Abstract :
Over the past half century, grassland birds in Europe have declined dramatically and in order to
maintain and restore their populations it is critical to understand how habitat structures and quality
within pastures affect birds. This study investigated the effects of habitat structure and pasture
abandonment on grassland birds in IBA Ponor, western Bulgaria. Birds were sampled using the
point count method at 143 randomly located circular plots and a total of 1,401 observations of birds
from 31 species were recorded. The results showed that habitat complexity, management and
landscape position influenced bird community structure and species occurrence within the upland
pastures. Extensively grazed pastures supported higher structural complexity of vegetation cover
and higher bird-species richness and diversity compared with abandoned ones. Moreover, bird
species with a preference for grazed rather than abandoned pastures had higher conservation status
and most were associated with shrub cover. To maintain high levels of avian diversity, habitat
complexity within pastures should be maintained through extensive grazing, to ensure availability
of scrub vegetation wherever possible. Finally, this study provided evidence that agri-environmental
schemes should not be directly extrapolated from one country or region to another without
been tested first, because within the same management, differences in habitat structural characteristics
may exist due to the landscape and socio-economic characteristics of the region.
