Victoria Gill is a science correspondent.
The largest ever study of protected areas has shown that most do not benefit wildlife.
Scientists looked at the impact of protected areas on wetlands and waterbirds.
They found that success varied greatly around the world and depended on how an area was managed.
The authors say that habitats need to be managed in ways that give a boost to nature.
There need to be rules in place and restoration according to the lead researcher.
We can't just draw a line around an area and say, "you can't build a car park here."
The study used population trends of wetlands birds as a measure of the success of a protected area, which can be anything from an area of outstanding natural beauty to a carefully managed nature reserve.
She and her colleagues compared sites before and after they were protected, and compared the trends of similar bird populations inside and outside protected areas.
She told the news that wildlife populations in the majority of places were stable or increasing, but they weren't doing any better than in protected areas.
That is disappointing, but not surprising. People are talking about how much land is protected, but not so much about whether those areas are doing anything positive.
One million species of plants and animals are at risk according to the UN.
Next month, world leaders will gather in China to set the agenda for the next decade. Many countries are aligning themselves with a goal of protecting 30% of the Earth's surface by the year 2030.
The scientists say this won't guarantee the preservation of biodiversity.
They say that the targets need to be set for the quality of the protected areas. Setting goals for increasing the diversity of plant and animal species in an area is one way to measure success.
Drawing lines on a map does nothing for nature according to co-author Prof Julia Jones.
She said that an obsession with reaching a certain area-based target without a focus on improving the condition of existing protected areas will achieve little.
When world leaders gather in China later this year to set targets for the next decade, I really hope to see a focus on effectiveness of protected areas, rather than simply how much surface area is devoted to them.
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