Living on the edge

Across the globe, human development has increased the fragmentation of once-continuous landscapes and ecosystems into isolated patches of natural habitat. Roads, towns, fences, public parks, and farms are all examples of human artifacts that alter the pattern of the landscape.

Urbanization is causing humans to continuously fragment landscapes and thus increase the edge effect. The Edge effect is a term used to describe the changes in biodiversity that occur inside the space surrounding the shared edge of two or more distinct ecosystems. This transitional zone can be richer in biodiversity (called the ecotone) and the obvious examples are between woodlands and plains, forests and mountains, and land and water. The animals that have colonized areas on campus tend to be those that require two or more habitats, such as Eastern Cottontail rabbits, Red Foxes, Blue Jays, and American Robins. But the edge effect can also mean that some species cannot support themselves because the area of the secondary habitat is not large enough for them and this can mean less biodiversity.


On the campus where the land meets the water is often the most interesting space for biodiversity.  Lac-St-Louis is a lake that has a lot of aquatic life in it and many species of birds and mammals are interested in eating that aquatic life.  In the winter when the lake is frozen many animals use it to travel on.  Coyotes and Red Foxes travel on it to easily get to different habitats and islands that they wouldn’t be able to access as easily when the lake is not frozen. In the spring and summer Canada Geese enjoy eating plants and insects off the campus lawns and eating the aquatic life in the lake. Red-winged Blackbirds are present and they prefer an open habitat with some trees and an access to water.  In late May and June American Toads head to the water to mate and lay their eggs.

Often a small grove of trees in an otherwise grassy area can create a micro edge habitat. When examining the different tree species on

Eastern Cottontail Rabbit

the lower campus we can see that there are quite a few mature Red Oak trees, a number of Red Pines, and a number of different maple species including the Silver Maple, Red Maple and Norway Maple. All of these mature trees provide ecosystem services and create habitat for animals and insects. The oaks produce acorns that are one of the most nutritious foods in the local ecosystem and so many animals seek them out. It’s not only the squirrels but also the mice, raccoons and foxes that eat them as well.  Acorns are generally 8% protein and 37% fat. Blue Jays love acorns and are capable of hiding or burying up to 5000 acorns every year that they return to later in the winter to eat. Maple seeds are also nutritious and are consumed by mice and squirrels, and by many species of birds including chickadees.

The conifer tree species which mainly include Red Pines and Eastern White Cedars are important trees for nesting locations for birds. Songbirds are always looking for hiding places or cover to escape predators and conifer trees (especially the dense foliage of cedars) are the ideal places to run to in an emergency.

Any animal moving through the landscape prefers to follow the cover provided by trees and bushes.

The cottontail rabbits that exist on the campus use the brushy areas near the backyards of the homes and buildings on Maple avenue and then venture out into the grassy open areas of the campus on little forays to eat the abundant grasses and herbs. Mother rabbits make their nests in the brushy areas and can have up to 4 litters a year from April to September. And each litter contains typically 5 to 6 baby bunnies so one rabbit mother can often sire more than 20 rabbits a year. So they reproduce quickly but most rabbits don’t live longer than 15 months and the majority of them end up as dinner for Red Foxes or Coyotes.

Content for this page was made possible by the intercollegiate Campus Biodiversity Network Entente Canada-Quebec grant 2022-2023, spearheaded by Vanier College.  This project has been funded in part by Quebec’s ministère de l’Enseignement supérieur, through contributions from the Canada-Québec Agreement on Minority-Language Education and Second-Language Instruction


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