State of Nature report - RSPB

Why is urban wildlife changing?
A
s the human population has
increased, the amount of
green space in urban areas
has declined, along with the wildlife
that relies on it.
Loss of even low-value habitat can
have a huge impact on wildlife, as it
often acts to connect larger patches
of important habitat. Without these
connections, even good quality green
space can fail to support healthy
populations of many species such
as hedgehogs, bats and slow-worms.
Urban wildlife often finds refuge
in small and vulnerable habitats.
For example, old walls can support
important plant communities and
colonies of bees and wasps, such
as the hairy-footed flower-bee,
wool carder-bee and red mason-bee,
but they are vulnerable to demolition
or unsympathetic restoration.
Changes in the way humans live
– our housing designs, building
standards and gardening fashions –
can have unintended but sometimes
sweeping impacts on the nature
around us, and the needs of wildlife
are often low down on the list of
urban priorities.
Example
Many species, such as hedgehogs
and bats, rely on wildlife corridors
to move around their territory
and find food and shelter. Small
isolated populations are vulnerable
to chance extinction events, such
as a run of very cold winters or a
new disease.
Example
An estimated 10,000 playing fields
were sold for development from
1979 to 1997 6 , and the area covered
by allotments, which provide a
haven for wildlife, has dropped to
just 10% of its post-war peak 7 .
Loss of green spaces
Example
Many gardeners are now less
tolerant of “weeds” and use more
pesticides. More space is covered
by decking, gravel and other
sterile surfaces: 5,900 hectares
of front gardens in London have
been hard-surfaced 8 .
Fragmentation of habitat
Tidier gardening
Example
Example
Many bat roosts
are destroyed
during
refurbishment,
despite the
legal protection
afforded to them.
Space for wildlife,
such as bats and
birds, needs to
be specifically
designed into
plans for new
buildings and
conversions.
Changes to
buildings
What factors affect
urban wildlife?
Climate
change
The effects of
climate change
are enhanced
by the higher
temperatures
found in most
cities and larger
towns. This
phenomenon,
known as the
urban heat island
effect, means
that most UK
cities are 1 or
2 o C warmer than
the surrounding
countryside.
Non-native species
Water and air pollution
Example
An estimated 55,000 non-native
plant species are grown in UK
gardens 9 , many of which could
join the 1,300 or so non-native
plants that have been recorded
growing wild in the UK 10 : A small
number may come to dominate
some ecosystems in the way
that Japanese knotweed and
Himalayan balsam are doing.
Example
Unsurprisingly, there are higher
levels of water and air pollution
in towns and cities than in other
habitats, and this can seriously
affect wildlife. However, the
good news is that water and air
quality have both improved in
recent decades.
STATE OF NATURE 2013 55