Direct and Indirect Effects of Agricultural Land Cover on Bird Species Richness

Abstract

Agriculture is one of the largest threats to global biodiversity including to birds. But we know little about whether the effects of agriculture on birds are mainly direct through farming operations, or indirect through effects on natural habitats. We sampled birds at 127 sites in eastern Ontario Canada. We used structural equation modelling (SEM) to evaluate the direct and indirect effects of agriculture on species richness of three bird guilds: forest birds, shrubedge birds, and grassland birds. We found that forest bird richness was driven by the negative indirect effect of cropland via habitat loss. Shrub-edge and grassland bird richness increased with the amount of agriculture, despite negative indirect effects. Management efforts for bird diversity in agricultural landscapes should focus on preserving grassland and forest habitat including forest edges, while managing agricultural land, for instance, by selecting perennial crops and low impact agricultural activities. from both of you. I would like to thank Julia Put from Carleton University and Christine Eberl, Dr. Gregory Mitchell, and Dr. Scott Wilson at the National Wildlife Research Center for their assistance preparing for and conducting field work. Thanks also to Kevin Hannah at Environment and Climate Change Canada for providing field equipment and funding for an expert to identify the bird species from the survey data. I would also like to thank Lindsay Daly, Adrianne Hajdasz, and Joe Gabriel from the Geomatics and Landscape Ecology Lab (GLEL) for sharing their methods for corridor connectivity. This project would not have been possible without the funding and support provided by Environment and Climate Change Canada.