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documented a decreased diversity of nectarivorous bats [83] and hawkmoths [84]
in small fragments. However, empirical evidence to determine which pollination-
related traits and plant-pollinator mutualisms are particularly susceptible to habi-
tat disturbance is still scarce [28]. Our results suggest that the reduced number of
tree species and individuals pollinated by bats and Sphingids in fragments and the
absence of fly-, bird-, and non-flying-mammal-pollinated trees, together with the
changes in floral traits and sexual systems, may be a higher order effect promoted
by habitat fragmentation.
Implications of Reduced Functional Diversity
The reduced reproductive functional diversity documented in our study landscape's
fragments resulted primarily from the lack or skewed representation of some pol-
lination systems, floral types, and floral size categories in terms of both species and
individual (see Table 3). In other words, tree assemblages in this habitat appear
to carry a narrower range of floral traits and pollination systems in comparison
to patches of forest interior, particularly for pollinators such as mammals and
hawkmoths (reduced support capacity). Regardless the underlying mechanism,
this narrow range may (1) promote the collapse of pollinator populations; (2)
restrict the ecological range of plant and animal groups able to colonize remain-
ing patches of forest or even turn fragments into sink habitats for both plants and
their pollinators; and (3) alter the course of natural regeneration or the dynamics
of forest fragments toward the establishment of impoverished assemblages in terns
of species richness, ecological composition and trophic structure.
Unfortunately, few studies have addressed shifts on the diversity of plant re-
productive traits in human-disturbed habitats, especially those traits associated
with plant-pollinator interactions [1], [72]. Studies linking these shifts to func-
tional diversity are even more scarce [1], [2], despite the fact that pollination pro-
cesses influence biodiversity maintenance and ecosystem functioning. Fontaine et
al. [2], for example, argued that even simple structured plant-pollinator commu-
nities may have their persistence threatened due to reduced functional diversity,
thereby suggesting that functional diversity of pollination networks is critical to
avoid biodiversity loss.
In summary, it is reasonable to propose as a working hypothesis that the per-
sistence of biodiversity and consequently the long-term conservation value of iso-
lated tropical forest fragments may be negatively affected by reduced functional
diversity to such an extent yet not anticipated by conservation biologists. Collec-
tively, the proliferation of pioneer species, extirpation of shade-tolerant trees, and
reduced functional diversity have the potential to disrupt some trophic interac-
tions [e.g. 85]; even landscapes such as ours that were fragmented long ago and
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