Does hunting management affect non-game bird species? A study from Spain and Portugal

Resumen del trabajo presentado a la International Conference on Hunting for Sustainability: "Ecology, Economics and Society", celebrada en Ciudad Real (España) del 27 al 29 de marzo de 2012.In Europe, hunting and its associated management has been performed for centuries and has potentially had profound effects on landscapes and on the biodiversity they hold. We investigated the effect of hunting management on non-target bird species. For doing so, we explored the relationship between hunting management and different groups of birds of conservation concern. We conducted the study with two different approximations. In a first step, we assessed whether there were a higher abundance or species richness in hunting estates with game management than in those without management. This survey was conducted in 24 game estates in South Portugal in spring and summer 2001-2002. Twelve of the hunting estates performed game management activities for small-game species while the other 12 corresponded to areas open to hunters but where no game management was undertaken. Groups of species considered in the study were passerines, steppe-birds, ground-nesting birds and endangered birds. We modelled the abundance and number of species of each bird group in each estate according to the game management regime (with/without game management) and to habitat variables with GLMMs and selected the models with lowest AICc. Our results show that all groups of species considered (except passerines) were more abundant or more diverse in hunting estates where game management was performed. In a second step, we aimed to know if our previous result was also relevant in another study area, as well as to disentangle which management activities could specifically affect bird diversity. We surveyed 54 small-game hunting estates in Central Spain with varying management intensity in spring and/or summer 2006-2010. Groups of species considered were raptors and steppe-birds. Information about game management was gathered through interviews with game managers. We modelled the abundance and species richness of each bird group in each estate according to habitat and game management variables (type of hunting regime, artificial feeding, predator control, number of keepers and partridge abundance) with GLMMs and selected the models with lowest AICc. Our results showed that management implemented for red-legged partridges (Alectoris rufa) did not seem to have neither positive nor negative effects on the abundance of their predators (raptors), but having good densities of partridges had a positive effect on the number of raptor species. However, some activities leading to improve red-legged partridges (in particular, supplementary feeding and predator control) had a positive effect on steppe-birds, which share habitat requirements with them. Therefore, we conclude that game management activities have positive effects on different groups of bird species in the Iberian Peninsula. All models are affected by habitat variables, so it is very important to maintain the habitat that allows those high densities and that has a positive effect on biodiversity.Peer Reviewe