Exotic lagomorph may influence eagle abundances and breeding spatial aggregations: a field study and meta-analysis on the nearest neighbor distance

BARBAR, F.; IGNAZI, G.O.; HIRALDO, F.; LAMBERTUCCI, S A

PeerJ

PeerJ Inc

Año: 2018 vol. 6 p. 1 - 17

2167-8359

The introduction of alien species could be changing the food source composition, ultimately restructuring demography and spatial distribution of native communities. In Argentine Patagonia, the exotic European hare has one of the highest numbers recorded worldwide and is now a widely consumed prey for many predators. We examine the potential relationship between abundance of this relatively new prey and the abundance and breeding spacing of one of its main consumers, the Black-chested Buzzard-Eagle (Geranoaetus melanoleucus). First we analyze the abundances of individuals of a raptor guild in relation to hare abundances through a correspondence analysis. We then estimated the Nearest Neighbor Distance (NND) of the Black-chested Buzzard-eagle abundances in the two areas with high hare abundances. Finally, we performed a meta-regression between the NND and the body masses of Accipitridae raptors, to evaluate if Black-chested Buzzard-eagle NND deviates from the expected accordingly to their mass. We found that eagles abundances were highly associated with hare abundances, more than any other raptor species in the study area. Their NND deviate from the value expected, which was significantly lower than expected for a raptor species of this size in two areas with high hare abundances. Our results support the hypothesis that high local abundance of prey leads to a reduction of the breeding spacing of its main predator, which could be potentially altering other interspecific interactions, and thus the entire community.