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Fruit Removal (fruit + removal)

Distribution by Scientific Domains

Life Sciences	87%

Selected Abstracts

Vertebrate Fruit Removal and Ant Seed Dispersal in the Neotropical Ginger Renealmia alpinia (Zingiberaceae),

BIOTROPICA, Issue 2 2009
Carlos García-Robledo
ABSTRACT Plants frequently display fruit characteristics that support multiple seed-dispersal syndromes. These ambiguous characteristics may reflect the fact that seed dispersal is usually a complex process involving multiple dispersers. This is the case for the Neotropical ginger Renealmia alpinia (Zingiberaceae). It was originally suggested that the aromatic fruits of R. alpinia located at the base of the plant are adapted for terrestrial mammal seed dispersal. However, the dark-purple coloration of the fruits and bright orange aril surrounding the seeds suggest that birds may play a role in R. alpinia seed dispersal. At La Selva Biological Station, Costa Rica, we used camera traps to record vertebrate visits to infructescences of R. alpinia. Most visitors were toucans and aracaris (Ramphastidae). However fruits were also removed by terrestrial mammals (coatis and armadillos). In addition to vertebrate fruit removal, some of the fruits dehisce and the seeds that fall on the ground are dispersed by ants. Fruitfall traps showed that 77 percent of fruits are removed by vertebrates. However, 15 percent of fruits fall to the base of parent plants to be potentially dispersed by ants. Experiments using a laboratory ant colony showed that ants are effective seed dispersers of R. alpinia. Ant seed manipulation increased germination success and reduced time to germination. In conclusion, primary seed dispersal in the Neotropical ginger R. alpinia is mostly performed by birds, additionally ants are effective dispersers at short distances. Seed dispersal in R. alpinia is a complex process involving a diverse array of dispersal agents. RESUMEN Los frutos de algunas plantas presentan características que se ajustan a más de un síndrome de dispersión. Es posible que estas características ambiguas reflejen el hecho de que la dispersión de semillas es usualmente un proceso complejo que involucra múltiples organismos dispersores. Ese es el caso de la Zingiberaceae Neotropical Renealmia alpinia. Originalmente se sugirió que los frutos aromáticos y la posición basal de las infrutescencias de R. alpinia son adaptaciones para la dispersión por mamíferos terrestres. Sin embargo, el color morado oscuro del exocarpo y el color anaranjado de los arilos en los frutos maduros sugieren que las aves pueden jugar un papel importante en la dispersión de semillas de R. alpinia. En la estación Biológica La Selva, Costa Rica, usamos cámaras trampa para registrar las visitas por invertebrados a las infrutescencias de R. alpinia. La mayoría de las visitas fueron por tucanes y arasaríes (Ramphastidae). La dispersión de semillas en R. alpinia puede ser aún más compleja pues parte de los frutos maduros liberan semillas en la base de la planta, las cuales son dispersadas por hormigas. Trampas de frutos registraron 77% de los frutos removidos por vertebrados. Sin embargo las semillas de 15% de los frutos cayeron en el suelo para ser potencialmente dispersadas por hormigas. Experimentos en laboratorio demostraron que las hormigas son dispersores efectivos de R. alpinia. Semillas manipuladas por hormigas germinaron en mayor proporción y presentaron una reducción en el tiempo de germinación. En conclusión, los frutos de R. alpinia son principalmente dispersados por aves. Adicionalmente, las hormigas son eficaces dispersoras de semillas a cortas distancias. La dispersión de semillas en R. alpinia es un proceso complejo que involucra un diverso gremio de agentes dispersores. [source]

Context-dependency of a complex fruit,frugivore mutualism: temporal variation in crop size and neighborhood effects

OIKOS, Issue 3 2010
Soumya Prasad
The quantity of fruit consumed by dispersers is highly variable among individuals within plant populations. The outcome of such selection operated by frugivores has been examined mostly with respect to changing spatial contexts. The influence of varying temporal contexts on frugivore choice, and their possible demographic and evolutionary consequences is poorly understood. We examined if temporal variation in fruit availability across a hierarchy of nested temporal levels (interannual, intraseasonal, 120 h, 24 h) altered frugivore choice for a complex seed dispersal system in dry tropical forests of southern India. The interactions between Phyllanthus emblica and its primary disperser (ruminants) was mediated by another frugivore (a primate), which made large quantities of fruit available on the ground to ruminants. The direction and strength of crop size and neighborhood effects on this interaction varied with changing temporal contexts. Fruit availability was higher in the first of the two study years, and at the start of the season in both years. Fruit persistence on trees, determined by primate foraging, was influenced by crop size and conspecific neighborhood densities only in the high fruit availability year. Fruit removal by ruminants was influenced by crop size in both years and neighborhood densities only in the high availability year. In both years, these effects were stronger at the start of the season. Intraseasonal reduction in fruit availability diminished inequalities in fruit removal by ruminants and the influence of crop size and fruiting neighborhoods. All trees were not equally attractive to frugivores in a P. emblica population at all points of time. Temporal asymmetry in frugivore-mediated selection could reduce potential for co-evolution between frugivores and plants by diluting selective pressures. Inter-dependencies formed between disparate animal consumers can add additional levels of complexity to plant,frugivore mutualistic networks and have potential reproductive consequences for specific individuals within populations. [source]

Fragmentation, habitat composition and the dispersal/predation balance in interactions between the Mediterranean myrtle and avian frugivores

ECOGRAPHY, Issue 1 2010
Juan P. González-Varo
Human-induced fragmentation and disturbance of natural habitats can shift abundance and composition of frugivore assemblages, which may alter patterns of frugivory and seed dispersal. However, despite their relevance to the functioning of ecosystems, plant-frugivore interactions in fragmented areas have been to date poorly studied. I investigated spatial variation of avian frugivore assemblages and fruit removal by dispersers and predators from Mediterranean myrtle shrubs (Myrtus communis) in relation to the degree of fragmentation and habitat features of nine woodland patches (72 plants). The study was conducted within the chronically fragmented landscape of the Guadalquivir Valley (SW Spain), characterized by ~1% of woodland cover. Results showed that the abundance and composition of the disperser guild was not affected by fragmentation, habitat features or geographical location. However, individual species and groups of resident/migrant birds responded differently: whereas resident dispersers were more abundant in large patches, wintering dispersers were more abundant in fruit-rich patches. Predator abundances were similar between patches, although the guild composition shifted with fragmentation. The proportion of myrtle fruits consumed by dispersers and predators varied greatly between patches, but did not depend on bird abundances. The geographical location of patches determined the presence or absence of interactions between myrtles and seed predators (six predated and three non-predated patches), a fact that greatly influenced fruit dispersal success. Moreover, predation rates were lower (and dispersal rates higher) in large patches with fruit-poor heterospecific environments (i.e. dominated by myrtle). Predator satiation and a higher preference for heterospecific fruits by dispersers may explain these patterns. These results show that 1) the frugivore assemblage in warm Mediterranean lowlands is mostly composed of fragmentation-tolerant species that respond differently to landscape changes; and 2) that the feeding behaviour of both dispersers and predators influenced by local fruit availability may be of great importance for interpreting patterns of frugivory throughout the study area. [source]

Is there limiting similarity in the phenology of fleshy fruits?

JOURNAL OF VEGETATION SCIENCE, Issue 6 2005
K.C. Burns
Abstract Question: Is there evidence for limiting similarity in the timing of fruit production by a bird-dispersed plant community? Is the rate of fruit removal in each plant species inversely related to fruit availability in other species? Can simple measurements of fruit phenologies (i.e. temporal changes in fruit availability) obscure important fruit attributes that influence their removal by birds? Location: Vancouver Island, British Columbia, Canada. Methods: Periods of fruit availability were measured in ten woody angiosperm species for two years. In the second year, the fate of individual fruits was quantified to disentangle dates of fruit maturation, removal and mortality from measurements of availability. Results: Null model analyses of fruit availability distributions showed no evidence for limiting similarity. However, fruit removal rates of most plant species were correlated with their relative abundance in the community, indicating fruits were removed more rapidly when other fruits were less abundant. Species with similar periods of fruit availability often had different dates of fruit maturation, rates of fruit removal and fruit persistence times, indicating fruit availability measurements can obscure important bird-fruit interactions. Conclusions: Competition for dispersers appears to occur. However, it has not resulted in limiting similarity in fruit availability distributions. A likely explanation for this discrepancy is that fruit availability distributions often confound several important fruit attributes that can independently influence fruit removal by birds. [source]

Context-dependency of a complex fruit,frugivore mutualism: temporal variation in crop size and neighborhood effects

Linking frugivore activity to early recruitment of a bird dispersed tree, Eugenia umbelliflora (Myrtaceae) in the Atlantic rainforest

AUSTRAL ECOLOGY, Issue 3 2009
MARINA CORRÊA CÔRTES
Abstract Seed dispersal by animals is a complex process involving several distinct stages: fruit removal by frugivores, seed delivery in different microhabitats, seed germination, seedling establishment, and adult recruitment. Nevertheless, studies conducted until now have provided scarce information concerning the sequence of stages in a plant's life cycle in its entirety. The main objective of this study was to evaluate the immediate consequences of frugivore activity for Eugenia umbelliflora (Myrtaceae) early recruitment by measuring the relative importance of each fruit-eating bird species on the establishment of new seedlings in scrub and low restinga vegetation in the Atlantic rainforest, Brazil. We conducted focal tree observations on E. umbelliflora trees recording birds' feeding behaviour and post-feeding movements. We also recorded the fate of dispersed seeds in scrub and low restinga vegetation. We recorded 17 bird species interacting with fruits in 55 h of observation. Only 30% of the handled fruits were successfully removed. From 108 post flight movements of exit from the fruiting trees, 30.6% were to scrub and 69.4% to low restinga forest. Proportion of seed germination was higher in low restinga than in the scrub vegetation. Incorporating the probabilities of seeds' removal, deposition, and germination in both sites, we found that the relative importance of each frugivorous bird as seed dispersers varies largely among species. Turdus amaurochalinus and Turdus rufiventris were the best dispersers, together representing almost 12% probability of seed germination following removal. Our results show the importance of assessing the overall consequence of seed dispersal within the framework of disperser effectiveness, providing a more comprehensive and realistic evaluation of the relative importance of different seed dispersers on plant population dynamics. [source]

Petals may act as a reward: myrmecochory in shrubby Darwinia species of south-eastern Australia

AUSTRAL ECOLOGY, Issue 3 2009
TONY D. AULD
Abstract The removal rates of fruits (the diaspore) were assessed in exclusion experiments in three shrubby species of Darwinia, endemic to the Sydney Basin of south-eastern Australia. There was a clear pattern of fruit removal in just a few days by small species of ants from the genera Iridomyrmex, Crematogaster and Pheidole. When only ants had access to fruits an average of 41% of fruits were removed, whereas when only vertebrates had access an average of 13% of fruits were removed. There was some variation in the number of fruits removed both between species and within species across study sites or annual seed crops. When ants had access to seeds this variation in removal amounted to 10,80% over 1,4 days. Uniquely in Darwinia, it is the old petals (which remain attached to the fruit) that are attractive to the ants, rather than a specific lipid body. This likely represents a case of successful ecological fitting by Darwinia to take advantage of the widespread presence of myrmecochory in the Australian flora. [source]