Some animal populations have profited from urbanization, but many have suffered. Some effects are obvious—for instance when animals are struck by cars. But others are much harder to see, like the destruction of habitats.
Some animal populations have profited from urbanization, but many have suffered. Some effects are obvious—for instance when animals are struck by cars. But others are much harder to see, like the destruction of habitats.

© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.

White Tailed Deer taste testing various plants kept in Moncton’s residences’ yards

With Moncton being such a rapidly growing city, wildlife have often had no choice but to adapt to the ever-growing subdivisions and retail building. White tailed deer have taken advantage of these areas by taste testing various plants kept in Moncton’s residences’ yards and gardens. You may often see deer in the subdivisions near Irishtown, Evergreen and Homestead Road.

© NB Department of Natural Resources

© 2013, "NB Department of Natural Resources". All Rights Reserved.


In cities, rainwater run-off is one of the principal sources of the toxic chemical substances found in urban waterways. When rain or melting snow washes over impermeable surfaces such as roads, roofs, parking lots, and sidewalks, it carries away a variety of pollutants. Oil, road salt, pesticides, fertilizer, domestic animal droppings, and other pollutants thus find their way into storm drains, which in turn empty into our lakes and waterways.

The repercussions on freshwater plants and wildlife are numerous. These pollutants can interfere with the breathing of both fish and aquatic invertebrates, damage the gills of fish, and increase the risk of infections and disease. Water run-off from urban areas can endanger the reproduction of both fish and mammals. It can cause congenital defects in a variety of species because of the chrome and other metals that it carries. As it washes away soil, it also causes damage to the aquatic environment, eroding river banks, for instance. The enormous quantities of sediment carried by rainwater run-off can also be deposited on the spawning areas of fish, diminishing or even eliminating their chances of reproducing.
In cities, rainwater run-off is one of the principal sources of the toxic chemical substances found in urban waterways. When rain or melting snow washes over impermeable surfaces such as roads, roofs, parking lots, and sidewalks, it carries away a variety of pollutants. Oil, road salt, pesticides, fertilizer, domestic animal droppings, and other pollutants thus find their way into storm drains, which in turn empty into our lakes and waterways.

The repercussions on freshwater plants and wildlife are numerous. These pollutants can interfere with the breathing of both fish and aquatic invertebrates, damage the gills of fish, and increase the risk of infections and disease. Water run-off from urban areas can endanger the reproduction of both fish and mammals. It can cause congenital defects in a variety of species because of the chrome and other metals that it carries. As it washes away soil, it also causes damage to the aquatic environment, eroding river banks, for instance. The enormous quantities of sediment carried by rainwater run-off can also be deposited on the spawning areas of fish, diminishing or even eliminating their chances of reproducing.

Source : http://www.cwf-fcf.org/fr/action/conscience/rivieres-et-des-oceans/learn/pollution/urban-runoff.html


© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.

Building condominiums near the edge of a marsh, Vernon, Canada

The spacious open grassland hills that once offered clean and simple views of nature from downtown, are now being scarred with roads and punctuated with large houses. Marsh lands once considered unsuitable are now being filled to create building spots, with marsh grasses remaining just beyond the new lots.

Okanagan Science Centre

© Cuyler Page. All Rights Reserved.


The introduction of exotic species into Quebec has been greatly helped by globalization and our ever-increasing trade abroad. Although a species can certainly be moved from its usual range by natural phenomenon such as floods, the majority of introductions are caused by human activity. Introductions can be intentional: for example, sometimes biological control agents or domestic species that have been hunted or fished are released into the wild, with or without permission. They can also be introduced accidentally, when they escape from game ranches or fish farms, or have been transported in cargo such as construction material.

Many exotic species pose no threat.  Nonetheless, when they cause damage to the environment, the economy, or our society, they are termed “invasive alien species,” (IAS). Exotic fauna can be terrestrial species, such as the Japanese Ladybug, the Emerald Ash Borer, or the Common Starling. There are also aquatic species, such as the Zebra Mussel or the Round Goby. IAS also include pathogens that attack wildlife, such as the variant of the rabies virus that affects raccoons.

In many parts of the world, the damage caused by Read More
The introduction of exotic species into Quebec has been greatly helped by globalization and our ever-increasing trade abroad. Although a species can certainly be moved from its usual range by natural phenomenon such as floods, the majority of introductions are caused by human activity. Introductions can be intentional: for example, sometimes biological control agents or domestic species that have been hunted or fished are released into the wild, with or without permission. They can also be introduced accidentally, when they escape from game ranches or fish farms, or have been transported in cargo such as construction material.

Many exotic species pose no threat.  Nonetheless, when they cause damage to the environment, the economy, or our society, they are termed “invasive alien species,” (IAS). Exotic fauna can be terrestrial species, such as the Japanese Ladybug, the Emerald Ash Borer, or the Common Starling. There are also aquatic species, such as the Zebra Mussel or the Round Goby. IAS also include pathogens that attack wildlife, such as the variant of the rabies virus that affects raccoons.

In many parts of the world, the damage caused by invasive alien species is considerable, from ecological, the economic, and social perspectives. The Convention on Biological Diversity considers IAS as the second greatest menace to biodiversity, second only to the destruction of habitat.

Invasive alien species compete with native species. Once an IAS becomes established in an ecosystem that it finds favourable, it is almost impossible to remove, and very costly even to control.


© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.

An invasive alien species in Sherbrooke : Black slug (Arion ater)

These black slugs (Arion ater) are not native to Quebec. They were accidently imported from Europe in wooden cases that were shipped to the Université de Sherbrooke.

Sherbrooke museum of nature and science

© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.


The population density of cats (whether domesticated or feral) varies according to the degree of urbanization. In a rural zone, the density of cats is usually below 5 cats/km2. In cities, cat densities are usually above 50 cats/km2, and may even reach values near 300 cats/km2. The main impact of the introduction of cats is the predation pressure they place on native species. Another important impact is their role in spreading diseases to other animals—including humans—such as rabies, Lyme disease, toxoplasmosis, and the feline immunodeficiency virus.
The population density of cats (whether domesticated or feral) varies according to the degree of urbanization. In a rural zone, the density of cats is usually below 5 cats/km2. In cities, cat densities are usually above 50 cats/km2, and may even reach values near 300 cats/km2. The main impact of the introduction of cats is the predation pressure they place on native species. Another important impact is their role in spreading diseases to other animals—including humans—such as rabies, Lyme disease, toxoplasmosis, and the feline immunodeficiency virus.

© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.

Domestic cat hunting birds on a balcony

Population density of cats varies according to the degree of urbanization. The primary repercussions of the introduction of cats are the predation pressure they place on native species, and their role in spreading disease to other animals.

Christiane Piatera

© 2013, Christiane Piatera. All Rights Reserved.


Conduct research to discover the animals in your region that have benefited—or suffered—from the presence of the city. What solutions could you propose to your community for sharing the area with the surrounding wildlife in a harmonious way?
Conduct research to discover the animals in your region that have benefited—or suffered—from the presence of the city. What solutions could you propose to your community for sharing the area with the surrounding wildlife in a harmonious way?

© 2013, "Sherbrooke museum of nature and science". All Rights Reserved.

Grey Squirrel searching for provisions in a garbage in a city park

A grey squirrel, searching for provisions in preparation for winter.

Sherbrooke museum of nature and science

© 2013, Véronique Piatera. All Rights Reserved.


Learning Objectives

Identify the effects of urbanization on wildlife. Become acquainted with the concepts of fragmentation of habitat, pollution, and the introduction of invasive alien species.


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