Four Year Study Involving Wildlife Monitoring of Commercial SRC Plantations Planted on Arable Land and Arable Control Plots

Four year study involving wildlife monitoring of commercial SRC plantations planted on arable land and arable control plots

DTI TECHNOLOGY PROGRAMME: NEW AND RENEWABLE ENERGY

CONTRACT NUMBER B/U1/00627/00/00

URN NUMBER 04/961

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ii ARBRE MONITORING - ECOLOGY OF SHORT ROTATION COPPICE

B/U1/00627/REP DTI/PUB URN 04/961

Contractor

The Game Conservancy Trust (GCT)

Sub-Contractor

The Central Science Laboratory (CSL)

Prepared by

M.D.Cunningham (GCT) J.D. Bishop (CSL) H.V.McKay (CSL) R.B.Sage (GCT)

The work described in this report was carried out under contract as part of the DTI Technology Programme: New and Renewable Energy. The views and judgements expressed in this report are those of the contractor and do not necessarily reflect those of the DTI.

ii i EXECUTIVE SUMMARY

Introduction

This project, funded by the Department of Trade and Industry (DTI) through Future Energy Solutions, was conducted over a four-year period starting in 2000. The project involved wildlife monitoring within Short Rotation Coppice (SRC) plots managed commercially for the project ARBRE (Arable Biomass Renewable Energy) throughout Yorkshire.

Project Aims and Objectives

The objectives of this project were: i) To monitor appropriate flora and fauna within and around a suitable number of commercially managed SRC plantations. ii) To use this information to assess the impact of the ARBRE SRC plantations on wildlife in the area.

The project aims were also to compare the wildlife value of SRC plots with that of surrounding arable land. The SRC plots used in this project were all planted on former arable land. The monitoring of paired arable control plots during this project enables comparisons to be made between SRC and the arable land it replaces.

A further aim was to determine if the fauna and flora monitored was equally distributed throughout the plantations. In order to achieve this monitoring was carried out at various distances from the crop edge both in the SRC and in the arable control plots. The project also aims to compare the surrounding boundary habitat and headlands of SRC plantations with those of arable fields, to determine if any benefits to wildlife resulting from the planting of SRC extend beyond the cropped area.

In order to facilitate these objectives further another four-year study began in May 2002 to determine the conservation value of SRC plots planted on grassland sites. This is also being funded by DTI through Future Energy Solutions. As SRC planted on grassland sites does not differ fundamentally from SRC planted on arable land the same wildlife groups are being monitored using the same methodology. This new study can be seen, as an extension of this project and on completion would provide even more information on the impact of commercial SRC on wildlife as well as allowing the effect of previous land use to be examined.

The information gained as a result of this project and that of the study due for completion in two years time aims to provide guidance on the ecological impact of future commercial SRC developments. Information collected incidentally on weed and insect pest populations during this study will contribute to the effective management of SRC plantations in the ARBRE region and more widely to the pest occurrence and management strategies in SRC crops.

iv Background

At present there is very little information on the impact of large-scale SRC plantations on the countryside and its wildlife. The planting of large scale SRC plots creates a new habitat that could potentially provide opportunities for colonisation by many species of plant and animals. Previous studies carried out on non-commercial SRC have already shown the crop to be beneficial to wildlife. However, these previous studies were carried out on SRC plots that tended to be smaller in size, with a more varied age structure and fewer agricultural inputs than the commercially planted ARBRE plots used in this study.

Replacing existing arable land with SRC could also potentially be detrimental to some species preferring open habitats. Recent declines in bird species associated with farmland habitats have been of concern to conservation groups. In this study, paired arable control plots were also monitored in order to document both gains and losses in wildlife resulting from the change in land use associated with the planting SRC.

Summary of Methodology Adopted

A total of 12 sites were identified as suitable for use in the project along with 12 nearby arable fields as control plots. Four wildlife groups were monitored during the project; birds, plants, general insects and butterflies. Groups such as birds and butterflies were specifically chosen due to their conspicuous nature making them easy to monitor. Many other groups such as small mammals were considered to require additional effort that could not be adequately undertaken within the broad constraints of the project.

Breeding birds were monitored using a point count methodology on two separate occasions during the spring during each year of the project. This enabled the density of birds to be estimated both within SRC plots and arable control fields. Bird densities were estimated both at the edge and interior of the crop, as well as in the boundaries adjacent to the crop.

In order to provide a more complete study of wildlife use in commercial SRC plots throughout the year wintering birds were also monitored by walking transects through the plots. Four visits were made to each site during the last three years of the project, to take account of the high mobility of birds during the winter in response to weather conditions and food supply.

Vegetation was monitored annually throughout the study from a number of quadrats positioned at various distances from the crop edge along two transects in each SRC plantation and arable control field. Vegetation was also monitored from the surrounding headlands. Both percentage vegetation cover and the total number of species present and relative abundance were recorded. Plant species were separated into annuals, invasive perennials and long-lived perennials which enabled succession to be documented within the SRC plantations.

v Butterflies were monitored along transects around the edge of the SRC and arable plots using standard methodology involving timed counts. Monitoring was carried out three times during the summer to allow for seasonal variation between different species. General invertebrates were sampled twice a year within the SRC only using standard beating techniques. Samples were taken at various distances from the crop edge.

Summary of Results

The commercially managed ARBRE SRC plots contained a greater diversity of wildlife than the arable control plots. Higher densities of birds were recorded during the summer in the SRC than the controls. The SRC plots also contained more bird species than the controls. Densities of migrant bird species, such as Warblers were as high in the edge of established SRC as they were in the surrounding hedgerows and adjacent boundaries. Resident bird species tended to prefer the hedgerows to the SRC. The bird community changed in response to increased willow growth. Densities of Tits, Finches and Warblers increased over the study. Thrushes reached a maximum density in 2 year-old SRC, Game birds in 1-year old SRC and those species identified as preferring open habitat such as Skylarks and Wagtails declined as the willow became established. Bird density was higher at the edge than the interior of the plantations. Bird species associated with open habitats such as Skylarks, were largely absent from established SRC. However, the results of this study indicate that recently planted and cut-back plots support higher numbers of Skylarks and Lapwings than the arable fields. The density of birds in the commercially managed ARBRE plots was lower than had previously been recorded in non-commercial SRC; perhaps reflecting the larger size, more uniform age structure and higher levels of agricultural inputs in commercially managed plots.

In the winter there were on average more species of birds in the SRC plots than the arable controls. Recently planted SRC was especially attractive to Buntings, with several Yellowhammer and Reed Bunting flocks recorded. Many groups of birds preferred younger coppice, although tits were more abundant as the plots became more established. Both Snipe and Woodcock were regularly flushed from SRC in the winter, but were only rarely recorded from arable plots.

Established SRC plots contained more species of plants and greater levels of vegetation cover than traditional arable crops. The headlands of both the SRC plots and the arable controls contained more species of plants than the crops themselves. However, the headlands of SRC contained more species of plants than the headlands of conventional arable crops. This probably reflects the fact that the headlands of the SRC plots tended to be wider and subjected to lower levels of chemical drift from herbicides and fertilisers than the headlands of the arable plots.

The majority of plant species found both in arable fields and recently established SRC plots were annuals, characteristic of disturbed ground. There was a significant decrease in the proportion of annuals, as the SRC became established and higher proportions of both invasive and long-lived perennials. The number of species present with a greater than 10% cover increased with each successive year's growth.

v i The amount of vegetation cover varied between sites. In recently established plantations vegetation cover was higher at the edge of the plots. Vegetation cover increased for the first year after planting, but then remained fairly constant. Although vegetation height was not estimated it is predicted that the levels of vegetation cover recorded are generally not sufficiently high enough to significantly reduce yield.

Butterflies were restricted to the headlands of both the SRC and arable control plots. However, the SRC headlands contained higher numbers of butterflies than the arable headlands. The relatively wider, more sheltered and less intensively managed headlands of SRC plots provides a potentially good habitat for butterflies. The butterfly community of both the SRC plantations and arable control plots was dominated by relatively common species, with the Meadow Brown being the most abundant species. The SRC headlands were particularly attractive to less mobile species such as 'Browns' and 'Skippers' that rely on long grass to complete their life cycle. Both 'Blues' and 'Skippers' increased in abundance within the SRC during late summer. Hedgerows surrounding and within SRC also provide shelter, and relatively high numbers of butterflies were recorded at one particular SRC site that is divided into small compartments by internal hedgerows.

Both the number of individual butterflies and number of butterfly species recorded within the SRC increased over the four year period of the study as the willow coppice became more established. Recently planted SRC plots had lower numbers of butterflies than the arable plots probably due to the ground being ploughed prior to planting, destroying much of the existing ground flora. Recently planted SRC also provides very little in the way of shelter for butterflies. However, after two years growth SRC plots planted at the start of the project were significantly better for butterflies than the arable controls.

The majority of invertebrates recorded from the SRC belonged to the orders Coleoptera and Hemiptera, with other orders present in low numbers. The total number of invertebrates was highly variable between sites although there was a tendency for the edge of the plots to have higher numbers of invertebrates than the interior. The mean number of invertebrate orders increased with subsequent growth of the willow coppice. The Blue Willow Beetle Phyllodecta vulgatissimaa pest species formed a high proportion of the total number of invertebrates recorded, and was present at damaging levels in half of the sites surveyed. The distribution of Willow Beetles within the commercially planted SRC plots monitored altered during the summer reflecting the general pattern of colonisation of these beetles. The species lays its eggs in the edge zone in the spring before moving into the crop interior. Higher numbers of Willow beetle were found sixty meters into the crop in May/June, whereas high numbers of second generation beetles were also found in the edge zone in July/ August.

Conclusions and Recommendations

Commercially managed SRC plantations appear to provide a better habitat for wildlife than the arable fields they replace. Many species of birds that are absent from arable land such as warblers, tits and thrushes are able to colonise SRC

v i i plantations. As edge habitat supports higher densities of birds than the interior it is important to retain headlands, rides and open areas within the plantations to increase the overall conservation value. Species preferring open habitat such as Skylarks are largely absent from established SRC. However, recently planted SRC plots appear to be better than either established SRC or arable plots for open species such as Skylark and Lapwing. These are species of high conservation concern, and further research is probably needed to determine whether or not the rapid growth of willow within recently planted plots has a detrimental effect on the breeding success of these species.

Although hedgerows tend to support higher densities of birds than the SRC, those hedgerows surrounding SRC plantations supported more birds than hedgerows surrounding arable fields. Hedgerows also provide a favourable microclimate for butterflies by providing shelter and warmth. Internal hedgerows incorporated into the design of commercial plots could also provide shelter and warmth favourable to butterflies. Planting SRC away from hedgerows and woodland could reduce the availability of over wintering sites for Willow Beetles but would also reduce general biodiversity and may also prevent beneficial insects with the ability to control Willow Beetle from colonising. Blanket spraying may also be harmful to beneficial insects and should be avoided. Better methods of controlling Willow Beetles may be achieved by planting resistant varieties of willow and researching ways of maximising natural predators.

Many plants currently found in SRC may compete with the crop for moisture. Slow growing perennial species associated with more stable woodland habitats have low water and nutrient requirements and are to be encouraged as they reduce the amount of competition within the willow crop for water. The presence of these species within headlands and rides could provide nectar sources for beneficial insects such as parasitic wasps, with the ability to control pest outbreaks. This is especially important given the abundance of Blue Willow Beetle.

There was an increase in the abundance of several commonly occurring perennial species within the ARBRE plantations, although invasive perennials such as Nettle also increased. A relatively high input of fertilisers and herbicides in commercially managed plots may contribute to the type of plant community that develops within those plots. Further research may be needed to achieve a level of integrated pest management and gain maximum yield while retaining the conservation value of the plots.

Commercial SRC plots provide shelter and warmth favourable to butterfly species, in particular 'Browns' and 'Skippers' that form colonies associated with grass species. It is important to retain suitable headlands to support these species. The wide headlands within SRC plots designed to allow access to machinery also create more habitat for butterflies than the headlands of conventional arable fields. Headlands and margins should be incorporated into the design of commercial SRC plots, unmanaged long grass should be retained as over wintering habitat for caterpillars, and cutting the grass in summer and autumn should be avoided. Ground flora such as Thistles Cirsium should be allowed to become established within the rides.

vi ii CONTENTS

1. INTRODUCTION...... 1 1.1. Wildlife groups monitored ...... 2 1.2. Methods ...... 4 1.2.1. Site selection ...... 4 1.2.2. Site description and management ...... 4 1.3. References ...... 7

2. THE BREEDING BIRDS OF SRC...... 8 2.1. Summary ...... 8 2.2. Introduction ...... 9 2.3. Methods ...... 10 2.3.1. Methodology used for recording birds in SRC and arable plots...... 10 2.3.2. Data analysis...... 10 2.4. Results ...... 12 2.4.1. Species list...... 12 2.4.2. Songbird density within SRC and arable plots...... 13 2.4.3. Numbers of bird species present within SRC and arable plots...... 14 2.4.4. Comparison between SRC and arable boundaries ...... 16 2.4.5. Use of SRC plots by different groups of birds ...... 18 2.4.6. Comparison of bird density within the edge, interior and boundary of SRC plots only...... 21 2.4.7. Differences in the boundary, edge and interior of SRC plots in terms of the bird groupings present ...... 24 2.4.8. Use of SRC plots by species preferring open habitats.... 31 2.4.9. Comparison between different age classes of SRC...... 35 2.5. Discussion ...... 38 2.6. References ...... 41 2.7. Appendix...... 43

3. VEGETATION WITHIN SRC AND ARABLE PLOTS...... 45 3.1. Summary ...... 45 3.2. Introduction ...... 46 3.3. Methods ...... 47 3.3.1. Methodology used in recording vegetation in SRC and arable plots...... 47 3.3.2. Data analysis...... 48 3.4. Results ...... 49 3.4.1. Species List within SRC and arable control plots...... 49 3.4.2. Comparison between numbers of plant species present within SRC and arable control plots...... 50 3.4.3. Effect of distance from the crop edge on numbers of plant species ...... 54

ix 3.4.4. Changes in the number of species present within SRC plots with increased growth...... 54 3.4.5. Differences in vegetation cover in SRC and control plots at various distances from the edge of the crop...... 63 3.4.6. Changes in plant species composition and extent of vegetation cover with increased SRC growth...... 67 3.4.7. Weed competition in SRC crop...... 72 3.4.8. The Influence of surrounding landuse and type of boundary on numbers and types of plant species ...... 72 3.5. Discussion ...... 75 3.6. References ...... 79 3.7. Appendix...... 81

4. BIRDS IN WINTER...... 85 4.1. Summary ...... 85 4.2. Introduction ...... 86 4.3. Methods ...... 87 4.4. Results ...... 88 4.4.1. Comparison between the total number of birds and number of species present in SRC and arable controls during winter ...... 88 4.4.2. Comparison between different groups of species present in SRC and arable controls during winter ...... 90 4.4.3. Use of different age classes of SRC by wintering birds ...... 96 4.4.4. Use of SRC plots by wintering Snipe and Woodcock ...... 99 4.5. Discussion ...... 101 4.6. Reference ...... 104 4.7. Appendix...... 106

5. BUTTERFLY MONITORING...... 108 5.1. Summary ...... 108 5.2. Introduction ...... 109 5.3. Methods ...... 110 5.3.1. Data analysis...... 112 5.4. Results ...... 113 5.4.1. Species groups...... 113 5.4.2. Species and individual numbers ...... 118 5.4.3. Numbers of butterflies in SRC of known age and their arable controls ...... 122 5.4.4. Comparison of numbers of butterflies and species at the beginning and end of the project ...... 123 5.5. Discussion ...... 124 5.6. References ...... 127 5.7. Appendix...... 129

x 6. GENERAL INVERTEBRATE MONITORING...... 130 6.1. Summary ...... 130 6.2. Introduction ...... 131 6.3. Methods ...... 132 6.3.1. Data analysis...... 133 6.4. Results ...... 134 6.4.1. Order composition...... 134 6.4.2. Order abundance and distribution in coppice planted in 1999 ...... 137 6.4.3. Order abundance and distribution in coppice planted in 2000 ...... 138 6.4.4. Changes in mean number of invertebrates with distance into crop (1999 coppice)...... 141 6.4.5. Changes in mean number of invertebrates with distance into crop (2000 coppice)...... 143 6.4.6. Number of willow beetle in coppice...... 145 6.4.7. Distribution of willow beetle in the coppice planted in 1999 ...... 146 6.4.8. Distribution of willow beetle in the coppice planted in 2000 ...... 147 6.4.9. Abundance Index for Willow Beetles ...... 150 6.5. Discussion ...... 151 6.6. References ...... 155 6.7. Appendix...... 156

7. ACKNOWLEDGEMENTS 157

x i 1. INTRODUCTION

This project, funded by The Department of Trade and Industry (DTI) through Future Energy Solutions was conducted over a four-year period, starting in May 2000. The project involved wildlife monitoring of short rotation coppice (SRC) plots planted commercially for the project ARBRE (Arable Biomass Renewable Energy) throughout Yorkshire.

Short rotation coppice (SRC) as a source for renewable energy production is a new crop in the landscape of the UK. The main use of the crop is to produce wood chips for subsequent combustion enabling electricity to be generated. Both willow and poplar have previously been grown as a SRC crop, although only willow varieties were grown in the ARBRE plots monitored during this project. SRC production involves planting willow cuttings in the spring, which are subsequently cut back after one year to produce a coppice stool, from which new, multi-stemmed regrowth occurs. After a further period of around three or four years the stems are harvested and chipped and regrowth continues once again from the cut stool.

Previous wildlife monitoring of SRC has involved non-commercial sites (Sage, 1995; Sage, 1998; Sage, et al, 1994; Sage & Robertson 1996; Sage & Tucker 1998; Coates & Say 1999) and although comprehensive research has been conducted there may be differences in the response of wildlife to plantations on a commercial scale. Commercial SRC plots differ from the plots studied previously in a number of ways (Table 1.1)

We know little about the potential impact that large-scale plantations may have in the countryside and its wildlife. The ARBRE project provides the first commercial SRC operation in the UK, enabling the wildlife value of commercially planted SRC plots to be assessed. An assessment of commercial scale plantations is essential as SRC has the potential to become a major form of land use in certain areas.

The project aim was to monitor appropriate flora and fauna within and around a suitable number of SRC plantations and thus assess the impact of these plantations on wildlife in the area. The planting of SRC creates a new habitat providing opportunities for colonisation by many species of plant and animal. However, it is also likely that some species that occurred before the planting may be displaced. The potential benefits to biodiversity of SRC plantations can only be assessed once comparisons between SRC and the land use that it replaces are possible. The previous studies did not compare SRC with adjacent controls, or before and after plots (Coates & Say, 1999, Sage et al. 1994). In this study the only SRC sites that had been planted on ex-arable land were chosen and compared to arable plots used as control plots. This study is the first to quantify the ecological impact of SRC in comparison to the land use it replaces through the use of adjacent control plots, representing the previous land use (Anon, 2000). An understanding of the crops value to wildlife will provide guidance for the planning of future commercial SRC developments.

1 Previous Plots ARBRE commercial plots

Size Generally small (<5ha) Minimum size of 5ha

Age structure Often mixed age Typically even aged classes

Planning design Often containing Typically uniform clonal trials and plantings of 4-6 intimate structural varieties differences

Agricultural inputs Little use of fertilizers Fertilizers and or insecticides insecticides may be used

Land Quality Typically ex-pastoral Grade 1 or 2 arable or low quality land land is typical for project ARBRE

Growth Rates Many plots consisted Novel, fast growing of trial, relatively slow varieties, 2-3 year growing varieties, 3-5 rotations may be year rotations typical possible

Table 1.1 Differences between SRC used in previous studies and commercial SRC plantations

In conjunction with this study another study began in May 2002 to determine the conservation value of SRC plots planted on grassland sites. This was also funded by DTI through Future Energy Solutions and will also be conducted over a similar four-year period. As SRC planted on grassland sites does not differ fundamentally from SRC planted on arable land the same wildlife groups and methodology used in this study is being used. The grassland study will provide data on a further ten sites and could be combined with the data from this study to increase the sample number from 12 sites to 22 sites, allowing previous land use to be examined as a separate variable.

1.1 Wildlife groups monitored

Four wildlife groups were monitored during the four-year study. These were birds, plants, general invertebrates and butterflies. Past research has shown that these groups underpin the ecology of SRC (Sage & Tucker, 1998).

2 Birds are highly conspicuous and a relatively easy group to monitor (Spellerberg, 1991). Many farmland species have declined because of agricultural intensification and are therefore of conservation concern (Gregory et al, 2002). It is therefore important from a conservation perspective to monitor the effects that a change in land use from arable crops to SRC has on birds both during the breeding season and during winter.

Butterflies were also chosen because they are a particularly conspicuous group of invertebrates and act as an indicator species for other insect groups (Sage et al, 1994). Butterfly fauna within arable land is generally only thought to be suitable for butterfly pests of brassicas (Sparks & Parish, 1995). The majority of British butterfly species breed in woodland (Sage et al, 1994). Consequently, SRC resembling a woodland habitat in structure may prove beneficial to butterflies.

General invertebrates were sampled as another indicator of biodiversity within the SRC plots. Large numbers of invertebrates are known to be associated with Willow Sa/ix spp. (Kennedy & Southwood, 1984). This study aimed to determine the value of commercially planted SRC for this group of species. A number of invertebrates found within SRC are pest species and their presence can lead to economically significant yield losses (Sage & Tucker, 1998). This study hopes to quantify the numbers of invertebrate pests during different times in the summer and at different distances from the edge. The results obtained from this study can be used to determine the best management practices to control insect pests within commercially planted SRC.

A covering of ground vegetation within SRC plots can be beneficial in enhancing the wildlife value of the crop as well as improving soil structure and the landscape value of the crop (Sage et al., 1994). It can also provide a habitat for the natural agents of pest control (Sage et al., 1994). Previous studies indicate that succession from annual species to long-lived perennial species occurs within SRC (Sage, 1995). This study gives the opportunity for plant succession to be monitored within commercially planted SRC, enabling the best management practices to be taken in conserving biodiversity and controlling weeds.

The four-year time scale of the project was designed to encompass the full growth cycle of SRC for energy production. This allowed changes in floral and faunal communities over time and in response to management techniques employed in the plantations to be documented.

3 1.2 Methods

1.2.1 Site selection

Through visits and discussions with landowners and representatives of the project ARBRE potential SRC plots for this study were examined. A total of twelve SRC sites and twelve control sites were then selected based on the following criteria:

1) Sites to be greater than 5 ha in area 2) Sites to be within 50 miles of the Eggborough power station 3) Paired control sites to be of a similar size and situated close to but be independent of the selected SRC plantations 4) Sites to be uniform without unusual typographical features such as rivers running close by 5) Both SRC plantations to have been situated on formerly arable land 6) All SRC sites to undergo similar management throughout the study

1.2.2 Site description and management

Twelve SRC sites were chosen based on the above criteria. Of these, six sites were planted in 1999 and were cutback in February 2000, the remaining six sites were planted in 2000 and cutback one year into the study in February 2001. This enabled comparisons to be made between two different age classes of SRC. All sites were planted with a similar mix of willow as specified by ARBRE (Table 1.2).

Planting season 1999 Planting season 2000 Tora 30% Tora 30% Jorunn 20% Jorunn 20% Jorr 20% Jorr 20% Orm 15% Orm 10% Ulv 10% Ulv 10% Bowles Hybrid 5% Bowles Hybrid 10%

Table 1.2 Variety mix used for 1999 and 2000 SRC plots

Generally there were only minor differences in the way that the sites were managed throughout the period of the study. Each of the sites had a Weedazol herbicide application of 10L/ha in the spring following the first cutback. The majority of the sites were subjected to further applications of a range of herbicides in subsequent springs. Gapping up was carried out on six of the sites following cutback. On two of the sites, site 7 (Shire Oaks) and site 10 (Howden) some gapping up was carried out the spring after cutback.

One of the sites, Site 12 (Foggathorpe Plantations) was completely dug up and replanted in 2001 due to crop failure. In the second year of the study an alternative

4 site was initially found. However, due to Foot and Mouth precautions in 2001 access to the proposed new site as well as site 7 (Shire Oaks) was not possible.

As a consequence of Foot and Mouth disease only ten sites could be surveyed during this year. In the final two years of the study it was possible to resume surveys of all twelve sites including the replanted site at Foggathorpe. In all subsequent analysis involving the age class of SRC, the fact that this site was replanted was taken into consideration.

Site 3 (Paddock House Farm) was the first of the sites to be harvested in February /March 2003. Five other the sites: Market Place Farm (Ellerker), Market Place Farm (South Cave), Charity Farm and North Duffield Lodge were harvested the following year (January/February 2004).

Site Name Year No. Area (ha) Cut-back Harvested & Location Planted Far Shires 1 1999 12.11 Feb 2000 Jan 2004 Eastingwold Hawthorne House Farm 2 1999 5.00 Feb 2000 * Dunkeswick Paddock House Farm 3 1999 12.85 Feb 2000 Feb 2003 Sicklinghall Charity Farm 4 1999 5.00 Feb 2000 Jan 2004 Goole Fields Market Place Farm 5 1999 14.55 Feb 2000 Jan 2004 Ellerker West Farm 6 1999 27.11 Feb 2001 * Storwood Shire Oaks 7 2000 10.00 Feb 2001 * Alne North Duffield Lodge 8 2000 8.60 March 2001 Jan 2004 Selby Market Place Farm 9 2000 16.57 Feb 2001 Jan 2004 South Cave Rowland Hall Farm 10 2000 18.74 Jan 2001 * Howden Oak Farm 11 2000 14.59 Feb 2001 * Foggathorpe Foggathorpe 12 Plantations 2000•** 14.35 * * Foggathorpe ** site 12 replanted in 2001 due to crop failure • site not cut during study period • Table 1.3 Details of SRC sites used for wildlife monitoring of ARBRE plantations

5 Site Name Area No. Crop grown during each year & Location (ha) 2000 2001 2002 2003

Far Shires 1 12.0 W W W W Eastingwold Hawthorne House 2 Farm 8.0 W/O W/B/P B/W W/BA Dunkeswick Paddock House 3 Farm 11.75 W/B W W W Sicklinghall Charity Farm 4 5.5 W W W OSR Goole Fields

Market Place Farm 5 13.0 BA OSR W P Ellerker

West Farm 6 20.0 W/B/O B/W/SAS O/SAS M/O/W/SAS Storwood

Shire Oaks 7 8.1 OSR * * W W Alne North Duffield 8 Lodge 9.0 L BA BA OSR Selby Market Place Farm 9 13.0 BO/B W SB/W W/O SR South Cave Rowland Hall 10 Farm 18.0 W BA OSR W Howden Oak Farm 11 14.0 W SAS SAS SAS Foggathorpe Foggathorpe 12 Plantations 14.0 W * * B B Foggathorpe

Table 1.4 Details of arable control plots used for wildlife monitoring of ARBRE plantations

Crops grown W= Wheat, O=Oats, BA=Barley, B=Beans, OSR=Oil Seed Rape, L=Linseed, SAS=Set-aside, SB=Sugar Beet, P=Peas, M=Maize, BO=Borage **

** Sites not surveyed due to Foot & Mouth disease precautions

6 1.3 References

Anon (2000) ETSU Contract No. B/U1/0062/00/00. Arbre Monitoring- Ecology of short rotation coppice proposal.

Coates, A. & Say. A. (1999) Ecological Assessment of Energy Coppice. Report B/W5/00216/00.REP. ETSU, Harwell, Oxford.

Gregory R.D., Wilkinson N.I., Noble D.G., Robinson J.A., Brown A.F., Hughes J. Procter, D.A., Gibbons D.W. & Galbraith C.A. (2002) The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002-2007. British Birds 95: 410-450.

Kennedy, C.E. and Southwood, T.R.E. (1984) The number of species of insects associated with British trees: a re-analysis. Journal of Animal Ecology 53: 455-478.

Sage R.B., Robertson P.A. & Poulson J.G. (1994) Enhancing the conservation value of short rotation biomass coppice- Phase 1 the identification of wildlife conservation potential. Report of the Energy Technology Support Unit, Department of Trade and industry

Sage R.B. (1995) Factors affecting wild plant communities occupying short rotation coppice crops on farmland in the UK and Eire. Brighton Crop Protection Conference- Weeds-1995 7D-5: 985-990.

Sage R.B. & Robertson, P.A. (1996). Factors affecting songbird communities using new short rotation coppice habitats in spring. Bird Study, 43: 201-213.

Sage R.B. & Tucker K. (1998) Integrating crop management of SRC plantations to maximise crop value, wildlife benefits and other added value opportunities. Report of the Energy Technology Support Unit, Department of Trade and Industry.

Sage R.B. (1998) Short rotation coppice for energy: towards ecological guidelines. Biomass & Bioenergy, 15: 39-47.

Sparks T.H. & Parish T. (1995) Factors affecting the abundance of butterflies in field boundaries in Swavesey Fens, Cambridgeshire, UK. Biological Conservation 73: 221-227.

Spellerberg I. (1991) Monitoring ecological change. University Press, Cambridge.

7 2. THE BREEDING BIRDS OF SRC

2.1 Summary

Breeding birds were monitored within 12 SRC plots and 12 arable control plots on two separate occasions each year (May and June) over a four year period. Birds were recorded within a 50-metre semi-circle from three separate positions (boundary i.e. hedgerows and margins, edge and interior) of the plots, and from this the density of birds per hectare was calculated.

Over the four-year period a total of 45 species were recorded in the SRC plots, compared to 35 species in the arable controls (Table 2.1, on page 43 lists the species recorded during each year of the study). Higher densities of birds were found in the SRC plots in comparison to the arable controls. The SRC boundary held higher densities of birds than the arable control boundaries, suggesting any benefits to birds provided by SRC extend beyond the actual plantation area.

The arable control boundaries contained a higher density of birds and more species than the arable crop. For the first two years of the study the boundaries of the recently established SRC contained higher densities of birds and more species than the edge of the SRC plantation. However, as the SRC continued to grow the difference between SRC edge and SRC boundary was not significant. Resident species were more abundant in the SRC boundary than the SRC edge for the first three years of the study. In contrast, migrant species only showed a preference for SRC boundary in the first year of the study, suggesting established SRC edge is a good habitat for this particular group of birds. Higher densities of birds were recorded at the edge of the SRC than the SRC interior, with thrushes and migrant warblers significantly more abundant in the edge.

Recently planted and cutback SRC contained similar numbers of species than the controls, and the density of birds in the interior of these plots was also similar to the arable controls. However, recently cutback plots were significantly better for Skylarks (a red-list species, see Table 2.2, page 44) than the arable controls. Recently planted SRC plots also contained higher densities of Waders, in particular Lapwings (also of conservation concern) than arable control plots.

There was a significant increase in bird density and number of species during the first two years SRC growth. Tits, Finches (predominantly Chaffinches) and Warblers (predominantly Willow Warblers) increased within the SRC with increased Willow growth. The highest density of Game birds was found in one-year-old SRC, and the highest density of thrushes in two-year-old SRC. Birds identified as species requiring open habitats such as waders, skylarks, wagtails and pipits declined with increased SRC growth, and were absent from plots with more than 2 years growth.

8 2.2 Introduction

Birds are a highly mobile group of species able to rapidly colonise new habitats. Due to their conspicuous nature and specific habitat requirements birds are relatively easy to monitor and are a useful indicator on the effect of landuse change on wildlife generally (Spellerberg, 1991). Previous studies have shown that short rotation willow coppice (SRC) may provide a valuable habitat for a range of bird species. In earlier research carried out in Sweden, Goransson (1990) compared bird populations in fields before and after cropping with SRC and found several new species benefiting from the introduction of SRC. In an extensive survey of nearly 30 sites, Sage et al., (1994) found that SRC held higher densities of birds and more bird species than would be expected in traditional arable crops.

The planting of agricultural land with SRC results in a more structurally diverse habitat closely resembling traditional woodland coppice. Woodland provides a suitable habitat for many species of birds, and has been shown to be richer in species than farmland (Fuller et a., 2001). The birds previously found to utilise SRC were typically those species commonly found in hedgerow and shrub (Sage & Tucker, 1998). Many of these species are of conservation concern having undergone population declines in recent years (Gregory et al., 2002). The density of songbirds within SRC may be similar to that found in traditional coppice habitats (Sage et al., 1994).

Many farmland species are associated with open habitat and so it is important to ensure that the planting of SRC does not cause further reductions in these species. It has been suggested that SRC may actually displace species that nest on the ground in traditional crops (Baillie et al., 2001). Previous studies however suggest that recently cut coppice may provide a suitable habitat for open ground nesting birds such as the Lapwing and Skylark (Sage & Robertson, 1996; Sage et al., 1994), both of which are currently subject to steep population decline in the UK due to changing agricultural practices (Aebischer et al., 1999).

The previous research carried out on birds in SRC although comprehensive has usually involved non-commercial sites. Commercial SRC sites may differ from previously studied non-commercial sites in the number of individual birds and species they support. This present study allows us to see whether commercially planted SRC plots support similar birds at similar densities to the smaller non commercial plots studied previously. In this study adjacent arable control plots are also used for the first time allowing direct comparisons to be made between the SRC plots and arable land within the same region. The use of arable control plots also enables us to see if ground nesting birds, such as skylarks are displaced due to the planting of SRC plots.

As well as comparing SRC with arable plots the present study also attempts to compare the extent to which birds use the SRC edge, boundary and crop interior compared to other field edge habitats. This was achieved by monitoring birds in both the edge and middle of the SRC and controls as well as the surrounding boundaries. The majority of birds within agricultural landscapes are associated with

9 the interface between different habitats (Weins, 1989). It was expected therefore that birds would make more use of the edge of the willow plantation than the middle. The present study also allows comparisons to be made between the boundary habitats of SRC plots and the boundary habitats of arable controls to determine if any benefits of SRC to birds extend beyond the cropped area.

This particular study also allows the effect of age class on the community structure of birds to be considered. In previous studies Warblers were found to prefer willow growth in its second or third year, whereas Tits were found to prefer older growth (Sage et al., 1994). The present study enabled the succession of bird communities within commercial SRC plots to be determined.

2.3 Methods

2.3.1 Methodology used for recording birds in SRC and arable plots

Each of the SRC and control plots was monitored on two separate occasions every year throughout the four-year study period. The first survey was undertaken in early May, the second during the last two weeks in June. This ensured that both early and late breeding birds potentially present in the SRC and control plots could be recorded. The surveys were undertaken either in the morning between 6am and 9am or in the evening between 7pm and dusk to coincide with peak bird activity. Each of the 12 control plots was monitored on the same day and same time during the day as the paired SRC plots.

Birds were monitored in both the SRC and control plots using a point count methodology. This is a widely used method of sampling relative songbird abundance (Bibby et al., 1992). The method involves recording all birds, both observed and heard within a 50 metre wide semicircle around the observer over a 5- minute period at various points within the site. Three different locations were sampled in each of the SRC and arable plots, the edge of the crop, the middle of the crop (more than 50 meters from the edge) and on the plot boundary.

Three separate point counts were carried out at each of the locations within the SRC and control plots. Each of the point counts was at least 50 meters apart. For the purpose of analysis an average was obtained for each location within the plot from the three point counts.

Care was taken to ensure that the point counts were located in situations with similar topographical features such as basic boundary types. The boundaries were chosen to include habitats such as field margins and hedges. Woodland edges and boundaries adjacent to buildings or gardens were avoided. The positions of the point counts were marked on sketch maps so that the location of the point counts remained the same in consecutive years.

10 2.3.2 Data analysis

The means of the bird count data were calculated for each position within the crop for all 12 SRC and arable control plots. From this the number of individual birds per hectare and the mean numbers of species per point count was calculated. These data did not approximate to a normal distribution and therefore were transformed using log (x+1) for analysis.

Birds were also grouped into various categories to allow separate analysis of the value of SRC to individual groups of birds to be carried out. The number of birds per hectare from each of these groups was also calculated. The groups of birds used in the study were as follows:

Thrushes Tits Finches Buntings Migrant Warblers Migrants Residents Game species Accipter species (Wren, Robin, Dunnock) Species preferring open habitat (Waders, Skylarks, Pipits and Wagtails)

As many of the species preferring open habitat such as Skylarks and Lapwings are of conservation concern, this category was sub-divided so that numbers of waders per hectare and numbers of Skylarks per hectare could be analysed separately.

Data was entered into SYSTAT statistical computer package and analysed using general linear modelling.

11 2.4 Results

2.4.1 Species list

Summary

During the four-year period of the study a higher total number of species were recorded in the SRC than the arable plots, although the change in habitat resulting from the planting of SRC suits some species better than others. Several species of conservation concern, such as Lapwings and Skylarks were not found in established SRC plots, although it is worth noting that these species were more frequently recorded on newly planted or cutback SRC plots than on traditional arable fields.

Forty-five species of birds were recorded within the 12 SRC plots and SRC boundaries in this study during the four-year study period. Of these, 37 species were recorded within the willow crop. Eighteen species were recorded in SRC plots and SRC boundary during every year of the study; 11 of these species were recorded every year within the willow crop.

In contrast thirty-five species were recorded in arable control plots and arable boundaries during the study. Of these, 21 species were recorded within the arable crop. Thirteen species were recorded in arable plots and arable boundary during every year of the study, although out of these only two species, Skylark and Yellow Wagtail were recorded as present in the crop during each year of the study.

The species recorded within the SRC plots differed from those found within the control plots. In the arable controls the most frequently recorded species was Skylark. The majority of species recorded from arable plots were also found in the SRC, the exceptions were Barn Owl, Shelduck and Stock Dove. However, out of these species only Stock Dove was recorded on more than one occasion. Four other species (Lapwing, Skylark, Yellowhammer and Yellow Wagtail) were more commonly recorded in arable plots than established SRC. However, all these species were more frequently recorded on recently planted or cut SRC than arable plots.

The species most commonly recorded in established SRC were Willow Warbler (present in 28% of point counts), Chaffinch (21%), Blackbird (18%), Blue Tit (11%), Reed Bunting (7%), Pheasant (7%) and Wren (6%). In SRC with only 1 years growth Meadow Pipits were also frequently recorded (present in 7% of all point counts in SRC of this particular age class).

The species recorded are presented in Table 2.1 ( page 43) showing the number of sites present during each year of the survey.

12 2.4.2 Songbird density within SRC and arable plots

Summary

The SRC contained significantly higher densities of birds per hectare than the arable controls throughout the study. However, the interior of the recently cutback and planted plots did not differ from the interior of the arable controls.

The edge zone of the SRC plots (i.e. within the first 25 metres of SRC) contained a higher density of birds than the edge of the arable controls throughout the period of the study (Figure 2.1). The mean density of birds at the SRC edge ranged from 3.2 birds per hectare in year 1 of the study (2000) to 4.7 birds per hectare in year 4 (2003). In comparison the mean density of the arable controls was 0.83 birds per hectare. The higher density of birds in the SRC edge compared to the edge of the arable plots was significant during every survey throughout the project, with the exception of the first visit in May 2000 (year 1) when there was no obvious difference between the SRC edge habitat and the arable edge habitat.

The interior of established SRC plots also contained a higher density of birds than the interior of the arable plots. The density of birds recorded in the SRC interior ranged from a minimum of 1.8 birds per hectare in year 4 to a maximum of 2.86 birds per hectare in year 2. This was higher than the mean density of 0.77 birds per hectare in the interior of the arable controls (Figure 2.2). In year 1 the density of birds within the SRC interior was similar to that found in the interior of the arable controls. However, there were significantly more birds per hectare in the SRC interior in May of year 2 (F1,9 =6.25, p<0.05) and year 3 (F1,11 =19.28, p<0.01), as well as in June of year 2 (F1,9 =10.57, p=0.01) and year 4(F1,11 =23.31, p=0.001).

E 10

PLOT ■ Control a SRC 2000 2001 2002 2003 survey year

Fig 2.1 Density of birds recorded within the edge zone of SRC (first 25 metres of SRC) and arable control plots edge zone during each year of the project

13 PLOT ■ Control 0 SRC

survey year

Fig 2.2 Density of birds recorded within the interior of SRC and arable control plots during each year of the project

2.4.3 Numbers of bird species present within SRC and arable plots

Summary

The recently planted and cutback SRC in year 1 of the study did not differ significantly from the arable controls in terms of the number of different species recorded per point count. The SRC plots contained significantly more species per point count than the arable controls throughout the remaining three years of the study.

A higher number of different species tended to be recorded during each 5-minute point count from the SRC edge than the control edge. Although no significant difference between SRC and control edge was found in year 1 or in May of year 2. However, more species were recorded in the SRC edge than the arable control edge in June of year 2 (F1,9 =20.44, p=0.001) and in every subsequent survey throughout the remainder of the project.

The mean number of species recorded each year from the point counts at the edge of the SRC ranged from a minimum of 0.6 species per point count in year 1 to a maximum of 1.5 species per point count in year 3. In comparison the mean number

14 of species recorded from the edge of the arable controls throughout the study was 0.3 species per point count (Figure 2.3).

2- PLOT 1 - ■ Control 0 0 SRC 2000 2001 2002 2003 survey year

Fig 2.3 Total numbers of species per 5 minute point count recorded within the edge of SRC and arable control plots during each year of the project

The number of species recorded in the plot interior follows a similar trend to that observed in the edge of the plots. The difference between the SRC and control interior was significant in June of year 2 (F1,9 =8.25, p<0.05) and throughout the remaining visits of the project (Figure 2.4).

In the SRC interior the mean number of species recorded per point count ranged from 0.5 species in year 1 to 1.0 species in year 4. The arable interior was similar to the arable edge with a mean of only 0.3 species.

15 8

6- Q O 5- 8 . m o 4 Q _Q „

2- PLOT 1 - ■ Control 0 0 SRC 2000 2001 2002 2003 survey year

Fig 2.4 Total numbers of species per 5 minute point count recorded within the interior of SRC and arable control plots during each year of the project

2.4.4 Comparison between SRC and arable boundaries

Summary

There was evidence that the boundaries of established uncut SRC contain both higher densities of birds per hectare and more species than the arable control boundaries. This indicates that any benefits to birds associated with SRC establishment extend beyond the boundary of the cropped area.

The boundary habitat contained both higher numbers of birds and more species than the SRC edge in the first couple of years of the study.

In the SRC boundary, bird density based on birds recorded within a 50-metre semi circle incorporating boundary hedgerows ranged from 9.3 birds per hectare in year 1 to 4.87 birds per hectare in year 4. Bird density within the arable control boundaries also showed some variation between survey years and ranged from 6.9 birds per hectare in year 1 to 3.2 birds per hectare in year 4 (Figure 2.5).

In June of year 2 a significantly higher density of birds was recorded in the SRC boundary than the control boundary in June of year 2 (F1,9 =14.12, p<0.01).

16 The number of species recorded per five-minute point count in the boundaries of recently established SRC (year 1) was similar to that recorded in the boundaries of the arable controls. However, there was some evidence to suggest that the boundaries of established SRC plots were more species rich than the boundaries of the controls (Figure 2.6). For example, during the June surveys there were more species recorded in the SRC boundary in year 2 (F1,9 =26.48, p=0.001). Similarly, during the May surveys there were more species recorded in the SRC boundary in year 3 (F1,11 =8.89, p<0.05) and year 4 (F1,11 =9.56, p<0.01).

None of the individual bird groups showed any preference between SRC boundary and control boundary during the first two years of the study. During the last two years of the study the SRC boundary appeared to be more attractive to many of the individual bird groups examined. There were higher densities of Thrushes (F1,11 =6.74, p<0.05) and Tits (F1,11 =11.83, p<0.01) in the SRC boundaries than the control boundaries during May of year 3. Similarly in May of year 4 more Thrushes (F1,11 =9.48, p<0.01), Accipter species (F1,11 =4.97, p<0.05) and migrant Warblers (F1,11 =6.60, p<0.05) were recorded in the SRC boundaries than the control boundaries.

PLOT ■ Control 0 SRC

survey year

Fig 2.5 Density of birds recorded in the SRC and control plot boundaries during each year of the project

17 8

7 -

6 - a> m 5 Q. C/3 % 4 I 3 - 3E 2|- PLOT 1 ■ Control 0 0 SRC 2000 2001 2002 2003 survey year

Fig 2.6 Total number of species recorded per 5-minute point count in the SRC and control plot boundaries during each year of the project

2.4.5 Use of SRC plots by different groups of birds

Summary

The SRC plots tended to contain higher numbers of resident birds than the arable control plots from the start of the study. The recently planted and cutback SRC plots supported a higher density of those species identified as preferring open habitat than the arable controls. This group includes Skylarks, Pipits, Wagtails and Waders. Many of these species are of conservation concern. In addition to containing a higher density of residents, established SRC plots contained more migrants per hectare than the controls as well as higher densities of Finches, Tits, Accipters (i.e. Robins, Wrens & Dunnocks), Thrushes, Migrant Warblers and Game birds.

The changing structure of the SRC over the period of the study resulted in different groups of birds occupying the SRC at different stages of development. In year 1 there was very little difference between the recently planted /cutback SRC plots and the arable controls. The exception was for those species identified as characteristic of open habitats; Wagtails, Pipits, Skylarks and Waders. During this year this group of species occurred at higher density in the SRC plots than the controls both in May (Fi,ii =6.90, p<0.05) and June (F1,11 =6.52, p<0.05).

18 The recently planted/cutback SRC plots contained no Tits. Migrant Warblers were rarely recorded in the recently cutback SRC and were not present in the recently planted plots (Figure 2.7). The number of migrant species overall in these recently established SRC plots monitored in year 1 was low, and restricted to one species, the Yellow Wagtail. As a result there was no difference between these plots and the arable controls in terms of migrant density during this year. Resident species tended to occur at higher densities in the SRC plots during year 1, although the difference between SRC plots and arable plots for this group of species was not significant.

In year 2 there was a higher density of resident species in the SRC compared to the arable controls both in May (F1,9 =6.76, p<0.05) and June (F1,9 =28.13, p<0.001). By June of year 2 there was a higher density of migrants in the SRC plots than the arable controls (F1,9 =7.96, p<0.05). This continued to be the case with established SRC plots supporting significantly more migrants than the controls during every visit throughout the remaining two years of the project.

In year 2 of the study the number of Tits, Buntings and Game birds per hectare both within the SRC and controls was low and differences between the plots for these groups was not significant. During this year four out of the ten plots surveyed were cutback after one year's initial growth. This meant there was still available habitat within the SRC for species preferring open habitat during this year, and no difference between the SRC plots and the controls in terms of the numbers of these species per hectare (Figure 2.7).

In year 2 the six remaining SRC plots with one year's growth (planted 1999) supported a higher density of Thrushes in May (F1,5 =25.00, p<0.005) than the controls. There were also more Finches (F1,5 =29.24, p<0.005), Accipter species (F1,5 =8.02, p<0.05) and migrant Warblers (F1,5 =8.88, p<0.05) in the SRC with one year of growth than the controls during June of that year. There was no difference between the four cut SRC plots and the arable control plots for any of the separate bird groups during this year.

In the final two years of the project the established SRC continued to support higher densities of Thrushes, Finches and migrant Warblers than the controls. In addition to this there was also significantly more Game birds in the SRC plots during May of year 3 (F1, 11 =9.34, p<0.05); more Tits in the SRC than the controls during both May (F1,11 =14.43, p=0.005) and June of year 4 (F1,11 =10.87, p<0.01); and more Accipter species in the SRC plots in May of year 4 (F1,11 =6.28, p=0.05) (Figure 2.7).

19 Fig and

2.7

arable

Birds/hectare Birds/hectare Birds/hectare Birds/hectare Total 0 2 3 4 0 2 3 0 2 3 0 2 3 1 1 1 1

I ------Robins, 2000 2000 2000 2000 period.

plots number

Game 2001 2001 2001 2001 Dunnocks Finches Tits

2002 2002 2002 2002 birds

(excluding NB:

Wrens 2003 2003 2003 2003

only birds

plot per

sites

hectare boundaries)

surveyed 0 2 3 0 2 3 0 2 3 0 2 3 1 1 1 1

------Species 2000 2000 2000 2000

20 from Migrant

prefering 2001 2001 2001 2001 Thrushes Buntings

Warblers

during different 2002 2002 2002 2002

open year

2003 2003 2003 2003 habitat

2 each

(2001)

bird

year

guilds

due a ■ PLOT

SRC control of

to the

within

FMD

4-year

all

study 12

SRC

2.4.6 Comparison of bird density within the edge, interior and boundary of the SRC plots only

Summary

Recently established SRC edge supported comparatively low densities of birds with much higher densities within the surrounding boundary habitat. In contrast, in established SRC plots the density of birds within the SRC edge was comparable to that found in the boundaries. There was no difference between the edge and interior of the recently established SRC. However, in year 3 and year 4 the edge supported a higher density of birds than the interior.

The boundary habitat contained both higher numbers of birds and more species than the SRC edge in the first couple of years of the study. As the willow crop established, the SRC edge was comparable to the boundary both in terms of numbers of total individuals and numbers of species.

In the first two years of the study there was no difference between the edge and interior of the SRC in terms of the number of birds per hectare. In the more established SRC a difference between the edge and interior became more apparent. In year 3 there were significantly higher numbers of birds recorded at the edge of the plots than the interior both in May (F1,11 =24.94, p<0.001) and June (F1,11 =10.25, p<0.01). Similarly, in the final year of the study there were significantly higher numbers of birds in the edge than the interior both in May (F1,11 =23.42, p=0.001) and June (Fi,ii =17.40, p=0.005), (Figure 2.8).

For the first two years of the study SRC edge supported a lower density of birds than the SRC boundaries. In year 1 there were more birds in the SRC boundary than the edge both during May (F1,11 =14.94, p<0.05) and June (F1,11 =9.48, p=0.01). Similarly, there were more birds in the boundaries in year 2 both in May (F1,9 =25.23, p<0.01) and June (F1,9 =17.61, p<0.005). As the SRC became established the density of birds in the edge increased with the result that the edge and boundary did not differ in terms of overall bird density for the last two years of the project (Figure 2.8).

There was no difference between the edge and interior of the SRC in terms of the number of species recorded per 5-minute point count at any stage during the study. The total number of species recorded per 5-minute count was also greater in the boundary than within the SRC crop during both the May and June surveys for the first two years of the study, but not during the final two years of the study (Figure 2.9).

21 8 Birds/hectare Birds/hectare Density 10 15 0 5 %P X of year year1

birds SRC

(2000) (2002)

per

plots

hectare

during

within

each 22

the year m E 1/5 _C m E 1/5 _c 5 5 2 (D o 2 0 o

boundary,

15 10- 15 10- of 0 5|- 5|- 0

r r

the ?p %P

project year year

edge ^ .xoP

4 2

(2001) (2003)

and ^

interior of

the

Fig

2.9

Total Number of species Number of species edge 2 4 6 2 4 6 0 3 5 7 8 0 3 5 7 8 1 1

1 r ------

0> <5° number

and A*

year year1 interior

0 0 of

(2000) species (2002)

of 0^ 0

.0 the

recorded SRC

plots 23

per

during

5-minute

each

count year year year

of within

the

4 2

(2001) (2003)

project

the

boundary,

2.4.7 Differences in the boundary, edge and interior of SRC plots in terms of the bird groupings present

Summary

The differences between boundary and edge became apparent at different stages for migrant species than resident species. Resident species were more abundant in the boundary during the first three years of the study. Migrants showed no preference between edge and boundary after one years SRC growth. Some species such as Chiffchaffs were only found in the boundary, suggesting that the SRC plots may be unsuitable for some species. Game birds showed a preference for SRC edge over the boundary in year 3 of the study.

The results suggest an increase in edge effect as the SRC plots become established. Many species occurred at higher densities in the edge of the SRC plot rather than the interior. This was evident both during the last two years of the study and in the SRC with 1 year's growth in year 2 of the study, when migrant warblers and thrushes in particular were more abundant in the SRC edge than the interior.

In year 1 the interior of the SRC contained similar numbers of Finches, Thrushes, Buntings, Game birds and species preferring open habitat as the SRC edge. The interior of the recently planted and cutback plots did not contain any Tits or Accipter species. The SRC boundaries held more Finches (F1,11 =8.71, p<0.05), Tits (F1,11 =9.36, p<0.05), Thrushes (F1,11 =6.93, p<0.05), Accipter species (F1,11 =9.62, p=0.01) and migrant warblers (F1,11 =4.84, p<0.05) than the SRC edge in May of this year. There were also Tits (F1,11 =7.78, p<0.05) and Buntings (F1,11 =6.66, p<0.05) in the SRC boundaries than the SRC edge in June of this year. The only two groups of species recorded with any frequency within the recently established SRC were Finches and species preferring open habitats, such as Skylarks and Waders (Figure 2.10).

In year 2 there was also very little difference between the SRC edge and the SRC interior. However, this reflects the fact that four out of the ten plots monitored i.e. those plots planted in 2000 had recently been cutback. Evidence from this study suggests that as the SRC plots becomes more established a difference between the edge of the plot and the interior becomes more apparent. For example, in the six SRC plots that were not cut back during year 2 (those with one years willow growth) there was a higher density of migrant Warblers (F1,5 =8.58, p<0.05) and thrushes (F1,5 =7.17, p<0.05) during June in the edge of the SRC than the interior.

In June of year 3 there was a higher density of migrant Warblers (F1,11 =5.18, p<0.05), Finches (F1,11 =9.93, p<0.01), Thrushes (F1,11 =7.24, p=0.05) and Game birds (F1,11 =18.98, p=0.001) in the edge of the SRC than the interior (Figure 2.12). Similarly, in year 4 there was once again a higher density of thrushes (F1, 11 =10.13, p<0.01) and Accipter species (F1,11 =7.78, p<0.05) in May; and Finches (F1,11 =14.85, p<0.01) and Thrushes (F111 =6.67, p<0.05) in June in the SRC edge than in the interior (Figure 2.13)

24 As the willow coppice became established several of the bird groups showed no preference between the boundary habitat and the edge of the SRC. Thrushes, Buntings, Finches and migrant Warblers showed no preference between SRC edge and boundary in the last three years of the study (see Figures 2.11, 2.12 and 2.13).

However, Tits and Accipter species continued to show a preference for surrounding hedgerows even after the SRC had become established. For example, in May of year 3 there were more tits (F1, 11 =7.71, p<0.05) in the SRC boundary than the sRc edge. There were also more Accipter species in the SRC boundary than the edge in year 3 in June (F1,11 =6.93, p<0.05) (Figure 2.12).

In the final year of the study there appears to be no difference between SRC edge and SRC boundary in terms of the number of birds per hectare and the number of birds per hectare recorded from each of the individual groups.

25 Fig

Birds/hectare Birds/hectare Birds/hectare Birds/hectare 2.10 2 3 3 2 3 4 2 3 4 1 1

------Robins,

boundary, Total

Game Dunnocks

Tits number

birds

Wrens edge

and birds

interior

per 3 2 3 2 3 2 3 3 4 1 1 1

Species

hectare ------of 26 Migrant

all prefering Thrushes Buntings

12 from

Warblers

open SRC

different

habitat

during

bird year

guilds 1

(2000)

within

the

Fig boundary,

Birds/hectare Birds/hectare Birds/hectare Birds/hectare 2.11 2 3 0 2 3 4r 2 3 3 4 1 1 1

------Robins,

Total

Game edge Dunnocks

Tits number

birds

and

Wrens

interior

birds

per in "5 3 the ro 2 2 3 2 3 2 3 4 3 4 1 1

Species

hectare ------10

27 SRC Migrant

prefering Thrushes Buntings

from

plots Warblers

open

different

surveyed habitat

bird

during

guilds

year

within

(2001)

the Fig boundary,

Birds/hectare Birds/hectare Birds/hectare Birds/hectare 2.12 2 3 2 3 0 2 3 4 1 1 1

------Robins,

Total

Game edge Dunnocks Finches

number

birds

and

Wrens

interior

birds

per in "5 3 the ro 2 2 3 4 2 3 3 0 2 3 4 1 1 1

Species

hectare ------12

28 SRC Migrant

prefering Thrushes Buntings 0

from

plots Warblers

open

different

surveyed habitat

bird

during

guilds

year

within

(2002)

the Fig boundary,

Birds/hectare Birds/hectare Birds/hectare Birds/hectare 2.13 2 3 2 3 2 3 4 1 1

------Robins,

Total

Game edge Dunnocks

number

birds

and

Wrens

interior

birds

per in "5 the ro 2 2 3 2 3 0 2 3 2 3 4 1 1 1 1

Species

hectare ------12

29 SRC Migrant

prefering Thrushes Buntings 0

from

plots Warblers

open

different

surveyed habitat

bird

during

guilds

year

within

(2003)

the The extent to which surrounding boundary hedgerow or SRC was utilized differed between migrant species and resident species. In the recently planted and cutback SRC plots both migrants and residents were more abundant in the adjacent boundary habitat. However once the SRC became established migrant species tended to show no preference between SRC edge and boundaries (Figure 2.14).

7 -

6 -

5 -

4 -

3 -

2 - POSITION 1 - ■ Boundary a Edge 0 a Interior

survey year

Fig 2.14 Density of migrant bird species within the boundary, edge and interior of the SRC plots during each year of the project

There was some variation between individual species within the migrant category in terms of whether they preferred the SRC or the boundary hedgerows. For example, Willow Warblers were recorded with equal frequency both within the SRC edge and the boundary habitat. In contrast, Whitethroats were much more frequently recorded in the boundary habitat, with birds within the SRC crop accounting for only 16% of all total recordings of that species throughout the study.

SRC boundaries tended to contain higher densities of resident species per hectare than the SRC edge even once the SRC had become established (Figure 2.15). For example, the May surveys revealed significantly more resident species per hectare in the boundaries for year 1(F1,11 =10.40, p<0.001), year 2 (F1,9 =27.38, p=0.001), year 3 (Fi,ii =8.23, p<0.01) and year 4 (F1,11 =5.93, p<0.05).

30 20

15 g

10 C/3 "E in

5 POSITION ■ Boundary 0 Edge 0 a Interior 2000 2001 2002 2003 survey year

Fig 2.15 Density of resident bird species within the boundary, edge and interior of the SRC plots during each year of the project

Of the species recorded on more than one occasion, three were restricted to the SRC boundary and did not occur in the SRC crop; these were Chiffchaff, Corn Bunting and Tree Sparrow. Meadow Pipit was the only species recorded on more than one occasion that occurred only within the crop and not in the boundary. The only group of species found to prefer the edge of SRC plots to the boundaries were Game birds, with higher densities recorded in the plot edges than boundaries in May of year 3 (F1,11 =18.97, p<0.01).

2.4.8 Use of SRC plots by species preferring open habitats

Summary

The results suggest that recently planted SRC provides a better habitat for species preferring open habitat than arable plots. Several of these species, in particular Skylarks and Lapwing are of conservation concern. The increased availability of bare ground created when SRC plots are prepared for planting or cut may be beneficial to these species. Skylarks tended to prefer recently cutback SRC plots to newly planted SRC plots particularly later in the summer, whereas Waders preferred recently planted plots. However, established SRC failed to contain many of these species, with waders noticeably absent from established plots.

31 One of the groups of species analysed were those species generally associated with open habitats, several of which are of conservation concern. These are true farmland species not dependent on any woody or scrubby habitats such as hedgerows, and include Waders, Pipits, Wagtails and Skylarks. The results of this study suggest that although these species were rarely present in established SRC plots, recently planted or cutback plots may be a more attractive habitat than arable control plots. For example, in May of year 1 there was a higher density of open species in the SRC plots than the controls (F1, 11 =6.90, p<0.05). During the remainder of the study the arable control plots tended to support higher densities of open species than established SRC plots, this was significant in June of year 4 with a higher density of open species in the control plots (F1, 11 =5.95, p<0.05).

There was a higher density of Skylarks in the recently planted and cutback SRC plots than the controls during June of year 1 (F1, 11 =5.22, p<0.05). In year 1 there was also a difference in the density of Skylarks between the six recently cutback SRC plots (planted 1999) and the six recently planted plots. The difference between the recently planted plots and the cutback plots was not apparent during May, with slightly higher densities recorded in the recently planted plots. However, in June Skylarks were only recorded in the cutback plots and the difference between the two planting years was significant (F1,10 =14.48, p=0.01). The mean density of Skylarks over both visits is shown in Figure 2.16.

3 2 to

a)control b)planted c)cut-back Number of skylarks

Fig 2.16 Comparison of the total number of Skylarks per hectare from within the 6 recently planted SRC plots, 6 recently cut-back SRC plots and arable controls in year 1 of the 4-year study

32 In the last two years of the study the control plots tended to support higher densities of Skylarks than the established SRC plots. Skylarks were recorded at only two of the twelve sites once the SRC had reached more than one year of growth. The established site with the highest density of skylarks was site 7 (Shire Oaks), this was one of the sites that was gapped up in the spring one year after cutback, and contained some relatively open areas within the crop. There were no records of Skylarks in sites with more than 2 years growth (Figure 2.17).

2 "E CD

1 - PLOT ■ Control 0 a SRC 0 1 2 SRC growth (years)

Fig 2.17 Total number of Skylarks per hectare from within the 12 SRC plots at various stages of growth throughout the 4-year study period

Four species of wader were recorded as present in the SRC plots in the first year of the study; these were Lapwing, Curlew, Redshank and Oystercatcher. Although three of these species were recorded in the arable controls, only Lapwing was recorded from more than one of the arable sites (Table 2.1).

Waders also preferred recently planted and cutback SRC plots to the arable controls (Figure 2.10). In May of year 1 there were more waders in the SRC than the controls (F1, 11 =7.07, p<0.05). The density of waders within cutback plots was not significantly different from the density within recently planted plots (Figure 2.11).

In year 2 both Curlew and Lapwing were recorded on the recently cut SRC plots, although no waders were recorded on the plots that had been cut the previous year.

33 During this year numbers of waders and open species generally were too low to prove any significant difference between the SRC plots and the controls.

3 -

1 - PLOT ■ Control 0 Q SRC 1 2 SRC growth (years)

Fig 2.18 Total number of Waders per hectare from within the 12 SRC plots at various stages of growth throughout the 4-year study period (growth=0 includes both recently planted and recently cut-back SRC plots)

E to

a)control b)planted c)cut-back Number of waders

Fig 2.19 Comparison of the total number of waders per hectare from within the 6 recently planted SRC plots, 6 recently cut-back SRC plots and arable controls in year 1 of the 4-year study

34 Waders were noticeably absent from established SRC plots. In the final two years the only waders to be recorded were from site 3 (Paddock House Farm) following a recent harvesting. The record involved a total of 6 Lapwings present during May 2003. When the site was revisited in June 2003 willow had started to become established and no Lapwings were found.

2.4.9 Comparison between different age classes of SRC

Summary

Numbers of birds per hectare and the total number of species recorded per point count increased during the first two years of willow growth in the edge of the SRC. There was no increase in bird density in the interior of the crop, where numbers of birds present remained relatively low regardless of the age of the willow crop. The number of species recorded per point count was higher in the established SRC than the recently planted/cutback plots. Species composition within the crop changed with the age of the crop, with Tits, Finches and Warblers increasing in abundance with age. Thrushes reached a maximum density in 2-year-old SRC and Game birds in 1-year-old SRC. Species preferring open habitat tended to decline with increased willow growth.

The results suggest an increasing use of the SRC plots by birds as the age class of the willow crop increases. Figure 2.20 shows the total number of individual birds per hectare at various age classes for the boundary, edge and interior of the crop.

In the SRC edge the density of birds increased in relation to age class for the first two years of willow growth during May (F3,31 =5.88, p<0.01). Once the SRC was over two years old there was no change in the density of birds with increased willow growth. In the SRC interior the age of the willow crop was not a factor determining the overall density of birds that the plot supported (Figure 2.20).

For the May surveys there was also a significant increase in the total number of species recorded during each 5 minute count within the SRC edge for the first two years of willow growth (F3,31 =9.66, p<0.001). In the interior there was also a significantly higher number of species recorded during May in the established coppice, i.e. plots with at least one year's growth in comparison to recently planted and cut SRC (F1,17 =20.79, p<0.001).

35 Boundary

2 10 ! (n "2 in

Edge

2 10 03

"OC/3 CD 5

0 0 12 3 SRC growth (years)

Interior

(0 10

(n ~£. in 5

0 0 1 2 3 SRC growth (years)

Fig 2.20 Total number of birds per hectare recorded from the boundary, edge and interior during May for the 12 SRC plots at various stages of growth throughout the 4-year study period (growth 0 includes both recently planted and cut-back SRC)

36 Boundary

8 7

'o® 6

0 1 2 3 SRC growth (years)

Edge

8 1 7 -

'o® 6-

0 1 2 3 SRC growth (years)

Interior

8 1 7 -

® 6- I 5

C/3 o 43

2 1 0 0 1 2 3 SRC growth (years)

Fig 2.21 Total number of species per 5 minute point count recorded from the boundary, edge and interior of the 12 SRC plots at various stages of growth throughout the 4-year study period (growth 0 includes both recently planted and cut back SRC)

37 The bird community present within the SRC was also influenced by the age of the willow crop. The density of Tits (F3,31 =5.34, p<0.01), Finches (predominantly Chaffinch) (F3,31 =3.71, p<0.05) and Warblers (F3,31 =12.75, p<0.001) increased significantly reaching a maximum density in the third year of growth. The density of thrushes was higher in SRC in its second year of growth (F3,31 =4.83, p<0.01), and the maximum density of Game birds occurred in SRC with one year's growth (F3,31 =4.26, p<0.05). Species preferring open habitat (e.g. Skylarks and Waders) decreased with the increase in willow growth but the numbers recorded were not high enough to be statistically significant.

2.5 Discussion

This study of birds in SRC had two aims; to assess whether commercially planted and managed SRC contained similar bird communities as earlier experimental plantations, and to see if these SRC plantations displace other farmland birds.

The results of this study indicate that commercially planted SRC plots have the potential to support a higher number of bird species than the traditional arable crops they replace. In common with previous studies the SRC crop tended to support species typical of shrubby woodlands, which were mostly absent from the arable fields. This reflects the fact that SRC due to its diverse structure is essentially a woodland habitat (Sage et a!., 1994). Despite this there were some woodland species that were notably absent from the SRC plots. In particular Chiffchaffs were recorded in the boundary hedgerows but not the SRC. This species was recorded as utilising non-commercial SRC plots in a previous study (Sage et al, 1994). Although, it is perhaps not surprising that Chiffchaffs prefer trees in the boundary hedges given their preference for tall mature standard trees within traditional coppice (Cramp & Simmons, 1992; Simms, 1985). In established SRC, Willow Warblers were especially abundant. Willow Warblers are a species that have undergone population declines in the UK, despite being fairly common and are on the amber list for species of conservation concern (Gregory et al, 2002) (see table 2.2, page 44). Of the other species frequently recorded in established SRC, Reed Buntings are also of considerable conservation concern having undergone a greater than 5% contraction in their range in recent years (Chamberlain & Fuller, 2000).

The second consideration in this study of commercial SRC is the potential loss of certain species resulting in a change of land use from an arable crop to a SRC plantation. Many species associated with farmland habitat; in particular Skylarks, Yellow Wagtails, Lapwings and Grey Partridge have already declined due to changes in agricultural land use (Chamberlain & Fuller, 2000). The results of this study indicate that these species are mostly absent from established SRC plots. This is to be expected given that they are all species associated with open habitats.

However, the results suggest that recently planted and cutback SRC could potentially provide a better habitat for many of these species than arable fields. Both Skylarks and Waders (in particular Lapwings) were more abundant in recently established and cutback SRC than the arable fields. Both Skylarks and Lapwings are of

38 conservation concern (Gregory et al, 2002) (see table 2.2, page 44). There were some differences noted between the recently planted plots and the harvested plots. This may reflect the fact that recently harvested plots have some established weed growth, which could provide a source of food and cover for some bird species but be unsuitable for other species (Sage & Tucker, 1998). The value of cut SRC for birds may change rapidly with the increase in willow coppice and weeds during the summer after cutback. Skylarks for example appeared to show a preference for plots that had recently been cut after one year's growth to recently planted plots in June, but no particular preference between the two plots during May.

The density of birds found within the commercially planted SRC plots monitored during this study was much lower than previously recorded within SRC. Although it is only possible to speculate this could be due to a number of differences that exist between commercially managed SRC plots and the type of plots used in previous studies. For example, the plots monitored in this study tended to be of greater size than previous studies, with less edge to area ratio. The smaller plots previously studied would therefore had provided a greater juxtaposition of different habitats favoured by many species of birds (Loman & von Schantz, 1991). The commercial plots used in this study had higher inputs of fertilisers and herbicides than the previously studied experimental plots. The commercial plots could therefore contain fewer weeds and fewer invertebrates than the previously studied plots and consequently support a lower density of birds.

In this present study the established SRC supported higher densities of birds at the edge of the crop than the middle. In recently established SRC this edge effect was not generally noticeable, although one particular group of species (Robins, Dunnocks and Wrens) were only recorded in the edge and boundaries of the recently established SRC.

The mean density of birds within established SRC in this study was 3.4 birds per hectare. In comparison, Kavenagh (1990) calculated a density of 8.6 breeding pairs of birds per hectare on willow coppice on peatland in Ireland using a similar point count method. In a more recent study, the number of breeding pairs of birds per hectare in willow SRC ranged from 4.2 following harvest (year 0) to 13.8 in willow with two years growth (Sage et al, 1994).

The density of birds within the SRC plots was higher than that found within the arable controls. In this present study the mean density of birds within the arable control plots was 0.8 birds per hectare. These results were not too dissimilar to those recorded elsewhere. Arnold (1983) recorded a density of 1.3 birds per ha in cereal fields surrounded by mature hedgerows, and Fuller, Gough & Merchant (1995) recorded songbird densities of 0.2 birds per ha in open farmland.

The hedgerows and boundary habitat surrounding established SRC plots also tended to support a higher density of birds and be more species rich than the arable control boundaries. This suggests that the benefit provided by planting willow coppice extends beyond the boundary of the crop area.

39 The extent to which species utilised the SRC and the boundary hedgerows varied between the different bird groups. Migrant warblers were equally abundant in the established SRC edge as in the boundaries, whereas many Resident species were more abundant in the hedgerow boundaries than the SRC edge. Migrant warblers have previously been found to be more associated with woodland than hedgerows (Fuller et ai„ 2001), and the results from this present study suggest that for this group of birds the SRC represents a suitable habitat. However, it is worth noting that migrant warblers recorded during this study were dominated by one species, the Willow Warbler and that some species notably whitethroat were more frequently recorded in the hedgerows.

The density of songbirds in traditional coppice woodland has been shown to vary with the age of the coppice (Fuller & Henderson, 1992). A previous study into bird communities within SRC has shown that willow in its third year of growth contains more birds than younger or older willow (Sage et al, 1994). This finding is supported by the results from this study, which show the density of birds increasing at the edge of the SRC plots for the first two years of growth, although there was no difference between 2 year old and 3 year old willow coppice. The number of species recorded per point count also increased for the first two years of growth in the SRC edge and during the first year of growth in the middle of the SRC. The increase in species with age within SRC has been previously documented, with the number of species recorded within the crop being positively associated with the height of the plantation (Berg, 2002).

The species composition within the SRC was found to change with growth of the willow coppice. Tits, Finches and Warblers were all found to increase in abundance for the first three years of willow growth. Sage etal. (1994), found that both Tits and migrant Warblers increased in abundance in the three years following establishment of the SRC crop, although they also documented recently cut coppice to be preferred by finches. A similar pattern was also found in traditional coppice woodland. In the present study thrushes were found to prefer two year old SRC and game birds one year old SRC. Sage etal. (1994) found that pheasants tended to be more abundant in one or two year old SRC.

40 2.6 References

Aebischer, N.J., Evans, A.D., Grice, P.V. & Vickery, J.A. (1999) Ecology and Conservation of Lowland Farmland Birds. 1999 British Ornithologists' Union Spring Conference.

Arnold, G.W. (1983). The influence of ditch and hedgerow structure, length of hedgerows and area of woodland and garden on bird numbers in farmland. Journal of Applied Ecology. 20: 731-750.

Baillie, S.R., Crick, H.Q.P., et al. (2001) Breeding Birds in the Wider Countryside; their Conservation Status (2000). BTO research report no. 252. British Trust for Ornithology, Thetford, Norfolk. Berg, . (2002) Breeding birds on short rotation coppices on farmland in central Sweden-the importance of Salix height and adjacent habitats. Agriculture, Ecosystems & Environment. 90 (3): 265-276.

Bibby, C.J., Burgess, N.D. & Hill, D.A. (1992) Bird Census Techniques. Academic Press Limited, London.

Chamberlain, D.E & Fuller R.J. (2000) Local extinctions and changes in species richness of lowland farmland birds in England and Wales in relation to recent changes in agricultural land-use. Agriculture, Ecosystems & Environment. 78 (1): 1 17.

Cramp, S. & Simmons, K.E.L. (1992) Handbook of the birds of Europe, the Middle East and North Africa: the birds of the western Paiaearctic. Volume 6, Warblers, Oxford University Press, Oxford.

Fuller, R.J., Chamberlain D.E., Burton N.H.K. & Gough, S. J (2001) Distributions of birds in lowland agricultural landscapes of England & Wales: How distinctive are bird communities of hedgerows and woodland? Agriculture, Ecosystems & Environment. 84 (1): 79-92.

Fuller, R.J., Gough, S.J. & Marchant, J.H. (1995) Bird populations in new lowland woods: landscape, design and management perspectives. In: Ecology of New Woodland. Belhaven Press.

Fuller, R.J. & Henderson, A.C.B. (1992) Distribution of breeding songbirds in Bradfield Woods, in relation to vegetation and coppice management. Bird Study 39: 73-88.

Goransson, G. (1990) Energy foresting in agricultural areas and changes in the avifauna. Proceedings of the Sixth Nordic Congress of Ornithology, pp 17-20. Roros, Norway.

41 Gregory, R.D., Wilkinson N.I., Noble D.G., Robinson J.A., Brown A.F., Hughes J. Procter, D.A., Gibbons D.W. & Galbraith C.A. (2002) The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002-2007. British Birds 95: 410-450.

Kavenagh, B. (1990) Bird communities of two short rotation forestry plantations on cutover peatland. Irish Birds 4: 169-180.

Loman, J & von Schantz, T. (1991). Birds in farmland- more species in small than large habitat island. Conservation Biology. 5: 176-188.

Sage, R.B. & Robertson, P.A. (1994) The wildlife and game potential of short rotation coppice in the UK. Biomass and Bioenergy. 6: 41-48.

Sage, R.B. & Robertson, P.A. (1996). Factors affecting songbird communities using short rotation coppice habitats in spring. Bird Study. 43: 201-213.

Sage, R.B, Robertson, P.A. & Poulson J.G. (1994) Enhancing the conservation value of short rotation biomass coppice- Phase 1 the identification of wildlife conservation potential. Report of the Energy Technology Support Unit, Department of Trade and Industry.

Simms, E. (1985) British Warblers. Collins, London.

Spellerberg I. (1991) Monitoring ecological change. University Press, Cambridge.

Weins, J. A. (1989) The Ecology of Bird Communities. Cambridge University Press, Cambridge.

42 2.7 Appendix 2000 2001 2002 2003 Species Control SRC control SRC Control SRC control SRC Barn Owl 0 0 1 0 0 0 0 0 Blackbird 9 2 5 7 8 11 3 11 Blackcap 2 2 2 4 3 1 0 5 Blue Tit 2 5 4 5 6 12 3 11 Bullfinch 0 0 0 0 0 0 0 1 Chaffinch 11 10 6 7 8 10 7 12 Chiffchaff 1 1 0 0 0 0 0 5 Corn Bunting 1 1 2 2 0 0 0 0 Curlew 0 4 1 3 1 0 0 0 Dunnock 8 6 0 5 0 4 1 4 Garden Warbler 0 1 0 0 0 0 0 0 Goldfinch 1 1 2 5 1 3 1 0 Great Tit 3 8 4 4 5 6 2 9 Greenfinch 2 1 1 1 4 1 2 0 Grey Partridge 0 0 0 1 0 0 0 0 House Martin** 1 1 1 1 1 1 0 0 House Sparrow 1 5 0 0 2 0 0 0 Lapwing 3 8 5 2 4 1 2 1 Lesser Whitethroat 0 0 0 0 0 1 0 0 Linnet 0 2 1 1 4 2 5 1 Long tailed Tit 0 0 0 1 0 0 0 7 Mallard 0 1 1 1 0 0 0 0 Magpie 1 1 0 1 0 5 0 1 Marsh Tit 0 0 0 1 0 0 0 0 Meadow Pipit 0 0 0 1 0 2 0 1 Moorhen 0 1 0 1 0 0 0 0 Oystercatcher 0 4 0 1 0 0 0 0 Pheasant 2 3 0 2 2 6 2 7 Pied Wagtail 1 3 0 1 0 0 0 0 Red legged Partridge 2 1 0 3 3 1 1 0 Redshank 0 1 1 0 0 0 0 0 Reed Bunting 1 0 0 1 4 2 1 4 Reed Warbler 1 1 0 0 0 1 0 0 Robin 6 3 4 8 0 1 2 3 Sedge Warbler 0 0 0 0 0 0 0 0 Shelduck 0 0 0 0 0 0 1 0 Skylark 10 11 9 10 9 2 10 3 Song Thrush 3 1 1 1 0 1 0 3 Starling 0 0 1 1 4 4 0 0 Stock Dove 1 0 1 0 1 0 0 0 Swallow*** 6 5 3 3 9 7 0 0 Tree Sparrow 0 0 0 0 0 1 0 0 Turtle Dove 0 1 0 0 0 0 1 0 Whitethroat 1 4 3 7 3 6 6 7 Willow Warbler 4 3 4 8 6 11 3 10 Wood Pigeon 1 1 0 0 1 3 0 1 Wren 8 7 6 9 5 10 3 1 Yellowhammer 8 8 6 7 4 4 6 6 Yellow Wagtail 2 1 2 1 4 1 3 1 Table 2.1 Number of sites individual species recorded during each year of the study, numbers in bold indicates that the species was recorded only within the boundary. ** species recorded in flight only

43 Species Presence Conservation Status Bullfinch Red ++ Corn Bunting Red Grey Partridge * Red House Sparrow Red Linnet Red + Marsh Tit* Red ++ Reed Bunting Red ++ Skylark* Red Song Thrush Red Starling Red Tree Sparrow Red Yellowhammer Red ++ Barn Owl * Amber + Curlew* Amber ++ Dunnock Amber ++ House Martin Amber Lapwing* Amber Meadow Pipit Amber ++ Oystercatcher* Amber ++ Stock Dove Amber + Swallow Amber Willow Warbler Amber ++ Yellow Wagtail Amber +

Table 2.2 Conservation status of birds recorded during summer visits to SRC and arable plots (from RSPB, 2000). Red list species are those with a rapid (more than 50%) decline in the UK breeding population over the last 25 years. Most of the Amber listed species are those that have experienced a moderate decline (25-49%) in the UK breeding population in the last 25 years. Oystercatchers, Curlews and Stock Doves are amber listed due to the UK having more than 20% of the European breeding population.

Presence ++ more frequently recorded in SRC than arable controls + more frequently recorded in arable controls than SRC * = Species not recorded in established SRC (>1 years growth)

NB. Lapwing and Skylark although overall more abundant in arable controls than SRC, were more abundant in recently established SRC than arable crops

44 3. VEGETATION WITHIN SRC AND ARABLE PLOTS

3.1 Summary

Vegetation was sampled within a 1 x 10 metre quadrat at various distances from the crop edge along transects within SRC willow plantations and arable control fields. The vegetation of SRC and arable headlands within 1 x 10 metre quadrats was also monitored. The SRC and arable control plots were monitored each summer over a four year period. This enabled the vegetation community of commercial SRC plantations to be compared to that of the previous land use i.e. arable fields. Each individual species was recorded using the DAFOR scale (see Table 2.1) to give an indication of relative abundance. Plant species were categorised into annuals, short lived perennials and long-lived perennials to monitor plant succession occurring during the production cycle of commercial SRC plots. The overall amount of vegetation cover was also estimated.

Over the four year period a total of 133 species of plants were recorded from the SRC plots and headlands, compared to 97 species in the arable plots and arable headlands. The SRC were more species rich than the arable plots during each year of the study. Most species present in the arable plots were annuals; characteristic of disturbed land with Cleavers Galium aparine, being the most frequently recorded species. Most of the species recorded in recently planted SRC were also annuals, but vegetation cover was higher than in the arable controls, where closely planted monocultures limited the spread of non-crop species.

The number of species within the SRC increased in the first year and the number of species with a greater than 10% cover increased with each successive year of willow growth. The number of grass species within the SRC also increased in the first year and then declined as the SRC became more established. The number of grass species with greater than 10% cover increased for the first two years of SRC growth and declined, mostly due to the increasing dominance of species like Yorkshire Fog Holcus lanatus, and within the headlands Cocksfoot Dactylis glomerata and False Oat Grass Arrenatherum elatius. The number of species within the SRC headlands declined in subsequent years following establishment.

Vegetation cover increased in the first year and then remained fairly constant, although some SRC plots were almost devoid of other plants whereas others had an almost continuous ground cover. Vegetation cover increased more rapidly at the edge of the SRC plots than in the middle of the plot, suggesting colonisation from the surrounding headlands or better survival of existing plants with higher levels of light. In young SRC there was a recognisable edge effect with higher vegetation cover 1 metre from the edge than 4 metres.

The established SRC plots had a lower proportion of annual species and a higher proportion of short-lived and long-lived perennial species than the arable controls. The results also indicate a succession towards both more invasive perennials and stable perennial species within the young SRC plots over the period of the study. In

45 the plots planted in 1999 there was a significant decline in the proportion of annual species over the period of the study. Many annual species were absent or recorded only as rare (less than 5% cover) on the DAFOR scale. Whereas perennials such as Creeping Buttercup Ranunculus repens. Broad-leaved Dock Rumex obtusifolis and Yorkshire Fog were recorded more frequently and at higher amounts of percentage cover in more established SRC plots.

3.2 Introduction

Short-rotation coppice (SRC) may become a widespread crop replacing traditional arable crops in the UK (DTI, 1994). The planting of perennial SRC plots results in shadier and more stable conditions than those found in the arable crops that they replace (Sage, 1995). In contrast to most arable crops, SRC are only harvested every 2-4 years enabling a cover of ground vegetation to become established (Sage et a!., 1994). Herbicide application is normally limited to one application before planting and after initial cutback after one year's growth (Clay, 1996). The shadier and more stable conditions within SRC plots are likely to result in a different plant community structure than that normally found within other arable crops (Sage, 1995). An established ground flora community that doesn't compete with the crop or interfere with harvesting is to be encouraged and may provide many benefits (Sage & Tucker, 1998).

Areas of ground vegetation will support predatory ground beetles and spiders (Forsythe, 1987). The abundance of Blue Willow Beetle Phyllodecta vulgatissima found during invertebrate monitoring carried out during this study (section 6.0) highlights the importance of retaining ground vegetation to provide a suitable habitat for natural agents of pest control. A cover of ground vegetation may also be important for nesting birds, including Pheasants providing additional income to growers with a shooting interest (Sage et al, 1994). An adequate covering of ground vegetation can also consolidate the soil, provide a landscape benefit and increase biodiversity by providing nectar sources for many species of insects including butterflies and parasitic hymenoptera (Sage & Tucker, 1998).

The plant community within SRC plots has already been shown to undergo succession over time, with slower growing perennials tending to replace annual species (Sage, 1995). This study provides a further opportunity to compare the plant community changes occurring over a four-year period within commercially planted SRC plots.

The use of arable control plots in this present study allows the plant community of SRC plots to be compared to other arable plots. It is therefore important to document any changes in plant species that occur as a result of converting arable land to SRC as many arable weeds species are of conservation concern (Wilson, 1992). Although some species are problematic, it has been recognised that many arable weeds actually cause little reduction in crop yield and contribute to species diversity in the arable landscape (Albrecht, 2003).

46 In this study the plant community found within SRC and arable headlands is compared to the plant community found within the crop. Although the plant community of SRC headlands largely reflects that found within the crop itself some differences in species composition has been recognised (Sage et al, 1994). Monitoring headlands within the arable control plots allows comparisons to be made between these and the SRC headlands to be examined throughout the period of the study.

The present study also involves recording plants species present at various distances into the crop from the edge. The ability to colonise or survive the interior of arable plots may vary between species (Wilson & Aebischer, 1995; Marshall, 1989). Some species tend to be more associated with the edge of SRC plots, whereas other species tend to increase in abundance with increased distance from the edge (Sage et al, 1994). The plant community found within SRC plots may therefore be influenced by the extent of the edge habitat. An understanding of the edge effect on plant communities within SRC is important if the value of the wildlife habitat is to be maximised.

Bare ground is a common feature in SRC plots (Sage et al, 1994), although it may be less attractive to wildlife than a cover of vegetation. Whether or not there is a correlation between distance from the crop edge and percentage vegetation cover is another question that can be addressed by this study. Surveying the same plots over a four-year period also allows any changes in the extent of vegetation cover to be monitored.

3.3 Methods

3.3.1 Methodology used in recording vegetation in SRC and arable plots

Plants were monitored within each of the twelve SRC plots and their paired arable control plots once during the summer (end of June to mid-July) for each year of the study. Two transects were sampled in each of the SRC and control plots, running from the edge of the plot into the crop. Where possible the two transects were situated at opposite ends of the plots. The positioning of transects within the arable plots was restricted to tramlines to prevent any potential damage to the crop. The direction of tramlines also dictated the starting edges within the arable plots. The position of transects remained constant throughout the four-year period of the study to allow direct comparison to be made between years.

Each transect contained six 10m x 1m quadrats at various distances from the plot edge, one in the headland, one just inside the crop and then at 4m, 15m, 60m and 100m into the crop. In plots without any headland present only five quadrats were sampled, starting just inside the crop. Each quadrat was placed parallel to the starting edge to ensure sufficient spacing between them and to reduce potential variation within the quadrat with respect to the distance from the crop edge.

47 The large quadrat size was considered necessary in order to sample the potentially sparse vegetation cover within the crop. A list of all plant species recorded within each transect was compiled. The relative abundance of each species present was also estimated using a DAFOR scale based on percentage cover as shown below (Table 3.1). Each DAFOR rating was given a numerical value that was entered in the database.

DAFOR DAFOR score Percentage Cover Dominant 5 >50% Abundant 4 25 - 50% Frequent 3 10 - 25% Occasional 2 5 - 10% Rare 1 <5%

Table 3.1 The DAFOR system used to estimate abundance of each species within the survey quadrats.

The percentage total vegetation cover was also recorded for each quadrat. In addition to the two transects a further two 10 m x 1m quadrats were surveyed within the headland of each plot. This was done to compensate for the lower number of quadrats sited in the headlands than within the crop.

3.3.2 Data analysis

A number of variables were used in the analysis: number of plant species; number of grass species and percentage vegetation cover. Each species was classified according to their main establishment strategy (after Grime et al., 1988). The three categories used were a) annual species or those able to propagate from buried fragments e.g. Couch grass Elymus repens b) Short-lived perennials (invasive perennials characteristic of disturbed habitats) e.g. Common Nettle Urtica urens. c) Long-lived perennials (perennial species characteristic of stable habitats e.g. Yorkshire Fog. A list of plant species recorded with the appropriate categories are shown in Table 3.2 at the end of this section. From the number of species recorded within each of these categories, the proportion of total species belonging to each of these categories was calculated enabling differences in plant community between SRC and arable controls and SRC of different age classes to be considered.

In order to allow analysis to be carried out percentage and proportional variables were arcsine transformed to normalise the distribution and standardise the variance. The remaining variables were transformed to approximate a normal distribution using log (x+1).

The means of each of the above variables was calculated for each plot at each of the distances into the crop. Data was entered into SYSTAT statistical package and analysed using general linear modelling.

48 3.4 Results

3.4.1 Species List within SRC and arable control plots

Summary

A higher number of plant species were found in the SRC plots than the arable control plots over the four year study period. The limited opportunities for plant species to establish within the arable fields meant that most species were recorded at less than 5% cover. Most species on the arable fields were annuals, with Cleavers being the most frequently recorded. The recently planted SRC plots were dominated by bare ground, with most species being annuals characteristic of disturbed ground. The cutback plots still contained a high proportion of annual species but vegetation cover was higher than in the recently established plots. A number of annual species were missing or were only rare in the established SRC plots, suggesting a succession towards more stable perennial species. The most abundant species within the established SRC were Yorkshire Fog, Creeping Buttercup and Creeping Thistle Cirsium arvense.

A total of 133 species of plant were recorded from the SRC plots throughout the four-year study period. Out of these 26 species were recorded as present only in the headlands. In the control plots a total of 97 species of plant were recorded. A full species list of plants recorded in the SRC and arable control plots is given in Table 3.2. Three species were particularly characteristic of the SRC plots, being present in more than 75% of the sites throughout the study. These were Yorkshire Fog, Creeping Buttercup and Creeping Thistle. In the arable control plots only Cleavers occurred in more than 75% of the sites on average.

Of the 97 species recorded in the arable plots only 13 were recorded at more than 5% cover actually within the crop. Many species that did occur in the control plots had spread from the surrounding headland. Eight of the species occurring with greater than 5% cover were restricted to within 1m of the crop edge. A total of 14 species were recorded as present from more than 3 arable control plots. Out of these 6 species were grasses; these were Barren Brome Bromus sterilis, Couch Grass Elymus repens Annual Meadow Grass Poa annua, Cocksfoot Dactylis glomerata. Rye Grass Lolium spp, and Foxtail Alopecurus spp. The remaining species were all annuals associated with disturbed ground. The most frequently recorded of these was Fat hen Chenopodium album, Chickweed Stellaria media and Scentless Mayweed Tripleurospermum inodorum.

Within the SRC higher numbers of species were found in established plots in comparison to recently planted plots, where bare ground dominated. In the first year of the study (year 1) the six recently planted plots contained only 11 species. The majority of these species were annuals and short-lived perennials characteristic of disturbed land. Mean vegetation cover in these plots was only 8.57% and no species were recorded as abundant. The only species recorded at more than 10% cover was Yorkshire Fog.

49 In contrast, a total of 69 species were recorded from the six plots that had recently been cut-back after one year's initial growth. Seven of these species were recorded as abundant or dominant, three grasses, Meadow Foxtail Alopecurus pratensis, Smooth Meadow Grass Poa pratensis and Couch grass Elymus repens, and four characteristic of recently disturbed land, Groundsel Senecio vulgaris. Scentless Mayweed, Common Orache Atripiexpatuia and Creeping Thistle. Vegetation cover within these plots was still comparatively low, with a mean cover of 11.6%.

Out of the total number of species recorded within the SRC, 110 were recorded within the established plots. The number of species recorded varied from 86 species in year 2 of the study to 68 species in the final year (year 4) of the study. Out of these only 13 species were recorded as abundant or dominant. Of these 7 species were grass species, with the most frequently recorded being Rough Meadow Grass Poa triviaiis and Yorkshire Fog. Of the remaining vascular species recorded as abundant the two most frequently recorded species were Creeping Buttercup and Creeping Thistle.

Four species of annual plants recorded on recently planted and cut-back SRC were not found in the established plots. These were Pineapple Weed Matricaria discoidea, Shepherds Purse Capseiia bursa-pastoris, Chickweed and Common Poppy Papaver rhoeas. Three of the species recorded as abundant in young SRC plots Scentless Mayweed, Groundsel and Common Orache were not recorded as more than frequent in the established SRC plots. This suggests that species characteristic of disturbed ground are being replaced by a more stable plant community.

3.4.2 Comparison between numbers of plant species present within SRC and arable control plots

Summary

The results show that established SRC provides a greater opportunity for a more diverse community of plant species to become established than more conventional crops. The number of species within recently established SRC plots (year 1) did not differ from the other arable plots. SRC plots cutback after one years growth (plots planted 1999) were more species rich than the recently planted plots (planted 2000). The established SRC plots were more species rich than the arable controls. The headlands of both the SRC plots and arable control plots were more species rich than the plots themselves. The headlands of SRC plots tended to contain more species than the headlands of conventional crops. SRC plots that had been established for 2 or 3 years (those surveyed in 2002) contained more grass species than the arable plots.

The number of plant species recorded per quadrat within the SRC plots varied significantly between survey years (F3,31 =10.92, p<0.001). The mean number of species within the SRC (excluding headlands) ranged from 3.7 in the recently planted and cutback plots of year 1, to a maximum of 7.5 in year 2. In contrast, the

50 mean number of species within the arable controls (excluding headlands) did not vary between survey years, with an average of 3.6 species per quadrat over the four- year study period.

In year 1 there was no difference between the arable controls and the recently established SRC plots. The six plots cut back after one year of growth (planted 1999) contained more plant species than the six recently planted plots (planted 2000) during this year (F1,10 =9.13, p<0.05). In year 2 there tended to be more species within the SRC plots than the arable controls although the difference was not quite significant. However, the SRC was significantly more species rich than the arable controls in year 3 (F1,11 =55.20, p<0.001) and year 4 (F1,11 =15.12, p<0.01) (Fig 3.1).

The SRC headlands tended to be more species rich than the headlands of the arable controls. The SRC contained an average of 11.24 species per quadrat, compared to an average of 9.98 species in the controls. The difference between the SRC headlands and control headlands was significant in year 4 of the study (F1,10 =10.50, p<0.01) (Fig 3.1).

Fewer species of plants were found within the SRC plots than the SRC headlands in year 1(F1,11 =29.85, p<0.001), year 2 (F1,9 =28.34, p<0.001) and year 3 (F1,11 =82.91, p<0.001). In the final year the SRC headlands contained less species than in previous years, and were consequently no more species rich than the SRC crop. There were significantly more species in the headlands of the arable plots than within the crop during each year of the study (Fig 3.1).

Within the SRC plots the number of grass species recorded per quadrat also varied between survey years (F3,31 =25.35, p<0.001). The average number of grass species recorded per quadrat in the SRC ranged from 1.1 species in year 1 to a maximum of 3.1 species in year 2. In contrast, the number of grass species within the arable control plots remained relatively constant throughout the study, with an average of 1.6 species per quadrat. There were significantly more grass species recorded within the SRC crop than the other arable crops in year 3 of the study (F1,11 =37.01, p<0.001).

There were less species of grass within the SRC crop that the SRC headlands in year 1 (F1,11 =84.48, p<0.001), year 2 (F1,9 =35.50, p<0.001) and year 3 (F1,11 =23.56, p=0.001), (Figure 3.2).

51 1 Total no. of species Total no. of species Total 20- 25 15 and

within number

the of

SRC plant 0 ■

PLOT and

control SRC

species

arable

per

crops (Z) (Z) (Z) o ro C 0 o 0 52 l

1m 25

during x

10m

quadrat each 2001 2003

year

both of

the in

the

study

headlands

Fig

3.2 Total no. of grass species Total no. of grass species

Total 10r 10 and 6- 2 4 6 8 0 8

within number

the 2000 2002

SRC grass 0 ■

PLOT and

control SRC

species

arable

per

crops O) 2 &

1m 10 10 2 4 6 8 0 8

during x

10m

each quadrat 2001 2003

year

both

the in

the study j

headlands 3.4.3 Effect of distance from the crop edge on numbers of plant species

Summary

In the first two years of the study there was an edge effect in terms of the number of species recorded within the SRC plots. In both years 1 and 2 there were more species 1 metre from the edge than 4 metres from the edge. This was probably due to colonisation from the surrounding headlands or better survival of existing plants with the higher light levels. In the last two years there was no noticeable edge effect in terms of species present.

In the first two years of the study the edge of the SRC was more species rich than the interior. A higher number of species were found at 1 metre from the SRC edge than 4 metres into the SRC both in year 1 (F1,11 =55.10, p=0.001) and year 2 (F1,9 =14.66, p=0.01). There was no change in the number of species with further increasing distances into the crop beyond 4 meters from the edge (Figure 3.3). In the last two years of the project there was no relationship between the number of plant species found and distance from the edge (Figure 3.4).

There was also no relationship between the numbers of grass species and distance from the edge of the crop either in the SRC plots of the arable control plots (Figure 3.5 and Figure 3.6).

3.4.4 Changes in the number of species present within SRC plots with increased SRC growth

Summary

In the first year of establishment there was an increase in both the total number of species and the total number of grass species within the SRC plots. After one years growth there was no change in the number of species recorded, although the number of grass species declined. The number of species with a greater than 10% cover continued to increase for the three year growth cycle of the SRC plots. The number of grass species with more than 10% cover increased for the first year or two of establishment before declining later in the growth cycle as fewer more competitive species became increasingly abundant. The number of species in the SRC headlands declined in the four years following establishment. The numbers of species with greater than 10% cover within the SRC headlands increased for the first year or two before declining as more competitive species began to dominate.

The number of species within the SRC plots tended to increase in the first year after planting. This was significant for the plots planted in 2000, with the number of species increased both at the edge (4 metres or less into the crop) (F1,8 =5.80, p<0.05) and in the SRC interior (F1,8 =12.86, p<0.01) (fig 3.7).

54 2000

25 r $ % 20 Q. CZ) o 15 0 _Q 10- 3 C B 5- o 01——1

2001

Fig 3.3 Total number of species recorded per 1mx10m quadrat at increasing distance from the crop edge during the first two years of the study (2000 and 2001)

55 distance Fig

3.4

Total number of species Total number of species from Total 20 25 20 25 10 15 10 15 0 5 0 5

the number

crop ■ a PLOT

edge of control SRC

species 2003 2002

during

recorded

year 56

(2002)

per

1mx10m

and

year

quadrat

(2003) at

of increasing

the

study

10 PLOT g o ■ SRC 0 8 Q. a control 0 0 0 6 2 O)

0 .Q

2000

10 g o 0 8 Q. 0 0 0 6 2 O) 4 0 _o 2

2001

Fig 3.5 Total number of grass species recorded per 1mx10m quadrat at increasing distance from the crop edge during year 1 (2000) and year 2 (2001) of the study

57 10 PLOT g o ■ SRC 0 8 Q. a control 0 0 CZ) 6 2 O)

X)0

2002

10 g o 0 8 0Q. 0 0 6 2 D) 4 0 _o 2

2003

Fig 3.6 Total number of grass species recorded per 1mx10m quadrat at increasing distance from the crop edge during year 3 (2002) and year 4 (2003) of the study

58 25 (Z) 0 20 Cl o 15 0

SRC growth (yrs)

a) crop edge (up to 4m into crop)

SRC growth (yrs)

b) Crop interior (>15m into crop)

Fig 3.7 Total number of species per 1mx10m quadrate within SRC plots at various stages of growth at a) the crop edge and b) the crop interior

59 There was no increase in the number of plant species after the first year of SRC growth. However, there was an increase in the number of species recorded with a greater than 10% cover during the first three years SRC growth. This was significant for the plots planted in 2000 at both the edge (F2,12 =133.83, p<0.001) and interior (F2,12 =28.97, p<0.001). It was also significant at the crop edge for the plots planted in 1999 (F3,15 =8.86, p=0.001). Within the interior of the 1999 plots the number of species with a greater than 10% cover declined one year after cutback (F1,8 =5.80, p<0.05) and then increased with further SRC growth (F2,9 =7.18, p<0.05).

Within the SRC plots there was an increase in the number of grass species in the first year of growth and then a decline as the SRC became more established. In the 1999 plots this was significant both in the crop edge (F3,15 =4.62, p<0.05) and in the crop interior (F3,15 =4.34, p<0.05). There was also an increase in the number of grass species in the interior of the 2000 plots for the first year of growth followed by a decline with further growth (F2,12 =4.62, p<0.05).

The number of grass species with greater than 10% cover within the SRC plots increased in the first year or two of establishment before declining as more dominant species became established. In the 1999 plots the number of grass species with a greater than 10% cover increased in the first two years after initial cutback and then declined both at the edge of the SRC plots (F3,15 =8.02, p<0.005) and in the SRC interior (F3,15 =3.41, p<0.05). In the interior of the 2000 plots the number of grass species with a more than 10% cover increased for the first year of growth and then declined (F2,12 =4.62, p<0.05).

The number of species within the SRC headlands tended to decline over the period of the study. This was significant for the plots planted in 1999 (F2,16 =9.11, p<0.005). However, the number of species with a greater than 10% cover tended to increase for the first year or two of establishment. In the 2000 plots there was an increase in numbers of species with more than 10% cover for the first two years of establishment followed by a subsequent decline (F3,9 =10.25, p<0.005). In the 1999 plots the number of grass species with more than 10% cover increased for the first year and then declined (F2,12 =14.16, p=0.001).

60 0 12 3 SRC growth (yrs)

a) crop edge (up to 4m into crop)

5 o

0 12 3 SRC growth

b) crop interior (>4m into crop)

Fig 3.8 Total number of species that were recorded per 1m x 10m quadrat with a greater than 10% cover within SRC at various stages of growth at a) the crop edge and b) the crop interior

61 0 12 3 4 No. of yrs established

Fig 3.9 Total number of species and total number of grass species recorded per 1m x 10m quadrat with a greater than 10% cover in SRC headlands over the four years establishment of the 12 plots

62 3.4.5 Differences in vegetation cover in SRC and control plots at various distances from the edge of the crop

Summary

Vegetation cover was higher in the SRC than the controls during every year of the study. The conditions within the arable control plots provided little opportunity for establishment of non-crop species. Vegetation cover in the SRC plots increased over the period of the study at every distance from the crop edge sampled. However the increase in vegetation cover over time tended to be more pronounced at the edge of the crop than in the interior. Vegetation cover within the SRC varied between individual plots, with some plots still dominated by bare ground even several years into the production cycle.

Vegetation cover within the SRC increased during each year of the study. In the recently planted and cutback plots of year 1 there was an average of 10% vegetation cover. In the final year of the study (2003) there was an estimated 45% average vegetation cover. In contrast, the arable crops were dominated by the crop with very little bare ground and an average of 2.5% non crop vegetation cover (excluding plots used as set aside) throughout the four years.

Despite being dominated by bare ground the recently established SRC plots (surveyed in year 1) still contained more non-crop vegetation cover than the arable controls (F1,11 =5.93, p<0.05). The vegetation cover within the SRC plots continued to be significantly higher than that of the controls throughout the remaining three years of the study.

Vegetation cover within the SRC plots varied considerably between individual sites. Site 3 (Charity Farm, Goole Fields) had the lowest mean vegetation cover during the four-year study (12%). In contrast, Site 6 (Storwood) had consistently the highest mean vegetation cover during the study (47%).

Throughout most of the study there was very little difference in vegetation cover between the SRC headlands and the headlands of the other arable plots. The exception was in year 3 when there was a higher cover of vegetation in the SRC headlands (F1,11 =6.34, p<0.05).

The results indicate that the increase in vegetation cover within SRC plots over the period of the study occurred at all distances from the edge. The extent of this increase tended to depend on the distance from the crop edge, with the highest increases occurring less than 15 metres from the edge.

In year 1 there was no difference in the extent of vegetation cover between the various distances from the crop edge. Bare ground dominated within the plots, although there was significant more vegetation cover in the headlands than 1 metre into the crop (F1,11 =94.30, p<0.001) (Figure 3.10).

63 10 % vegetation cover % vegetation cover Percentage 100 100 during

year

vegetation PLOT

2001 1

(2000)

cover

and 64

year at

increasing

j 2

(2001)

of distance

the

study

from

the

crop

edge

In year 2 there was still significantly more vegetation cover in the SRC headland than 1 metre into the crop (F-,,9 =55.77, p<0.001), although there was now a difference in vegetation cover within the crop edge, with significantly more vegetation cover at 1 metre into the crop than at 4 metres (F1,9 =28.78, p<0.001). During this year vegetation cover beyond 4 metres into the crop remained similar regardless of distance from the crop edge (Figure 3.11).

In year 3 and year 4 there was a more gradual decline in vegetation cover with increasing distance from the edge. Vegetation cover was still higher at 1 metre from the edge of the SRC than 4 metres both in year 3 (F1,11 =10.82, p<0.01) and year 4 (F-,,11 =28.61, p=0.001). However, there was now more vegetation cover at 4 metres from the edge of the SRC than 15 metres both in year 3 (F1,11 =5.02, p<0.01) and year 4 (Fi,ii =6.52, p<0.01). There was a slight decline in vegetation cover beyond 15 metres from the edge in year 4 although this was not significant (Figure 3.11).

65 1 % vegetation cover % vegetation cover Percentage 100 100 20 40 60 80 0 during

year

vegetation PLOT

2003 3

(2002)

cover

and 66

year at

increasing

j 4

(2003)

of distance

the

study

from

the

crop

edge

3.4.6 Changes in plant species composition and extent of vegetation cover with increased SRC growth

Summary

The SRC plots had a lower proportion of annual species than the controls. Established SRC plots also had a higher proportion of short-lived invasive perennial species and long-lived stable perennial species than the control plots. In the 1999 plots the proportion of annual species declined significantly over the four year study period indicating a succession towards a more stable plant community. Several annual species were rare or absent within established SRC plots, whereas many perennials were recorded at higher domin values indicating an increase in the ground cover occupied by these species as the SRC becomes established. Overall vegetation cover within the SRC plots increased following establishment for the first year and then remained fairly constant throughout the remainder of the study.

The plant community within SRC plots was different from that of the arable control plots. The proportion of annual species was higher in the arable controls than it was in the SRC plots in year 1 (F1,11 =5.86, p<0.05), year 2 (F1i9 =7.79, p<0.05) and year 4 (F1,11 =58.83, p<0.001). In year 3 although there was no overall significant difference, the more established plots (planted 1999) had a lower proportion of annuals than the control plots (F1,4 =25.02, p<0.01). In the first two years there was a tendency for the SRC plots to contain a higher proportion of short-lived invasive perennial species than the controls although the difference was not significant. In year 3, the arable control plots supported a lower proportion of short-lived perennials than both the 1 year old SRC plots (planted in 2000) (F1,6 =8.01, p<0.05) and the 2 year old plots (F1,4 =35.98, p<0.01). In year 4 there was also a higher proportion of short-lived perennial species in the SRC plots (F1,11 =30.50, p<0.001). The proportion of stable long-lived perennial species was higher in the SRC in year 1 (F1,11 =5.08, p<0.05), year 2 (F1,9 =5.63, p<0.05) and year 4 (F1,11 =17.25, p<0.001).

The results also indicate a succession towards a more stable plant community within the SRC plots with higher proportions of perennial species and lower proportions of annual species in the established plots in comparison to plots with less than two years growth (Figure 3.12). For the plots planted in 1999 there was a significant decline in the proportion of annual species over the four year study period (F3,14 =4.48, p<0.05).

In addition to changes in the proportions of annual and perennial species within the SRC plots over the four year study period there was also a change in the relative abundance of individual species, as estimated using the domin scale (Table 3.1).

Figure 3.13 shows some examples of the relative abundance (using mean domin scale values) of commonly recorded species, indicating a succession towards a stable plant community. For example, Common Orache an annual species was not recorded in established SRC plots but was occasionally recorded as abundant (25 50% cover) both in recently planted and cutback SRC plots and arable controls. Another annual species, Field-forget-me-not was only recorded as rare (<5% cover)

67 in established SRC plots but was recorded as frequent (10-25% cover) in recently planted SRC. Short-lived perennial species such as Common Nettle Urtica dioica, Broad-leaved Dock and Creeping Buttercup all increased in cover as the SRC plots became established. Common Nettle was regularly recorded as frequent in established SRC plots but was only recorded as rare in young SRC plots and arable controls. Creeping Buttercup was occasionally recorded as dominant (>50% cover) in established plots but was never more than abundant in young SRC. Meadow Grass Poa spp and Yorkshire Fog, examples of long-lived perennial grasses were also recorded at higher domin scale values within established SRC plots in comparison to recently planted and cutback SRC plots or controls.

The results indicate that overall vegetation cover increases in the first year of SRC growth but remains fairly constant after that (Figure 3.14). In the plots planted in 1999 there tended to be an increase in vegetation cover in the first year of growth at the edge of the plot (within 4 metres of the edge) and a significant increase in the plot interior (more than 4 metres from the edge) (F1,7 =6.42, p<0.05). Vegetation cover in the plots planted in 2000 increased significantly in the first year of growth in the plot edge (F1,8 =46.58, p<0.001) although the increase in the plot interior was not significant.

68 1.0

plot type

ro 1.0 "c 2 &8 Q_ I 0.6 O)

plot type

Fig 3.12 Proportion of annual, short-lived perennial and long-lived perennial species within control, young SRC (less than 2yrs growth) and established SRC plots (more than 2yrs growth)

69 5 5

§ 4 4 g c 3 3 I I c 2 2

Field forget-me-not Common Orache

5 5

4- 4

C 3- 3

■o 2- 2 -

0 0

of Common nettle Yorkshire Fog

5 5

Meadow grass Creeping buttercup

5 5

Broad-leaved dock Perennial rye grass

Fig 3.13 Estimated cover of commonly recorded species based on domin scale values within control plots, young SRC plots (<2yr growth) and more established plots. Domin scale values 1=rare 2=occasional 3=frequent 4=abundant 5=dominant (see text)

70 100

SRC growth (yrs)

a) crop edge (up to 4m into crop)

100

CD 80 > 8 c o 60 CD CD 40 CD CD > 20

0 j 0 12 3 SRC growth (yrs)

b) crop interior (>15m into crop)

Fig 3.14 Percentage vegetation cover within SRC at various stages of growth at a) the crop edge and b) the crop interior

71 3.4.7 Weed competition in SRC crop

Summary

Although vegetation height was not measured it is possible to speculate on the effects weed growth could have on SRC yield. In the weediest plots it is possible that yield could be reduced. However, in most circumstances vegetation cover was not high enough to merit further weed control.

In a previous study Sage (1999) found that tall weeds compete with willow grown in SRC during the first year of SRC growth leading to reductions in biomass. Sage (1999) found a relationship between coppice growth in the first year and an index of weediness (vegetation height x % cover).

In this study plots surveyed a few months after planting or cutback had very little vegetation cover. Two sites in year 2 and three sites in year 3 had a mean vegetation cover one year after cutback in excess of 40%. In this study vegetation height was not measured. For these plots a vegetation height of 0.25 metres would give an index of weediness of 10, resulting in a predicted willow growth 94% that of a weed free plot (Sage, 1999). In these circumstances further weed control would not be of economic benefit. However, at one site (Oak Farm) vegetation cover was estimated at 80%. Vegetation cover of this amount may warrant further weed control if vegetation was higher than 0.75 metres as growth of the coppice would only be around 65% of a weed free plot.

The results indicate that in most of the commercial SRC surveyed further control of weeds would not have an economic benefit, and may reduce the crops value as a wildlife habitat.

3.4.8 The influence of surrounding landuse and type of boundary on numbers and types of plant species

Summary

The number of species recorded within quadrats was not determined by the adjacent boundary type or to the surrounding landuse. There is some indication that the proportion of annual species declines more rapidly on plots that are adjacent to arable land than on plots adjacent to grassland.

The boundary adjacent to the start of transects comprised of either hedges or grass strips with fences. The boundary type was not found to be a factor determining the number of species or number of grass species found within the 1 x 10 metre quadrats. In the first year of the study transects adjacent to hedges tended to contain more species than transects adjacent to grass strips, although the difference was not statistically significant. The type of landuse adjacent to the SRC plots was also not a major factor determining the number of species found within quadrats. In the first

72 two years of the study SRC adjacent to grassland had slightly more species than SRC adjacent to arable plots although the difference was not significant (Figure 3.15).

Figure 3.16 compares the proportion of annual, short-lived and perennial species during the last three years of the study on SRC adjacent to both arable land and grassland. Although there was a general decline in the proportion of annual species overall this was only significant for SRC adjacent to arable land for both the 1999 planted plots (F2,8 =11.69, p<0.005) and 2000 planted plots (F2,7 =6.44, p<0.05). There was an increase in long-lived perennial species in 1999 plots adjacent to grassland (F2,9 =14.14, p<0.05).

25 25

S 20 20 % % % 15 15 o o ° 10 10 B B 5 5

0 0 j arable grass arable grass 2000 2001

25 25

20 20 % % 15 15 o o 10 10 B B 5 S 5

0 0 j arable grass arable grass 2002 2003

Fig 3.15 Comparison of the number of species per 1m x 10m quadrat within SRC transects in relation to the landuse (arable or grassland) adjacent to the start of the transect for each year during the study

73 Adjacent landuse ■ arable boundary m grassland boundary

2001 2002 2003 survey year

1.0

0.8

0.6

0.4

0.2

0.0 j 2001 2002 2003 survey year

Fig 3.16 Comparison of the proportion of annual, short-lived perennial and long- lived perennial species within established SRC plots during the last three years of the study in relation to the adjacent landuse.

74 3.5 Discussion

The results of this four year study indicate that commercially planted SRC plots support a richer plant community than the traditional arable plots that they replace. In contrast to traditional arable crops which are harvested annually, SRC plantations are relatively undisturbed enabling a shade tolerant herb and grass community to develop (Sage & Tucker, 1998).

The conditions found in traditional arable plots provided few opportunities for non crop species to establish. Relatively few species were recorded within the arable controls with a greater than 5% cover. The arable controls were more species rich 1 metre from the crop edge than 4 metres, and the majority of species with more than 5% cover were restricted to within 1 metre of the crop edge. Previous studies also show that many non-crop plant species present in arable fields are restricted to the crop edge (Marshall, 1997; Wilson & Aebischer, 1995). In common with the arable plots the edge of young SRC plots had more species than the interior. However, in the established SRC plots the number of species was evenly distributed throughout the crop.

The commonest species recorded within the arable crops were all annuals, with Cleavers, Fat hen, Chickweed and Scentless Mayweed the most frequently recorded. Previous studies also confirm that most non-crop plant species within arable fields are annual species adapted to survive on disturbed land (Marshall & Arnold, 1995). Grasses were also frequently recorded growing within the arable crops, with Annual Meadow Grass Poa annua and Barren Brome Bromus sterilis the most common.

More plant species were found in the arable headlands than within the crop itself. This is to be expected as field margins are usually relatively diverse in comparison to the crop (Marshall & Arnold, 1995). The headlands of the arable controls tended to be less species rich than the SRC headlands. A number of arable headlands were almost entirely dominated by grasses, with Barren Brome in particular being much more abundant in the arable headlands than in the SRC headlands. Regular applications of fertiliser suits species such as Barren Brome, which has been shown to out-compete other grass species at increased nitrogen levels (Tsiouris & Marshall, 1998). Previous studies have shown that species richness declines as a result of agrochemical drift within arable headlands (Kleijn & Snoeijing, 1997). The close proximity of arable headlands to farm operations render them particularly susceptible to disturbance and application of nitrogen fertiliser to non-target areas (Marshall & Moonen, 2002).

The recently planted SRC plots (planted in 2000) had only 11 species recorded. Most of these were annuals reflecting the recent disturbance created when the plots were prepared for planting. Although vegetation cover was not extensive it was much higher than the non-crop cover that was found in the arable controls. The bare ground characteristic of recently planted SRC plots provided less of a barrier to plant colonisation than the densely planted arable crops. In comparison to the recently planted plots, the six plots cutback after one year's initial growth contained significantly more species during that year and vegetation cover was higher. In the

75 last couple of years of the study only one of the sites (Sicklinghall) was eventually harvested. This site also had a high proportion of annuals (60% of the total species) following harvesting.

Recently planted SRC plots would not be expected to be species rich as the existing seed bank on former agricultural land is generally impoverished (Ford, 1996). However, the results indicate that the number of species in commercially planted SRC plots is able to increase in the first year of growth, despite applications of herbicide following cutback. The species that are abundant in the established SRC plots are a mixture of invasive short-lived perennials such as Creeping Thistle, Common Nettle, Creeping Buttercup and Willowherbs EpHobium spp; and long- lived perennials such as Yorkshire Fog, Smooth Meadow Grass and Rough Meadow Grass. Annual species were comparatively rare.

For the first three years of the study more species were found in the SRC headlands than within the SRC crop. However, in year 4 rank grasses in particular Cocksfoot and False Oat Grass were more abundant within the headlands, which meant that the headlands had no more species than the SRC plots. Retaining headlands and open areas within the crop should have a positive impact on plant diversity. The headlands have a particularly valuable role by providing a valuable nectar and pollen supply to beneficial invertebrates. In the shady conditions within the SRC plot many species of plants are unable to flower providing very little nectar source (Reddersen, 2001). The tussocky grasses increasing in abundance in the SRC headlands can support predatory ground beetles which may help to control the number of crop pests (Sage & Tucker, 1998).

The results of this study also document the plant community succession that takes place within commercial SRC plots during the production cycle. The proportion of annual species declined with increased willow growth in the SRC plot. The decline in the proportion of annual species was significant for the plots planted in 1999. The decline in the proportion of annual species was more noticeable in SRC plots adjacent to arable land in comparison to SRC plots adjacent to grassland. The reason for this was probably the higher proportion of annual species that was able to colonise from neighbouring arable land when the SRC was established. In SRC plots planted adjacent to grassland, there tended to be a higher proportion of long- lived perennial grassland species early on in the SRC cycle, which presumably also colonise from the adjoining land. The proportion of stable long-lived perennials is able to increase, although this may depend on their ability to colonise in the first place. For example, there was a significant increase in the proportion of long-lived perennials for those plots planted in 1999 adjacent to grassland.

A stable plant community has already been shown to develop within SRC plots, with annuals and invasive short-lived perennials being replaced by long-lived perennial species (Sage, 1995). In this study there was a tendency for established SRC plots to contain a higher proportion of invasive short-lived perennial species such as Common Nettle, Creeping Thistle, Creeping Buttercup and Willowherbs than SRC with less than one year's growth, although the difference was not enough to be significant. In a previous study carried out on willow SRC planted on peat in Sweden

76 similar invasive species became dominant (Gustafson, 1987). There is only a slight increase in the proportion of long-lived perennial species in established SRC which was not significant. The relatively slow increase in the proportion of stable long- lived perennial species probably reflect that many long-lived perennials, particularly those associated with hedgerows and woodland have slow rates of colonisation (Sage,1995).

Although overall the increase in the proportion of invasive and long-lived stable perennials was not significant there was an increase in the percentage vegetation cover for a number of commonly recorded perennial species (as estimated using the DAFOR scale, see Table 3.1). For example, Common Nettle, a short-lived invasive perennial tolerant of some shade was recorded as no more than rare (less than 5% cover) in SRC plots with less than 2 years willow growth; whereas in established SRC it was regularly recorded as frequent (10-25% cover). Other perennial species tolerant of some shade (e.g. Creeping Buttercup and Willowherbs also showed this trend. Yorkshire Fog, the most commonly recorded long-lived perennial grass was occasionally recorded as abundant (25-50% cover) in young SRC but was only recorded as dominant (more than 50% cover) in older SRC plots.

This shift from annual to perennial species is something that would be expected to occur on land taken out of arable production (Brown & Southwood, 1987; Huusela- Veistola & Vasarainen, 2000). A greater ground cover of slow growing perennials is to be recommended as they have low water and nutrient requirements and reduce invasion by larger weed species thereby reducing the need for herbicide application (Sage, 1995).

The SRC plots used in this study differ from the plots studied previously by Sage (1995) in that they are planted and managed commercially. As well as tending to be larger in size, commercial plots also use fewer and faster growing varieties of willow which allow for a much shorter rotation period between harvesting. Shorter rotations could possibly prevent some stable long-lived perennial species from establishing.

Commercial plots generally have higher inputs of agricultural fertilisers and herbicides than the trial plots previously studied. The amount of herbicide applied is an important factor determining the composition and diversity of plant species (De Snoo, 1997). For example, Common Nettle, a species that was common within the established plots in this study thrives in phosphate-rich habitats (Mabey, 1996), and would be expected to benefit from an application of fertiliser.

Vegetation cover increased significantly during the first year of SRC growth and remained fairly constant after this. The amount of ground vegetation varied between sites, with some sites containing very little ground vegetation. This could reflect the structure of the sites as well as the amount of herbicides applied. Site 6 (Storwood) with the highest mean vegetation cover throughout the study is divided into small plots by a network of hedgerows and surrounds a small area of woodland. The site also had fewer herbicide treatments at establishment than the other plots planted in

77 1999. In contrast, site 4 (Goole Fields) with the lowest mean vegetation cover is small, without hedgerows and surrounded by open arable fields.

In a previous study Sage (1999) found that tall weeds compete with willow grown in SRC during the first year of SRC growth leading to reductions in biomass. Sage (1999) calculated the loss in coppice biomass at various degrees of weediness using an index of weediness (vegetation height x % cover).

Two sites in year 2 and three sites in year 3 had a mean vegetation cover one year after cutback in excess of 40%. Although vegetation height was not measured a height of 0.25 metres in these circumstances would give an index of weediness of 10, resulting in a predicted willow growth 94% that of a weed free plot (Sage, 1999). In these circumstances further weed control would not be of economic benefit. However, at one site (Oak Farm) vegetation cover was estimated at 80%. Vegetation cover of this amount may warrant further weed control if vegetation was higher than 0.75 metres as growth of the coppice would only be around 65% of a weed free plot.

For most of the sites surveyed the amount of weediness was probably not sufficient to warrant further control from an economic point of view. A certain level of weediness can therefore be tolerated and can contribute to the potential of the crop as a habitat for wildlife and game (Sage & Tucker, 1998).

78 3.6 References

Albrecht, H. (2003) Suitability of arable weeds as indicator organisms to evaluate species conservation effects of management in agricultural ecosystems. Agriculture, Ecosystems & Environment. 98 (1-3) : 201-211.

Brown, V.K.B. & Southwood T.R.E. (1987) Secondary Succession: patterns and strategies. In Gray A.J., Crawley M.J. & Edwards P.J. (Eds). Colonisationsuccession and stability. Blackwell Scientific Publications, Oxford.

Clay, D.V. (1996) Weed management in short rotation coppice: current status and future requirements. Reportof the Energy Technology Support Unit, Departmentof Trade and industry. 24pp.

Department of Trade & Industry (1994) New and Renewable Energy: Future Prospects in the UK. Energy Paper Number 62. HMSO, London.

De Snoo, G.R. (1997) Arable flora in sprayed and unsprayed crop edges. Agriculture, Ecosystems, and Environment. 66 (3): 223-230.

Ford, M.A. (1996). The transformation of surplus farmland into semi-natural habitat. Effect of seed supply on the conservation value of Scottish set-aside exemplified by the vegetation at a site near Elgin. Aspects of Applied Biology. 44: 179- 184.

Forsythe, T.G. (1987) Common groundbeetles. Naturalists' Handbook 8 . Richmond Publishing Co. Ltd., Richmond.

Grime, J.P., Hodgson J.G. & Hunt R. (1988) Comparative Plant Ecology. Unwin Hyman, London.

Gustafsson, L. (1987) Plant Conservation aspects of energy forestry - a new type of landuse in Sweden. Forest Ecology and Management. 21 (1-2):141-161.

Huusela-Veistola, E. & Vasarainen, A. (2000) Plant succession in perennial grass strips and effects on the diversity of leafhoppers (Homoptera, Auchenorrhyncha). Agriculture, Ecosystems, and Environment 80 (1-2): Issue 1-2. 101-112.

Kleijn, D. & Snoeijing, G.I.J. (1997) Field boundary vegetation and the effects of agrochemical drift: Botanical change caused by low levels of fertiliser and herbicide. Journal of Applied Ecology. 34 (6): 1413-1425.

Marshall, E.J.P. & Arnold, G.M. (1995) Factors affecting field weed and field margin flora on a farm in Essex, UK. Landscape & Urban Planning. 31: 205-216.

Marshall, E.J.P. (1997) Distribution patterns of plants associated with arable field edges. Journal of Applied Ecology. 26 (1): 247-257.

79 Marshall, E.J.P. & Moonen, A.C. (2002) Field margins in northern Europe: their functions and interactions with agriculture. Agriculture, Ecosystems, and Environment. 89 (1-2): 5-12.

Mabey, R (1996) Flora Britannica. Sinclair-Stevenson, London.

Redderson, J. (2001) SRC-Willow (Salix viminaii$ as a resource for flower-visiting insects. Biomass and Bioenergy. 20 (3):171-179.

Sage, R.B., Robertson P.A. & Poulson J.G. (1994) Enhancing the conservation value of short rotation biomass coppice- Phase 1 the identification of wildlife conservation potential. Report of the Energy Technology Support Unit, Department of Trade and Industry.

Sage, R.B. (1995) Factors affecting wild plant communities occupying short rotation coppice crops on farmland in the UK and Eire. Brighton Crop Protection Conference- Weeds-1995 7D-5: 985-990.

Sage, R.B. & Tucker K. (1998) Integrating crop management of SRC plantations to maximise crop value, wildlife benefits and other added value opportunities. Report of the Energy Technology Support Unit, Department of Trade and Industry.

Sage, R.B. (1999) Weed competition in willow coppice crops: the cause and extent of yield losses. Weed Research 39: 399-411.

Wilson, P.J. (1992) Britains Arable Weeds. British Wildlife 3: 149-161.

Wilson, P.J. & Aebischer, N.J. (1995) The distribution of dicotyledonous arable weeds in relation to distance from field edge. Journal of AppliedEcology. 32: 295 310.

80 3.7 Appendix

Table 3.2 Complete list of plant species recorded within SRC and Control sites and headlands throughout the four-year study. Shows the mean percentage of sites in which each individual species was recorded over the four years. Class 1= Annual species Class 2= Short-lived perennial species Class 3= Long lived perennial species

SPECIES Class SRC Control mean Mean % sites % sites

Aegopodium podagraria Ground elder 2 0 2 Aethusa cynapium Fool's parsley 1 2.5 2.5 Agrostis canina Velvet bent 3 7.5 5 Agrostis capillaries Common bent 3 15.7 4.5 Agrostis gigantean Black bent 3 4.5 18.7 AHiaria petiolata Garlic mustard 2 2 4 A/nus glutinosa Alder 3 2 0 Alopecurus geniculatus Marsh foxtail 2 19.3 7 Alopecurus myosuroides Black grass 1 10 4 Alopecurus pratensis Meadow Foxtail 3 51.7 40.5 Anagallis arvensis Scarlet pimpernel 1 2 2 Anthoxanthum odoratum Sweet vernal grass 3 4.5 0 Anthriscus sy/vestris Cow parsley 2 12.8 30 Arcticum lappa Greater Burdock 2 2 4 Arrhenatherum elatius False Oat Grass 3 43.7 52 Artemisia vulgaris Mugwort 2 11 11 Atripiex patuia Common orache 1 15.3 15.5 Avenafatua Wild oat 1 6.2 6.8 Avena strigosa Bristle oat 1 4.5 0 Beilis perennis Daisy 3 17 2 Betuia spp Birch 3 2 0 Boragoofficinalis Borage 1 0 2 Brassica napus Oil seed rape 1 4.3 15.5 Bromus commutatus Meadow brome 3 27.5 41.7 Bromus diandrus Great brome 1 2 4 Bromus mollis Soft brome 3 10 5 Bromus ramosus Hairy brome 3 6.2 0 Bromus steri/is Barren brome 1 30.8 67.5 Caiystegia sepium Hedge bindweed 2 8.3 8.3 Capseiia bursa-pastoris Shepherd's purse 1 6.2 24

81 Carex spp Sedge 3 10.3 0 Centaurium erythraea Common centaury 1 4.3 0 Cerastium arvense Field mouse ear 1 2 7 Cerastium fontanum Common mouse ear 1 36.8 13 Cerastium glomeratum Clustered mouse-ear 1 2.5 0 Chamaenerion angustifolium Rosebay Willowherb 2 0 2 Chenopodium album Fat hen 1 28.7 45.5 Chenopodium ficifolium Fig-leaved goose-foot 1 4.5 5 Chenopodium muraie Nettle-leaved goose foot 1 2 4.5 Chenopodium vuivaria Stinking goose-foot 1 0 4.5 Cirsium arvense Creeping thistle 1 77.2 64 Cirsium pa lustre Marsh thistle 2 4.5 4.5 Cirsium vuigare Spear thistle 2 62.5 32 Convoiovuius arvensis Field bindweed 1 4.5 14.5 Coronopus squamatus Swinecress 1 2 9.2 Crataegus monogyna Hawthorn 3 15.5 6.5 Crepis capillaries Smooth hawk's-beard 2 9.5 2 Cynosurus cristatus Crested dog's-tail 3 0 4.5 Dactyiis giomerata Cocksfoot 3 58.5 47.8 Deschampsia cespitosa Tufted hair-grass 3 19.8 2 Digitalis purpurea Foxglove 2 2.5 0 D/psacus fuiionum Teasel 2 2 0 Eiymus repens Couch grass 1 37.5 37.2 Epiiobium ciiiatum American willowherb 2 25.8 5 Epiiobium hirsutum Great willowherb 2 46.8 20.2 Epiiobium parvifiorum Hoary willowherb 2 20.8 0 Epiiobium spp Willowherb 2 49.5 9 Equisetum spp Horsetail 2 41.5 41.2 Euphorbia heiioscopia Sun spurge 1 0 2 Fagus syivatica Beech 3 0 0 Festuca pratensis Meadow fescue 3 17.5 4.5 Festucarubra Creeping fescue grass 3 29.2 19.5 Fumaria officinalis Common fumitory 1 0 4.5 Galium aparine Cleavers 1 58.7 82.7 Galium moiiugo Hedge bedstraw 2 2.5 5 Geranium coiumbinum Long-stalked cranesbill 1 12.5 20.5 Geranium dissectum Cut-leaved cranesbill 1 31.2 22 Geranium moiie Soft cranesbill 1 15.5 8.8 Geum urbanum Wood avens 2 4.3 0 Giechoma hederacea Ground ivy 2 0 10.8 Giyceria fiuitans Floating sweet-grass 3 2.5 0 Glycine max Soya 1 0 2 Hedera helix Ivy 3 0 6 Heracieum sphondyiium Hogweed 2 37 66.7 Hieracium spp Hawkweed 2 4 0

82 Holcus lanatus Yorkshire fog 3 84.2 56.7 Holcus mollis Creeping soft grass 3 33 23 Hordeumdistichon Two-rowed barley 1 4 17.3 Hypochaeris radicata Cat's ear 3 21.7 12.8 Illex aquifolium Holly 3 0 2 Juncus effuses Soft rush 3 6.2 0 Juncus conglomerates Common rush 3 22.5 0 Lamium album White dead nettle 2 5 14.5 Lamium purpureum Red dead nettle 2 4 10.5 Lathyrus pratensis Meadow vetchling 3 0 6 Linum usitatissimum Linseed 1 2 4.5 Lolium multiflorum Italian rye grass 3 24.5 8.7 Lolium perenne Perennial rye-grass 3 62.5 51.7 Lotus corniculatus Birdsfoot trefoil 3 2 4.3 Malva pusiHa Small mallow 1 2.5 0 Matricaria matricarioides Pineapple weed 1 19.8 13 Matricaria recutita Scented mayweed 1 7.5 0 Medicago lupulina Black medick 1 6.2 4 Mysostis arvensis Field forget-me-not 1 21.2 13 Papaver rhoeas Common poppy 1 8.7 15 Polygonum hydropiper Water pepper 1 2.5 4.5 Polygonum persicaria Redshank 1 14.5 16.5 Petasites hybridus Butterbur 3 0 2 Phaiaris arundinacea Reed grass 3 2 4.3 Phieum pratense Timothy 3 22.5 8.5 Phragmites australis Common reed 3 6.5 12.8 Piantago lanceolata Ribwort plantain 3 8.3 6.2 Piantago major Greater plantain 2 29 10.3 Piantago media Hoary plantain 2 5 2.5 Poa annua Annual meadow grass 1 41.7 68.5 Poa pratensis Smooth meadow grass 3 46.2 25 Poa triviaiis Rough meadow grass 3 60.5 54.2 Polygonum avicuiare Knotgrass 1 14.8 28 Polygonum convolvulus Black bindweed 1 0 4 Populus spp Poplar 3 17 9 Prunella vulgaris Selfheal 3 12.2 0 Prunus spinosa Blackthorn 3 0 2 Quercus (seedling) Oak 3 19.5 10.8 Ranunculus acris Meadow Buttercup 3 13.3 0 Ranunculus repens Creeping buttercup 2 83.3 37.2 Raphanus raphanistrum Wild radish 1 0 9 Rosa canina Dog rose 3 6.2 4 Rubus fruticosis Bramble 3 41.8 32 Rumex acetosa Common sorrel 3 9.5 2 Rumex acetoseiia Sheep's sorrel 3 12.5 10.5

83 Rumex conglomerates Clustered dock 2 22 16.5 Rumex crispus Curled dock 2 19.8 15 Rumex longifolius Long-leaved dock 2 2.5 0 Rumex obtusifo/is Broad-leaved dock 2 61.2 44 Sambucus nigra Elder 3 2.5 0 Senecio jacobaea Ragwort 2 19.8 7 Senecio vulgaris Groundsel 2 35.3 26.7 Silene alba White campion 2 2 4.5 Silene noctiflora Night-flowering catchfly 1 0 2.5 Silene vulgaris Bladder campion 2 0 2 Sinapis arvensis Charlock 1 9 0 Sisymbrium officinale Hedge mustard 1 4.3 2 Sonchus arvensis Perennial sowthistle 1 0 11.3 Sonchus asper Prickly sowthistle 1 50.2 15.3 Sonchus oieraceus Smooth sowthistle 1 8.5 6.5 Sperguia arvensis Corn spurrey 1 0 4.3 Stachys syivatica Hedge woundwort 3 8.5 13 Stellaria media Common chickweed 1 14.8 30 Tanacetum vuigare Tansy 2 0 4.3 Taraxacum officinale Dandelion 1 64 35.5 Taraxacum spectabilia Red veined dandelion 1 0 2.5 Toriiisjaponica Upright hedge parsley 1 7 9.2 Trifolium dubium Lesser yellow trefoil 1 17.5 2 Trifolium pratense Red clover 3 10.3 0 Trifolium repens White clover 3 52.2 17.5 Tripieurospermuminodorurr i Scentless mayweed 1 56.7 27.7 Trisetum f/avescens Golden oat grass 3 5 0 Triticum aestivum Bread wheat 1 16.8 46.8 Tussi/agofarfara Coltsfoot 2 6.2 0 Urtica dioica Common nettle 2 41 73.7 Urtica urens Annual nettle 1 6.8 4.5 Veronica arvensis Wall speedwell 1 0 2.5 Veronica beccabunga Brooklime 3 2 0 Veronica hederifoiia Ivy-leaved speedwell 1 0 9.5 Veronica persica Field speedwell 1 24.3 30.2 Veronicaserpyllifolia Thyme-leaved speedwell 3 6.5 2 Vicia cracca Tufted vetch 2 8.5 6 Vicia hirsute Hairy tare 1 0 2.5 Vicia sativa Common vetch 3 2 0 Vicia sepium Bush vetch 2 6.2 10.7 Viola arvensis Field pansy 1 6.2 12.8

84 4. BIRDS IN WINTER

4.1 Summary

Winter birds were monitored within the 12 SRC plots and 12 arable control plots for three consecutive winters. Each plot was visited on four separate occasions during the winter. The total number of species recorded during this period was higher in the SRC plots than it was in the arable controls. A similar result was obtained during the spring visits to the same sites (Section 2.0), indicating that the habitat created in the planting of commercial SRC plots suits a wider range of species throughout the year than would normally be found in traditional arable crops. In common with the spring bird data collected more species of birds were recorded per visit in the SRC than the arable controls. Overall the number of individual birds wintering in established SRC plots was no different to the numbers wintering in arable fields. However, the main reason for this is the occasionally large flocks of Gulls, Woodpigeons and Finches that were recorded on the arable fields. The arable controls were more likely to be devoid of birds than the SRC plots. On average more individual birds were recorded in young SRC plots than arable plots.

The young SRC were particularly important for Buntings, with relatively large flocks of Yellowhammer and Reed Bunting noted. Both Reed Buntings and Yellowhammers are red-listed species of conservation concern (see Table 4.2). Many species, in particular Finches, Thrushes and Game birds showed a preference for younger SRC; and for Buntings there was a significant decline with the growth of the willow crop. In contrast the results from the spring data show many species of birds to increase with SRC growth. One particular group of birds, Tits increased in number with the growth of the willow crop during the winter as well as in spring (Section 2.0). Several species associated with open habitat such as Grey Partridge (also a red-listed species) and Lapwings were not recorded in established SRC.

The spring surveys showed both Skylarks and Waders (predominantly Lapwings) to prefer recently planted and cutback SRC to arable fields (Section 2.0). Unfortunately, by the start of the winter monitoring in November 2001 the youngest SRC had one year's growth. It is not possible therefore to determine if these species make use of recently established SRC plots in the winter. Both Skylarks and Lapwings were more frequent in the arable controls than the SRC. Both species are of conservation concern (Gregory et a!., 2002) (see Table 2.3, at the end of the section). Prior to the final survey in February 2004 a number of the SRC were harvested, and although no Skylarks or Lapwings were recorded during this final survey Meadow Pipit (another species characteristic of open habitat, and an amber listed species of conservation concern (Gregory et al, 2002) was recorded. Both Snipe and Woodcock were regularly flushed from the SRC plots but rarely recorded in the arable plots.

85 4.2 Introduction

The value of modern farmland to birds during the winter is currently of particular interest to conservation groups. Many bird species associated with farmland habitats have declined in recent years (Baillie etai., 2001). One factor contributing to this decline has been the loss of weed rich winter stubbles that provide a key foraging habitat for many species (Moorcroft et ai., 2002). Many species of arable weed set seed in the autumn and provide a valuable input of food during the winter when other resources become depleted (Wilson, 1992). Several species, such as Reed Bunting, Tree Sparrow and Grey Partridge have been found to be more abundant where weed cover is higher (Henderson et ai., in press).

Any habitat that provides shelter and a source of food during the winter for birds may prove of vital importance to the status of that individual species within the countryside. For many species such as Song Thrush and Reed Bunting mortality outside the breeding season may be a major factor contributing to their decline (Thomson et ai., 1997; Siriwardena et ai., 1998).

Short Rotation Willow Coppice (SRC) is potentially an attractive habitat for wintering birds. The perennial nature of SRC means that some weed growth can occur without necessarily compromising the development of the willow crop (Sage, 1999). SRC varies in structure over the period of the production cycle, and once established provides a woodland type habitat that may attract a different bird community from that found in traditional annual arable crops.

Previous monitoring of SRC during winter has already given some indication of the potential value of the crop to wintering birds (Sage & Tucker, 1998). In this previous study a total of twenty-nine species of birds, several of which are of particular conservation concern were recorded from SRC plots during one winter (Sage & Tucker, 1998). Despite the fact that SRC are normally dry habitats they have been found to provide a roosting area for wintering Snipe that fly out at night to feed on soft pastures (Sage & Tucker, 1998).

This study differs from the previous study in a number of ways. The SRC plots used in this study are all commercially planted and managed plots and therefore tend to be larger and have a higher input of fertilisers and herbicides than the previously studied plots. Sage & Tucker (1998) found that bird density decreased with increasing size of the SRC plantation. Higher levels of fertiliser may result in less weed cover and consequently may not provide as abundant a supply of seeds. This study is designed to be more comprehensive with plots visited over a period of three consecutive winters at four times each winter. Repeated visits to the same plots provides a better understanding of the use of SRC by wintering birds as many species are especially mobile in winter and migrate in response to cold weather conditions (Lack, 1986).

The use of arable control plots allows comparisons to be made between the SRC plots and arable crops that it replaces.

86 4.3 Methods

Each of the 12 SRC and control plots was monitored on four separate occasions during three consecutive winters (starting in the winter of 2001-2002). The monitoring was spread out over the winter period with surveys conducted in November, December, January and February.

Each site was surveyed by walking the headlands and rides as well as through the willow crop for a period of one hour, recording all birds seen or heard. The transect through the centre of the SRC and arable plots was positioned at the centre of the plot, along its longest axis. Arable plots were surveyed in the same way by walking the parameters and a transect through the crop and were surveyed on the same day as their respective SRC plots.

87 4.4 Results

4.4.1 Comparison between the total number of birds and number of species present in SRC and arable controls during winter

Summary

During the period of the study more species were recorded in the SRC than the arable controls. The average total number of birds over four visits throughout the winter periods was higher in the younger SRC than the arable controls. Despite the fact that the size of bird flocks on the arable controls often relatively higher, with occasional large flocks of Woodpigeons, Gulls and Finches. The number of species recorded varied considerably between individual SRC plots. Younger SRC was found to be more species rich than either arable fields or established SRC. The established SRC were also more species rich than the arable controls.

A total of forty-three species were recorded as wintering in the SRC plots between November and February during the period of the study. In comparison, thirty-nine species were recorded wintering in the arable controls during the same period (Table 4.1)

Young SRC plots (i.e. plots which had been recently planted, harvested or with less than one years growth) supported more individual birds during the period of the study than the controls (F1,47 =6.16, p<0.05) (Figure 4.1). The number of birds within the established SRC was similar to that found in the controls. However, this was largely due to the presence of occasional large flocks of Woodpigeons and Gulls within the arable fields. Woodpigeons were the most frequently recorded species within the arable control plots, with flocks of more than one hundred birds recorded on three separate occasions. There was a maximum count of 152 Herring gulls present in the ploughed field at Far Shires in February 2004. The arable fields also occasionally contained finch flocks, including a maximum count of 200 Goldfinches in the mixed cereal crop at West Farm in February 2002. Despite this the arable controls were frequently devoid of birds, with no birds recorded on 25% of visits. In contrast, only 6% of visits to SRC plots failed to produce any birds.

The mean number of species recorded in the SRC plots was 5.49±0.32 per visit, compared to 2.15±0.25 per visit in the arable controls. The mean number of species per visit over the winter was higher in the SRC plots than the arable controls for each year of the study; in year 1 (F1,10 =16.19, p<0.05) year 2 (F1,11 =48.84, p<0.001) and year 3 (F1,11 =47.26, p<0.001). Overall, more species were recorded in young SRC per visit than either the arable controls (F1,47 =49.13, p<0.001) or the established SRC plots (F1,27 =5.87, p<0.05) (Figure 4.1).

88 200 E 150 o s—

a) b) c) plot type

30 O 20 s—

Fig 4.1 Total number of individual birds and total number of species recorded during winter visits to SRC plots and arable controls during the three year survey period. a)=arable control plots b) recently established or harvested SRC plots c) SRC with more than one year of willow growth

89 $ 30 o O 20

Fig 4.2 Total number of bird species recorded wintering at each of the twelve SRC study sites during the 3-year study period

4.4.2 Comparison between different groups of species present in SRC and arable controls during winter

Summary

Many species of passerines were more abundant in the SRC than the arable controls; including Finches, Buntings, Thrushes, Tits, Robins, Wrens and Dunnocks. However, Skylarks were more frequently recorded in arable plots. Snipe and Woodcock were frequently flushed from the SRC plots but were rarely recorded from the arable plots. Lapwings were occasionally recorded from the arable fields, but there was only one record of a single bird in the SRC plots during the period of the study. Game birds tended to be more abundant in the SRC, in particular Red legged Partridge and Pheasant. Grey Partridges were recorded in similar amounts from both arable plots and young SRC, but were absent from established SRC plots.

Many species were more frequently recorded in the SRC than the controls. Figure 4.3 compares the mean number of Finches, Buntings and Thrushes recorded in the SRC and control plots. There were significantly more finches in the SRC in year 2 (Fi,ii =17.23, p<0.01) and year 3 (F1,11 =8.87, p<0.05).

90 Fig

4.3 mean number of birds mean number of birds mean number of birds

10 10 10 Mean 2 4 6 4 6 4 6 0 8 8 8

visits

number SRC SRC SRC

to thrushes buntings finches

SRC control control control

plots

Finches,

and

arable Buntings 91

controls

and

Thrushes

throughout

recorded

the

study

during

winter The most abundant bird both in young and established SRC was the Chaffinch, which frequently occurred in small flocks, numbering approximately 40 individuals on one occasion.

The number of Buntings was also significantly higher in the SRC than the controls both in year 1 (F1,10 =15.45, p<0.005) and year 2 (F1,11 =8.09, p<0.001). In the first year of the study Yellowhammers and Reed Buntings were especially frequent in SRC plots with one year of willow growth. A maximum count of 59 Yellowhammers and 35 Reed Buntings were recorded at South Cave during this year.

Thrushes were also frequently recorded as wintering within SRC plots. The SRC plots had significantly more thrushes in year 1 (F1,10 =21.31, p=0.001), year 2 (F1,11 =6.91, p<0.05) and year 3 (F1,11 =10.89, p<0.01). Blackbirds were regularly recorded and were found in all 12 sites, although the maximum count at any one site on a particular day was seven. Song Thrushes were also occasionally recorded. Fieldfares and Redwings were recorded from ten of the SRC plots monitored, and were present during every winter throughout the study. The numbers of strictly winter thrushes (i.e. Fieldfares and Redwings) tended to also be higher in the SRC, although for these two species the difference between SRC and arable controls was not enough to be significant.

The mean number of Tits; Accipters (i.e. Robins, Wrens and Dunnocks) and Pipits recorded in the SRC tended to be higher than in the control plots (Figure 4.4). Tits were a feature of more established plots, with Long-tailed Tits recorded in seven out of the twelve plots monitored between November 2003 and February 2004, with a maximum flock size of nine birds on one occasion. The number of Tits was higher in the SRC in year 2 (F1,11 =11.20, p<0.01) and year 3 (F1,11 =23.74, p<0.001). Accipter type species (Robins, Wrens and Dunnocks) were also higher in the SRC during year 1 (F1,10 =8.60, p<0.05), year 2 (F1,11 =21.27, p=0.001) and year 3 (F1,11 =16.94, p<0.01). Very few Accipter species or Tits were recorded in the arable controls, and they were associated with surrounding hedgerows. Meadow Pipits tended to be more frequent in the SRC plots, although the difference between sRc and control plots in terms of numbers of this species was not significant.

92 recorded Fig

4.4

mean number of birds mean number of birds mean number of birds Mean

2 4 2 4 2 4 3 3 5 0 3 5 1 1 during

- - - - robins,wrens

number

SRC SRC SRC winter

tits

control control control

of dunnocks visits

Tits;

Accipters

SRC

plots

(Dunnocks, 93

and

arable

Wrens

controls

and

throughout

Robins),

and

the

Pipits

study The mean number of Waders, Game Birds and Skylarks recorded in the SRC and control plots is shown in Figure 4.5.

Overall the number of Waders wintering within the SRC plots was similar to the number recorded in the arable controls. However, there was a difference in preference between individual species of wader. Lapwing (a species associated with open habitats) was more abundant over the three year period in the arable controls (F1,57 =9.07, p<0.01); whereas Snipe were more abundant in the SRC (F1,57 =4.53, p<0.05).

Lapwings were recorded from arable control plots during each year of the study, with flocks ranging from 5 to 32 individuals. In contrast, there was only one Lapwing recorded from a SRC plot during the study. There were two occasions when Golden Plover was found within the arable control plots; both sightings involved a small flock of 4 individuals during a particularly cold spell in year 2. Redshank was recorded on two occasions within the SRC both at the same site in year 1 of the study, and involving a maximum count of 3 individuals. There was a single record of a Redshank from the arable controls also during the same winter. Both Snipe and Woodcock were regularly flushed from the SRC plots, and the results gathered on these species within SRC are discussed further in Section 4.4.4.

Skylarks were recorded from more than a quarter of visits to the arable plots, with a maximum count of 32 birds at Charity Farm in January 2003. Over the three consecutive winters skylarks were more abundant in the arable controls than the SRC plots (F1,57 =8.87, p<0.01), this difference was most apparent in year 1 (F1,10 =10.45, p<0.01).

The SRC plots supported higher numbers of game birds than the other arable crops. The number of game birds in the SRC plots was higher than that of the arable controls during year 1 (F1,10 =5.48, p<0.05), year 2 (F1,11 =10.67, p<0.01), and year 3 (F-,,11 =25.76, p<0.001). Grey Partridges were recorded on three separate occasions in SRC plots with just under a year's growth, and included a flock of 16 birds present on Duffield Lodge in the first year of the study. Grey Partridges were also recorded in four of the arable control plots, with a maximum count of 10 birds at one of the South Cave sites in the second year of the study. Red-legged Partridges were recorded in nine of the twelve SRC plots. Pheasants were frequently recorded in the SRC plots, but only occasionally found in the other arable crops. During the three- year study period each of the twelve sites contained pheasants at some point.

94 Fig

4.5

mean number of birds mean number of birds mean number of birds Mean 2 4 2 4 2 4 0 3 5 3 5 3 5 1 visits

number SRC SRC SRC

game to skylarks waders

SRC

birds of control control control

plots Waders,

and j

Game arable

95 birds

controls

and

throughout Skylarks

recorded

the

study

during

winter 4.4.3 Use of different age classes of SRC by wintering birds

Summary

Many species including Finches, Winter Thrushes (Fieldfares and Redwings) and Game birds tended to be more abundant in younger SRC although the slight decline in numbers of these species with the age of the plot was not significant. Buntings showed a significant decline with the increased age of the willow coppice. The total number of species associated with open habitat (i.e. Waders, Wagtails, Pipits and Skylarks) also showed a significant decline with the age of the SRC. The total number of Skylarks also declined with increased age of the willow crop. Skylarks were absent from SRC with more than 2 years growth. Tits increased in abundance with growth of the SRC, with Long-tailed Tits and Blue Tits frequently recorded in SRC with 4 years of growth.

Of the forty-three species of birds found within the SRC only 25 species were recorded in SRC with more than one years willow growth. Most of the species missing from established plots were those species associated with more open habitat such as Skylark, Grey Partridge, Lapwing and Pied Wagtail. Both Barn Owl and Kestrel were recorded as hunting over recently established SRC plots.

The SRC tended to become less attractive to several species of wintering birds with each successive year of willow growth. Finches and Winter Thrushes (Fieldfare and Redwing) tended to prefer SRC in the early stages of establishment, although there was no significant decline in numbers with each years willow growth. However, for Buntings there was a significant decline in numbers with each year of growth (F3,20 =5.27, p<0.01) (Figure 4.6) .

Numbers of Game birds also tended to decline with the age of the coppice, although this was not a significant decline. The maximum count of Red-legged Partridges was a total of 25 birds from the site at Newsholme in December 2001, when the willow had only one year's growth. In the following winter Red-legged Partridges were recorded in all of the six plots with only 2 year's growth, but not in the sites with 3 years growth. In the final year of the study, Red-legged Partridges were only recorded from three sites.

The total number of species associated with open habitat (i.e. Waders, Wagtails, Pipits and Skylarks) declined significantly with each year of SRC growth (F3,20 =7.56, p=0.001). Of these Skylarks were significantly more abundant in one year old SRC than any other age class (F3,20 =3.09, p=0.05), surprisingly no skylarks were recorded in the few SRC that were harvested (year 0 in Figure 4.7) in the final year of the project. There were also no Skylarks in plots with more than two years growth. The only group of birds that showed a positive increase with SRC growth were Tits (F3,20 =4.14, p<0.05) with Blue Tits and Long-tailed Tits especially frequent in 4 year old coppice (Figure 4.7).

96 (Fieldfares Fig

4.6 Total number of winter thrushes Total number of buntings Total number of finches 20 40 20 40 20 40 30 50 30 30 50 10 10 10

0 0 0 Comparison

------&

Redwings) 0 0 0

SRC SRC SRC 1 1 1

growth growth growth 2 2 2

(years) (years) (years) relation

recorded 3 3 3 total

4 4 4

numbers

to j

in growth

SRC

97 during

of Finches,

the

winter willow

Buntings

visits crop

and over

Winter

3-year

Thrushes

period

in Fig open

4.7

H _Q "2 H _Q _Q o « E 0 O Q_ 0 Q_ O C 3

habitat

Comparison Total number of open species Total number of tits Total number of game birds 20 20 20 10 15 10 15 10 15 0 5 0 5 0 5 visits __ ^

0 0 0 (Waders, SRC SRC SRC

over

growth growth growth 1 12 12

of a __

3-year 2 total L

____

(years) (years) (years) Pipits, 3 3 3

1 ____ numbers

period

Wagtails 1

relation

Game and 98

Skylarks)

birds, to

growth

Tits

recorded

and of

the

species

in willow

SRC

associated

during crop

winter

with

4.4.4 Use of SRC plots by wintering Snipe and Woodcock

Summary

Both Snipe and Woodcock were regularly flushed from the SRC plots during every winter of the study. Numbers of Snipe varied between different winters and different plots, suggesting that they are more abundant in some years, and also that some SRC plots were more suitable for the species than other sRc plots. Woodcock were recorded from both established SRC plots and those SRC plots that were harvested in the final year. Both species were only rarely recorded within the arable controls.

Snipe and Woodcock were frequently flushed from the SRC plots during the winter. Snipe was the most frequently recorded wader within the SRC and was recorded from nine out of the twelve SRC plots during the three-year study period. Four of the sites contained Snipe during each winter of the study.

Numbers of Snipe recorded varied considerably between survey years. The species was particularly abundant in the second winter of the study (2002-3). In this year a total of 87 birds were recorded using SRC between November and December.

Snipe tended to be more frequent in SRC with one years growth, although there was no significant difference between the age classes of SRC (Figure 4.8). The site with the highest numbers of Snipe present (accounting for almost half the birds recorded during year 2) was the site at Foggathorpe (site 12). This particular site was replanted the previous winter following crop failure. Numbers of Snipe in year 3 (winter 2003-4) were low. The maximum number of Snipe to be recorded that year was 5 birds in February 2004 at Sicklinghall, (a site also with one year's growth following cutback the previous winter).

Woodcock were regularly recorded from the SRC plots, and were found within SRC of various age classes during each of the three consecutive winters (Figure 4.8). Sightings normally involved single birds, although a maximum of three were recorded from one plot. In the final year, Woodcock were flushed from two of the four plots that had recently been cutback, suggesting that cutback plots are also a good habitat for this species. There was only one record of a single Woodcock from the arable plots during the period of the study.

99 20

0 0 12 3 SRC growth (years)

SRC growth (years)

Fig 4.8 Comparison of total numbers of Snipe and Woodcock recorded in SRC during winter visits over a 3-year period in relation to growth of the willow crop

100 4.5 Discussion

The aim of this study on wintering birds within SRC was to determine the extent to which farmland birds use this crop in winter compared to traditional annual arable crops. This is especially important as many bird species are declining as a result of changing agricultural practices (Baillie et al, 2001). One previous study has shown that SRC provides a good wintering habitat for a number of bird species, including species such as Song Thrush and Reed Bunting, which are of conservation concern (Sage & Tucker, 1998). A number of the species recorded previously in SRC such as Long-tailed Tits are more typical of woodland and hedgerows and reflect the woodland type structure found in established SRC (Sage & Tucker, 1998).

This study differs from the previous one in a number of ways. Unlike the previous study it was carried out over three consecutive winters. This takes into account the fact that there is a lot of climatic variability between different winters, influencing the bird species and numbers of birds present within the SRC and arable crops. Many species of birds wintering in the UK will migrate towards the south and west in response to cold weather conditions and will also move short distances in response to seasonal changes in food availability (Lack, 1986). By monitoring wintering birds over a three-year period it was hoped that a more comprehensive understanding of the value of SRC to wintering birds could be achieved.

Also in contrast to the previous study the SRC plots used in this study are all commercially planted and managed. They tend to be larger in size and be subjected to higher inputs of fertilisers and herbicides than the previous plots. Any increase in herbicide or fertiliser is likely to reduce the amount of weed cover, which may be detrimental to many species of birds that would potentially use commercial SRC plots. Many species are more abundant where weed cover is higher (Henderson et al., in press). The size of the plot may also be a factor determining the number of birds present within that plot. Sage & Tucker (1998) found that larger plots contained fewer birds, and suggest this may be because smaller plots have a higher edge to area ratio. It has been previously documented that birds are more numerous at the interface between two habitat types (Weins, 1989)

The use of adjacent arable control plots also enables SRC plots to be compared to the arable fields that they are likely to replace. This is important, as many farmland birds presently declining such as Lapwings and Skylarks are associated with open habitats.

Over the three-year period more species of birds were recorded in the SRC than the arable control fields. On average there were also more species recorded per visit in the SRC plots. The number of individual birds per visit in established SRC did not differ from the number recorded in the arable controls. However, this was due to several arable sites containing large flocks of Woodpigeons and Gulls on a number of visits. Flocks of Gulls are to be expected on arable land that is ploughed in the winter, as there is a good supply of earthworms (Lack, 1986). The maximum count of 152 Herring Gulls on the arable plot at Far Shires probably reflects the fact that this

101 site is fairly close to a landfill site. The other species regularly recorded in large flocks on the arable sites was the Woodpigeon, which is considered an avian pest feeding on winter cereal sowings (Lack, 1986).

The SRC sites used during this study varied in the number of species that they contained. The site at Goole Fields was the site with the fewest species recorded on average. This particular site is one of the smaller sites to be used and was fairly uniform in structure with no open areas or rides, it was also almost entirely surrounded by large blocks of arable fields with few hedgerows to act as wildlife corridors. Berg (2002) found adjacent habitat to be the major factor, as well as height of the willow coppice, in determining the number of breeding species found within SRC plots. It seems reasonable to speculate that surrounding habitat and structure within the plot is also a factor determining bird diversity in the winter. A network of hedgerows and small woodland within the SRC plot at Storwood probably accounts for the relatively high diversity of birds recorded here, including Siskin, which was only recorded at this site.

The young SRC (with less than one years growth or recently harvested) contained, on average, more species per visit than either the arable controls or the established SRC. Plots with one year of growth appeared to be attractive to relatively large flocks of Yellowhammers and Reed Buntings. These are species that form winter feeding flocks within agricultural habitats, and feed mainly on the seeds of grasses on the ground (Lack, 1986). The canopy of the SRC at this stage in its development is not yet fully formed providing plenty of relatively open habitats for these species to feed. There is also a greater variety of vegetation growing within the willow plantation, which is not found within densely planted traditional arable crops.

The number of Game birds was higher in the SRC that the arable controls; Grey Partridge was recorded both in young SRC plots and arable plots, whereas Red legged Partridges were more abundant in the SRC. This is probably to be expected as Red-legged Partridges favour less open habitat than the grey partridges during the winter, and probably benefit more from the cover that the SRC provides (Lack, 1986). Thrushes were more common in the SRC that the controls, with Blackbird being abundant within the SRC. Song Thrush was occasionally recorded within the SRC; this is a species that is red listed as being of high conservation concern (Gregory et al., 2002). Red listed species are defined as; "...those whose population or range is rapidly declining, recently or historically, and those of global conservation concern". (Gregory et al., 2002). Redwings and Fieldfares were recorded from both arable and SRC plots. Redwings were slightly more common than Fieldfares in the SRC perhaps due to their preference for foraging on the ground within woodland (Lack, 1986).

Many of the species found within the SRC tended to show a decline with the increased growth of the willow crop, this decline was statistically significant both for Buntings and species preferring open habitats (i.e. Waders, Wagtails, Pipits and Skylarks). For these species the reduction is probably due to the decrease in the extent of open habitat as the willow crop establishes. However, there also remains the possibility that many species of birds may be more difficult to detect in less open

102 habitats, and therefore be under recorded (Bibby et al., 1992). One group of birds that did increase as the SRC became more established were Tits, with both Blue Tits and Long-tailed Tits frequently recorded in small flocks.

Passerine species were generally rare in the arable control plots; and Tits, Robins and Wrens were restricted to bordering hedgerows. There were however occasional small flocks of Chaffinches, Linnets and a record of a flock of 200 Goldfinches. Two species both of high conservation concern, Skylarks and Lapwings were also much more abundant in the arable controls than the SRC. Only one solitary Lapwing was recorded in the SRC during the three-year period of the study. However, monitoring of breeding birds within the same plots as part of the same study suggests that recently planted and recently harvested SRC may be better for birds such as Skylark than traditional arable crops. Unfortunately, at the start of the winter surveys in November 2001 the youngest SRC plots were those cutback nine months earlier. These plots would have grown sufficiently over the summer period to perhaps deter open species such as Skylark. No skylarks were present from any of the plots harvested in February 2004. However, only six plots were harvested in the final year, and each one was only monitored once at the end of the study, representing a small sample.

Snipe and Woodcock were regularly flushed from SRC plots during every year of the study. The number of Snipe present in SRC varied both between different winters and different plots. The variation in numbers between different winters is to be expected as Snipe respond quickly to adverse weather conditions by migrating south and west within the UK (Lack, 1986). The SRC plots may vary in their ability to support Snipe. Sage & Tucker (1998) found that snipe used SRC to roost during the day and flew off to feed in rushy or improved pasture at night. This behaviour is unsurprising as Snipe are mostly crepuscular, feeding at dawn and dusk (Tuck, 1972). SRC that provide the best protection against predators and are within reach of feeding areas are likely to be favoured. In this study, the highest numbers of Snipe were found at the site in Fogathorpe during the second winter. This site was replanted the previous spring and was fairly open with relatively wet ground conditions at the time, which could have provided both a suitable roosting and feeding site.

The results indicate that SRC plots are a suitable habitat for wintering Woodcock. The habitat requirements of Woodcock in the winter are less specific than during the breeding season, with patches of Gorse Ulex europaeus, Rhododendron Rhododendron and Willow Salix often holding them during the day (Hoodless, 1995). This species is nocturnal and feeds within permanent pasture or long-rotation grass leys within 1km of suitable roosting sites (Hirons & Bickford-Smith, 1983). Both the snipe and woodcock are quarry species and an understanding of their use of SRC may provide an opportunity to integrate management for biomass production with management for game interest (Sage & Tucker, 1998).

103 4.6 References

Baillie, S.R., Crick H.Q.P., Balmer D.E., Bashford R.I., Beaven L.P., Freeman S.N., Merchant J.H., Noble D.G., Raven M.J., Siriwadena G.M., Thewlis R. & Wernham C.V. (2001) Breeding birds in the wider countryside. Their conservation status 2000. BTO Research Report No 252, BTO, Thetford.

Berg, . (2002) Breeding birds on short rotation coppices on farmland in central Sweden-the importance of Salix height and adjacent habitats. Agriculture, Ecosystems & Environment, 90 (3): 265-276.

Bibby, C.J., Burgess, N.D. & Hill, D.A. (1992) Bird Census Techniques. Academic Press Limited, London.

Gregory, R.D., Wilkinson, N.I., Noble, D.G., Robinson, J.A., Brown, A.F., Hughes, J. Procter, D.A., Gibbons, D.W. & Galbraith, C.A. (2002) The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002-2007. British Birds 95: 410-450.

Henderson, I.G., Vickery, J.A. & Carter, N. (in press). The use of winter bird crops by farmland birds in lowland England. Biological Conservation.

Hirons, G. & Bickford-Smith, P. (1983).The diet and behaviour of Eurasion Woodcock wintering in Cornwall. In Kalchreuter, H., Proc. 2nd European Woodcock and Snipe Workshop, pp. 11-17. Slimbridge.

Hoodless, A.N. (1995). Studies of Eurasian Woodcock. British Birds. 88 (12): no.12, 578-592

Lack, P. (1986) The Atlas of wintering birds in Britain and Ireland. T& A.D. Poyser Ltd, Staffordshire, England.

Moorcroft, D., Whittingham M.J., Bradbury R.B. & Wilson J.D. (2002) The selection of stubble fields by wintering granivorous birds reflects vegetation cover and food abundance. Journal of Applied Ecology. 39: 535-547.

Sage, R.B. (1999) Weed competition in willow coppice crops: the cause and extent of yield losses. Weed Research 39: 399-411.

Thompson, D.L., Baillie S.R., Peach W.J. (1997) The demography and age specific annual survival of song thrushes during periods of stability and decline. Journalof Animal Ecology. 66: 414-424.

104 Tuck, L.M. (1972) The snipes: a study of the genus Capella. Canadian Wildlife Service Monograph Series No 5, Ottawa. 429 pages.

Siriwardena, G.M., Baillie, S.R., Crick, H.Q.P. & Wilson, J.D. (1998) Variation in the survival rates of some British passerines with respect to their population trends on farmland. Bird Study. 45: 276-292.

Weins, J.A. (1989) The Ecology of Bird Communities. Cambridge University Press, Cambridge.

Wilson, P.J. (1992) Britains Arable Weeds. British Wildlife3: 149-16

105 4.7 Appendix 1

Species Control Young SRC Established SRC Mean Mean Mean % visits % visits % visits no per no per no per present present present visit visit visit Barn Owl 0 0 4 0.04 0 0 Blackbird 4 0.06 57 1.43 58 1.17 Black headed Gull 3 0.39 0 0 0 0 Blue Tit 6 0.08 32 0.76 51 1.37 Bullfinch 0 0 7 0.09 2 0.05 Carrion crow 8 0.31 18 0.11 0 0 Chaffinch 13 0.44 59 3.32 42 1.95 Dunnock 4 0.05 19 0.31 27 0.32 Fieldfare 9 0.77 16 1.37 8 0.51 Golden Plover 1 0.06 0 0 0 0 Goldfinch 6 2.77 7 0.17 2 0.03 Gt. Sp.Woodpecker 0 0 1 0.01 0 0 Great Tit 2 0.02 10 0.12 12 0.17 Gr. Woodpecker 0 0 1 0.01 0 0.17 Greenfinch 4 0.15 21 0.43 0 0 Grey Partridge 1 0.19 5 0.23 0 0 Jackdaw 0 0 1 0.02 0 0 Herring Gull 4 1.38 0 0 0 0 Kestrel 3 0.03 3 0.04 0 0 Lapwing 6 0.75 1 0.01 0 0 L. Blackbacked Gull 3 0.28 0 0 0 0 Linnet 6 0.35 16 0.28 2 0.17 Long Tailed Tit 1 0.01 4 0.09 15 0.69 Magpie 3 0.04 4 0.04 3 0.05 Mallad 0 0 1 0.01 0 0 Meadow Pipit 6 0.32 28 0.69 2 0.03 Mistle Thrush 1 0.03 4 0.06 0 0 Pheasant 9 0.33 48 1.41 52 1.36 Pied Wagtail 2 0.02 5 0.05 0 0 Red Leg. Partridge 6 0.51 22 1.20 8 0.30 Redshank 1 0.01 2 0.06 0 0 Redwing 4 0.04 28 1.63 12 0.63 Reed Bunting 4 0.07 33 1.76 15 0.24 Robin 4 0.06 18 0.22 15 0.19 Rook 0 0.16 5 0.09 0 0 Siskin 0 0 2 0.10 0 0 Skylark 26 1.45 21 0.64 0 0 Snipe 9 0.33 31 1.27 15 0.30 Song Thrush 1 0 16 0.28 2 0.03 Sparrowhawk 2 0.02 1 0.04 2 0.01 Starling 3 0.17 4 0.15 2 0.03 Stock Dove 4 0.54 1 0.01 0 0 Tree Sparrow 1 0.02 2 0.10 2 0.02 Woodcock 1 0.01 21 0.26 22 0.25 Wood Pigeon 14 4.54 9 0.20 0 0 Wren 3 0.05 38 0.79 30 0.32 Yellowhammer 11 0.27 32 2.33 2 0.05 Table 4.1 Species recorded in the 12 SRC and arable control plots for the four winter surveys (November, December, January and February) undertaken during three consecutive years of the study. The table shows the percentage of visits each individual species was recorded and the mean number of individuals of each species recorded per visit.

106 Appendix 2

Species Presence Conservation Status Barn Owl * ++ Amber Black headed Gull + Amber Bullfinch ++ Red Dunnock ++ Amber Fieldfare ++ Amber Grey Partridge * Red Herring Gull* + Amber Kestrel Amber Linnet ++ Red Lapwing* + Amber Mistle Thrush ++ Amber Meadow Pipit ++ Amber Redshank* ++ Amber Redwing ++ Amber Reed Bunting ++ Red Skylark* + Red Snipe ++ Amber Song Thrush ++ Red Starling Red Tree Sparrow ++ Red Woodcock ++ Amber Yellowhammer ++ Red

Table 4.2 Conservation status of birds recorded during winter visits to SRC and arable plots (from RSPB, 2000). Red list species are those with a rapid (more than 50%) decline in the UK breeding population over the last 25 years. Amber list species are those that have experienced a moderate decline (25-49%) in the UK breeding population in the last 25 years. Presence ++ more frequently recorded in SRC than arable controls + more frequently recorded in arable controls than SRC * = Species not recorded in established SRC (>1 years growth)

107 5 BUTTERFLY MONITORING

5.1 Summary

Butterflies using twelve short rotation willow coppices (SRC) and paired arable controls were monitored three times each year: May/June, June/July and July/August. Numbers of species groups and total numbers of butterflies were related to habitat and coppice age.

All species groups had more butterflies in the coppice than on the arable sites. On both the coppice and arable sites, the ’Whites' species group was dominant in the first round. The ’Browns' generally became more abundant in the second and third rounds. This reflected the flight times of the different species groups rather than habitat preference. ’Skippers' and ’Blues' were less common but increased in abundance in the SRC in late summer.

Twenty-two species of butterfly were found over the four years. All occurred on both the coppice and arable controls. All species are relatively common with low conservation priority. The Meadow Brown was the most abundant species seen. Both the number of butterfly individuals and the number of butterfly species present on the coppice, increased over the four years.

Total butterfly numbers on the coppice and the arable sites showed no significant differences in the first rounds. The majority of second and third rounds had significantly more butterflies present on the coppice compared to their arable pairs.

Significantly higher numbers of butterflies were seen in coppices planted in 1999 compared to their arable pairs. These higher numbers of butterflies on the coppice were only found on the 2000-planted coppices after two years of growth.

The majority of butterflies were seen in the headlands on both the coppice and arable sites. The relatively unmanaged headlands of the willow coppice provided a better habitat for butterflies. Vegetation within these areas provided food plants for both adults and caterpillars, and was important in determining butterfly species present.

’Whites' and ’Aristocrats' are highly mobile, feeding on a variety of plant species and probably move between the coppice and arable habitats. ’Browns' and ’Skippers' form colonies associated with a variety of grass species. The unmanaged grass headlands of short rotation coppices provide a good breeding habitat for these species. As the ground vegetation developed, the number of butterfly individuals and species increased.

A favourable microclimate (improved shelter, warmth and humidity) is provided by surrounding hedgerows as well as the coppice itself, and also contribute to increased butterfly diversity.

108 It is recommended that short rotation willow coppices are planted near hedgerows and woodlands, and managed to contain a variety of different growth stages in order to provide a range of habitat conditions. Ground vegetation should be allowed to develop and management by spraying and cutting kept to a minimum.

5.2 Introduction

Butterflies are the most well known group of British invertebrates though most species of butterfly have declined in recent years due to agricultural intensification, the loss of native grasslands and a decline in active coppice management in traditional woodlands (Sage et al,1994).

Approximately 70% of Britain's resident butterfly species regularly breed in woodlands (Sage, 1998), and about 33% are confined to the woodland habitat (Sage et al, 1994). Most of these species are generally associated with the woodland edges, headlands and the open areas provided by rides or glades rather than the trees themselves. In these areas an herb-rich ground flora attracts butterflies for feeding and reproduction (Sage et al, 1994). Although SRC plantations are planted at high densities with fast-growing species of willows, access to the sites for regular management and harvesting means open areas such as headlands and rides are often incorporated into the plantation planting design. These areas have the potential to become valuable habitats for butterflies.

Previous studies of butterflies on farmland have shown that butterfly fauna is limited, with crops on arable land being suitable only for the butterfly pests of brassicas (Sparks and Parish, 1995; Thomas, 1984 cited in Dover, 1996). Agri environment schemes encourage the provision of headlands and uncropped areas within the arable rotation, to benefit wildlife and increase biodiversity in the arable landscape. However, the development of the energy crop industry and the need to supply enough willow coppice for fuel, may lead to large areas of new short rotation coppice (SRC) plantations being established on arable sites. These new areas of woodland may have important impacts on local habitats and biodiversity.

Although studies have been undertaken to determine the effects of SRC on bird and plant communities, little work has been done to investigate the impact upon butterflies, which are often regarded as good indicators of the status of other, less conspicuous invertebrates (Sage et al, 1994). Thus, there are three objectives of the project: firstly, to identify and describe the butterflies using the short rotation coppice plots, secondly, to describe the butterflies using the adjacent arable control plots and to take this as being representative of the butterfly community present on the plots before conversion willow coppice. Using the information obtained from the first two objectives, the third, to give guidance on the impact of future large commercial SCR developments on butterfly biodiversity can be achieved.

109 5.3 Methods

Each of the SRC and arable control plots were monitored three times during each year: the first round was completed in May/June, the second round in June/July and the third round in July/August. Although every attempt was made to complete the Monitoring during the same weeks each year, periods of bad weather occasionally led to delayed visits (Table 5.1).

\ 2000 2001 2002 2003

Planting 1 2 3 1 2 3 1 2 3 1 2 3 year

Paddock 1999 15/06 13/07 23/08 22/05 21/06 20/08 17/05 18/06 07/08 29/05 20/06 23/07 House

Charity 1999 22/05 27/06 17/08 24/05 20/06 14/08 16/05 17/06 29/07 28/05 16/06 22/07 Farm

Hawthorne 1999 15/06 13/07 24/08 22/05 21/06 16/08 31/05 18/06 07/08 29/05 20/06 23/07 House

Ellerker 1999 12/06 12/07 22/08 23/05 20/06 14/08 16/05 17/06 06/08 21/05 16/06 22/07

Far Shires 1999 16/05 20/06 15/08 25/05 18/06 09/08 23/05 20/06 05/08 19/05 20/06 21/07

West Farm 1999 13/06 28/06 11/08 30/05 22/06 15/08 28/05 20/06 30/07 19/05 16/06 23/07

Foggathorpe 2000/01 31/05 26/06 16/08 FMD FMD FMD 17/05 19/06 30/07 27/05 17/06 24/07

Howden 2000 14/06 27/06 18/08 24/05 21/06 15/08 21/05 19/06 29/07 28/05 17/06 24/07

North 2000 24/05 27/06 10/08 30/05 22/06 10/08 17/05 18/06 29/07 28/05 17/06 24/07 Duffield

Oak Farm 2000 31/05 26/06 16/08 13/06 22/06 13/08 20/05 19/06 30/07 27/05 17/06 24/07

Shire Oaks 2000 07/06 20/06 15/08 FMD FMD FMD 23/05 20/06 05/08 19/05 19/06 21/07

South Cave 2000 08/06 12/07 22/08 23/05 20/06 14/08 16/05 17/06 06/08 21/05 16/06 22/07

Table 5.1: Site survey dates 2000 to 2003 inclusive.

110 The method used was based on the Butterfly Monitoring Scheme (Pollard & Yates, 1995). At each visit, transects comprising the margins of each SRC and arable plot were walked for the period of one hour, timed with a stopwatch, though if stops were made for butterfly identification, this extra time was added on. This time period for completing the transect was selected due to the highly variable size of the 12 sites; the largest site at West Farm required the full 60 minutes to complete one circuit whereas on smaller sites, the field margins were often walked more than once. Transects on the SRC and arable field pairs were always completed on the same day and were usually undertaken simultaneously by two observers. When this was not possible, the two sites were sampled in quick succession so that changes in weather had a minimal effect on the number and species of butterflies seen.

Transects were walked between 10:00 am and 17:00 pm on dry days when air temperatures exceeded 15°C and wind speeds were less than Force 4 on the Beaufort scale. Weather conditions were noted at the beginning and end of the sampling period. The number and species of all butterflies seen within a five-metre radius of the observer were recorded on a large-scale map of the field. Butterflies observed beyond the field boundary were ignored unless they crossed the field boundary within five metres of the observer. Where identification was difficult, the butterfly was caught in a hand net, identified and then released. On every visit to the site the time, transect starting point and direction of travel were noted on the field maps. The finishing location and time were also recorded.

In 2001, on the first visit in May, an alternative arable control site was selected at Paddock House Farm, as the original one had been planted with willow coppice. Also during 2001, the outbreak of Foot and Mouth Disease and resulting bio-security measures meant that the plots at Shire Oaks, which were located next to a pig unit, were not visited at any point during the season. Also, the SRC at Foggathorpe was ploughed and replanted with willow, as the original plantings had failed due to damage by crane-fly larvae (Tipula spp.). A nearby alternative was found but this also had to be abandoned due to its proximity to a stockyard. Thus, during 2001 only ten sites were monitored, six planted in 1999 and four in 2000.

In 2002, the arable control at West Farm decreased in size as part of the site had been turned over to permanent grass for horse grazing, and also a small farm woodland had been established. These areas were not included in subsequent butterfly counts, as they were not felt to be part of the arable rotation.

111 5.3.1 Data analysis

In order to determine differences in phenology between species, both within years and also between species, butterfly species were grouped as follows:

'Whites' Large White Pieris brassicae Small White Pieris rapae Green-veined White Pieris napi Orange-tip Anthocharis cardamines Clouded yellow Colias croceus Brimstone Gonepteryx rhamni

'Browns' Meadow Brown Maniola jurtina Ringlet Aphantopus hyperantus Wall Lasiommata megera Gatekeeper Pyronia tithonus Small heath Coenonympha pamphilus Speckled wood Pararge aegeria

'Aristocrats' Red admiral Vanessa atalanta Painted lady Cynthia cardui Small tortoiseshell Aglais urticae Peacock Inachis io Comma Polygonia c-album

'Blues' Small copper Lycaena phlaeas Common Blue Polyommatus icarus Holly Blue Celastrina argiolus

'Skippers' Small Skipper Thymelicus sylvestris Large Skipper Ochlodes venata

The data on numbers of species and individuals were logarithmically transformed and analysed using paired t-tests. The level of significance was taken as p 0.05. For comparisons between planting dates other than in the first year of the study, the site at Foggathorpe was omitted due to the replanting in 2001.

112 5.4 Results

5.4.1 Species groups

Summary

Overall, all species groups had more butterflies in the coppice than on the arable sites, though on a yearly basis, differences in numbers in the five butterfly groups between treatments were not always significant. In all years, the third round in July/August had the highest numbers of butterflies. 'Whites' were the most abundant species group in the first round, and 'Browns' tended to dominate the second and third rounds on both coppice and arable sites. 'Blues' and 'Skippers' although uncommon occurred more frequently in the coppice than the arable sites especially in late summer.

The grouping of butterfly species mentioned above (Section 5.2.1 Data analysis) was used to identify any differences in species composition present between coppice and arable fields, but also to highlight variations in the phenology of species.

2000

In the first round, 'Whites' were the most abundant species group with a total of 93 individuals counted on coppice and 53 on the arable plots. 'Aristocrats' and 'Browns' were seen in much lower number (coppice: 21 and 6; arable: 17 and 16 respectively) and no 'Blues' were recorded. Only the 'Aristocrats' had significantly more individuals on the coppice than on the arable controls (Table 5.2).

First round Second round Third round t11 = 3.09, p = Skippers NS NS <0.01 t11 = 2.46, p = Blues - - 0.02 t11 = 2.90, p = < t11 = 2.06, p = Aristocrats NS 0.01 0.03 t11 = 2.19, p = Browns NS NS 0.03 Whites NS NS NS

Table 5.2: Differences in number of butterflies in each species group found on coppice and arable controls in each round in 2000 (NS = Not significant. - = No butterflies seen)

During the second round, the numbers of 'Whites' declined and 'Browns' were most abundant. 'Aristocrats' and 'Skippers' also increased and again no 'Blues' were recorded. There was no significant difference in the number of individuals from any species group seen on the coppice and the arable plots.

113 In the third round in August, 'Browns' were still the most numerous species, though numbers had declined slightly, and 'Aristocrats' and Whites' increased. Blues' were recorded for the first time, with 95% of observations being made in the coppice (coppice: 20, arable: 1) (Figure 5.1). Only Whites' showed no significant difference in numbers between the coppice and arable treatments.

□ Whites 800 - □ Browns □ Aristocrats 700 - □ Blues ■ Skippers 600 -

500 -

400 -

300 -

200 -

100 -

Arable Arable Arable May/June June/July August Figure 5.1: Species composition and abundance of butterflies seen on coppice and arable control plots in 2000.

2001

During the first round, Whites' were again the most numerous species seen on the coppice, with fewer 'Browns' and Aristocrats' present. No Skippers' or Blues' were counted. On the arable controls however, Aristocrats' were more common than 'Whites'; numbers of Aristocrats' were significantly higher on the arable plots (Table 5.3). 'Browns' occurred in similar numbers to the coppice.______First round Second round Third round t9 = 3.10, p = Skippers - NS <0.01

Blues - - NS

tg = -2.80, p = Aristocrats NS NS 0.01

tg = 6.30, p = Browns NS NS <0.01 Whites NS NS NS

Table 5.3: Differences in number of butterflies in each species group found on coppice and arable controls in each round in 2001 (NS = Not significant. - = No butterflies seen)

114 Numbers of butterflies were lower in the second round. Although the number of species increased slightly on the coppice, they dropped on the arable plots (9 and 4 species respectively). 'Aristocrats', 'Whites' and 'Browns' all showed a reduction in numbers. Skippers' were present though only a few individuals were seen (a total of 11 and 5 species on coppice and arable respectively). There was no significant difference in the number of individuals of each species group on coppice and arable

Numbers of all species groups increased during the August round, with 'Whites' being the most abundant on the arable and 'Browns' on the coppice. Skippers' became slightly more numerous and Blues' were seen in very low numbers on both coppice and arable (6 and 5 species respectively) (Figure 5.2). Skippers' and 'Browns' had significantly more individuals on the coppice.

□Whites □ Browns 600 - □Aristocrats □ Blues 500 - ■ Skippers

400 -

300 -

200 -

100 -

SRC Arable SRC Arable SRC Arable May/June June August Figure 5.2: Species composition and abundance of butterflies seen on coppice and arable control plots in 2001.

2002

'Whites' were the most numerous species group on both the coppice and arable controls in the first round, though a similar number of 'Browns' were seen in the coppice. However, significantly more 'Browns' were seen on the coppice than the arable controls. For the first time, Blues' were seen during this round (Table 5.4)

115 First round Second round Third round t-n = 3.26, p = Skippers - NS <0.01 Blues NS NS NS Aristocrats NS NS NS t-n = 2.16, p = t-n = 4.15, p = t-n = 4.31, p = Browns 0.03 <0.01 <0.01 Whites NS NS NS

Table 5.4: Differences in number of butterflies in each species group found on coppice and arable controls in each round in 2002 (NS = Not significant. - = No butterflies seen)

Numbers of individuals and species had increased by the June count, with the 'Browns' becoming the dominant species group; eight times more were seen on the coppice than in the arable (484 and 58 respectively). 'Aristocrat' and 'White' numbers decreased, but 'Skippers' were relatively abundant compared to previous years, with significantly higher numbers on the coppice.

In the third round, the numbers of butterflies in all species groups increased, though the 'Browns' were still dominant, with more present on the coppice than the arable. Only the Blues' had higher numbers on the arable than the coppice (coppice: 1, arable: 6). The numbers of Aristocrats' were similar on both habitats (coppice: 57, arable: 54) (Figure 5.3).

□ Whites 1400 - □ Browns □ Aristocrats 1200 - □ Blues ■ Skippers

1000 -

800 -

600 -

400 -

200 -

SRC Arable SRC Arable SRC Arable May June July/August Figure 5.3: Species composition and abundance of butterflies seen on coppice and arable control plots in 2002.

116 2003

During May, 'Whites' were the most frequently seen species group on both the coppice and arable sites, with more being counted on the controls (coppice: 64, arable: 92). Browns' were the next most abundant group (coppice: 46; arable: 19). A low number of Blues' were counted on both treatments (coppice: 2; arable: 4). There were no significant differences in butterfly numbers between coppice and their arable pairs for any species group (Table 5.5).

First round Second round Third round tn = 3.56, p = t,1 = 4.93, p = Skippers - <0.01 <0.01 Blues NS NS NS t11 = 2.82, p = Aristocrats NS NS <0.01 t11 = 4.22, p = t11 = 7.87, p = Browns NS <0.01 <0.01 t,1 = 2.13, p = Whites NS NS 0.03

Table 5.5: Differences in number of butterflies in each species group found on coppice and arable controls in each round in 2003 (NS = Not significant. - = No butterflies seen).

The June observations showed a similar pattern to previous years, with Browns' dominating on both the coppice and arable (915 and 126 respectively). Bkippers' were the second most numerous group with 111 individuals counted on the coppice compared to 13 on the arable. The differences in butterfly numbers on coppice and arable plots were significant for both these species groups. The number of Blues' halved to three, all being seen on the coppice. The number of Whites' recorded declined on both coppice and arable sites (18 and 16 respectively).

The final round in July was again dominated by Browns' though numbers of \Aristocrats' and Whites' and Blues' also increased. Numbers of Bkippers' declined. For all groups, more individuals were found in the coppice than in the arable control plots, and this difference was significant for all apart from the Blues' (Figure 5.4).

117 2500

□ Whites □ Browns 2000 - □ Aristocrats □ Blues ■ Skippers 1500 -

1000 -

500 -

Arable Arable Arable

Figure 5.4: Species composition and abundance of butterflies seen on coppice and arable control plots in 2003.

5.4.2 Species and individual numbers

Summary

A total of 11281 butterflies of 22 species were seen over the four years. All species were seen on both coppice and arable control plots. In all years, significantly more species were seen on the coppice than the arable. In only two rounds: the second in 2000 and the first in 2001, were more butterfly individuals seen on the arable controls, but in both instances these differences were not significant. Butterfly numbers on the coppice and arable sites showed no significant differences during the first rounds. Apart from the second round in 2000, all other second and third round recordings showed that significantly more butterflies were present on the coppice sites compared to the arable sites.

A total of 11281 butterflies of 22 species were seen during the four-year study. All of these species were observed in both the coppice plots and the arable control plots at some point over the four years. Both the mean number of species and individuals counted on each visit every year increased over the study period. (Figures 5.5; 5.6). Clouded Yellow was the only species recorded in only one year (2000: 4 individuals) and it was also the only species not recorded in the last two years of the study. Meadow Browns were seen every year and this was the most abundant species overall, with a total of 2890 individuals counted.

118 8

Arable Arable Arable Arable 2000 2001 2002 2003 Figure 5.5: Mean number (+ 1 s.e.) of species found during each monitoring round each year, on coppice and arable control sites.

SRC Arable SRC Arable SRC Arable SRC Arable 2000 2001 2002 2003 Figure 5.6: Mean number (+1 s.e.) of individuals seen during each monitoring round each year, on coppice and arable control sites.

119 2000

In 2000, a total of 2378 butterflies were observed of which 2312 (97.22%) were identified to species. Eighteen different species of butterfly were recorded in total, with numbers rising from a minimum of 11 and 9 in the first round, in the coppice and arable respectively, to 17 and 14 in the last round in August (Table 5.6). On average, 5.4 (± 0.49) butterfly species were counted on each visit to a coppice site and 4.3 (± 0.32) butterfly species on arable sites. This difference in number of species is significant (t35 = 2.15, p = 0.02).

First round Second round Third round Coppice Arable Coppice Arable Coppice Arable Total Species 11 9 15 14 17 14 18 Individuals 133 77 452 522 771 423 2378

Table 5.6: Results of 2000 observations

Of the 2378 butterflies recorded, 1356 were on the coppice and 1022 on the arable controls over the three rounds. Averages of 37.7 (± 6.2) individuals were counted on the coppice sites and 28.39 (± 5.8) individuals on the arable control fields. Overall, the difference in numbers counted on the coppice and arable plots was significant (t35 = 2.04, p = 0.02). Although the coppice had higher numbers of butterflies in the first and third rounds, more individuals were recorded on the arable control plots in the second round. This difference in numbers on the coppice and controls in each round was only significant in the third round (t11 = 2.70, p = 0.01).

2001

A total of 1459 butterflies were seen with 1453 (99.6%) identified to species. Nineteen species of butterfly were observed, with numbers increasing overall from seven on both the coppice and arable in the first round, to 15, again on both areas, in the third round. Number of species declined on the controls during the second round (Table 5.7). On average, 4.5 (± 0.6) and 4.1 (± 0.5) species were recorded on the coppice and arable fields respectively. The difference in number of species was not significant (t29 = 1.09, p = 0.14).

First round Second round Third round Coppice Arable Coppice Arable Coppice Arable Total Species 7 7 9 4 15 15 19 Individuals 152 192 42 15 665 393 1459

Table 5.7: Results of 2001 observations

More butterflies were counted on the coppice compared to the arable and this difference in number of individuals was significant (t29 = 2.14, p = 0.02). More butterflies were seen on the coppice during the second and third rounds, while more were present on the arable fields in the May round. These differences were not significant in the first round (t9 = -0.48, p = 0.32), but were in the second (t9 = 2.06, p = 0.03) and in the third (t9 = 4.52, p = <0.01).

120 2002

A total of 3508 butterflies were counted over the three observation periods, with 3477 (99.1%) identified to species. Twenty-one species were counted in the season, again increasing from May to July. In the first round, ten species were recorded in both coppice and arable. In the third round, the arable sites had more species, 14 compared to 13 on the coppice (Table 5.8). On average, 5.6 (± 0.4) and 4.9 (± 0.5) species were counted on the coppice and arable respectively, and this difference was significant (t35 = 2.21, p = 0.02).

First round Second round Third round Coppice Arable Coppice Arable Coppice Arable Total Species 10 10 13 10 13 14 21 Individuals 382 302 620 145 1410 649 3508

Table 5.8: Results of 2002 observations

Once again, numbers of butterflies increased over the season, and in all three monitoring periods, more were seen on the coppice than in the arable control plots. This difference was significant in the June and July rounds (t11 = 4.08, p = <0.01; t11 = 3.52, p = <0.01 respectively). An average of 67 (± 12.7) and 30.4 (± 5.4) individuals were recorded on the coppice and arable fields respectively, and overall, significantly more were seen on the coppice (t35 = 3.95, p = <0.01).

2003

In the fourth and final year 4476 butterflies were counted throughout the season with 4473 (99.9%) identified to species. As in 2002, 21 species of butterfly were observed in total, with numbers increasing steadily throughout the summer from 12 on the coppice and eight on the controls in the first round, to 18 on the coppice and 16 on the controls in the final round (Table 5.9). The coppice had a higher number of species throughout, with an average of 6.9 (± 0.6) on the coppice at each site and 5.1 (± 0.4) species on the arable. There was a difference in the number of species recorded between treatments with the coppice having significantly more (t35 = 4.68, p = <0.01)

First round Second round Third round Coppice Arable Coppice Arable Coppice Arable Total Species 12 8 15 14 18 16 21 Individuals 125 138 1098 241 2111 763 4476

Table 5.9: Results of 2003 observations Once again, numbers of butterflies increased over the season, and in all three monitoring periods; more individuals were seen on the coppice than the arable sites.

121 However this difference was not significant in the first round (t„ = 0.60, p = 0.28), but was significant in both the second and third rounds (t„ = 3.41, p = <0.01 and t„ = 5.44, p = <0.01 respectively). An average of 92.6 (± 16.0) individuals were seen on coppice site and 31.7 (± 6.4) on the arable sites. Overall, a significantly higher number of individuals were recorded on the coppice (t35 = 4.54, p = <0.01).

5.4.3 Numbers of butterflies in coppice of known age and their arable controls.

Summary

Significantly higher numbers of butterflies were seen in coppices planted in 1999 than in their paired arable controls throughout the four years. Coppices planted in 2000 had similar numbers of butterflies as their arable pairs in the first two years of the study. In 2002 and 2003 however, significantly more were seen within the coppice.

1999

More butterflies were seen in the coppice plots planted in 1999 than in their paired arable controls throughout the whole of the study (Figure 5.7). Although numbers declined on both the coppice and arable plots in the second year of the project, the overall trend showed an increase in butterflies over the four years. The differences in numbers between the coppice and arable controls were significant in every year (2000: t17 = 3.98, p = <0.01; 2001: t17 = 4.11, p = <0.01; 2002: t17 = 5.08, p = <0.01; 2003: t17 = 3.16, p = <0.01).

SRC Arable SRC Arable SRC Arable SRC Arable 2000 2001 2002 2003 Figure 5.7: Mean number of butterflies (+ 1 s.e.) found at each monitoring round, in coppice planted in 1999 compared to arable controls.

122 2000

During the first year of the study, fewer butterflies were seen on the coppice than on the arable, although this difference was only 20 individuals and was not statistically significant (t17 = -0.42, p = 0.34). During 2001, only four sites could be surveyed due to FMD so numbers of butterflies were lower, though individuals counted on the remaining sites, particularly in the last round raised the mean number seen. Although more were seen on the coppice, this difference was not significant (t11 = - 0.94, p = 0.18). In 2002 and 2003, five sites were monitored due to the exclusion of Foggathorpe, which had been replanted. In both years, butterfly numbers increased and significantly more were counted on the coppice than in the arable controls (2002: t14 = 10.22, p = <0.01; 2003: t14 = 10.96, p = <0.01) (Figure 5.8).

Arable Arable Arable Arable

Figure 5.8: Mean number of butterflies (+ 1 s.e.) found at each monitoring round, in coppice planted in 2000 compared to their arable controls.

5.4.4 Comparison of numbers of butterflies and species at the beginning and end of the project.

Summary

Both the number of butterfly individuals and the number of butterfly species present on the coppice, increased from the start of the project in 2000, when the coppice was newly planted or recently cut, to the end of the project in 2004, when the coppice was mature and awaiting harvest. There was no obvious pattern of increase in the control plots

During the first year of the project, a total of 1356 individual butterflies (average of 37.67 ± 6.15 individuals on each visit to a site), of 18 species (average of 5.44 ± 0.49 species on each visit to a site) were recorded on the coppice.

123 In the final year of the project, in 2003, both the number of individuals and species recorded had risen. A total of 3334 individuals (average 92.61 ± 16.02), of 21 species (average 6.94 ± 0.57), were seen throughout the three monitoring periods. The increases in both the number of individuals butterflies and species between the start and the end of the project were significant (individuals: t35 = -2.21, p = 0.02; species: t35 = -2.52, p=<0.01).

Changes in the numbers and species of butterfly found on the arable fields were not statistically tested, due to changes in crop occurring on most of the fields each year. Some crop, such as oilseed rape and borage attracted more butterflies, so making any comparisons of changes in butterfly numbers or species composition over the four years impossible to interpret.

5.5 Discussion

A maximum of 22 species of butterfly were found on both the coppice and arable control sites. All of these species are relatively common and widespread with low conservation priority (Butterfly Conservation website).

In all years, both treatments were dominated by species of ’Whites' and ’Browns', though changes in species group dominance reflected differences in the ecology of the butterfly species, that is, differences in timing in flight periods, rather than the influence of the coppice or arable habitat. The first brood of ’Whites', which generally overwinter as chrysalides, appear in flight from May, while second broods appear in July (Lewington, 2003). The peaks of ’White' species at our study sites correspond with these flight times. In the first round of observations, ’Browns' are dominated by Wall butterflies, which overwinter as caterpillars, with a second brood from mid-July. Other ’Browns' have a single flight period from June until August/September (Lewington ,2003). ’Skippers' also only have one flight period: from June until September. The flight periods of all these species groups can clearly be seen on both the coppice and arable controls.

Within these flight periods however, differences in the total numbers of butterflies in each species group recorded on coppice and arable plots were observed. Apart from the third round monitoring in 2003, there were no significant differences in the number of ’Whites' seen on the two treatments. The total number of ’Aristocrats' recorded during each monitoring period were more variable, though generally also showed no significant differences in numbers on coppice and arable controls. Butterflies within these two species groups are highly mobile, and feed on a variety of plant species that are associated with disturbed ground (Sage et a!., 1994). These species probably move between the coppice and arable habitats in search of suitable plant species for feeding and reproduction.

’Browns' and ’Skippers', had flight periods tending to correspond with observations made in June/July and July/August. In general, significantly more individuals were seen on the coppice than the arable sites. These species form colonies associated

124 with stress-tolerant grasses, the larval food plants (Sage et al, 1994). These grass species are common in the coppice, developing along the margins and headlands left unplanted by willows, to allow access for management and harvesting. These margins are also generally left unmanaged. For ’Skippers' in particular, this unmanaged long grass is essential as they overwinter as caterpillars on the vegetation (Lewington, 2003). Cutting of the grass, particularly in the summer and autumn, destroys this essential habitat.

Thus, the change of land use from arable cropping to willow coppice did not affect the phenology of the recorded butterfly groups. The ground vegetation that developed in the headlands was used by the more mobile ’Aristocrat' and ’White' species, though these species probably moved between the coppice and arable habitats. Significantly more ’Browns' and ’Skippers' were seen in the coppice. These species are less mobile and more dependent on the unmanaged vegetation that develops in the coppice margins.

The total numbers of species and individuals seen each year, and the mean numbers of species and individuals seen at each visit, showed an overall increase on both the coppice and arable sites, in the four years of the study. However, greater increases were apparent on the coppice and these can be related to the development of the coppices as an important butterfly habitat, primarily due to the establishment of a varied ground fauna providing nectar-producing flowers, such as thistles (Cirsium spp.), and food plants for larvae. Although margins were present in the arable fields, these were generally narrow (approximately 2m) buffers adjacent to hedgerows and ditches. These areas attracted the majority of butterflies seen in the arable controls, but did not support the numbers found in the wider (5-6m) and unmanaged margins of the coppice. It is likely that the uncultivated margins on the arable fields received some spray drift from routine applications of herbicides, insecticides and fertilisers, and these may have affected butterfly species, either directly by killing caterpillars, or indirectly by killing suitable food plants (Langley and Sotherton, 1997). On SRC, herbicides are usually applied during the first year of willow growth, to reduce competition for light and nutrients from ’weed' species. This would contribute to the lower numbers of butterflies found in the first year of the project. Establishment of ground flora after herbicide applications ceased would encourage higher butterfly numbers in subsequent years.

The arable control at Oak Farm was under setaside for the duration of the project, and attracted higher numbers of butterflies than many of the other arable sites. However, it generally had lower numbers of butterflies than its coppice pair, and those that were seen were generally close to the surrounding hedgerows. This higher butterfly abundance near hedgerows was noted on the majority of the coppice and arable sites. Hedgerows usually have uncultivated verges containing butterfly food plants but themselves contain plants that attract butterflies, such as Ivy (Hedera) for the Holly Blue (Thomas, 1986, cited in Sparks and Parish, 1995).

Not only is the floral composition of hedges important to butterflies, but also its structure, in terms of providing a suitable micro-climate by increasing shelter, warmth and humidity (Dover, 1996). Within short-rotation coppice, this micro

125 habitat is provided not only by the enclosing boundary hedgerows but also by the crop itself. This structural benefit increases as the crop develops, so attracting greater numbers of butterflies. The coppice at West Farm contained very high numbers of butterflies compared to its arable pair and also most of the other coppice sites visited. The site was made up of a number of small compartments surrounded by hedgerows, which provided numerous uncultivated corners favoured by the butterflies for the increased ground vegetation but also for their shelter and higher temperatures. Charity Farm was the only site of the twelve, which had no hedgerows on either the coppice or arable plots. The majority of butterflies were found along the shared boundary made up of tall ’weedy' vegetation, which provided food plants but also shelter.

The importance of ground flora and shelter in determining butterfly numbers can further be seen by comparing butterflies within coppice of a known age with arable fields. Coppice plots planted in 1999 had higher butterfly numbers than their arable controls in all four years. In the first year of the project, the willow on these plots had recently been cut, so although the trees themselves would not have contributed to providing shelter, the surrounding hedgerows and developing ground flora would have attracted butterflies. For plots planted in 2000, the mean number of butterflies was lower on the coppice than the arable in the first year of observations. This was probably due to the ground preparation that was undertaken before the coppice was planted. Ploughing the plots would have destroyed much of the ground flora that would have attracted butterflies. In 2001, two of the sites could not be visited. However, herbicide treatments in the four that were monitored and the late planting of three of the coppice plots resulted in poor ground flora and lower numbers of butterflies. In both 2002 and 2003, butterfly numbers increased as the crop grew and the ground vegetation developed.

Although numbers and species of butterflies increased over the four years, this trend was disrupted by a reduction in both numbers and species in 2001. Foot and Mouth biosecurity measures reduced the number of 2000 coppice plots and their arable control visited to four, and this led to lower numbers of butterflies recorded. However, this reduction was also apparent on all six of the 1999 coppice sites. This reduction may have occurred as a result of the wet conditions experienced during the autumn of 2000; the autumn was one of the wettest on record since 1766 (Branson, 2001). These conditions may have combined with poor breeding success in 1999 and 2000 and led to reduced butterfly numbers in 2001 (Bowles, 2001).

This four year study has shown that over 30% of Britain's resident butterfly species can be found on both commercial short-rotation willow coppice and arable fields, though higher numbers of individuals are seen on the coppice. This difference in numbers between coppice and arable plots is due primarily to the high numbers of ’Browns' and ’Skippers' within the coppice plots. As found in previous studies of butterflies on arable fields, very few individuals were found within the crop itself; the majority were found along the field margins. This distribution was also found within the coppice; no British butterfly uses willow as a food plant. The margins of both the coppice and arable fields support an ground flora that provide nectar for feeding adults and food plants for caterpillars. However, margins on arable fields are

126 usually narrow, subject to chemical spray drift and routine management such as cutting, all of which can be detrimental to butterflies. The margins of coppice are generally wider to allow access, and although herbicides are applied in the first year of willow growth, the margins are generally left unmanaged. Hedge boundaries provide shelter around arable fields, but within the coppice, the willow trees themselves contribute to creating a beneficial microclimate. The benefits of SRC to the butterfly community develop as the trees grow and the ground flora becomes established.

Large commercial SRC developments should benefit the butterfly community as long as margins and headlands are incorporated into their design. A varied ground flora should be allowed to develop and management by spraying and cutting kept to a minimum. Positioning new coppices adjacent to hedgerows help to provide a sheltered environment and also offer extend corridors for the movement of butterflies and other wildlife from one habitat to another. The structure of SRC encourages butterflies, as it is able to provide sheltered rides and headlands, which are generally absent from traditional arable crops. Internal hedges, and splitting the coppice into different compartments, preferably of different growth stages, will encourage a greater range of habitat conditions and also a greater diversity of butterflies.

5.6 References

Asher J., Warren M., Fox R., Harding P., Jeffcoate G. & Jeff coate S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford.

Bowles N. (2001) Butterflies. British Wildlife 12(6): 433.

Branson A. (2001) Weather reports of November and December 2000. British Wildlife Mi'S)-. 201.

Butterfly Conservation www.butterfly-conservaion.org

Dover J.W. (1996) Factors affecting the distribution of satyrid butterflies on arable farmland. Journal of Applied Ecology 33: 723-734.

Lewington R. (2003) Pocket Guide to the Butterflies of Great Britain and Ireland. British Wildlife Publishing, Hampshire.

Longley M. & Sotherton N.W. (1997) Factors determining the effects of pesticides upon butterflies inhabiting arable farmland. Agriculture, Ecosystems and Environment 61: 1-12.

Pollard E. & Yates T.J. (1995) Monitoring Butterflies for Ecology and Conservation. Chapman & Hall, London.

127 Sage R.B. (1998) Shirt rotation coppice for energy: towards ecological guidelines. Biomass andBioenergy15 (1): 39-47.

Sage R.B, Robertson P.A. & Poulson J.G. (1994) Enhancing the conservation value of short rotation biomass coppice- Phase 1 the identification of wildlife conservation potential. Report of the Energy Technology Support Unit, Department of Trade and industry

Sparks T.H. & Parish T. (1995) Factors affecting the abundance of butterflies in field boundaries in Swavesey Fens, Cambridgeshire, UK. Biological Conservation 73: 221-227.

128 5.7 Appendix

Butterflies recorded on coppice and arable control sites over the four years of the project. ______2000 2001 2002 2003 Species SRC Control SRC Control SRC Control SRC Control Total

Large White 34 29 64 43 107 102 165 183 727

Small White 175 132 126 160 77 100 93 65 928 Green-veined 42 37 109 102 330 266 334 218 1438 White Orange-tip 6 7 45 7 37 20 11 13 146 Clouded 3 1 0 0 0 0 0 0 4 yellow Brimstone 0 0 5 0 0 1 2 0 8 Meadow 275 287 59 16 684 112 1221 236 2890 Brown Ringlet 98 115 2 2 94 34 309 33 687

Wall 294 122 149 73 188 74 82 29 1011

Gatekeeper 46 50 76 24 465 122 637 114 1534

Small heath 10 4 1 0 5 0 21 1 42 Speckled 0 0 0 1 1 0 0 1 3 wood Red admiral 15 29 2 2 0 1 26 7 82

Painted lady 54 11 1 0 7 7 57 39 176 Small 514 40 28 14 52 55 102 88 135 tortoiseshell Peacock 142 66 150 98 94 68 102 39 759

Comma 0 0 0 4 1 0 4 1 10

Small copper 12 1 6 5 2 6 5 8 45 Common 8 0 0 0 4 4 8 0 24 Blue Holly Blue 0 0 0 0 0 1 0 2 3

Small Skipper 36 13 31 2 152 17 75 5 331

Large Skipper 32 58 15 7 95 42 94 10 353 Unidentified 30 23 3 2 14 15 0 2 89 White Unidentified 4 8 0 0 0 2 0 0 14 Brown Unidentified 0 1 0 0 0 0 0 0 1 Skipper Unidentified 0 0 1 0 0 0 0 1 2 Aristocrat Total 1356 1022 859 600 2412 1096 3334 1142 11821

129 6. GENERAL INVERTEBRATE MONITORING

6.1 Summary

Invertebrates were collected from short rotation willow coppices in May/June and July/August each year. Total invertebrate numbers and orders were related to age of coppice and distance into the coppice.

The majority of invertebrates collected were Coleoptera or Hemiptera, and were the most abundant orders in both 1999-planted coppice and 2000-planted coppice. Other orders of invertebrates were found in lower numbers.

The mean number of invertebrate orders increased over the four years of the project. More orders of invertebrates were generally found during the second round of monitoring. In both age groups of coppice, the lowest mean numbers of invertebrate orders were usually either found at the edge or the centre of the crop. Distance points with the highest mean number of orders varied. No clear pattern of changes in mean number of invertebrate orders with distance into the coppice was apparent.

Numbers of invertebrates were higher in the second rounds of monitoring. The centre tended to have the lowest mean numbers in both 1999-planted and 2000- planted coppices. No significant pattern of distribution of invertebrate numbers with increasing distance into the coppice was apparent, although there was a tendency for there to be more in the edges and a decline towards the centre. Total numbers of invertebrates were highly variable between sites. Overall the species and invertebrate density was similar to that found previously (Sage & Tucker, 1997)

The Blue Willow Beetle (Phyllodecta vulgatissima) is an important pest of willow coppice and in high numbers can lead to economically significant yield losses. This species formed a large proportion of both total invertebrates and Coleoptera at the study sites. Numbers increased over the four years of the project, and higher numbers were present during the second rounds. Willow beetle numbers showed a varied distribution in relation to distance on both 1999-planted and 2000-planted coppices. Numbers of beetles were highly variable between sites.

An Abundance Index was based on the number of adult beetle per m2 was used to determine the severity of the willow beetle problem at the study sites. Only one of the 1999-planted coppice sites did not have willow beetle numbers at levels likely to result in severe yield loss. Only one coppice planted in 2000 had damaging levels of willow beetles.

Short rotation willow coppice is likely to increase local invertebrate biodiversity within the arable environment. Planting near to existing woodland and hedgerows extends these wildlife habitats and forms corridors for wildlife movement.

130 Isolated coppice sites appear to be less likely to develop damaging levels of willow beetles. Leaving headlands in the plantations allows access for spraying but is also beneficial for other wildlife. Blanket spraying should be avoided due to harmful effects on beneficial invertebrates.

Controlling willow beetles by planting resistant varieties and maximising natural predators could provide long-term solutions but require further research.

6.2 Introduction

Large numbers of invertebrates are known to be associated with willows (Saixspp.). Work by Kennedy and Southwood (1984) found that five native species of willow in Britain supported 450 phytophagus (herbivorous) insects and mites. In addition, many more predatory and parasitic invertebrates will be found on willow, existing upon these herbivorous species. As several native species of willow are used to develop commercial willow varieties and so have genetic similarities to them, it is likely that many of the invertebrate species associated with native willows will also be found within commercial short rotation coppice plantations (Sage and Tucker 1998).

Gair eta. (cited in Sage and Tucker 1998) found that cereal crops supported only 45 invertebrate species. Thus the placing of willow coppice on former arable land is likely to lead to a local increase in invertebrate biodiversity. This increase could have a positive effect on other forms of wildlife. For example, increased insect numbers in willow coppice may encourage a larger breeding bird population, attracted by the abundant food source for their young.

In this study, the invertebrate numbers and diversity within short rotation willow coppice were studied. The same twelve sites used for summer and winter bird surveys and butterfly monitoring were visited. The distribution of the invertebrate population within the coppice was also studied. Potential pest species and their distribution, both within and between sites were identified and related to possible management options.

131 6.3 Methods

Unlike the butterfly monitoring described in this report (section 5.0), only short rotation coppice plots were monitored without arable control plots. Due to the differences in crop structure between willow coppice and arable fields, it was considered that any sampling method used would not allow meaningful comparisons to be made

Previous studies have shown that major seasonal variations occur in the insect community (Sage & Tucker 1998), so sampling on each coppice plot was undertaken twice in each of the four years of the project: the first round in May/June during the first period of butterfly monitoring and the second round in July/August during the third period of butterfly monitoring. Nine samples were taken at each site, covering both the edge and centre of the plot. Four samples were taken on each of two random transect lines going into the coppice between rows of trees. Samples were taken at the edge of the crop and at 4m, 15m and 60m into the crop. The ninth sample was taken at the approximate centre of the plantation, though in the case of West Farm, where the coppice was split into a number of compartments by internal hedges, the approximate centre of a compartment was selected.

Each sample was taken by vigorously beating the coppice stems with a metal bar, dislodging invertebrates onto a beating tray (110 cm x 86 cm = 0.946 m2) positioned on the ground between rows of trees. Beating continued until no further invertebrates could be seen dropping into the tray. All visible invertebrates in the tray were collected and returned to the laboratory for storage in alcohol and later identification.

During the first year of the project, no samples from the coppices planted in 2000 could be taken during the first collection period as only three of the six sites had been planted (Oak Farm, South Cave and North Duffield), and the cuttings were still too small to be sampled. During the second collection period, samples were taken from these three sites, but not from the remaining three (Shire Oaks, Foggathorpe and Rowland Hall Farm) which again had either not yet been planted or were too small to sample. Invertebrate collections were undertaken at all coppice sites planted in 1999.

In 2001, the coppice at Rowland Hall was not sampled during the first collection; the crop had shown poor growth and areas of planting had died. Infill planting was taking place at the time of our visit. By August the trees had grown high enough to allow sampling to take place. Foot and Mouth biosecurity measures also prevented the sites at Foggathorpe (which was also replanted in 2001) and Shire Oaks from being visited.

132 6.3.1 Data analysis

The collected invertebrates were classified into general taxonomic orders. Although not insects, spiders were found in the coppice and so the class Arachnids was also included. The groups included in the analysis were:

Coleoptera Beetles Hemiptera True bugs Psocoptera Book lice Dermaptera Earwigs Hymenoptera Wasps, bees Lepidoptera Butterflies, moths Diptera True flies Ephemoptera Mayflies Thysanoptera Thrips Dipiura Two-tailed bristletails Collembola Springtails Orthoptera Grasshoppers, crickets Arachnida Spiders Other Arthropods Preliminary analysis of the invertebrates collected showed that the majority belonged to five orders: Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, Thysanoptera, plus the Arachnida. The other orders of invertebrates were only occasionally collected. Thus the analysis concentrated on these six groups. The data on numbers of species and individuals were logarithmically transformed and analysed using paired t-tests. For ease of reporting, the class Arachnida is referred to as an invertebrate order in the text.

The coppice planted in 2000 only had two complete collections made: in 2002 and 2003. For this reason, 1999 coppice and 2000 coppice were analysed separately. As major seasonal variations in invertebrate numbers were expected, samples collected from each round were also analysed separately.

Based on previous studies of short rotation willow coppice, Chrysome/id beetles may have the potential to occur in large enough numbers to cause economically significant yield loss (Sage and Tucker 1998). The Blue Willow Beetle Phyllodecta vulgatissima is a known pest species of willow and was found to be abundant amongst the sites monitored in this project. Further analysis focused on this species, its abundance in relation to other invertebrates present, distribution within the coppice and also distribution between sites. Sage and Tucker (1998) estimated that 10 or more adult beetles per m2 of crop in May or June would probably represent potential for crop damage. Their Abundance Index for willow beetles was applied to our study sites, in all rounds over the four years as an indicator of potential damage by willow beetle.

Willow Beetle Abundance Index (Sage and Tucker 1998): 0 - Species not present 1 - Species present but in low numbers 2 - More than 10 adults per m2.

133 6.4 Results

6.4.1 Order composition

Summary

The Coleoptera and Hemiptera orders contained the majority of invertebrates collected on coppice planted in both 1999 and 2000. Numbers of Coleoptera mostly increased significantly between the two collection rounds in both ages of coppice. Other orders of invertebrates showed no clear pattern of change in numbers either between rounds or years.

The abundance of the six invertebrate orders mentioned above (6.3.1 Data analysis) was used to identify differences in invertebrate composition between coppice planted in 1999 and 2000, but also between the two rounds of collections.

1999 coppice

Coleoptera and Hemiptera made up the majority of invertebrates found in all years and in both collection periods. In all four years, more Coleoptera were collected in the second round (July/August), and this increase in numbers was significant in 2000, 2001 and 2003 (Figure 6.1; Table 6.1).

Hemiptera numbers increased between rounds only in 2001, and this increase was significant. In the other three years of the project, numbers of Hemiptera declined between rounds, though this reduction was significant only in 2002.

Hymenoptera occurred in lower numbers than Coleoptera or Hemiptera in all four years, though numbers increased significantly between rounds. Lepidoptera, Thysanoptera and Arachnida all occurred at low numbers and showed a variable pattern of abundance both between rounds and years.

134 ■ Arachnida 3000 - □ Thysanoptera ■ Lepidoptera 2500 - ■ Hymenoptera □ Hemiptera 2000 - □ Coleoptera

1500 -

1000 -

500 -

Round 1 Round 2 Round 1 Round 2 Round 1 Round 2 Round 1 Round 2 2000 2001 2002 2003

Figure 6.1: Numbers of six invertebrate groups, collected from SRC planted in 1999.

■ Arachnida □ Thysanoptera 2000 - □ Lepidoptera □ Hymenoptera 0 Hemiptera -e 1500 - □ Coleoptera

1000 -

500 -

Round 1 Round 2 Round 1 Round 2 Round 1 Round 2 Round 1 Round 2 2001 2002 2003

Figure 6.2: Numbers of six invertebrate groups collected from SRC planted in 2000. Collections were made in two rounds in each of three years. (Data from 2001 covers only three sites).

135 2000 2001 2002 2003 t53 = -4.50 t53 = -7.80 t53 = -3.65 Coleoptera NS p = <0.01 p = <0.01 p = <0.01 t53 = -4.19 t53 = 2.53 Hemiptera NS NS p = <0.01 p = <0.01 t53 = -2.32 t53 = -6.65 t53 = -4.90 t53 = -1.65 Hymenoptera p = 0.01 p = <0.01 p = <0.01 p = 0.05 t53 = -4.76 Lepidoptera NS NS NS p = <0.01 t53 = -4.61 Thysanoptera NS - NS p = <0.01 t53 = -2.10 ts3 = -2.08 t53 = 1.98 Arachnida NS p = 0.02 p = 0.02 p = 0.03

Table 6.1: Differences in total numbers of the six invertebrate groups between the two rounds on 1999-planted coppice.

2000 coppice

Again Coleoptera and Hemiptera made up the majority of the invertebrates collected. Coleoptera numbers increased significantly between rounds in all three years. The other invertebrates showed no clear pattern of increase either between rounds or years (Figure 6.2; Table 6.2). Lepidoptera were only collected as caterpillars, and showed no significant differences in numbers between rounds in any year.

2001 2002 2003 t26 = -4.11 t44 = -2.31 t44 = -8.39 Coleoptera p = <0.01 p = 0.01 p = <0.01 t26 = -3.50 t44 = 1.89 Hemiptera NS p = <0.01 p = 0.03 t26 = -2.05 Hymenoptera NS NS p = 0.03 Lepidoptera NS NS NS t44 = -6.40 t44 = 2.26 Thysanoptera NS p = <0.01 p = 0.01 t44 = -2.15 Arachnida NS NS p = 0.02

Table 6.2: Differences in total numbers of the six invertebrate groups between the two rounds on 2000-planted coppice. (Only three sites included in 2001 and five sites in 2002 and 2003).

136 6.4.2 Order abundance and distribution in coppice planted in 1999

Summary

The mean number of invertebrate orders found in coppice planted in 1999 increased over the four years of the project. Maximum numbers were found at different distances into the coppice. The lowest number of orders were either at the edge or centre of the crop. No clear pattern of increase or decrease in number of invertebrate orders with distance into the coppice was apparent.

In 2000, the highest mean number of invertebrate orders was found 60m into the coppice in the first round and at 15m in the second round. The centre had the lowest mean number of orders in both rounds. There was a significant decrease in mean number between 60m and the centre in the first round only (t5 = 4.52, p = <0.01) (Figure 6.3).

During 2001, the highest mean numbers of orders were found 4m and 60m into the coppice in the first and second rounds respectively. Both the centre and the edge had the lowest mean number (3) in the first round but by the second, the centre had the lowest mean number of invertebrate orders. There was no significant difference in mean numbers between any distance points into the crop.

By 2002, the mean number of invertebrate orders had increased at all distances into the coppice and in both rounds compared to the previous two years. In the first round, the edge had the lowest mean number of orders, significantly lower than the number found at 4m (t5 = -2.31, p = 0.03). In the second round, the centre contained the lowest number of orders, which was significantly lower than found at 60m into the coppice (t5 = 3.69, p = <0.01).

In 2003, very little variation between mean numbers of invertebrate orders at different distances into the crop was found. The centre had the lowest mean number of orders in both rounds, while the highest were found at 60m and 4m in the first and second rounds respectively. There were no significant differences in mean numbers of orders either between rounds or with distance points into the coppice.

137 6.4.3 Order abundance and distribution in coppice planted in 2000

Summary

No clear pattern of changes in mean numbers of invertebrate orders with increasing distance into the coppice planted in 2000 was apparent. Higher numbers were generally recorded in the second rounds of collections. In all three years the centre had the lowest mean number of invertebrate orders in the first rounds; in the second rounds, distances varied. The highest mean number of orders varied from the edge to 60m in both rounds.

In 2001, mean numbers of invertebrate orders showed a pattern of distribution similar to that found in 2003 on the 1999 coppice. However, only three sites were monitored and there were large variations in numbers of invertebrate orders between sites. In the first round, the mean numbers of orders decreased towards the centre of the coppice. In the second round, mean numbers were similar from the edge to 15m into the crop. There were no significant increases or decreases in mean numbers of orders either between rounds or with distance into the crop (Figure 6.4).

In 2002, the centre had the lowest mean number of invertebrate orders in both rounds. Mean numbers of orders were similar along the transects into the coppice, with no significant differences between the different distance points.

138 a) 2000

■ First round □ Second round

centre

Significant increases between rounds: 4m (t5 = -4.31, p = <0.01); 15m (t5 = -6.71, p <0.01). b) 2001

centre Distance into crop c) 2002

centre Distance into crop

* Significant increase between rounds: edge (t5 = -2.31, p = 0.03) d) 2003

centre

Distance into crop

Figure 6.3: Mean number of invertebrates orders (+ 1 s.e.) found at different distances in from the crop edge on 1999-planted coppice in 2000-2003.

139 a) 2001 (three sites)

■ First round □ Second round

centre Distance into crop b) 2002 (five sites)

centre Distance into crop * Significant increase between rounds: 4m (t5 = -2.28, p = 0.04) c) 2003 (five sites)

centre Distance into crop

Figure 6.4: Mean number of invertebrate orders (+ 1 s.e) found at different distances in from the crop edge on 2000-planted coppice in 2001-2003.

140 The mean numbers of invertebrate orders in 2003 were higher than in 2002, with all distance points in both rounds recording higher numbers. The highest mean number of orders was found at 15m into the crop in the first round and at both 15m and 60m in the second. Lowest mean numbers were in the centre and at the edge in the first and second rounds respectively. In the first round, the mean numbers of orders decreased significantly between the 15m and 60m distance points ((t4 = 2.35, p = 0.04).

6.4.4 Changes in mean number of invertebrates with distance into crop (1999 coppice)

Summary

Invertebrate numbers generally increased between the first and second rounds, primarily due to a rise in the numbers of Coleoptera and Hemiptera. No significant distribution of invertebrates with increasing distance into the coppice was apparent in any of the four years, although the trend was for more at the edge. The centre tended to have the lowest of numbers in both rounds in most years. The numbers of invertebrates were highly variable between the six coppice sites.

In the first collection of 2000, the edge contained the highest mean number of invertebrates. Mean numbers decreased with distance away from the edge. The difference in mean numbers was only significant between 60m and the centre (t5 = 2.99, p = 0.02). By the second collection, the mean number of invertebrates had increased at all points into the coppice. The centre of the coppice still held the lowest mean number of invertebrates, and the greatest numbers were collected from 4m into the crop. There were no significant differences in mean numbers between distances into the crop, although the trend was for more at the edge and declining into the plot, particularly for the second visit surveys. (Figure 6.5).

In the first round of 2001, the highest mean number of invertebrates was recorded 60m into the crop, though numbers did vary between sites: Far shires had 189 invertebrates, the majority Coleoptera, at this point, whereas only one invertebrate, again a Coleopteran, was collected at Ellerker. The lowest numbers of invertebrates were collected 15m into the crop. Mean invertebrate numbers increased by the second round, primarily due to a rise in Coleoptera numbers. The highest mean numbers were recorded 4m into the crop, and the lowest in the centre of the crop.

141 a) 2000

■ First round ■c 30 □ Second round

centre Distance into crop b) 2001

centre Distance into crop c) 2002

2 200

o 100

centre Distance into crop

Significant increase: edge (t5 = -2.04, p = 0.05) d) 2003

2 250

2 200

% 100

centre Distance into crop

Figure 6.5: Mean number of invertebrates (+ 1 s.e) at different distances into coppice planted in 1999, in 2000-2003.

142 In 2002, the mean number of invertebrates increased at all the monitoring points into the crop, compared to the mean numbers collected in 2000 and 2001. In the first round of collections, most invertebrates were recorded 60m into the coppice. The edge, not the centre as in previous years, produced the lowest mean number. At all points, Coleoptera and Hemiptera were the dominant orders, but Hymenoptera and Thysanoptera occurred in greater numbers at 60m than elsewhere. By the second round, mean invertebrate numbers had increased at the edge and 4m into the crop. At the other beating points, mean numbers of invertebrates decreased, though differences were not significant. The centre of the crop contained the lowest number of invertebrates, a significant decrease from the numbers found at 60m (t5 = 3.31, p = 0.01).

The highest mean number of invertebrates was present 4m into the coppice in the first round of 2003. The centre had the lowest mean number. The only significant difference in mean numbers of invertebrates was between 60m and the centre (t5 = 2.42, p = 0.03). In the second round, none of the changes in invertebrate numbers were significant.

6.4.5 Changes in mean number of invertebrates with distance into crop (2000 coppice).

Summary

Only data from three years of the four-year project were analysed. Only three sites were included for 2001. Mean invertebrate numbers increased between the majority of first and second rounds. No clear distribution of invertebrates with increasing distance into the coppice was apparent over the three years. Once again, the tendency was towards more at the edge and declining towards the centre especially for the second round. However, only the last two years, 2002 and 2003, when five sites were monitored, were directly comparable. The centre had the lowest mean numbers in both rounds in all years. The numbers of invertebrates were highly variable between the coppice sites.

No analysis of the coppices planted in 2000 was undertaken in the first year of the project due to the low number of invertebrate collections resulting from the late planting of the trees.

In 2001 two rounds of invertebrate collections were only completed at three sites due to FMD. The distribution of mean invertebrate numbers showed a similar pattern to that shown in the 1999-planted coppice in the first year of its growth. The lowest mean number of invertebrates was recorded in the centre of the coppice in both rounds. In the first round, the highest mean number of invertebrates was found on the edge of the coppice, and in the second round, at 4m. Numbers increased between rounds at all collection points. These were not tested for significance due to the low number of sites monitored (Figure 6.6).

143 a) 2001 (three sites)

■ First round □ Second round

centre Distance into coppice b) 2002 (five sites)

56 100

centre Distance into crop c) 2003 (five sites)

56 160 g 140 ■c 120

centre Distance into crop

Figure 6.6: Mean number of invertebrates (+ 1 s.e.) at different distances into the crop on 2000-planted coppice in 2001-2003.

In 2002, two invertebrate collections were made at six sites. Foggathorpe has not been included in the analysis due to replanting in 2001. Again, the lowest mean number of invertebrates was found in the centre of the coppice in both the first and second rounds. Differences in mean number between 60m and the centre was only significant in the second round (t4 = 3.44, p = 0.01). The highest mean number was found 60m into the coppice in the first round and at 15m in the second round. Differences between rounds at each distance were not significant. Again, two collections were made at five sites during 2003. Mean numbers of invertebrates in both rounds and at all monitored distances into the crop reached

144 their highest levels of the three years. In both rounds the centre had the lowest mean number of invertebrates, and the differences in numbers from those found at 60m were also significant in both rounds (first round: t4 = 9.84, p = <0.01; second round: t4 = 2.36, p = 0.04). As in 2002, the 60m and 15m collection points had most invertebrates in the first and second rounds respectively. Differences in numbers between rounds were not significant.

6.4.6 Number of willow beetle in coppice

Summary

Willow beetle numbers increased over the four years of the project. Higher numbers were collected during the second rounds in both 1999-planted and 2000- planted coppice. In these second rounds, the majority of Coleoptera collected were willow beetle. As a percentage of total invertebrates, willow beetle decreased in the final year in 1999 coppice, whereas in the 2000 coppice, willow beetle continued to increase and make up over 60% of total invertebrates collected.

1999 coppice

Willow beetle numbers increased over the four years of the project. In all years, numbers of willow beetle were higher and made up a larger percentage of both total invertebrates and Coleoptera in the second round of invertebrate collections. As a percentage of total invertebrates, numbers reached a peak in both the first and second rounds in 2001 and decreased in 2002 and 2003. However, this reduction was due to an increase in the number of other invertebrates found and not a decrease in willow beetle numbers. Although Coleoptera increased over the four years, this was primarily due to the rising numbers of willow beetle (Table 6.3).

2000 2001 2002 2003 Round 1 2 1 2 1 2 1 2 Total willow 8 270 418 1491 879 1629 757 1674 beetles Total 244 598 637 1944 2248 2577 2562 3141 invertebrates % of 3.3 45.2 65.6 76.7 39.1 63.2 29.5 53.3 invertebrates Total 40 433 506 1690 1050 1741 915 1858 Coleoptera % of 20.0 62.4 82.6 88.2 83.7 93.6 82.7 90.1 Coleoptera

Table 6.3: Percentage of total invertebrates and Coleoptera made up of willow beetles in 1999-planted coppice

145 2000 coppice

No willow beetles were found in the three coppice sites visited in 2000. Over the remaining three years of the project willow beetle numbers rose. In 2001 and 2002, willow beetles made up a higher percentage of both total invertebrates and Coleoptera in the second rounds. In the second round in 2002 however, their percentage of total invertebrates dropped slightly, though actual numbers increased, indicating a rise in other invertebrate species found. In 2003, willow beetle numbers were almost four times higher in the first round than at the same time in 2002, and by the second round, numbers were almost 12 times higher. Although the increase in invertebrate numbers was partly due to new species being collected, the primary reason for this increase and the rise in Coleoptera numbers appears to be primarily due to the increase in willow beetle numbers (Table 6.4).

2000 2001 2002 2003 Round 1 2 1 2 1 2 1 2 Total willow 0 7 63 61 116 237 1322 beetles Total 57 102 278 440 1119 1617 2128 invertebrates % of 0 6.9 22.7 13.9 10.4 14.7 62.1 invertebrates Total 17 40 139 127 155 360 1451 Coleoptera % of 0 17.5 45.3 48.0 79.5 65.8 91.1 Coleoptera

Table 6.4: Percentage of total invertebrates and Coleoptera made up of willow beetles in 2000-planted coppice (2000 and 2001 covers only three sites. 2002 and 2003 covers five sites).

6.4.7 Distribution of willow beetle in the coppice planted in 1999

Summary

Willow beetle numbers showed a varied distribution in relation to distance into the 1999-planted coppice. Distances with the lowest mean numbers varied in the first rounds but in the second rounds the centre had the lowest mean number in three of the four years. The highest mean numbers in the first rounds were at 60m in three years, and at the edge, 4m and 60m in the second rounds. There was a wide variation in willow beetle numbers between the six coppice sites.

General patterns of colonisation of these crops support previous findings that show these beetles colonising edge zones in early spring feeding and laying eggs in these areas before moving further into the crop interior (Sage et ai, 1999). The high densities of beetles recorded in the edge zones in the second visit (July & August) would be second-generation beetles.

146 During the first round of collections in 2000, willow beetles were found only at three points in the coppice: the edge, 4m and 60m. Mean numbers had risen significantly at all distances into the crop by the second round, with a maximum at 4m. Lowest mean numbers were found at the centre (Figure 6.7).

More willow beetles were present at all monitoring points and in both rounds in 2001. The highest mean number was found at 60m into the coppice in the first round, and the lowest at 15m. By the second round mean willow beetle numbers had increased at all distances into the crop. The lowest mean numbers were in the centre of the coppice and the highest at 4m.

Willow beetle numbers showed a more variable distribution in 2002. In the first round the lowest mean number was found at the edge of the coppice, and the maximum mean number at 60m into the crop though this was not significantly higher than at 15m or the centre. The lowest mean number in the second round was at the centre and the highest at the edge.

In 2003, willow beetle distribution showed a more regular pattern than in 2002. In both rounds mean numbers increased up to 60m into the coppice. The lowest mean number was at the centre. The edge had the lowest mean number in the second round. There were no significant differences in mean numbers between rounds or between distance points into the coppice.

6.4.8 Distribution of willow beetle in the coppice planted in 2000

Summary

The centre of the 2000-planted coppice had the lowest mean number of willow beetles in the first rounds in the three years of monitoring. Lowest mean numbers in the second rounds were found at 15m in two years and the centre in the third year. Highest numbers in both rounds varied between the edge of the coppice and 60m. As in the 1999 coppice, there were wide variations in numbers of willow beetles between sites.

Mean numbers of willow beetles at the three sites monitored in 2001 were low, but all sites had beetles in both rounds. The lowest mean numbers were at 4m and 15m into the coppice in the first and second rounds respectively. Mean numbers at 4m showed a large increase between rounds but differences were not statistically tested due to the low number of sites monitored (Figure 6.8).

In the first round of collections in 2002, the centre had the lowest mean number of willow beetles, and 15m into the coppice, the highest. In the second round, the mean number of beetles declined at 15m into the coppice. The highest mean number of willow beetles in this round was at 60m which showed significantly more beetles than that found at 15m (t4 = -2.45, p = 0.04), but not than at the centre.

147 a) 2000

■ First round □ Second round

centre Distance into crop b) 2001

o 140 0 j§ 120 1 100 | 80

6 60 | 40 i» ^ 0 edge 4m 15m 60m centre Distance into crop * Significant increases: edge (t5 = -2.64, p = 0.02); 4m (t5 = -2.76, p = 0.02); 15m (t5 = - 3.51, p = <0.01) c) 2002

i 150

q3 100

centre Distance into crop * Significant increase: edge (t5 = -2.17, p = 0.04) d) 2003

0) 140 ■ First round I 120 □ Second round

centre Distance into crop

Figure 6.7: Mean number (+ 1 s.e.) of willow beetles collected at different distances into the crop on 1999-planted coppice in 2000-2003.

148 a) 2001 (three sites)

■ First round □ Second round

centre Distance into crop b) 2002 (five sites)

centre Distance into crop

c) 2003 (five sites)

w 160 140

= 100

^ 0 edge 4m 15m 60m centre Distance into crop

Significant increases: edge (t4 = -2.48, p = 0.03); 4m (t4 = -2.30, p = 0.04); 15m (t4 = - 2.67, p = 0.03); 60m (t4 = -3.08, p = 0.02) into the coppice).

Figure 6.8: Mean number (+ 1 s.e.) of willow beetles collected at different distances into the crop on 2000-planted coppice in 2001-2003.

In the last year of the project, the lowest mean number of willow beetles was found in the centre in both rounds. In the first round the highest mean number was at 4m into the coppice and numbers declined towards the centre. No significant differences in mean number at different distance points into the coppice were found. In the second round, the edge had the highest mean number, and numbers declined at each monitoring point towards the centre.

149 6.4.9 Abundance Index for Willow Beetles.

Summary

Overall, the numbers of sites with damaging levels of willow beetles increased over the four years. Coppices planted in 1999 had higher densities of willow beetle than those planted in 2000/2001, not only at the end of the project but also when all coppices were at the same growth stage, two years after planting. During the four years, five of the six 1999 sites had numbers of willow beetles likely to result in economically significant yield losses. Only at one coppice planted in 2000 had levels of willow beetle reached damaging levels by the end of the project.

Using the Abundance Index of Sage and Tucker (1998), five of the six sites had a density of willow beetles of over 10/m2 which may have resulted in economically significant yield loss. Work by Rushton (1999) found some evidence to suggest that plants could recover from early but not late defoliation, and that a reduction in biomass yield was consistently associated with defoliation occurring at both periods. On this basis the coppices at Far Shires suffered serious yield loss in 2001, Hawthorne House in 2003, Paddock House Farm in 2002, and Ellerker and West Farm in both 2002 and 2003. Very few willow beetles were collected at Charity Farm (Table 6.5).

Sites planted in 2000/2001 generally had willow beetle densities of less than 10/m2, a level unlikely to cause serious damage. Only at North Duffield, in the second round in 2003, did numbers increase to levels that result in economically significant yield loss.

150 2000 2001 2002 2003 Planting Round Round Round Round Round Round Round Round year 1 2 1 2 1 2 1 2 Far Shires 1999 1 1 2 2 2 1 2 1 Hawthorne 1999 0 1 1 2 1 1 2 2 House Paddock 1999 0 0 1 1 2 2 1 1 House Charity 1999 0 0 1 1 1 1 1 1 Farm Ellerker 1999 0 1 1 2 2 2 2 2

West Farm 1999 1 1 1 2 2 2 2 2

Shire Oaks 2000 - - - - 0 1 1 1 North 2000 - 0 1 1 1 1 1 2 Duffield South Cave 2000 - 0 1 1 1 1 1 1 Rowland 2000 - - - 1 0 0 0 0 Hall Oak Farm 2000 - 0 1 1 0 1 0 1

Foggathorpe 2000/2001 - - - - 1 1 1 1 Table 6.5: Assessment of the likelihood of sites to suffer crop damage, based upon the Willow Beetle Abundance Index (Sage and Tucker 1998)

0 - Species not present 1 - Species present but in low numbers 2 - More than 10 adults per m2.

6.5 Discussion

A total of 20122 invertebrates were collected and identified over the four years of the study, 7959 in the first round of collections (May/June) and 12163 in the second (July/August). These were classified into 15 orders (including Arachnida), of which 11 were found in the first rounds and 14 in the second rounds. The majority of invertebrates were Coleoptera, which was also found by Sage and Tucker (1998) in their study of 12 willow coppices. Hemiptera, especially aphids were also abundant. These invertebrates generally increased between the two collection rounds, as a result of reproduction as well as further immigration. Four other orders of invertebrates occurred in variable numbers but appeared to show no seasonal pattern of abundance. Invertebrates in the remaining eight orders occurred only occasionally and were collected only in low numbers or as individuals. Total numbers of invertebrates and number of orders increased over the four years, as the trees grew taller and the number of stems increased.

151 When the willow crop was short, either newly cut or planted, most invertebrate orders and higher numbers of invertebrates were found towards the outside edge of the coppice. This distribution is consistent with invertebrates colonising the coppice from surrounding habitats. During the second round of monitoring, invertebrate numbers were higher further into the crop, with peak numbers at 4-15m, indicating movement towards the centre of the coppice by invertebrates in search of further food supplies.

In subsequent years, the coppice centre generally continued to hold the lowest numbers of invertebrates, whilst peak numbers varied between the edge and 60m into the coppice. Overall, distribution of total invertebrates was variable both between years and also between 1999-planted coppice and 2000-planted coppice. In terms of invertebrate orders, there was little difference either in number or distribution between rounds or distance into the coppice in either age group. However, population and distribution trends are likely to have been confounded by the low number of sites and completed invertebrate collections within the 2000- planted coppice.

Willow beetles were present at all sites at some point over the four years of the project and made up a high proportion of both Coleoptera and total invertebrates. Numbers rose over the term of the study. Willow beetle numbers reached a maximum of 106/m2 on 1999 coppice at Hawthorne House Farm in 2003, and 76/m 2 on 2000 coppice at North Duffield in 2003. Using the willow beetle indicator that more than 10/m2 can result in economically significant levels of damage (Sage and Tucker 1998), five of the six coppices planted in 1999 suffered damage severe enough to potentially lead to loss of yield. Of the six coppices planted in 2000/2001, only one supported willow beetles above the critical level of 10/m2 by the end of the study.

Previous work (Sage et ai. 1999) demonstrated that after winter hibernation, willow beetles colonise the edge of a coppice early in the year and then move further into the crop later on. Although this pattern of distribution was apparent for total invertebrate numbers in the first year of growth after cutting and planting, it did not seem to occur for willow beetles. In 1999-planted coppice, three out of the four years (2001-2003) showed highest numbers at occurred at 60m into the crop in the first monitoring rounds. Only in the second rounds were numbers highest towards the edge, and then only in 2001 and 2002. However, the high densities of beetles recorded in the edge zone in the second round were probably second generation beetles, supporting general patterns of colonisation found in previous studies (Sage et al. 1999). Varied and atypical distributions may also have been the result of willow beetle control at some sites: Far Shires, West Farm, Hawthorne House Farm and Paddock House Farm, where the damage was most severe. The spraying of insecticides was timed to coincide with the movement of the willow beetles into the coppice in the spring, when the majority of beetles would be at the edge of the crop. Apart from killing the beetles before they reproduce, spraying at this time is a necessity due to the problems of access. Spraying machinery can only go around the outside of the coppice, using headlands and margins left during planting, and the insecticide reaches only the outermost lines of trees. Thus, spraying early in the

152 spring when the beetles are moving into the edges of the coppice maximises the effectiveness of the insecticides. This management practice could therefore have resulted in low numbers of beetles being collected at the edges of the coppice during the first rounds, but higher numbers further towards the centre, where those that had already moved into the crop were beyond the reach of any direct insecticide spraying or spray drift. In the second rounds, large increases in the numbers of willow beetles towards the edge of the coppice could be due to reproduction and the reverse movement of beetles from the interior of the coppice towards the outside in search of food.

At two sites, Far Shires and West Farm, the willow beetle problem became so severe that rows of trees were cut to allow easier access for spraying equipment. At West Farm, outer rows of trees were removed where original planting up to the surrounding fence had occurred, and at Far Shires, rides through the middle of the crop were created to allow spraying towards the centre of the coppice. In both cases, willow beetle numbers declined, though still remained high, but damage levels were greatly reduced.

Charity Farm was the only 1999-planted coppice site to have low numbers of willow beetle throughout the four years; a maximum of seven were collected in the second round in 2001. This could be due to the isolation of the site, away from other woodland, other willows, or even hedgerows. Rushton (1999) found that the flight dispersal of adult beetles from willows to overwintering sites was mainly confined to 100m. A lack of these overwintering sites and the large distance from any possible dispersion sites, probably contributed to keeping this site relatively free of willow beetles and thus damage.

All other 1999 coppice sites had hedgerows or woodlands along at least one boundary, and in the case of West Farm, the site was split into several compartments by internal hedgerows. These areas all provide overwintering habitats and sources of re-invasion by willow beetles the following year. At Hawthorne House Farm, it was noticeable that willow beetles overwintering in the adjacent hedgerows, led to severe defoliation of native Salix species in the hedgerows as well as in the coppice crop itself. However, willow beetle are known to use not only adjacent woodland and hedgerows for overwintering, but also adjacent buildings (G. Gaunt, pers comm.). This has occurred at Paddock House Farm and has become a problem for neighbouring residences to such an extent that grubbing up some of the coppice has been considered. Although all the coppices planted in 2000 also had hedgerows and woodlands along part of their boundaries, it is unknown why only one of these sites had a problem with willow beetles. North Duffield had a willow beetle density of 76.3/m2 in the last round of 2003, and severe defoliation was apparent. This site had hedgerows/mature trees along two boundaries, and a small area of woodland and reedbeds and scrub along the remaining two boundaries, all of which would have provided an ideal habitat for overwintering willow beetles and for re-invasion. It is possible that the other 2000 coppices with a willow beetle abundance index of '1' would develop damaging numbers of willow beetles (an index of '2') in the year following the end of the study.

153 As willow beetle are a recognised pest of willow coppice, various possible methods of control have been investigated in order to minimise crop damage and a yield loss. Some Salix species are known to have high concentrations of phenolic glucosides in their leaves, which deter willow beetles from feeding (Kendall et al. 1996). By planting a variety of willow species, some containing these high levels of repellent chemical, rather than monocultures of the same species, levels of damage may be reduced (Peacock and Herrick 2000, Peacock etal. 2001). The removal of plant debris and good weed control are recommended by Rushton (1999). However, tussocky grasses provide refuges for predatory spiders and beetles and certain flowering plants attract adult parasitoid wasps and flies (Sage and Tucker 1998), and their removal or management would not only affect these beneficial invertebrates but reduce the attractiveness of the habitat for other invertebrates such as butterflies. Planting coppices away from surrounding hedgerows and woodland would reduce the availability of overwintering sites for willow beetles (Rushton 1999), but would also turn the coppice into an 'island', slowing down colonisation by other species and reducing its biodiversity. Insecticide applications covering the whole of a coppice are uneconomic and reduce numbers of beneficial insects. Planning the coppice layout to incorporate headlands to allow access for spraying early in the spring when the willow beetles are colonising the crop, will prevent destruction of trees later on in order to gain access for machinery.

Our study showed that the planting of willow coppice on ex-arable land is likely to have increased invertebrate biodiversity when compared to cereal crops. Numbers of invertebrate orders and total numbers of invertebrates both increased over the four years, with Coleoptera and Hemiptera being the dominant orders present. However, our counts are underestimates of actual numbers present in the coppice sites, as no counts were made of invertebrates inhabiting ground flora either within the coppice or along the headlands. The increase in numbers and species not only increases biodiversity of the sites, but also acts as an important food source, encouraging colonisation of other wildlife. Willow beetle caused severe damage in several of he coppices, and although spraying along the coppice edges reduced numbers and damage, it probably also had an adverse effect on beneficial invertebrates. Coppice planting using mixtures of species with leaves containing repellent chemicals and the encouragement of predatory and parasitic invertebrates, may both provide long-term solutions, but require further research.

154 6.6 References

Kendall, D.A. and Wiltshire, C.W. (1998) Life-cycles and ecology of willow beetles on Salix viminaiis in England. European Journal of Forest Pathology, 28: 281-288.

Kendall, D.A., Hunter, T., Arnold, G.M., Liggitt, J., Morris, T. and Wiltshire, C.W. (1996) Susceptibility of willow clones (Salix spp.) to herbivory by Phyiiodecta vuigatissima (l.) and Galerucella Uneoia (Fab.) (Coleoptera, Chrysomelidae). Annals of Applied Biology, 129: 379-390.

Kennedy, C.E. and Southwood, T.R.E. (1984) The number of species of insects associated with British trees: a re-analysis. Journal of Animal Ecology, 53: 455-478.

Peacock, L. and Herrick, S. (2000) Responses of the willow beetle Phratora vuigatissima to genetically and spatially diverse Salix spp. plantations. Journal of Applied Ecology, 37: 821-831.

Peacock, L., Hunter, T., Turner, H. and Brain, P. (2001) Does host genotype diversity affect the distribution of insect and disease damage in willow cropping systems. Journal of Applied Ecology, 38:1070-1081.

Sage, R.B. (1998) Short rotation coppice for energy: towards ecological guidelines. Biomass and Bioenergy, 15(1): 39-47.

Sage, R.B. and Tucker, K. (1997) Invertebrates in the canopy of willow and poplar short rotation coppices. Aspects of Applied Biology, 49: 105-111.

Sage, R.B. and Tucker, K. (1998) integrated crop management of SRC plantations to maximise crop value, wildlife benefits and other added value opportunities. Report to ETSU. ETSU B/W2/00400/REP.

Sage, R.B., Fell, D., Tucker, K. and Sotherton, N.W. (1999) Post hibernation dispersal of three leaf-eating beetles (Coleoptera: Chrysomedidae) colonising cultivated willows and poplars. Agricultural and Forest Entomology, 1: 61-70.

Rushton, K (1999) Phenology and population dynamics of willow beetles (Coleoptera: Chrysomelidae) in short rotation coppicedwillows at Long Ashton. http://btgs1.ct.utwente.nl/eeci/archive/biobase/B10428.html

155 6.7 Appendix

Total number of invertebrates collected over the four-year project.

2000 2001 2002 2003 Total Round 1 2 1 2 1 2 1 2 Coleoptera 40 450 546 1895 1183 1971 1309 3414 10808 Hemiptera 182 101 68 185 1349 764 2331 1089 6069 Psocoptera 4 4 1 2 0 45 6 5 67 Dermaptera 0 0 0 2 1 7 1 2 13 Hymenoptera 9 23 31 154 42 143 58 66 526 Lepidoptera 1 36 27 25 38 29 37 55 248 Diptera 6 7 14 7 16 12 28 34 124 Ephemoptera 0 3 0 0 0 0 0 0 3 Thysanoptera 0 11 1 0 0 610 378 662 1662 Diplura 0 0 0 1 0 0 0 0 1 Collembola 0 0 24 0 12 11 7 1 55 Orthoptera 0 0 0 0 0 0 0 2 2 Arachnida 2 20 27 39 68 188 93 55 492 Arthropods 0 0 0 0 0 0 19 33 52 Total 244 655 739 2310 2709 3780 4267 5418 20122

156 7. ACKNOWLEDGEMENTS

In the first two years of the project Dr. Tracy Rich (Game Conservancy Trust) carried out bird survey work. Botanical field surveys were carried out by Lucy Bellini (as part of a postgraduate research project) in 2000 and by Nicola Clarke in 2001.

Peter Robertson (Central Science Laboratory) and Rufus Sage (Game Conservancy Trust) were initial supervisors for the project. The project continued to be supervised by Rufus Sage for the four-year period, alongside Niall Moore (CSL) for the first two years and Nigel Boatman (CSL) in the final two years.

George Watola, Pete Haynes, John Allcock, Dave Parrott, James Aegerter, Tim Drew and Niall Moore gave assistance with the butterfly monitoring. James Aegerter, Joshua Burnstone, Edward Jones, Jenny Mackay, Richard Smith, Nicola Dennis and Kate Rigney (all of CSL) helped with the invertebrate collection and identification.

The project was funded by the DTI through Future Energy Solutions. Staff at ARBRE Energy Ltd. supplied information on herbicides used on the sites and the variety mix used in the SRC plantations. Thanks also go to the SRC growers and landowners of arable control plots used in the study.

157