ACADEMIC READING
TEST
FOUR
READING PASSAGE 2
You should spend about 20 minutes on
Questions
14-28
which are based on Reading Passage 2 below.
A
I have recently planted a hedge. Living in a rural
environment, I made the decision to plant only
native species,
including field maple, hawthorn,
hazel, dog-rose and blackthorn. In time this will
grow to form a dense hedge whose primary
purpose is to form a windbreak, but which will
also be attractive both to me and to wildlife. In
the two years since planting,
a
number of
hedgerow wild flowers, such as scabious and
knapweed have already begun to colonize the
spaces between the growing shrubs. Of course, if
allowed to grow too freely, rank weeds and
grasses will limit the growth of the hedge and
need to be removed. This is done by hand,
without the use of herbicides, in order to
encourage bio-diversity.
B
But it is not only native species that have found a
foothold in the new growing environment. A
number of garden plants of non-native origin
have also established themselves. Some have
come via wind-blown seeds,
some through bird
droppings, while others have arrived through
human agency, stuck to the soles of boots or as
dormant seeds embedded in garden compost.
They include
Lychnis coronaria, Echinops ritro and
Brunnera macrophylla, all valued garden plants,
but looking rather out of place in a natural setting.
Such intruders are called 'garden escapes', and it
isn't only my garden they are escaping from.
C
In his recently published book,
Flora Britannica
(1
Richard
devotes a whole chapter
to garden escapes. Many of these are relatively
recent introductions, such as
the Indian balsam
which was first brought to Britain from the
Himalayas in 1829, and
Fuchsia magellanica which
arrived about the same time. Both of these grow
wild in Britain now; Indian balsam may be found
along riversides and in damp places all over
Britain, while
Fuchsia magellanica is mostly
confined to mild south-west England.
Buddleja
davidiiwas introduced from its native China in the
1890s and is now a ubiquitous shrubby weed of
urban wasteland, derelict building sites or
crumbling walls. Its dusky purple flowers are
much frequented by butterflies and for this reason
it is by no means an unwelcome interloper. Like
the others i t has succeeded by exploiting an
ecological niche. No native British plant species
has been able to colonize dry inhospitable urban
landscapes to such advantage.
D
Other vigorous aliens introduced as garden plants
are now regarded as pernicious weeds. One such
is Japanese knotweed, probably introduced into
Victorian gardens in the 1840s. Its root system
extends rapidly and it is able to regenerate from
the smallest fragment of root. It forms dense
thickets reaching 1.5
metres in height, under
which no other plants can grow and little animal
and insect life can be supported. It spread from
London in the early 1900s and by the early 1960s
was reported in every county of mainland Britain,
reaching us even here in the remote Suffolk
countryside. It is virtually ineradicable, and is now
a serious pest in parts of south-west England.
Another unwelcome intruder is giant
an undeniably handsome herbacious perennial,
reaching up to four metres in height in damp
meadows or open woodland, crowned with
enormous umbels of white flowers. It, too, is
invasive and i t s sap i s
also poisonous causing
severe skin irritation and blistering, especially
when activated by the ultra-violet rays of bright
sunlight. Children are particularly at risk as the
thick hollow stems and broad fan-like leaves lend
themselves to a variety of games.
E
This process is taking place all over the world.
Plant species from one continent are introduced
into the gardens of another, or as a food crop, or
for hedging. They may then spread disastrously,
taking advantage of suitable climatic and soil
conditions, and of the fact that there may be no
animal, insect or fungal predators in the new
environment to keep them in check. The prickly
pear, a spiny cactus originating in Central
America, was introduced into Australia to control
stock and keep out wild animals. It has now
colonized vast areas of the Australian outback as
both domestic animals and wild kangaroos and
other herbivores find it virtually inedible. Prickly
pear also grows now in parts of southern Arabia
and is spreading rapidly. Even goats, which will
eat almost anything of vegetable origin including
cardboard boxes, find
it
difficult to deal with the
dense spines of this cactus.
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