Ecology and Evolutionary Biology of Clonal Plants: Proceedings of Clone-2000. An International Workshop held in Obergurgl, Austria, 20–25 August 2000

375 Pages·2002·9.244 MB·English

by  Josef F. Stuefer, Brigitta Erschbamer (auth.), J. F. Stuefer, B. Erschbamer, H. Huber, J.-I. Suzuki (eds.)

ECOLOGY AND EVOLUTIONARY
BIOLOGY OF CLONAL PLANTS
Proceedings of Clone-2000. An International Workshop
held in Obergurgl, Austria, 20-25 August 2000
Edited by
J.F. STUEFER
Nijmegen University, Nijmegen, The Netherlands
B. ERSCHBAMER
University of Innsbruck, Innsbruck, Austria
H. HUBER
Brown University, Providence, USA
J.-I. SUZUKI
Tokyo Metropolitan University, Tokyo, Japan
Reprinted from Evolutionary Ecology
Vol 15, Nos 4-6 (2001)
....
"
SPRINGER-SCIENCE+BUSINESS MEDIA, BV.
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A.C.I.P Catalogue record for this book is available from the Library of Congress.
ISBN 978-90-481-6047-1 ISBN 978-94-017-1345-0 (eBook)
DOI 10.1007/978-94-017-1345-0
Printed on acid~free paper
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© 2002 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 2002
Softcover reprint of the hardcover 1s t edition 2002
No par! of the material protected by this copyright notice many be reproduced or
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Table of Contents
STUEFER, J.F., ERSCHAMBER, B., HUBER, H. and SUZUKI, J.-1. /
The ecology and evolutionary biology of clonal plants: an introduction to
the proceedings of Clone-2000 223-230
McLETCHIE, D.N., GARciA-RAMOS, G. and CROWLEY, P.H. /
Local sex-ratio dynamics: a model for the dioecious liverwort Marchantia
infiexa 231-254
BARSOUM, N. / Relative contributions of sexual and asexual regenera
tion strategies in Populus nigra and Salix alba during the first years of
establishment on a braided gravel bed river 255-279
WINKLER, E. and FISCHER, M. / The role of vegetative spread and
seed dispersal for optimal life histories of clonal plants: a simulation study 281-301
YU, F., CHEN, Y. and DONG, M. / Clonal integration enhances survival
and performance of Potentilla anserina, suffering from partial sand burial
on Ordos plateau, China 303-318
OBORNY, B. and KUN, A. / Fragmentation of clones: how does it in
fluence dispersal and competitive ability? 319-346
PRICE, E.A.C., GAMBLE, R., WILLIAMS, G.G. and MARSHALL,
C. / Seasonal patterns of partitioning and remobilization of 14C in the in
vasive rhizomatous perennial Japanese knotweed (Fallopia japonica
(Houtt.) Ronse Decraene) 347-362
KLIMES, L. and KLIMESOV A, J. / The effects of mowing and fertiliza
tion on carbohydrate reserves and regrowth of grasses: do they promote
plant coexistence in species-rich meadows? 363-382
TAMM, A., KULL, K. and SAMMUL, M. / Classifying clonal growth
forms based on vegetative mobility and ramet longevity: a whole commu
nity analysis 383--401
HERBEN, T. and SUZUKI, 1.-1. / A simulation study of the effects of
architectural constraints and resource translocation on population struc
ture and competition in clonal plants 403-423
WATSON, M.A., SCOTT, K., GRIFFITH, J., DIETER, S., JONES, C.S.
and NANDA, S. / The developmental ecology of mycorrhizal associations
in mayapple, Podophyllum peltatum, Berberidaceae 425-442
Electronic journals at
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Contact your librarian for more information
IV TABLE OF CONTENTS
TOLVANEN, A., SCHRODERUS, l. and HENRY, G.H.R. / Age- and
stage-based bud demography of Salix arctica under contrasting muskox
grazing pressure in the High Arctic 443-462
BIRCH, C.P.D. / The influence of position on genet growth: a simulation
of a population of bracken (Pteridium aquilinum (L.) Kuhn) genets under
grazing 463-483
SACHS, T. / Developmental processes and the evolution of plant c10nality 485-500
ECKERT, e.G. / The loss of sex in clonal plants 501-520
CHARPENTIER, A. / Consequences of clonal growth for plant mating 521-530
COLLADO-VI DES, L. I Clonal architecture in marine macroalgae: eco
logical and evolutionary perspectives 531-545
GOUGH, L., GOLDBERG, D.E., HERSHOCK, e., PAULIUKONIS,
N. and PETRU, M. / Investigating the community consequences of com
petition among clonal plants 547-563
FISCHER, M. and KLEUNEN, M.V. / On the evolution of clonal plant
life histories 565-582
PAN, l.l. and PRICE, l.S. / Fitness and evolution in clonal plants: the
impact of clonal growth 583-600
.... Evolutionary Ecology 15: 223-230, 2002.
" © 2002 KIUlver Academic Publishers.
The ecology and evolutionary biology of clonal plants:
an introduction to the proceedings of Clone-2000
JOSEF F. STUEFER,I BRIGITTA ERSCHBAMER,2
HEIDRUN HUBERL3 and JUN-ICHIROU SUZUKI4
I Department olEcology, Experimental Plant Ecology, Nijmegen University. Toernooiveld 1.6525 ED
Nijmegen, The Netherlands; 2Institute of Botany, University ol lnnsbruck, StermvartestrajJe 15, A-
6020 lnnsbruck. Austria; 3 Department (}lEcology and Evolutionary Biology. Brown University, 02912
Providence, RI. USA; 4Department ol Biological Sciences, Tokyo Metropolitan University, Tokyo
192-0397, Japan
Received 5 December 200 I; accepted 18 January 2002
Spontaneous self-cloning or clonality is a wide-spread phenomenon in the plant
kingdom, which also occurs in lichens, fungi and in some groups of animals.
Clonal growth of plants can manifest itself in many ways such as in the for
mation of ramets on above- and belowground creeping stems (such as in
Strawberries, Bracken or Bamboo), by root suckering (such as in Pawpaw,
Robinia pseudo acacia, or Ailanthus) or in the vegetative production of plantlets
and bulbi Is on aerial plant parts (such as in several lilies, grasses, and in the
genus Bryophyllum). Clonality can also be achieved by fragmentation of the
plant body followed by the regeneration of plant individuals from fragments
(such as in many bryophytes and algae), or by the release of asexually produced
seeds in apomictic species (such as in dandelions). The common feature and
defining principle of all types of clonality is the asexual, vegetative production
of offspring individuals, which are genetically identical (or at least extremely
similar) to each other and to the parent plant. In other words, clonality is
characterized by the fact that offspring individuals are produced from somatic
tissue without passing through regular meiotic cell cycles, thereby by-passing
sexual recombination of the genetic material.
Clonality in itself, and the various ways by which it is realized in plants, has
a wide array of ecological and evolutionary consequences. These phenomena
are the central and unifying theme of the collection of papers presented in this
Special Issue. A number of aspects and implications of clonality have received
considerable attention from plant ecologists, and to a lesser degree of physi
ologists, developmental biologists and evolutionary ecologists over the last few
decades. These aspects of clonality include the modular and decentralized or
ganization of the clonal plant body, architectural plasticity and the mobility of
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clones, the ability to internally transfer resources and information between
ramets in several clonal growth forms, and the balance between sexual and
asexual propagation in clonal species and its potential impact on the genetic
diversity of clonal plant popUlations. As a consequence, a vast body of liter
ature is available which deals specifically with phenomena directly or indirectly
linked to clonality in plants. A number of equally interesting and important
aspects of clonality, however, have received considerably little attention in the
past. Some of them are mentioned explicitly at the end of this introduction.
This volume contains the proceedings of an international workshop (Clone-
2000, held in Obergurgl, Austria, in August 2000), which aimed at revealing the
diversity of current research on ecological and evolutionary aspects of clonal
growth in plants and to stimulate discussion and cooperation between different
sub-disciplines. The collection of papers presented here follows a series of
workshop proceedings and edited books dedicated to the study of clonal plant
biology (Jackson et al., 1985; van Groenendael and de Kroon 1990; Callaghan
et al., 1992; Herben et al., 1994; Oborny and Podani 1995; de Kroon and van
Groenendael 1997; Price and Marshall 1999). The general purpose of these
proceedings is to give examples of recent empirical and theoretical research on
clonal plants and to provide a forum for new ideas and conceptual progress
regarding various aspects of plant clonality. It should be noted, however, that
these proceedings cannot provide a comprehensive survey of this field of sci
ence. They should rather be seen as a snapshot that captures some of the
diversity of ongoing research, and that aims at identifying possible avenues for
prospective investigations. Future reviews, proceedings and text books may
provide an answer to the question whether the research and conceptual ini
tiatives presented in this volume will be fruitful in generating new insight into
specific research topics and in stimulating discussion and advance in various
fields of clonal plant research.
The proceedings consist of two main sections, containing a number of Re
search Articles, and conceptual or review papers (Perspectives), respectively.
The sequence of articles within these sections is somewhat arbitrary. As a
consequence, there are numerous cross-links between the individual papers,
which are not evident from the unavoidably linear arrangement of manuscripts
in the volume. The following paragraphs provide a brief summary of the
content and main messages of the individual papers.
The first three research articles deal with ecological and evolutionary im
plications of vegetative and sexual propagation in clonal plants. McLetchie
et al. use a modeling approach to investigate the dynamics of sex ratios in a
clonal, dioecious liverwort. Their study suggests an important role of clonal
growth for determining local sex ratios in this species, and it points at meta
population dynamics as a possibly crucial, but so far unexplored factor for the
maintenance of sex in dioecious clonal plants. Barsoum presents an empirical
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study of the relative importance of sexual and asexual propagation in two tree
species from flood plains along rivers. The results show a clear spatial and
temporal differentiation between the two modes of regeneration. Barsoum
suggests that the balance between sexual and asexual recruitment may repre
sent an adaptive trait ensuring the long-term persistence of the species in their
unpredictable and naturally disturbed habitat. This is an important message
for ecologists and conservation biologists alike. Winkler and Fischer develop a
simulation model to predict optimal investment patterns into vegetative spread
and seed production in a clonal plant. The main conclusion emerging from this
study is that the spatial structure of habitats, such as the scale of disturbance,
can exert dispersal-driven selection pressures on the balance between sexual
and asexual propagation, and that trade-offs are likely to constrain the evo
lution of optimal life histories with respect to the balance between sexual and
asexual propagation.
The following two articles deal with ecologicall consequences of physiological
integration and disintegration in clonal plants. The experimental study by Yu
et al. shows that clonal integration enables a stoloniferous species to better
withstand partial burial by sand. This trait may not only have an adaptive
value in semi-arid habitats with moving sand, but it could also render stolo
niferous and rhizomatous species suitable candidates for re-vegetation and soil
stabilization projects in desertified environments. Oborny and Kun use an
individual-based simulation model to investigate the consequences of clonal
integration and disintegration for dispersal and competition in spatially hetero
geneous environments. This paper contains novel ideas and testable hypotheses
about the relationship between clonal integration (and splitting) on one hand,
and processes such as population dynamics of ramets and genets, dispersal,
competition and coexistence, and optimal life-history strategies on the other.
Oborny and Kun provide a formalized conceptual framework for an advanced
understanding of the ecology and evolution of integration and disintegration in
clonal plant species.
Next comes a set of two papers containing studies on carbon storage (and
remobilization) in clonal plant species. These studies emphasize the importance
of storage for the invasiveness, the competitive ability and regeneration ca
pacity of clonal plant species. Price et al. present a radio-active tracer experi
ment which aimed at quantifying the growth and seasonal pattern of carbon
movement and storage in a highly invasive clonal species. The authors con
clude that the ability for efficient storage and remobilization of carbon in
rhizomes enables this species both to survive in its native, harsh environment
and to become a successful, aggressive invader in alien ecosystems. KlimeS and
Klimesova investigate the effects of mowing and fertilization on the storage
and remobilization of different carbon compounds in three grass species. Their
manipulative field experiment provides evidence for the notion that storage of
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resources is a trait associated with potential dominance in grassland systems.
Mowing can suppress dominant species, thereby fostering coexistence and
species diversity.
The following two papers, however different in approach, aim at linking
variation in specifically clonal plant traits to population and community-level
phenomena. The comparative study by Tamm et al. identifies several clonal
growth and life-history types in a successional series of meadow communities.
An examination of the relative abundance of these types in the different
meadows suggests consistent (and yet unexplored) relationships between clonal
plant traits on one hand, and community structure and functioning on the
other. The simulation model by Herben and Suzuki explores the effects of
variation in clonal growth parameters and architectural traits on the spatial
dynamics of ramets and genets, and on competitive interactions between clonal
plants. The results suggest that architectural constraints can have direct con
sequences for ramet density, genet diversity and for the competitive ability of
individuals in clonal plant populations.
The research paper section ends with three studies dealing with different
aspects of biotic interactions between clonal plants, herbivores and mycorrhizal
fungi. Watson et al. investigate the degree and intra-clonal pattern of arbus
cular mycorrhizal associations in a rhizomatous herb. They found a remark
able relationship between the developmental stage of ramets and mycorrhizal
interactions. The underlying processes for intra-clonal differences in mycor
rhizal associations and their ecological implications clearly deserve further
study. Tolvanen et al. use age- and stage-based matrix models to study the bud
population dynamics of a dioecious, arctic willow under different grazing
pressures. The authors do not find evidence for selective grazing of male plants
which had previously been proposed as a mechanism behind female-based sex
ratios in some dioecious plants. The investigated species appears to buffer
grazing with an increased release of dormant buds. The long-term effects of this
response, however, remain a question for continued research. Birch presents a
spatially explicit simulation model to investigate the spatio-temporal dynamics
of bracken under different grazing pressures. Based on the results of this study,
the author proposes that any mechanism generating non-linear spatial patterns
will also generate complex genet dynamics, with potentially far-reaching con
sequences not only for the population dynamics of ramets and genets but also
for population genetics, competition and spatio-temporal community pat
terning.
The second section of the proceedings contains a collection of review and
idea/discussion papers which take up very different issues related to clonality in
plants. Sachs presents a detailed discussion of developmental processes that
are, and characteristic for clonal plants. After reaching the conclusion that no
unique developmental processes are required for clonality, that clonal growth
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results from quantitative modifications of processes that are common in most
land plants, Sachs moves on to explore possible developmental mechanisms
whose modification during evolution may have led to the multiple origin of
clonality. These considerations result in a number of original questions
and testable hypotheses which provide intriguing opportunities for future re
search.
In the next contribution Eckert reviews ideas and studies on variation in
sexual vs. asexual propagation, particularly emphasizing possible causes and
ecological, genetical, and evolutionary implications of the loss of sexual re
production in clonal plant species. Largely based on a few well-studied model
systems, Eckert proposes that genetic infertility originates from the accumu
lation of sterility mutations in populations where sexual recruitment is im
paired by unfavorable environmental conditions. The paper also includes a
number of open research questions which are of particular interest for a better
understanding of the ecology, evolution and genetics of (extreme) variation in
sexual reproduction in clonal plants.
The paper by Charpentier succinctly explores and summarizes potential ef
fects of clonal growth on pollen transfer and mating patterns, proposing that
the spatial structure of clones (especially the arrangement of flowering ramets)
can both increase floral display and pollinator attraction, and at the same time
impose serious constraints and evolutionary challenges through an increased
risks of geitonogamy (pollination between flowers of the same plant). Char
pentier stresses the importance of clonal architecture for determining mating
patterns in clonal species, concluding with the conjecture of likely co-evolu
tionary interactions between the spatial structure and the mating behavior of
clonal plant species.
Collado Vides introduces the clonal growth of marine macro-algae, a group
of organisms which is hardly represented in the ecological and evolutionary
literature on plant clonality. This introductory overview of different types of
clonal growth and life cycles in marine macro-algae provides an excellent basis
not only for novel experimental work but also for applying concepts and
methods developed for terrestrial clonal plants to this group of marine or
ganisms. In addition, macro-algae may provide a good model system to in
vestigate ecological and evolutionary questions relating to complex life cycles
that involve different forms of asexual propagation.
Gough et al. present a conceptual and methodological framework for in
vestigating the role of clonal plants and specific clonal plant traits for com
petitive interactions in a community context. They develop specific predictions
about how clonal architecture and physiological integration can affect com
petitive ability and community structure and they also suggest experimental
approaches to verify these predictions. Gough et al. 's contribution will hope
fully stimulate the interest of ecologists in the prominent role that clonal plant
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species play in many communities and ecosystems, and so promote experi
mental investigations in this area of research.
Fischer and van Kleunen review information on clonal plant life histories.
After having identified four main axes (trait complexes) along which clonal
plant life histories may evolve, the authors present a detailed analysis of the
prerequisites and implications, as well as a discussion of available information
on (adaptive) evolution in clonal plants. Fischer and van Kleunen conclude
that considerable research efforts are needed to fill the current gaps in our
knowledge about life-history evolution in clonal plants. They point at a
number of modern approaches and techniques that can help reach this goal.
In the final contribution, Pan and Price aim at formulating an integrative
framework for the study of fitness, selection and evolution in clonal plant
species. The authors stress the importance of clonal growth (local genet rep
lication) for the outcome of micro-evolutionary processes and they propose
that a unique form of selection (termed genotypic selection) is likely to con
tribute significantly to evolutionary changes in clonal plant populations. Pan
and Price express their hope that a clarification of the concepts of fitness,
selection and evolution will promote progress in the study and understanding
of the evolutionary biology of clonal plants.
It is clear from the diversity of contributions in this volume that clonal plant
research has become a relatively broad scientific field which enjoys the interest
of an increasingly wide community of ecologists and evolutionary biologists.
The collection of papers presented here, and the ideas, hypotheses, approaches
and aims encompassed by these papers suggests that clonal plant research has
widened considerably over the last years with respect to its objectives, methods,
and study systems. This trend seems likely to continue in future as scientists
from various ecological and evolutionary sub-disciplines realize that a con
siderable number of phenomena on the individual plant, the population and
the community level can directly be linked to clonality and its manifold im
plications (see above, and see contributions). Because they are so common in
nature, clonal plants have been, and they are, the objects of countless scientific
studies. Clonality as a subject of ecological and evolutionary research, however,
has long been confined to a relatively narrow set of conspicuous consequences
of clonality that are apparent in a small subset of clonal forms, such as
physiological integration, mobility and architectural flexibility in stoloniferous
and rhizomatous herbs. This Special Issue may help to widen and diversify
clonal plant research by promoting the notion that clonality has major re
percussions for ecological and evolutionary processes across a wide range of
spatio-temporal scales and across different levels of organization and for bio
logical interactions.
Various contributions in this volume clearly show that a number of previ
ously under-researched topics are currently being incorporated in the clonal
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