Vortrag, Integrating Mechanisms into Macroecology - 8th Annual Meeting of the Specialist Group for Macroecology of the Ecological Society of Germany, Austria, and Switzerland (GfÖ), Halle (Saale): 04.03.2014 - 06.03.2014
The role of environmental settings in shaping species distribution is still one of the major topics in macroecology. The signific ant effects of abiotic environmental conditions like climate have been shown in numer ous studies. However, effects of biotic environmental conditions like food ava ilability are still poorly understood. This even holds true for prominent s pecies like the Golden Eagle Aquila chrysaetos , although the role of optima l foraging on species performanc e has a strong theoretical background in ecology. Here we comb ined biogeographical information on range margins with biological information about foraging behavior and breeding success of Golden Eagles in a meta-analysis of 67 glo bally distributed studies. We observed a significant decrease of breedi ng success and portions of m edium-sized, optimal prey species within diets of br eeding Golden Eagles toward s the species distribution boundaries. Diet breadth and portions of sub- optimal small and large-sized prey species increased, however, towards the di stribution edge. Thus, availability of optimal-sized prey species is a crucial dr iver of foraging behaviour, breeding success and distribution of Golden Eagles on a global scale. However, underlying anthropogenic effects on opt imal prey availability have to be studied in more detail to fully understand the link between abiotic a nd biotic environment al conditions and species distribution patterns.