Habitats in Britain &
1 - Forests and woodlands
2 - Grasslands and scrub
3 - Heathlands and moors
4 - Coastal habitats
Uncultivated grasslands are among the most important habitats for
butterflies. If suitably managed they become carpeted in wild flowers
such as birds foot trefoil, hairy violet, cowslip, horseshoe vetch,
kidney vetch, common rockrose, devil's bit scabious, sheep's sorrel
and creeping cinquefoil. Each of these plants serves as the larval
foodplant of a particular species of butterfly.
These and many other wild flowers such as
marjoram, thyme, knapweeds, self heal, germander speedwell, buttercup,
dandelions and daisies are also extremely important as nectar sources
for the adults.
Finally of course are the grasses -
fescues, bents, couch, timothy, Yorkshire fog, wood false brome etc;
which are the larval foodplants of various Skippers and Browns.
Chalk grassland at Cerne
Abbas, Dorset, England ©
areas of calcareous ( chalk or limestone ) grassland such as the South
Downs, North Downs, Chilterns, Malvern Hills, Purbeck Hills and
Cotswolds can support enormous butterfly populations, but even small
areas of grassland, in woodland clearings, along railway cuttings, in
meadows and in abandoned chalk quarries are of immense value if
suitably grazed and managed.
Disused railway line running
through chalk grassland and woodland, Dorset ©
Grazing and scrub
ensure the continuing survival of a wide diversity of butterfly
species, it is essential to manage grasslands so that they support a
variety of different vegetation types.
Management has to be tailored according to the situation - some sites,
because of their situation, can only be managed by mowing or flail
cutting, but cattle or sheep grazing generally creates much better
conditions for butterflies.
graze in a manner which produces a uniformly fine sward, with a
profusion of vetches and trefoils, and creates a habitat particularly
suitable for certain blues and skippers.
grazing, in conjunction with scrub control measures, has been shown to
be the best overall management technique however, as the grazing
pattern tends to create a mosaic of different sward heights, with a
more diverse flora that accommodates a wider range of butterfly
The timing of grazing is extremely
important - summer grazing can for example have a detrimental effect
on species which spend summer in the larval stage, feeding on grasses
or herbaceous plants.
Wild rabbits are of immense value as
natural grazers, particularly as their excavations expose patches of
bare soil where butterfly foodplants can germinate. Periodic surges in
rabbit populations however can result in severe over-grazing that can
easily wipe out certain butterfly species. Stock densities of cattle
and sheep therefore need to be carefully tailored to take account of
the effects of rabbit grazing in any particular year.
Another consideration is that each
species of butterfly has different requirements - some need the
grasses to be lush and tall, while others need it to be very short.
The Adonis Blue and
Silver-spotted Skipper for example will only breed at warm sites,
favouring south facing slopes where the grass is short and sparse.
Chalkhill Blues, Small
Coppers and most other grassland butterflies need a slightly taller
sward of about 10cms, where the habitat is moister and rich in wild
flowers. Most of the Satyrinae and Hesperiinae on the other hand
require a sward of between 15 - 30cms.
Getting the balance right, to create a habitat that will support
viable populations of a wide variety of species, can be very
difficult particularly if the site is small. Unfortunately it is
sometimes necessary to prioritise and cater for one particularly
scarce species at the expense of another. On larger sites this is
less of a problem because different parts of the site can be grazed
at different times of year or at different livestock densities, to
cater for a multitude of butterfly and moth species, while at the
same time providing habitat for other forms of wildlife.
Ramsdean Down, Hampshire ©
not only the grasses and wild flowers that need to be managed - a
site left unmanaged would within a few years become overgrown with
bramble, privet, dogwood, buckthorn, gorse, hawthorn and blackthorn
bushes which would shade out the herbaceous plants and grasses.
Eventually the site would revert to woodland, and all the wild
flowers and grassland butterflies would disappear.
therefore need to be periodically cut back - a process known
colloquially as 'scrub-bashing'.
It's very important however to get the balance right, because a
certain amount of bushy vegetation is beneficial to butterflies,
providing much needed shelter from wind and blazing sunlight. Bushes
also provide perching places which males use as lookout posts from
which to survey and intercept potential mates.
Excessive scrub removal can cause major problems for butterflies,
because many species lay their eggs on herbaceous plants that grow
around the base of bushes. If they laid their eggs on plants in open
areas away from bushes, the resulting caterpillars would perish -
either through desiccation in bright sunlight, or because rabbits
would eat the plants on which they depended ( plants growing close
to bushes are normally ignored by rabbits ).
Grassland butterflies thrive best, both in diversity and abundance,
at sites where a well considered grazing and scrub control regime
produces a mosaic habitat in which bare ground, short turf, lush
vegetation and bushes are all essential elements.