Bird community patterns in sub– Mediterranean pastures: the effects of shrub cover and grazing intensity. Animal Biodiversity and Conservation

Abstract Bird community patterns in sub-Mediterranean pastures: the effects of shrub cover and grazing intensity.-Shrubs are widely considered a threat to grassland biodiversity. We investigated the effects of shrub cover and grazing intensity on bird communities in sub-Mediterranean pastures in Bulgaria. The point-count method was used on 80 plots in open (< 10% shrub cover) and shrubby (approx. 20% cover) pastures under either intensive or extensive management (grazing intensity) from 2008 to 2009. We recorded a total of 1,956 observations of birds from 53 species. Main environmental gradients accounting for the bird community pattern were related to vegetation succession and land productivity. Bird species richness was higher in shrubby pastures than in open sites, while no effect was found in respect to total bird abundance. Bird species diversity (i.e. H' index) was highest in extensive shrubby pastures. Shrubland specialists were positively affected by shrub cover and extensive management of pastures while grassland and woodland specialists showed no significant response to these factors. We conclude that a small proportion of shrubs within pastures may be beneficial for farmland birds and sustainable management of pastures could be achieved by greater flexibility of national agri-environmental schemes. Key words: Agri-environmental scheme, Farmland birds, Grassland management, Semi-natural habitats, Shrubby vegetation. Resumen Patrones de las comunidades de aves en los pastos submediterráneos: el efecto de la cubierta arbustiva y la intensidad de pastoreo.-Se suele considerar a los arbustos como una amenaza a la biodiversidad de los pastos. Investigamos los efectos de la cubierta arbustiva y la intensidad del pastoreo sobre las comunidades de aves en los pastos submediterráneos de Bulgaria. Se utilizó el método de estaciones de escucha en 80 puntos de registro en pastos abiertos (cubierta arbustiva < 10%) y arbustivos (aproximadamente un 20% de la superficie cubierta), con una gestión de pastoreo tanto intensiva como extensiva desde 2008 a 2009. Registramos un total de 1.956 observaciones de aves pertenecientes a 53 especies distintas. Los gradientes ambientales principales responsables de los patrones de las comunidades de aves se relacionaron con la sucesión de la vegetación y la productividad de la tierra. La riqueza de especies de aves era mayor en los pastos arbustivos que en los lugares abiertos, aunque no se observó efecto alguno con respecto a la abundancia total de aves. La mayor diversidad de especies de aves (índice H') se daba en los pastos arbustivos con gestión extensiva. Los especialistas en zonas arbustivas se veían afectados positivamente por la cubierta arbustiva y la gestión extensiva de los pastos, mientras que los especialistas de praderas y bosques no presentaron ninguna respuesta positiva a dichos factores. Nuestra conclusión es que una pequeña proporción de arbustos dentro de los pastos puede ser beneficiosa para las aves de tierras de labrantío, y la gestión sostenible de los pastos podría alcanzarse mediante una mayor flexibilidad de los esquemas agroambientales nacionales

Breeding performance and population trend of the Egyptian Vulture Neophron percnopterus in Bulgaria: conservation implications

The Egyptian Vulture (Neophron percnopterus) has been classified as ‘Endangered’ due to rapid population declines across its range. Thus, exhaustive studies on its demography may serve as an important stepping stones for successful conservation programs. Breeding performance is one of the main components of the demography of a raptor population. Evaluating reproductive rates is easier than other demographic parameters, while remaining a very useful metric to identify factors driving raptor population trends. Here we present the breeding performance of the species’ population in Bulgaria as a result of a long-term monitoring (2005–2016). The studied population shows high breeding performance, based on a breeding success (1.11 ± 0.13 fledglings / laying pairs), productivity (0.88 ± 0.1 fledglings / occupied territories) and fledgling success (1.2 ± 0.1 fledglings / successful pairs), all among the highest recorded in Europe. Pairs breeding in territories with high occupancy rate produced 88% of the fledglings

Assessing genetic diversity patterns at neutral and adaptive loci to inform population reinforcement of an endangered migratory vulture

One of the primary goals of conservation translocation programs should be the maintenance of both population demographic stability and genetic diversity. Here, we provide genetic management recommendations to inform a population reinforcement of the declining Egyptian Vulture population in the Balkans. Specifically, we examined whether the number of released individuals is sufficient to prevent genetic diversity loss due to random genetic drift and what the origin of the individuals should be that comprise the captive breeding pool. To this aim, we estimated and assessed genetic diversity levels and genetic structure of Egyptian Vulture populations across much of the species’ range using both neutral and non-neutral candidate loci involved in migration. We then evaluated the effects of the currently proposed population management scheme and candidate source populations on retaining allelic diversity. Our results show low differentiation values among populations and absence of genetic structure which point to past high gene flow. Furthermore, there was no predicted significant impact of different source populations on the genetic diversity of the recipient Balkan population. We also found that the declining Egyptian Vulture population in the Balkans still retains high levels of genetic diversity and therefore genetic diversity restoration is not currently needed. However, without any management, diversity is likely to decrease fast because of increased genetic drift as the population size continues to decline. Population reinforcement with nine birds per year for 20 years would provide sufficient demographic support for the population to retain > 85% of rare allelic diversity. Birds originating from the Balkans would ensure ecological and behavioral similarity and thus would be the best option for reinforcement. Nevertheless, our results demonstrate that to prevent further population contraction and loss of adaptive alleles, releasing individuals of different origin would also be appropriate