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individuals within 50 categories of reproductive traits (distributed in four
major classes: pollination systems, floral biology, sexual systems, and reproduc-
tive systems) in 10 fragments and 10 tracts of forest interior (control plots). As
hypothesized, populations in fragments and control plots differed substantial-
ly in the representation of the four major classes of reproductive traits (more
than 50% of the categories investigated). The most conspicuous differences
were the lack of three pollination systems in fragments-pollination by birds,
flies and non-flying mammals-and that fragments had a higher frequency of
both species and individuals pollinated by generalist vectors. Hermaphroditic
species predominate in both habitats, although their relative abundances were
higher in fragments. On the contrary, self-incompatible species were under-
represented in fragments. Moreover, fragments showed lower functional diver-
sity (H' scores) for pollination systems (−30.3%), floral types (−23.6%), and
floral sizes (−20.8%) in comparison to control plots. In contrast to the over-
whelming effect of fragmentation, patch and landscape metrics such as patch
size and forest cover played a minor role on the frequency of traits. Our re-
sults suggest that habitat fragmentation promotes a marked shift in the rela-
tive abundance of tree reproductive traits and greatly reduces the functional
diversity of tree assemblages in fragmented landscapes.
Introduction
Functional diversity can be defined as a variety of life-history traits presented
by an assemblage of organisms [1], [2] and it has been postulated to be critical
for the maintenance of ecosystem processes and properties [3]. For example,
previous empirical work has suggested that ecosystems with a high diversity of
functional traits have greater efficiency of water, nutrient, and light use, as well
as higher productivity [3], [4]. In addition, they may also be more resilient [5]
and resistant to biological invasions and to biodiversity loss [6], [7]. Neverthe-
less, most studies on functional diversity in plant communities have focused
on the importance of traits associated with plant physiology. Consequently, we
know little regarding the functional diversity of other traits that also affect both
community structure and ecosystem functioning, such as those related to plant-
animal interactions [1], [2].
Habitat loss and fragmentation (hereafter habitat fragmentation) have been
shown to dramatically alter tree communities in tropical forests [8]-[12]. Frag-
ments usually exhibit reduced species richness and diversity, particularly near
edges. This reduction in species diversity is due in large part to loss of species
that are “shade-tolerant” [8], [12], [13], restricted to the forest understory [10],
have large-seeds [14], [15], or are dispersed by vertebrates [12], [16]-[19].
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