Background information and definitions
Coppicing is a traditional woodland management technique, used to harvest the young, fast-growing stems of particular tree species, such as hazel. It involves repeatedly felling trees at the base and allowing them to regrow for a number of years. Coppicing removes some of the canopy, allowing light in to the woodland floor, replicating the natural creation of woodland clearings. This may benefit butterflies and moths by encouraging the growth of food plants on the woodland floor, or by creating sheltered, sunny sites for basking and territory defence.
Supporting evidence from individual studies
A replicated, site comparison study in 1980–1984 in 24 woodlands in Kent, UK (Warren 1987, same experimental set-up as 3) found that recently coppiced woodland patches had a higher abundance of heath fritillary Mellicta athalia than areas coppiced longer ago. The number of heath fritillary recorded 2–4 years after a site had been coppiced (96–2,187 individuals/site) was higher than 5–11 years after coppicing (0–46 individuals/site). Populations in vigorous coppice became extinct six years after management if no further coppicing was conducted, but some populations in poor coppice survived for nine years after management. At one site, where new 1–3 ha areas of wood were coppiced annually from 1979, the number of heath fritillary was 1,100 in 1985, compared to <20 in 1980 (statistical significance not assessed). Twenty-four woodlands were coppiced intermittently, 1–11 years before surveying. From 1980–1984, the number of adult heath fritillary at each site was estimated from a combination of counts on regular transects throughout the season, single counts around the peak flight period, and mark-recapture of individuals.Study and other actions tested
A replicated, site comparison study in 1986 in a mixed woodland in Dorset, UK (Robertson et al. 1988) found that open, coppiced areas within a woodland had a higher abundance and species richness of butterflies than unmanaged broadleaf woodland or conifer plantation, but fewer butterflies than managed clearings. In open, coppiced woodland, both the abundance (25 individuals/km) and species richness (16 species) of butterflies were higher than in unmanaged broadleaved woodland (abundance: 2 individuals/km; richness: 4 species) or conifer plantations (abundance: 5 individuals/km; richness: 2 species). However, the most butterflies were recorded in managed clearings (abundance: 89 individuals/km; richness: 19 species). See paper for individual species results. The woodland contained patches managed in four ways: open woodland with coppiced hazel; unmanaged broadleaved woodland with unmanaged hazel coppice; conifer plantation; and managed clearings (30–50 m wide and 100–150 m long) which were cleared of scrub every three years. In July–August 1986, butterflies were surveyed six times on each of twenty-two 200-m transects: eight in open, coppiced wood, six in unmanaged wood, four in conifer plantation and four in managed clearings.Study and other actions tested
A before-and-after, site comparison study in 1980–1989 in two woodlands in Kent, UK (Warren 1991, same experimental set-up as 1) reported that a protected woodland managed by coppicing established a large population of heath fritillary Mellicta athalia, while over half of the colonies in a privately owned, unmanaged wood went extinct. Results were not tested for statistical significance. After four years of coppicing in one protected wood, the number of heath fritillaries peaked at 2,000 adults, and stabilized at around 800 adults after nine years, compared to “just a few individuals” when management began. In an unmanaged, unprotected wood, there were 800 adults across nine colonies in 1989, compared to over 10,000 adults across 20 colonies in 1980. From 1980–1989, a woodland protected as a National Nature Reserve was managed by coppicing one or two plots (1–5 ha) each year on a 15–20-year rotation. Plots were connected by wide rides and permanent glades. A nearby, privately owned woodland was not managed. From 1980–1989, butterflies were surveyed most years on timed counts along a zig-zag route covering the known flight areas at each site. The total yearly population at a site was estimated by multiplying the peak population count by three.Study and other actions tested
A replicated, site comparison study in 1990–1991 in 52 woods in southern England, UK (Clarke & Robertson 1993) found that populations of pearl-bordered fritillary Boloria euphrosyne and small pearl-bordered fritillary Boloria selene were more likely to persist for up to 20 years in woodland containing more actively coppiced areas or young plantations. Woodlands with larger areas of active coppicing or young plantations were more likely to have retained populations of either fritillary species than woodlands with larger areas of mature conifer (data presented as model results). Butterfly records from six data sources were used to identify 52 woods which had contained fritillary populations since 1970. The area of four habitat types was mapped in each wood: established coppice cut within the last four years, young plantation on a previously wooded site, mature deciduous woodland and mature conifers. In 1990–1991, all but one of the woods were visited to record whether fritillary populations were still present.Study and other actions tested
Referenced paperClarke S.A. & Robertson P.A. (1993) The relative effects of woodland management and pheasant Phasianus colchicus predation on the survival of the pearl-bordered and small pearl-bordered fritillaries Boloria euphrosyne and B. selene in the south of England. Biological Conservation, 65, 199-203.
A replicated, site comparison study in 2002–2004 in a woodland in West Sussex, UK (Broome et al. 2011) found that coppiced woodland of different ages supported different moth communities. The moth community in young coppice (1–4 years old) was different from that in mid-aged coppice (5–8 years old), and both were different from old coppice (12–20 years old) (data presented as model results). No further statistical tests were conducted. Over three years, in young coppice, 109–256 individuals/trap and 20–31 species/trap were caught, compared to 100–218 individuals/trap and 26–27 species/trap in mid-aged coppice, and 186–342 individuals/trap and 28–44 species/trap in older coppice. Fifty-one species were only caught in young coppice, compared to 14 in mid-aged coppice, and 31 in old coppice. In 2003, the number of scarce species of conservation concern was 15–23 in young coppice, compared to 11–17 in mid-aged coppice, and 21–24 in old coppice. See paper for individual species results. A 200-ha sweet chestnut Castanea sativa wood was managed by coppicing 0.25–4 ha patches every 12–16 years. Eight patches, last cut between 1984–2001, were studied. In late June–early July 2002–2004, moths were surveyed on two nights/year using a 125 W mercury vapour ‘Robinson’ trap placed in the centre of each patch.Study and other actions tested
A replicated, site comparison study in 2010 in six deciduous woodlands in Hampshire and Wiltshire, UK (Merckx et al. 2012) found that coppiced woodland had a lower abundance and species richness of macro-moths than non-coppiced mature forest, but more unique species. Both the abundance and species richness of macro-moths were similar in young (1,248 individuals; 160 species), mid-age (1,433 individuals; 167 species) and old coppice (2,071 individuals; 162 species) and wide rides (1,926 individuals; 175 species), but were lower than in non-coppiced mature forest (2,479 individuals; 180 species) and standard rides (2,513 individuals; 176 species). However, coppiced woodland and wide rides supported 49 species not found in mature forest or standard rides, and 124 species were more abundant in coppiced woodland and wide rides than in mature forest and standard rides, especially ‘common but severely declining’ species (see paper for details). Only 22 species were found in mature forest or standard rides but not coppiced woodland or wide rides. Within six woodlands (8–711 ha), six areas under each of six management types were studied: young (1–2 years), medium (3–6 years) and old (7–9 years) coppice, wide (>20 m) and standard (<10 m) rides, and non-coppiced mature forest. All coppiced sites had been actively managed for at least 20 years. From July–October 2010, macro-moths were sampled nine times/site using a 6 W Heath actinic light trap, over 27 nights (two sites/management type sampled/night).Study and other actions tested
A replicated, site comparison study in 2010 in five woodlands in the Alsacian Hardt, France (Fartmann et al. 2013) found that recently coppiced woodland had a higher abundance and species richness of butterflies than older coppiced woodland, and that coppiced woodland of different ages had distinct groups of species. Two years after coppicing, woodland had a higher abundance and species richness of resident (abundance: 6 individuals/100 m2; richness: 11 species/plot) and threatened (abundance: 1.8 individuals/100 m2; richness: 4 species/plot) butterflies than woodland which had not been coppiced for >15 years (resident: 1 individual/100 m2; 4 species/plot; threatened: 0.2 individuals/100 m2; 1 species/plot). Coppiced woodland had a higher abundance of migratory butterflies one (1.2 individuals/100 m2) and two years (1.1 individuals/100 m2) after coppicing than >15 years after coppicing (0.2 individuals/100 m2). However, all five ages of coppiced plots held distinct groups of species (data presented as model results). Across five woodlands (140–1,303 ha), 37 coppiced plots (1–3 ha, 31–41-year coppice cycle) in one of five stages (first year, second year, 3–7 years, 8–15 years and >15 years after coppicing) were surveyed. From May–August 2010, butterflies were surveyed seven times in a 20 × 25 m area in the centre of each plot.Study and other actions tested
A replicated, before-and-after, site comparison study in 2000–2016 in 10 coppiced forests in Bavaria, Germany (Dolek et al. 2018) found that the number of webs of Eastern eggar moth Eriogaster catax and scarce fritillary Euphydryas maturna caterpillars was higher in recently coppiced woodland than in older woodland. Eastern eggar moth caterpillars were most often found in patches 5–10 years after the last coppice, and their abundance peaked after 5–7 years (data presented as model results). Scarce fritillary caterpillars were most often found in patches 10–12 years after the last coppice, and their abundance peaked after 12–15 years (data presented as model results). Coppicing commenced in 2005 at nine sites (23–310 ha), and in 2012 at a tenth site (80 ha) under a Government-funded scheme. From 2000–2016, caterpillars of Eastern eggar moth and scarce fritillary were surveyed in early May and late July–early August, respectively, by counting their silk-woven webs, in both coppiced and non-coppiced areas at each site. Each site was surveyed 0–5 times before coppicing (2000–2004) and 1–12 times after coppicing (2005–2016).Study and other actions tested