Later onset of breeding in an apex predator in response to climate change: causes and consequences
Final Report Abstract
Climate change poses one of the most fundamental risks to wildlife populations and biodiversity in the 21st century. Long-term studies are vital to obtain a deeper understanding of the causes and consequences of this change, especially in apex predators. In a population of common buzzards Buteo buteo, average onset of breeding has shifted backwards by roughly ten days over the time period 1990-2013, despite warmer temperatures. This research project explored which mechanism might best explain this paradoxical result and elucidate the complexity of organisms’ responses to climate change. With data covering breeding times, reproductive success, life histories of individuals and fitness, five major hypotheses could be tested. Later breeding was not explained by an adaptive evolutionary response, not by phenotypic plasticity, nor by worsening of individual condition or changes in the age structure or plumage distribution. Instead, our results suggest that the later breeding is a consequence of relaxed selection pressure by climate and an increased population density that selects for synchronous breeding. We also modelled population dynamics over time and found that annual survival increased in this buzzard population and that this increase in survival is sufficient to explain the population increase that has been documented for this buzzard population over the last 25 years. The results obtained in this research project document the complex interplay between climate change, population ecology and the way individuals respond to both changes as part of their life history.
Publications
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(2013) Does systematic variation improve the reproducibility of animal experiments? Nature methods 10: 373
Jonker, R. M., Guenther, A., Engqvist, L. & Schmoll, T.
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(2013) Variation at phenological candidate genes correlates with timing of dispersal and plumage morph in a sedentary bird of prey. Mol. Ecol. 22: 5430-5440
Chakarov, N., Jonker, R. M., Boerner, M., Hoffman, J. I. & Krüger, O.
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(2014) Climate change and habitat heterogeneity drive a population increase in Common Buzzards Buteo buteo through effects on survival. Ibis 156: 97-106
Jonker, R. M., Chakarov, N. & Krüger, O.
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(2014) Territory quality affects the relative importance of habitat heterogeneity and interference competition in a longlived, territorial songbird. J. Avian. Biol. 45: 15-21
Grünkorn, T., Potiek, A., Looft, V., Jonker, R. M., Chakarov, N. & Krüger, O.
