Managing woodland for butterflies and moths

 
Managing woodland for butterflies and moths
Managing woodland for
              butterflies and moths

              Why manage woodland at all? Surely a natural woodland, without
              (or with minimum) intervention would best supply sustainable
              habitat for butterflies and moths?

              The answer lies in the processes            cleared woodland habitats. The           For many species, the speed and
              that have formed our present                natural processes that produce such      extent of this change has made it
              landscape. Almost no woodland               habitats within woodland (such as        very difficult to adapt and landscape
              in Britain today can be considered          fires, storms and the natural collapse   changes have reduced opportunities
              wholly natural. We have inherited a         of aging trees) typically occur too      to relocate to suitable habitat
              long history of forestry use that has       infrequently to provide the continuous   elsewhere.
              substantially modified even our most        cycle of clearings needed by these
              ancient woodlands. We have, and             species. Woodlands would also have       Overall objectives
              still are, continuously changing the        been subject to regular, extensive       This guide outlines specific woodland
              composition and structure of woods          grazing and browsing by large            management options designed to
              to meet our needs. The woodland             herbivores which are now absent,         benefit butterflies and moths. These
              wildlife we see today is a product of       and these effects are not replicated     options are designed to achieve the
              that history and many Lepidoptera           by the increasing number of deer         following overall objectives:
              survive in woodland habitats only           now browsing our woods. The small
              because of repeated human use of            size and fragmentation of most           • Structural complexity
              woodland resources.                         woods in the UK also prevent natural     • Habitat diversity
                                                          processes operating at a sufficient
                                                          scale to conserve the full range of      • Foodplant diversity
David Green

                                                          woodland wildlife. Low-intervention      • Management continuity
                                                          management strategies can make           • Landscape connectivity
                                                          a contribution to the mosaic of
                                                          habitats within a landscape, but need    The single most important factor
                                                          to be complementary to an active         that makes a woodland good for
                                                          management process that maintains        butterflies and moths is a diverse,
                                                          and enhances the valuable habitat        uneven structure. This should
                                                          features found in our woods.             include some mature or tall trees,
                                                          Our current suite of woodland            some dense regrowth, numerous
                                                          species coexisted in the past            sunny rides and glades (both large
                                                          alongside often extensive active         and small) and patches of recently
                                                          management of woodlands. So              cleared and regenerating open areas
                                                          why is woodland management now           with sparse ground vegetation and
                                                          considered a conservation issue? The     warm unshaded conditions. This
              Sustainable removal of timber and           reason lies in the extreme speed and     diverse woodland structure creates a
              firewood is an important part of woodland   the huge scale of recent changes.        variety of habitats necessary for the
              management                                  The usage of woodland has always         various life stages of Lepidoptera,
                                                          changed over time, but change has        including larval foodplants growing
              In Britain, applying a non-                 happened very rapidly in the last        in appropriate conditions, a limiting
              intervention approach using only            hundred years. This has occurred not     factor for many species.
              natural processes within most of            just within one type of woodland or      Such a varied structure, with a diverse
              our woodlands will not create the           one region of Britain, but across the    range of tree and plant species,
              habitats needed by many of our              whole landscape. At the same time        not only provides good habitats for
              butterflies and moths. For example,         urbanisation and intensive agriculture   Lepidoptera, but also for a wealth
              many of our rarest butterflies are          has removed or highly fragmented         of other insects and forest wildlife.
              highly dependent on open, newly             much of our woodland network.

              14 | Woodland management for butterflies and moths
Managing woodland for butterflies and moths
Specific requirements for specialist       Managing across                                   patch is likely to undergo regular
species requiring deadwood, lichens,                                                         local extinctions and regular re-
mosses or wetland features can be
                                           the landscape                                     colonisations. Problems arise when
integrated with this overall aim.          Looking beyond the survival of                    the breeding patches become
                                           species on single sites, conservation             isolated, either by distance and/or
Continuity of management is the            must operate at the landscape scale               because the intervening landscape is
next vital factor to consider. Species     to be effective in the long-term. There           hostile.
usually occur on a site because its        is now considerable evidence that
past use has created the habitat they      the populations of many if not most               Managing habitats at the landscape
need, and periodically repeating that      butterflies and moths function as                 scale is essential given the evidence
management will be necessary for           metapopulations. This is defined as a             that some species are already
them to persist. This is particularly      collection of local populations which             shifting their geographical range,
important at sites with a long history     occupy discrete habitat patches but               their habitat use and the timing of
of a specific management regime.           which are connected by occasional                 their life cycles in response to climate
Where woodland landscapes have             dispersal of individuals. Each habitat            change. Enabling species to move
become fragmented management
continuity is essential as it is harder
for species to move to alternative
habitats elsewhere.                         What butterflies and moths need
Continuity of management is also                                                             Indeed, adult butterflies may
important because habitats are                                                               be encountered in parts of the
dynamic: they will constantly change,                                                        woodland away from the vital
often over very short time periods.                                                          breeding habitat, especially when
Fundamentally, most woodland                                                                 searching for nectar. In general,
management for Lepidoptera is                                                                Lepidoptera require sheltered,
about working within a cycle of                                                              warm sunny places as adults, often
habitat succession rather than trying                                                        with a nectar source, as well as
to maintain areas in a fixed state                                                           a suitable place to lay their eggs.
over time. In particular, trying to hold                                                     The larvae will then require plentiful
a permanent open area at an early                                                            foodplants, often growing in specific
stage of woodland succession (such                                                           conditions, and will move to a
as that used by Heath Fritillary) is                                                         sheltered or inconspicuous spot
almost impossible. Regular cutting                                                           to pupate before emerging as an
or grazing may keep the site open,                                             Peter Eeles   adult. For highly threatened species
but will usually cause the woodland         A Purple Emperor emerging from its               in particular, understanding where
ground flora to be replaced by a            chrysalis on the underside of a sallow leaf      they spend each of these stages,
grassland community which may                                                                and at what time of year, can be the
not support the target species.             Understanding the life cycles of                 key to effective conservation. Land
Most sites will require a shifting and      butterflies and moths provides                   managers sometimes concentrate
diverse habitat mosaic, created and         an insight into what they need                   on providing the nectar-rich areas
maintained by regular management            from woodland habitats. All                      frequented by adult butterflies
on different parts of the site to           butterflies and moths go through                 (where they are most often seen)
produce younger growth stages               a complex lifecycle from egg to                  at the expense of other habitat
(clearings or short, herb-rich swards)      larva (caterpillar) and then pupa                features. In fact it is rare that nectar
which will in turn provide other            (chrysalis) and adult. Some species              is the factor limiting population
habitats as they re-grow through            spend much longer as an egg,                     growth, and suitable habitat for egg-
woodland succession. Regular                larva or pupa than as an adult,                  laying and larval development is
management provides continuity of           and the habitat requirements of                  usually crucial. Details of individual
short-lived habitat conditions.             each stage may be very different.                species requirements are given in
                                                                                             Section 4.

                                                                                Woodland management for butterflies and moths | 15
Managing woodland for butterflies and moths
Careful planning allows you to work
Sam Ellis

                                                                                                     out what is possible and to set
                                                                                                     priorities. The stages are:

                                                                                                     • Assess what you have (consider
                                                                                                       what habitats and species are
                                                                                                       represented, in a local and/or
                                                                                                       regional context)
                                                                                                     • Decide your objectives and
                                                                                                       priorities (incorporate the needs
                                                                                                       of butterflies and moths alongside
                                                                                                       other interests)
                                                                                                     • Decide how these objectives are
                                                                                                       to be achieved over time, given
                                                                                                       your resources and any legal
                                                                                                       requirements (including felling
                                                                                                       licences, site designations and
                                                                                                       protected species)
                                                                                                     • Monitor progress and examine how
                                                                                                       both vegetation and your target
                                                                                                       species respond to management
                                                                                                       (incorporating what you learn into
                                                                                                       future management)
                                                                                                     Once management is underway,
                                                                                                     be flexible and consider revising
                                                                                                     management prescriptions if they
                                                                                                     do not meet your objectives. It may
                                                                                                     be best to trial new management on
                                                                                                     only a proportion of the site, until
                                                                                                     monitoring results show that it does
                                                                                                     deliver the anticipated conservation
            Open space as part of the wooded landscape at Whitbarrow, Cumbria                        outcomes.

            through the landscape and between          Management planning                           Felling licences
            habitats gives them a better chance                                                      As part of the management plan it
                                                       Management for butterflies and
            of adapting to future changes.                                                           must be noted that a felling licence
                                                       moths often requires a long-term
            The aim should be to restore and                                                         from the Forestry Commission is
                                                       commitment to produce a diversity
            construct landscape networks with                                                        generally required for the felling
                                                       of habitats that will meet the
            interconnected, varied habitats.                                                         of trees, even if the work is part of
                                                       requirements of a variety of species.
            Working at the landscape scale                                                           a grant scheme. Full details are
                                                       It is essential to have clear priorities
            also helps share responsibility for                                                      included in the Forestry Commission
                                                       and defined aims to ensure that the
            management, with each landowner                                                          booklet, Tree Felling – Getting
                                                       main objectives are not lost in the day
            only needing to do a small amount                                                        Permission.
                                                       to day practicalities of management.
            to contribute to the network.
            Coordinating management between
                                                                                                                                                 Susan Clarke

            multiple owners can be challenging,
            however, especially where woodlands
            have been split into many small plots.

            The following sections detail
            management practices that can
            produce the diverse and dynamic
            woodland habitats that best support
            butterflies, moths and a variety of
            other wildlife. The options can be
            adapted to both small and large
            woodlands, and those with primarily
            conservation or commercial forestry
            objectives. While the suggested
            management has conservation aims,
            most will also produce commercial
            products such as coppice poles,
            timber, firewood and other wood
                                                       Forestry operations provide a chance to improve habitat conditions whilst meeting other
            fuels.                                     objectives

            16 | Woodland management for butterflies and mothsmoths
Managing woodland for butterflies and moths
Woodland management relevant to
Dan Hoare

                                                        woodland butterflies and moths of concern

                                                                                                                                                                                                                                                                        Small Pearl-bordered Fritillary

                                                                                                                                                                                                                                                                                                                                                                                                                                    Other moths of concern
                                                                                                                                                                                                                                                                                                          Pearl-bordered Fritillary

                                                                                                                                                                                                                                                                                                                                                              Silver-washed Fritillary

                                                                                                                                                                                                                                                                                                                                                                                                            UK BAP Priority moths
                                                                                                                                                                       White-letter Hairstreak

                                                                                                                                                                                                                                                                                                                                      High Brown Fritillary
                                                                               Chequered Skipper

                                                                                                                                                                                                                    Duke of Burgundy
                                                                                                                                                    Brown Hairstreak
                                                                                                                   Grizzled Skipper

                                                                                                                                                                                                 Black Hairstreak

                                                                                                                                                                                                                                                       Purple Emperor

                                                                                                                                                                                                                                                                                                                                                                                         Heath Fritillary
                                                                                                   Dingy Skipper

                                                                                                                                                                                                                                       White Admiral
                                                                                                                                      Wood White
                                                          Promoting
                                                          diversity of age
                                                                                ••••••••••• ••••••
            Using wood as fuel, in the form of logs,      structure
            woodchip, pellets or charcoal, can
            provide an economic basis for sustainable
                                                          Restoration and
                                                          management of
                                                                                ••••                                                                                                                                •                                                   • ••••••
            management
                                                          coppice
            Managing for different                        Ride and glade
                                                          enhancement
                                                                                ••••                                                                                                                                •                                  •• •                                                                                                    ••••
            species
            It may appear that many woodland
            butterflies and moths of conservation
                                                          Canopy thinning                                                             ••••                                                                                             ••• •                                                                                                                   •                                            ••
            concern have incompatible
            requirements. Some species
            need regular woodland clearance,
                                                          Woodland edge
                                                          buffering
                                                                                ••••••••                                                                                                                                                               •• •                                                                                                    •                                             ••
            while others depend upon closed
            canopy mature trees. This does not
            normally cause problems except                Reinstating
                                                          wetland features
                                                                                                                                                                                                                                                                        •                                                                                                                                                            •
            on very small sites. The following
            management techniques are all
            aimed at increasing the diversity of          Increasing
                                                          deadwood
                                                                                                                                                                                                                                                                                                                                                                                                                                     •
            woodland structure and the diversity
                                                          resource
            of foodplants for Lepidoptera. Diverse
            woodlands will contain a wide variety         Protection of
                                                          veteran trees
                                                                                                                                                                                                                                                                                                                                                                                                             ••
            of habitats that will be capable of
            supporting a variety of species.
            The needs of closed canopy, high              Restoration of
                                                          wood pasture
                                                                                •                                                                                                                                                                                       ••                                                                                                                                                           •
            forest species and those needing
            early successional habitats should
            be seen as complementary rather               Managing deer to
                                                          reduce browsing
                                                                                                                                                    •••                                                                                ••                                                                  •                                                                                                                         •
            than mutually exclusive. Where
            requirements do appear to be
            in conflict, particularly on small
            sites, it will be necessary to assess
                                                          Replacement of
                                                          non-native trees
                                                                                                                                                                                                                                                                                                                                                                                                             ••
            conservation priorities in a local
            context. Conflicting priorities will also
            be more easily addressed within a
                                                          Improving
                                                          connectivity
                                                                                ••••••••••• ••••••
            landscape scale approach to habitat
            management.
                                                                                                                                                                                                                                                                                                                                                                                                                                                             Dan Hoare

            The implementation of sympathetic
            management regimes aimed at
            butterflies will, on the whole, deliver
            conservation for many moths.
            However, moths are a larger and
            more diverse group than butterflies.
            They exploit a far greater range
            of foodplants and habitats and
            additional features may need to be
            considered such as the availability
            of veteran trees, deadwood, fungi,
            lichens and wetland features.
                                                        Butterfly habitats can be ideal for a range of other wildlife - reptiles are common on this
                                                        Grizzled Skipper site on the edge of a young plantation

                                                                                                                                                   Woodland management for butterflies and moths | 17
Managing woodland for butterflies and moths
Coppice
                  An active coppice cycle provides a continuous succession of open
                  space and a varied woodland structure that can create suitable
                  habitats for a range of wildlife
                  Coppice and its history                     timber trees (standards). The            habitats for woodland wildlife. It was
                                                              underwood would be cut on every          not until the late 1800s that markets
                  Coppice is a system of producing
                                                              rotation but the standards would         for coppice products began to
                  wood products that is based on the
                                                              be left to grow for perhaps three        disappear and commercial coppicing
                  ability of trees to re-grow rapidly and
                                                              rotations to produce larger timber. In   diminished. This decline continued
                  vigorously from their cut stumps
                                                              simple coppice, only the underwood       through the 20th century: in 1947,
                  (stools). In coppice management,
                                                              is present and it is all cut on every    142,000ha of actively managed
                  trees and shrubs are cut to the
                                                              rotation. In many areas it was           coppiced woodland were reported,
                  ground, allowed to re-grow, usually
                                                              traditional for domestic animals to      compared to just 23,000ha by 2000.
                  with multiple stems, and then re-cut
                                                              graze within the coupes once scrub
                  on a set rotation. Coppicing appears                                                 By the end of the 20th century,
                                                              growth was more than about 4 years
                  to increase the life-span of trees,                                                  much coppiced woodland had
                                                              old, but nowadays this is rare.
                  indeed some of the oldest coppiced                                                   been grubbed out for farmland,
                  stools have been estimated as more          Coppicing was the main form of           development, or converted to
                  than 1,000 years old.                       woodland management over most            conifer plantations. Other woods
                                                              of lowland Britain until the end of      were abandoned and reverted to
                  Usually a coppice site will be divided
                                                              the 19th century. Its purpose was        closed canopy woodland dominated
                  into many small areas (typically
                                                              to produce a regular crop of small       by mature trees. The resulting
                  called coupes) and each will be cut
                                                              timber and woodland products and,        woodland structure was generally
                  on rotation in such a way that at
                                                              where standards were grown, to           less diverse and more shaded and
                  anytime the site will contain coupes
                                                              supply a smaller amount of larger        provided little habitat for species of
                  of all stages of growth from newly
                                                              timber. Only recently, in the last 30    open woodland. However, since the
                  cut to mature. Coupes typically
                                                              to 40 years, has it been viewed as       1970s, there has been some revival
                  range in size from 0.5 to 3ha. The
                                                              a specialist management aimed            of coppice management, often but
                  length of time between a cut on each
                                                              at providing nature conservation         not exclusively as a tool to provide
                  coupe will vary with the type of wood
                                                              benefits. In particular, it has been     specialist wildlife habitats. There
                  product required and the rate of
                                                              successfully utilised to provide the     is still a small market for coppice
                  growth, but can be anything between
                                                              specialist open early successional       products, together with a growing
                  3 and 50 years.
                                                              woodland conditions required             number of initiatives to promote and
                                                              by some of our most threatened           expand that market.
Morag McCracken

                                                              butterflies such as Pearl-bordered
                                                              Fritillary, Heath Fritillary and High    The value of coppice for
                                                              Brown Fritillary. It has also been       butterflies and moths
                                                              seen as an excellent management to
                                                              maintain habitat for other threatened    The reduction of coppice
                                                              wildlife such as helleborine plant       management has been a major factor
                                                              species, dormice and nightingales.       in the decline of several butterfly
                                                                                                       and moth species, especially the
                                                              The practice of managing                 woodland fritillaries. These species
                                                              woodlands as coppice may go              are dependent on the habitats found
                                                              back into prehistory. Certainly, by      only in the early stages of regrowth
                                                              the time of the Domesday Book in         after a coppice cut, but a full coppice
                                                              1086, coppicing was widespread           cycle is needed to create these
                                                              throughout lowland England.              habitat conditions. A closed canopy
                                                              Coppice systems have been                stage with several years of dense
                  Coppiced Sweet Chestnut in the Blean        repeatedly modified throughout           shade promotes shade tolerant
                  Woods of Kent provides habitat for the      history in response to changing          woodland flora and suppresses
                  Heath Fritillary                            markets. As timber uses changed,         competitive plants. When the coppice
                                                              this drove changes in species choice,    is cut once more it will then provide
                                                              rotation length, and in the proportion   the open ground conditions and
                  Traditionally in Britain, two                                                        foodplants needed, such as violets
                                                              of standards required. However, it
                  systems were used: coppice with                                                      in the case of the Pearl-bordered
                                                              seems probable that whatever the
                  standards and simple coppice. In                                                     Fritillary. Comparatively few butterfly
                                                              system, coppicing took place on such
                  coppice with standards the wood                                                      species utilise the older stages of
                                                              a wide scale that it created a dynamic
                  contains coppiced trees or shrubs                                                    coppice growth, but all stages of the
                                                              mosaic of woodland, from open to
                  (underwood) and also scattered                                                       coppice cycle are of value to moths.
                                                              closed canopy, providing a range of

                  18 | Woodland management for butterflies and moths
Managing woodland for butterflies and moths
For many butterfly species, the                                                                              To reduce shading yet retain the

                                          Amber Rosenthal
composition of tree species in the                                                                           valuable mature tree habitat, there
coppice is not particularly important                                                                        are several options. Standards can
because it is the ground flora that                                                                          be grouped rather than scattered,
supplies their larval foodplants.                                                                            individual standards can be situated
However, the larvae of many moth                                                                             at the corners of coupes (they make
species do feed on shrub and                                                                                 good boundary markers) or small
tree species. The presence of tall                                                                           strips of un-cut woodland can be
standard trees of different species                                                                          left between coupes. These strips
will provide additional habitat.                                                                             should be carefully positioned to add
                                                                                                             shelter without excessive shading.
When is coppicing a                                                                                          A balance between standard quality
feasible option?                                                                                             and shading can be achieved by
                                                                                                             removing some older trees and
It is probably not worth initiating                                                                          allowing younger standards to grow
coppicing within established                                                                                 on in their place.
woodland that has no history
of that management or on sites                                                                               In the long-term, some standards
where coppice has now developed                                                                              should be left uncut to produce
into high forest. The response to                                                                            the veteran tree and deadwood
coppice management is likely to                             Heath Fritillary nectaring on Bramble            habitat required by many moths
be poor and these sites may have                                                                             and other wildlife. Allowing some
developed fauna and flora associated                        Choosing simple coppice or                       short-lived trees such as birch and
with mature woodland that will be                           coppice with standards? Unless                   willow to become standards can
damaged by cutting.                                         planting a new coppice, this decision            produce deadwood habitat quickly in
                                                            will probably depend upon the                    comparison to species such as oak.
Coppicing is almost certainly                               history of the site. Generally when
worthwhile on sites that have a recent                      managing for Lepidoptera the use                 Rotation length: Historically, the
history of this management and that                         of a long rotation coppice with                  length of the coppice cycle and
still have a good density of stools.                        standards is a good choice as it                 the size of coupes varied between
Sites that have been extensively                            creates a diversity of habitats.                 different areas, between woods and
cleared within the last 50 years                                                                             also over time. For conservation
are also likely to respond well to                          Number and rotation of standards:                purposes, factors other than the size
coppicing.                                                  The value of standards in coppice                of the mature coppice stems usually
                                                            can be enhanced by establishing a                take priority. Nevertheless, if there
Coppicing may not be the best                               mixture of tree species and ages. If,            is a commercial product which can
policy in very small woods. The area                        however, the aim is to create sunny              make the conservation management
of potential coppice must be large                          coupes with a varied ground flora                more sustainable, then the desired
enough to support the coupe sizes,                          for breeding butterflies and moths,              crop size must be taken into account
the rotation/s and also the layout                          then the number of standards                     when deciding both rotation lengths
of age classes needed to meet the                           must be strictly limited. One of the             and coupe size.
management aims. For example                                commonest reasons why coppicing
cutting a coupe size of at least 0.5ha                      fails to supply good butterfly habitat           The value of mature coppice stages
per year under a rotation of 7 or 8                         is that too many standards are                   for moths must not be forgotten in
years will require an overall coppice                       present producing too much shade.                the effort to produce open sunny
area of at least 4ha. This can be a                         Excessive shade will also reduce                 areas. If a site is large enough,
problem when managing for some                              coppice growth and damage future                 then a solution can be to operate
of the fritillary butterflies. Although                     coppice viability. It is most important          predominantly short rotations of less
the butterflies require a continuous                        that the total canopy cover of                   than 10 to 15 years but retain a series
supply of newly cut areas, the                              standards is no more than about 10               of coupes that are cut on rotation of
coppice must still go through a                             to 15% of the coupe area.                        20 years or more. Sufficient young
long enough rotation to shade out                                                                            coppice can then be produced while
vegetation as explained above. This                         The appropriate number of standards              also ensuring that a certain amount
problem can be overcome by cutting                          will depend on their canopy cover,               of old coppice is always present.
every other year, or by coordinating                        as each tree species produces a
management across a group of                                different canopy area when mature.               Ideally at least one coupe should be
adjacent woods as one unit.                                 It should also be noted that the                 cut every year, but if labour is short
                                                            shade cast by trees in leaf is often             or if the wood is too small to support
Coppice structure and layout                                underestimated because most                      a full rotation, then a compromise is
                                                            management is carried out in the                 to cut a larger area every two or three
Where coppicing is appropriate,
                                                            winter, and that young specimens                 years.
the following factors must be
considered to make it successful and                        will quickly expand their canopy size
sustainable:                                                once in an open situation. Generally
                                                            15 large standards per hectare
                                                            should be the absolute maximum
                                                            when managing for butterflies.

                                                                                                    Woodland management for butterflies and moths | 19
Managing woodland for butterflies and moths
Advantages and disadvantages of different rotations:                                    Avoid creating narrow coupes, unless
                                                                                        it is part of management along a
                                                                                        ride edge. These are likely to have
 Short rotations                                                                        the same problems with shading,
                                                                                        encroachment and browsing damage
 Advantages              Can maintain the supply of young growth areas,                 as small coupes. Aspect will affect
                         often better for butterflies                                   the amount of sunlight falling on
 Disadvantages           Labour-intensive in large woods                                the coupe, and north or east-facing
                         In some cases may be too short for the underwood               coupes may need to be larger to
                         to be of commercial value                                      allow light to penetrate.
                         May not supply habitat for species that require                On a practical level, it is a good idea
                         older coppice                                                  to mark out the corners of every
                         Growth may not get dense enough to shade out                   coupe with permanent posts or by
                         the ground flora                                               pollarding trees, and to produce a
                                                                                        map of the proposed coupe rotation.
 Medium to long rotations                                                               The length of most coppice rotations
 Advantages              Longer rotations create a wider range of habitats              means that the people doing the
                         than short, often better for moths                             cutting will probably change from one
                                                                                        cycle to the next, so markers and a
                         Can make coppicing economically viable in
                                                                                        map will be needed to guide future
                         large woods
                                                                                        management.
 Disadvantages           In some cases may be too long for the underwood
                         to be of commercial value                                      Common failures
                         Can be difficult to maintain the supply of young               and problems
                         growth areas
                                                                                        • Initiating management without
                                                                                          defining the aims and objectives
Size of coupe: For the coppice-             year, although a larger area is needed      • Underestimating the resources
dependent Lepidoptera, the advice           for the habitat to be rotated through         needed. Work is abandoned during
is not to cut less than 0.5ha per year      the full coppice cycle.                       the rotation because of labour
per site. The main factor is to achieve                                                   shortages
the minimum area of breeding habitat        Layout: When selecting the coupe            • Short-term planning. Rotational
required to support a population            areas, any special, legally protected         coppice will not deliver
of the target species. This will be         or locally unique features and habitats       conservation unless a long-term
provided by the most recently cut           that might be damaged or removed              commitment is made to continue
coupe together with a number of the         by coppicing should be retained. For          the management for many years
previously cut coupes depending             example, stands of mature Aspen
                                                                                        • Isolation. Habitat created is too
on vegetation development. The              are uncommon and have high value
                                                                                          distant for the target species to find
appropriate flora needed for a              for specialist invertebrate species,
                                                                                          and colonise before the habitat is
species such as Pearl-bordered              including moths. Retain any special
                                                                                          lost to succession
Fritillary is very likely to exist only     or uncommon trees, veteran trees or
                                            old pollard specimens.                      • Sites or coupes are too small to
in small patches within any single
                                                                                          provide a sufficient area of breeding
coppice coupe and this must be
                                            Coupes are best situated next to              habitat. Suitable ground flora fails
taken into account.
                                            flower-rich sunny rides. These will           to develop on otherwise suitable
The total area cut each year can            supply nectar, act as a seed reservoir,       coupes
be divided into as many coupes as           provide insect flight paths between
                                                                                                                                   Mark Parsons

required, but single coupes of less         coppice areas and also allow access
than 0.5ha are usually too small to         when cutting. For butterflies, it is best
supply suitable unshaded, early             if coupes can be cut sequentially
growth habitat. They are generally          with areas cut in subsequent years
shaded by adjacent woodland                 being no more than 300m away. This
and are quickly encroached by the           is essential for many of the butterfly
established vegetation at the coupe         species dependent on early stage
edges. Small coupes are often heavily       coppice as they are often poor at
browsed by deer and rabbit, as these        finding and colonising new areas.
animals prefer not to venture far from
                                            Cutting slightly irregular coupe
cover so avoid the open spaces of
                                            boundaries will increase the edge
large cut areas.
                                            habitat and may be beneficial in
Surprisingly, if the habitat is suitable    adding another variation in structure
then many butterfly species can have        to the woodland landscape. For the
viable populations within only 1 to         same reason areas or small strips           The Common Fan-foot is often associated
                                            of uncut woodland can be retained           with rotational coppice management,
2ha of coppice habitat within any one                                                   although it probably breeds on oak
                                            between coupes, but avoid shading
                                                                                        standards rather than the underwood
                                            the coppice.                                species

20 | Woodland management for butterflies and moths
Managing woodland for butterflies and moths
• Leaving too much shade. Typically

                                                                                                                                 Dan Hoare
  too many standards are retained, or
  coupes are too small
• Re-cutting before allowing the
  coppice to go through the full
  cycle. Re-coppicing part way
  through the cycle is sometimes
  attempted as part of emergency
  conservation measures for
  particularly threatened early
  succession species. This rarely has
  the desired result of restoring the
  early successional ground flora and
  tends to result in a uniform grassy
  sward of little value to the target
  species. The closed canopy stage
  is essential
• Excessive deer or rabbit browsing.
  High levels will damage or prevent
  regrowth. Damage may be reduced
  by cutting large coupes, as deer
  and rabbits prefer to be close
  to cover. It may be necessary to
  protect individual stools or fence
  entire coupes through the stage
  of young growth (see “Managing
  deer” for a more detailed
  discussion)
• Damaging the site during cutting
  and clearing. Use as few bonfire
  sites as possible. Locate them
  carefully where they will not          A coppiced Sweet Chestnut stool showing vigorous regrowth two years after cutting
  damage stools or other habitats
  such as flower-rich grassland.
  Re-using previous burn sites is        in most practical guides to coppicing.       New coppice woodland
  recommended                                                                         It is possible to create new coppice
                                         Low intervention: Neglected
• Failure to monitor results and         coppice could also be left to                by planting or direct sowing, but
  incorporate successes or failures      eventually take on the characteristics       unless the area has been wooded
  into future management                 of a natural forest. In this case, it        in the very recent past then creating
                                         might be worth thinning some of              the suitable flora required by many
                                         the coppice by singling, that is by          of the woodland Lepidoptera may be
Restoring neglected                                                                   difficult. Many species of butterflies
                                         removing all but the best stem on
(over-grown) coppice                     each stool. This is generally used           and moths will also have problems
The choice of management in              to try and produce good quality              colonising a new coppice if it is
neglected coppice (sometimes             timber but in the context of habitat for     any distance from their existing
called stored coppice) is either         Lepidoptera it is likely to speed up         populations.
to re-coppice, to manage as low          the creation of large mature trees that
intervention (leave to develop to                                                     If new coppice woodlands are
                                         will provide additional structure and
high forest) or to clearfell and then                                                 to be created specifically for
                                         habitat.
re-establish a new coppice or a new                                                   conservation then they are best
broadleaved woodland.                    Clearfell and replant: Another               sited next to existing semi-natural
                                         option is to clearfell the overgrown         woods, otherwise it will be difficult
Re-coppice: The choice to re-            coppice and replant with native trees        to establish the suitable woodland
coppice will depend on the time          at fairly broad spacing, allowing the        flora and fauna required by the rarer
since the last cut, the condition and    underwood to regrow as shrub layer.          Lepidoptera.
density of the stools. Many sites with   The site can then be managed as
overgrown coppice have shown a                                                        The creation of new, short rotation
                                         either coppice with standards or left
surprisingly good response to re-                                                     simple coppice for biofuels is now
                                         to develop as mature woodland. In
cutting, although stool density may                                                   being actively promoted (mainly
                                         general, this option seems to carry
have to be increased by planting                                                      willow or poplar species). It is not
                                         few benefits for conservation over
or by encouraging vegetative                                                          yet clear if this process will hold
                                         re-cutting. It is expensive in cost
propagation. Techniques for creating                                                  any benefits for the conservation of
                                         and labour and importantly unless
new stools from the old stumps such                                                   Lepidoptera.
                                         small areas are clearfelled on a long
as layering and stooling, as well as     rotation the risk of damage to the
re-spacing the stools, can be found      existing flora and fauna is high.

                                                                            Woodland management for butterflies and moths | 21
Managing woodland for butterflies and moths
Rides
A ride is any linear track or opening within the wood and includes
the whole area between the mature trees on either side. That is the
surface of the ride itself, any ditches and also the vegetation on the
ride verges (grassland, scrub or coppice regrowth).

Most woods have at least some               However, this limited amount of

                                                                                        Dan Hoare
rides for access, shooting activities       coppicing is usually not adequate on
and increasingly for leisure activities     its own to maintain the very specialist
such as walking, horse-riding and           early-stage species such as the Heath
cycling. In commercial forestry, rides      Fritillary.
do serve a purpose as fire breaks
but are primarily to give access for        Ride verges may have associated
forestry operations, including timber       ditches and these give not only
extraction. As forestry machinery           additional structural diversity, but also
becomes larger, some of these               can be a source of wetland or damp-
rides have been surfaced to create          loving plant species. The ditch banks
woodland roads.                             are often particularly warm, sunny
                                            habitats.
Why are rides important for
Lepidoptera?                                Management of rides
                                            For butterflies and moths, the four
In many modern woodlands
                                            key factors are the:                                    Herb-rich vegetation in ride edges
(particularly in conifer plantations),
open areas are largely confined to                                                                  provides nectar, roosting sites and larval
                                            • amount of shade                                       foodplants
rides and glades and these have
                                            • structure of the vegetation
become a refuge for the butterflies                                                                 than those orientated north to south.
and moths that need open sunny              • species composition of the ground-                    As a rough guide, ride width must
conditions. Some of these species             layer vegetation                                      be 1.5 to two times the height of the
are woodland or wood edge                   • species composition of the ride                       surrounding trees to provide good
specialists, but many will also be            edge trees and shrubs                                 unshaded butterfly habitat (width is
found in the wider countryside. Rides                                                               measured from the base of the crop
also usually provide the best way of        Although open sunny rides with less                     trees on either side). There can be
connecting different habitats within        than about 20% direct shade are                         scrub growth within this width as this
woodlands, and prevent species              required by many butterfly species,                     tends to have only a slight shading
having to move through unfavourable         other Lepidoptera (including some                       effect.
conditions to reach the next habitat        butterflies) prefer partially or even
patch. Providing these areas can            heavily shaded areas. Thus a variety                    Along some ride networks there may
be suitably managed, their value for        of shade conditions and similarly a                     be a constant mix of different tree
Lepidoptera can be enormous.                range of ride widths and orientations                   heights with many patches of low
                                            will need to be produced and                            growth and in such cases the width
Rides potentially provide a large                                                                   and orientation will be less important.
                                            maintained. Even a single species
diversity in structure and vegetation
                                            will require a range of rides to meet                   Practical methods for achieving the
within a small zone. They combine
                                            its requirements under different                        required ride structure are given
sheltered grassland with typical wood
                                            conditions. For example, the Wood                       below. First the rides might need
edge habitat and this can provide
                                            White tends to use areas with less                      to be opened up or even created,
diverse areas of nectaring and
                                            than 20% shade, but one study                           then consideration must be given to
breeding. On many sites they also
                                            suggests that it not only moves                         ongoing management.
contain relics of habitat types that are
                                            between rides of different orientations
now scarce in the wider countryside
                                            during the day following the sun,
(for example; unimproved grassland,
                                            but also on windy days it chooses
                                                                                                    Widening existing rides
wetland habitat, heathland) and so                                                                  Often the first priority in a wood is to
                                            sheltered but slightly shady rides,
can support the associated butterflies                                                              increase ride width to reduce shade
                                            over the open sunny rides.
and moths.                                                                                          levels. However, this should target
                                            The amount of shade on a ride will be                   areas with simple structure and dense
When rides are managed with a
                                            determined by its width, its orientation                crops close to the ride, to avoid
scrub-zone cut as coppice, then
                                            and the surrounding tree height. East                   damaging valuable semi-natural
some of the species associated with
                                            to west orientated rides will receive                   woodland and the species using the
coppice rotation will use this habitat.
                                            more sun during summer months                           current ride edges.

22 | Woodland management for butterflies and moths
Managing woodland for butterflies and moths
If left to themselves, rides will quickly
Alan Reid / Forestry Commission

                                                                                                                             revert to high forest. In order to
                                                                                                                             create and maintain diversity active
                                                                                                                             management will be required.
                                                                                                                             Several cutting regimes have been
                                                                                                                             developed to specifically meet the
                                                                                                                             needs of butterflies and moths: -

                                                                                                                             Two zone system: This is similar
                                                                                                                             to the rideside management used
                                                                                                                             in commercial forestry. It is low
                                                                                                                             cost, low maintenance, but also
                                                                                                                             comparatively low in structural
                                                                                                                             diversity. It does not produce the
                                                                                                                             good scrubby margin needed by
                                                                                                                             many moth species, although under
                                                                                                                             some rotations, patchy scrub is likely
                                                                                                                             to develop. It can provide good open
                                                                                                                             grassland habitat for butterflies.
                                  Ride widening for Wood Whites at Bury Ditches, Shropshire
                                                                                                                             The central ride zone is cut once or
                                                                                                                             twice a year (unless it is surfaced) to
                                  In conifer plantations, often the only       Creating new rides                            maintain it as an access route.
                                  remaining deciduous trees and
                                                                               In semi-natural woodland with no
                                  shrubs are located in a thin margin                                                        A zone (2 to 5m wide on each side)
                                                                               pre-existing rides it is suggested
                                  along the crop edge, and this will                                                         either side of the central zone is cut
                                                                               that a most careful examination of
                                  be removed by widening. Potential                                                          on 4 to 7 year rotation, but this is
                                                                               the site is required before creating
                                  damage can be reduced if only                                                              carried out in sections so that only a
                                                                               ride habitat. If the site is an actively
                                  short areas are done at a time and                                                         portion is cut each year. Importantly,
                                                                               managed (or recently managed)
                                  substantial lengths of the original                                                        the whole ride, or even all of one
                                                                               pasture woodland or if it has a rich
                                  ride edge habitat are left between                                                         side of a ride should not be cut in the
                                                                               or uncommon ground flora, then
                                  widened sections.                                                                          same year.
                                                                               ride creation may not be suitable.
                                  Retain specimens or groups of                As always, consider the aim of the
                                                                               management and examine any                    Further habitat variety can be created
                                  locally uncommon trees (uncommon                                                           by simply introducing two different
                                  in terms of either species or age). A        conflicts that the new management
                                                                               might produce.                                cutting rotations, cut some margins
                                  patch of Aspen for example, may be                                                         on a short rotation (4 years) and
                                  the only breeding area on the site                                                         some on a long rotation (7 years).
                                                                               Try to create wide, gently curving
                                  for several species of moth. Sallows
                                                                               rides with varying orientations along
                                  provide an important nectar source                                                         Three zone system with coppice:
                                                                               their length. Plan the routes of new
                                  for many insects in spring and may                                                         This is a more complex regime that
                                                                               rides carefully to avoid conflict with
                                  provide breeding sites for Purple                                                          can provide an excellent mosaic of
                                                                               existing features. Any special, legally
                                  Emperor and many moths, and                                                                habitat for both butterflies and moths,
                                                                               protected or locally unique features
                                  should be retained where possible.                                                         including habitat for some of the
                                                                               and habitats must be protected.
                                                                               Retain any special or uncommon                canopy-living species.
                                  An often-stated objection to ride
                                  widening is the wind tunnel effect           trees, veteran trees or old pollard           The central ride zone is cut once or
                                  - the channelling of wind between            specimens.                                    twice a year (unless it is surfaced) to
                                  stands of tall trees. This can have                                                        maintain it as an access route.
                                                                               After clearing, the stumps in the
                                  an impact on a timber crop and may
                                                                               centre which will become the grass/           A zone of tall grassland vegetation is
                                  reduce the sheltered conditions
                                                                               herb zones can be removed, ground             created either side of the central zone
                                  favoured by many Lepidoptera.
                                                                               down or treated with herbicide.               (2 to 5m on each side). This zone
                                  Ride layouts with curves rather than
                                                                               Stumps along the margin should not            is cut, in sections, on a 3 to 4 year
                                  straight lines will not suffer from this
                                                                               be treated but allowed to re-grow and         rotation with opposite sides being
                                  effect, but many woods have straight
                                                                               then managed as coppice.                      cut in different years. As with the two
                                  line, grid system rides. Wind damage
                                  can also occur after ride widening, as                                                     zone system, it is important that the
                                  wind-hardened trees on the edge are          Creating and maintaining                      whole, or even one side of a ride is
                                  removed, exposing weaker trees that          verge habitat                                 not cut in the same year.
                                  are then damaged or blown down.
                                  These issues can be minimised by             The best ride edges graduate from             A mixed species scrub zone (5
                                  widening using scalloped edges so            tall trees, to a variety of shrubs, to tall   to 10m on each side) is created
                                  that the ride is not uniformly wide and      herb-layer vegetation then grassland          between the tall grassland zone
                                  it remains sheltered. An alternative         flora. It will also include some bare         and the woodland. This is managed
                                  is to leave “squeeze-points” along           ground and ideally there will be              rather like coppice to provide mixed
                                  a ride, retaining occasional mature          canopy gaps and height variation              ages of woodland succession. A
                                  trees which break up the exposed             within the scrub zone.                        rotation of 8 to 20 years is suggested
                                  profile.                                                                                   and as with the adjacent zone, it is

                                                                                                                    Woodland management for butterflies and moths | 23
cut piecemeal.

                                                                                                                                       Dan Hoare
                                            A three zone ride edge
As with coppice, the length of rotation
must be balanced between providing
sufficient open newly-cut woodland
habitat and allowing the regrowth to
shade out the ground vegetation so
that sparse vegetation/bare ground
conditions are produced after each
cut. The ideal cutting rotation will
depend on the growth and density of
the scrub. If scrub density or species
variety is poor then the zone can be
planted, or temporary fencing can
be used for protection while tree
seedlings establish naturally.

Each section can be 50-100m in
length dependent on the size of the
woodland, and both section length           The three zones of a south-facing ride edge in a Hampshire woodland. The central ride
                                            zone (at right in this image), cut once a year, is grassy but holds plenty of herbs and
and cutting rotations can be varied
                                            bare ground, supporting Grizzled Skipper. The tall grassland zone, cut every 3 years,
across a woodland.                          has a mixture of bracken, herbs and grasses, and at this site supports Pearl-bordered
                                            Fritillary. The mixed scrub zone at the back, cut as coppice, is predominantly birch and
Further enhancements to                     provides breeding sites for Argent & Sable.
basic ride management
The following can be used along                                                            or to produce patches of early
rides and forest roads in combination       Including rideside native trees:               successional vegetation. Varying
with the two and three zone cutting         Native broadleaved trees can be a              sizes of patches could be selected
systems described above, or as              rare habitat in coniferous plantations.        on rotation and mechanically scraped
stand-alone management:                     Even within mixed or deciduous                 free of all vegetation, making sure
                                            woodland older trees may be                    that a degree of soil disturbance also
Scalloped edges: A series of                uncommon. Many Lepidoptera seem                occurs. Allowing scuffing or scraping
rideside bays, often called “scallops”      to require mature trees that are               by ride-cutting machinery can also
are created along the ride verge/           slightly separate from woodland and            create bare ground habitat on a
tree boundary. These not only widen         that have ground-vegetation around             small scale. Small scrapes along the
the ride to reduce shading but also         their trunks rather than underwood.            top of roadside banks are effective
provide shelter and increase the                                                           at establishing the low growing
length of edge habitat.                     A few, mixed species deciduous                 foodplants of the Grizzled Skipper,
                                            standard trees can be planted or left          and more extensive scarification and
A suitable size, as a very rough guide,     to grow in the ride margins (making            rotovation techniques have been
is approximately 30 to 50m long by          sure the canopy cover along a                  used to improve floral diversity in the
10 to 20m deep. If the scallops are         rideside or within a scallop is less           Brecks of Norfolk and Suffolk.
cut opposite each other then they           than 10 to 15%).These trees can
provide a maximum open area,                be in small groups or as scattered             The timing of verge cutting: The
essentially widening the ride. They         individuals.                                   time of year and frequency of cutting
can also be staggered, alternatively                                                       plays a key role in determining the
or randomly along a ride.                   Bare ground areas: Many                        composition and structure of ride
                                            Lepidoptera require some bare                  vegetation, but this is also affected
They can be managed to produce              ground patches to provide the                  by soil type so the effect will vary
one of two habitats, scrub or               suitable hot-spot microhabitat around          between sites. Cutting at any time of
grassland, the difference is in the         their foodplant or for basking. It also        year, whatever method is used to cut
frequency of cutting. A scrub scallop       provides structural diversity as well as       and remove material, is very likely
is managed on a coppice-style               floral diversity by encouraging seed           to affect or destroy some life stages.
rotation in the same way as a scrub         germination. Several larval foodplants         It is therefore important to only cut
zone in the three zone system. A            for scarce Lepidoptera are associated          part of the verge in any one year and
grassland scallop is managed on the         with regular ground disturbance, such          to monitor the impact on any target
same system as the tall grassland           as Wood Spurge which supports                  species. If the only breeding area
zone in the three zone system.              the Drab Looper moth. Activities or            for a species is in the portion due to
                                            managements that regularly result              be cut that year, consider whether
Scallops can be used as a
                                            in areas of bare ground can be most            cutting can be delayed to allow
management in its own right or
                                            useful, as long as they only affect a          colonisation of nearby habitat.
incorporated to add extra diversity
                                            part of the habitat in any given year.
within a three zone system (see case
study “Chiddingfold Forest”).               It can sometimes be useful to
                                            create areas of bare ground under
                                            controlled conditions, to perhaps
                                            encourage seed germination

24 | Woodland management for butterflies and moths
General recommendations are as            Combining conservation                          will regularly remove all breeding
follows:                                                                                  habitat along the road edge. Timing
                                          management with forestry                        forestry operations to the needs
Cutting grassland vegetation:             operations                                      of Lepidoptera is also not usually
Cutting during the autumn is usually      Forest roads are maintained to allow            possible, although often some
recommended, to avoid damage              good access for forestry machinery              compromise can be reached. It is
while insects are most active in          so they are usually wide and kept               therefore vital that similar habitat
summer, and to allow plants to set        clear of overhanging canopy. This               is available within a more secure
seed. In the past, however, most          also means that they can have high              location. If there are no refuge
rides would have been maintained          potential as Lepidoptera habitat.               habitats nearby to provide continuity,
either by grazing or by cutting for       However, a forest road with its                 then local extinction of species is
hay in July or August. On particularly    verge is a working environment and              highly probable.
fertile sites with strong ground-flora    conservation management needs
growth then some cutting during           to take this into account. If forest            Features such as turning circles
July or August could be considered,       roads and associated features are               and loading bays can, like the road
as there is evidence that this            not maintained efficiently, then their          edge habitat described above,
encourages a broader range of flora.      maintenance incurs extra cost.                  provide good breeding habitat for
Alternatively, some cutting during the                                                    species requiring sparse vegetation
spring or very early summer would         Many are managed on a similar                   and bare ground, but this habitat
remove early grass growth yet still       cutting regime to the two zone                  will be damaged or destroyed at
allow many species to flower later.       system. The alternative three zone              intervals. This is also the case for
                                          system can result in vegetation                 most roadside ditches, created to
Spring or summer cutting may be           encroaching on the road surface                 take the run-off from the surfaced
beneficial in the long-term but will      as might occur on a 3 or 4 year                 roads. These ditches, their banks and
temporarily remove some breeding          rotational cut. In this case a slightly         associated vegetation can provide
habitats and nectar sources. This         modified three zones can be used                habitat for species such as Wood
issue can be limited by only cutting a    whereby the central zone is moved to            White, but they will be regularly re-
small proportion of the site each year.   a narrow strip (1 to 2m on each side)           dug, with spoil removed to the ditch
Whatever cutting period is decided, it    along either side of the road surface.          banks or verge edge.
is worth building a degree of variation   This strip can then be maintained
into the management because               by annual or more frequent cutting.             Forestry activities can have an impact
different plant species will respond      For ease of mowing, this strip can              on verge habitats, for example where
to different regimes. Deciding the        additionally be cut whenever the                vehicles use the verge during timber
timing, frequency and rotation of         adjacent zone of tall grassland flora           extraction or where wood is stacked
cutting, together with an aim of what     is cut.                                         on the ride edge. Minimise impacts
structure you are trying to create, is                                                    by:
more important than defining precise      Essential forestry operations may
cutting heights.                          have significant adverse impacts on             • Ensuring that the entire ride
                                          Lepidoptera breeding areas along                  network is not managed uniformly
It is best to remove the cut material     rides. The road/verge edge tends                  in any one year
if at all possible (some forage           to receive regular disturbance as               • Providing refuge breeding areas for
harvesters can cut and gather the         all operational forest roads have                 the species that may be affected
vegetation in one pass). Cuttings or      a periodic maintenance (grading)                • Monitoring breeding areas used
mulch can smother the remaining           during which this zone is scraped                 by susceptible species so that
vegetation and increase nutrient          back to bare ground. This regular                 potential problems can be avoided
build-up which will reduce floral         ground disturbance often provides                 or mitigated
richness. Cuttings can be raked into      good breeding habitat for species
heaps, but these must be carefully                                                        • Protecting sensitive areas with
                                          such as Grizzled and Dingy Skipper
sited to minimise the effect on the                                                         temporary fencing during forestry
                                          but road grading cannot usually
rideside vegetation. Blowing or                                                             work
                                          be carried out piecemeal and
raking the material into the adjacent
crop can be considered in coniferous
                                                                                                                                      Dan Hoare

woodland, but within deciduous
woodland (or where there is a
managed rideside scrub zone) this
would cause damage to the ground
flora under the canopy.

Cutting scrub vegetation: Ride
edge scrub zones should be treated
like coppice and are best cut during
the winter. The section on coppice
includes advice on the disposal and
burning of cut material.

                                          A wide sunny ride provides ideal breeding conditions for Pearl-bordered Fritillaries at a
                                          Forestry Commission site in Sussex

                                                                                Woodland management for butterflies and moths | 25
Glades
Woodland glades are permanent or semi-permanent areas that
contain few or no trees but are surrounded by woodland. They are
usually non-linear, in contrast to rides and wayleaves, and are distinct
from young plantations or clearings containing young woodland.
Why are glades important for                suitable ground flora and also the

                                                                                                                                    Dan Hoare
                                            movement of Lepidoptera into these
Lepidoptera?                                new habitats.
Glades provide a larger area of open
habitat than is found in rides, which       Management of glades
may be important for the colony
                                            Glades can be treated in the same
structure of some butterflies. Several
                                            way as rides to provide a range
species can reach high population
                                            of vegetation types, from open
densities in glades but will only
                                            grassland through to scrub. A scatter
ever occur in rides in low numbers.
                                            of tall trees can also add diversity, but
The Marsh Fritillary, for example,
                                            restrict canopy cover to less than 10%
rarely breeds on rides even when its
                                            of the glade area.
foodplant is abundant, but will use
damp grassy woodland glades of at           The specific management will depend
least 1ha, and does best when there         on the permanency of the glade.
are a series of such glades.                A glade can be a temporary open
                                            space, that is cut and then allowed
Creation of glades                          to re-grow, or a more permanent
Glades can be created either linked         opening where regrowth is controlled
to the ride complex, or separate and        or suppressed.                              Scrub cut on rotation within a permanent
                                                                                        glade provides a varied age structure and
located within the mature or semi-                                                      sheltered conditions
mature woodland. Overall the same           If the glade is to be managed as
principles of width, shading and crop       a temporary open space then the
                                                                                        also as small patches scattered
height apply as discussed for rides,        habitat produced is similar to that
                                                                                        across the glade. This can be
also the same concerns for cutting          created under coppice. Open bare
                                                                                        enhanced using irregular, piecemeal
new glades within natural or semi-          ground conditions will dominate at
                                                                                        cutting of the patches of scrub on
natural woodland. Glades linked to          first, regrowth then produces scrub
                                                                                        anything between an 8 to 20 year
ride systems are better connected to        and finally mature woodland. Such
                                                                                        rotation, depending on the rate of
the wider habitat network, whereas          a light to shade cycle will maintain
                                                                                        growth at the site.
glades within mature woodland may           the typical woodland flora and will
be more isolated and difficult for          prevent the vegetation becoming             On a box junction, each corner
some species to locate.                     grass dominated.                            section could receive a different
                                                                                        cutting regime. Some cut every 1
As part of the ride complex: With           Management of true permanent open
                                                                                        to 4 years to create grass and herb
minimal tree removal a good sized           space in woodland has much in
                                                                                        dominated vegetation. Others cut
glade can be created by simply              common with unimproved grassland.
                                                                                        on a rotation longer than 4 years to
enlarging the intersection of two           Repeated cutting, mowing or grazing
                                                                                        allow the development of scrub. If
rides to produce a “box junction”           will be needed to prevent scrub
                                                                                        the rotation is long enough to allow
or “corner glade”. Usually all four         growth and without a period under
                                                                                        the scrub to shade out the ground
corners of the junction are removed,        dense canopy shade the vegetation
                                                                                        vegetation, then after re-cutting,
but sometimes only two and the              usually becomes grass dominated.
                                                                                        valuable early successional woodland
different segments to the glade do                                                      habitat can be created for species like
                                            If large enough, then a mixture of
not have to be the same size.                                                           Pearl-bordered Fritillary.
                                            permanent and temporary open
Separate from the ride complex:             space can be created across the
                                                                                        On some sites there may also be
It can involve a considerable felling       glade. Such a mosaic habitat
                                                                                        an option of using domestic grazing
of timber to create a suitably sized        structure is highly attractive to many
                                                                                        animals within enclosures. Grazing
glade. Generally glades should be           Lepidoptera and mimics that found
                                                                                        creates a very different type of
at least 0.25ha and preferably 0.5 to       along a natural wood edge. The
                                                                                        vegetation from cutting, so adding
2ha in size. Grouping glades within         grassland areas could be cut on short
                                                                                        diversity. Grazing is more practical in
the same area and providing some            rotations (1 to 4 years) and some
                                                                                        woodland glades than rides and was
connectivity with an existing open          scrub could be allowed to develop
                                                                                        often the traditional management.
feature will aid the establishment of       not only along the wood edge, but
                                                                                        The aim would be to create diverse

26 | Woodland management for butterflies and moths
Susan Clarke
A large permanent glade among planted conifers

vegetation, while preventing or            To save expense, often only the            south-facing edges and rotational
reducing the growth of scrub and           tallest scrub (that which will breach      cutting of sections rather than
trees. Rotational grazing can give a       clearance thresholds) is cut at any        uniform management. An alternative
high level of control because stock        one time. This can create a mosaic         is to cut and treat stumps to create
can be moved periodically around a         of small scrub of various ages             more permanent open areas,
single large glade or from glade to        together with open, cleared areas.         although this will require similar
glade. Grazing is discussed in more        It is often the only habitat of its type   management to a ride or glade to
detail in the following pages.             within the woodland and can be             maintain floral diversity.
                                           excellent habitat for Lepidoptera. In
Wayleaves                                  Scotland, for example, wayleaves are
                                           extremely important as habitat for                                                      Rob Petley-Jones
Wayleaves are the areas beneath
power lines, and within woodlands          the Chequered Skipper and Pearl-
these areas are regularly cut to keep      bordered Fritillary in otherwise dense
scrub/tree growth away from the            plantations or regenerating native
cables. This effectively means that        woodland.
wayleaves within woodlands are
                                           The management of wayleaves
linear glades managed on a short
                                           is often outside the control of
coppice rotation, which can provide
                                           woodland managers, but if scarce
important wildlife habitat and improve
                                           butterflies or moths are known to
connectivity between other open
                                           be using the site it is worth passing
areas. Widths vary, but most are
                                           on specific recommendations to the
10 to 20m wide. They are typically
                                           power company. Where pipelines
managed by the power company
                                           are buried beneath the surface the
or a contractor, whose objective is
                                           area above may also be kept clear
to keep any vegetation a minimum
                                           to allow access and prevent root
distance away from cables and other
                                           damage, providing very similar             The moth Anania funebris breeds on
equipment. This means that rotation
                                           habitat opportunities. Best practice       Goldenrod in glades, rides and wayleaves
lengths are not set, but depend on
                                           wayleave management is similar to
the height of the cables and the
                                           ride management and includes the
growth rate of the scrub.
                                           creation of scalloped edges along

                                                                             Woodland management for butterflies and moths | 27
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