Protected conservation areas really do benefit a wide range of species and promote biodiversity, a study has found.
Researchers compared almost 2,000 sites inside and more than 4,500 outside 359 protected areas around the world.
They found that the protected areas contained 15% more individual animals and plants and 11% more species types than unprotected areas.
Dr Claudia Gray, from the University of Sussex, who co-led the study published in the journal Nature Communications, said: "Previously, regional or global studies of protected areas have mostly used information from satellite photos, to look at changes in forest cover. Instead, we used a particularly exciting new data set, which brings together information collected on the ground by hundreds of scientists all over the world.
"We have been able to show for the first time how protection affects thousands of species, including plants, mammals, birds and insects. This has provided us with important insights into these areas - which previous studies were not able to do."
The team also found that protection is most effective when human use of land for crops, pasture and plantations is kept to a minimum.
The research relied on a new global biodiversity database called Predicts ((Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) which holds more than 2.5 million biodiversity records spanning 48 countries.
Currently around 15% of the world's land and 3% of its oceans are protected. The Convention on Biological Diversity has pledged to increase this to at least 17% of land and 10% of oceans by 2020.
Co-author Professor Andy Purvis, from the Natural History Museum, London, said: "This study shows how important questions in conservation biology can be tackled by joining forces.
"Hundreds of scientists from dozens of countries have generously shared their hard-earned data with us. Each one of those data sets is like a piece of a jigsaw: the overall picture only becomes clear when you have all the pieces and can put them together."