Publication Date:
2024-06-04
Description:
Aim: The efficiency of animal-mediated seed dispersal is threatened by the decline of
animal populations, especially in tropical forests. We hypothesise that large-seeded
plants with animal-mediated dispersal tend to have limited geographic ranges and
face an increased risk of extinction due to the potential decline in seed dispersal by
large-bodied fruit-eating and seed-dispersing animals (frugivores).
Location: Atlantic Forest, Brazil, South America.
Taxon: Angiosperms.
Methods: First, we collected dispersal-related traits (dispersal syndrome, fruit size,
and seed size), growth form (tree, climber, and other) and preferred vegetation type
(open and closed) data for 1052 Atlantic Forest plant species. Next, we integrated
these with occurrence records, extinction risk assessments, and phylogenetic trees.
Finally, we performed phylogenetic generalised least squares regressions to test the
direct and interactive effects of dispersal-related traits and vegetation type on geographical range size.
Results: Large-seeded species had smaller range sizes than small-seeded species, but
only for species with animal-mediated dispersal, not for those dispersed by abiotic
mechanisms. However, plants with abiotic dispersal had overall smaller range sizes
than plants with animal-mediated dispersal. Furthermore, we found that species restricted to forests had smaller ranges than those occurring in open or mixed vegetation. Finally, at least 29% of the Atlantic Forest flora is threatened by extinction, but
this was not related to plant dispersal syndromes.
Main Conclusions: Large-seeded plants with animal-mediated dispersal may be suffering from dispersal limitation, potentially due to past and ongoing defaunation of
large-bodied frugivores, leading to small range sizes. Other factors, such as deforestation and fragmentation, will probably modulate the effects of dispersal on range size,
and ultimately extinction. Our study sheds light on the relationship between plant
traits, mutualistic interactions, and distribution that are key to the functioning of
tropical forests.
Keywords:
defaunation
;
extinction risk
;
frugivory
;
phylogeny
;
range size
;
seed dispersal
;
tropical forest
Repository Name:
National Museum of Natural History, Netherlands
Type:
info:eu-repo/semantics/article
Format:
application/pdf
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