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Above‐ and below‐ground impacts of introduced predators in seabird‐dominated island ecosystems
Author(s) -
Fukami Tadashi,
Wardle David A.,
Bellingham Peter J.,
Mulder Christa P. H.,
Towns David R.,
Yeates Gregor W.,
Bonner Karen I.,
Durrett Melody S.,
GrantHoffman Madeline N.,
Williamson Wendy M.
Publication year - 2006
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2006.00983.x
Subject(s) - ecosystem , predation , seabird , trophic level , ecology , food web , biota , trophic cascade , biomass (ecology) , biology , disturbance (geology) , environmental science , ecosystem engineer , paleontology
Predators often exert multi‐trophic cascading effects in terrestrial ecosystems. However, how such predation may indirectly impact interactions between above‐ and below‐ground biota is poorly understood, despite the functional importance of these interactions. Comparison of rat‐free and rat‐invaded offshore islands in New Zealand revealed that predation of seabirds by introduced rats reduced forest soil fertility by disrupting sea‐to‐land nutrient transport by seabirds, and that fertility reduction in turn led to wide‐ranging cascading effects on belowground organisms and the ecosystem processes they drive. Our data further suggest that some effects on the belowground food web were attributable to changes in aboveground plant nutrients and biomass, which were themselves related to reduced soil disturbance and fertility on invaded islands. These results demonstrate that, by disrupting across‐ecosystem nutrient subsidies, predators can indirectly induce strong shifts in both above‐ and below‐ground biota via multiple pathways, and in doing so, act as major ecosystem drivers.