Great Canadian Parks / British Columbia

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The Parks / British Columbia / Gwaii Haanas National Park



 


 

One of the most significant threats to the unique biodiversity of these islands is the introduction of non-native species. Also called ‘exotics’, any species not naturally found in an environment exists without natural predators and can easily disrupt the ecosystem. On the Queen Charlotte Islands, 11 species of land mammals and approximately 25% of plants now present are not indigenous.

 

Deer, introduced around 1800 as a food source for European immigrants to the islands, have flourished in the absence of predators, and now number more than 60,000. The browsing deer totally clear the forest understory of new shoots and eat the berries that would normally be available for the bears, not only taking the traditional food of another species, but also inhibiting the forest's ability to replenish itself.

 

When the boon in raccoon fur did not occur, raccoons, introduced to the islands to improve fur trapping, flourished in the food abundant environment of Haida Gwaii. Their major prey is the seabirds and their eggs, burrow nesters being particularly vulnerable as their eggs are so accessible.

 

Rats that came to the Queen Charlottes by accident, in the holds of ships arriving from the mainland, have invaded 17 islands in the archipelago and have threatened or eliminated many of the seabird colonies. Colony nesting is one of the characteristics of seabirds, using the resources of the entire colony for feeding and protection. Unfortunately, it is this very trait which makes them such easy prey for the rats.

 

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