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Exotic Species
Red-eared slider, Trachemys scripta elegans.
Red-eared slider, Trachemys scripta elegans.

Aquarium Evictions
Occasionally, pet owners spread exotic species by dumping aquarium fish, turtles and plants into the River. In just one day, researchers have seen as many as seven red-eared sliders along the Rideau River. The more exotic species spread, the bigger a problem they become. If you no longer wish to keep your aquarium animals and plants, give them to a friend or bring them to a pet shop.

 

Intruders

Even though scientists are generally thrilled about finding new species, it can also cause them to worry. This is the case when they find that non-native organisms have been introduced into an ecosystem. These newcomers are called exotic species.

Flowering rush, Butomus umbellatus.
The flowering rush (Butomus umbellatus) is a large plant with pink flowers and is dominant along the shorelines of downtown Ottawa.

Results gathered from research conducted in Ontario show that 91% of these newcomers are unable to live or nest in their new environment. [2] Species that are able to do so often cause great damage to the ecosystem.

Some exotic species are described as "invasive". These species are able to thrive and spread, usually because food is abundant, and there are few (if any) predators, illnesses or parasites in the new habitat.

Several of these invasive species reproduce prolifically. For example, each mature purple loosestrife plant produces 2 million seeds every time it blossoms. Eurasian water milfoil is able to grow from seeds, and fragments of root and stem are able to take root and grow. [3, 4, 5, 6]

Strong Competition
Zebra mussels (Dreissena polymorpha) on a native mussel.
Zebra mussels (Dreissena polymorpha) clustered on a native mussel.

Exotic species are often able to supplant native species, thereby leaving the native species with fewer nesting sites and food resources. In downtown Ottawa for example, the flowering rush has multiplied along the shorelines of the Rideau River at the expense of native aquatic plants.

In addition, some exotics can harm a native species directly. Zebra mussels, for example, often fasten themselves in clusters on the shells of native mussels. The unfortunate animals are thus prevented from breathing, feeding and moving, and so they die.

Exotic species spread through several means. Some spread naturally with the current, as seen with fragments of Eurasian water milfoil or zebra mussel larvae. They can also be transported to other bodies of water in bait buckets or live wells, or attached to boat hulls and propellers.

Learn which exotic species were found in the Rideau River during the Rideau River Biodiversity Project and what you can do to help prevent their spread.

Questions about exotic species? Call the exotic species hotline of the Ontario Ministry of Natural Resources and the Ontario Federation of Anglers and Hunters: 1.800.563.7711.

 

 Exotic Species
Bullet.
Bullet.
 Don't Overlook...
Arrow.
Arrow.


 Newcomers  
Arrow.  
Arrow.  
Arrow.  
Arrow.  
Arrow.  
Arrow.  


European frogbit, Hydrocharis morsus-ranae.
A flower of European frogbit (Hydrocharis morsus-ranae), which is an exotic aquatic plant.

The Rideau River Gets Top Billing!
The video Rivers: Reflections of Life uncovers the wealth of plants and animals that live in rivers! Framed by the main stages of the Rideau River Biodiversity Project, the video illustrates how humans can live in harmony with the river, while protecting its biodiversity for future generations. The video was produced by the Canadian Museum of Nature, and you can order it online.


A Project of the Canadian Museum of Nature
  
 Images: Canadian Museum of Nature, Thomas Cook, Lynn Gillespie, Jean Lauriault