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Bears benefit plants via a cascade with both antagonistic and mutualistic interactions
Author(s) -
Grinath Joshua B.,
Inouye Brian D.,
Underwood Nora
Publication year - 2015
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.12396
Subject(s) - herbivore , predation , trophic cascade , ecology , biology , mutualism (biology) , arthropod , trophic level , predator
Predators can influence primary producers by generating cascades of effects in ecological webs. These effects are often non‐intuitive, going undetected because they involve many links and different types of species interactions. Particularly, little is understood about how antagonistic (negative) and mutualistic (positive) interactions combine to create cascades. Here, we show that black bears can benefit plants by consuming ants. The ants are mutualists of herbivores and protect herbivores from other arthropod predators. We found that plants near bear‐damaged ant nests had greater reproduction than those near undamaged nests, due to weaker ant protection for herbivores, which allowed herbivore suppression by arthropod predators. Our results highlight the need to integrate mutualisms into trophic cascade theory, which is based primarily on antagonistic relationships. Predators are often conservation targets, and our results suggest that bears and other predators should be managed with the understanding that they can influence primary producers through many paths.