Farmland
Biodiversity
Measures to create and enhance
farmed habitats
Farmland Biodiversity
Measures to create and enhance
farmed habitats
Caitríona Carlin and Mike Gormally
Applied Ecology Unit, NUI Galway
and
Daire Ó’hUallacháin and John Finn
Environment Research Centre,
Johnstown Castle, Teagasc
2010
Table of Contents
Page
Introduction
How to use this guide
4
Part 1
5
Part 2
Part 3
How to manage commonly occurring
habitats on the farm
Hedgerows, stone walls and earth
banks
6
Wet ditches and drains
9
How to create new habitats on the farm
11
Creating ponds, puddles and scrapes
12
Creating woody habitats in orchards
Creating log piles
14
15
How to maintain special habitats on the
farm
16
Dry grasslands
17
Wet grasslands
19
Semi-improved grasslands
21
Blanket bogs
23
Turloughs
25
Fens
27
Acknowledgements
29
Sources of additional information
30
Selected bibliography
31
GC
CS
MSS
4
Introduction
What is this guide?
This guide aims to (1) raise awareness of ecological features on farmland,
(2) explain why they are important and (3) demonstrates how they could
be managed to help wildlife. This guide is not a detailed habitat
management manual. Additional sources of information such as selected
bibliography and weblinks are provided. Please consult with National Parks
and Wildlife Service when considering work on specially protected sites.
Who is it for?
This guide is aimed at farmers and all people involved in providing advice
on managing land.
Why is this guide needed?
Some of Ireland’s best-known wildlife require farmland. Bumblebees, bats
and barn owls rely on farm practices to provide them with shelter and
food. Plants and animals have been able to exploit different parts of the
farmed countryside, such as dry stone walls and earth banks, hedgerows,
trees, woodland belts and copses, wet ditches and ponds. Many species
need a mosaic of different habitats: for example, some beetles like to
overwinter in grass tussocks, but bare ground can also be important for
basking.
A number of scientific papers have been published which describe the
ecology of different habitats and how the species found within them are
influenced by management, including farming practices. Some of this
information, which has been generally unavailable to farmers, is presented
in this guide.
How to use this guide?
This guide will help to identify important wildlife features on a farm.
It is divided into 3 key sections, each with relevant images.
Part 1: How to manage commonly occurring habitats on the farm
Part 2: How to create new habitats on the farm
Part 3: How to maintain special habitats on the farm
This guide is compact and designed to be taken out and used around the
farm. It aids visual recognition of key features that are good for wildlife
and suggests a variety of steps to benefit farmland habitats.
Part 1
Commonly occurring habitats on the farm
6
Field Boundaries
Dry stone wall
Hedgerow
CS
Hedgerows and tree-lines
are
features
in
the
landscape.
Tree-lines
mainly comprise mature
trees whereas hedgerows
mostly consist of shrubs.
Timber should not be
extracted from the treeline. Dead and decaying
wood should be left in
situ. Retain a margin to
ensure spray drift and
fertiliser does not reach
the hedge.
Woodland belt
DB
Stone walls are man-made
DB
structures which vary in
their
age,
geology,
construction
style
and
thickness.
Walls
can
support a wide variety of
wildlife such as lichens,
mosses and ferns. Some
invertebrates and lizards
bask on south facing walls,
whereas hedgehogs and
smooth
newts
may
hibernate
within
thick
stone walls.
Woodland belts can be
small islands of seminatural habitats within
the farmed landscape.
Native trees should be
dominant,
with
an
abundant understorey.
Timber should not be
extracted
from
the
woodland. All dead and
decaying wood should
be left in situ. Allow
scrub to develop around
the margins.
Hedgerows and tree-lines
Hedgerows were planted as boundary features. Typically
they consist of shrubby trees such as Hawthorn, Hazel,
Guelder Rose, Dog Rose, Blackthorn, Holly and Bramble.
7
Hedgerow
plants
Plant a variety
of
shrubs
to
provide food or
shelter
to
wildlife
during
the year.
Honeysuckle
•Leave uncut during the winter to provide berries for birds.
Cut between January and February. No cutting can take
place between March 1st- August 31st.
•Cut about one-fifth of the hedge at least once in a three
year cycle.
•Typically hedges that are higher, wider and bushier at the
base are better for wildlife. Sidetrim the hedgerow to about
1.5m high, forming an A shaped profile which helps thicken
the hedge.
•Retain a margin adjacent the hedgerow.
Hawthorn
Guelder Rose
Dog Rose
Hedgerows require management. This hedgerow has
become overgrown because it has not been managed. The
hedgerow has “escaped” and is becoming a tree-line.
Reinstate gappy hedges by planting up the gaps or lay the
old hedge.
Stone walls and earth banks
Common Blue
Damselfly
Common
Grasshopper
Spleenwort in wall
crevice
Earth banks
Wild Strawberry
8
Features to maintain
•Retain stone walls
where present. Repair
stone walls where
necessary.
•Maintain local
techniques and styles of
wall construction.
•Walls may support
lichens, ferns and
mosses. Don’t remove
vegetation.
•Take care when
spreading slurry to
ensure that no slurry
drift reaches the wall.
•Remove Ivy if the wall
becomes unsteady.
•Do not paint dry-stone
walls.
Features to manage
Earth banks are wide
grassy margins which
contain a variety of
plants, and may contain
scrubby trees, shrubs
and occasional stones.
Grassy bank with
Birdsfoot Trefoil
•Do not apply herbicide
or pesticide.
•Do not deposit waste
on the earth bank and
remove any dumped
rubbish.
•Cut once a year in the
late summer to allow
grasses and flowers to
set seed.
•Take care to avoid the
accidental spillage of
slurry or manure.
9
Wet ditches and drains
Features to note
Wet ditches and drains were once dug to drain waterlogged soils and assist with
the intensification of farming practices. However, ditches nowadays frequently
receive little maintenance and often retain species characteristic of wetland
habitats.
Key features are shallow edges with some bare mud, sloping banks and a
varied depth. The extent of vegetation present should vary, from very little to
abundant.
Features to manage
•If drains become silted up, a dredging programme may need to be instigated
on a four year rotation.
•Identify an area of low biodiversity value for spoil deposits before dredging
begins.
•Undertake dredging in the autumn to minimise impacts on amphibians and
invertebrates.
•Do not clear the whole drain at the same time.
Damselfly beside Starwort
Water Snail feeding
Marsh Marigold
Wet ditches and drains (continued)
10
Features to maintain
•Maintain species richness by mowing or cutting opposite sections in a threefour year rotation. This removes fast growing species and allow slower growing
species to mature.
•A cut twice a year retains more plant species than mowing once, never, or
every alternate year.
•Leave cut vegetation on the bank overnight to allow invertebrates and
amphibians return to the drain.
•Best practice maintenance is to work from one side of the bank only, in small
sections, leaving at least some sections unmanaged in each phase of rotation.
•A spring cut may benefit vegetation but late cuts at the end of the summer or
during the autumn are often recommended for birds e.g. Reed Bunting.
Features to enhance
•If drains begin to dry out, drains may be allowed to silt up or sluices may be
erected
to retain
ditch habitats.
Features
to enhance
•Fencing may be required, but fence installation should allow for occasional
controlled access by cattle to graze bankside vegetation, and open up bare
ground through a small amount of poaching.
•During the Autumn, depth can be varied by removing a small section of the
bank to create a shallow shelf along the edge of the drain. This shelf, called a
berm, alters the slope and increases the surface area of the bank, allows for
fluctuating water levels and creates sheltered habitats for amphibians and
invertebrates. Cattle access may naturally create a berm, or machinery may be
used to build it.
Water Mint
Large Red Damselfly
Water Avens
Part 2
Creating new habitats on the farm
KS
Farm ponds, puddles and scrapes
12
Ponds are usually small bodies of standing water, surrounded by and containing
vegetation, muddy bays of bare ground, many invertebrates and are used by a
wide variety of birds, amphibians and mammals.
Features to note
•an irregular
shape
•shallow depth
•deep in one
section only
•partly in shade,
partly in sun
•Small muddy
scrapes located
nearby
Ponds with high biodiversity value are often sited in natural hollows, close to
remnants of other habitats such as treelines, earthen banks, hedgerows,
orchards. Ponds close to one another form a network of ponds in the
landscape. Different sizes increase the variety of wildlife.
Choosing the location of a pond
•Pond water quality is important in deciding where to locate a network of ponds
in the landscape. Do not locate ponds where they will be subject to runoff from
intensive farmland. Ponds should be fed by clean water, that is, water that runs
off deciduous woodland, old pastures and other semi-natural or conservation
habitats.
•Do not dig out or deepen existing wet areas as they often have their own
wildlife value. This includes marshes, reedswamps, reedbeds, muddy scrapes
and wet grassland.
Mayfly
Frog in breeding
condition: male has
a blue chin.
Damselfly near Gypsywort
Farm ponds, puddles and scrapes (continued)
Diving Beetle
Smooth Newt
13
Pond Skater
Features to manage and maintain
This is general guidance only. More advice and detailed instructions are
provided by Pond Conservation Trust (see further information).
Timing factors
•When to dig the pond depends on the location and impacts on other wildlife.
•The best time to create ponds is in autumn.
•Avoid creating ponds in very wet weather. Heavy machinery can damage the
soil structure.
•The best shape is a slightly irregular kidney bean shape as this creates small
sheltered bays.
•Whether a liner is used or not, ensure there is a substrate to which plants can
attach.
•Over time, plants will colonise the pond, but the process can be speeded up by
carefully selecting a few native plants from a nearby pond. It is unlikely that
plants from garden centres are native and therefore must be avoided.
•Plant trees to the north of the pond, some way back to ensure leaves cannot
clog up the pond.
• Clean out each pond in a phased three-four year rotation. If too much silt is a
problem, remove silt between September – November. Clear unwanted leaf
litter at the same time. Plant thinning can be done in the first 6 months of the
year. In summer, remove excessive duckweed. Dispose of unwanted material
away from the pond.
Features to enhance
•If space allows, create a number of ponds at different times to maintain pond
vegetation at different age structures.
•If a pond is large enough, some access could be given to cattle to allow a little
poaching and disturbance, but this would only be for limited periods of time to
prevent the pond becoming turbid.
•Locate ponds close to field boundaries such as tree-lines, hedgerows, field
banks, and woodland to avoid farm traffic. Maintain a buffer zone around the
pond to protect the habitats within 50m of the pond.
•Excavate shallow scrapes with slowly receding water levels close to an existing
pond to benefit invertebrates and birds.
Woody habitats and orchards
14
Features to note
Old orchards have the potential to become
biodiversity hotspots, comprising a range of
habitats such as dead or decaying wood, species
rich grassland and hedgerows and stone walls.
Stone wall
Decaying wood
Apple blossom
Orchard trees support lichens, mosses, fungi and beetles and provide food for
many birds, mammals and pollinators.
Features to manage
•A diverse ground flora can be maintained within orchards by traditional
grazing or mowing practices.
Green Veined White Butterfly on Dandelion seedhead with other ground flora
such as Wood Violets, Barren Strawberry and Bluebells.
Features to enhance
•Plant new fruit trees to ensure the future of
orchard habitats.
•Plant a flower-rich border adjacent to the orchard
to attract bees; use native wildflowers if possible.
•Retain standing dead wood. Splits and holes
provide shelter for bats and birds.
Standing wood
Log piles and other woody habitats
15
Features to note
•Log piles can support moss, lichens and other flora and are used as an
overwintering site by amphibians, Hedgehogs and some invertebrates.
A south facing slope provides
basking areas for Common Lizards,
so keep brambles cut back.
Log piles in shady spots are useful
for many invertebrate species.
Features to create
•Stack cut timber to form log piles in a variety of frost-free locations, facing
south, west and east to maximise basking opportunities for invertebrates and
Common Lizards.
•Create dedicated spaces for invertebrates by filling wood pallets with hay,
straw, rough cut wood logs, and dried umbellifer stalks.
•Drill holes into some of the logs to create additional over-wintering spaces.
•Place log piles beside ponds to provide suitable hibernation sites for
amphibians and invertebrates.
Features to enhance
•Include living
plants like Ivy,
Clematis and
Honeysuckle
in a logpile, as
well as dead
stalks and dry
seed heads to
attract bees or
butterflies and
mammals.
KS
•Leave decaying wood in situ. To enhance wet wood wildlife, place decaying
wood in and close to nearby ponds.
•Fungi and wood eating invertebrates will colonise rotting wood. Place rotting
timber in shade to form a decaying wood microhabitat.
Part 3
Special habitats on the farm