title: Above- and below-ground impacts of introduced predators in seabird-dominated island ecosystems.
abstract: 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.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fukami
authors.forename: David A
authors.initials: DA
authors.lastname: Wardle
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Bellingham
authors.forename: Christa P H
authors.initials: CP
authors.lastname: Mulder
authors.forename: David R
authors.initials: DR
authors.lastname: Towns
authors.forename: Gregor W
authors.initials: GW
authors.lastname: Yeates
authors.forename: Karen I
authors.initials: KI
authors.lastname: Bonner
authors.forename: Melody S
authors.initials: MS
authors.lastname: Durrett
authors.forename: Madeline N
authors.initials: MN
authors.lastname: Grant-Hoffman
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Williamson
mesh_terms: D000818:Animals; D018533:Biomass; D001717:Birds; D017753:Ecosystem; D020387:Food Chain; D005843:Geography; D009520:New Zealand; D011235:Predatory Behavior; D051381:Rats; D012987:Soil
chemical_list: D012987:Soil