Double-Crested Cormorant Disturbance: Restoration Potential for a Forested Urban Park

This paper examines the relationship between double-crested cormorant nesting activity and urban deforestation in Toronto’s Tommy Thompson Park (TTP). TTP is located on a human constructed spit, providing habitat for colonial waterbirds to nest along Lake Ontario’s shoreline. In recent decades, double-crested cormorant colonization has resulted in the deforestation of the western edge of the park. This deforestation is causing a steady retreat of tree cover, where newly exposed soils are vulnerable to colonization by invasive plants and erosive wind and wave action. Following a 30x30 m systematic sampling approach, geospatial interpolation of point data describing current soil physical and chemical properties is used to create continuous soil prediction surfaces. Interpolated surfaces are then combined to create site suitability maps using multicriteria evaluation (MCE) to weight the soil variables, and to provide a ranked output of desirable site locations for species-specific re-vegetation potential. Keywords: double-crested cormorant, urban forestry, restoration, kriging, multi-criteria evaluation