title: Temperature dependence of predation depends on the relative performance of predators and prey.
abstract: The temperature dependence of predation rates is a key issue for understanding and predicting the responses of ecosystems to climate change. Using a simple mechanistic model, we demonstrate that differences in the relative performances of predator and prey can cause strong threshold effects in the temperature dependence of attack rates. Empirical data on the attack rate of northern pike (Esox lucius) feeding on brown trout (Salmo trutta) confirm this result. Attack rates fell sharply below a threshold temperature of +11°C, which corresponded to a shift in relative performance of pike and brown trout with respect to maximum attack and escape swimming speeds. The average attack speed of pike was an order of magnitude lower than the escape speed of brown trout at 5°C, but approximately equal at temperatures above 11°C. Thresholds in the temperature dependence of ecological rates can create tipping points in the responses of ecosystems to increasing temperatures. Thus, identifying thresholds is crucial when predicting future effects of climate warming.
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå 901 87, Sweden gunnar.ohlund@emg.umu.se.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Öhlund
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå 901 87, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hedström
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå 901 87, Sweden.
authors.forename: Sven
authors.initials: S
authors.lastname: Norman
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå 901 87, Sweden Climate Impacts Research Centre (CIRC), Abisko Scientific Research Station, Abisko 981 07, Sweden.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Hein
authors.affiliation: Department of Ecology and Environmental Science, Umeå University, Umeå 901 87, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Englund
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D057231:Climate Change; D017753:Ecosystem; D017859:Esocidae / Q000502:physiology*; D011157:Population Dynamics; D011235:Predatory Behavior; D012621:Seasons; D013550:Swimming; D013696:Temperature; D014337:Trout / Q000502:physiology*
keywords: brown trout; northern pike; predation; swimming speed; temperature; tipping points