Wildlife & Farming Conservation on lowland farms Ruth Feber & David Macdonald Wildlife & Farming Conservation on lowland farms Ruth Feber & David Macdonald Preface 2 Contents Habitats 5 Field margins 7 Hedgerows 15 Woodland & scrub 23 Citation Crops 31 This book should be cited as: Feber RE and Macdonald DW (2013) Wildlife & Farming: Conservation on Lowland Farms. Grasslands 39 Wildlife Conservation Research Unit, University of Oxford. Ponds 47 Published by Wildlife Conservation Research Unit, Ditches 55 Department of Zoology, University of Oxford, Rivers & streams 63 The Recanati-Kaplan Centre, Tubney House, Abingdon Road, Landscapes 71 Tubney, Abingdon, OX13 5QL. Wildlife 79 © Wildlife Conservation Research Unit 2013 Plants 81 All rights reserved. No part of this publication may be reproduced in any form or by means without the prior written permission of WildCRU. Butterflies & moths 89 The authors accept no liability whatsoever for any loss or damage arising from the Beneficial invertebrates 97 interpretation or use of the information, or reliance upon the views contained herein. Amphibians & reptiles 105 ISBN 0-9546376-6-6 Small mammals 113 Designed by Water voles & otters 121 www.tpcreative.co.uk Brown hare 129 Printed by www.techniqueprint.com Bats 135 Front cover © Ben Hall (rspb-images.com) Birds 143 Thank you 151 Wildlife and Farming 1 Preface This is a practical Handbook, providing advice to practical people. The question it answers is a crucial This Handbook is about delivering part of that vision: functioning one: how to conserve wildlife on farms, alive with wildlife, in a rich landscape that will engage and working farms in Britain. exhilarate the public who, ultimately, pay for it. Modern British farmers, and the agri- Science in general, and the WildCRU in particular, is collaborative. environment schemes that incentivise We are quick to acknowledge, and sincerely to thank, the many them, aspire to be custodians of a colleagues whose excellent work in diverse institutions underpin countryside that provides the nation the advice and information given here. Because we know our with food security alongside vibrant own work best, we use our own case studies as examples. Our wildlife and an inspiring landscape. farmland history began with large scale experimental studies of Farmers and policymakers want to field margin management at Wytham, near Oxford. Thereafter know what to do to fulfil this vision for our journey took us to field-scale experiments with set-aside, wildlife and farming. then farm system comparisons of conventional and organic © Julian Dowse/Natural England farms, then landscape systems in the Chichester Plain and, Over twenty-five years ago, the Wildlife Conservation Research most recently, the Upper Thames - lessons from all of these are Unit (part of the University of Oxford’s Department of Zoology) found herein. But some readers will want more detail, so we set out to help provide the answers. Our purpose was to work are publishing a companion volume ‘Wildlife Conservation on with farmers, not against them, to foster the sort of countryside Farmland’, which will synthesize the scientific evidence from our that society values. So, we began by seeking farmers’ opinions farmland studies over the last 25 years. and ideas for how better to integrate wildlife on farmland and to learn about their problems with wildlife. The down-to-earth We have worked closely with government and non-government approach reflects the WildCRU’s mission, which is to achieve organisations, amongst them the Wildlife Trusts, Defra, practical solutions to conservation problems through original Environment Agency and Natural England - we thank them, scientific research. The key word is evidence: the WildCRU’s acknowledge warmly their input, and hope that they and their role is to provide the scientific evidence that helps practitioners constituencies will find this Handbook useful. We are thrilled decide what to do. The evidence that supports the advice in this that the Handbook is endorsed by Natural England and we are Handbook has taken us 25 years to gather. indebted to the Rivers Trust, the Holly Hill Charitable Trust and Natural England for their generous support. This WildCRU Handbook is an idea whose time has come. In the last couple of years the nation has been formulating a new The Handbook is simple to use. There are nine chapters on vision for the environment. The Government’s Chief Scientific habitats and nine on wildlife groups. Each chapter follows the Advisor took the lead on reviewing food security. Natural England same format. Each briefly summarises up to date knowledge produced its audit of ‘Lost Life: England’s lost and threatened on each habitat/wildlife group, making key points leading to species’. September 2010 saw the publication of Professor Sir a management summary and a list of relevant Environmental John Lawton’s review, ‘Making Space for Nature’, with its catchy Stewardship options for each habitat/wildlife group, together advice of ‘better, bigger, more, joined’, ranking the priorities for with sources of more information. Each chapter has two feature improving management of protected areas, increasing their size, Boxes giving WildCRU research highlights. This is a ‘What to do’ creating new ones and joining them up. 2010 also saw publication book, and we are already at work on a companion volume on of the UK’s National Ecosystem Assessment and, in 2011,the ‘How to do it’. Natural Environment White Paper ‘The Natural Choice: securing the value of nature’, advocates moving towards a landscape- Ruth E. Feber and David W. Macdonald scale approach to conservation. The concept of paying for WildCRU, Oxford ecosystem services is beginning to be understood and applied. 2 Wildlife and Farming Wildlife and Farming 3 Habitats 4 Wildlife and Farming Wildlife and Farming 5 Oxeye daisies © Ruth Feber Field margins are among the most extensive and ubiquitous Field uncropped habitats on farmland and have the potential to provide habitat for a range of wildlife. Over-wintering sites for margins invertebrates, refuges for small mammals, nectar and pollen resources for pollinators, and nesting and feeding sites for birds can all be encouraged by establishing field margins. As well as being habitats in their own right, field margins protect other features, such as hedgerows or watercourses, from farm operations. They can also act as corridors, helping wildlife move through the landscape. Key points • Field margins or buffer strips will benefit a range of farm wildlife species • Different field margin options are possible, such as sowing with a tussocky grass mixture, including wildflowers to benefit nectar feeders, or cultivating margins for rare arable plants • Aim for a mosaic of patches of taller and shorter vegetation around the farm, cut infrequently once Overleaf image: view from Beacon Hill National Nature Reserve, Hampshire established and do not cut in summer. © Ruth Feber 6 Wildlife and Farming Wildlife and Farming 7 Field margins Field margins are the strips of land However, grass-only strips rapidly form dense swards and can between the field boundary (such as exclude naturally colonising wildflowers, often resulting in low a hedge) and the crop. Field margins species diversity. Including wildflowers (such as yarrow, black can be deliberately managed to knapweed and oxeye daisy) in the seed mixture will greatly benefit key farmland species and increase the value of margins for wildlife, providing a greater buffer strips are one of the most diversity of seed sources and host plants for invertebrate larvae, popular agri-environment scheme as well as pollen and nectar supplies for pollinators. Choosing options. species that flower and set seed at different times throughout the season will be even more beneficial. Field margins may contain a great diversity of plants, including those Naturally regenerated margins or buffer strips characteristic of woodland (hedge Field margins help buffer other features, such Field margins can also be established through natural bottoms), wetland (ditch banks), as ditches, from farming operations regeneration. If soil fertility is relatively low, and the soil seed grassland (grass margins) and arable © Rosalind Shaw bank and local flora relatively rich, these swards may have a (field corners and crop edges). Field higher conservation value than sown ones, making this method margins can be established around of establishment the most beneficial option. The decline of rare Female common blue butterfly© nutmeg66 CC BY NC ND 2.0 both arable and grass fields; in arable arable plants, such as the cornflower, can also be helped through areas they are especially valuable as they provide naturally regenerated buffer strips on light or shallow soils that undisturbed breeding and overwintering sites for are cultivated every one or two years. Varying the depth and wildlife. They act as buffers, protecting hedgerows, timing of cultivation can enhance plant diversity. ditches and streams from farming operations, and they form a network across the landscape, often Naturally regenerated margins can also provide important food linking bigger areas of wildlife habitat, such as resources for birds, both in summer and winter, in the form woodlands or wetlands. Naturally regenerated margins are the best of weed seeds and grain from volunteer crops and a range of conservation option on light or shallow soils invertebrates. The patchy sward may make it easier for birds to without grass weed problems find their prey. However, on very fertile soils, where the existing © Evelyn Simak CC BY SA 2.0 Establishing and managing field margins plant community is poor, or where there is a grass weed problem, © Emily Ledder/Natural England naturally regenerated strips may be difficult to manage, and sown Simple grass-only margins (above) provide breeding and Field margins can be established and managed grass and wildflower mixtures would be the better option. overwintering habitats, while the addition of wildflowers in several ways, described below, which will have (below) can greatly enhance their value to wildlife different consequences for the wildlife that use them.