Several dozen beavers are thought to be living in Vancouver, some of them making themselves at home in restored marshland near the Olympic Village, and now the city's park's board has approved a strategy that will give them some company.

The Vancouver Park Board has approved a detailed strategy to enhance and expand coastlines, forests and wetlands across the city. The Biodiversity Strategy aims to restore 25 hectares of natural land by 2020 – much of it spread across various shorelines – as well as tackle forest restoration near the Fraser River.

"There's lots of evidence that there are physical and mental benefits for those who access nature in their daily lives," biologist Nick Page, of the parks board, said in an interview. "Compared to rural populations, there are few points of access to nature in the city."

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Mr. Page was a major architect of the plan, which also aims to combat invasive species, while simultaneously helping native species adapt to near-urban life.

Although invasive organisms, such as Himalayan blackberries or Japanese knotweed, can cause ecological damage, sometimes native species can cause just as much trouble near urban environments.

This year in Saskatchewan, for example, more than $500,000 of provincial funds have been set aside to control and cull problem beaver populations. They can cause incredible infrastructure damage by building dams that can create subsequent floods.

"The problem comes when beavers start working on natural water courses," said Wayne Goodey, a University of British Columbia lecturer with a background in animal psychology. "In general ecological principles, even a couple of animals can do a large amount of damage to the landscaping."

Mr. Page, however, is confident that adaptation, not relocation, is the best strategy for these local beavers.

"There's not really an opportunity for them to dam anything, and if they do, there's very little chance of them flooding important infrastructure," he said. "Relocation is very expensive, $10,000 each beaver. You can protect a lot of trees and clean out a lot of culverts for that price."

Elsewhere in Canada's big cities, Calgary's verdant Elbow and Bow Rivers offer prime habitat to approximately 200 beavers.

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Winnipeg has about 100 beavers within its city limits and, like most other jurisdictions, manages the loss of vegetation by wrapping trunks with protective wire.

The City of Toronto doesn't keep track of its urban beaver population, but a city guide to its mammals says the aquatic animal is commonly seen along the shoreline of Lake Ontario and throughout the city's streams and corridors.

The animal is North America's largest rodent and a lone beaver can fell more than 200 trees a year, making them a formidable influence on waterfront flora.

"Beavers are ecosystem engineers," Mr. Page said. "And they are local celebrities now, too."

With a report from The Canadian Press