title: Early warnings of regime shifts: a whole-ecosystem experiment.
abstract: Catastrophic ecological regime shifts may be announced in advance by statistical early warning signals such as slowing return rates from perturbation and rising variance. The theoretical background for these indicators is rich, but real-world tests are rare, especially for whole ecosystems. We tested the hypothesis that these statistics would be early warning signals for an experimentally induced regime shift in an aquatic food web. We gradually added top predators to a lake over 3 years to destabilize its food web. An adjacent lake was monitored simultaneously as a reference ecosystem. Warning signals of a regime shift were evident in the manipulated lake during reorganization of the food web more than a year before the food web transition was complete, corroborating theory for leading indicators of ecological regime shifts.
authors.affiliation: Center for Limnology, University of Wisconsin, Madison, WI 53706, USA. srcarpen@wisc.edu
authors.forename: S R
authors.initials: SR
authors.lastname: Carpenter
authors.forename: J J
authors.initials: JJ
authors.lastname: Cole
authors.forename: M L
authors.initials: ML
authors.lastname: Pace
authors.forename: R
authors.initials: R
authors.lastname: Batt
authors.forename: W A
authors.initials: WA
authors.lastname: Brock
authors.forename: T
authors.initials: T
authors.lastname: Cline
authors.forename: J
authors.initials: J
authors.lastname: Coloso
authors.forename: J R
authors.initials: JR
authors.lastname: Hodgson
authors.forename: J F
authors.initials: JF
authors.lastname: Kitchell
authors.forename: D A
authors.initials: DA
authors.lastname: Seekell
authors.forename: L
authors.initials: L
authors.lastname: Smith
authors.forename: B
authors.initials: B
authors.lastname: Weidel
mesh_terms: D000818:Animals; D001492:Bass; D018533:Biomass; D002734:Chlorophyll / Q000032:analysis; D017753:Ecosystem; D005399:Fishes; D020387:Food Chain; D005618:Fresh Water / Q000737:chemistry; D008954:Models, Biological; D017711:Nonlinear Dynamics; D010839:Phytoplankton; D011157:Population Dynamics; D015048:Zooplankton
chemical_list: D002734:Chlorophyll