Britain's Habitats: A Field Guide to the Wildlife Habitats of Great Britain and Ireland - Fully Revised and Updated Second Edition 9780691211794

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WILDGuides

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This book is dedicated to the memory of John Underhill-Day, friend, colleague and mentor for 20 years.

Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire OX20 1TR press.princeton.edu Requests for permission to reproduce material from this work should be sent to Permissions, Princeton University Press First published 2015 Second Edition 2020 Copyright © 2015 by Sophie Lake and Durwyn Liley, 2020 by Princeton University Press Copyright in the photographs remains with the individual photographers. All rights reserved.  No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the publishers. British Library Cataloging-in-Publication Data is available Library of Congress Control Number 2020943984 ISBN 978-0-691-20359-1 Ebook ISBN 978-0-691-21179-4 Production and design by WILDGuides Ltd., Old Basing, Hampshire UK. Printed in Italy

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CONTENTS Foreword ............................................................................................................................................................................................................................................................................... 6 Introduction ..................................................................................................................................................................................................................................................................... 8 Types of habitat ................................................................................................................................................................................................................................................. 11 Factors influencing habitats ............................................................................................................................................................................................................ 22 Natural change – Succession ......................................................................................................................................................................................................... 30 Habitat classification .................................................................................................................................................................................................................................. 33 Conservation of habitats ...................................................................................................................................................................................................................... 36

THE HABITATS ......................................................................................................................................................................................................................................... 39 WOODLANDS ....................................................................................................................................................................................................................................................... 40

Lowland Mixed Oak and Ash Wood ..................................................................................................................................................................................... 52 Lowland Dry Oak and Birch Wood .......................................................................................................................................................................................... 57 Beech Wood ........................................................................................................................................................................................................................................................... 60 Yew Wood .................................................................................................................................................................................................................................................................. 63 Wet Woodland .................................................................................................................................................................................................................................................... 66 Wood Pasture ....................................................................................................................................................................................................................................................... 72 Upland Oak Wood ......................................................................................................................................................................................................................................... 78 Upland Mixed Ash Wood ..................................................................................................................................................................................................................... 83 Caledonian Forest .......................................................................................................................................................................................................................................... 86 Atlantic Hazel Wood .................................................................................................................................................................................................................................... 91 Upland Birch Wood ...................................................................................................................................................................................................................................... 94 Coniferous Plantation ............................................................................................................................................................................................................................... 97

SCRUB ............................................................................................................................................................................................................................................................................ 100

Mixed Scrub ........................................................................................................................................................................................................................................................ 108 Hedgerow ............................................................................................................................................................................................................................................................. 111 Bracken ...................................................................................................................................................................................................................................................................... 117

HEATHLANDS .................................................................................................................................................................................................................................................. 120

Lowland Dry Heath .................................................................................................................................................................................................................................. 130   Some different types of Lowland Dry Heath ................................................................................................................................................ 135 Lowland Wet Heath ................................................................................................................................................................................................................................. 140 Upland Dry Heath ...................................................................................................................................................................................................................................... 143 Upland Wet Heath ..................................................................................................................................................................................................................................... 149

GRASSLANDS .................................................................................................................................................................................................................................................. 152

Lowland Calcareous Grassland ............................................................................................................................................................................................... 162 Lowland Dry Acid Grassland ....................................................................................................................................................................................................... 168 Lowland Meadow and Pasture ................................................................................................................................................................................................ 171 Purple Moor-grass and Rush Pasture .............................................................................................................................................................................. 174 Coastal and Floodplain Grazing Marsh ........................................................................................................................................................................ 177 Upland Calcareous Grassland ................................................................................................................................................................................................... 183 Northern Hay Meadow ....................................................................................................................................................................................................................... 186 Upland Rush Pasture .............................................................................................................................................................................................................................. 189 Upland Acid Grassland ........................................................................................................................................................................................................................ 192 Calaminarian Grassland ..................................................................................................................................................................................................................... 195

MOUNTAINS ...................................................................................................................................................................................................................................................... 198

Montane Dwarf-shrub Heath .................................................................................................................................................................................................... 204 High Montane Heath and Snow-bed ............................................................................................................................................................................. 208 Mountain Ledge ........................................................................................................................................................................................................................................... 212 Montane Scrub .............................................................................................................................................................................................................................................. 215

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ROCKY HABITATS ..................................................................................................................................................................................................................................... 218

Rocky Slopes ...................................................................................................................................................................................................................................................... 224 Scree .............................................................................................................................................................................................................................................................................. 227 Limestone Pavement ............................................................................................................................................................................................................................ 230

WETLANDS .......................................................................................................................................................................................................................................................... 234

Blanket Bog ......................................................................................................................................................................................................................................................... 244 Raised Bog ............................................................................................................................................................................................................................................................ 249 Upland Spring and Flush ................................................................................................................................................................................................................. 252 Lowland Fen ....................................................................................................................................................................................................................................................... 256 Valley Mire ............................................................................................................................................................................................................................................................. 260 Reedbed .................................................................................................................................................................................................................................................................. 265

FRESHWATERS .............................................................................................................................................................................................................................................. 270

Nutrient-rich (Eutrophic) Lake .................................................................................................................................................................................................. 282 Upland Lake, Loch and Tarn ......................................................................................................................................................................................................... 285 Peat-stained (Dystrophic) Waters ......................................................................................................................................................................................... 288 Turlough and Fluctuating Mere ............................................................................................................................................................................................. 291 Other types of Lake .................................................................................................................................................................................................................................. 294 Pond .............................................................................................................................................................................................................................................................................. 298 Ditch .............................................................................................................................................................................................................................................................................. 301 Canal ............................................................................................................................................................................................................................................................................. 304 Fast-flowing River and Stream ................................................................................................................................................................................................. 307 Sluggish River and Stream ............................................................................................................................................................................................................. 310 Chalk River and Stream ...................................................................................................................................................................................................................... 313

COASTAL HABITATS ............................................................................................................................................................................................................................ 316

Mudflat and Sandflat ............................................................................................................................................................................................................................. 326 Saltmarsh ............................................................................................................................................................................................................................................................... 329 Sand Dune ............................................................................................................................................................................................................................................................ 332 Machair ..................................................................................................................................................................................................................................................................... 338 Coastal Vegetated Shingle ............................................................................................................................................................................................................. 342 Saline Lagoon .................................................................................................................................................................................................................................................. 348 Rocky Shore ........................................................................................................................................................................................................................................................ 352 Soft Cliff .................................................................................................................................................................................................................................................................... 355 Hard Cliff and Cliff Slope ................................................................................................................................................................................................................... 358

OTHER HABITATS ..................................................................................................................................................................................................................................... 364

Arable .......................................................................................................................................................................................................................................................................... 368 Brownfield ............................................................................................................................................................................................................................................................ 372 Traditional Orchard .................................................................................................................................................................................................................................. 375 Garden ....................................................................................................................................................................................................................................................................... 378

Habitat Correspondence Tables ................................................................................................................................................................................................ 382 Species referred to in the text ...................................................................................................................................................................................................... 401 Photographic Credits ................................................................................................................................................................................................................................ 411 Map Credits .............................................................................................................................................................................................................................................................. 413 Acknowledgements .................................................................................................................................................................................................................................... 414 Index ................................................................................................................................................................................................................................................................................... 415

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The Broad Habitat Groups

Woodlands

Scrub

Heathlands

Grasslands

Mountains

Rocky Habitats

Wetlands

Freshwaters

Other Habitats

Coastal Habitats

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Foreword The variety of wildlife habitats in Britain and Ireland is truly astonishing. Ranging from dynamic coastal habitats to remote rocky mountains, from ancient woodlands and flower-rich grasslands to upland peat bogs and lowland heathlands, the list goes on and on – to the extent that there are now 65 different habitat types described in this second edition of WILDGuides’ excellent Britain’s Habitats. In these islands we have an astonishing record in terms of support for nature conservation –reflected, for example, in around 10% of the UK population being members of an environmental charity. Not only that, but we have protected species legislation and conservation programmes and national networks of protected sites with resources to support their management, which are the envy of the world. Despite this, each generation is experiencing an increasingly impoverished natural world, one where once-widespread plants, animals and fungi are now heading for extinction, and many habitats appear to be deteriorating inexorably. We are still going backwards on biodiversity, with the 2019 State of Nature report revealing that over the last 10 years, more species are decreasing (44%) in the UK than are increasing (36%). But it is not only species abundance that is of concern, because species distribution is also heading in the wrong direction, having fallen by 5% since 1970 for a suite of 6,554 terrestrial and freshwater indicator species. Despite the amazing efforts of so many people and organizations for the best part of a hundred years, it is clear that our traditional approach to nature conservation has not been sufficient to reverse the decline in biodiversity. Goodness knows where we would be without these efforts, but quite simply they have not been enough. We need something more besides – not instead of, but in addition – that enables dynamism to be restored and allows the development of functional natural systems. That something is rewilding – the largescale, long-term restoration of natural processes to the point where nature is allowed to take care of itself. Longhorn Cattle and Tamworth Pigs in mixed habitats at Knepp Wildland.

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A key principle of rewilding is to be non-prescriptive, especially with regard to species outcomes, but it is still important to embark on the rewilding journey with a good understanding of the habitats that are expected to develop both during the transition and in the longer term. As this book explains, very few of the habitats in Britain and Ireland are in fact near-natural – those that are, being confined to unstable cliffs, inaccessible ravines and ledges, and shifting foreshores, where natural processes are able to continue more or less unhindered. Most of our wildlife habitats are semi-natural, maintained in their current state through human intervention such as tree clearance or grazing. Patterns of land use that have continued in one form or another for thousands of years have created a cultural landscape in which human action has replicated the disturbance and flux that key species and natural processes would in many cases have created. Now, however, with human influence so predominant, the remains of this cultural landscape are no longer sufficient to support our precious wildlife. This superb book is a celebration of the habitats that we know and love – the jewels in the crown of our special sites. It shows us how rich and diverse our habitats can be. It also highlights how much of our landscape is taken up with intensive arable land, improved grassland or other degraded habitats. It provides an insight into the natural processes that shape habitats and how unfettering these could restore dynamism and connectivity in the landscape, helping to reverse the devastating wildlife losses we have presided over for too long. Britain’s Habitats provides us with a wealth of evidence, not only for countering the scourge of ‘shifting baseline syndrome’ in our attitudes to managing the countryside and urban green space, but also for making genuine strides in mitigating the impacts of climate change and reversing biodiversity decline. I commend it to anyone with an interest in our many and varied habitats, and in the future wellbeing of our natural environment. Prof Alastair Driver Rewilding Britain

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Introduction Habitats are the places where plants and animals live. They are characterized by distinctive combinations of plant and animal communities and their physical environment. This makes it possible to identify individual types of habitat, which is useful in understanding where different species are likely to be found and what their needs are – crucial information for protecting wildlife. Habitats are also valued in their own right as the diverse products of interactions between plants and animals and their environment. For this reason, nature conservation legislation affords protection to habitat types as well as to species. It is fairly easy to separate habitats into broad categories such as woodland, heathland, grassland, wetland and freshwater and many people are familiar with these terms. Yet within each of these categories there is a wide variety of different habitat types. These habitat types have been classified under a range of different systems (see page 35) that have been designed for a variety of purposes, and are in some cases very technical. This book provides a clear description of each of the wildlife habitats that are likely to be encountered in Britain and Ireland, enabling them to be recognized with confidence. For each habitat type, information is provided on its distribution and extent in Britain and Ireland, its ecology, origins and the way it has developed, and the conservation issues. These ‘habitat accounts’ also indicate the key features and species to look out for and the best times of year to visit. Although most habitats can be recognized quite readily, it is important to remember that they are variable – the habitat types described in this book are perhaps best considered as nodes on a continuum, with many variations and transitions. These transitions (sometimes called ‘ecotones’) may support species typical of both habitats as well as other species that are adapted to the transitional conditions – this can make them particularly rewarding to investigate. Sometimes habitats occur in easily distinguishable and often extensive patches with clear boundaries, but in other instances the transition is much more gradual and there is no distinct boundary. In some environments, or under particular management regimes, a variety of different habitat types and transitions between them can be found together in a distinctive combination which can, itself, be considered as a unique habitat. For example, Soft Cliff often contains a mosaic of grassland, wetland and scrub habitats, and Wood Pasture is a combination of woodland and grassland. Some habitats will not fit easily into any one of the accounts given in this book – they they might be transitional between different habitats, a fine-scale mosaic of habitats or a particular local expression of a habitat. For example, this site in Connemara supports a curious patchwork of Machair and Lowland Dry Heath.

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INTRODUCTION

above: Frenchman’s Creek, Helford River, Cornwall. Here the boundary between the different habitats

types (Mudflat and Woodland) is clearly defined. below: In this view of the Lake District several different habitat types can be seen, including 1 Scree, 2 Rocky Slope, 3 Upland Acid Grassland, 4 Bracken, 5 Mixed Scrub and 6 Upland Oak Wood. Individual habitat patches are straightforward to identify, but the edges are in some cases transitional, with one habitat type blending into another.

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INTRODUCTION

TYPES OF HABITAT

When trying to decide on a name for a habitat there is an impressive array of terms to choose from. Although some are broad and overarching (e.g. ‘freshwaters’), others are very precise (e.g. ‘Hard oligomesotrophic waters with benthic vegetation of Chara spp.’). The titles given to the habitat types included in this book err towards the more specific end of the spectrum as these are generally more informative. Full accounts are given for 65 main habitat types that fall within the broad habitat categories of woodlands, scrub, heathlands, grasslands, mountains, rocky habitats, wetlands, freshwaters, coastal habitats and ‘other habitats’, the latter being a catch-all for anything that did not fit comfortably elsewhere. Summary accounts are provided for a further nine rare habitats (five types of heathland and four types of freshwater lake). Although most of the habitats covered in this book are recognized as UK Priority Habitats (see Habitat Classification, page 35), even if their names may vary slightly, there are a few exceptions. This is either because, although not considered a priority for nature conservation, it is still a distinctive semi-natural habitat of some interest for wildlife (e.g. Upland Rush Pasture), or because it is in some way considered to be unique (e.g. Atlantic Hazel Wood). In order to provide a more logical classification from the point of view of identifying habitats in the field, some habitats have not been included within the same broad category that applies to UK Priority Habitats. For example, Calaminarian Grassland and Purple Moor-grass and Rush Pasture are within the grassland section of this book, although they are considered under ‘inland rock’ and ‘fen, marsh and swamp’ respectively as part of the UK Priority Habitat classification system. In addition, for ease of reference, most mountain habitats have been grouped together. The map opposite (together with the other habitat introduction maps) is derived from satellite imagery. The data are from the CORINE land cover, which is overseen by the European Environment Agency. The minimum size used in the map data is 25 ha, so parcels of habitat smaller than this are not recorded. The pie-chart summarises the data shown in the map.

Relative areas of the different broad habitat categories Rocky