Forest Habitat Networks for Biodiversity on Montréal Island Msc. Maria Dumitru (1,2) , Dr. Bronwyn Rayfield (1), Dr. Andrew Gonzalez (1) & Dr. Pierre André (2) Department of Biology, McGill University, 1205 Avenue Dr. Penfield, Montréal (Qc), Canada, H3A121 Département de Géographie, Université de Montréal, Pavillon 520 Côte-Ste-Catherine, Montréal (Qc), H2V 2B8 The Island of Montreal has less than 7% forest cover, which is below the 30% critical threshold for biodiversity. Habitat corridors can reduce isolation and increase habitat connectivity. Giant Swallowtail Habitat: open woodlands and nearby fields. It is the largest butterfly found in Canada. Pink-edged Sulphur Habitat: scrubby openings in wooded areas and bogs where blueberries grow. Northern Pearly-Eye Habitat: rich deciduous or mixed wooded areas. He is a shade-loving butterfly. Appalachian Brown Habitat: woodland butterfly, often found in wet sedge areas near the edge of woods. Little Wood-Satyr Habitat: near woods or shrubby areas. Figure 1. Examples of riverine and urban corridors. Why is habitat connectivity important for biodiversity? It allows species to move between habitat fragments to find food, mates and shelter. Link length less then 500 m What is a habitat network? A system of habitat patches connected by species movements and biodiversity. The three essential elements of a habitat network are: core areas, buffers, and corridors. Figure 3 . Potential habitat network for butterfly species on Montreal Island White-tailed deer Habitat: clearings, hardwood forests and mixed forests, abandoned fields and orchards, edges of marshes, river and swamp covered with cedar. Raccoon Habitat: variety of habitats where they can find water, food and shelter. He prefers hardwood wetlands, floodplain forests, salt marshes and freshwater marshes, and cultivated or abandoned farmlands. Figure 2. Habitat network in which a node represents a forest patch and a link represents the potential movement of a species. Coyote Habitat: woodland in agriculture areas that were once wholly occupied by the forest, grass fields, scrubs. Red Fox Habitat: all kinds of habitat, near the forest, in a dense forest near marshes surrounded by bushes or it goes willingly populated areas. Methods: The forest area is represented using a resolution of 0.09 ha/cell (30m x 30m). To understand forest habitat connectivity as perceived by different groups of species we simulate three scenarios corresponding to potential dispersal of butterflies, mammals, and birds (Figures 3 - 5). Habitat networks are defined for each group of species by including links less than their potential dispersal abilities. Link length less then 1500 m Figure 4. Potential habitat network for mammals species on Montreal Island Results: The entire island is connected with corridors of 2500 meters (Figure 5). The importance of each habitat patch in maintaining overall habitat network connectivity varies depending on the dispersal threshold of the focal species. Cooper's Hawk Habitat: conifer forests, mixed forests, deciduous forests with important leafs cover and surrounded by large open areas for hunting. Wood Thrush Habitat: breeds in deciduous and mixed forests with large trees and a layer of brush. Scarlet Tanager Habitat: breeds in deciduous forests, mixed conifers and deciduous forest, especially mature forests and occasionally in suburban areas with large trees. Red-shouldered hawk Habitat: various forest types (deciduous forests, mixed conifers and deciduous forest), riparian areas, wetlands and flooded hardwood forests. Ruby-throated Hummingbird Habitat: deciduous forest, pine forests and forest edges, orchards, and gardens. Canada has five species of hummingbirds, but only the ruby-throated hummingbird is found in the eastern part of Canada. Conclusion: A habitat network can sustain connectivity and biodiversity and would greatly benefit the island of Montreal. Network analysis can aid corridor design and sustainable land-use planning. Link length less then 2500 m Figure 5 Potential habitat network for birds species on Montreal Island