title: Unexpected consequences of control: competitive vs. predator release in a four-species assemblage of invasive mammals.
abstract: Invasive species are frequently the target of eradication or control programmes to mitigate their impacts. However, manipulating single species in isolation can lead to unexpected consequences for other species, with outcomes such as mesopredator release demonstrated both theoretically and empirically in vertebrate assemblages with at least two trophic levels. Less is known about the consequences of species removal in more complex assemblages where a greater number of interacting invaders increases the potential for selective species removal to result in unexpected changes in community structure. Using a replicated Before-After Control-Impact field experiment with a four-species assemblage of invasive mammals we show that species interactions in the community are dominated by competition rather than predation. There was no measurable response of two mesopredators (rats and mice) following control of the top predator (stoats), but there was competitive release of rats following removal of a herbivore (possums), and competitive release of mice following removal of rats.
authors.affiliation: Landcare Research, PO Box 40, Lincoln 7640, New Zealand. ruscoew@landcareresearch.co.nz
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Ruscoe
authors.forename: David S L
authors.initials: DS
authors.lastname: Ramsey
authors.forename: Roger P
authors.initials: RP
authors.lastname: Pech
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Sweetapple
authors.forename: Ivor
authors.initials: I
authors.lastname: Yockney
authors.forename: Mandy C
authors.initials: MC
authors.lastname: Barron
authors.forename: Mike
authors.initials: M
authors.lastname: Perry
authors.forename: Graham
authors.initials: G
authors.lastname: Nugent
authors.forename: Roger
authors.initials: R
authors.lastname: Carran
authors.forename: Rodney
authors.initials: R
authors.lastname: Warne
authors.forename: Chris
authors.initials: C
authors.lastname: Brausch
authors.forename: Richard P
authors.initials: RP
authors.lastname: Duncan
mesh_terms: D000818:Animals; D044822:Biodiversity; D003163:Competitive Behavior / Q000502:physiology*; D017753:Ecosystem; D058865:Introduced Species; D051379:Mice; D011156:Population Density; D011235:Predatory Behavior / Q000502:physiology*; D051381:Rats