Report Number 693 Knepp Castle Estate baseline ecological survey English Nature Research Reports working today for nature tomorrow English Nature Research Reports Number 693 Knepp Castle Estate baseline ecological survey Theresa E. Greenaway Record Centre Survey Unit Sussex Biodiversity Record Centre Woods Mill, Henfield West Sussex RH14 0UE You may reproduce as many additional copies of this report as you like for non-commercial purposes, provided such copies stipulate that copyright remains with English Nature, Northminster House, Peterborough PE1 1UA. However, if you wish to use all or part of this report for commercial purposes, including publishing, you will need to apply for a licence by contacting the Enquiry Service at the above address. Please note this report may also contain third party copyright material. ISSN 0967-876X © Copyright English Nature 2006 Cover note Project officer Dr Keith Kirby, Terrestrial Wildlife Team e-mail [email protected] Contractor(s) Theresa E. Greenaway Record Centre Survey Unit Sussex Biodiversity Record Centre Woods Mill, Henfield West Sussex RH14 0UE The views in this report are those of the author(s) and do not necessarily represent those of English Nature This report should be cited as: GREENAWAY, T.E. 2006. Knepp Castle Estate baseline ecological survey. English Nature Research Reports, No. 693. Preface Using grazing animals as a management tool is widespread across the UK. However 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. 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. 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 21st 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. Contents Preface Acknowledgements Summary 1 Introduction..................................................................................................................11 1.1 The Knepp Castle Estate..................................................................................11 1.2 Vision for Knepp Castle Estate........................................................................12 1.3 Rational and background.................................................................................14 1.4 Near-natural grazing at Knepp.........................................................................18 1.5 The aim of Knepp Castle project .....................................................................19 1.6 Project management.........................................................................................20 2 Field survey work 2005 ...............................................................................................22 2.1 Selection process - rationale ............................................................................22 2.2 People and organisations involved...................................................................22 3 Survey reports..............................................................................................................24 3.1 Vegetation and vascular plant surveys.............................................................24 3.2 Lichen survey...................................................................................................35 3.3 Vegetation survey of the River Adur floodplain..............................................36 3.4 Fixed-point photography..................................................................................41 3.5 Wetland mollusca.............................................................................................44 3.6 Odonata survey................................................................................................47 3.7 Lepidoptera – moths ........................................................................................49 3.8 Lepidoptera – butterflies..................................................................................55 3.9 Wetland Coleoptera.........................................................................................58 3.10 Ant survey........................................................................................................59 3.11 Pitfall trap invertebrates...................................................................................62 3.12 Amphibian survey............................................................................................67 3.13 Reptile survey ..................................................................................................68 3.14 Breeding bird survey........................................................................................69 3.15 Barn owls.........................................................................................................71 3.16 Bat survey........................................................................................................71 3.17 Water vole survey ............................................................................................74 3.18 Water shrew survey..........................................................................................76 3.19 Dormouse survey.............................................................................................77