| Agricultural expansion and intensification are considered major contributors to biodiversity loss worldwide. However, agricultural landscapes still contain considerable biodiversity, often providing ecosystem services crucial for production.;The "farmland bird" approach shows promise for monitoring, assessment and management of agricultural landscapes in North America as in Europe.;Farmland birds are recognized in Europe, but not in North America. Based on the EU approach, a list of farmland birds was compiled for Ontario using literature review and expert opinion. Regression analysis for 54 species using point counts from the 2001-2005 Ontario Breeding Bird Atlas with statistics for 181 subdivisions from the 2006 Census of Agriculture was conducted to validate retention and refine categorization of species. The final list for Ontario included 45 species, comprised of 34 specialists (6 row crop, 16 pasture and 12 farmstead) and 11 edge generalists. Landscape structure (especially composition but also configuration and heterogeneity) was more important than practices for richness and abundance of all farmland birds, specialists, generalists and Bird Conservation Region 13 priority species based on statistical comparison of regression models. Subsetting subdivisions (by % farmland) showed that effects of landscape structure (especially composition) on abundance of specialists and edge generalists varied in relation to agricultural extent and intensity. Effects of practices were also more evident. Because tradeoffs existed across the gradient in landscape composition, farmland bird abundance was optimized when row crop occupied 40% to 70% of subdivisions (with 8 to 10% pasture). |
