title: Effects of an invasive predator cascade to plants via mutualism disruption.
abstract: Invasive vertebrate predators are directly responsible for the extinction or decline of many vertebrate species, but their indirect impacts often go unmeasured, potentially leading to an underestimation of their full impact. When invasives extirpate functionally important mutualists, dependent species are likely to be affected as well. Here, we show that the invasive brown treesnake, directly responsible for the extirpation of forest birds from the island of Guam, is also indirectly responsible for a severe decline in plant recruitment as a result of disrupting the fruit-frugivore mutualism. To assess the impact of frugivore loss on plants, we compare seed dispersal and recruitment of two fleshy-fruited tree species on Guam and three nearby islands with intact disperser communities. We conservatively estimate that the loss of frugivorous birds caused by the brown treesnake may have caused a 61-92% decline in seedling recruitment. This case study highlights the potential for predator invasions to cause indirect, pervasive and easily overlooked interaction cascades.
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, 251 Bessey Hall, Iowa State University, Ames, Iowa 50011, USA.|Department of Biology, University of Washington, Seattle, Washington 98195, USA.|Department of BioSciences, Rice University, Houston, Texas 77005, USA.
authors.forename: Haldre S
authors.initials: HS
authors.lastname: Rogers
authors.affiliation: Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, Seattle, Washington 98112, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Buhle
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Janneke
authors.initials: J
authors.lastname: HilleRisLambers
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, 251 Bessey Hall, Iowa State University, Ames, Iowa 50011, USA.|Department of Biology, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Evan C
authors.identifier: 0000-0002-0520-4200
authors.initials: EC
authors.lastname: Fricke
authors.affiliation: Western Pacific Tropical Research Center, University of Guam, Mangilao, Guam 96923, USA.
authors.forename: Ross H
authors.initials: RH
authors.lastname: Miller
authors.affiliation: Colorado Global Hub, Future Earth, Colorado 80309, USA.|Sustainability Innovation Lab at Colorado, University of Colorado, Boulder, Colorado 80309, USA.|School of Global Environmental Sustainability, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Tewksbury
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology; D017812:Colubridae / Q000502:physiology*; D017753:Ecosystem; D053476:Extinction, Biological; D005638:Fruit; D018525:Germination; D006141:Guam; D058865:Introduced Species; D008962:Models, Theoretical; D018521:Plant Physiological Phenomena; D011157:Population Dynamics; D011235:Predatory Behavior; D058614:Seed Dispersal