scholarly journals Extremely long-distance seed dispersal by an overfished Amazonian frugivore

2011 ◽  
Vol 278 (1723) ◽  
pp. 3329-3335 ◽  
Author(s):  
Jill T. Anderson ◽  
Tim Nuttle ◽  
Joe S. Saldaña Rojas ◽  
Thomas H. Pendergast ◽  
Alexander S. Flecker
Keyword(s):  
Seed Dispersal ◽  
Mechanistic Model ◽  
Long Distance ◽  
Seed Dispersal Effectiveness ◽  
Colossoma Macropomum ◽  
Seed Retention ◽  
Dispersal Distances ◽  
Viable Seeds ◽  
Almost All ◽  
Dispersal Effectiveness

Throughout Amazonia, overfishing has decimated populations of fruit-eating fishes, especially the large-bodied characid, Colossoma macropomum . During lengthy annual floods, frugivorous fishes enter vast Amazonian floodplains, consume massive quantities of fallen fruits and egest viable seeds. Many tree and liana species are clearly specialized for icthyochory, and seed dispersal by fish may be crucial for the maintenance of Amazonian wetland forests. Unlike frugivorous mammals and birds, little is known about seed dispersal effectiveness of fishes. Extensive mobility of frugivorous fish could result in extremely effective, multi-directional, long-distance seed dispersal. Over three annual flood seasons, we tracked fine-scale movement patterns and habitat use of wild Colossoma , and seed retention in the digestive tracts of captive individuals. Our mechanistic model predicts that Colossoma disperses seeds extremely long distances to favourable habitats. Modelled mean dispersal distances of 337–552 m and maximum of 5495 m are among the longest ever reported. At least 5 per cent of seeds are predicted to disperse 1700–2110 m, farther than dispersal by almost all other frugivores reported in the literature. Additionally, seed dispersal distances increased with fish size, but overfishing has biased Colossoma populations to smaller individuals. Thus, overexploitation probably disrupts an ancient coevolutionary relationship between Colossoma and Amazonian plants.

scholarly journals Long seed dispersal distances by an inquisitive flightless rail ( Gallirallus australis ) are reduced by interaction with humans

2019 ◽  
Vol 6 (8) ◽  
pp. 190397
Author(s):  
Joanna K. Carpenter ◽  
Colin F. J. O'Donnell ◽  
Elena Moltchanova ◽  
Dave Kelly
Keyword(s):  
Seed Dispersal ◽  
Mechanistic Model ◽  
Human Interaction ◽  
Time Data ◽  
Seed Retention ◽  
Function Loss ◽  
The Mean ◽  
Human Use ◽  
Dispersal Distances ◽  
Seed Retention Time

Human presence is becoming increasingly ubiquitous, but the influence this has on the seed dispersal services performed by frugivorous animals is largely unknown. The New Zealand weka ( Gallirallus australis ) is an inquisitive flightless rail that frequently congregates in areas of high human use. Weka are important seed dispersers, yet the seed dispersal services they provide are still poorly understood. We estimated seed dispersal distances of weka for two plant species ( Prumnopitys ferruginea and Elaeocarpus dentatus ) and tested how human interaction affected these dispersal distances. We estimated weka seed dispersal distances by combining GPS data from 39 weka over three sites with weka seed retention time data in a mechanistic model. The mean seed retention times were extremely long (38–125 h). Weka were highly effective dispersers, dispersing 93–96% of seeds away from parent canopies, and 1% of seeds over 1 km. However, we found evidence of a significant human impact on the seed dispersal distances of weka, with birds occupying areas of high human use performing 34.8–40.9% shorter distances than their more remote counterparts. This represents an example of cryptic function loss, where although weka are still present in the ecosystem, their seed dispersal services are impaired by human interaction.

scholarly journals The timing of frugivore‐mediated seed dispersal effectiveness

2018 ◽  
Vol 28 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Juan P. González‐Varo ◽  
Juan M. Arroyo ◽  
Pedro Jordano
Keyword(s):  
Seed Dispersal ◽  
Seed Dispersal Effectiveness ◽  
Dispersal Effectiveness

scholarly journals Animal movement drives variation in seed dispersal distance in a plant–animal network

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182007 ◽  
Author(s):  
E. Rehm ◽  
E. Fricke ◽  
J. Bender ◽  
J. Savidge ◽  
H. Rogers
Keyword(s):  
Seed Dispersal ◽  
Animal Movement ◽  
Bird Species ◽  
Dispersal Distance ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Gut Passage ◽  
Dispersal Distances ◽  
Seed Dispersal Distance ◽  
Passage Times

Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.

Seed dispersal effectiveness by frugivorous birds: Identifying functional equivalent species in bird assemblages

2019 ◽  
Vol 12 (3) ◽  
pp. 103-108
Author(s):  
Facundo Xavier Palacio
Keyword(s):  
Seed Dispersal ◽  
Statistical Significance ◽  
Bird Species ◽  
Kernel Functions ◽  
Bird Conservation ◽  
Frugivorous Birds ◽  
Seed Dispersal Effectiveness ◽  
Bird Assemblages ◽  
Functional Equivalent ◽  
Dispersal Effectiveness

Seed dispersal by birds is a pivotal ecosystem function worldwide; yet, the rapid and ongoing global biodiversity loss poses a major threat to this essential ecosystem service. Seed dispersal effectiveness (SDE) is a key outcome of the interaction, represented by the product of seed dispersal quantity (number of seed dispersed) and quality (probability of recruitment of dispersed seeds). Therefore, identifying functional equivalent species in terms of SDE should become a key issue for bird conservation, since the effects of local extinctions on seed dispersal services may be weakened by remaining equivalent species. However, a method to quantitatively identify functional equivalent species in frugivorous bird assemblages is still lacking. To estimate SDE overlap between seed dispersers and assess whether two species may be functionally equivalent, I apply a novel nonparametric niche overlap index based on kernel functions and null models to test its statistical significance. For each bird species, I account for intraspecific variation in seed dispersal effectiveness to obtain a distribution of seed dispersal effectiveness values, an often neglected source of variation in seed dispersal assemblages. Non-significant differences in seed dispersal effectiveness overlap support the hypothesis that two species are functional equivalent, thus playing similar functional roles. The model proposed is applicable to any other quantity or quality component and is independent from the method or sampling design used to quantify SDE. The identification of functional equivalent species in seed dispersal assemblages adds to the theoretical framework of seed dispersal effectiveness and offers new insights into the ecology of the seed dispersal service provided by birds.

Interhabitat variation in diplochory: Seed dispersal effectiveness by birds and ants differs between tropical forest and savanna

2019 ◽  
Vol 38 ◽  
pp. 48-57 ◽  
Author(s):  
Paulo H.S.A. Camargo ◽  
Suelen B.M. Rodrigues ◽  
Augusto J. Piratelli ◽  
Paulo S. Oliveira ◽  
Alexander V. Christianini
Keyword(s):  
Seed Dispersal ◽  
Tropical Forest ◽  
Seed Dispersal Effectiveness ◽  
Dispersal Effectiveness

Filling gaps in the seed dispersal effectiveness model for Prosopis flexuosa: quality of seed treatment in the digestive tract of native animals

2020 ◽  
Vol 30 (3) ◽  
pp. 215-223
Author(s):  
Claudia M. Campos ◽  
Liliana Ramos ◽  
Noelia Manrique ◽  
Mónica I. Cona ◽  
Carmen Sartor ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dispersal ◽  
Retention Time ◽  
Germination Percentage ◽  
Seed Dispersal Effectiveness ◽  
Rhea Americana ◽  
Mean Retention Time ◽  
Feeding Experiments ◽  
Prosopis Flexuosa ◽  
Dispersal Effectiveness

AbstractFor endozoochorous species, the quality component of seed dispersal effectiveness depends in part on the treatment seeds receive in the animal's gut. Covering a variety of taxa, diet, digestion system and body size of Prosopis flexuosa seed dispersers, we analysed differences among species in (1) mean retention time of ingested seeds, (2) recovery of viable seeds, (3) seed germination in comparison with seeds collected from trees and (4) germination of seeds after two different periods of retention in the gut. Feeding experiments were conducted with captive individuals of Dolichotis patagonum, Lycalopex gymnocercus, Rhea americana, Chelonoidis chilensis and Lama guanicoe. On the first day, we provided them with fruits containing controlled amounts of seed, and on the subsequent days, we collected faeces in order to recover seeds. We performed germination and viability tests on seeds coming from faeces and collected from trees. The results showed differences among species in the mean retention time of seeds. Chelonoidis chilensis had the longest mean retention time, but its effect on seed recovery and germination was similar to that of the other species, except for L. guanicoe, which showed the lowest seed recovery. When scarification and promotion of seed germination were considered, herbivorous mammals and tortoises (L. guanicoe, D. patagonum and C. chilensis) were the ones increasing germinability, whereas R. americana and L. gymnocercus did not significantly increase final seed germination percentage, which was similar to that for seeds collected from trees. P. flexuosa seeds receive a variety of treatments from endozoochorous dispersers, which might result in an overall fitness benefit for a plant living in unpredictable environments.

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