Data from: The mutualism-antagonism continuum in Neotropical palm-frugivore interactions: from interaction outcomes to ecosystem dynamics

Frugivory, i.e. feeding on fruits, pulp or seeds by animals, is usually
considered a mutualism when interactions involve seed dispersal, and an
antagonism when it results in the predation and destruction of seeds.
Nevertheless, most frugivory interactions involve both benefits and
disadvantages for plants, and the net interaction outcomes thus tend to
vary along a continuum from mutualism to antagonism. Quantifying outcome
variation is challenging and the ecological contribution of frugivorous
animals to plant demography thus remains little explored. This is
particularly true for interactions in which animals do not ingest entire
fruits, i.e. in seed-eating and pulp-eating. Here, we provide a
comprehensive review of Neotropical palm–frugivore interactions, with a
focus on how frugivore consumption behaviour (i.e. digestive processing,
caching behaviour and fruit-handling ability) and feeding types
(fruit-eating, pulp-eating and seed-eating) influence interaction outcomes
at different demographic stages of palms. We compiled a total of 1043
species-level palm–frugivore interaction records that explicitly captured
information on which parts of palm fruits are eaten by animals. These
records showed consumption of fruits of 106 Neotropical palm species by
273 vertebrate species, especially birds (50%) and mammals (45%), but also
fish (3%) and reptiles (2%). Fruit-eating involved all four taxonomic
vertebrate classes whereas seed-eating and pulp-eating were only observed
among birds and mammals. Most fruit-eating interactions (77%) resulted in
positive interaction outcomes for plants (e.g. gut-passed seeds are viable
or seeds are successfully dispersed), regardless of the digestive
processing type of vertebrate consumers (seed defecation versus
regurgitation). The majority of pulp-eating interactions (91%) also
resulted in positive interaction outcomes, for instance via pulp removal
that promoted seed germination or via dispersal of intact palm seeds by
external transport, especially if animals have a good fruit-handling
ability (e.g. primates, and some parrots). By contrast, seed-eating
interactions mostly resulted in dual outcomes (60%), where interactions
had both negative effects on seed survival and positive outcomes through
seed caching and external (non-digestive) seed dispersal. A detailed
synthesis of available field studies with qualitative and quantitative
information provided evidence that 12 families and 27 species of mammals
and birds are predominantly on the mutualistic side of the continuum
whereas five mammalian families, six mammal and one reptile species are on
the antagonistic side. The synthesis also revealed that most species can
act as partial mutualists, even if they are typically considered
antagonists. Our review demonstrates how different consumption behaviours
and feeding types of vertebrate fruit consumers can influence seed
dispersal and regeneration of palms, and thus ultimately affect the
structure and functioning of tropical ecosystems. Variation in feeding
types of animal consumers will influence ecosystem dynamics via effects on
plant population dynamics and differences in long-distance seed dispersal,
and may subsequently affect ecosystem functions such as carbon storage.
The quantification of intra- and inter-specific variation in outcomes of
plant–frugivore interactions – and their positive and negative effects on
the seed-to-seedling transition of animal-dispersed plants – should be a
key research focus to understand better the mutualism–antagonism continuum
and its importance for ecosystem dynamics.