A team of scientists examined 100 long-term monitoring studies that together contained six million observations of more than 35,000 species – including datasets from as early as 1874 – from the tropics to the poles, on land and in the sea. They found that in 59 of them, the biological communities under study showed an increase in species richness and 41 a decrease. However, they also found that almost 80 per cent of the communities had undergone substantial changes in species composition – changing by an average of about ten per cent per decade, a rate significantly higher than that predicted by models.
‘A main policy application of this work is that we’re going to need to focus as much on the identity of species as on the number of species,’ said co-author Nick Gotelli of the University of Vermont. ‘The number of species in a place may not be our best scorecard for environmental change.
‘In the oceans, we no longer have many anchovies, but we seem to have an awful lot of jellyfish,’ he continued. ‘Those kinds of changes are not going to be seen by just counting the number of species that are present.’
This story was published in the July 2014 edition of Geographical Magazine