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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 124. No. 2. June 2012 
around parent plants, making them especially 
vulnerable to seed predators (McConkey and 
Drake 2002, Chimera and Drake 2011), in this 
case, ground finches or rodents. However, intro¬ 
duced rodents act as both seed predators and seed 
dispersers, which may also contribute to the 
spread of L. camara as occurred in the Hawaiian 
Islands (Shiels 2011. Shiels and Drake 2011). 
Most seedlings recorded under L. camara adult 
plants were rooted in fissures between rocks 
where they were less accessible to predators. 
Seeds of L camara would have a higher 
probability to survive post-dispersal predation in 
fissures between rocks, and/or they would find 
more appropriate environment for germination 
and establishment as soil moisture is higher than 
on non rocky surfaces. 
Introduction of invasive species can alter 
ecosystem function, resulting in direct species 
ieplaccment and changes in ecosystem processes 
that control plant and animal activities (Mack and 
D'Antonio 1996). Food during the cool dry season 
in the Dry Zone of Galapagos is scarcer than 
during the wetter season, and availability of /.. 
camara fruits represents an important food source 
for the finches. Availability of the invasive 
Imm ana could be altering the feeding behavior 
of endemic finches, and changing their interac¬ 
tions with endemic or native plant species such as 
L. pedimcularis, which also grows in the Dry 
Zone invaded by L camara. It is not known 
whether the availability of the more abundant L 
camara fruits might benefit the endemic congener 
by reducing predation pressure by finches, or 
whether it might disadvantage it, by reducing 
dispersal of its fruit. Little predation was observed 
on L. peduncularis fruits (just 6% of the total fruit 
production, unpubl. data). 
Transport of seeds by frugivores from the 
parent plant could improve the overall chances 
of seedling dispersal to suitable establishment 
sites (Schupp 1993, 1995; Schupp and Fuentes 
1995) but no birds were observed carrying L. 
camara fruits. Our observations were concen¬ 
trated in the dry season, when fruits are 
completely dry and perhaps relatively unappe¬ 
tizing for frugivores, although at higher altitudes 
it was observed that both finch species also 
crushed fresh fruits of L. camara (J. Carridn- 
Intact seeds of L. camara have been found in 
the stomach of the invasive Smooth-billed Am 
{Crotophaga uni) (Guerrero and Tye 2011). Buis, 
an introduced bird species could be a long distance 
disperser of L. camara fruits in Galapagos, as in the 
Hawaiian Islands, where no native bird has been 
observed eating L camara fruits but six introduced 
bird species have been implicated in its spread 
(Perkins and Swezey 1924, Day et al. 2003.Chimera 
and Drake 2010). Experiments with captive Gafa- 
pagos Mockingbirds (Mimas pamilus ) revealed 
they eat L camara seeds, and seed viability wjs 
not significantly different after passing through ;is 
gut (Buddenhagen and Jewell 2006). 
Effective vertebrate seed dispersal is an impor¬ 
tant attribute of successful woody plant invaders 
(Rejmanek 1996, Westcott and Fletcher 2011) L 
camara already occupied 2,000 ha in the Galapa¬ 
gos Islands by 1987, and the absence of specialist 
frugivores in the islands may reduce the dispersal 
and invasion velocity of L. camara. Seed 
predation by the endemic ground finches and 
other animals may reduce L camara'a rate of 
spread and therefore its impact on the Galapagos 
ecosystem (finches removed —15% of L camara 
Iruits in just 1 month). This effect could be 
reduced by birds such as the Smooth-billed Ani. 
which was introduced to Galapagos in l%0 v 
(Rosenberg et al. 1990), or other generalist 
frugivores that could facilitate seed dissemination 
and invasion of L. camara or other fleshy-fruitcd 
non-native species. 
ACKNOWLEDGMENTS 
This research was supported by ‘Agenda EspanoU & 
Cooperacidn Internacional para el Desarrollo' (AD- - 
through a grant to the first author and ‘El Plan Pn-T ID L 
Investigacidin de la Universidad de Sevilla’ We thank the*’’ 
of Galapagos National Park for providing the research pemi.: 
and Mabel Gonzalez and Tania Quisingo for field 
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