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Efectos de la Invasión de Hormigas Exóticas sobre la Abundancia y el Éxito Reproductivo de Aves Insulares Endémicas
Author(s) -
DAVIS NAOMI E.,
O'DOWD DENNIS J.,
GREEN PETER T.,
NALLY RALPH MAC
Publication year - 2008
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1111/j.1523-1739.2008.00984.x
Subject(s) - ecology , biology , understory , invasive species , foraging , mutualism (biology) , nest (protein structural motif) , introduced species , seed dispersal , biological dispersal , canopy , population , biochemistry , demography , sociology
Biological invaders can reconfigure ecological networks in communities, which changes community structure, composition, and ecosystem function. We investigated whether impacts caused by the introduced yellow crazy ant ( Anoplolepis gracilipes ), a pantropical invader rapidly expanding its range, extend to higher‐order consumers by comparing counts, behaviors, and nesting success of endemic forest birds in ant‐invaded and uninvaded rainforest on Christmas Island (Indian Ocean). Point counts and direct behavioral observations showed that ant invasion altered abundances and behaviors of the bird species we examined: the Island Thrush ( Turdus poliocephalus erythropleurus ), Emerald Dove ( Chalcophaps indica natalis ), and Christmas Island White‐eye ( Zosterops natalis ). The thrush, which frequents the forest floor, altered its foraging and reproductive behaviors in ant‐invaded forest, where nest‐site location changed, and nest success and juvenile counts were lower. Counts of the dove, which forages exclusively on the forest floor, were 9–14 times lower in ant‐invaded forest. In contrast, counts and foraging success of the white‐eye, a generalist feeder in the understory and canopy, were higher in ant‐invaded forest, where mutualism between the ant and honeydew‐secreting scale insects increased the abundance of scale‐insect prey. These complex outcomes involved the interplay of direct interference by ants and altered resource availability and habitat structure caused indirectly by ant invasion. Ecological meltdown, rapidly unleashed by ant invasion, extended to these endemic forest birds and may affect key ecosystem processes, including seed dispersal.