12.1. Richness, Endemism,
and Biodiversity
Monteverde's diverse habitats—forest canopies dense
with epiphytes, deeply shaded understories and bright
tangled light gaps, networks of streams, diverse soil
types—support a vast number of species of animals,
plants, fungi, and microbes, far more than one would
find in virtually any temperate zone site of compa-
rable area. Nowhere on earth are there as many species
of orchids as in Monteverde (see Atwood, "Orchids,"
pp. 74-75). Beta species richness, the accumulation
of new species as one moves between adjacent habi-
tats, is extremely high, particularly on the Pacific slope
(see Chap. 3, Plants).
Biodiversity is more than just a species tally, how-
ever. The concept incorporates the ways that species
interact with one another as predators, prey, parasites,
hosts, mutualists, or competitors. Monteverde is also
rich in species interactions and ecosystem processes.
The vast majority of plant species depend on animals
for pollinators or seed dispersal (see Chap. 8, Plant-
Animal Interactions). The interception of wind-driven
cloud moisture along the Continental Divide is one
of several distinctive ecosystem processes that occur
in Monteverde and in other high-elevation habitats,
but not in the lowland tropics. (Doumenge et al. 1994;
see Chap. 9, Ecosystem Ecology). Even habitats that
have been extensively modified by humans, such
as pastures and gardens, are biologically diverse in
Monteverde. Biodiversity in the broadest sense is a
characteristic feature of Monteverde.
Another distinctive feature of Monteverde's bio-
diversity is that most of its species and interactions
occur only in the highlands of Central America, and
many are restricted to the Cordillera de Tilaran. En-
demism is particularly high, and the local extinction
of endemic species has a far greater impact on global
biodiversity than the local extinction of widespread
species. Monteverde also safeguards a disproportion-
ately high percentage of Central America's remaining
forests. Extensive deforestation in the lowlands from
Mexico to Panama has isolated or eliminated most
highland forests in the region (Fig. 12.1; see also Fig.
1.4). These aspects of the biology of Monteverde—the
region's great richness of species, habitats, inter-
actions, and ecosystem functions; its high degree of
endemism; its preservation of Costa Rica's shrinking
forest cover; and its accelerating extinction pres-
sures—are the critical background for understanding
the conservation biology of the region.
Why should we be concerned with protecting bio-
diversity? Biologically rich, intact ecosystems provide
services such as nutrient cycling and the maintenance
of clean water and air (Daily et al. 1997). Ecosystem
processes in Monteverde help sustain ecological com-
munities over a wide area of Costa Rica. Preserving the
genetic diversity of populations and species and the
complexity of interactions among species can also yield
direct economic benefits, many of them still unrecog-
nized. Less easily measured but equally important are
the aesthetic, cultural, and spiritual values we gain by
exploring and protecting our natural heritage (Wilson
1984, Wilson and Peter 1986). The Resplendent Quetzal
exemplifies both the tangible and intangible values of
preserving wildlife, and the challenges we face in ar-
guing convincingly that we must preserve biodiversity
(see Wheelwright, "Enduring Reasons," pp. 432-433).12.2. An Overview of Key Concepts
in Conservation BiologyConservation biology is dedicated to protecting ge-
netic diversity, species and ecosystems by drawing in-
sights and techniques from a variety of disciplines,
particularly the biological sciences—population biol-
ogy, behavior, ecosystem ecology, molecular biology,
genetics, and evolutionary biology—as well as atmo-
spheric chemistry, geology, and other physical sci-
ences; economics, political science, and sociology; and
history, philosophy, and related fields. Conservation
biologists deal with such problems as the evaluation
and maintenance of biodiversity, endangered species
management, the design of nature reserves, restoration
of degraded habitats, environmental ethics, and eco-
logical economics. Specific references in conservation
biology are available in several excellent recent books
(Soule 1986, Primack 1993, Hunter 1996, Meffe and
Carroll 1997, Fiedler and Kareiva 1998) and in such
journals as Conservation Biology, Biological Conser-
vation, and Ecological Applications.
The fundamental threats to biodiversity can be
classified into four general concerns: (1) the scarcity
or loss of certain species; (2) the proliferation of other
species, including pests; (3) the impoverishment of
ecological interactions because of declines or changes
in populations of interacting species; and (4) the dis-
ruption of ecosystem functions such as nutrient cy-
cling or energy flow. Conservation biology is particu-
larly concerned with understanding the factors that
make species rare. In some cases, such as the North
American Passenger Pigeon (Ectopistes migratorius),
populations may fall from staggeringly large num-
bers to extinction in a decade or less. Most threat-
ened species become rare more gradually, however.
A species can be considered rare by any combination
of a variety of criteria: if its population size is very
small, if it has a restricted geographical range, or if it
can exist or reproduce only in a limited subset of habi-420 Conservation Biology