stream flow, and vertebrate population data show that
warming effects are already being felt abiotically and
biotically in Monteverde (Pounds et al. 1999).
Deforestation has broken what was once an inter-
connected chain of highland forests in Costa Rica into
isolated habitats (Fig. 12.3). The Monteverde Reserve
Complex remains one of the country's largest intact
highland forests, but it is still isolated from other high-
land forests (Fig. 12.1; see also Fig. 1.4). As genetic
diversity in many species diminishes in Monteverde,
other unconnected forests can no longer replenish it
or provide colonists to reinforce small populations or
reestablish locally extinct species. The same factors
play out on a smaller spatial scale within Monteverde,
where the landscape has become increasingly trans-
formed into unconnected woodlots surrounded by
pastures, roads, gardens, and houses (Fig. 12.4; see also
Fig. 1.7). Each forest patch can support fewer individu-
als and species than it would have if it were part of a
continuous forest, so diversity over the entire area di-
minishes (Saunders et al. 1991). Forest fragmentation
is also likely to change the ecological dynamics of
mixed-species flocks of birds and the evolutionary
dynamics of guilds of competing species.
The relatively small amount of research directed
specifically toward conservation biology in Monte-
verde has mainly addressed questions at the level of
landscapes. Deforestation has been much more severe
on the Pacific slope below Monteverde than on the
Atlantic side, and it has created a patchwork of for-
est fragments (Fig. 12.4). Neighboring forest patches
turn out to be unexpectedly distinctive in terms of
plant species composition (see Guindon, "Importance
of Pacific Slope Forest," p. 435). Because animal spe-
cies differ in the way that they respond to discon-
tinuities in habitat structure, the forest fragments also
have distinctive animal communities. Two habitat
patches that are connected from the perspective of one
species may be isolated for another species. Emerald
Toucanets and Resplendent Quetzals are similar in size
and diet, yet the former easily cross open areas and are
found in most forest fragments, regardless of their iso-
lation; the latter occur only in patches near extant
forest. Alarmingly, more than half of the tree species
found in certain Pacific slope forest fragments do not
occur within protected areas such as the MCFP. A sub-
stantial proportion of the individual trees and tree spe-
cies in forest remnants are members of the Lauraceae,
and they depend mainly on five bird species for dis-
persal of their seeds (Wheelwright 1991; see Guindon,
"Importance of Pacific Slope Forest," pp. 435-437). The
elimination of either set of "keystone species" would
have disproportionate effects on plant and animal com-
munities of lower montane forests (Guindon 1996).
The potential asymmetry in dispersal ability of dif-
ferent animal mutualists raises an unexplored but po-
tentially important set of questions. An overwhelming
proportion of plant species in Monteverde (and in tropi-
cal forests generally) depend on animals for pollination
and seed dispersal (see Chap. 8, Plant-Animal Interac-
Figure12.3. Logging trucks transport primary forest logs from forest to market. Photograph by Robert Timm.
426 Conservation Biology