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Impact of muntjac deer (Muntiacus reevesi) at Monks Wood National Nature Reserve, Cambridgeshire, eastern England A.S. COOKE1 AND L. FARRELL2 1 13

Biggin Lane, Ramsey, Huntingdon, Cambridgeshire PE26 1NB, England Natural Heritage, 1 Kilmory Estate, Kilmory, Lochgilphead, Argyll PA31 9RR, Scotland

2 Scottish

Summary Muntjac deer (Muntiacus reevesi) were first reported at Monks Wood National Nature Reserve, Cambridgeshire, in the early 1970s. By 1985, they had had noticeable effects on coppice regrowth, principally of hazel (Corylus avellana), field maple (Acer campestre) and ash (Fraxinus excelsior). Despite trials of various protective measures, coppicing operations were suspended in the wood in 1995 because of browsing impact. Other woody vegetation had been heavily browsed and for some species abundance had been affected, e.g. bramble (Rubus fruticosus). Among the ground flora there have been effects on the vigour, reproduction and abundance of a range of common and rare species. Other plant species, such as some grasses and sedges, have increased because they are avoided by deer, are more tolerant of grazing or have benefited from changes in management. Invertebrates, in particular, may have been affected by these changes in plant composition with, for instance, increases being noted for lepidopteran species dependent on grasses.

Introduction Monks Wood is the largest wood in Cambridgeshire, extending to 157 ha. For centuries it had been managed traditionally as coppice-withstandards, but much of it was clear-felled at the end of the First World War (Steele and Welch, 1973; Massey and Welch, 1994). In 1953/54 it was purchased by the then Nature Conservancy (now English Nature) and established as a National Nature Reserve. The forest canopy is predominantly ash (Fraxinus excelsior) with pedunculate oak (Quercus robur); the shrub zone © Institute of Chartered Foresters, 2001

is diverse and includes hazel (Corylus avellana) and field maple (Acer campestre). Structural and habitat variety is enhanced by ponds, streams, rides and areas of grassland, and the wood supports rich assemblages of ground flora and invertebrates (Massey and Welch, 1994). It is classified as Fraxinus excelsior–Acer campestre–Mercurialis perennis woodland, community W8 (Rodwell, 1991). Monks Wood has the largest and densest population of muntjac (Muntiacus reevesi) so far documented in Britain (Cooke et al., 1996). Reasons for this situation include that the reserve is in a Forestry, Vol. 74, No. 3, 2001

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region that has been colonized by muntjac for many decades (Chapman et al., 1994), and until recently the deer population was not culled inside the wood. Large woods may also tend to have more extensive quiet areas compared with small woods, and therefore contain disproportionately high numbers of deer (Cooke, 1996; van Gaasbeek et al., 2000). By the mid-1980s, it became apparent to the woodland managers that deer were having unacceptable effects on coppice. Trials were initiated, first protecting cut stumps with brash, then fencing whole coppice coupes (Cooke, 1994a; Cooke and Lakhani, 1996). Further studies demonstrated that effects were not restricted to coppice, but extended more widely in the wood and to other organisms e.g. ground flora and invertebrates (Pollard and Cooke, 1994; Wells, 1994; Cooke et al., 1995; Cooke, 1997). Concerns raised by this work resulted in English Nature liaising with stalkers shooting outside the wood from the mid-1990s, then permitting shooting within the wood from 1998. The work has also helped to raise awareness of the effects of muntjac in woodlands, and has led to monitoring and management elsewhere (Cooke, 1996, 2001). This paper is a descriptive account of changes and effects in Monks Wood, drawing on published work and previously unpublished observations on coppice regrowth, semi-natural woody vegetation, ground vegetation and other fauna. It begins with a brief account of trends in the muntjac population.

Deer population trends From initial records in ~1970, numbers of muntjac increased until 1985 (Cooke, 1994a). Mean numbers counted per hour, based on 6–14 surveillance walks each January–May, 1986– 2000, are summarized in Figure 1. On average ~20 muntjac per hour could be seen up to 1998. In a separate investigation, counts in 1 ha plots along a transect in the summer of 1993 suggested a density of ~1.2 ha–1 (equivalent to a total population of ~190 muntjac; Cooke et al., 1996). Recent shooting within the wood has led to a decline in deer numbers. During 1998/99, 106 were shot inside and just outside the wood (P.

Figure 1. Mean number of muntjac seen in Monks Wood during dusk walks, January–May 1986–2000.

Green, personal communication); other muntjac have also been shot by stalkers not reporting back to English Nature. The effect of this cull was to reduce mean numbers seen from 17 per hour in 1998 to 6 per hour in 1999 (t18 = 4.96, P < 0.001; Figure 1). Using the mark-resighting technique described by Mayle et al. (1999) in a study area of 61 ha in the south of the wood, density was estimated to be 1.1 ha–1 in 1998 and 0.3–0.6 ha–1 in 1999. Other mammalian grazers and browsers occur and have also caused difficulties for the woodland managers, e.g. rabbits (Oryctolagus cuniculus) and brown hares (Lepus europaeus) hindered attempts to re-establish hazel in coppice areas (Massey, 1994a). In 1993/94, numbers recorded during 96 walks along an 8 km fixed route may roughly reflect the relative abundance of certain species: muntjac 2333, Chinese water deer (Hydropotes inermis) 13, roe deer (Capreolus capreolus) 2, rabbit 559 and brown hare 384 (Cooke et al., 1995). Through the late 1980s and early 1990s, muntjac will have been the predominant grazers and browsers listed above. The contribution from small mammals should not, however, be ignored (e.g. grazing on bluebells Hyacinthoides non-scripta; Cooke, 1997).

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I M PA C T O F M U N T J A C D E E R AT M O N K S W O O D

Coppice regrowth Until 1914, the wood was actively coppiced on a 20-year rotation, with the standards also being harvested (Hooper, 1973). Since the 1950s, 12.7 ha distributed across 17 sub-compartments have been returned to coppice on a rotation of 10 years, and the shrub zone beside major rides has also been cut to diversify habitat (Massey, 1994a). From 1987, regrowth was protected against browsing by muntjac, first by brash piles on the stumps, then by electric fencing (Cooke, 1994a; Cooke and Lakhani, 1996). More recently, rideside clearance has been protected with metal, wire-mesh or plastic fencing. Muntjac are small deer and mainly browse regrowth stems up to a height of 100 cm (Cooke and Farrell, 1995). Stems that are taller may be bitten at a convenient height and broken so that their tips can be defoliated (Cooke and Farrell, 1995). Although less commonly encountered than direct browsing, breakage often causes loss of leading regrowth stems. Stems are usually safe from breakage once they have attained a thickness of 1 cm at a height of 1 m. It has been observed that slow-growing species, e.g. dogwood (Cornus sanguinea), are usually more damaged by direct browsing during the first growing season than species with rapid growth, such as willow (Salix spp.; Cooke, 1994a). Similarly, slower-growing individuals of a single species are more likely to be seriously damaged (Cooke and Farrell, 1995). Browsing of regrowth does not always lead to significant ecological or conservation impact. At the level of an individual stool, browsing may have negligible effect on the final canopy after regrowth, it may reduce the canopy density perceptibly (Cooke and Farrell, 1995), or, if all regrowth is destroyed and browsing continues, the stool is likely to die within a few years (Cooke, 1998a). Depending on the conservation objectives, reductions in canopy density at coupe level may be unacceptable to managers because of effects on vegetation succession. Acceptability of browsing can be determined in several ways such as by visual assessment (Cooke, 1994a) or by counting stems reaching canopy height per unit area or per stool (Cooke and Lakhani, 1996). The final decision involves a value judgement, comparing aims and observations.

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Visual assessment for the four principal coppice coupes cut between 1985 and 1988 indicated failure in 1985 and 1986 when they were unprotected against muntjac, but marginal acceptability in 1987 and 1988 when brash piles were used, although the high density of standard trees may have caused shading problems (Cooke, 1994a; Massey, 1994b). Counting canopy stems per unit area in nine coupes that had been cut between 1989 and 1993 and protected with electric fences revealed that two had failed, one was poor and unacceptable, while six were acceptable. However, one of the last group had suffered a browsing-mediated shift in the composition of the canopy towards birch (Betula spp.) and away from hazel and ash (Cooke, 1994a; Cooke and Lakhani, 1996). Damage had resulted because the electric fences failed to prevent access by deer, especially in quiet areas of the wood. In contrast, if coupes were adjacent to major rides, then damage was relatively slight. Within fenced and unfenced study plots, browsing was positively related to dung counts in the summer months (Cooke and Lakhani, 1996). Deer and dung counts were also related to one another, and it was calculated that if the deer population was reduced by 90 per cent then coppice regrowth would not need fencing (Cooke and Lakhani, 1996). Such action in isolation was considered impractical. An alternative suggestion by Putman (1996) was to erect a fence around the main area of coppice (6.1 ha), where four of the seven coupes had failed because of deer browsing, the last being cut in 1994. In 1999, deer fencing was erected around the perimeter of the main coppice block, and a second fence was erected around 10.6 ha in the south-west corner of the wood, where three other coppice coupes occurred. The effects of these fences are being monitored.

Semi-natural woody vegetation In contrast to coppice regrowth, which was acknowledged as being damaged by deer as early as 1985, relatively little was known until recently about possible effects on semi-natural woody vegetation. Peterken (1994) resurveyed in 1992 part of a transect previously recorded in 1985 and noted that the most obvious change was the

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destruction of privet (Ligustrum vulgare) undergrowth and groups of ash regeneration. He commented that privet had exceeded 1.3 m in 1985, but was 20 cm with a mean number of plants of 4.5 ± 2.0 (significantly different from controls, Mann–Whitney U4,4 = 0, P < 0.05). A check of the control plots in 1998 showed that one out of eight had a single hawthorn (Crataegus monogyna) >20 cm in the centre 2 2 m. It seemed that such survival and growth was not possible till coarse grasses provided sufficient protection from browsing. In 1997, mean numbers of seedlings or frequency of bramble, privet and honeysuckle were higher inside the fences in all cases except one. However, only for hawthorn in 19a was the difference significant (paired t3 = 5.00, P < 0.05). Significantly better growth was found in fenced plots for privet and bramble in compartment 27c and for hawthorn, honeysuckle and bramble in 19a (Friedman’s test on mean height change per annum, P < 0.05; see Figure 2 for a typical example). Although there was little or no growth in the control plots, these species continued to grow throughout the experiment inside the fences.

Ground vegetation Species directly affected by grazing Muntjac have ready access to ground vegetation whereas they can only take woody vegetation that is within their reach. They appear to relish certain species of ground flora, but avoid others, so some species are directly affected while others may

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Figure 2. Mean height attained by bramble inside four exclosures in compartment 19a (unshaded bars) and in four unfenced control plots (shaded bars).

benefit indirectly. In some cases, the former species have been relatively rarely eaten in the past by wild mammals or livestock, and are intolerant of grazing. It took several years before it was appreciated that the ground flora was changing. Work on lady’s smock (Cardamine pratensis) revealed an increase in the level of grazed flowers from 1986 (Cooke, 1994a; Dempster, 1997). However, changes in abundance of rare species (e.g. herb Paris Paris quadrifolia, early purple orchid Orchis mascula and greater butterfly orchid Plantanthera chlorantha) and widespread species (e.g. primrose Primula vulgaris, violet Viola spp., bluebell and wood anemone Anemone nemorosa) were reported at the Monks Wood Symposium in 1993 (Massey, 1994a; Wells, 1994). Deer grazing was suggested as a probable cause, although aerial enrichment with nitrogen compounds and changes in management were also discussed. At the same time, studies on the direct effects of grazing on certain species were beginning (Cooke, 1994a), among them bluebell, dog’s mercury (Mercurialis perennis) and lords and ladies (Arum maculatum). Grazing on bluebell inflorescences is readily apparent each spring (Cooke, 1994a, 1997). In addition, earlier grazing of leaves reduces vigour, the plants having shorter leaves (Cooke, 1997) and shorter inflorescences with fewer flowers (T. Sparks, personal communication). Information on changes in abundance is, however, conflicting

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(Wells, 1994; Cooke, 1997; Crampton et al., 1998). Cooke (1997) observed that bluebells inside the exclosures erected in 1993 had shown a partial, but significant, recovery in leaf length by 1995. These bluebells did not recover further; in 1998 the leaves were intermediate in length between controls outside the exclosures and leaves in situations with little or no deer grazing. While it is possible that plants may not recover totally from such a change, in some years up to 30 per cent of the leaves inside the exclosures were grazed, presumably by small mammals. Since 1993/94, bluebells have been monitored by means of fixed 0.5 m quadrats in several localities in the wood, including a dense stand in the woodland compartment 27f (Figure 3). Total numbers of inflorescences and numbers grazed varied from year to year, but the latter was particularly low in 1999, associated with reduced deer numbers (Figure 1). Leaf length recovered significantly in 1999 (t18 = 2.39, P < 0.05). Dog’s mercury is heavily grazed and, except in exclosures, is reduced considerably in size because of grazing (Cooke et al., 1995; T. Sparks, personal communication). Unlike bluebells, there is good evidence of a marked decline in abundance since the 1970s (Cooke et al., 1995 and unpublished). Lords and ladies is toxic to stock, but is also grazed by muntjac (Diaz and Burton, 1996). In Monks Wood, >50 per cent of inflorescences have been recorded as being grazed, there has been a low ratio of seedlings to mature plants, and reproduction has been affected as there is a reduced chance of setting seed (Diaz and Burton, 1996). That these three well-studied species have been affected directly by muntjac is beyond reasonable doubt, but other factors cannot be totally ignored. Putman (1996) suggested that increased competition from vigorous grasses and sedges may exacerbate any loss from coppice areas. While early losses in coppice areas may not be associated with increased grass growth, an example from compartment 27c is given in Figure 3 of a decline in bluebell inflorescences over a period of several years; the coppice canopy was patchy where the bluebells were recorded and their decline may have been related to growth of grasses and sedges, as well as to shading by the canopy. This coppice coupe has had higher deer

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activity than the woodland area (27f), and this is reflected in the higher levels of grazing damage and consistently shorter leaves. Cooke (1996, 1997, 2001) described a technique with ivy stems inserted into the ground to measure feeding activity of muntjac. Ivy trials have demonstrated a reduction in feeding activity in Monks Wood following the cull in 1998/99 as the browse level after one day dropped significantly from 82 per cent in 1997 to 25 per cent in 1999 (t8 = 2.57, P < 0.05), so providing further confirmation of the recent improvement in the wood. Generally, muntjac are considered to cause little damage to agricultural interests. They do, however, forage outside the wood and there have been several instances when crops close to the reserve have been affected by grazing. The most serious case occurred in the winter of 1997/98 through to the summer of 1998 on two fields to the east. Crops of field beans were growing in both fields, which have a combined area of ~29 ha and a shared boundary of ~770 m with the wood. A mown grass strip runs down the entire western edge of the fields to provide the deer with an open area to cross and to make it easier to shoot them. The deer had eaten the shoots, leaves and pods, and breakage was used to bring down growing tips. Transects into the fields at 50 m intervals and perpendicular to the wood boundary revealed that plant height was affected in the northern field to 70 m and in the southern field to 45 m. Pod length and number of pods per plant were both positively related to plant height (Spearman rank correlation coefficient, n = 18, P < 0.05), so it may be reasonable to assume that yield was reduced along the field edges. Species that have increased

Figure 3. Information on bluebells in woodland (compartment 27f, shaded bars) and in a coppice area (compartment 27c, unshaded bars) showing (a) mean number of inflorescences per 0.5 m quadrat, 1993–1999, (b) mean number grazed per quadrat and (c) mean leaf length, 1994–1999.

Other species may benefit because their unpalatability or tolerance of grazing gives them an advantage over grazing-sensitive species or allows them to flourish in an enriched environment (e.g. see Putman, 1998). While most seem to be grasses or sedges, a few are dicotyledonous species e.g. ground ivy (Glechoma hederacea; Cooke et al., 1995; Crampton et al., 1998) and spurge laurel (Daphne laureola; van Gaasbeek et al., 2000). Ground ivy is toxic to livestock (Cooper and Johnson, 1984), and has a smell which we regard

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as characteristic and strongly pungent. Muntjac tend to avoid areas dominated by ground ivy. Deer were counted in twenty 0.5 ha woodland plots bordering rides, four times each month at midday and four times at dusk from May 1993 to April 1994; ground ivy was the dominant summer/autumn vegetation in 10 of the plots, but not in the others. Significantly fewer deer were recorded in the plots dominated by ground ivy during July–August, both at midday and at dusk (Poisson regression analysis, P < 0.001; see Figure 4 for dusk), September–October (dusk, P < 0.05) and November–December (day, P < 0.01). Density of other ground vegetation made no difference to numbers of deer seen.

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deer grazing is unclear. Dense stands of pendulous sedge have quickly become established in wet parts of the wood where coppicing has failed to produce an adequate canopy because of deer browsing. Inside the 1978 exclosures, which contain a profusion of species that have declined in grazed areas, the grasses are less abundant (Cooke et al., 1995). Inside those exclosures breached in the late 1990s, grasses have now become dominant. Management on the rides or in the fields, for instance, will also have been conducive to encouraging the spread of grasses (Wells, 1994). Aerial enrichment of nitrogen compounds has not been studied in this locality, but amounts deposited may benefit certain monocotyledonous species in particular (Wells, 1994; Pollard et al., 1998).

Fauna

Figure 4. Cumulative number of muntjac counted at dusk, May 1993–April 1994, in 10 woodland plots dominated by ground ivy (shaded bars) and 10 plots not dominated by ground ivy (unshaded). Significant differences were noted for July–August (P < 0.001) and for September–October (P < 0.05).

The following species of grasses and sedges have been reported as increasing in the wood in recent years: wood small-reed (Calamagrostis epigejos), false-brome (Brachypodium sylvaticum), tufted hair-grass (Deschampsia cespitosa), rough meadow grass (Poa trivialis), pendulous sedge (Carex pendula) and pale sedge (Carex pallescens; Wells, 1994; Cooke et al., 1995; Crampton et al., 1998; Pollard et al., 1998). Increased abundance has been noted for certain of these species in a range of habitats in the wood: on rides, in the open fields, in failed coppice and in the woodland blocks. The role of

If muntjac have an effect on other fauna, it will be via changes to vegetation and habitat needed as food, shelter, nest sites, etc. These effects are not necessarily detrimental. The vegetation changes described above were most marked for coppice regrowth, ground vegetation and the shrub layer. This section considers the implications for several species of conservation interest. For some species, little or no change has been noted in recent years, e.g. the crested newt (Triturus cristatus; Cooke, 1994b and unpublished) and brown hare (unpublished). Chinese water deer, however, were first confirmed in the wood in the 1970s, but declined from the late 1980s (Figure 5; mean number per hour tested against year 1986–2000, Spearman rank correlation coefficient = –0.85, n = 15, P < 0.01). This decline occurred during the period when the muntjac population was highest (Cooke, 1994a). Decreases in water deer numbers have occurred in other local reserves as muntjac populations increased (Cooke, 1998b; Cooke and Farrell, 1995). Both species require bramble for autumn and winter forage, but the bramble thickets in Monks Wood have disappeared. Periodic die-offs of muntjac in Monks Wood (Cooke et al., 1996) suggest suboptimal amounts of food in winter, and this may be the reason for the current rarity of water deer.

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Figure 5. Mean number of Chinese water deer seen in Monks Wood during dusk walks, January–May 1986–2000.

The nightingale (Luscinia megarhynchos) typically prefers dense vegetation to heights of 3 m, and concern has been expressed that deer browsing of coppice regrowth or of the shrub layer can render habitat unsuitable (e.g. Fuller et al., 1999; Fuller, 2001). Unfortunately there is a recording gap from 1982 to 1987 inclusive in the numbers of singing males in Monks Wood. From the data available and from the more complete records at the nearby reserves at Woodwalton Fen and Holme Fen, numbers probably reached a peak in the mid-1980s. Numbers for comparable periods are assembled in Table 1 for the three reserves. In isolation, the data for Monks Wood suggest a decline in nightingale numbers that may be Table 1: Mean numbers (± SE) of singing male nightingales in Monks Wood and two other National Nature Reserves in Cambridgeshire in 1976–1981 when muntjac were colonizing and in 1988–1996 when they were established Reserve

1976–1981

1988–1996

Monks Wood Woodwalton Fen Holme Fen

11.2 ± 1.6 (6) 26.7 ± 3.5 (6) 28.3 ± 0.9 (6)

7.0 ± 0.7 (9)* 14.5 ± 2.7 (8)* 12.1 ± 4.0 (9)**

Number of years covered is given in brackets. *t test compared with the early period, P < 0.05; **P < 0.01.

related to coppice and shrub layer browsing by muntjac. However, when the data for the three reserves are considered collectively, they are less convincing. Nightingales seem to have shown temporally similar changes in all three reserves, indicating that common factors were operating, but when the declines started in Holme Fen and Woodwalton Fen in the late 1980s, muntjac were still comparatively rare there. Monks Wood has had the densest deer population and the most marked effects on vegetation damage, yet the decline in nightingales is marginally greater in the other reserves. It is difficult to believe that the more robust habitats of Woodwalton Fen were being sufficiently damaged in the late 1980s to produce such an effect. Nevertheless, the impact on coppice regrowth and the shrub layer since the mid-1980s cannot have been beneficial to nightingales in Monks Wood. Invertebrates that are dependent on specific plants would seem to be at particular risk. Deer browsing on low shrubs, such as bramble, has resulted in their loss, whereas browsing on higher-growing species, e.g. honeysuckle, has caused marked browselines. The white admiral butterfly (Ladoga camilla) tends to lay its eggs low down on honeysuckle, and Pollard and Cooke (1994) showed that potential and actual egg-laying sites had been lost by deer browsing. The white admiral population declined in Monks Wood, but the decline was no worse than elsewhere. Thus, although the butterfly’s behaviour was affected, the deer had no additional adverse effect on population level. In view of the increase in grass species in the wood, Pollard et al. (1998) examined whether lepidopteran species dependent on grasses had fared better. They found that four out of 18 species of butterfly had increased in Monks Wood since the 1970s and all had grass-feeding larvae. Three of these species, the large skipper (Ochlodes venata), speckled wood (Pararge aegeria) and ringlet (Aphantopus hyperantus), increased significantly relative to other sites in eastern England. The grass-feeding group of moths had similarly fared better than other moth species. As noted above, the role of deer grazing on the spread of grasses in the wood requires elucidation.

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Future research and monitoring Specific items of research that are needed include studying the effects of aerial inputs of nitrogen compounds and other factors on the spread of monocotyledonous species in the wood; and the status of small mammals and their role as grazers and browsers. Monitoring of the deer and their effects is essential as the population is controlled and vegetation recovers within the large new exclosures; for instance, will the flora recover fully and what will happen to bramble in the presence of limited or no browsing? It is to be hoped that managers of other woodlands will continue to learn from the case of Monks Wood how to recognize problems associated with muntjac and what to do about them. Many conservation woodlands require protection of coppice to try to prevent unacceptable levels of damage (Cooke, 1996; Putman, 1998). Coppice in Monks Wood has been considerably affected, apparently by a muntjac density of 1 ha–1 or more. If muntjac density could ever be reduced to ~0.1 ha–1 then coppice in Monks Wood should not require protection (Cooke and Lakhani, 1996). While densities above this level might be associated with unacceptable damage to regrowth, it does not necessarily follow that such a statement could be applied to other woodland situations, as damage might depend on factors such as amounts and spatial arrangement of coppice and alternative food resources. Cooke (1996, 2001) has advocated the prior use of ivy trials and ‘scoring’ to determine whether new coppicing management in a wood might lead to unacceptable impact. Marked changes to ground flora are much less commonly encountered than serious impacts on coppice and seem to be confined to woods with muntjac densities approaching those at Monks Wood, but this requires further work. Harris et al. (1995) suggested that 0.3 ha–1 is a typical density of adult muntjac in prime habitat, i.e. equivalent to ~0.45 deer ha–1 when juveniles and immatures are included. While a density of this magnitude is likely to cause concerns for the survival of coppice regrowth, it may not be associated with significant effects on flora. Whether such a deer density might detrimentally affect the shrub layer in a wood is not yet clear,

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but examination of bramble for winter browselines or die-back should provide a clue. Acknowledgements We thank T. Sparks for statistical advice and the Reserve staff for their help and interest.

References Chapman, N., Harris, S. and Stanford, A. 1994 Reeves’ muntjac Muntiacus reevesi in Britain: their history, spread and habitat selection, and the role of human intervention in accelerating their dispersal. Mammal Rev. 24, 113–160. Cooke, A.S. 1994a Colonisation by muntjac deer Muntiacus reevesi and their impact on vegetation. In Monks Wood National Nature Reserve: The Experience of 40 Years 1953–93. M.E. Massey and R.C. Welch (eds). English Nature, Peterborough, pp. 45–61. Cooke, A.S. 1994b Fluctuations in night counts of crested newts at eight breeding sites in Huntingdonshire 1986–1993. In Conservation and Management of Great Crested Newts. A. Gent and R. Bray (eds). English Nature, Peterborough, pp. 68–70. Cooke, A.S. 1996 Conservation, muntjac deer and woodland reserve management. J. Pract. Ecol. Conserv. Spec. Pub. 1, 43–52. Cooke, A.S. 1997 Effects of grazing by muntjac (Muntiacus reevesi) on bluebells (Hyacinthoides nonscripta) and a field technique for assessing feeding activity. J. Zool. Lond. 242, 365–369. Cooke, A.S. 1998a Survival and regrowth performance of coppiced ash (Fraxinus excelsior) in relation to browsing damage by muntjac deer (Muntiacus reevesi). Q. J. For. 92, 286–290. Cooke, A.S. 1998b Colonisation of Holme Fen National Nature Reserve by Chinese water deer and muntjac, 1976–1997. Deer 10, 414–416. Cooke, A.S. 2001 Information on muntjac from studying ivy. Deer 11, 498–500. Cooke, A.S. and Farrell, L. 1995 Establishment and impact of muntjac (Muntiacus reevesi) on two National Nature Reserves. In Muntjac Deer: Their Biology, Impact and Management in Britain. B.A. Mayle (ed.). Forestry Commission, Farnham and British Deer Society, Trentham, 48–62. Cooke, A.S. and Lakhani, K. 1996 Damage to coppice regrowth by muntjac deer Muntiacus reevesi and protection with electric fencing. Biol. Conserv. 75, 231–238. Cooke, A.S., Farrell, L., Kirby, K.J. and Thomas, R.C.

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1995 Changes in abundance and size of dog’s mercury apparently associated with grazing by muntjac. Deer 9, 429–433. Cooke, A.S., Green, P. and Chapman, N.G. 1996 Mortality in a feral population of muntjac Muntiacus reevesi in England. Acta Theriol. 41, 277–286. Cooper, M.R. and Johnson, A.W. 1984 Poisonous Plants in Britain and their Effects on Animals and Man. MAFF Reference Book 161. HMSO, London. Crampton, A.B., Stutter, O., Kirby, K.J. and Welch, R.C. 1998 Changes in the composition of Monks Wood National Nature Reserve (Cambridgeshire, UK) 1964–1996. Arboricult. J. 22, 229–245. Dempster, J.P. 1997 The role of larval food resources and adult movement in the population dynamics of the orange-tip butterfly (Anthocaris cardamines). Oecologia 111, 549–556. Diaz, A. and Burton, R.J. 1996 Muntjac and lords and ladies. Deer 10, 14–19. Fuller, R.J. 2001 Responses of woodland birds to increasing numbers of deer: a review of evidence and mechanisms. Forestry 74, 289–298. Fuller, R.J., Henderson, A.C.B. and Wilson, A.M. 1999 The nightingale in England – problems and prospects. Br. Wildl. 10, 221–230. Harris, S., Morris, P., Wray, S. and Yalden, D. 1995 A Review of British Mammals. JNCC, Peterborough. Hooper, M.D. 1973 History. In Monks Wood: A Nature Reserve Record. R.C. Steele and R.C. Welch (eds). Nature Conservancy, Huntingdon, pp. 22–35. Massey, M.E. 1994a Managed change. In Monks Wood National Nature Reserve: The Experience of 40 Years 1953–93. M.E. Massey and R.C. Welch (eds). English Nature, Peterborough, pp. 13–17. Massey, M.E. 1994b Changes in management policies. In Monks Wood National Nature Reserve: The Experience of 40 Years 1953–93. M.E. Massey and R.C. Welch (eds). English Nature, Peterborough, pp. 69–73. Massey, M.E. and Welch, R.C. (eds) 1994 Monks Wood

National Nature Reserve: The Experience of 40 Years 1953–93. English Nature, Peterborough. Mayle, B.A., Peace, A.J. and Gill, R.M.A. 1999 How Many Deer? Forestry Commission, Edinburgh. Peterken, G.F. 1994 Natural change in unmanaged stands within Monks Wood NNR. In Monks Wood National Nature Reserve: The Experience of 40 Years 1953–93. M.E. Massey and R.C. Welch (eds). English Nature, Peterborough, pp. 1–8. Pollard, E. and Cooke, A.S. 1994 Impact of muntjac deer Muntiacus reevesi on egg-laying sites of the white admiral butterfly Ladoga camilla in a Cambridgeshire wood. Biol. Conserv. 70, 189–191. Pollard, E., Woiwod, I.P., Greatorex-Davies, J.N., Yates, T.J. and Welch, R.C. 1998 The spread of coarse grasses and changes in numbers of Lepidoptera in a woodland nature reserve. Biol. Conserv. 84, 17–24. Putman, R.J. 1996 Deer Management on National Nature Reserves: Problems and Practices. Research Report 173. English Nature, Peterborough. Putman, R.J. 1998 Deer impact on conservation vegetation in England and Wales. In Population Ecology, Management and Welfare of Deer. C.R. Goldspink, S. King and R.J. Putman (eds). Manchester Metropolitan University, Manchester, pp. 61–66. Rodwell, J.S. (ed.) 1991 British Plant Communities: 1 Woodland and Scrub. Cambridge University Press, Cambridge. Steele, R.C. and Welch, R.C. (eds) 1973 Monks Wood: A Nature Reserve Record. Nature Conservancy, Huntingdon. van Gaasbeek, F., Waasdorp, D. and Sparks T. 2000 The status of Primula and Daphne laureola in Monks Wood NNR in 1999. Huntingdon Fauna Flora Soc. Rep. 1999 52, 8–12. Wells, T.C.E. 1994 Changes in vegetation and flora. In Monks Wood National Nature Reserve: The Experience of 40 Years 1953–93. M.E. Massey and R.C. Welch (eds). English Nature, Peterborough, pp. 19–28.