Mayors attending the international COP 15 conference on preserving biodiversity say cities must be part of the solution.

Leaders from 14 cities around the world are in Montreal and are calling for national governments and the private sector to help increase spaces for nature in urban areas.

Experts acknowledge that cities face challenges when it comes to championing biodiversity, but they believe those obstacles can be overcome.

Across Canada there is concern over a need for housing, which has prompted the Ontario government to remove land from the protected Greenbelt to build more homes.