Missing species show human impact on biodiversity greater than thought
A new global study, published yesterday in Nature , shows that in human-disturbed regions, many native plant species are missing from places where they could grow.
Traditional methods of measuring biodiversity-such as simply counting species present-do not give a complete picture. This is because they do not show which species are missing. An international team of researchers, including Utrecht ecologist Jonas Lembrechts , therefore developed a new approach. Besides mapping the plant species present, they also determined which species could potentially occur there. By looking at the difference, they got a picture of the missing biodiversity, which they call the "dark diversity."
Within the international collaborative DarkDivNet, more than 200 researchers collected data on dark diversity at 5,500 sites in 119 different regions worldwide. They then examined its relationship to the Human Footprint Index, a measure of the degree of human disturbance in a region.
The results show that a higher Human Footprint Index leads to a decrease in plant diversity even hundreds of kilometers away. In areas with little human influence, typically more than one-third of the possible plant species were present. But in regions heavily influenced by human activities, only one in five suitable species actually occurred.
Says Lembrechts, "By looking at the species that are missing rather than those that are, we gain a unique insight into the lost potential of our landscapes. This approach lets us see what has disappeared better than traditional methods. This is interesting for nature management: it allows us to target areas with high potential for biodiversity restoration and accurately monitor the success of restoration measures."
