Invasive plant ecology in natural and agricultural systems

221 Pages·2011·2.778 MB·English

by  Swanton, Clarence J., Murphy, Stephen D., Booth, Barbara Diane

Invasive Plant Ecology in Natural
and Agricultural Systems, 2nd Edition
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Invasive Plant Ecology in Natural
and Agricultural Systems,
2nd Edition
Barbara D. Booth
Independent Consultant, Guelph, Ontario, Canada
Stephen D. Murphy
Department of Environment and Resource Studies,
University of Waterloo, Waterloo, Ontario, Canada
and
Clarence J. Swanton
Department of Plant Agriculture,
University of Guelph, Guelph, Ontario, Canada
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permission of the copyright owners.
A catalogue record for this book is available from the British Library, London, UK.
Library of Congress Cataloging-in-Publication Data
Booth, Barbara D. (Barbara Diane), 1961-
Invasive plant ecology in natural and agricultural systems / Barbara D. Booth,
Stephen D. Murphy, and Clarence J. Swanton. -- 2nd ed.
p. cm. -- (Modular texts)
First edition published by CABI in 2003 with title: Weed ecology in natural and
agricultural systems.
Includes bibliographical references and index.
ISBN 978-1-84593-605-1 (alk. paper)
1. Invasive plants--Ecology. 2. Weeds--Ecology. I. Murphy, Stephen D. II.
Swanton, Clarence J. III. C.A.B. International. IV. Title. V. Series: Modular texts.
SB611.B59 2011
632'.5--dc22
2010009986
First edition published by CAB International in 2003. ISBN-13: 978 0 85199 528 1
ISBN-13: 978 1 84593 605 1
Commissioning editor: Rachel Cutts
Production editor: Fiona Chippendale
Typeset by SPi, Pondicherry, India.
Printed and bound in the UK by Cambridge University Press, Cambridge.
Contents
Preface vi
1 Introduction to Invasion Ecology 1
2 The Distribution and Abundance of Populations 8
3 The Structure and Dynamics of Populations 25
4 Sexual Reproduction 46
5 Asexual Reproduction 58
6 From Seed to Seedling 71
7 Growing Up, Getting Old and Dying 85
8 Competition 97
9 Herbivory, Parasitism and Mutualism 110
10 Basic Community Concepts and Diversity 124
11 Community Dynamics: Succession and Assembly 141
12 Landscape Scales and Invasive Species 164
13 Molecular Ecology: Applications for Invasive Plants 177
14 Plant Invasions: a Synthesis 186
Glossary 198
Subject Index 203
Species Index 211
v
Preface to the 2nd Edition
Our goal in writing this book was to describe how and why plant invasions occur. The book attempts to
explain the ecological principles that are important in understanding the potential for a species to become
invasive. We think students should understand the ecology of invasive plants and how this knowledge can
be used to facilitate management. Ecology is central to our understanding of how and why plant species
invade, and yet there are few books that make this connection. This is the niche we hope to fill.
The book was designed as a teaching text for advanced undergraduate students. No extensive ecological
background is assumed, although some basic biology is required. At the beginning of each chapter, we have
listed the concepts that will be addressed. These can be used as an overview of what is to come, and to assist
the reader when reviewing the material. For the instructor, we have designed this book so that the material
could be covered in a single-term course by covering approximately one chapter per week. We have tried to
write the book and arrange the material so that it is presented in a clear, precise and concise manner, and to
include only pertinent information. If we have done our job well, students should be able to read and under-
stand all the information. We have used common names throughout the text, with Latin names given the first
time that the species is mentioned in each chapter. We did this because common names are easier to remem-
ber when first learning about a species. A species list of common and Latin names is provided at the end of
the book.
At the end of each chapter there will be questions that refer to an invasive plant species of your (the stu-
dent’s) choice (i.e. a case study). The plant can be an established invasive species, or perhaps a new species
that may have potential to invade your local community You will be asked to summarize information that
is known about your plant species in relation to the material discussed in each chapter. There may be a lot
or very little information available to you. The idea behind this is to apply the ecological principles you learn
in the chapter to an invasive species of interest, and to give you practice researching a topic. Our hope is that,
by the end of the book, you will have created a case history of your chosen plant.
We have made a number of changes to this second edition from the first, which was published by CABI in
2003 as Weed Ecology in Natural and Agricultural Systems. We have removed the chapters that focused
solely on experimental methods and added chapters on the newer fields of landscape and molecular ecology.
In addition we have updated the literature.
We thank our publisher CABI for their help and encouragement with this second edition. Of course we
accept the responsibility for any errors that occur.
Finally, we thank our spouses, David Beattie, Tara Murphy and Josee Lapierre, who once again throughout
the writing of this second edition heard way more about ‘the book’ than they ever wanted, but kept smiling
and nodding their heads anyway. We dedicate this second edition to them.
vi
Introduction to Invasion Ecology
1
Producing and EatCionncgep tMs eat
● The terms invasive, colonizer, weed and others are often used in overlapping and conflicting manners.
● An invasion is the geographical expansion of a species into an area not previously occupied.
● Both native and non-native species can be invasive.
● Most invasions fail.
● The impact of an invasion depends on the area covered by the species, its abundance and the effect per
individual.
● Invasion meltdown is the acceleration of impacts on native ecosystems due to synergistic interactions.
1.1 Introduction invasive species (Sheley and Petroff, 1999; Myers
and Bazely, 2003; Liebman et al., 2007; Clout and
It may be tempting for you to start this book
Williams, 2009), or provide a detailed description
with Chapter 2. After all, the real information
of the biology of individual invasive species with-
doesn’t start until then, and exam questions
out providing a broad background (Czarapata,
rarely focus on what you learn in Chapter 1.
2005; Young and Clements, 2009). Here we focus
BUT Chapter 1 is important because it sets the
on the underlying ecological principles that explain
tone for what is to follow. A Shakespearean play
the process of plantinvasions.
or an opera always begins with a prologue. If
There are a number of excellent plant ecology
you walk in after the prologue has finished, you
texts (e.g. Barbour et al., 1999; Gurevitch et al.,
will certainly follow the plot and enjoy the play,
2006). This book was not designed to replace a
but you might not understand the ‘why’ of the
good, comprehensive text on basic ecological the-
characters’ actions. Consider this chapter a pro-
ory. Rather, its purpose is to examine invasive plant
logue. You may already know much of what we
species in systems from agricultural and natural
are about to say, and you may not be tested on
communities. Whether an invasive plant is in a
it, but it will put what you are about to learn
natural community or a highly managed farm, the
into context.
underlying questions and principles will be the
In this book, our goal is to provide you with a
same. All types of ecological systems are controlled
basic ecological understanding of how plants
by the same processes.
invade natural, disturbed and agricultural ecosys-
tems. Whether an invasive plant is in a natural
community or a highly managed farm, the under-
1.2 Levels of Ecology
lying questions and principles will be the same.
A number of books are available on plant inva- The word ecology was derived from the German
sions; however, they often assume an in-depth word (oekologie), which was derived from the
understanding of ecological principles (Mooney Greek words oikos, meaning ‘house’, and logos,
et al., 2005; Sax et al., 2005; Cadotte et al., 2006), meaning ‘the study of’. Thus, ecology is the study of
focus heavily on the control and management of organisms and their environment. We can divide the
©CAB International 2010. Invasive Plant Ecology in Natural and Agricultural Systems, 1
2nd Edition (B. Booth et al.)
environment into biotic (living) and abiotic (non- ● an alien in a semi-natural habitat (Stirton, 1979;
living) factors. Examples of biotic factors are com- Macdonaldet al., 1989)
petition and herbivory. Abiotic factors can be ● a native or non-native entering any new habitat
physical (e.g. temperature, light quality and quan- (Mack, 1985; Gouyon, 1990)
tity), or chemical (e.g. soil nutrient status). ● a native or non-native that is increasing in popu-
The field of ecology is vast. It is concerned with lation size (Joenje, 1987; Mooney and Drake,
areas as diverse as the dispersal of seeds, competi- 1989; Le Floch et al., 1990)
tion within and between species, and nutrient ● any non-native increasing in population size
cycling through ecosystems. Each of these oper- (Prach and Wade, 1992; Binggeli, 1994;
ates on a different temporal and spatial scale and Rejmánek, 1995)
each has a different focus. Thus, they all ask dif- ● any non-native species (Kowarik, 1995).
ferent types of questions, and require a different
Colautti and MacIsaac (2004) summarized more
protocol to answer them. For convenience, eco-
recent definitions of an invasive species as:
logical questions can be categorized into different
scales: ● a non-native species (Goodwin et al., 1999;
● Molecular ecology examines how DNA is Radford and Cousens, 2000)
● a native or non-native species that has colonized
expressed as traits that may allow plants to
natural habitats (Burke and Grime, 1996)
invade.
● Individual organisms can be studied to examine ● a widespread non-native species (van Clef and
Stiles, 2001)
how abiotic factors affect their physiology and
● a widespread non-native species that has a neg-
phenology.
● Groups of individuals of the same species can be ative effect on habitat (Davis and Thompson,
2000; Mack et al., 2000).
studied to look at population-level processes.
● Groups of co-occurring populations of different
Clearly, there is little consensus on what invasive
species can be studied to ask community-level
means. Similar problems occur with other terms,
questions.
such as weed. Weeds have typically been defined as
● Interactions between a community and its abiotic
‘plants which are a nuisance’ (Harper, 1960) or ‘a
factors can be studied to answer landscape- and
plant where we do not want it’ (Salisbury, 1961).
ecosystem-level questions.
Barbour et al. (1999) defined a weed as a ‘non-
native invasive plant’ and they distinguished between
Each of these categories blends into the next.
‘invasive plants’ that invade only natural or slightly
They are not discrete units of study, rather they
disturbed habitats, and ‘pest plants’ that interfere
are useful, practical and somewhat arbitrary
with agricultural or managed natural areas. This
divisions which help to simplify the understand-
definition, however, requires us to further define
ing of invasion ecology. In this book we discuss
non-native and invasive, and to separate natural
population ecology (Chapters 2–7), interactions
from disturbed habitats. These definitions are based
among populations (Chapters 8 and 9), commu-
on our perceptions of the impact of the plant.
nity ecology (Chapters 10 and 11), landscape
Similarly, the terms invader and colonizer have often
ecology (Chapter 12), and molecular ecology
been used in a conflicting manner. The distinctions
(Chapter 13). In the final chapter (14) we incor-
between them are quite subtle and result from differ-
porate all levels of ecology to discuss the process
ing viewpoints. According to Rejmánek (1995),
of plant invasions.
weeds interfere with human land use; colonizers are
successful at establishing following disturbance; and
invaders are species introduced into their non-native
1.3 What’s in a Name?
habitat. There is substantial overlap among these
Every book on invasive species must first start terms. A plant may be considered as only one of
with an attempt at defining terms. Many attempts these, or it may be included in all of these categories
have been made to define invasive and other terms (Fig. 1.1). Given the confusion of terminology, we
describing a species’ status. Pyšek (1995), for take a broad view of the term invasive, defining it as
example, reviewed definitions of an invasive spe- a species that has a negative ecological or economic
cies and found that it has been described as: effect on a natural or managed ecosystem.
2 Chapter 1
Anthropogenic viewpoint: Ecological viewpoint:
interferes with objectives or pioneers in succession
requirements of people
Weeds
Colonizers
e
z
si
e
g
Invaders n
a
R
Biogeographical viewpoint:
introduced, exotic, alien,
non-native species
Fig. 1.1. Weeds, colonizers, and invaders are similar
concepts but result from differing viewpoints (redrawn
from Rejmánek, 1995).
Time
It is important to differentiate species that are Fig. 1.2. The process of invasion.
invasive from species that are introduced. While
most invasive species are introduced, this is not
size will level off. In Chapters 2 to 13 of this text
always the case. For example, in the north-eastern
we will discuss individual processes that influence
USA, the native hay-scented fern (Dennstaedtia
one or several of these stages of invasion, and in
punctilobula) becomes invasive under conditions of
the final chapter we synthesize these individual
intensive browsing by white-tailed deer and the
chapters and revisit the invasion process.
thinning or removal of overstorey tree canopy (de
la Cretaz and Kelty, 1999). In addition, not all
introduced species become invasive. Many plant Most invasions fail, but some will succeed
species are intentionally introduced for use as
Most invasions fail. That is, most species when
crops, for erosion control, or for aesthetic reasons
introduced into a community will not survive.
(e.g. in gardens). While some introduced species
A successful invasion is a rare event (Williamson,
have become invasive, many will persist in small
1996). How rare? Williamson (1996) proposed
self-sustaining populations but will not expand in
the ‘tens rule’ to describe how approximately
range or will remain at low density. Furthermore,
10% of species pass through each transition from
many introduced species would go extinct in their
being imported (dispersal) to becoming casual
introduced range without human management (e.g.
(introduced to the wild) to becoming established,
maize will never become invasive in Canada).
and finally becoming an invasive (Williamson
1996) (Fig. 1.3). This is a rough rule, but has been
1.4 What is an Invasion? shown to apply around the world, under many
situations (Williamson and Fitter, 1996). What is
Elton (1958) was the first person to formalize the
evident from this rule is that successful invasions
study of invasion ecology, recognizing that inva-
are rare (Williamson, 1996).
sions of introduced species could have global
Our knowledge of why an invasion fails can be
impacts (Richardson and Pyšek, 2008). Since
quite limited (Rejmánek, 1999). Successful invaders
then, interest in invasion ecology has grown. An
are obvious, but failed invaders are not; therefore,
invasion is ‘the geographical expansion of a spe-
it is difficult to study the process of a failed inva-
cies into an area not previously occupied by that
sion. Some reasons that invasions fail are (Crawley,
species’ (Vermeij, 1996). The process that a plant
1987; Lodge, 1993):
species goes through when it invades has a series
of stages. Initially, following a species’ introduc- ● inappropriate abiotic conditions for the species
tion, its geographical expansion occurs very to survive
slowly (Fig. 1.2). This lag period can last as long ● introduced species are outcompeted by other
as centuries. Following the lag period, there species
may be exponential expansion of the species’ ● presence of natural enemies such as herbivores
range. Eventually, the increase in a species’ range and diseases
Introduction to Invasion Ecology 3