Mediterranean-Type Ecosystems: The Function of Biodiversity

382 Pages·1995·11.668 MB·English

by  R. J. Hobbs, D. M. Richardson, G. W. Davis (auth.), Dr. George W. Davis, Dr. David M. Richardson (eds.)

Ecological Studies, Vol. 109
Analysis and Synthesis
Edited by
O.L. Lange, Wiirzburg, FRG
H. A. Mooney, Stanford, USA
H. Remmert t, Marburg, FRG
Ecological Studies
Volumes published since 1989 are listed at the end of this book.
G.W. Davis D.M. Richardson (Eds.)
Mediterranean-Type
Ecosystems
The Function of Biodiversity
With 67 Figures and 21 Tables
Springer
Dr. GEORGE W. DAVIS
National Botanical Institute
Stress Ecology Research Unit
Private Bag X7
7735 Claremont
South Africa
Dr. DAVID M. RICHARDSON
University of Cape Town
Institute for Plant Conservation
Botany Department
7700 Rondebosch
South Africa
Front cover: For millennia human societies in the Mediterranean Basin have been exploring
the balance between Nature's ability to provide, and Humanity's need to consume. The cover
illustration is a design by Peithinos (6th century B.C.), and depicts the marine deity Thetis,
granddaugther of the earth goddess Gaea, enploying water, fire, serpents and wild beasts to
resist advances by the mortal Peleus. Capitulation and consummation in this encounter resulted
in the birth of the hero Achilles, a paradoxical symbol of both human strength and frailty.
Library of Congress Cataloging-in-Publication Data. Mediterranean-type ecosystems: the function of
biodiversity/ G.W. Davis, D.M, Richardson, eds. p. cm. - (Ecological studies; vol. 109) Includes
bibliographical references and index.
I. Mediterranean-type ecosystems. 2. Biological
diversity. I. Davis, G.W. (George W.), 1947-. II. Richardson, D.M-. (David M.), 1958-. III. Series:
Ecological studies; v. 109. QH541.5.M44M43 1994574.5' 262-dc20 94-34429
ISBN-I 3: 978-3-642-78883-3 e-ISBN-13: 978-3-642-78881-9
DOl: 10.1007/978-3-642-78881-9
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© Springer-Verlag Berlin Heidelberg 1995
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Foreword
The threat, and reality, of global change has caused us to examine more
closely the controls on the abundances and distributions of organisms. As
a result, the study of biogeography and palaeoecology is receiving renewed
attention. New insights are being attained that are providing the tools to
make predictions of how the world's biotic systems will be reconfigured
due to changing land use, a changing atmosphere and a changing climate.
An additional element of global change is the biotic rearrangements that
are occurring on Earth due to biological invasions and biotic extinctions.
We have ample evidence of the massive intercontinental biotic exchanges
that are occurring and of the consequences of these invasions. We also
have indications of the great losses in biotic diversity that are occurring at
all levels, particularly now in the tropics. For some reason more attention
has been given to documenting these losses than in understanding the
ecological consequences of the new biotic world in which we live.
To address this issue, SCOPE (Scientific Committee on Problems of the
Environment) initiated a program to examine the "ecosystem function of
biodiversity". Specifically, the program addresses two basic questions:
"How do species affect ecosystem processes in the both the short and long
term and in the face of global change?" and, "How is system stability and
resistance affected by species diversity and how will global change affect
these relationships?". These questions are species-centered, as have been
most of the issues related to biodiversity. However, as the program has
developed, additional attention has been given to the other changing dimen
sions of biodiversity, such as populations, communities, and even
landscapes.
The basic approach of the SCOPE program has been to examine the
functioning of the major ecosystems of the Earth to assess how they have
been impacted by species losses and additions as well as by habitat
fragmentation and disturbance. This review provides us with the first global
assessment of the nature of the problem. The next phase of the, program,
to be developed by the International Geosphere-Biosphere Program (IGBP),
will refine the assessment by launching a specific program to provide new
information from experiments specifically designed to address the
diversity/function problem rather than relying on the imperfect information
VI Foreword
derived from inadvertent "experiments" instigated by human activities or
from natural environmental fluctuations.
This Volume is one of the first products of the SCOPE global as
sessment of the ecosystem consequences of changes of biodiversity. Not
surprisingly, the first group to achieve this synthesis are the scientists of the
mediterranean regions of the world. As documented in the introductory
chapter, these scientists have had a long history of international col
laboration and of ecosystem comparative analysis. Further, they live and
work in natural ecosystems of extraordinarily rich biodiversity, and yet
ones that have been heavily impacted by human activities. These cir
cumstances have led to this pathbreaking volume on the relationship
between structure and function of natural ecosystems.
Stanford, Autumn 1994 Harold Mooney
Preface
This book is set within the broad research framework of a project, under
the auspices of IUBS, SCOPE and UNESCO, which is aimed at providing
insights into ecological complexity and the way in which ecosystems will
respond to global change (see Foreword). That is the top-down perspective.
From the bottom up, there have been a series of events which have
gathered momentum over several years, and of which this Volume is a
staging point. The process began when the mediterranean-type ecosystems
(MTEs), which occur in the Mediterranean Basin, California, Central Chile,
southern and southwestern Australia, and the southern and southwestern
Cape Province of South Africa, were targeted as a focal biome-type for the
project. Brian Huntley, member of the SCOPE Committee and Chief
Director of the National Botanical Institute in South Africa, was assigned
to coordinate this project.
Regional synthesis meetings were arranged in the five regions. The
proceedings of the Australian meeting were published as a book (Hobbs
1992), and selected contributions from the South African synthesis meeting
appeared in a special issue of the South African Journal of Science (Vol.
90 part 6) in 1994. Meetings and consultations in the other regions were
directed at producing the framework for the synthesis chapters that appear
in this Volume. An international meeting was convened in Cape Town in
September 1992 to coincide with the South African synthesis conference.
At this meeting, delegates from Australia, California, Chile and the
Mediterranean Basin presented draft summaries of their regional syntheses.
These, the South African contributions, and other related issues were
debated at a 3-day workshop at Springfield on the Agulhas Plain (Davis et
al. 1993; Richardson and Cowling 1993). The constructive interaction bet
ween delegates at the workshop led to far-reaching discussion on the
subject, and the chapters in this book emerged from these deliberations.
The process of producing this book has been very instructive to us, and
we feel that the contributions have explored an exciting new domain at the
interface between ecology and the search for management strategies to
ensure the sustained utilization of natural resources. Perspectives of the
relationship between humans and natural ecosystems are clearly different
for each region. These range from an evolved association measured in
vm Preface
millennia in the Mediterranean Basin, to the rapid and utilitarian transfor
mation of Western Australian kwongan, mallee and woodland for wheat
production. As South Mricans, we had yet another perspective. The
compilation of this book coincided with a dramatic restructuring of the
political order in our country. This process certainly carries the threat of
instability, but it also provides exciting opportunities for establishing new
social paradigms. Implications for sustainable management of the human
environment are obvious. It is well known that South African mediter
ranean-type ecosystems are a "hotspot" of biodiversity (Cowling et al.
1992). They are also important water catchments, and offer a key to foreign
investment through ecotourism. A new social order could hasten the demise
of this repository of biodiversity and source of human sustenance.
Alternatively, it could initiate a new awareness for nurturing the fragile
basis for human survival. The key to conserving these ecosystems lies in
promoting its wise use as a resource. Reconciling conservation with
exploitation is critical, and the issues addressed in this Volume are totally
relevant to that issue. It is against that backdrop that we assembled this
Volume, hoping that the future will see a greater interaction between
humanity and science, without compromising the foundation of either.
We trust that the hard work and commitment of the chapter authors is
as much appreciated by the readerShip as it is by the editors. Also much
appreciated is the input by the chapter reviewers and general advisers,
whose sole interest has been the promotion of ecology. We thank William
Bond (Botany Department, University of Cape Town), Richard Groves
(Division of Plant Industry, CSIRO, Canberra), Peter Grubb (Botany
School, University of Cambridge), Ian Macdonald (Southern Africa Nature
Foundation, Stellenbosch), June Juritz (Department of Statistical Sciences,
University of Cape Town), John Lawton (Imperial College, London),
Eugene Moll (Department of Management Studies, Gatten College,
University of Queensland), Ian Noble (Research School of Biological
Sciences, Australian National University, Canberra), Marcel Rejmanek
(Botany Department, University of California, Davis), Jacques Roy
(CNRS-CEPE, Centre Louis Emberger, Montpellier), Mike Rutherford
(National Botanical Institute, Cape Town), Bob Scholes (Division of Forest
Science and Technology, CSIR, Pretoria), E-Detlef Schulze (University of
Bayreuth), Dave Wardle (Department of ClassiCS, University of Cape
Town), Brian van Wilgen (Division of Forest Science and Technology,
CSIR, Stellenbosch), Ed Witkowski (Botany Department, University of the
Witwatersrand) and Paul Zedler (Biology Department, San, Diego State
University). We also thank Shirley Cowling, Ann Green and Debbie Hunter
for their help during the production of the book. For covering travel
expenses of the foreign delegates, and providing logistic and secretarial
support at the Cape Town symposium and Agulhas Plain workshop, we
Preface IX
thank the South African Foundation for Research Development in Pretoria.
For support of the whole MTE synthesis project we are indebted to the
National Botanical Institute and its Director, Brian Huntley. The Institute
for Plant Conservation at University of Cape Town is also acknowledged
for its direct and indirect support.
We want to thank, amongst others, the following for permission to
reproduce original or modified material: Annual Reviews Incorporated (Fig.
5.2); Cambridge University Press (Table 1.1); the Ecological Society of
America (Fig. 4.8); the Foundation of Research Development (South
Africa) (Fig. 1.5 and Table 1.2); Kluwer Academic Publishers (Figs. 2.8,
4.5 and 4,6); Oxford University Press (Figs. 1.6, 6.1 and 6.3); Springer
(Figs. 1.4, 3.16, 3.18, 3.19, 4.2, 5.3 and 5.4); and the Staatliche Museum,
Berlin (cover illustration).
References
Cowling RM, Holmes PM, Rebelo AG (1992) Plant diversity and endemism. In: Cowling
RM (ed) The ecology of fynbos: Nutrients, flre and diversity, Oxford University Press,
Cape Town, pp 62-112
Davis GW, Keeley JE, Lamont BB (1993) Biodiversity and ecosystem function in
mediterranean-type ecosystems. Bull S Afr Inst Eco1 11(3): 3-5
Hobbs RJ (ed) (1992) Biodiversity in mediterranean ecosystems in Australia. Surrey Beatty.
Chipping Norton, NSW
Richardson DM, Cowling RM (1993) Biodiversity and ecosystem processes: opportunities
in mediterranean-type ecosystems. Trends Ecol Evol 8: 79-81
George Davis and Dave Richardson
Cape Town, Autumn 1994
Contents
1 Mediterranean-Type Ecosystems:
Opportunities and Constraints for Studying
the Function of Biodiversity
RJ. Hobbs, D.M. Richardson and G.W. Davis (8 Figures) 1
1.1 Focus on Mediterranean-Type Ecosystems . . . . . . . . . . . . .. 1
1.2 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
1.3 Why Study Biodiversity and Ecosystem Function? . . . . . . .. 5
1.4 Linking Diversity and Ecosystem Function ............. 7
1.5 Mediterranean-Type Ecosystems:
Similarities and Differences Between Regions ........... 11
1.5.1 Climate . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . 11
1.5.2 Soils ........................................ 12
1.5.3 Vegetation .................................... 15
1.5.4 Human Transformation . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.6 History of Research on Mediterranean-Type Ecosystems . . .. 23
1.7 Opportunities for Studying Links Between Biodiversity
and Ecosystem Function in MTEs ................... 28
References ..................................... '. . . . 32
2 Biodiversity and Ecosystem Function in the Mediterranean
Basin: Human and Non-Human Determinants
J. Blondel and J. Aronson (9 Figures) ................. 43
2.1 Introduction ................................... 43
2.2 Geography, Climate and Habitat Diversity .............. 46
2.2.1 Geography .................................... 46
2.2.2 Climate ................................. : .... 47
2.2.3 Habitat Diversity ............................... 49
2.3 Patterns of Mediterranean Diversities
in Relation to Space and Time . . . . . . . . . . . . . . . . . . . . . . 49
2.3.1 Flora and Vegetation ............................. 49
2.3.2 Vertebrates ................................... 53