Effects of climate change on trait-based dynamics of a top predator in freshwater ecosystems.
Predicted universal responses of ectotherms to climate warming include increased maximum population growth rate and changes in body size through the temperature-size rule. However, the mechanisms that would underlie these predicted responses are not clear. Many studies have focused on proximate mechanisms of physiological processes affecting individual growth. One can also consider ultimate mechanisms involving adaptive explanations by evaluating temperature effects on different vital rates across the life history and using the information in a population dynamical model. Here, we combine long-term data for a top predator in freshwater ecosystems (pike; Esox lucius) with a stochastic integral projection model to analyze concurrent effects of temperature on vital rates, body size, and population dynamics. As predicted, the net effect of warming on population growth rate (fitness) is positive, but the thermal sensitivity of this rate is highly size- and vital rate-dependent. These results are not sensitive to increasing variability in temperature. Somatic growth follows the temperature-size rule, and our results support an adaptive explanation for this response. The stable length structure of the population shifts with warming toward an increased proportion of medium-sized but a reduced proportion of small and large individuals. This study highlights how demographic approaches can help reveal complex underlying mechanisms for population responses to warming.
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway.
Yngvild
Y
Vindenes
Eric
E
Edeline
Jan
J
Ohlberger
Oystein
O
Langangen
Ian J
IJ
Winfield
Nils C
NC
Stenseth
L Asbjørn
LA
Vøllestad
D000818:Animals; D049628:Body Size; D057231:Climate Change; D017753:Ecosystem; D017859:Esocidae / Q000502:physiology*; D005260:Female; D005298:Fertility; D060106:Lakes; D008954:Models, Biological; D011157:Population Dynamics; D013696:Temperature; D006113:United Kingdom