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Native generalist herbivores promote invasion of a chemically defended seaweed via refuge‐mediated apparent competition
Author(s) -
Enge Swantje,
Nylund Göran Mikael,
Pavia Henrik
Publication year - 2013
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/ele.12072
Subject(s) - herbivore , generalist and specialist species , ecology , competition (biology) , algae , allelopathy , biology , habitat , botany , germination
Refuge‐mediated apparent competition was recently suggested as a mechanism that enables plant invasions. The refuge characteristics of introduced plants are predicted to enhance impacts of generalist herbivores on native competitors and thereby result in an increased abundance of the invader. However, this prediction has so far not been experimentally verified. This study tested if the invasion of a chemically defended seaweed is promoted by native generalist herbivores via refuge‐mediated apparent competition. The invader was shown to offer herbivores a significantly better refuge against fish predation compared with native seaweeds. Furthermore, in an experimental community, the presence of herbivores decreased the performance of neighbouring native seaweeds, but increased growth and relative abundance of the invader. These results provides the first experimental evidence that native generalist herbivores can shift a community towards a dominance of a well‐defended invader, inferior to native species in direct competitive interactions, by means of refuge‐mediated apparent competition.