Plants on Islands: Diversity and Dynamics on a Continental Archipelago by Martin L. Cody

2007·1.4 MB·English

by  Review By: Allan A Schoenherr

Madrono, Vol. 54, No. 1, pp. 99-100, 2007
REVIEW
Plants on Islands: Diversity and Dynamics on The rest of the book is specifically about the
a ContinentalArchipelago. By MARTIN L. CODY. islands ofBarkley Sound. Chapter2 is an excellent
2006. University of California Press, Berkeley, introduction to the geography, geology, history,
CA. 315 pp. Hard Cover $49.95. ISBN 978- climate, and general ecology of the region. Of
052024729-1. particular interest is his discussion ofthe flora and
vegetation of the "Coastal Coniferous Forest."
Barkley Sound is a large embayment on the This community, distributed from southeastern
west side ofVancouver Island, British Columbia. Alaska to northern California, is also referred to
IBtasceodntoaninasfioevlderstu2d0y0thiastlaenxdtsenodfedvanreiaorulsy 2s5izyesr., bMyanmyanpyeoapultehotrhsinaksifthtehe"sTeefmopreesrtas,tewhRiacihnfoirnecsltu,d"e
Martin Cody of UCLA has compiled an enor- the largest terrestrial organisms on earth, as one of
mous data set on diversity and dynamics ofsome North America's treasures. Readers who may not
300 species of plants that inhabit the islands of be familiar with wet coastal forests, will gain an
Barkley Sound. In this book, these data have appreciation for the diversity and significance of
been exploited in every imaginable way in order this community to the biota ofthe world.
to test the concepts and theories of island Chapters 4 through 8 deal specifically with the
biogeography. Four appendices at the back of islands of Barkley Sound. Each chapter analyzes
the book include lists of plant species, bird tthhee pMla/ntWs omnodtheelseoifslaMnadscAfrrtohmura paernsdpecWtiilvseono.f
species, and a gazetteer of Islands.
In his introduction, Cody reviews the history Chapter 4 is about species numbers, island size,
and isolation. Chapter 5 on "nestedness and
ofisland biogeographic studies beginningwith Sir
assembly rules" analyzes the distribution of
Joseph Hooker's presentation in 1846 to the
species within different habitats. Chapter 6 deals
Linnaean Society on the flora of the Galapagos
specifically with "turnover rates," in which the
Islands. Using Hooker's initial contributions to balance between colonization and extinction on
the understanding of islands, Cody lays out the
framework for his studies on the plants of the these islands is described. Chapter 7 is about the
various mechanisms and dynamics of dispersal
islands in Barkley Sound, pointing out that these responsible for the species on these islands. It is
are continental islands, not oceanic islands, hence
particularly interesting in its documentation that,
he will say little about endemism, radiations, and over time, dispersal capacity on the islands
relicts. In the introduction, he also states that this becomes reduced in wind-dispersed members of
book, "...is in no way intended to be a review, or the Asteraceae. Chapter 8 is about the impact and
overview, of island biogeography, ecology, or evolution ofnon-nativespecies. Hepoints out that
evolution, or of island plant biology." He then "weedyaliens" colonizeprimarilyedgehabitats or
lists his ''personal favorites" of all the literature disturbance sites, and they evolve rapidly, typical-
he deems relevant to the science ofisland biology, ly losing significant dispersal capacity over a peri-
a list in itself that should be useful to anyone od of decades. Here, Cody is able to generalize
interested in the biogeography of island plants. about theinfluenceofnon-nativecolonizationson
Having made that disclaimer in the introduc- depauperate island floras. Also in Chapter 8 he
tion, Cody then goes on, particularly in Chapter 3, analyzes data that show evolutionary shifts in two
to write an excellent overview of the theory, species of animals, deer mice and banana slugs.
concepts, and analytical tools ofisland biogeogra- Deer mice on Willis Island were almost 20%
phy, emphasizing chiefly the aspects of coloniza- heavierthan thoseon themainland, anexampleof
tion and extinction dynamics of continental gigantism that often is demonstrated by rodents
islands. He pays tribute to the work of R. H. on islands in other parts of the world. The
MacArthur and E. O. Wilson, who in the 1960s extensive discussion of evolution in spotting
laidouttheprinciplesofthe "equilibriumtheoryof patternsofbananaslugsisparticularlyinteresting.
island biogeography." This well know theory, Banana slugs, relict species which are virtually
referredto byCodyasthe"MAVmodel," balances unable to cross seawater barriers, have evolved on
immigration and extinctions rates as a function of these islands for about 10,000 yr. During that
cnluemarbleyrdeosfcrspiebceisesh.oWwitthheaMseAriVesmoofdgerlapahpsp,liCesodtyo tinimaes,siotcaipaptieoanrswitthahtotpheenunhsapboittattesdwmhoerrpehstheevyoltveendd
islands of various sizes and distances from the to be more suitably adapted to warm, dry
mainland. This chapter, by itself, is a valuable conditions. In these five chapters, loaded with
contributiontotheliteratureaboutislandplants. It graphs and statistics, Martin Cody illustrates how
is illustrated with graphs and data, all ofwhich are a scientist can exploit his data. He does it
eloquently explained, and his use of statistics will wonderfully, never failing to explain how the data
not overwhelm the reader. fit the concepts he is analyzing.
MADRONO
100 [Vol. 54
Chapter 9, the final chapter, is a synopsis the islands in Barkley Sound and applies the data
subtitled "Lessons from a Continental Archipel- to processes of evolution and biogeography as
ago." In this chapter, Cody summarizes what he they apply to continental islands in general.
learned about the evolutionary and biogeograph- Furthermore, it is an important resource that
ic picture of the islands in Barkley Sound. Once characterizes one of North America's significant
again, he generalizes about the relevance to plant communities, the moist coastal coniferous
biogeographic theories, particularly with respect forest of the Pacific Northwest. Every biologist
to the MAV model. He talks about phenomena withaninterestinislandsorthespectacularforests
that fit his expectations and those that didn't. He ofthe Pacific Northwest should own this book.
finishes up by emphasizing what seemed most
important to biogeographic theory ofislands.
—
This book is an invaluable addition to bi- Allan A. Schoenherr. Professor ofEcology, Emeritus
ological literature. Based on nearly a quarter- Fullerton College, 321 E. Chapman Avenue, Fullerton,
century of research, it clearly depicts the flora of CA 92832. [email protected].