Scope of the Book and Key Contributions 7regions because these models place too little
emphasis on propagule limitation and facilitation.
Nonetheless, they propose that with refinements,
and with the addition of quantitative models of
dispersal, a temperate model of succession from
the 1970s (the nucleation model) may accurately
explain early patterns of succession in tropical
pastures.
Chazdon (Chapter 23) provides a thorough
introduction to and review of succession, with a
focus on secondary forests. She applies the stages
of succession in the tropics developed by Oliver
and Larson (1990) for temperate forests: stand
initiation, stem exclusion, understory reinitiation,
and old-growth phases. This framework is impor-
tant because it unites conceptual patterns of
succession in the tropics with those found in
temperate forests. Chazdon questions the notion
that a stable climax would ever be reached, thus
forcing us “to view all forests as points along a
successional continuum.”
Denslow and DeWalt (Chapter 24) examine
four likely hypotheses to explain how continental
tropical forests resist invasion. Using recently
published studies, they conclude that high func-
tional grou pdiversity, high rates of com petitive
exclusion, and high pest loads may all confer
resistance to exotic invasion. Contrary to con-
ventional wisdom, however, high species diversity
alone is unlikely to deter invasion. The authors
emphasize that the data to test these hypothe-
ses are still relatively weak, and they provide a
strategy for future research on this important
topic.TROPICAL FOREST CONSERVATION
The conservation of tropical forests can be
promoted by demonstrating their direct value in
terms of human services. In this section, Kursar
et al. (Chapter 25) outline how basic research
can guide bioprospecting, and thus promote trop-
ical forest conservation. The authors show how
knowledge of plant species and life-history traits
can increase the probability of finding novel
active secondary compounds for drug discovery.
This exciting approach has resulted in technology
transfer, tropical forest conservation, and advance
in combating some of the most devastating
human diseases of our time.
Corlett and Primack (Chapter 26) take a global
perspective on tropical forest conservation and
conclude that there are “many rainforests” and
“many threats” and that the conservation of the
world’s richest ecosystems needs to be a global
effort yet reflect clear regional differences. They
outline how threats vary among the world’s major
forests: Asia, Africa, Madagascar, New Guinea,
Central and South America, Australia, and island
rainforests. They conclude that “the single most
important strategy for protecting intact rainforest
communities is to establish – and effectively
manage – protected areas.”
While Corlett and Primack took a worldwide
focus, Laurance (Chapter 27) hones in on threats
and promise for conservation in the Amazon. The
outlook is sometimes bleak; in a reference to
the biblical book of Revelation, Laurance argues
that the four horsemen of the future tropical apoc-
alypse will be uncontrolled agriculture, logging,
wildfires, and widespread fragmentation. Annual
deforestation is staggering and additional threats
include burgeoning immigration and massive eco-
nomic development. Thankfully, Laurance finds a
silver lining in the figurative dark cloud hanging
over tropical forest conservation. He suggests that
this is also a time of “unparalleled opportunity
for conservation” due to expanding networks of
reserves, corridors, and other conservation units.
Putz and Zuidema (Chapter 28) argue passion-
ately that ecologists need to examine conserva-
tion within a much broader social, economic,
and political context. They suggest that in
many instances (though not all) “expertocratic
approaches,” such as creating a system of walled-
off protected reserves, are inappropriate to local,
cultural, and political realities. The authors call
for expanded research into processes that promote
and maintain biodiversity in human-altered land-
scapes that vary in size from small fragments to
large plantations. Are we as ecologists seques-
tering ourselvesaway in pristine forests while
secondary forests are starved of inquiry?
Overall, we believe that these chapters serve to
not only synthesize the current state of knowledge
on the ecology of tropical forest communities, but
they also point out some of the long-standing but