
As arable farming became concentrated in the richer soils
of the Weald, sheep grazing became common. From AD 500 onwards,
until the end of the nineteenth century, shepherds grazed
their flocks on the downland slopes by day and 'folded' them
on the lower arable fields at night for enrichment by dung.
In this way nutrient levels on the downland turf were reduced.
And it is precisely because the downland is unimproved - in
other words unfertilised - that it supports such a spectacular
variety of plants (and therefore invertebrates and birds)
without competition from dominant, fertility-loving grasses.
The brightly coloured downland plants are able to co-exist
in such density because each species has adapted to exploit
the environment in a different way. Growing conditions are
tough. Soils are poor and the exposed hills are at the mercy
of the weather. Under pressure from grazing, parched in summer
and frozen in winter, each plant must compete for water, minerals
and light. These constraints prevent plants from reaching
their full potential and a delicate balance is achieved in
which no one species can dominate.
Back
to top...
|