HALIFAX — A pair of Canadian scientists say protected spaces on land and in the world's oceans are not enough to stem the worsening problem of biodiversity loss.

Peter Sale of the United Nations University says conservationists are relying too heavily on marine and terrestrial protected areas to address species decline.

In a paper published today, he and Camilo Mora of Dalhousie University in Halifax argue that species are still being lost at an alarming rate because of human activity.

Sale says that protecting areas on land and in the sea does little to shield species from pollution, climate change and acidification, which is harmful to marine life.

The authors say conservationists need to look at controlling human population, reducing demand on natural resources and slowing climate change.

Sale says the loss of biodiversity is still on the rise in some of the best-managed protected spaces, like the Great Barrier Reef.