ing from more drastic land transformations. Where landscapes have been
denuded through inadequate land use or degraded agricultural areas have been
abandoned, revegetation with agroforestry practices can promote biodiversity
conservation.
It can be rightly argued that all agroforestry systems, however forest-like
they may appear, ultimately displace natural ecosystems, either through out-
right clearing and replanting with crop and tree species or through variable
degrees of “domestication” of the original landscape and ecosystem. However,
when compared with other nonforest land use options, such as modern, inten-
sively managed monocultures of coffee, rubber, or oil palm with little genetic
and structural diversity, or even vast stretches of pasture or annual crops with
little tree cover or none at all, agroforestry systems may offer a greater poten-
tial as auxiliary tools for biodiversity conservation strategies while attaining
production goals.
What forms the basis for the expectation that agroforestry practices can
help conserve biodiversity in human-dominated landscapes? Can this expecta-
tion be empirically justified? Answering these questions is a central goal of this
book. Here, we present three hypotheses of how agroforestry could contribute
to biodiversity conservation in human-dominated tropical landscapes. These
hypotheses are explored in detail in the chapters and evaluated in the Conclu-
sion at the end of this book.
The Agroforestry-Deforestation Hypothesis
Agroforestry can help reduce pressure to deforest additional land for
agriculture if adopted as an alternative to more extensive and less sus-
tainable land use practices, or it can help the local population cope
with limited availability of forest land and resources, for example near
effectively protected parks.This hypothesis is based largely on the assumption that certain agroforestry
practices, if profitable and sustainable, may occupy the available labor force
and satisfy the needs of a given population on a smaller land area than exten-
sive land use practices such as cattle pasture, thereby reducing the need to
deforest additional land. Extensive land use practices are common in agricul-
tural frontier regions because of the often low land prices and poor market
access. More intensive agricultural practices, where economically viable, may
be able to bring area needs per household or unit of produce lower than agro-
forestry practices can but may expose farmers to unacceptable economic and
ecological risks (Johns 1999). Furthermore, agroforestry practices may be
more sustainable and therefore allow the use of deforested plots over a longer
time period than alternative land use methods, such as pure annual cropping
(which may rapidly degrade the soil, especially on erosion-prone and low-
Introduction: Agroforestry in Biodiversity Conservation in Tropical Landscapes 7