title: Predator-prey relationships in a Mediterranean vertebrate system: Bonelli's eagles, rabbits and partridges.
abstract: How predators impact on prey population dynamics is still an unsolved issue for most wild predator-prey communities. When considering vertebrates, important concerns constrain a comprehensive understanding of the functioning of predator-prey relationships worldwide; e.g. studies simultaneously quantifying 'functional' and 'numerical responses' (i.e., the 'total response') are rare. The functional, the numerical, and the resulting total response (i.e., how the predator per capita intake, the population of predators and the total of prey eaten by the total predators vary with prey densities) are fundamental as they reveal the predator's ability to regulate prey population dynamics. Here, we used a multi-spatio-temporal scale approach to simultaneously explore the functional and numerical responses of a territorial predator (Bonelli's eagle Hieraaetus fasciatus) to its two main prey species (the rabbit Oryctolagus cuniculus and the red-legged partridge Alectoris rufa) during the breeding period in a Mediterranean system of south Spain. Bonelli's eagle responded functionally, but not numerically, to rabbit/partridge density changes. Type II, non-regulatory, functional responses (typical of specialist predators) offered the best fitting models for both prey. In the absence of a numerical response, Bonelli's eagle role as a regulating factor of rabbit and partridge populations seems to be weak in our study area. Simple (prey density-dependent) functional response models may well describe the short-term variation in a territorial predator's consumption rate in complex ecosystems.
authors.affiliation: Empresa de Gestión Medioambiental-Consejería de Medio Ambiente, Junta de Andalucía, Granada, Spain. mmoleonpaiz@hotmail.com
authors.forename: Marcos
authors.initials: M
authors.lastname: Moleón
authors.forename: José A
authors.initials: JA
authors.lastname: Sánchez-Zapata
authors.forename: José M
authors.initials: JM
authors.lastname: Gil-Sánchez
authors.forename: Elena
authors.initials: E
authors.lastname: Ballesteros-Duperón
authors.forename: José M
authors.initials: JM
authors.lastname: Barea-Azcón
authors.forename: Emilio
authors.initials: E
authors.lastname: Virgós
mesh_terms: D000818:Animals; D020307:Eagles / Q000502:physiology*; D020387:Food Chain; D046094:Galliformes / Q000502:physiology*; D019083:Mediterranean Region; D011156:Population Density; D011157:Population Dynamics; D011235:Predatory Behavior; D011817:Rabbits / Q000502:physiology*