Aquatic Plants in Britain and Ireland

365 Pages·2001·56.88 MB·English

by  Christopher D. Preston

AQUATIC PLANTS IN BRITAIN AND IRELAND

AQUATIC PLANTS IN BRITAIN
AND IRELAND
,
a joint project of the environment agency

institute of terrestrial ecology and the joint

nature conservation committee
by
C.D. PRESTON AND J.M. CROFT
illustrated by
G.M.S. EASY
LEIDEN • BOSTON
2014
This paperback was originally published by Harley Books (B.H. & A. Harley Ltd),
Colchester, UK, in hardback in 1997 under ISBN 0 946589 55 0 and in paperback in 2001 under
ISBN 0 946589 69 0, for the Environment Agency, the Institute of Terrestrial Ecology and the
Joint Nature Conservation Committee.
THE ENVIRONMENT AGENCY is a non-departmental public body whose responsibilities
largely cover the management and regulation of the water environment, including the conservation
of its flora and fauna; the control of certain industrial processes and the management of waste
disposal. The Agency’s responsibilities relate only to England and Wales.
THE INSTITUTE OF TERRESTRIAL ECOLOGY is a component of the Natural
Environment Research Council’s Centre for Ecology and Hydrology. The Institute develops
long-term multidisciplinary research to advance the science of terrestrial ecology. The securing,
expansion and dissemination of ecological data provide the basis for impartial advice on
environmental protection, conservation and the sustainable use of natural resources.
THE JOINT NATURE CONSERVATION COMMITTEE is the forum through which the
three country nature conservation agencies – the Countryside Council for Wales (CCW), English
Nature (EN) and Scottish Natural Heritage (SNH) – deliver their statutory responsibilities for
Great Britain as a whole and internationally. These responsibilities, known as the special functions,
contribute to sustaining and enriching biological diversity, enhancing geological features and
sustaining natural systems.
Designed by Geoff Green. Text set in Ehrhardt by Saxon Graphics Ltd, Derby.
Library of Congress Control Number: 2014940955
ISBN 978-90-04-27729-8 (paperback)
ISBN 978-90-04-27730-4 (e-book)
Text © NERC, JNCC and EA
Maps © NERC. Line drawings © G.M.S. Easy
This work is published by Koninklijke Brill NV. Koninklijke Brill NV incorporates the imprints
Brill, Brill Nijhoff, Global Oriental and Hotei Publishing.
Koninklijke Brill NV reserves the right to protect the publication against unauthorized use and
to authorize dissemination by means of offprints, legitimate photocopies, microform editions,
reprints, translations, and secondary information sources, such as abstracting and indexing services
including databases. Requests for commercial re-use, use of parts of the publication, and/or
translations must be addressed to Koninklijke Brill NV.
This book is printed on acid-free paper.
CONTENTS
Page
Foreword 7
Prefoce 9
Acknowledgements 11
INTRODUCTION
Definition of aquatic plants 13
Geographical coverage 14
Scientific and English names 14
SOURCES OF RECORDS
Criteria for incorporating new records 15
Major sources of records incorporated during the project 16
SYSTEMATIC ACCOUNTS
Explanatory notes on the text 19
Explanatory notes on the maps 20
Isoetaceae 21
Equisetaceae 26
Marsileaceae 31
Azollaceae 33
Nymphaeaceae 35
Cabombaceae 43
Ceratophyllaceae 45
Ranunculaceae 49
Polygonaceae 70
Elatinaceae 75
Brassicaceae 78
Primulaceae 88
Crassulaceae 90
Rosaceae 93
Haloragaceae 95
Lythraceae 103
Onagraceae 107
Apiaceae 110
Menyanthaceae 122
Boraginaceae 126
Hippuridaceae 128
Callitrichaceae 130
Plantaginaceae 139
Scrophulariaceae 142
6 CONTENTS
Lentibulariaceae 147
Campanulaceae 154
Butomaceae 156
Alismataceae 159
Hydrocharitaceae 176
Aponogetonaceae 195
Potamogetonaceae 197
Ruppiaceae 230
Najadaceae 233
Zannichelliaceae 238
Araceae 241
Lemnaceae 246
Eriocaulaceae 255
Juncaceae 258
Cyperaceae 260
Poaceae 298
Sparganiaceae 312
Typhaceae 322
Iridaceae 326
CONSERVATION DESIGNATION OF THE
RARER SPECIES
Rare and threatened plants in Britain 329
Scarce plants in Britain 330
Rare and threatened plants in Ireland 330
Protected species in Europe 330
British and Irish species with a restricted world distribution 331
List ofl ocalities cited in the text 332
Refrrenas 337
Index to accounts ofs pecies, subspecies and hybrids 362
FOREWORD
P
LANTS are an essential part of all healthy stretches of water from
the lochans high in the Cairngorms to the fenland drains near my
home in East Anglia. They provide a diversity of structure and form,
a nutrient recycling process, food sources and shelter for organisms of
very many kinds. At the same rime, some plants can cause problems
by physically obstructing water courses, by de-oxygenating water or
because they are poisonous to farm animals.
Sound knowledge of the status and distribution of freshwater
plants and an understanding of their biology are essential if man is to
live in harmony with nature - if our use of natural systems is to be at
all sustainable.
This volume presents, for the first time, a thorough review of all
freshwater plants in Britain and Ireland. It is both an atlas of distribu
tion and a compendium of scientific information. As such, it will help
to inform and improve decision-making for the management of our
rivers, streams and lakes. It also establishes a unique benchmark
against which future changes in the aquatic flora, and their wider
environmental implications, can be assessed. Consequently, it is a
fitting 'status report' for the end of this millenium.
I congratulate all those involved in the partnership that has pro
duced this important publication. I am delighted, at the dawn of the
new Environment Agency, to be able to commend this book to every
one with an interest or involvement in one of our greatest natural
assets-the freshwater environment.
May 1996 Lord De Ramsey
Chairman, Environment Agency

PREFACE
A
QUATIc plants have never been popular of Britain, Ireland and mainland Europe has
with the majority of botanists. Their aes been progressively modified by the direct or
thetic appeal is understated rather than blatant, indirect effect of human action, it has become
they grow in habitats which can be uncomfort increasingly important to recognize and protect
able or even physically difficult to examine, and those areas which still retain a 1ich aquatic flora.
some of the most important genera are taxo In this book we have attempted to summarize
nomically difficult. However, biologists who the distribution, habitat and reproductive bio
overcome these initial discouragements find logy of the aquatic plants of the British Isles,
that aquatic plants possess a number of particu and to provide a brief summary of their wider
larly interesting traits. Species from many dif distribution. Many terrestrial groups are rather
ferent families have become adapted to the · poorly represented in our area compared to
aquatic environment, and provide both remark mainland Europe, and they often reach
able examples of convergent evolution and maximum diversity in the high mountains of
striking illustrations of the fact that the same central Europe or the arid lands around the
biological problem can be solved in several dif Mediterranean. By contrast, the aquatic flora of
ferent ways. Reproduction by vegetative means the British Isles is relatively rich. We have (for
is often more significant than the normal modes example) 21 of the 22 European species of
of sexual reproduction, and sterile hybrids may Potamogeton and nine of the eleven species in
be ecologically important and very persistent. Ranunculus subgenus Batrachium. Our wet
Many species are effective colonists of remote climate, coupled with the effective dispersal of
or newly created habitats, and some have many aquatics, is probably responsible for this.
spread at a dramatic rate following their intro An account of our aquatic plants should, there
duction to areas outside their native range. fore, be of more than parochial interest.
These subjects have been treated in innumer In his book The Black Death, Ziegler (1969)
able research papers and in rwo boolm which confesses that 'no--one ... can be expert in this
have become classics: Arber's rVater Plants vast panorama and the spectacle of rival histor
(1920) and Sculthorpe's The Biology ofA quatic ians, each established in his fortress of
Vascular Plants (1967). specialised knowledge, waiting to destroy the
Since the publication of Sculthorpe's book, it unwary trespasser, is calculated to discourage
has become increasingly apparent that major even the most intrepid'. Although our field is
changes in the distribution of aquatic plants in more limited, we too have had to deal with
Europe have taken place in the last 50 years. many subjects about which we have no expert
Many species have declined in the face of habitat knowledge. We apologize for the errors and
destruction, unsympathetic management of omissions which we must inevitably have made,
existing habitats, or the acidification or eutrophi and hope that the value of the book ourweighs
cation of freshwaters. The long history of botan these faults. Above all, we hope that this work
ical recording in the British Isles allows us to will encourage many more botanists to study
document the effects of these changes. Other these fascinating plants.
species have been introduced and spread,
including several that originate in the New Monks Wood J. M. Croft
World. As the aquatic vegetation in many areas Apri/1996 C. D. Preston