State of Nature report - RSPB

WOODLAND
he indicator for butterflies
in English woodlands shows
that woodland butterflies
are declining (see Figure 13).
Wider countryside butterflies within
woodlands have declined by 43%
since 1990 3 (a UK equivalent
indicator has yet to be calculated).
The loss has been particularly
severe for wood white and Duke
of Burgundy butterflies, amongst
others. Most declining species are
now restricted to actively managed
woodlands and habitats such as
rides, glades and clearings.
All (1256)
Invertebrates (771)
Plants (422)
Vertebrates (63)
Strong decrease
Strong increase
0 25 50 75 100
Percentage of species
Slight decrease
Slight increase
There is also cause for concern about
our woodland birds, which have declined
by 17% overall since 1970 4 (see Figure
14). Woodland specialists have fared
particularly badly, while more adaptable
generalist species have increased.
Since the declining species are found in
a range of different woodland habitats,
it is unlikely that the same change in
woodland management or habitat
is affecting them all. However, six of
the declining species, including the
nightingale and willow tit, all rely on
younger woodland growth stages, so
the reduction in coppicing and other
active management in lowland woods
is likely to have affected them. Most
of the birds that have increased or
remained stable, such as great spotted
woodpeckers, are associated with
mature woodland and may be benefiting
from an increase in woodland coverage
and the reduction in woodland
management during the 20th century.
Our analysis shows that, of the 1,256
species assessed, more are decreasing
(60%) than increasing, and 34% have
decreased strongly (see Figure 15).
Nearly two-thirds of the invertebrate
species we have monitored are declining,
as are 58% of flowering plants. News
for vertebrates is better as they are
evenly spread between the decreasing
and increasing categories. Both of our
Bechstein’s bat is one of the UK’s rarest
bats, and is found almost exclusively in
woodland. It relies heavily on mature
deciduous semi-natural and ancient
woodland, making it very sensitive to
habitat fragmentation and intensive
woodland management.
The first systematic survey of the bat’s
distribution, from 2008 to 2011,
revealed Bechstein’s bats in new woodland sites in Buckinghamshire, Dorset, Kent,
Gloucestershire, Somerset, and Worcestershire. This range extends much further north
than previously thought, and includes the most northerly breeding population known in
Europe 6 . Work is currently underway to help understand the needs of this species and
ensure that woods are managed appropriately.
native deer species, the red and roe,
have increased substantially, leading to
excessive grazing that damages woods.
The increasing number of non-native
deer is making matters worse.
Woodlands provide important habitat
for many threatened mammals. These
include the hazel dormouse, red squirrel,
pine marten and all 17 species of bat
resident in the UK 5 . Woodland features
such as woodpecker holes and loose
bark provide roosting sites for bats.
Of 262 woodland flowering plants
assessed, 30 (11%) are on the
national Red List. Some are considered
Critically Endangered, including green
hound’s-tongue, which prefers open
glades and rides in woodland. These
features are gradually disappearing as
woodland management has decreased.
We know little about how invertebrates
are doing, but it is clear that woodlands
are important for them. Humid leaf litter
and deadwood support a great range of
species, including centipedes, woodlice
and millipedes. Flies make up a huge
proportion of the biodiversity in woods,
both in terms of the number of species
and their relative biomass. Beech woods
are particularly important for rare flies
and beetles, but other special species
occur in Caledonian pine forest, Scottish
aspen woods, old alder woods and
northern birch woods. Many widespread
moths that use woodland are declining.
We know that 236 species have declined
strongly over the last 40 years, and
some rare and localised species
such as the drab looper moth have
declined severely.
Internationally important pasture
woodland and veteran trees can be
found in the UK, which provide habitat
for scarce invertebrates and fungi that
depend on dead and decaying wood.
Several UK woodland types are also
of high international importance
for lichens, particularly those along
the Atlantic fringe, the lowland
wood-pasture and parklands of
the New Forest, and the native
Caledonian pinewoods of Scotland.
36 STATE OF NATURE 2013