The Farmers Mart Jun-Jul 2018 - Issue 57 | Page 42

42 ARABLE
JUN/JUL 2018 • farmers-mart.co.uk
BEETLE BANKS – WHY AND HOW TO
BUILD THEM FOR FARMLAND WILDLIFE
Beetle banks are c. 0.4m high earth banks built across the middle or alongside arable fields. They were
invented in England in the early 1980s (a collaboration between GWCT and Southampton University) with the
aim to provide suitable overwinter habitat for predatory insects (such as the Carabidae beetles) and spiders.
Winter insect densities were shown to reach over 1000 individuals/m2 in tussocky beetle banks! Come
spring, these same insects move into the neighbouring crops and reduce pest species significantly.
NOT long after the first beetle
banks were established across a
wider area of the UK in the early
1990s, it became clear that other
farmland wildlife was benefiting as
well, such as grey partridges using
them as nest sites or to forage for
chick food, hares find shelter from
wind-swept wintery days and har-
vest mice find suitable nest sites in
the tussocky grass.
Sounds wonderful, and it is, ex-
cept that beetle banks are narrow
linear features, and as such can
act as a predator trap. This means
that foxes, badgers or raptors that
hunt alongside them, have a good
chance of finding anything from
ground-nesting birds and chicks,
sheltering leverets or bumble bee
nests. This may especially be the
case in areas where no predation
management takes place, which is
the case across most parts of the
UK and especially Europe.
However, there is a simple
non-intrusive solution: By planting
a minimum 15-m wide, suitably
designed wild-bird seed mix or
flower block along at least one
side of the bank, the chance of
a nesting partridge hen being
detected and killed by a fox, is sig-
nificantly reduced. It can, there-
fore, be assumed that the wider
a block, the higher the chance
that nesting or sheltering wildlife
will remain undetected from their
natural predators.
How to establish the
perfect beetle bank
During normal autumn or spring
cultivation, create a 2-3m-wide
and minimum 0.5m high bank
(after establishment the bank
usually settles and hence ‘shrinks’
a bit), by careful two-directional
ploughing. To achieve the desired
dimension, plough the width of
approximately 8m bare ground
into a bank. At Rotherfield, using
a 6-furrow reversible plough, we
worked the equivalent of three
plough-widths to build our banks.
This required eight passes, four on
each side.
Once the