Seed dispersal networks in the Galápagos and the consequences of alien plant invasions.
Proc Biol Sci
; 280(1750): 20122112, 2013 Jan 07.
Article
em En
| MEDLINE
| ID: mdl-23173203
ABSTRACT
Alien plants are a growing threat to the Galápagos unique biota. We evaluated the impact of alien plants on eight seed dispersal networks from two islands of the archipelago. Nearly 10 000 intact seeds from 58 species were recovered from the droppings of 18 bird and reptile dispersers. The most dispersed invaders were Lantana camara, Rubus niveus and Psidium guajava, the latter two likely benefiting from an asynchronous fruit production with most native plants, which facilitate their consumption and spread. Lava lizards dispersed the seeds of 27 species, being the most important dispersers, followed by small ground finch, two mockingbirds, the giant tortoise and two insectivorous birds. Most animals dispersed alien seeds, but these formed a relatively small proportion of the interactions. Nevertheless, the integration of aliens was higher in the island that has been invaded for longest, suggesting a time-lag between alien plant introductions and their impacts on seed dispersal networks. Alien plants become more specialized with advancing invasion, favouring more simplified plant and disperser communities. However, only habitat type significantly affected the overall network structure. Alien plants were dispersed via two pathways dry-fruited plants were preferentially dispersed by finches, while fleshy fruited species were mostly dispersed by other birds and reptiles.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Répteis
/
Aves
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Cadeia Alimentar
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Espécies Introduzidas
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Dispersão de Sementes
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Preferências Alimentares
Limite:
Animals
País como assunto:
America do sul
/
Ecuador
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article