Hedges Cardigan

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A Survey of Hedges and their Woody Species in Mid-Wales

A.T.Jones and A.O.Chater*

The Jordans, Mill Hill, Brockweir, Chepstow NP16 7NW.

*Pen Yr Anchor, Aberystwyth, Ceredigion

Summary

(1) A survey of the woody species and physical attributes of 2223 hedge sample lengths from 752

individual hedges in Ceredigion, mid-Wales was made between 1974 and 1979. Most hedges

occurred on banks. Although 56% of the hedges were dense and impenetrable, the remainder

needed at least some renovation; only 39% had clearly been managed in the previous decade.

Hedges along lanes were in the best condition; the condition of hedges and the proportion managed

declined significantly with altitude.

(2) A tentative grouping of hedges by woody species based on ordination analysis is as follows: 1,

common planted species only; 2, typically unplanted and moisture loving species; 3, gappy hedges

with Ulex europea and Vaccinium myrtillus; 4, hedges with Fagus sylvatica.

(3) Hedge species diversity was positively related to (i) presence of semi-natural habitats e.g.

marshy grassland, (ii) aspect, e.g. north facing slopes, unrelated to (i) age, (ii) length, (iii) altitude

and negatively related to (i) presence of dominance species, (ii) poor condition.


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(4) Hedges on marshy ground had the highest species diversity and a higher frequency of native

woodland species than hedges adjacent only to pasture and\or lanes; marshy ground also had the

highest proportion of old hedges.

(5) For each species the species diversity of hedge samples where it was present was calculated. For

colonist and common planted species, mean hedge species diversity was lower than for rarer

species typical of native woodland.

(6) There were differences between species in the relationship between their physical dominance of

hedge samples and hedge species diversity. Diversity was much lower in hedges where dominance

was exhibited relative to hedges where it was not for colonist and common planted species than for

woodland species.

(7) Hedges in Ceredigion were more diverse than in lowland England. Key words: diversity,

dominance, hedge-dereliction, shrubs, trees.

Keywords: hedge, landscape, woody, diversity, land-use

Introduction

Hedges are a widespread linear landscape feature in north-west Europe, including the UK, Eire andFrance (Brittany and Normandy in particular) and the eastern USA of interlocking shrubs and trees

arranged along field-boundaries. They also occur as field boundary features in tropical areas

including the Caribbean, but the term is also used to describe cropping systems. Their original

primary function has been to form a barrier to livestock and in northern Europe and there is


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evidence of their deliberate planting and management since at least Roman times (Caesar, 55). They

can also be casual formations as is often the case in the USA (Forman, 1995) growing up alongside

fence-lines in the area that escapes ploughing. Another class of hedge, termed an assart, has been

created over many century and possibly millennia from the gradual encroachment into woodlands

on two sides, with a strip of the original cover left to define a boundary (Pollard, Hooper and Moore

1974). In terms of habitat, hedges are often considered akin to scrub rather than woodland

depending on prevailing levels of grazing and hedgerow management which can maintain a

juvenile phase as a plagioclimax. Under the UK system of vegetation habitat classification, they are

described within scrub, e.g. Crataegus monogyna-Hedera helix scrub community (Rodwell et al,

1991). As many can be dated accurately from records, hedge can be considered living experiments

in a range of processes which may determine woody species diversity including dispersal of seed

and pollen through their lattice like arrangement, colonization and competitive ability.

From surveying 30m hedge sample lengths, Hooper (1970) found that hedges with the greatest

diversity of woody plant species were often some of the oldest when dated with parish and estate

records. This led to Hooper's hedgerow hypothesis (Pollard, Hooper and Moore 1974) which

proposes that hedges `collect' new species through a process of colonization over time (and also the

possibility that older hedges represent assarts). Thus a pure Crataegus monogyna (hawthorn) hedge

established during the enclosures around the 18th century could eventually consist of a mixture of

species. The relationship between hedge diversity and age was summarised in a linear model based

on hedges sampled from a large area of lowland England. This species number age relationship hasbeen compared by Cameron and Pannett (1980) for hedges in Shropshire and Willmot (1980) for

Derbyshire hedges and only in the latter was a significant positive relationship found.


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Surveys of hedges in mid-Wales were carried out in the growing season between the years of 1974

and 1979 to examine the applicability of Hooper's linear model there. In a preliminary analysis

(Chater 1985; 1993) Hooper`s hedgerow hypothesis was not found to be supported in the area

sampled. In fact the converse held, with older hedges being poorer in woody species than

demonstrably younger ones.

The hedge data set contained much more information, allowing in particular the relationship

between the following physical and ecological factors and hedge species richness and composition

to be examined:

1. Management and condition

2. Altitude and aspect

3. Hedge length

4. Adjoining land-use

5. Species interaction and competition

It is also possible to determine the broad ecological niche requirements of a range of hedge species

in terms of their association in the form of hedge communities.


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Methods

Hedge Survey

Between April 1974 and July 1979, a total of 2223 samples were surveyed from a total of 752

hedges in the Ceredigion district of mid-Wales, a geographical area extending from the Dyfi estuary

to the Teifi (Figure 1). The total length of samples surveyed was 66.7km. Each sample comprised a

30m length of hedge, in which all the woody species were recorded together with a wide range of

physical and in many cases historical data (Table 1).

Hedges were chosen for sampling in some cases because they were in areas where estate maps and

other documentary evidence enabled the hedges to be dated; in such cases every hedge in the area

was sampled. In other cases hedges were chosen because they were on parish or property

boundaries or seemed otherwise to be of historical interest. Many more were chosen to include as

wide a range as possible of hedge types within the district. The survey in all probability gives a

reasonable picture of the character of hedges in Ceredigion. To determine sample lengths, a new

hedge was taken to start wherever a junction with another hedge occurs, or where a hedge abruptly

changes direction.

Existing management refers to that management which from observation of the hedge has taken

place in the last decade. Previous management refers to evidence of management which had taken

place more than a decade previously and may be indicated by signs of former laying, often of

substantial laid tree-stools of considerable age. The traditional methods of hedge management inCeredigion have been described by Scourfield (1977).

The condition of each hedge was assessed in relation to the measures which would be needed for its

renovation.


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Dating of hedges

Dating of hedges was done from manuscript estate maps and also from parish tithe maps of the

1840`s in the National Library of Wales, and from Ordnance Survey maps at 6 inch/mile and 25

inch/mile scales for the 1885, 1887 and 1905 editions.

Results

Hedge species richness in relation to condition and management

Hedge samples in poor condition showed lower diversity than those in good condition (Table 2).

Using Cochranes approximate t-test (Snedecor and Cochrane, 1980), diversity was found to be

significantly different (probability < 0.05) between all pairs of condition categories. Variance in

diversity was much greater for the poor hedge condition categories despite these representing

smaller samples. Most species were less frequent in the poor hedge condition categories (2-4)

compared with hedge samples in good condition (1). Vaccinium myrtillus,Betula pendula and Ulex

europea were significantly more frequent in hedge samples in condition category 3, i.e. hedges

needing intensive renovation. The light demanding heathland species, Calluna vulgaris and Ulex

gallii were also significantly more frequent in this category.Betula pubescens andAlnus glutinosa

(the later only of borderline significance) were most frequent in hedge samples of condition

category 4, i.e. those hedges grown up to a line of trees.

Sambucus nigra which is often considered an indicator of poor hedge management showed in thissurvey the same pattern of lower frequencies in poor hedges as most other species.

There was a highly significant Chi-square association (P < 0.001) between poor condition, i.e.

increasing gappiness, and lack of management in the hedges sampled.


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Hedge species richness and altitude

There was no significant relationship between hedges species diversity and altitude using regression

analysis, species diversity being highly variable at all altitudes, and the correlation coefficient being

-0.212. When we consider, however, only the poorer hedges with 3 or less species which were

surveyed (which accounted for 5% of all the hedges), 85% occurred above 180m.

Many species showed differences in frequency at different altitudes. Most species (Table 12),

including the hedge dominants and climbers, Corylus avellana, Prunus spinosa, Lonicera

periclymenum and Hedera helix declined in frequency as hedge altitude increased. Crataegus

monogyna was exceptional amongst species in being equally frequent (C90%) at all altitudes and

even above 240m. Some species which were rare or absent at lower altitudes were frequent in

hedges above 240m, notably Vaccinium myrtillus, Sorbus aucuparia, Rubus idaeus and Cytisus

scoparius. Fagus sylvatica, the most widely planted species that is not native in the study area, was

most frequent above 240m, probably because it was planted more for shelter than for stockproofing

(Chater 1985).

The percentage of dense hedges declined significantly from 64% below 60m in altitude to 21.6%

above 240m (Table 3). The percentage of recently managed hedges also declined significantly from

64.1% below 60m to 12.1% above 240m.

Species richness and hedge aspect

The Ceredigion area consists of a plateau dissected by deep valleys and there must be considerabledifferences in microclimate including humidity, temperature and soil moisture between north and

south facing slopes which may affect hedges. Hedges on north-facing slopes (including north-east

and north-west facing slopes) were, therefore, compared with those on south-facing slopes

(including south-east and south-west slopes).


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There was a significant difference in species diversity between the two different hedge aspect

classes, with north-facing hedges having more species (Table 4). Several species were significantly

more frequent on north facing slopes, most notably Vaccinium myrtillus, Quercus petraea and

Sorbus aucuparia but no species showed higher frequency on south-facing slopes.

Species richness and hedge length

The species diversity of a particular hedge may be dependant on its length (which is related to field

size and hedge density) as proximity to other hedges across fields and differences in distances to

hedge junctions will affect dispersal distances involved in the colonization process (Baudry 1984;

Baudy 1987). There will be smaller dispersal distances to shorter hedges and they may, therefore,

be expected to have more species than the mean.

To examine this relationship hedge length and diversity was analyzed by regression for the hedge

samples. There was, however, no significant relationship between hedge length and diversity, the

correlation coefficient being -0.021. Four species, however, showed significant differences in

frequencies between hedges below and above 120m in length. Alnus glutinosa and Salix aurita

were significantly more frequent in hedges below 120m in length andLonicera periclymenum and

Vaccinium myrtillus in hedges above this length.

Hedge species richness and hedge land-use category

The hedges were classified into 23 categories according to land-use combinations found on either

side of them. Most hedges (94%), however, occur in six categories (Table 1). The commonesthedge category was lanes\pasture, accounting for 50% of the samples. Hedges with pasture on both

sides accounted for 30% and the remainder were mainly arable\lanes (2%), stream\pasture (2.5%),

pastures\marshy pastures (7%) or marshy pastures on both sides (2.4%). Hedges bordering

woodland were rare and have not been included in analyses but are described later in the text.


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Of the major land-use categories, diversity of species was greatest (Table 5a) in hedge samples on

marshy ground on one or both sides, i.e. marsh/pasture and marsh/marsh, followed by hedge

samples adjacent to lanes, i.e. lane/pasture and lane/arable. Pasture/pasture and stream/pasture

hedge samples had the lowest numbers of species. However, a subset of a pasture/pasture hedges

with ditches had a high diversity and were similar to marsh hedges. Diversity was significantly

different between marsh hedges and other hedges using Cochrans approximate t-test (Snedecor and

Cochrane 1980) for unequal variances (Table 5b). Marsh hedges were distinctive in having the

lowest frequencies of those species that are often planted e.g. Crataegus monogyna and Prunus

spinosa and highest frequency of unplanted species and those commonly forming natural plant

communities e.g. Salix aurita,Betula pubescens and Sorbus aucuparia.

Those hedges bordering woodland were rare and together represented approximately 2% of

samples. Two hedge categories, lane/deciduous woodland and pasture/ deciduous woodland both

had 22 samples and had a mean species diversity of 8.56 and 8.41 respectively. Marshy

pastures/deciduous woodland hedge samples with only 6 samples had a mean of 11.83 species. In

this later category Corylus avellana andAlnus glutinosa were frequent where Crataegus monogyna

and Prunus spinosa were more frequent in the previous two woodland categories. It appears,

therefore, that hedge samples adjacent to marshy pastures (as indicated above) rather than to

woodland are associated with a high diversity of species in the Ceredigion area.

When the percentages of hedges dated in 1791 in each land-use category were compared (Table 4a),marsh hedges had higher percentages than pasture/pasture or lane/pasture hedges. These differences

were significant statistically (Table 4b). There was also a greater percentage of hedges dated in

1791 in the pasture/pasture category compared with the lane/pasture category but this was not

statistically significant.


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Analysis of species relationships

The species frequencies are presented in table 6. The total data was ordinated using correspondence

analysis (Digby and Kempton 1987) for the 25 species with an overall frequency of greater than

5%. In the scatterplot of the first two iterations, Fagus sylvatica was separated spatially from all

other species and so was eliminated from the data and a re-analysis made. Most species (Figure 2)

are aligned in a continuum roughly parallel with correspondence axis 1. The common planted hedge

and associated species, e.g. Sambucus nigra and Crataegus monogyna are situated at one end of the

continuum and species which are constituents of natural woodland and wet soils, e.g. Alnus

glutinosa and Salix aurita at the other end.

Correspondence axis 1 may represent disturbance of woody vegetation at a landscape level with at

the one extreme hedges comprising mainly planted species where farming is intensive and local

woody-species diversity is low. At the other extreme hedges are colonized by or formed of

woodland/carr species where relict, undrained and unimproved landscapes occur. Vaccinium

myrtillus and Ulex europea and to a lesser extent Sambucus nigra occur as outliers to the main

grouping and appeared to be separated along correspondence axis 2 which may be related to

dereliction of hedges, particularly in upland areas.

A tentative grouping of hedges by species consists of: 1, hedges dominated by the commonly

planted species; 2, marshland relict landscape hedges with Alnus glutinosa and Salix aurita; 3,

derelict hedges, particularly in upland areas with Vacciniummyrtillus and Ulex europea; 4, uplandplanted windbreak hedges with Fagus sylvatica.


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Relationships between individual species and hedge species richness

For each species recorded, the mean diversity of hedge samples where it was present was

calculated. For comparison of species, the mean diversity values are plotted against overall

frequency for each species (Figure 3). This relationship gives three broad groupings of 1, common

and planted species planted, 2, mostly unplanted and rare species typical of natural woodland; 3,

rarer species typical both of disturbed and derelict hedges. Group 2 may include some indicators of

assart type hedgerows with indicator species such as aspen, Populus tremula, present in the most

diverse hedges of all species. Tamus communis was also present in diverse hedges and possibly

represents some effect of soil pH on diversity, as it is a distinct calcicole, though calcareous soils

are rare in the survey area.

Species diversity in relation to species dominance

In order to examine the effect of species dominance on hedge species diversity, the mean species

diversity of all hedge samples with at least one species dominating the sample (i.e. such species

comprising at least 50% of sample length) was compared with that of all hedge samples where no

dominants were present (Figure 4). This was also carried out for individual species so that mean

species diversity was compared in hedge samples where a particular species was dominant with

those where it was not dominant.

Overall, mean species diversity was depressed for those hedge samples where any species exhibited

dominance. There were wide differences between individual species, however, in how much lowermean diversity was in hedge samples where they exhibited dominance compared with those where

there was no dominance. Hedge samples in which Crataegus monogyna, Fagus sylvatica, and

Laburnum anagyroides were dominant had the lowest scores for mean species diversity relative to

hedge samples where they were non-dominant. This may be so because the dominance score for


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these species will in many cases indicate their planting as a pure hedge which may be difficult sites

for colonization by other species. Where dominance ofAlnus glutinosa, Salix cinerea and Corylus

avellana occurs, mean species diversity was not very much lower than in hedges where they were

not dominant, and this was especially true ofQuercus spp..

Discussion

The hedge survey and analysis, though restricted to a small part of Wales and carried out 30 years

ago, exhibits patterns of woody species interaction, particularly with respect to land-use which

should be investigated in other hedged landscapes, with the objectives of uncovering the processes

involved in historical ecology and landscape ecology. Some hedge land-use/species associations

may be candidates for conservation efforts, e.g. in this study some of the marsh hedges and those

with aspen (one very diverse hedge sampled with this species in the survey area has been

designated a UK Site of Special Scientific Interest) and within rural development programmes

given their economic significance to landscapes and tourism. Cherrill et al (2001) looked at an area

of northern England found other land-uses associated with more diverse hedges, including

arable/woodland edge and arable/road hedges. Hedges have in the recent past been subject to

significant changes in composition and diversity because of large scale changes to farming and

hedge management practice (Carey et al, 2008) not all of it negative, despite a recent history of

hedge removal or neglect of hedges.

The species diversity of hedges in this survey was seen to show significant differences in relation tothe variation in many factors including dominance by a particular species, aspect, adjoining land-

use and condition of hedge but not the age of hedge reported previously by several authors in other

areas (see above). The most frequent species such as hawthorn and blackthorn Prunus spinosa were

found in relatively species poor hedges. Where the later species are planted as pure hedges, they


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may dominate and consequently exclude other species. Hedges on marshy ground were the most

diverse possibly because extra niches are present for moisture-loving species to occupy in addition

to representing possible relict landscapes (below). Excess soil moisture may also be equally

important in promoting diversity by restricting potentially competitive species, in particular

hawthorn which is considered to be sensitive to waterlogging.

The highest proportion ofold hedges occur on marshy ground. Marsh hedges may indicate areas

of relict landscapes, their high diversity being representative of a generally high biodiversity

maintained because of the intractability of these areas to agricultural improvement, including

drainage works.

Further work needs to be carried out, particularly on competition between hedges woody species,

and also on the process of colonization of woody species into an established hedge to enable a

model of hedge species diversity and dynamics to be developed.

Hedges in Ceredigion were generally more diverse in woody species compared with lowland

England (Pollard Hooper and Moore 1974; Moore, Hooper and Davis 1967), even though

calcicolous species were mainly absent. Diversity was similar to that found in Shropshire (Cameron

and Pannet 1980) for mainly mixed hedges and higher than hedges in Derbyshire for mainly

hawthorn Crataegus monogyna enclosure hedges (Willmot 1980). The relatively high diversity of

Ceredigion hedges could be a result of high colonization rates in new or reformed hedges because

of high hedge densities and consequently low dispersal distances, though hedge length showed no

relationship with diversity. An example of the high colonization rates in the survey area may be

indicated by the high frequency of hazel Corylus avellana in `new' field-boundaries first recorded in1845-85, whereas in surveys carried out in England (see above), this species tends to be restricted to

old hedges including assarts. There is also, however, the strong possibility that hazel has been a

major planted species in the past. Hedge banks, on which most hedges in the survey occur, may

present relatively easy sites for colonization by shrubs and trees particularly as competition from


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grasses on the bank-crest may not be as severe as in hedges on the flat, and light intensities will be

higher, though drought stress will be more common. Birds often use banks as look-out posts and

may disperse seed preferentially to these sites in droppings.

Acknowledgements

Thanks are due to the Department of Food and Rural Affairs (was Ministry of Agriculture, Fisheries

and Food) for funding the open contract in which this work was carried out, to Professor Roger

Haggar for his advice and to Andrew Parry, Sheila Grant and Cameron Pope of the Institute of

Grassland and Environmental Research computer unit for help with computer systems.

References

Baudry, J. (1984). Effects of landscape structures on biological communities: the case of hedgerow

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Association of Landscape Ecology, Poskilde, Denmark.

Baudry, J. (1987). Hedgerows and hedgerow networks as wildlife habitat in agricultural

landscapes.Environmental Management in Agriculture. ADAS, MAFF. Belhaven Press, London.

Brooks, A. (1980). Hedging a practical conservation handbook. British Trust for Conservation

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Barr, B., Benefield, C., Bunce, B., Risdale, H. & Whittaker, M. (1984). Landscape Changes in

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Buchanan, J. & Fuller, M. (1980). Pembrokeshire ancient woodland. Nature Conservancy

Council/West Wales Naturalist's Trust.

Caesar, J. (55BC). Gallic Wars. Roman Empire Press.


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Cameron, R.A.D. & Pannett, D.J.(1980). Hedgerow shrubs and landscape history: some

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Carey, P.D., Wallis, S., Chamberlain, P.M., Cooper, A., Emmett, B.A., Maskell, L.C.,

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Cherrill, A., Mercer, C. McClean, C. & Tudor, G. (2001) Assessing the Floristic Diversity of

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Clapham, A.R., Tutin, T.G. & Moore, D.M. (1987). Flora of the British Isles. 3rd ed. Cambridge

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Chater, A.O.(1993). The higher plants and vegetation of Cardiganshire, in Davies, J.L. & Kirby,

D.P.(eds.), Cardiganshire county history. Volume 1: From the earliest times to the coming of the

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Davies, W. (1815). General View of the Agriculture and Domestic Economy of South Wales, vol 2,

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Genstat 5 Committee (1987). Genstat 5 Reference Manual. Statistics Department, Rothamstead.

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Hooper, M.D. (1970). Hedges and history.New Scientist, 48, 598-600.

Hoskins, W.G. (1971). Historical sources for hedge dating.

Hedges and Local History. Standing Conference for Local History.

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Linnard, W. (1982). Welsh Woods and Forests : their History and Utilisation. Cardiff, National


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Museum of Wales.

Lister, J. & Whitbread, A. (1987). Ceredigion Inventory of Ancient Woodlands. The Nature

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Moore, N.W. ,Hooper, M.D. & Davis, B.N.K. (1967). Hedges. 1. Introduction and

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Figure 1. Map showing location of survey area (a) and more detailed map of area (b).


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Figure 2. Correspondence analysis scatterplot for the first two iterations for all species with

frequency greater than 5%. Tentative groupings of species are: 1, common planted species and

associated species; 2, mostly unplanted species typical of natural woodland; 3, species typical of

derelict hedges, particularly in upland areas.

Abbreviations: c.m., Crataegus monogyna; p.s., Prunus spinosa; a.c., Acer pseudoplatanus; m.s.,

Malus sylvestris; r.f., Rubus fructicosus agg.; f.e., Fraxinus excelsior; b.p., Betula pendula; b.u.,

Betula pubescens; q.r., Quercus robur; q.p., Quercus petraea; s.a., Sorbus aucuparia; h.h.,Hedera

helix; s.n., Sambucus nigra; r.c.,Rosa canina; c.a., Coryllus avellana; i.a.,Ilex aquifolia; r.s.;Rosa

sherardii; l.p., Lonicera periclymenum; v.m., Vaccinium myrtillus; s.c., Salix cinerea; s.u., Salix

aurita; a.g.,Alnus glutinosa; u.e., Ulex europaeus.


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Figure 3. Graph of frequency by mean diversity of hedge samples where present for each

species.

Tentative groupings of species are: 1, common planted species and associated species; 2, mostly

unplanted species typical of natural woodland; 3, species typical both of disturbed and derelict

hedges.

Abbreviations: h.h., Hedera helix; l.p., Lonicera periclymenum; r.a., Rosa arvensis; r.s., Rosa

sherardii; r.f., Rubus fructicosus; t.c., Tamus communis; c.v., Calluna vulgaris; v.a., Vaccinium

myrtillus; a.c., Acer pseudoplatanus; b.p., Betula pendula; b.u., Betula pubescens; c.a., Corylus

avellana; c.m., Crataegus monogyna; f.e., Fraxinus excelsior; i.a., Ilex aquifolia; p.c., Prunus

cerasus; p.s., Prunus spinosa; q.p., Quercus petraea; q.r., Quercus robur; r.c., Rosa canina; r.i.,

Rubus idaeus; s.c., Salix cinerea; s.p., Salix caprea; s.n.; Salix nigra; s.a., Sorbus aucuparia; t.b.,

Taxus baccata; u.e., Ulex europaeus; u.g., Ulex gallii; u.p., Ulmus procera; a.g.,Alnus glutinosa;

f.s., Fagus sylvativa; l.a., Laburnum anagyroides; l.v., Ligustrum vulgaris; m.s.,Malus sylvestris;

p.t., Populus tremula; p.a., Prunus avium; p.i., Prunus institia; r.p.,Rhododendron ponticum; r.u.,

Ribes uva-crispa; r.n.,Ribes nigrum; s.u., Salix aurita; c.s., Cytisus scoparius; u.g., Ulmus glabra;

v.o., Viburnum opulus; c.b., Carpinus betulus.


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Figure 4. For each species exhibiting dominance in hedge samples- the mean diversity of

hedges samples where dominant by that where non-dominant (dominance indicates a species

occupying 50% or more of a hedge sample). Abrreviations: o., mean for all species; q.p.,

Quercus petraea; q.r., Quercus robur; f.e., Fraxinus excelsior; a.g.,Alnus glutinosa; c.a., Corylus

avellana; s.c., Salix cinerea; p.s., Prunus spinosa; c.m., Crataegus mongyna; c.b., Carpinus

betulus; f.s., Fagus sylvatica; l.a., Laburnum anagyroides; u.e., Ulex europaeus; u.p., Ulmus

procera.


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Table 1. Hedgerow physical data

1. Altitude in metres.

2. Catchment locality,- 10 catchments represented (Figure 1).3. Situation of hedge:

1.earth bank

2.stony bank

3.level ground.

4. Height of hedge in metres.

5. Existing management:

1.clipping

2.laying

3.clipping and laying

4.not managed

6. Past management; scores-as for previous character

7. Age category:

1.recorded in 1791 and subsequently

2.recorded in 1845-85 and subsequently

3.recorded in 1905 and subsequently

8. Total length of hedge in metres; length of hedge between junctions, major breaks or major

changes in direction from which sample was taken

9. Condition of hedge:

1. very well managed, dense and impenetrable to stock

2. hedge open but some impenetrable sections; has got gaps but can be renovated by laying

or minimal planting

3. interrupted line of shrubs; not stockproof and needs replanting from scratch

4. line of scattered trees.

10. Direction of slope on which hedge is situated (8 directions,

i.e north, north west etc.)

11. Major land-use categories on either side of hedge (lane includes both metalled roads and

un-surfaced but permanent vehicular tracks or green lanes)

1. pasture/pasture

2. lane/pasture

3. lane/arable

4. stream/pasture

5. marshy pasture/marshy pasture

6. pasture/marshy pasture

12. Trees present in hedge

13. Ash or other large tree stools present in hedge


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Table 2a. A comparison of each land-use category for the % of hedge samples present in each

condition category

Condition

category

Pasture/

pasture

Lane/

pasture

Lane/

arable

Stream/

pasture

Marsh/

pasture

Marsh/

marsh

1 53 64 88 16 41 22

2 22 20 12 31 25 30

3 17 13 0 45 20 23

4 8 3 0 7 14 25

Sample

no.

646 1066 43 55 150 53


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Table 2b. A comparison of the proportion of dense hedge samples (in condition category 1 of

Table 3a) in each major land-use categories using the Chi-square test.

Lane/

pasture

Lane/

arable

Stream/

pasture

Marsh/

pasture

Marsh/

marsh

Pasture/pasture *** *** *** * ***

Lane/pasture ** *** *** ***

Lane/arable *** *** ***

Stream/pasture ** n.s.

Marsh/pasture *

N.B. Condition categories are as follows: 1, dense and impenetrable; 2, hedge with some gaps; 3,

interrupted and non-stockproof line of shrubs; 4, line of scattered trees.

Probabilities to significances are represented in all tables as follows: n.s., non-significant

probability; *, probability < 0.05; **, probability < 0.01; ***, probability < 0.001.


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Table 3. A comparison of each altitude class for the % of hedge samples in each condition

category and the % of hedge samples having received management

Altitude groups

0-60 60-120 120-180 180-240 240-

% in each

condition

category

1 67 68 57 50 23

2 22 20 20 23 12

3 8 6 15 21 42

4 3 6 8 6 23

Sample

no.

196 288 1019 548 104

%managed 64 54 38 33 12

Sample

no.

206 288 1035 560 111

N.B. Condition categories are as follows: 1, dense and impenetrable; 2, hedge with some gaps; 3,

interrupted and non-stockproof line of shrubs; 4, scattered line of trees.


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Table 4a. A comparison of each land-use category for the % of hedge samples present in each

date group

Land-use category

Pasture/

pasture

Lane/

pasture

Marsh/

pasture

Marsh/

marsh

1791 69 61 87 77

1845-85 31 35 13 17

1905 0 4 0 6

Sample no. 310 343 114 47

Table 4b. A comparison of the proportion of hedges first dated in 1791 in each of the 4 major

land-use categories using the Ch- square test

Lane/pasture Marsh/pasture Marsh/marsh

Pasture/pasture n.s. *** n.s

Lane/pasture * ***

Marsh/pasture n.s.


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Table 5a. The overall % frequency of commonest species in descending order

Rubus fruticosus agg. 92.2

Crataegus monogyna 90.3

Hedera helix 79.0Corylus avellana 74.8

Prunus spinosa 68.9

Rosa canina 56.3

Lonicera periclymenum 46.8

Sorbus aucuparia 46.4

Fraxinus excelsior 42.1

Salix cinerea 39.8

Quercus robur 28.7

Rosa arvensis 25.3

Betula pubescens 23.5

Acer pseudoplatanus 22.8

Quercus petraea 21.8

Fagus sylvatica 15.5

Ilex aquifolium 14.7

Ulex europeaus 14.2

Alnus glutinosa 13.4

Sambucus nigra 9.7

Salix aurita 9.0

Betula pendula 8.5

Malus sylvestris 6.0

Table 5b. Species with an overall frequency of less than 5%

Tamus communis Calluna vulgaris Vaccinium myrtillus

Ulex gallii Acer campestre Aesculus hippocastaneum

Berberis vulgaris Buxus sempervirens Carpinus betulus

Castanea sativa Cytisus scoparius Laburnum anagyroides

Ligustrum vulgare Lonicera nitida Pinus sylvestris

Populus tremula Prunus avium Prunus cerasus

Prunus domestica ssp.domestica Prunus domestica ssp.insititia

Prunus laurocerasus Quercus cerris Rhododendron ponticum

Ribes nigrum Ribes rubrum Ribes uva-crispa

Rosa sherardii Rubus idaeus Salix caprea

Salix caprea x viminalis Salix cinerea Salix cinerea x viminalis

Sorbus aria Sorbus torminalis Spiraea spp.

S ymphoricarpos rivularis Taxus sempervirens Tilia cordata

Ulmus carpinifolia Ulmus glabra Ulmus glabra x plotii

Ulmus procera Viburnum opulus

N.B. Dominance was recorded where a species comprised 50% or more of the hedge sample.

For the interspecific hybrids ofQuercus andBetula the sample was credited with the species which


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the hybrid most resembled. All exotic conifer genera and species except for Pinus sylvestris were

lumped together and recorded as one species- (Cupressus sp., Cupressocyparis leylandii,

Chamaecyparis spp.,Larix spp., Picea abies)


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Table 6a. A comparison of the hedge samples in the 6 commonest land-use categories both for

those species showing the greatest differences in % frequency between them and also mean

species diversity

Species %

frequency

Pastur

e

Pastur

e

di Stream

/

pasture

Lane/

arable

Lane/

pasture

a Marsh/

pasture

Marsh/

marsh

Vaccinium

myrtillus

2 0 11 11 9 ns 9 19

Betula

pubescens

25 45 20 33 16 *** 47 64

Corylus

avellana

73 85 65 80 77 ns 81 83

Crataegus

monogyna

95 86 87 96 91 *** 76 75

Prunus

spinosa

74 75 78 59 71 *** 57 40

Quercus

petraea

14 33 9 20 26 ns 23 45

Quercus robur 25 21 16 28 29 *** 44 52Salix cinerea 39 80 91 30 31 *** 77 94

Sorbus

aucuparia

48 72 49 57 43 *** 59 79

Alnus

glutinosa

10 24 20 7 8 *** 47 57

Salix aurita 8 9 18 20 5 *** 21 47

Sample no 649 58 55 46 1118 150 53

diversity 8.7 9.9 8.7 9.1 9.2 10.3 11.3

Variance 11.3 6.9 6.0 5.5 8.7 3.4 6.5

N.B. The category di. represents a subset of pasture/pasture hedges where ditches were present.

A=comparisons of proportional frequency of species in lane/pasture and marsh/pasture using Chi-

square test.


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Table 6b. A comparison of species diversity of hedge samples in each landuse category using

the t-test

Marsh/

pasture

Lane/

pasture

Lane/

arable

Stream/

pasture

Pasture/

pasture

Marsh/marsh * * * * *

Marsh/pasture * * * *

Lane/pasture n.s. n.s. n.s.

Lane/pasture n.s. n.s.

Stream/pasture n.s.


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Table 7. A comparison of hedge samples in the two main datings (1791 and 1845-85) both for

the those species showing the greatest differences in % frequency between them and also

mean species diversity

First recorded 1791 onwards 1845-85 Chi-squared between

Species more frequent in 1791 hedges

Quercus petraea 24.3 16 **

Alnus glutinosa 21.6 14.5 *

Corylus avellana 94.0 85.1 ***

Species more frequent in 1845-85 hedges

Betula pubescens 31.9 42.8 **

Quercus robur 35.4 46.5 **

Rosa arvensis 31.5 44.9 ***

Acer pseudoplatanus 17.5 24.2 ***

Fraxinus excelsior 39.1 46.4 *

Sorbus aucuparia 57.6 73.6 ***

Prunus domestica 1.5 4.5 *

Malus sylvestris 6.2 11.2 *

diversity 9.9 10.5 n.s.variance 6.1 9.4

No of samples 601 269

N.B. Species diversity of the two datings was compared using the t-test.


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Table 8. A comparison of hedge samples in each condition categories both for those species

showing the greatest differences in % frequency between them and for mean species diversity

Hedge conditions 1 A 2 B 3 C 4

Alnus glutinosa 12.6 13.6 13.7 18.5

Betula pubescens 22.8 23.1 22.4 * 31.8

Betula pendula 6.3 * 9.3 *** 15.4 7.3

Vaccinium myrtillus 3.1 *** 0 *** 15.2 * 7.3

Ulex europaeus 11.7 *** 18.0 *** 18.0 15.0Calluna vulgaris 1.2 * 0 *** 4.4 1.9

Ulex gallii 0.8 0.2 * 2.6 0.6

Mean diversity 9.82 9.19 7.8 6.4

No of sampes 1210 450 344 151

variance 7.82 7.87 10.44 12.44

N.B. Hedge condition categories as follows: 1, dense and impenetrable; 2, open but with some

impenetrable sections; 3, non-stockproof line of scattered shrubs; 4, line of scattered trees.Comparisons of species proportional frequencies between categories are by Chi-square.

Comparisons A, B and C are of 1 vs 2, 1 vs 3 and 1 vs 4 respectively. Only those comparisons of

species proportional frequency showing significant differences

(P < 0.05) are shown. All pair-wise comparisons of condition category species diversity were

significantly different for t-test (P < 0.05).


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Table 9. A comparison of hedge samples on north and south facing slopes both for those

species showing the greatest differences in % frequency between them and for mean species

diversity

Species % north south significance

Vaccinium myrtillus 14.5 3.2 ***

Betula pendula 10.5 5.7 *

Betula pubescens 24.8 17.0 **

Fraxinus excelsior 46.7 36.4 **

Ilex aquififolium 16.5 9.4 **

Quercus petraea 30.4 19.4 ***Sorbus aucuparia 51.8 35.9 ***

Salix aurita 9.8 5.4 *

Rosa sherardii 21.4 13.5 *

Salix cinerea 39.5 31.6 *

diversity 9.3 8.2 ***

Sample no. 552 371 ***

variance 9.076 10.195

N.B. Comparisons of species proportional frequency were made using Ch-square test. Species

diversity of hedge sample aspect classes was compared using the t-test.


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Table 10. A comparison of hedge samples in each altitude class for those species showing the

greatest differences in % frequency between them

Altitude class and significances

Species % 0-60 a 60-120 120-180 b 180-240 240+

Hedera helix 91 ns 91 88 *** 63 22

Lonicera

periclymenum

73 *** 62 52 *** 29 5

Corylus

avellana

61 *** 87 82 *** 70 27

Prunus

spinosa

81 *** 74 68 *** 72 30

Crataegus

monogyna

91 ns 94 88 ns 92 89

Vaccinium

myrtillus

0 *** 0 8 *** 7 40

Sorbus

aucuparia

8 *** 20 56 ** 58 41

Rubus idaeus 1 ns 2 4 ** 7 10

Cytisus

scoparius

0 ns 0 1 *** 4 6

Fagus

sylvaticus

12 ns 12 16 ns 12 40

N.B. The symbol A refers to comparisons of species proportional frequency of the 0-60m and 120-

180m altitude classes using Chi-square test. The symbol B refers to a similar statistical comparison

between 120-180m and above 240m altitude classes.

Hedges Cardigan

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