While ecologists believe invasive species play a major role in more than 60% of plant and animal extinctions, stopping them in their tracks is almost impossible. Biodiversity reporter Phoebe Weston tells Madeleine Finlay how invasive species spread, how conservationists are trying combat them and why some think a radical new approach is needed.

While ecologists believe invasive species play a major role in more than 60% of plant and animal extinctions, stopping them in their tracks is almost impossible. Biodiversity reporter Phoebe Weston tells Madeleine Finlay how invasive species spread, how conservationists are trying combat them and why some think a radical new approach is needed.