Plants on islands : diversity and dynamics on a continental archipelago

278 Pages·2006·14.58 MB·English

by  Cody

PLANTS ISLANDS
on

PLANTS ISLANDS
on
Diversity and Dynamics on a
Continental Archipelago
Martin L. Cody
UNIVERSITY OF CALIFORNIA PRESS
Berkeley Los Angeles London
University of California Press
Berkeley and Los Angeles, California
University of California Press, Ltd.
London, England
© 2006 by The Regents of the University of California
Library of Congress Cataloging-in-Publication Data
Cody, Martin L., 1941-
Plants on islands : diversity and dynamics on a continental archipelago /
Martin L. Cody.
p. cm.
Includes bibliographical references and index.
ISBN 0-520-24729-9 (case : alk. paper)
1. Island plants—British Columbia—Barkley Sound Region. 2. Plant
communities—British Columbia—Barkley Sound Region. 3. Vegetation
dynamics—British Columbia—Barkley Sound Region. 4. Phytogeography—
British Columbia—Barkley Sound Region. 5. Plant ecology—British
Columbia—Barkley Sound Region. I. Title.
QK203.B7C63 2006
581.7’5209711—dc22 2005037441
Manufactured in the United States of America
15 14 13 12 11 10 09 08 07 06
10 9 8 7 6 5 4 3 2 1
The paper used in this publication meets the minimum requirements of
ANSI/NISOZ39.48-1992 (R1997) (Permanence of Paper).
FOR DARYL ANN, ROSIE, AND TIM,
WITH LOVE AND THANKS FOR ALL OF OUR BAMFIELD SUMMERS

contents
Preface / ix Variation in Species Counts on
Islands / 56
1 • INTRODUCTION / 1
Cumulative Species Numbers / 62
2 • ISLANDS IN BARKLEY SOUND, BRITISH
Species Richness on Islands / 63
COLUMBIA / 6
Geography and History / 6
5 • NESTEDNESS AND ASSEMBLY RULES / 74
Geology and Topography / 9
Inferences from Species-by-Sites
Climate / 10 Matrices / 74
More Island Geography and Forest Species / 76
Topography / 13
Shoreline Habitats / 85
Flora and Vegetation / 23
Edge Habitats / 100
Methodological Notes / 30
6 • SPECIES TURNOVER IN SPACE AND TIME / 116
3 • ISLAND BIOGEOGRAPHY: CONCEPTS, THEORY,
Colonization and Extinction, Persistence
AND DATA / 36
and Turnover / 116
The Basic Model / 36
Species Turnover in Time, and Island
Some Embellishments / 38
Size / 124
Incidence Functions / 39
Species Turnover in Space / 128
Colonization and Extinction Data / 41
Historical Legacies / 50 7 • DISPERSAL SYNDROMES, INCIDENCE,
AND DYNAMICS / 138
Generalities, Specifics, and Modifications
of the M/W Model / 55 Dispersal in Plants: Options / 138
Ferns / 141
4 • SPECIES NUMBER, ISLAND AREA, Fruiting Shrubs / 150
AND ISOLATION / 56
Hydrochores: Drifters on the Sea / 161
Equilibrium or Nonequilibrium Species
Anemochores: Drifters on the Wind / 166
Numbers? / 56
vii
8 • ECOLOGICAL AND EVOLUTIONARY SHIFTS Colonization and Extinction
ON CONTINENTAL ISLANDS / 180 Dynamics / 209
Alien Invaders / 181 Coexistence and a Potential Role for
Ecological Shifts in Impoverished Competition / 212
Biotas / 185 Adaptation, Evolution, Conservation / 215
Evolutionary Shifts in Isolated
Appendixes / 217
Populations / 194
References / 248
9 • SYNOPSIS: LESSONS FROM A CONTINENTAL Index / 256
ARCHIPELAGO / 205
The Barkley Sound Scene / 205
Is There an Equilibrium out There? / 206
viii contents
preface
This is a book about a field study that just grew evolutionary shifts are slow, sustained, and per-
and grew; it grew until I was quite sure that, if it haps largely already carried to resolution.
were not written up at this “intermediate” stage, In the early years of the work, the questions
it never would be. I was concerned that the pat- were fairly specific, somewhat pedestrian, and of
terns would dissolve in the fogs of time, and the the snapshot type—for example, how do species
lessons I had learned might slip away unless I numbers increase with island size?—and the
wrote them down without further delay and in- answers were similarly straightforward. As time
terpreted them as best I could while I still had a added dimensionality to the data set in at least
grasp on them. In one sense this is a broad proj- one sense, the dynamics soon overshadowed
ect on the statics and dynamics of island bio- the statics, and the questions became multidi-
geography and the ecology and evolution of a mensional and more complex, eventually frag-
regional biota; in another it is narrowly con- menting into various subplots, minor themes,
strained to the plants of a single archipelago in and taxonomically qualified sidebars. It was be-
British Columbia, Canada. Plants on Islands coming a challenge to keep the islands, the
relates various facets of the classical island bio- years, the plants, and their comings and goings
geography literature to geologically recent is- distinct; clearly it was time for the grand syn-
lands, a few thousands of years old, that house thesis. While hitherto a few small vignettes
everyday, typical mainland plants (no glam- have emerged in print, the book is nearly all
orous endemics here). What does come into fo- composed of material with no prior publication
cus, I hope, is a scene in which the island plant history; I have greatly appreciated the luxury of
lists are continually changing with time, gener- being able to wait to write it until a fairly com-
ating a turnover of species fueled by rapid colo- plete story could be assembled.
nization rates tempered by the equally rapid ex- The study grew from an initial interest in
tinction of local, small and patchy populations. the ecology of foraging auks (Aves: Alcidae) in
In a way, this lively, dynamical picture is quite the Pacific Northwest. That interest led me first
the opposite of what happens on remote (and to the islands and marine environments of
biogeographically quiescent) oceanic islands; Barkley Sound, British Columbia, and then to
there changes in the biotic roster happen only considering the islands’ land birds as potential
rarely, and the processes driving ecological and subjects for biogeographic work. Eventually,
ix