English Nature Research Reports

(Abbreviated)

Knepp Castle Estate Baseline Ecological Survey

Theresa E. Greenaway

Record Centre Survey Unit,

Sussex Biodiversity Record Centre,

 Woods Mill, Henfield,

West Sussex RH14 0UE

This is only part of the Record Centers Report. The whole document can be obtained from English Nature or from this web site in the near future (June 2006).

Preface

Using grazing animals as a management tool is widespread across the UK, but allowing a mixture of large herbivores to roam freely with minimal intervention and outside the constraints of livestock production systems in order to replicate a more natural, pre-industrial, ecosystem is not as commonplace.  The Knepp Castle Estate project provides the opportunity to study and evaluate habitat and biodiversity changes that may result in one area of southern England when a more natural grazing regime is implemented. 

Such changes cannot be assessed if there is no knowledge of the area of habitat types at the outset of a project and if there is similarly no knowledge of its flora and fauna.  This report presents a baseline study of the ecology of Knepp Castle and is as comprehensive as the available resources would permit. 

Summary

Following World War II, the Knepp Castle Estate was, in common with much of southern England, under increasingly intensive arable management.  The decision of its owner, Charlie Burrell, to return the Estate to a more natural environment has resulted in some 322 hectares being taken out of arable cultivation and instead grazed with a low number of cattle, pigs, ponies and deer.  Intervention is minimal within compliance with UK legislation. 

The interest in conservation grazing and near-natural grazing and the differences between these two systems is currently high, following Frans Vera’s book Grazing Ecology and Forest History and the debate that this publication has subsequently engendered.  However there are many as yet unanswered questions regarding how a near-natural system might operate in 21^st Century Europe, despite the seminal example of Oostvaardersplassen in the Netherlands.  By moving a considerable way towards near-natural grazing, the Knepp Castle Estate presents the chance to explore some of these issues. 

Baseline ecological information is a prerequisite to evaluating the short, medium and long term changes that more natural grazing might drive on the Knepp Estate.  Commissioned and voluntary fieldwork carried out in the summer of 2005 covered the following: 

• Habitat survey
• NVC and vascular plant survey of the River Adur corridor across Knepp
• Lichen survey
• Fixed point photography
• Wetland Mollusca
• Odonata
• Lepidoptera
• Wetland Coleoptera
• Ant survey
• Pitfall trap invertebrates
• Amphibian survey
• Reptile survey
• Breeding bird survey
• Barn owls
• Bat survey
• Water vole survey
• Water shrew survey
• Dormouse survey
• Other small mammals (shrews, voles, mice) survey

Each of these surveys is presented in this report, although for reasons of size, much of the raw data is not presented here.  As indicated throughout the report, this raw data and the digital photographs are available from the Record Centre Survey Unit.

The results of the surveys are discussed and future lines of research and surveillance are recommended.  Although an objective of this report is that the information contained in it should be used to guide future research, surveillance and monitoring, it is not within its remit to develop such a strategy here.  This study will provide a baseline against which any ecological changes resulting from a more natural grazing regime can be measured.

Acknowledgments

 1.     Introduction

1.1. The Knepp Castle Estate

1.2. Vision for Knepp Castle Estate

1.3.  Rationale and background

1.4.  Near-natural grazing at Knepp

1.5.  The aim of Knepp Castle Project

1.6.  Project management

References

Missing Section: Detailed Survey reports and Maps - sections 2 and 3. see individual survey reports in the directory. 

2.     Field survey work 2005

3.     Survey reports

4.     Discussion

4.1.  Review of objectives

4.2.  Survey evaluation and recommendation

4.3.  Monitoring strategy

4.4   Conclusions

Acknowledgements

Many people have contributed both to this report and to the Knepp Castle Estate project.  I would first like to thank all those who carried out fieldwork or specimen identification in 2005, sometimes in weather conditions that were less than ideal.  In alphabetical order, these are:- 

Professor Paul Buckland, Charlie Burrell, Mike Edwards, Mark Elliott, Dr Tim Freed, Peter Hodge, Rich Howorth, Paul James, Alexander Kent, Dr Gerald Legg,  Andy Phillips, Yohanna Regis, Dr Patrick Roper, Kate Ryland, Anne Sanders, Fran Southgate, Dr Jacqui Middleton, Antonio Uzal, Dr Barrie Watson, Daniel Whitby and Dr Martin Willing.

Thanks also to those who read through the report, in particular Henri Brocklebank, Charlie Burrell, Jason Emrich, Rich Howorth, Dr Keith Kirby and Dr Tony Whitbread. Dr Anita Diaz helped with the planning of some of the fieldwork and gave advice on statistical analysis. Cath Laing produced the maps, and Charles Roper was always there to unravel technical difficulties. 

Although already mentioned, particular thanks must be given to Charlie and Isabella Burrell, whose hospitality has been generous and without whom this project would not have been possible.  On behalf of Tim Freed, Anne Sanders and Antonio Uzal, I would like to express thanks and gratitude to Charlie and Isabella for kindly putting them up overnight. Jason Emrich provided invaluable assistance in ensuring the fieldwork could take place; and finally, thanks also to the staff in the Estate Office for their help.       

Knepp Castle Estate Baseline Ecological Survey

1  Introduction

1.1                          The Knepp Castle Estate

The Knepp Castle Estate lies to the south of Horsham, West Sussex (Fig.1.1).  Its long history has resulted in a number of features of archaeological, cultural and geological interest, including the remains of the original 11^th century castle. Knepp Castle Estate originated in the Middle Ages, when it was one of King John’s hunting parks.  It now extends to a total of 1,416 hectares (3,500 acres).  The original Estate seems to have been a hunting park throughout the mediaeval period, following which the land was used for iron working in the 16^th century.  Since this industry fell into decay, the Estate has been an area of farmland and woods (Knepp Castle Fact Sheet, 2005).  Following World War II, it was increasingly under intensive farming.  An unusual feature of the Estate is that its historic field system has largely been retained.  Many fields are 4 hectares (10 acres) or less, and are still bordered by hedgerows.          

      Fig. 1.1. Location of Knepp Castle Estate. 

The Estate lies within the Low Weald Natural Area (English Nature, 1997) and has a heavy clay soil.  It is traversed by the River Adur and some of its tributaries.  Kneppmill Pond is a hammer pond constructed for nearby iron workings prior to 1568.  It is, at the time of this Report in 2005, currently the subject of an Environmental Assessment prior to major dredging works that are essential to prevent further reduction in the area of open water caused by progressive siltation (Chris Blandford Associates, 2003).  There are two Sites of Nature Conservation Interest (SNCI) on the Estate - H18 Kneppmill Pond, the River Adur and Lancing Brook, Shipley; and H30 Horsham Common, Alder Copse, Coate’s Furzefield and Constable’s Furze, Southwater.  These were designated in 1992 by West Sussex County Council.  SNCIs are non-statutory designations.  

1.2   Vision for Knepp Castle Estate 

1.2.1        Development of the vision 

Charlie Burrell, the present owner, has had a life-long ambition to recreate the landscape designed by Humphry Repton.  This was probably laid out when the modern Knepp Castle was built by the architect John Nash in about1806 (Knepp Castle website, www.knepp.co.uk).  As steps were taken to achieve this restoration, the project grew and developed into a far more ambitious scheme to create a landscape-scale park in which a variety of large herbivores would roam freely.  As far as possible, these animals would be ‘de-domesticated’.  Near-natural grazing would be replicated with the animals utilising the land with as little human intervention as possible.  The intention is that this near-natural grazing system will ultimately include a large part of the Knepp Castle Estate. 

The River Restoration Centre, in conjunction with the Environment Agency and Defra, also proposes to‘re-wild’ part of the River Adur as it crosses the Estate.  This involves restoring the Adur floodplain to its natural function and the river itself as far as possible to its original course before it was subjected to canalisation. 

1.2.2    The first stages

Knepp Castle Park has ‘historic parkland’ status, and it has thus been possible to revert large areas from arable to parkland under Defra’s Countryside Stewardship Scheme (CSS), a reversion of historical relevance (Knepp Castle Fact Sheet, 2005).  Further historic and location details are available in the Register of Parks and Gardens of Special Historic Interest, 2000. 

The restoration of the deer park began in 2001, when some 202 hectares (500 acres) of this former park were taken out of arable and commercial grassland.  This land was deer fenced and internal boundary fences were removed (Knepp Castle Fact Sheet, 2005).  The ground was ‘sterilised’ by continual cultivation and spraying with herbicide, and subsequently planted with native grasses.  This seed mix comprised:-

 About 28 hectares (70 acres) sown with the above also included the following wild flower seed mix:-

Fallow deer were introduced from Petworth and Gunton Parks in February 2002, longhorn cattle in June 2003, followed by six Exmoor ponies in November 2003 and a stallion in 2005.  Roe deer were already present on the Estate and in the wider countryside, and special gates allow them freedom to roam.  There are probably about a dozen within the deer fence at any one time (Jason Emrich, Knepp Estate Manager, pers. comm.). 

In 2004, the deer park was extended by a further 106 hectares (261 acres).  About 35 hectares (86 acres) of this were already in CSS, and the remainder was entered into CSS at this time.  This brought the size of the deer park to over 283 hectares (700+ acres). The additional area of land entered into CSS in 2004 was treated differently.  Following the removal of wheat and rape, the seed beds were cultivated, sprayed with herbicide and drilled with the following mixture of stewardship grasses:- 

20%  Chewings fescue Festuca rubra ssp commutata, meadow fescue Festuca pratensis

15%  Smooth stalked meadow grass  Poa pratensis

10%  Crested dog’s tail Cynosurus cristatus, tall fescue Festuca  arundinacea, cocksfoot

Dactylis glomerata, common bent Agrostis  capillaris, small timothy Phleum   bertolinii, applied  at 20kg/ha.  

In addition, this land was broadcast with Essex broadleaf red clover at 0.5kg/ha, and a mixture of:

applied at 250g/ha (Knepp Castle Fact Sheet, 2005). 

In early January 2005, two Tamworth sows and their eight piglets were introduced.  This brought the stocking levels up to an estimate of around 550 animals for summer 2005 (Jason Emrich, pers. comm.) – about 500 deer, 6-10 ponies, 16 cattle with 13 calves and 10 sows. 

At the time this report was prepared (December 2005), a further area north of the A272 had also been entered into CSS and is currently undergoing ‘reversion’ to parkland. This brings the project area to approximately 322ha.   

1.3   Rational and background 

1.3.1  Landscape-scale ecology 

Much attention has traditionally been given to studies on the ecology and behaviour of individual species or small communities, typically on timescales of 3 years or less and spatial scales of 10m or less.  This may accord well with constraints integral to the timescale and funding of academic research but today, the pressing concerns of conservation biology are on longer time scales, and vastly greater spatial scales (May 1994). 

The ‘Single Large or Several Small’ debate has been going on since the 1970s and the limitations of both options were summarised by Rosenweig (1995).  The concept of ‘stewardship’ (Whitbread and Jenman, 1995) accords well with the management of small reserves.  However, doubts about the effectiveness of this strategy to conserve biodiversity, and the high economic cost of maintaining small areas of habitats and populations of species of high conservation concern, are resulting in increasing support for large-scale areas in which natural or near-natural processes drive biodiversity conservation.  Linking nature and planning on a landscape scale has numerous advantages over conservation in small fragmented reserves, and is now considered to be an essential approach in the conservation of biodiversity in Europe (Hodder & Bullock  2005).  

One of the drivers progressing landscape-scale conservation in Europe has been Natura 2000 which in turn derived from the Habitats Directive (Council Directive on the Conservation of Natural Habitats and Wild Fauna and Flora 92/43/EEC) and the Birds Directive (79/409/EEC).  This initiated a European network of protected nature areas.  In the Netherlands, the National Ecological Network comprises a spatially coherent network of existing and new nature areas that should be ready by 2018 (Anon, 2004).  In Britain, the concept of restoring near-natural ecosystems by near-natural processes was expounded by Whitbread and Jenman in 1995.  

1.3.2    Grazing as a driver for landscape scale ecological processes 

Frans Vera’s study of the effects of grazing on forest history (Vera 2000) has excited much interest, invoked much support, raised a number of issues and provoked considerable discussion if not dissent - all of which have served to enliven and enrich ecological theory and, it is to be hoped, practice.  This report is not the place to engage upon an evaluation of Vera’s lengthy dissertation, but quoting the null and alternative hypotheses may be useful: 

      Null hypothesis: “That pedunculate and sessile oak and hazel survive in a closed forest and regenerate in gaps in the canopy in accordance with Watt’s gap phase model (1947) and Leibundgut’s cyclical model (1959, 1978).  Large herbivores present in the natural state are dependent on the developments of the vegetation. According to this hypothesis, they do not have an influence on the course of the succession and regeneration of forests.” 

      Alternative hypothesis: “That the natural vegetation consists of a mosaic of large and small grasslands, scrub, solitary trees and trees growing in groups (groves), in which the indigenous fauna of large herbivores is essential for the regeneration of species of trees and shrubs which are characteristic in Europe.  According to this hypothesis, wood-pasture should be seen as the closest modern analogy of this landscape.” 

Vera’s thesis itself was based largely on a literature search.  English Nature’s interest in Vera’s theories resulted in an initial evaluation of his seminal work (Kirby, 2003) followed by a further report by Hodder and others (2005), which concluded that the case for Vera’s alternative hypothesis was not proven.  Apart from the historical validity (or not) of this hypothesis, there is considerable interest in the use of grazing as a way of generating diverse modern landscapes, inspired to some extent by the Dutch Oostvaardersplassen reserve. 

Oostvaardersplassen is one component of the Dutch ecological network.  Derived from reclaimed polderland in 1968, it is now a 5,600ha nature reserve (Whitbread & Jenman 1995) that has become one of the most influential examples of management by the implementation of near-natural processes.  The role of free-ranging herbivores in this system has inspired a huge amount of interest, influencing theoretical ecology as well as practical conservation.  However Oostvaardersplassen is unlikely to have any direct analogue in the UK.  It started from a low-biodiversity baseline of reclaimed land, inheriting no protected species or priority habitats. The grazing can truly be said to be ‘near-natural’ grazing rather than ‘conservation grazing’.  By contrast, in the UK, conservation grazing has tended to be implemented to maintain specific open landscapes or historical pasture woodlands.  

It might be useful at this point to summarise what is meant by ‘naturalistic’ or ‘near-natural’ grazing and ‘extensive’ or ‘conservation’ grazing.  These terms do not have formal definitions but depend on compliance or otherwise with the adherence to natural processes, and the following summary is based on Hodder & Bullock (2005). Thus in naturalistic grazing, there would be no specified grazing density, the grazing animals would be the key ecosystem drivers and natural processes would be allowed to proceed.  Herbivore populations would be limited by resources, fluctuating according to the amount of food available, the vicissitudes of climate and the impacts of parasites and pathogens.  The natural process would be seen as an aim in itself.  By contrast, the practice of extensive or conservation grazing systems acts as intervention that is aimed at achieving targets for habitat and species composition.  

In practice, grazing regimes such as that currently in place at Knepp lie somewhere between these two ends of the scale. The main reason for this is that although large in the context of lowland England reserves, the Knepp Estate is still too small to allow ‘natural’ population fluctuation, especially in the absence of large predators. The term ‘more natural’, despite its lack of definition, is therefore used in this report, indicating the intention to allow grazing that is as naturalistic as possible within certain constraints.  

1.3.3   The need for more research 

Although giving a stimulating incentive to ecological theory, relating Vera’s theory to biodiversity conservation is fraught with complexity.  Kirby (2003) cites Olff and others (2002), who question whether releasing free-ranging large grazers in former agricultural areas will really counteract the ongoing loss of biodiversity, as it is intensive agricultural practices themselves that have contributed to this loss.  Putting a number of large grazers onto arable reversion land thus feeds into the Vera cycle on a far more impoverished level than would have been the case in pre-industrialised Europe.  Rewilding including the restoration of ‘naturalistic’ grazing may be the optimal conservation strategy for the maintenance and restoration of biodiversity in Europe (Vera 2000), but in the short term, it may be unrealistic to expect much increase in biodiversity, certainly as far as the less mobile species are concerned. 

The impacts of a given cattle grazing regime on a particular woodland cannot yet be predicted, and Armstrong and others (2003) collated information from cattle-grazed woodlands across the UK.  Although focussing on conservation grazing by one kind of herbivore (cattle), this study nevertheless gives a large amount of information gleaned from visited and unvisited grazed woodland sites.  Much of this information is subjective and the authors observe that at many sites some form of quantitative monitoring was undertaken but results seldom analysed or written up.  

The primary objectives for grazing sites may be very different – for example, wilderness creation, biodiversity conservation or enhancement or to maintain an open habitat such as heathland or wood pasture.  In Holland as well as in the UK, grazing has been used as a conservation tool, particularly on open biotopes such as grasslands and heath (Ausden and Treweek 1995; Kuiters 2002; Symes & Day 2003), and increasingly, grazing in woodlands is being considered (Armstrong and others 2003).  Extracting rigorous scientific information from these, or monitoring the effects of grazing is hampered both because there has been no inventory of the site prior to the introduction of grazing and also because other management measures are implemented at the same time (Kuiters 2002; Sutherland 1995).  Kuiters also comments that there has been little research on the effects of grazing on the underlying processes of soil microclimate, and the resultant knock-on effects on seed germination, seedling recruitment, invertebrates and reptiles.  Studies are often limited spatially and temporally, and their results may appear contradictory. Further knowledge is needed on the underlying mechanisms driving habitat dynamics and diversity both with and in the absence of grazing, and this is relevant to all sites at all scales.  Grazing-related issues identified by Kuiters (2002) as needing further research can be summarised as follows: 

·        Research into underlying processes influenced or affected by grazing.

·        Evaluation of effects of grazing on flora, in relation to soil type, topography and other factors.

·        Research on effects of grazing on fauna.

·        Further exploration of Vera’s work

·        Role of thorny scrub in woodland regeneration in relation to soil type.

·        Grazing density and timing. 

1.3.4   Other Issues 

Apart from the issues raised above, near-natural grazing brings with it a number of other issues that need to be addressed.  Many of these have been identified, and continue to be appraised, in the Oostvaardersplassen project (Van Leewen and others 2003). 

·        Animal health – risk to farm livestock from spread of diseases such as foot-and-mouth disease.

·        Human health – transference of diseases such as anthrax to humans.

·        Animal welfare – issues include loss of condition in winter, supplementary feeding that reduces the ‘near-natural’ ethic; dealing with ill, injured or very old animals; use of preventative treatments such as antihelminthetics.

·        Control of animal numbers - lack of predators means less fit animals are not weeded out of the system naturally. Stock may suffer progressive loss of condition and health unless they are ‘artificially’ culled.

·        Herbivore corpses - by law these have to be removed.

·        Public acceptance – people often reluctant to embrace changes in what they perceive as their ‘natural’ surroundings.

·        Potential danger to humans – some breeds are more aggressive, or more aggressive at particular times of year, than others. 

Reconciling the needs of a near-natural grazing regime with these issues is likely to be difficult. Should the aim be for a consistent number year after year, or should an attempt be made to replicate ‘boom and bust’ cycles that may have existed naturally? Hard winters, parasite load, predators and summer drought would all have taken their toll in a natural situation, though seasonal migration would have helped to mitigate the adverse impacts of these. Overmars et al. (2003) discuss social structure and heredity in natural grazing.   However the more intervention there is with regard to animal numbers and so on, the less the system can be regarded as near-natural. 

Koene (2003) explores what is meant by ‘de-domestication’.  This is an important issue. Humans like the idea of ‘natural’ herds of large herbivores but we do not want them to kill us.  In the original plans for park restoration, Charlie Burrell rejected red deer introduction because of the danger they might pose to his children.  So it is essential in order to gain and maintain public support to differentiate ‘wild’ in the sense of ‘untamed’ but not ‘wild’ in the sense of ‘savage’.   Koene asks whether we want the animals to adapt to their natural surroundings or do we want to adapt the surroundings to the animals?  

Charlie Burrell also has other factors to take into consideration.  Running a large estate requires a large income and involves numerous liabilities such as inheritance tax, which are a drain on resources both now and in the future.  With these in mind, as well as the drive to reinstate near-natural grazing, the Estate also needs other income-raising ventures.  Some of these, such as the possibility of developing a natural environment tourist experience, are compatible with more exclusively ecological interests.  Other activities such as polo, deer stalking and pheasant shooting, although all traditional rural pursuits, do not have quite the same compatibility.  Programmes for ecological research and monitoring long-term ecological changes should take these other functions of the Estate into account.

 1.4   Near-natural grazing at Knepp 

The area at Knepp currently under restoration stands at about 322ha, which is just under a quarter of the entire Estate. It is projected that the area under near-natural grazing will increase, and an additional 1,000ha (approximate) may have potential for inclusion. However, although the area considered for the baseline survey work is already far larger than each of the largest three Sussex Wildlife Trust reserves (Malling Downs 215.5ha, The Mens 159.4ha and Ebernoe / Butcherlands 158ha), it is still comparatively small.  Even if the entire Estate were put under a more natural grazing regime, the area involved would only be a quarter of the size of Oostvaardersplassen.  Nevertheless, this site provides an opportunity for exploring more naturalistic grazing in the short, medium and long-term. 

Despite its small size relative to reserves in mainland Europe, Knepp has attracted keen interest from a number of experts, many of who have visited Knepp since the first moves to reinstate the mediaeval deer park. The opinions and advice of those such as Hans Kampf (Senior Policy Adviser, Ecosystem and the Environment), Frans Vera (Staatsbasbeheer / National Forest Service), Keith Kirby (English Nature), Tony Whitbread (Acting Chief Executive, Sussex Wildlife Trust), Paul Buckland (University of Bournemouth), Ted Green and Jill Butler (Veteran Tree Initiative), Julian Smith (landowner) and others have all helped to shape the direction in which the project has developed. 

The rationale outlined by Whitbread and Jenman (1995) has guided the development of much of Sussex Wildlife Trust’s recent conservation thinking and has resulted in a number of initiatives that are particularly complementary to the Knepp project. The major project that the Trust is leading is the West Weald Landscape Project, which is primarily funded by English Nature, the Heritage Lottery Fund, Sussex Wildlife Trust and the Environment Agency. This project is focused on a 23,820ha area at the western end of the Low Weald in the Surrey and West Sussex border area. It encompasses Ebernoe Common and The Mens, two SACs that are owned by Sussex Wildlife Trust. Chiddingfold Forest SSSI, in the north of the area, straddles the county boundaries and is owned and managed by Forest Enterprise. This project is focused promoting the integrated management of the landscape for the benefit of the people and wildlife that live there.  It is also working towards using more naturalistic grazing systems in some areas with the ultimate aim of reconnecting isolated landscape features to create an interconnected mosaic of dynamic habitats across core parts of the project area. 

The Ebernoe reserve now includes a series of old arable fields purchased from Butcherland Farm in 2001 with the help of the Heritage Lottery Fund. The aim of this acquisition is to enable the expansion of pasture woodland into the surrounding landscape, taking the pressure off Ebernoe Common SAC where a number of species with conflicting interests occur. The West Weald project is using this area to demonstrate how processes such as more natural, extensive grazing can be employed to restore this type of landscape.  Being able to carry out long-term surveillance on Ebernoe/Butcherlands and Knepp together to explore the effects that more natural grazing has on vegetation process and biodiversity will be of considerable scientific interest.  This work should contribute significantly to our understanding of the role that less rigidly structured grazing systems may play in 21^st century landscape management and conservation. 

The advantages of the Knepp Estate as a site to explore more extensive grazing may be summarised as follows:- 

·        with the exception of 2 SNCIs and a few COGS (County Geological Sites) and  English Heritage features, no part of Knepp Estate is designated SSSI, SAC or has other protected landscape status.

·        there are no rare or protected species for which conservation management measures have already been introduced on site.

·        it benefits from an owner who is extremely enthusiastic about and supportive of naturalistic grazing and re-wilding schemes .

·        the intention to introduce a more natural grazing regime is highly complementary to SWT’s West Weald Landscape Project and the restoration of the Butcherlands acquisition by natural processes.

·        the grazing project will run in tandem with the River Restoration Centre’s and the Environment Agency’s plans to restore and ‘re-wild’ the stretch of the River Adur that crosses the Estate.

·        Knepp Castle Estate presents an opportunity for exploring some of the issues raised in both landscape scale conservation and the issues of ‘re-wilding’ and ‘naturalistic grazing’ 

It is understood that the Estate is also hoping to qualify for grants under Defra’s new Higher Level Stewardship (HLS) scheme.  Biodiversity and habitat information obtained during this project will be used to produce a Farm Environment Plan in the event that the Estate applies for this.   

1.5   The Aim of Knepp Castle Project

1.5.1  The aim

The overall aim of the Knepp Castle near-natural grazing project is to record and evaluate changes in the biodiversity and vegetation structure following the reversion of land under intensive arable management to a more natural grazing regime.  The research emphasis will be the processes driving such changes and their effects at a landscape scale. 

It is very rare, especially in southeast England, to have the opportunity to evaluate ecological changes and issues on a site as large as Knepp.  This opportunity is immeasurably enhanced by the vision and active participation of its owner.  However, such good fortune brings with it certain difficulties.  With so much potential for research and survey, keeping this project running along the original brief (Appendix I) has not been straightforward, and indeed, as the baseline study progressed, it has been advantageous to modify and extend the brief.  

1.5.2  Objectives to achieve the aim

·        Preparation of a baseline biological inventory.

·        Development of a monitoring strategy, including the recording and evaluation of:

o       Changes in vegetation structure and communities

o       Changes to habitat pattern and distribution

o       Changes to vegetation species composition with time

o       Changes to habitat pattern across zones of likely change

o       Changes in the abundance and distribution of key plant species / groups with habitat change over time.

o       Changes in the abundance and distribution of key animal species / groups with habitat change over time.

o       The impacts, positive and negative, of near-natural grazing on the Estate over time.

·        Inform the River Adur restoration project and contribute to its subsequent evaluation.

·        Identification of appropriate areas of research. 

Actions taken:

·        Phase 1 Baseline report (Greenaway 2005)

·        Planning, commissioning and carrying out fieldwork during 2005 

Targets facilitated by 2005 baseline surveys:-

·        Interpretation of baseline information

·        Guidance of research initiatives

·        Planning of long-term monitoring strategy

·        Instigation of monitoring programme with appropriate resources

·        Evaluation of effects of near-natural grazing on existing biodiversity / landscape

·        Evaluation of effects on rare / protected species

·        Evaluation of effects on hedgerows

·        Evaluation of effects on woodland community and structure

·        Evaluation of scrub development

·        Evaluation of tree regeneration with relation to scrub development 

Although not part of the overall aim of this project, within these objectives there is considerable scope for additional studies including those involving single species or taxa and small-scale habitats.    

1.6    Project Management 

1.6.1  Organisation

The Record Centre Survey Unit was commissioned by Sussex Wildlife Trust and English Nature to carry out an initial desk study and scoping report (Greenaway 2005), followed by a baseline ecological survey.  The fieldwork commissioned as part of this baseline survey forms the main component of this report.  The maps presented in both the main report and the Appendix were prepared by Cath Laing, Sussex Biodiversity Record Centre, who digitised field data using GIS Arc View 8 software. Technical support was provided by Charles Roper, SxBRC. 

The scoping report (Greenaway, 2005) collated all existing biological information held on the Knepp Castle Estate.  This historical information was at best patchy and incomplete, although there were some good datasets.  In order to fulfil the aims of this project, it was considered that that a baseline ecological audit of the estate was essential if monitoring was to be meaningful and the effects of the proposed near-natural grazing were to be correctly assessed. 

The Knepp Castle Estate is large, and despite generous funding, there was simply not enough financial resource to cover all taxa.  Baseline audit requirement had thus to be strictly prioritised.  Parts of the Estate likely to provide the most useful ecological information were selected and a number of surveys were commissioned (Table 2.2.a) by the Survey Unit in spring 2005.  

Concurrently, Charlie Burrell invited Professor Paul Buckland (University of Bournemouth) to Knepp in order to discuss the project.  This resulted in the collaboration of the Estate, the University of Bournemouth and the Survey Unit in the organisation and management of additional field survey work.  In addition, the West Weald Landscape Project contributed 17.5 days of survey time. Other individuals have also volunteered their time and expertise. These contributors are also shown Table 2.2.a.  This additional participation has augmented the ecological audit considerably.  Each individual report is presented in Chapter 3. References are given at the end of each section except for Section 3, where they are placed at the end of each survey report. 

The Survey Unit feels immensely privileged to have been able to participate in the Knepp project.  With so much waiting to be explored, surveyed, assessed and evaluated, keeping the work within budget has been a difficult task that has required ruthless prioritisation.  Those who have been commissioned have worked far beyond what was strictly required in their short contracts.  Those who have given their time and expertise freely have made a most valuable contribution to the amount of information collected.  On behalf of the RCSU and SWT, I would like to thank everyone who has contributed to the work that has now been incorporated into this report.  I hope that all will feel that the time spent was worthwhile, and that all will be pleased to see the results of their own and other people’s endeavours. 

1.6.2 Funding

This project has been generously funded by Sussex Wildlife Trust, English Nature, Charlie Burrell and the Environment Agency.

References

ANON. 2004. Ecological Networks: Experiences in the Netherlands.  Working Paper, Ministry of Agriculture, Nature and Food Quality, The Netherlands. 

ARMSTRONG, H.M., POULSOM, L., CONOLLY, T. & PEACE, A. 2003. A Survey of Cattle-grazed woodlands in Britain. Woodland Ecology Branch & Statistics and Computing Branch, Forest Research, Northern Research Station. 

AUSDEN, M. & TREWEEK, J. 1995. Grasslands. In Managing Habitats for Conservation, Sutherland, W.J. & Hill, D.A. (eds). Cambridge University Press. 

CHRIS BLANDFORD ASSOCIATES. March 2003. Ecological Assessment of Knepp Mill Pond (Unpublished report) 

ENGLISH NATURE SUSSEX & SURREY TEAM. 1997. Low Weald and Pevensey Natural Area Natural Area Profile, English Nature. 

GREENAWAY, T.E. 2005. Naturalistic grazing on Knepp Castle Estate Phase I: Baseline Survey and scoping report. Record Centre Survey Unit, unpublished report. 

HODDER, K.H., BULLOCK, J.M., BUCKLAND, P.C. & KIRBY, K.J. 2005. Large herbivores in the wildwood and modern naturalistic grazing systems. English Nature Research Report No. 648. 

KIRBY, K.J. 2003. What might a British forest-landscape driven by large herbivores look like? English Nature Research Report 530. 

KNEPP CASTLE ESTATE. January 2005. Knepp Castle Fact Sheet (unpublished). 

KOENE, P. 2002. Ethology and large herbivores: what do we want? Vakblad Natuurbeheer. 

KUITERS, A.T. 2002. Hoofed animals in nature areas: theory and practice versus research. Vakblad Natuurbeheer. 

LEEUWEN, J.M.VAN & ESSEN, G.J.VAN. 2002. Health risks between large herbivores, farm animals and man.  Vakblad Natuurbeheer. 

LIEBUNDGUT, H. 1959. Über Zweck und Methodik der Struktur und Zuwachanalyse von Urwäldern. Schweizerische Zeitschrift für Forstwesen 110 : 111-124. 

MAY, R.M. 1994. The effects of spatial scale on ecological questions and answers. In Edwards, P.J., May, R.M. and Webb, N.R. (eds)  Large-scale Ecology and Conservation Biology, British Ecological Society , Blackwell Science. 

OLFF, H., VERA, F.W.M., BOKDAM, J., BAKKER, E.S., GLEICHMAN, J.M., MAEWYER, K. de & SMIT, R. 1999. Shifting mosaics in grazed woodlands driven by the alternation of plant facilitation and composition. Plant Biology 1 :127-137. 

OVERMARS, W., HELMER, W., MEISSNER, R. & KURSTJENS, G. 2002. Natural grazing, social structure and heredity. Vakblad Natuurbeheer. 

ROSENWEIG, M. L. 1995. Species diversity in space and time. Cambridge University Press. 

SUTHERLAND, W.J. 1995. Introduction and principles of ecological management. In W.J.Sutherland and D.A.Hill (eds) Managing habitats for conservation. Cambridge University Press. 

SYMES, N. & DAY, J. 2003. A practical guide to the restoration and management of Lowland Heathland. RSPB. 

VERA, F.W.M. 2000. Grazing Ecology and Forest History. CABI Publishing. 

WHITBREAD, A. and JENMAN, W. 1995. A natural method of conserving biodiversity in Britain. British Wildlife 6 No. 2: 84-93. 

WATT, A.S. 1947. Pattern and process in the plant community. Journal of Ecology 35: 1-22.

4.1. Review of objectives

It is apparent to anyone visiting the Estate that Knepp is made up of a variety of habitat mosaics within the broad categories of ‘woodland’, ‘grassland’ and ‘wetland’. The previous intensive arable management of the fields, and woodlands that were largely managed plantations, resulted in clearly defined boundaries between vegetation types. Allowing more natural processes is expected to result in the broadening of ecotones between different components of the habitat mosaic, as well as influencing shifts in the vegetation composition and structure in what are at present readily identifiable as fields and woods. 

The baseline field surveys have also indicated considerable biodiversity. Some of the Estate has now been out of intensive arable for some five years.  This is long enough for changes in plant species composition to become evident and for more mobile fauna to spread into the area under more natural grazing. Charlie Burrell and others living or working on the Estate feel that wildlife is already becoming much more evident (Knepp Castle website[1]). The scientific exploration of the dynamics of these changes is likely to prove instructive. 

The restoration of Repton’s historic park landscape and the implementation of low-level grazing across the Estate was not initiated to drive research, but it has provided a unique opportunity to study the effects of such grazing in the Low Weald of West Sussex.  The interest in near-natural grazing in relation to landscape scale ecology is currently strong, but there is relatively little published on its effects on biodiversity or vegetation structure.  Oostvaardersplassen is a source of inspiration, but this project started on reclaimed land, where the effects on existing biodiversity were not an issue. The need to consider biodiversity conservation at a landscape scale is paradoxically directly proportional to the increase in development in the UK, as the greater the pressure for development, the less effective is conservation in protected areas such as nature reserves likely to be.  Reserves may become islands providing no opportunities for dispersal, gene flow or climatic adaptation for many species of flora and fauna. The Knepp project has therefore attracted much interest and indeed support.  Charlie Burrell has been indefatigable in his efforts to enlist the participation of a wide range of experts and this has resulted in constructive and lively debate. 

The research aim of the Knepp Castle project is to record and evaluate changes in the biodiversity and vegetation structure that take place subsequent to the reversion of intensive arable to a system of more natural grazing. Objectives to achieve this aim, detailed in Section1.5, are firstly to improve the baseline biological information and secondly to monitor whether near-natural grazing causes changes to the habitats, flora and fauna in Knepp over time. 

Scientifically robust monitoring cannot be undertaken without an appropriate level of baseline biological information. Providing such information is the chief function of this report. The baseline surveys carried out in Summer 2005 will thus facilitate the development of the monitoring strategy necessary to achieve these objectives. 

4.2.  Survey evaluation and recommendations

Over 900 species have been recorded during the course of the 2005 fieldwork, including 71 species of conservation interest (Table 4.2.i).  These data will shortly be entered onto Sussex Biodiversity Record Centre database using Recorder 6. This is a fair total considering the 2005 fieldwork was limited by the available resources and until recently, the land was under intensive arable with all that such management entails.  

Table 4.2.i. Species of conservation interest recorded in 2005.

* unconfirmed - see text.

4.2.1. Vegetation survey 

Habitat survey.

The extended Phase 1 habitat survey together with detailed target notes is the key component of the baseline information, guiding the 2005 fieldwork that in turn will guide the monitoring strategy. The habitat classification followed, as far as possible, that used in Defra’s Higher Level Scheme.  This habitat survey gives a broad-brush overview that can be repeated at set intervals, and a ‘snapshot’ assessment of the Estate at the beginning of the near-natural grazing regime.  It shows that nearly 60% or the project area is grassland, some 21% is woodland including wood pasture / parkland and just 1.1% ismscrub.  As the more natural grazing takes effect, the amount of scrub (especially consisting of thorny and unpalatable species) might be expected to increase. 

Recommendations:

• Repeat habitat survey at regular intervals
• Monitor and evaluate scrub development
• Monitor and evaluate tree regeneration

Botanical survey of River Adur and Lancing Brook

This survey indicated a fair diversity of vascular plants that could be predicted to rise in the event of a spring survey. However, the abundance of duckweed, especially Lemna gibba, was evidence of eutrophication, and Rorippa amphibia was the only species of conservation interest (Table 4.2.i). Changes over time will be of great ecological interest. 

Recommendation:

• Repeat survey following river restoration

Transects

The data obtained from contiguous quadrats is essential for statistical analysis that will enable rigorous interpretation of the effects of near-natural grazing. The species recorded along these transects include those that were in the seed bank or that have colonised following reseeding as well as those that were in the seed mixes sown in 2001 and 2004. 

Recommendation:

·        It is suggested that recording along these transects should be repeated at regular intervals into the future, either at 1, 2 or 5-yearly intervals. Analysis of the results could be performed using Ellenberg’s indicator values for British Plants (Hill and others 1999), which is relatively quick and easy, but a more rigorous analysis would be to use a non-parametric statistical test such as Kruskal-Wallis or a multi-variate test such as Principal Components analysis, to test whether more natural grazing causes significant differences over time. 

4.2.2. Lichen Survey

Lichen surveys notoriously take a long time – a mature tree with a good epiphytic flora can take up to 2 hours to survey thoroughly. In the extremely limited survey that was undertaken, the 50 species recorded were largely the more common lichens that are typical of open woodlands in areas with reasonably good air quality. 

Recommendation:

• Further surveys to search for the less common species of both woodland and parkland.

4.2.3. Fixed-point photography

Fixed-point photography, although an inexpensive technique, does take a considerable length of time to carry out in an area as large as Knepp.  Managing an increasingly large library of digital pictures could also present problems.  Nevertheless, such images constitute an easily interpreted, qualitative method of monitoring vegetation change over time. The fixed-point photographs taken by Rich Howorth are augmented by others taken by Charlie Burrell, Theresa Greenaway, Kate Ryland and Fran Southgate.  Copies of these photographs are available from the Record Centre Survey Unit. 

Recommendations:

·        Address the practicality of compiling an increasingly large library of digital pictures

·        Agree a consensus of the suitability of this method over time

·        Explore other options such as satellite imaging.

4.2.5. Wetland molluscs

The River Adur and associated wetlands surveyed support small numbers of relatively common species.  This low mollusc diversity may well be the result of river canalisation and the recently abandoned intensive arable regime.  It is likely that run-off from arable practices caused some degree of eutrophication. This is indicated by the dominance of 5 species  (Lymnaea peregra, Physella acuta, Bithynia tentaculata, Sphaerium corneum and Pisidium nitidum), all of which are tolerant of slightly polluted or eutrophic waters.  Molluscs in general are unable to move rapidly and rely on events such as flooding to disperse them. It will be of great interest to monitor the effect that restoring a more natural river canal has on mollusc diversity. This mollusc survey is a good baseline against which to monitor this. Knepp Mill pond could hold important mollusc species, including freshwater mussels (M. Willing, pers. comm.), and a survey to confirm this would be advisable. 

Recommendations:

·        To repeat this survey following river restoration, and subsequently at regular intervals.

·        Carry out a freshwater mollusc survey of Knepp Mill pond. 

4.2.6. Dragonflies and damselflies

The desk study of existing records (Greenaway, 2005) indicated that the records of Odonata constituted one of the better datasets.  Twenty species of damselflies and dragonflies, including five species of conservation interest, have been recorded prior to the 2005 survey. In 2005, only fourteen were recorded, with just two species of conservation interest, hairy dragonfly and ruddy darter (Table 4.2.i). No species were recorded in 2005 that had not previously been recorded. If it had been possible to allow more time for this survey in 2005, further species may well have been seen. 

Recommendation:

·        To repeat this survey following river restoration, and subsequently at regular intervals. 

4.2.7. Moths

Any evaluation of the 2005 moth records must take account of the fact that this year was considered the worst for resident species in over 30 years. With a total of 63, predominantly grassland, species recorded on the reseeded grassland area, this habitat exhibits a fairly average total in comparison with neutral, unimproved grassland (Tim Freed, pers. comm.). Species diversity was higher in the sampling site in the River Adur floodplain, with 139 predominantly wetland species recorded. It will be of interest to observe any changes and rate of change, especially in the reseeded grassland area, over time. 

Recommendation:

·        Carry out a wider survey across the Estate in 2006, and use this as a definitive baseline against which to monitor changes. 

4.2.8. Butterflies

For unavoidable reasons, the butterfly survey started rather late in the season with the result that just 17 species were recorded, plus an additional species recorded by Dr Tim Freed. Two of these species, silver-washed fritillary and brown hairstreak are of conservation interest (Table 4.2.i). Previous to 2005, a total of 26 species has been noted. One species, marbled white, was a first record for Knepp. There is also an unconfirmed record of grizzled skipper.  The greatest diversity was observed in the Horsham Wood complex.  The present range of habitats already has the potential to support a rich diversity of butterflies. The abundance of most of the species recorded is currently low – with meadow browns and gatekeepers comprising two-thirds of the 900 or so individuals recorded. A good nectaring resource will be essential to maintain and increase many of the species present but in low numbers, and this depends on grazing pressure.  On a walk around Knepp in June during sunny weather, the number of butterflies present in a flowery strip between a boundary hedge and the deer fence was far higher than the numbers seen within the grazed area (Theresa Greenaway, pers. obs.). 

Recommendations:

·        The ideal would be to walk set transects every week during summer, in accordance with Butterfly Conservation methodology. Unfortunately, the time required for this means that few people are able to make the necessary commitment.

·        It may be more feasible to select one species of butterfly and monitor the effects of long-term near natural grazing on its population dynamics. 

4.2.9. Beetles

A total of 308 species of beetle has been recorded, including those from the river and its floodplain and those extracted from the pitfall traps. Although a considerable number, this can only be considered as a very incomplete record of beetles. The wetland beetle records do provide a fair baseline against which to monitor the effects of river restoration, but in order to use beetle diversity as a baseline against which to monitor the effects of near-natural grazing will involve further survey work.  Knepp Mill pond would also be expected to support a rich diversity of beetle species.  This would be of considerable relevance to dredging work, but is not strictly relevant to evaluating the effects of grazing. 

Recommendations:

·        To repeat the wetland beetle survey following river restoration and at regular intervals thereafter.

·        To carry out further survey work in 2006, extending the survey of grassland beetles across the Estate, and also surveying the woodlands, dead wood beetles and dung beetles. 

4.2.10. Ants

The ant survey, though limited, has considerable potential interest. They are in many ways ideal study material, as there are relatively few species (about 30 in southern England) and they are reasonably easy to locate.  Ants are social insects, many with specific habitat requirements, and winged queens are able to effect dispersal.  Results from Alex Kent’s work and the pitfall traps set up by Paul Buckland have identified eight ant species.  Most of these are common in southern England. The exceptions are Myrmica rubra, (a local species of damp sites) which was also recorded in Pitfall trap B2, Stenamma westwoodi, and Myrmica sulcinodis. Stenamma westwoodi has only been previously recorded twice in Sussex but this very underrecorded species (Pontin, 2005) may not be as rare as this lack of records implies.  It is likely that A. Kent’s record of Myrmica sulcinodis, an ant of wet heathland, should in fact be Myrmica scabrinodis, which was also identified from pitfall traps by Mike Edwards.   

Intensive arable management results in an absence of ants (Pontin, 2005).  Now that this has ceased over large area of Knepp, the rate of re-colonisation of ants and the dynamics of ant diversity over land now under near-natural grazing will be well worth studying.  Such research will make a considerable contribution to our understanding of the natural processes that are driven by large unmanaged herbivores.   

Recommendations:

·        Extend baseline survey of ants, and subsequently develop strategy to correlate ant diversity and population dynamics with grazing.

·        Monitor the rate of dispersal of meadow ant Lasius flavus into the reseeded areas by plotting the formation of anthills. 

4.2.11. Amphibians and pond condition

The  Knepp ponds are an important part of the overall habitat diversity of the Estate. As well as the number of amphibians that some support, many ponds are also likely to support diverse invertebrate communities.  Ponds also contribute to the attractive appearance of the landscape.  All the amphibians found on the Estate have protected status, with great crested newt enjoying particular protection.  This species was recorded by Buckingham in the 1990s (Buckingham, 1992), and again in 2005.  It is intended to survey those ponds not inspected in 2005 in May 2006.  It is not the function of this report to suggest management for particular species, however, ponds where great crested newts have been found should be noted and the implications of their protected status heeded.  It may be necessary to fence off such ponds and their immediate surroundings if grazing pressure becomes a threat. 

Recommendations:

·        Survey the outstanding ponds in May 2006

·        Supply information regarding the location of great crested newt ponds and responsibilities under the Wildlife & Countryside Act 1981 to the Estate.

·        Resurvey for amphibians at regular intervals into the future. 

4.2.12. Reptiles

All reptiles are also protected under the Wildlife and Countryside Act 1981.  Reptiles were not specifically surveyed for reasons outlined in S.3, but at least three species are known to occur on the Estate, all of which were seen in 2005.  At low levels of near-natural grazing, there is unlikely to be a significant adverse effect on reptiles.  Indeed, as the vegetation develops away from intensive arable to a more natural structure, reptile populations could be expected to increase, especially if there is suitable hibernation habitat. 

Recommendations:

·        Improve baseline information of reptile populations either by commissioned survey or student / volunteer involvement.

·        Supply the Estate with information regarding reptile hibernation habitat requirements. 

4.2.13. Birds

Sussex Ornithological Society undertakes a Wetland Bird survey every winter, and this information is available as necessary.  The breeding bird survey of 2005 was, as were other commissioned surveys, severely limited by the amount of funding available.  However, the results showed that the Estate supports a rich community of breeding birds, including 14 species of medium conservation concern (Amber List) and 8 of high conservation concern (Red List).  This is an encouraging start to the re-wilding project. Most of the Amber and Red list birds recorded could well increase as near-natural grazing progresses, although over-grazing could have a negative impact if scrub and hedge habitats decline and cease to be able to support those such as nightingales and yellowhammers. 

The maintenance of a favourable status for breeding birds is of paramount importance, as this will be a key factor in identifying any improvements in biodiversity as a result of the near-natural grazing regime. If bird population numbers or diversity fall, it will be a firm indicator that biodiversity as a whole is falling, as breeding birds require resources such as nest sites (scrub, hedgerows, trees, tussocky grassland etc) and food (invertebrates, seed, fruit etc). 

Recommendations:

·        Commission annual breeding bird surveys over a greater area of the Estate.

·        Start surveys earlier in the year to pick up early breeders.

·        Possibly focus particular research on species of conservation concern such as yellowhammer, nightingale and green woodpecker, all of which could potentially be affected either positively or negatively according to the level of grazing. 

4.2.14. Bats

The confirmation of 8 species of bats on the Estate was encouraging, given the fragmented nature of the woodlands. Good connectivity provided by the hedgerows does provide flightlines for commuting bats. The adult female bats recorded had all either given birth in 2005 or in previous years. This could indicate the presence of nursery roosts on the Estate, either in woodlands or buildings, depending on species.  The presence of female Bechstein’s bats was of particular interest, as this is one of the rarest bats in the UK. 

Recommendations:

·        Survey Great Cockshill Wood and adjacent woodland in May / June 2006 using radio-tracking to identify Bechstein’s bat nursery roosts

·        Provide information to the Estate regarding bats and tree work. 

4.2.15.  Water voles and water shrews

The presence of both these protected species has been confirmed. Further survey may well refine any population estimate obtained as a result of fieldwork 2005, but as far as the maintenance of these species on the Estate is concerned, ensuring that there is always as much suitable habitat as possible will be essential. This should develop naturally, although too high a level of grazing pressure may cause poaching. 

Recommendations:

·        Check watercourses for poaching, especially those known to have signs of water vole and water shrew.

·        Check all watercourses for signs of otter at least annually. 

4.2.16.  Other small mammals – shrews, voles, mice and dormice.

Shrews, bank and field voles, woodmice and yellow-necked mice are all expected to undergo population increases in the continued absence of arable cultivation. This in turn will provide an increase food resource for predators such as barn owls, stoats, weasels and foxes. The lack of firm evidence of dormice may or may not be an accurate reflection of the status of this rodent on the Estate and further survey work commenced earlier in the year will help to clarify this. There were no resources available to study rabbit numbers on the Estate. This would be useful information, as the effects of rabbit-grazing need to be considered. 

Recommendations:

·        Carry out more comprehensive dormouse survey.

·        Endeavour to prepare an estimate of rabbit numbers on the Estate.       

4.3.  Monitoring strategy

The results of the 2005 fieldwork should be used to inform and guide the planning of future research and the monitoring programme. However, the preparation of the monitoring programme is not within the remit of this report.  It is recommended that this report and the survey results obtained should be studied and that a forum should be convened to identify monitoring priorities and draft a monitoring strategy framework.  The success or otherwise of any such strategy will of course depend on adequate funding over what should be a long timescale. 

4.4.  Conclusions

Grazing as a conservation tool is not a new idea – especially on open habitats such as chalk grassland and heathland.  Few would dispute the essential role of sheep in maintaining the open, short sward of the Sussex Downs, but the benefits of grazing woodlands are less clear-cut, and there are many factors that have to be considered.  On Knepp there are large areas of grassland, the majority of which were formerly arable, and a number of relatively small areas of woodland.  Some of these woods are fenced to exclude animals, others are unfenced. It will be constructive to monitor the development of habitat mosaics across the woodland and grassland.

Near-natural grazing differs from what is generally meant by conservation grazing.  One of the most significant differences is the fate of the animals utilised – for instance, cattle employed in conservation grazing may still be part of a farmer’s beef production business, and as such will be removed from a site when forage is poor or supplied with supplementary feed.  Herbivores that are a part of a ‘de-domesticated’ near-natural grazing scheme are unlikely to contribute to meat supply for human consumption for a number of legislative reasons, and in order to fulfil their role would be left on site all year.  Any site can therefore sustain only the number of animals that can find sufficient food for survival in late winter (Helmer, 2002) or during summer drought.  If a fully near-natural system does develop on Knepp, this grazing regime will end up very different from the conservation grazing  utilised on some Sussex Wildlife Trust reserves.

There are very few published studies of the impact of cattle on woodlands (Armstrong et al., 2003) and virtually no published work, to date, of near-natural grazing in the UK. A special issue of Vakblad Natuurbeheer – ‘Grazing and Grazing Animals’, published in 2002, drew on the experiences of the first few years of the European National Ecological Network. This publication provides information on a range of issues and also identifies aspects about which little is known. Kirby (2003) examined Vera’s hypothesis, and in response to the relatively little quantitative spatial detail modelled a four-phase park-scrub-grove-breakup approach based on spatial and temporal patterning. He also drew attention to a number of issues pertinent to the UK that are not entirely compatible with Vera’s hypothesis. Hodder and others (2005) also consulted widely on a variety of issues raised by Vera, exploring his theory as well as discussing palaeoecological evidence and naturalistic grazing and conservation case studies. In spite of this, there are still no firm conclusions and certainly no complete agreement has been reached regarding either the past role of large herbivores in the European or UK wildwood or the relevance or advisability of any attempts to reproduce what is at best a hypothetical option.  What is certain is that more research is needed to address the questions raised both in the UK and on continental Europe. 

Trials of near-natural grazing are a crucial part of this research. We need to know more about the range of habitats and their dynamics that are likely to develop and also species of plants and animals that such habitats support. Only by evaluating such trials will our understanding of how a pre-human ‘natural’ landscape might have functioned be improved.  How relevant or useful this understanding may be to 21^st Century biodiversity conservation also remains to be seen, but it is to be hoped that the changes made to Knepp will at the very least have a part to play in maintaining the rich biodiversity of West Sussex. 

References

ARMSTRONG, H.M., POULSOM, L., CONNOLLY, T. & PEACE, A. 2003. A Survey of Cattle-grazed woodlands in Britain. Woodland Ecology Branch & Statistics and Computing Branch, Forest Research, Northern Research Station. 

BUCKINGHAM, D. 1992. Report on the amphibian and pond status of Knepp Castle Estate, 1991. Unpublished – a summary of BSc thesis held by Knepp Castle Estate. 

GREENAWAY, T.E. 2005. Naturalistic grazing on Knepp Castle Estate Phase I: Baseline Survey and scoping report. Record Centre Survey Unit, unpublished report. 

HELMER, W.  2002. Natural grazing versus seasonal grazing. Vakblad Natuurbeheer.

 Hill, M.O., MOUNTFORD, J.O., ROY, D.B. & BUNCE, R.G.H. 1999.  Ellenberg’s indicator values for British Plants. ECOFACT Volume 2, Technical Annex. Centre for Ecology and Hydrology & Natural Environment Research Council.

HODDER, K.H., BULLOCK, J.M., BUCKLAND, P.C. & KIRBY, K.J. 2005. Large herbivores in the wildwood and modern naturalistic grazing systems. English Nature Research Report No. 648.

KIRBY, K.J. 2003. What might a British forest-landscape driven by large herbivores look like? English Nature Research Report 530.

PONTIN, J. 2005. Ants of Surrey. Surrey Wildlife Trust.