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Subsidy hypothesis and strength of trophic cascades across ecosystems
Author(s) -
Leroux Shawn J.,
Loreau Michel
Publication year - 2008
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/j.1461-0248.2008.01235.x
Subject(s) - subsidy , ecosystem , trophic level , trophic cascade , ecology , environmental science , biology , food web , economics , market economy
Ecosystems are differentially open to subsidies of energy, material and organisms. This fundamental ecosystem attribute has long been recognized but the influence of this property on community regulation has not been investigated. We propose that this environmental attribute may explain variation in the strength of trophic cascades among ecosystems. Simply because of gravity, we should predict that systems with convex profiles receive low amounts of subsidies whereas systems with concave profiles act as spatial attractors, and receive high amounts of subsidies. The subsidy hypothesis states that ecosystems with high amounts of allochthonous inputs will experience the strongest trophic cascades. To test this hypothesis, we derive ecosystem models and investigate the effect of location and magnitude of subsidies on the strength of trophic cascades. Predictions from our models support the subsidy hypothesis and highlight the need to consider ecosystems as open to allochthonous flows.