Islands of evolution in a hurry

“They’re like islands in a sea of forest,” said Santiago Madriñán,an expert on Páramos at the University of the Andes in Colombia. All told,Páramos cover about 13,500 square-miles. Madriñán and other researchers have found 3,431 species of vascular plants,most of them found nowhere else on Earth. The Páramos are home to strange variations on familiar forms,such as a daisy known as Espeletia uribei that grows as tall as trees.

Scientists have long known that in certain spots,evolution runs faster than normal. The Galápagos Islands,for example,are home to some 13 species of Darwin’s finches,which all evolved from a single group of birds that originally colonised them.

To measure its speed,researchers have looked at the DNA of species living in each place. The longer it has been since two species diverged from a common ancestor,the more time each lineage has had to accumulate mutations. Young species have relatively few mutations.

To calculate the speed of evolution in the Páramos,Madriñán and his colleagues surveyed 13 different lineages of plants that grow there. They estimated the rate at which species had split from each other in each lineage,and then combined those estimates. They then looked at data from other fast-evolving places,such as Hawaii and the Mediterranean coast.

The results surpassed Madriñán’s suspicions. The Páramos weren’t just home to fast evolution,it turned out. Of the eight places he and his colleagues compared,the Páramos are evolving the fastest of all.